MIPS: BCM1480: Remove checks for CONFIG_SIBYTE_BCM1480_PROF
[linux/fpc-iii.git] / kernel / trace / trace_kprobe.c
blob903ae28962be7f513c2a382631da4da2aeef377e
1 /*
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"
27 /**
28 * Kprobe event core functions
30 struct trace_kprobe {
31 struct list_head list;
32 struct kretprobe rp; /* Use rp.kp for kprobe use */
33 unsigned long nhit;
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,
64 struct module *mod)
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 */
87 struct symbol_cache {
88 char *symbol;
89 long offset;
90 unsigned long addr;
93 unsigned long update_symbol_cache(struct symbol_cache *sc)
95 sc->addr = (unsigned long)kallsyms_lookup_name(sc->symbol);
97 if (sc->addr)
98 sc->addr += sc->offset;
100 return sc->addr;
103 void free_symbol_cache(struct symbol_cache *sc)
105 kfree(sc->symbol);
106 kfree(sc);
109 struct symbol_cache *alloc_symbol_cache(const char *sym, long offset)
111 struct symbol_cache *sc;
113 if (!sym || strlen(sym) == 0)
114 return NULL;
116 sc = kzalloc(sizeof(struct symbol_cache), GFP_KERNEL);
117 if (!sc)
118 return NULL;
120 sc->symbol = kstrdup(sym, GFP_KERNEL);
121 if (!sc->symbol) {
122 kfree(sc);
123 return NULL;
125 sc->offset = offset;
126 update_symbol_cache(sc);
128 return 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) \
150 type retval; \
151 if (probe_kernel_address(addr, retval)) \
152 *(type *)dest = 0; \
153 else \
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)
164 long ret;
165 int maxlen = get_rloc_len(*(u32 *)dest);
166 u8 *dst = get_rloc_data(dest);
167 u8 *src = addr;
168 mm_segment_t old_fs = get_fs();
170 if (!maxlen)
171 return;
174 * Try to get string again, since the string can be changed while
175 * probing.
177 set_fs(KERNEL_DS);
178 pagefault_disable();
181 ret = __copy_from_user_inatomic(dst++, src++, 1);
182 while (dst[-1] && ret == 0 && src - (u8 *)addr < maxlen);
184 dst[-1] = '\0';
185 pagefault_enable();
186 set_fs(old_fs);
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));
191 } else {
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)
201 mm_segment_t old_fs;
202 int ret, len = 0;
203 u8 c;
205 old_fs = get_fs();
206 set_fs(KERNEL_DS);
207 pagefault_disable();
209 do {
210 ret = __copy_from_user_inatomic(&c, (u8 *)addr + len, 1);
211 len++;
212 } while (c && ret == 0 && len < MAX_STRING_SIZE);
214 pagefault_enable();
215 set_fs(old_fs);
217 if (ret < 0) /* Failed to check the length */
218 *(u32 *)dest = 0;
219 else
220 *(u32 *)dest = len;
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; \
228 if (sc->addr) \
229 fetch_memory_##type(regs, (void *)sc->addr, dest); \
230 else \
231 *(type *)dest = 0; \
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[] = {
247 /* Special types */
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"),
252 /* Basic types */
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,
269 const char *event,
270 void *addr,
271 const char *symbol,
272 unsigned long offs,
273 int nargs, bool is_return)
275 struct trace_kprobe *tk;
276 int ret = -ENOMEM;
278 tk = kzalloc(SIZEOF_TRACE_KPROBE(nargs), GFP_KERNEL);
279 if (!tk)
280 return ERR_PTR(ret);
282 if (symbol) {
283 tk->symbol = kstrdup(symbol, GFP_KERNEL);
284 if (!tk->symbol)
285 goto error;
286 tk->rp.kp.symbol_name = tk->symbol;
287 tk->rp.kp.offset = offs;
288 } else
289 tk->rp.kp.addr = addr;
291 if (is_return)
292 tk->rp.handler = kretprobe_dispatcher;
293 else
294 tk->rp.kp.pre_handler = kprobe_dispatcher;
296 if (!event || !is_good_name(event)) {
297 ret = -EINVAL;
298 goto error;
301 tk->tp.call.class = &tk->tp.class;
302 tk->tp.call.name = kstrdup(event, GFP_KERNEL);
303 if (!tk->tp.call.name)
304 goto error;
306 if (!group || !is_good_name(group)) {
307 ret = -EINVAL;
308 goto error;
311 tk->tp.class.system = kstrdup(group, GFP_KERNEL);
312 if (!tk->tp.class.system)
313 goto error;
315 INIT_LIST_HEAD(&tk->list);
316 INIT_LIST_HEAD(&tk->tp.files);
317 return tk;
318 error:
319 kfree(tk->tp.call.name);
320 kfree(tk->symbol);
321 kfree(tk);
322 return ERR_PTR(ret);
325 static void free_trace_kprobe(struct trace_kprobe *tk)
327 int i;
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);
334 kfree(tk->symbol);
335 kfree(tk);
338 static struct trace_kprobe *find_trace_kprobe(const char *event,
339 const char *group)
341 struct trace_kprobe *tk;
343 list_for_each_entry(tk, &probe_list, list)
344 if (strcmp(ftrace_event_name(&tk->tp.call), event) == 0 &&
345 strcmp(tk->tp.call.class->system, group) == 0)
346 return tk;
347 return NULL;
351 * Enable trace_probe
352 * if the file is NULL, enable "perf" handler, or enable "trace" handler.
354 static int
355 enable_trace_kprobe(struct trace_kprobe *tk, struct ftrace_event_file *file)
357 int ret = 0;
359 if (file) {
360 struct event_file_link *link;
362 link = kmalloc(sizeof(*link), GFP_KERNEL);
363 if (!link) {
364 ret = -ENOMEM;
365 goto out;
368 link->file = file;
369 list_add_tail_rcu(&link->list, &tk->tp.files);
371 tk->tp.flags |= TP_FLAG_TRACE;
372 } else
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);
378 else
379 ret = enable_kprobe(&tk->rp.kp);
381 out:
382 return ret;
386 * Disable trace_probe
387 * if the file is NULL, disable "perf" handler, or disable "trace" handler.
389 static int
390 disable_trace_kprobe(struct trace_kprobe *tk, struct ftrace_event_file *file)
392 struct event_file_link *link = NULL;
393 int wait = 0;
394 int ret = 0;
396 if (file) {
397 link = find_event_file_link(&tk->tp, file);
398 if (!link) {
399 ret = -EINVAL;
400 goto out;
403 list_del_rcu(&link->list);
404 wait = 1;
405 if (!list_empty(&tk->tp.files))
406 goto out;
408 tk->tp.flags &= ~TP_FLAG_TRACE;
409 } else
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);
415 else
416 disable_kprobe(&tk->rp.kp);
417 wait = 1;
419 out:
420 if (wait) {
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.
429 synchronize_sched();
430 kfree(link); /* Ignored if link == NULL */
433 return ret;
436 /* Internal register function - just handle k*probes and flags */
437 static int __register_trace_kprobe(struct trace_kprobe *tk)
439 int i, ret;
441 if (trace_probe_is_registered(&tk->tp))
442 return -EINVAL;
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;
450 else
451 tk->rp.kp.flags |= KPROBE_FLAG_DISABLED;
453 if (trace_kprobe_is_return(tk))
454 ret = register_kretprobe(&tk->rp);
455 else
456 ret = register_kprobe(&tk->rp.kp);
458 if (ret == 0)
459 tk->tp.flags |= TP_FLAG_REGISTERED;
460 else {
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");
466 ret = 0;
467 } else if (ret == -EILSEQ) {
468 pr_warning("Probing address(0x%p) is not an "
469 "instruction boundary.\n",
470 tk->rp.kp.addr);
471 ret = -EINVAL;
475 return ret;
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);
484 else
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))
498 return -EBUSY;
500 /* Will fail if probe is being used by ftrace or perf */
501 if (unregister_kprobe_event(tk))
502 return -EBUSY;
504 __unregister_trace_kprobe(tk);
505 list_del(&tk->list);
507 return 0;
510 /* Register a trace_probe and probe_event */
511 static int register_trace_kprobe(struct trace_kprobe *tk)
513 struct trace_kprobe *old_tk;
514 int ret;
516 mutex_lock(&probe_lock);
518 /* Delete old (same name) event if exist */
519 old_tk = find_trace_kprobe(ftrace_event_name(&tk->tp.call),
520 tk->tp.call.class->system);
521 if (old_tk) {
522 ret = unregister_trace_kprobe(old_tk);
523 if (ret < 0)
524 goto end;
525 free_trace_kprobe(old_tk);
528 /* Register new event */
529 ret = register_kprobe_event(tk);
530 if (ret) {
531 pr_warning("Failed to register probe event(%d)\n", ret);
532 goto end;
535 /* Register k*probe */
536 ret = __register_trace_kprobe(tk);
537 if (ret < 0)
538 unregister_kprobe_event(tk);
539 else
540 list_add_tail(&tk->list, &probe_list);
542 end:
543 mutex_unlock(&probe_lock);
544 return ret;
547 /* Module notifier call back, checking event on the module */
548 static int trace_kprobe_module_callback(struct notifier_block *nb,
549 unsigned long val, void *data)
551 struct module *mod = data;
552 struct trace_kprobe *tk;
553 int ret;
555 if (val != MODULE_STATE_COMING)
556 return NOTIFY_DONE;
558 /* Update probes on coming module */
559 mutex_lock(&probe_lock);
560 list_for_each_entry(tk, &probe_list, list) {
561 if (trace_kprobe_within_module(tk, mod)) {
562 /* Don't need to check busy - this should have gone. */
563 __unregister_trace_kprobe(tk);
564 ret = __register_trace_kprobe(tk);
565 if (ret)
566 pr_warning("Failed to re-register probe %s on"
567 "%s: %d\n",
568 ftrace_event_name(&tk->tp.call),
569 mod->name, ret);
572 mutex_unlock(&probe_lock);
574 return NOTIFY_DONE;
577 static struct notifier_block trace_kprobe_module_nb = {
578 .notifier_call = trace_kprobe_module_callback,
579 .priority = 1 /* Invoked after kprobe module callback */
582 static int create_trace_kprobe(int argc, char **argv)
585 * Argument syntax:
586 * - Add kprobe: p[:[GRP/]EVENT] [MOD:]KSYM[+OFFS]|KADDR [FETCHARGS]
587 * - Add kretprobe: r[:[GRP/]EVENT] [MOD:]KSYM[+0] [FETCHARGS]
588 * Fetch args:
589 * $retval : fetch return value
590 * $stack : fetch stack address
591 * $stackN : fetch Nth of stack (N:0-)
592 * @ADDR : fetch memory at ADDR (ADDR should be in kernel)
593 * @SYM[+|-offs] : fetch memory at SYM +|- offs (SYM is a data symbol)
594 * %REG : fetch register REG
595 * Dereferencing memory fetch:
596 * +|-offs(ARG) : fetch memory at ARG +|- offs address.
597 * Alias name of args:
598 * NAME=FETCHARG : set NAME as alias of FETCHARG.
599 * Type of args:
600 * FETCHARG:TYPE : use TYPE instead of unsigned long.
602 struct trace_kprobe *tk;
603 int i, ret = 0;
604 bool is_return = false, is_delete = false;
605 char *symbol = NULL, *event = NULL, *group = NULL;
606 char *arg;
607 unsigned long offset = 0;
608 void *addr = NULL;
609 char buf[MAX_EVENT_NAME_LEN];
611 /* argc must be >= 1 */
612 if (argv[0][0] == 'p')
613 is_return = false;
614 else if (argv[0][0] == 'r')
615 is_return = true;
616 else if (argv[0][0] == '-')
617 is_delete = true;
618 else {
619 pr_info("Probe definition must be started with 'p', 'r' or"
620 " '-'.\n");
621 return -EINVAL;
624 if (argv[0][1] == ':') {
625 event = &argv[0][2];
626 if (strchr(event, '/')) {
627 group = event;
628 event = strchr(group, '/') + 1;
629 event[-1] = '\0';
630 if (strlen(group) == 0) {
631 pr_info("Group name is not specified\n");
632 return -EINVAL;
635 if (strlen(event) == 0) {
636 pr_info("Event name is not specified\n");
637 return -EINVAL;
640 if (!group)
641 group = KPROBE_EVENT_SYSTEM;
643 if (is_delete) {
644 if (!event) {
645 pr_info("Delete command needs an event name.\n");
646 return -EINVAL;
648 mutex_lock(&probe_lock);
649 tk = find_trace_kprobe(event, group);
650 if (!tk) {
651 mutex_unlock(&probe_lock);
652 pr_info("Event %s/%s doesn't exist.\n", group, event);
653 return -ENOENT;
655 /* delete an event */
656 ret = unregister_trace_kprobe(tk);
657 if (ret == 0)
658 free_trace_kprobe(tk);
659 mutex_unlock(&probe_lock);
660 return ret;
663 if (argc < 2) {
664 pr_info("Probe point is not specified.\n");
665 return -EINVAL;
667 if (isdigit(argv[1][0])) {
668 if (is_return) {
669 pr_info("Return probe point must be a symbol.\n");
670 return -EINVAL;
672 /* an address specified */
673 ret = kstrtoul(&argv[1][0], 0, (unsigned long *)&addr);
674 if (ret) {
675 pr_info("Failed to parse address.\n");
676 return ret;
678 } else {
679 /* a symbol specified */
680 symbol = argv[1];
681 /* TODO: support .init module functions */
682 ret = traceprobe_split_symbol_offset(symbol, &offset);
683 if (ret) {
684 pr_info("Failed to parse symbol.\n");
685 return ret;
687 if (offset && is_return) {
688 pr_info("Return probe must be used without offset.\n");
689 return -EINVAL;
692 argc -= 2; argv += 2;
694 /* setup a probe */
695 if (!event) {
696 /* Make a new event name */
697 if (symbol)
698 snprintf(buf, MAX_EVENT_NAME_LEN, "%c_%s_%ld",
699 is_return ? 'r' : 'p', symbol, offset);
700 else
701 snprintf(buf, MAX_EVENT_NAME_LEN, "%c_0x%p",
702 is_return ? 'r' : 'p', addr);
703 event = buf;
705 tk = alloc_trace_kprobe(group, event, addr, symbol, offset, argc,
706 is_return);
707 if (IS_ERR(tk)) {
708 pr_info("Failed to allocate trace_probe.(%d)\n",
709 (int)PTR_ERR(tk));
710 return PTR_ERR(tk);
713 /* parse arguments */
714 ret = 0;
715 for (i = 0; i < argc && i < MAX_TRACE_ARGS; i++) {
716 struct probe_arg *parg = &tk->tp.args[i];
718 /* Increment count for freeing args in error case */
719 tk->tp.nr_args++;
721 /* Parse argument name */
722 arg = strchr(argv[i], '=');
723 if (arg) {
724 *arg++ = '\0';
725 parg->name = kstrdup(argv[i], GFP_KERNEL);
726 } else {
727 arg = argv[i];
728 /* If argument name is omitted, set "argN" */
729 snprintf(buf, MAX_EVENT_NAME_LEN, "arg%d", i + 1);
730 parg->name = kstrdup(buf, GFP_KERNEL);
733 if (!parg->name) {
734 pr_info("Failed to allocate argument[%d] name.\n", i);
735 ret = -ENOMEM;
736 goto error;
739 if (!is_good_name(parg->name)) {
740 pr_info("Invalid argument[%d] name: %s\n",
741 i, parg->name);
742 ret = -EINVAL;
743 goto error;
746 if (traceprobe_conflict_field_name(parg->name,
747 tk->tp.args, i)) {
748 pr_info("Argument[%d] name '%s' conflicts with "
749 "another field.\n", i, argv[i]);
750 ret = -EINVAL;
751 goto error;
754 /* Parse fetch argument */
755 ret = traceprobe_parse_probe_arg(arg, &tk->tp.size, parg,
756 is_return, true);
757 if (ret) {
758 pr_info("Parse error at argument[%d]. (%d)\n", i, ret);
759 goto error;
763 ret = register_trace_kprobe(tk);
764 if (ret)
765 goto error;
766 return 0;
768 error:
769 free_trace_kprobe(tk);
770 return ret;
773 static int release_all_trace_kprobes(void)
775 struct trace_kprobe *tk;
776 int ret = 0;
778 mutex_lock(&probe_lock);
779 /* Ensure no probe is in use. */
780 list_for_each_entry(tk, &probe_list, list)
781 if (trace_probe_is_enabled(&tk->tp)) {
782 ret = -EBUSY;
783 goto end;
785 /* TODO: Use batch unregistration */
786 while (!list_empty(&probe_list)) {
787 tk = list_entry(probe_list.next, struct trace_kprobe, list);
788 ret = unregister_trace_kprobe(tk);
789 if (ret)
790 goto end;
791 free_trace_kprobe(tk);
794 end:
795 mutex_unlock(&probe_lock);
797 return ret;
800 /* Probes listing interfaces */
801 static void *probes_seq_start(struct seq_file *m, loff_t *pos)
803 mutex_lock(&probe_lock);
804 return seq_list_start(&probe_list, *pos);
807 static void *probes_seq_next(struct seq_file *m, void *v, loff_t *pos)
809 return seq_list_next(v, &probe_list, pos);
812 static void probes_seq_stop(struct seq_file *m, void *v)
814 mutex_unlock(&probe_lock);
817 static int probes_seq_show(struct seq_file *m, void *v)
819 struct trace_kprobe *tk = v;
820 int i;
822 seq_printf(m, "%c", trace_kprobe_is_return(tk) ? 'r' : 'p');
823 seq_printf(m, ":%s/%s", tk->tp.call.class->system,
824 ftrace_event_name(&tk->tp.call));
826 if (!tk->symbol)
827 seq_printf(m, " 0x%p", tk->rp.kp.addr);
828 else if (tk->rp.kp.offset)
829 seq_printf(m, " %s+%u", trace_kprobe_symbol(tk),
830 tk->rp.kp.offset);
831 else
832 seq_printf(m, " %s", trace_kprobe_symbol(tk));
834 for (i = 0; i < tk->tp.nr_args; i++)
835 seq_printf(m, " %s=%s", tk->tp.args[i].name, tk->tp.args[i].comm);
836 seq_printf(m, "\n");
838 return 0;
841 static const struct seq_operations probes_seq_op = {
842 .start = probes_seq_start,
843 .next = probes_seq_next,
844 .stop = probes_seq_stop,
845 .show = probes_seq_show
848 static int probes_open(struct inode *inode, struct file *file)
850 int ret;
852 if ((file->f_mode & FMODE_WRITE) && (file->f_flags & O_TRUNC)) {
853 ret = release_all_trace_kprobes();
854 if (ret < 0)
855 return ret;
858 return seq_open(file, &probes_seq_op);
861 static ssize_t probes_write(struct file *file, const char __user *buffer,
862 size_t count, loff_t *ppos)
864 return traceprobe_probes_write(file, buffer, count, ppos,
865 create_trace_kprobe);
868 static const struct file_operations kprobe_events_ops = {
869 .owner = THIS_MODULE,
870 .open = probes_open,
871 .read = seq_read,
872 .llseek = seq_lseek,
873 .release = seq_release,
874 .write = probes_write,
877 /* Probes profiling interfaces */
878 static int probes_profile_seq_show(struct seq_file *m, void *v)
880 struct trace_kprobe *tk = v;
882 seq_printf(m, " %-44s %15lu %15lu\n",
883 ftrace_event_name(&tk->tp.call), tk->nhit,
884 tk->rp.kp.nmissed);
886 return 0;
889 static const struct seq_operations profile_seq_op = {
890 .start = probes_seq_start,
891 .next = probes_seq_next,
892 .stop = probes_seq_stop,
893 .show = probes_profile_seq_show
896 static int profile_open(struct inode *inode, struct file *file)
898 return seq_open(file, &profile_seq_op);
901 static const struct file_operations kprobe_profile_ops = {
902 .owner = THIS_MODULE,
903 .open = profile_open,
904 .read = seq_read,
905 .llseek = seq_lseek,
906 .release = seq_release,
909 /* Kprobe handler */
910 static __kprobes void
911 __kprobe_trace_func(struct trace_kprobe *tk, struct pt_regs *regs,
912 struct ftrace_event_file *ftrace_file)
914 struct kprobe_trace_entry_head *entry;
915 struct ring_buffer_event *event;
916 struct ring_buffer *buffer;
917 int size, dsize, pc;
918 unsigned long irq_flags;
919 struct ftrace_event_call *call = &tk->tp.call;
921 WARN_ON(call != ftrace_file->event_call);
923 if (ftrace_trigger_soft_disabled(ftrace_file))
924 return;
926 local_save_flags(irq_flags);
927 pc = preempt_count();
929 dsize = __get_data_size(&tk->tp, regs);
930 size = sizeof(*entry) + tk->tp.size + dsize;
932 event = trace_event_buffer_lock_reserve(&buffer, ftrace_file,
933 call->event.type,
934 size, irq_flags, pc);
935 if (!event)
936 return;
938 entry = ring_buffer_event_data(event);
939 entry->ip = (unsigned long)tk->rp.kp.addr;
940 store_trace_args(sizeof(*entry), &tk->tp, regs, (u8 *)&entry[1], dsize);
942 event_trigger_unlock_commit_regs(ftrace_file, buffer, event,
943 entry, irq_flags, pc, regs);
946 static __kprobes void
947 kprobe_trace_func(struct trace_kprobe *tk, struct pt_regs *regs)
949 struct event_file_link *link;
951 list_for_each_entry_rcu(link, &tk->tp.files, list)
952 __kprobe_trace_func(tk, regs, link->file);
955 /* Kretprobe handler */
956 static __kprobes void
957 __kretprobe_trace_func(struct trace_kprobe *tk, struct kretprobe_instance *ri,
958 struct pt_regs *regs,
959 struct ftrace_event_file *ftrace_file)
961 struct kretprobe_trace_entry_head *entry;
962 struct ring_buffer_event *event;
963 struct ring_buffer *buffer;
964 int size, pc, dsize;
965 unsigned long irq_flags;
966 struct ftrace_event_call *call = &tk->tp.call;
968 WARN_ON(call != ftrace_file->event_call);
970 if (ftrace_trigger_soft_disabled(ftrace_file))
971 return;
973 local_save_flags(irq_flags);
974 pc = preempt_count();
976 dsize = __get_data_size(&tk->tp, regs);
977 size = sizeof(*entry) + tk->tp.size + dsize;
979 event = trace_event_buffer_lock_reserve(&buffer, ftrace_file,
980 call->event.type,
981 size, irq_flags, pc);
982 if (!event)
983 return;
985 entry = ring_buffer_event_data(event);
986 entry->func = (unsigned long)tk->rp.kp.addr;
987 entry->ret_ip = (unsigned long)ri->ret_addr;
988 store_trace_args(sizeof(*entry), &tk->tp, regs, (u8 *)&entry[1], dsize);
990 event_trigger_unlock_commit_regs(ftrace_file, buffer, event,
991 entry, irq_flags, pc, regs);
994 static __kprobes void
995 kretprobe_trace_func(struct trace_kprobe *tk, struct kretprobe_instance *ri,
996 struct pt_regs *regs)
998 struct event_file_link *link;
1000 list_for_each_entry_rcu(link, &tk->tp.files, list)
1001 __kretprobe_trace_func(tk, ri, regs, link->file);
1004 /* Event entry printers */
1005 static enum print_line_t
1006 print_kprobe_event(struct trace_iterator *iter, int flags,
1007 struct trace_event *event)
1009 struct kprobe_trace_entry_head *field;
1010 struct trace_seq *s = &iter->seq;
1011 struct trace_probe *tp;
1012 u8 *data;
1013 int i;
1015 field = (struct kprobe_trace_entry_head *)iter->ent;
1016 tp = container_of(event, struct trace_probe, call.event);
1018 if (!trace_seq_printf(s, "%s: (", ftrace_event_name(&tp->call)))
1019 goto partial;
1021 if (!seq_print_ip_sym(s, field->ip, flags | TRACE_ITER_SYM_OFFSET))
1022 goto partial;
1024 if (!trace_seq_puts(s, ")"))
1025 goto partial;
1027 data = (u8 *)&field[1];
1028 for (i = 0; i < tp->nr_args; i++)
1029 if (!tp->args[i].type->print(s, tp->args[i].name,
1030 data + tp->args[i].offset, field))
1031 goto partial;
1033 if (!trace_seq_puts(s, "\n"))
1034 goto partial;
1036 return TRACE_TYPE_HANDLED;
1037 partial:
1038 return TRACE_TYPE_PARTIAL_LINE;
1041 static enum print_line_t
1042 print_kretprobe_event(struct trace_iterator *iter, int flags,
1043 struct trace_event *event)
1045 struct kretprobe_trace_entry_head *field;
1046 struct trace_seq *s = &iter->seq;
1047 struct trace_probe *tp;
1048 u8 *data;
1049 int i;
1051 field = (struct kretprobe_trace_entry_head *)iter->ent;
1052 tp = container_of(event, struct trace_probe, call.event);
1054 if (!trace_seq_printf(s, "%s: (", ftrace_event_name(&tp->call)))
1055 goto partial;
1057 if (!seq_print_ip_sym(s, field->ret_ip, flags | TRACE_ITER_SYM_OFFSET))
1058 goto partial;
1060 if (!trace_seq_puts(s, " <- "))
1061 goto partial;
1063 if (!seq_print_ip_sym(s, field->func, flags & ~TRACE_ITER_SYM_OFFSET))
1064 goto partial;
1066 if (!trace_seq_puts(s, ")"))
1067 goto partial;
1069 data = (u8 *)&field[1];
1070 for (i = 0; i < tp->nr_args; i++)
1071 if (!tp->args[i].type->print(s, tp->args[i].name,
1072 data + tp->args[i].offset, field))
1073 goto partial;
1075 if (!trace_seq_puts(s, "\n"))
1076 goto partial;
1078 return TRACE_TYPE_HANDLED;
1079 partial:
1080 return TRACE_TYPE_PARTIAL_LINE;
1084 static int kprobe_event_define_fields(struct ftrace_event_call *event_call)
1086 int ret, i;
1087 struct kprobe_trace_entry_head field;
1088 struct trace_kprobe *tk = (struct trace_kprobe *)event_call->data;
1090 DEFINE_FIELD(unsigned long, ip, FIELD_STRING_IP, 0);
1091 /* Set argument names as fields */
1092 for (i = 0; i < tk->tp.nr_args; i++) {
1093 struct probe_arg *parg = &tk->tp.args[i];
1095 ret = trace_define_field(event_call, parg->type->fmttype,
1096 parg->name,
1097 sizeof(field) + parg->offset,
1098 parg->type->size,
1099 parg->type->is_signed,
1100 FILTER_OTHER);
1101 if (ret)
1102 return ret;
1104 return 0;
1107 static int kretprobe_event_define_fields(struct ftrace_event_call *event_call)
1109 int ret, i;
1110 struct kretprobe_trace_entry_head field;
1111 struct trace_kprobe *tk = (struct trace_kprobe *)event_call->data;
1113 DEFINE_FIELD(unsigned long, func, FIELD_STRING_FUNC, 0);
1114 DEFINE_FIELD(unsigned long, ret_ip, FIELD_STRING_RETIP, 0);
1115 /* Set argument names as fields */
1116 for (i = 0; i < tk->tp.nr_args; i++) {
1117 struct probe_arg *parg = &tk->tp.args[i];
1119 ret = trace_define_field(event_call, parg->type->fmttype,
1120 parg->name,
1121 sizeof(field) + parg->offset,
1122 parg->type->size,
1123 parg->type->is_signed,
1124 FILTER_OTHER);
1125 if (ret)
1126 return ret;
1128 return 0;
1131 #ifdef CONFIG_PERF_EVENTS
1133 /* Kprobe profile handler */
1134 static __kprobes void
1135 kprobe_perf_func(struct trace_kprobe *tk, struct pt_regs *regs)
1137 struct ftrace_event_call *call = &tk->tp.call;
1138 struct kprobe_trace_entry_head *entry;
1139 struct hlist_head *head;
1140 int size, __size, dsize;
1141 int rctx;
1143 head = this_cpu_ptr(call->perf_events);
1144 if (hlist_empty(head))
1145 return;
1147 dsize = __get_data_size(&tk->tp, regs);
1148 __size = sizeof(*entry) + tk->tp.size + dsize;
1149 size = ALIGN(__size + sizeof(u32), sizeof(u64));
1150 size -= sizeof(u32);
1152 entry = perf_trace_buf_prepare(size, call->event.type, regs, &rctx);
1153 if (!entry)
1154 return;
1156 entry->ip = (unsigned long)tk->rp.kp.addr;
1157 memset(&entry[1], 0, dsize);
1158 store_trace_args(sizeof(*entry), &tk->tp, regs, (u8 *)&entry[1], dsize);
1159 perf_trace_buf_submit(entry, size, rctx, 0, 1, regs, head, NULL);
1162 /* Kretprobe profile handler */
1163 static __kprobes void
1164 kretprobe_perf_func(struct trace_kprobe *tk, struct kretprobe_instance *ri,
1165 struct pt_regs *regs)
1167 struct ftrace_event_call *call = &tk->tp.call;
1168 struct kretprobe_trace_entry_head *entry;
1169 struct hlist_head *head;
1170 int size, __size, dsize;
1171 int rctx;
1173 head = this_cpu_ptr(call->perf_events);
1174 if (hlist_empty(head))
1175 return;
1177 dsize = __get_data_size(&tk->tp, regs);
1178 __size = sizeof(*entry) + tk->tp.size + dsize;
1179 size = ALIGN(__size + sizeof(u32), sizeof(u64));
1180 size -= sizeof(u32);
1182 entry = perf_trace_buf_prepare(size, call->event.type, regs, &rctx);
1183 if (!entry)
1184 return;
1186 entry->func = (unsigned long)tk->rp.kp.addr;
1187 entry->ret_ip = (unsigned long)ri->ret_addr;
1188 store_trace_args(sizeof(*entry), &tk->tp, regs, (u8 *)&entry[1], dsize);
1189 perf_trace_buf_submit(entry, size, rctx, 0, 1, regs, head, NULL);
1191 #endif /* CONFIG_PERF_EVENTS */
1194 * called by perf_trace_init() or __ftrace_set_clr_event() under event_mutex.
1196 * kprobe_trace_self_tests_init() does enable_trace_probe/disable_trace_probe
1197 * lockless, but we can't race with this __init function.
1199 static __kprobes
1200 int kprobe_register(struct ftrace_event_call *event,
1201 enum trace_reg type, void *data)
1203 struct trace_kprobe *tk = (struct trace_kprobe *)event->data;
1204 struct ftrace_event_file *file = data;
1206 switch (type) {
1207 case TRACE_REG_REGISTER:
1208 return enable_trace_kprobe(tk, file);
1209 case TRACE_REG_UNREGISTER:
1210 return disable_trace_kprobe(tk, file);
1212 #ifdef CONFIG_PERF_EVENTS
1213 case TRACE_REG_PERF_REGISTER:
1214 return enable_trace_kprobe(tk, NULL);
1215 case TRACE_REG_PERF_UNREGISTER:
1216 return disable_trace_kprobe(tk, NULL);
1217 case TRACE_REG_PERF_OPEN:
1218 case TRACE_REG_PERF_CLOSE:
1219 case TRACE_REG_PERF_ADD:
1220 case TRACE_REG_PERF_DEL:
1221 return 0;
1222 #endif
1224 return 0;
1227 static __kprobes
1228 int kprobe_dispatcher(struct kprobe *kp, struct pt_regs *regs)
1230 struct trace_kprobe *tk = container_of(kp, struct trace_kprobe, rp.kp);
1232 tk->nhit++;
1234 if (tk->tp.flags & TP_FLAG_TRACE)
1235 kprobe_trace_func(tk, regs);
1236 #ifdef CONFIG_PERF_EVENTS
1237 if (tk->tp.flags & TP_FLAG_PROFILE)
1238 kprobe_perf_func(tk, regs);
1239 #endif
1240 return 0; /* We don't tweek kernel, so just return 0 */
1243 static __kprobes
1244 int kretprobe_dispatcher(struct kretprobe_instance *ri, struct pt_regs *regs)
1246 struct trace_kprobe *tk = container_of(ri->rp, struct trace_kprobe, rp);
1248 tk->nhit++;
1250 if (tk->tp.flags & TP_FLAG_TRACE)
1251 kretprobe_trace_func(tk, ri, regs);
1252 #ifdef CONFIG_PERF_EVENTS
1253 if (tk->tp.flags & TP_FLAG_PROFILE)
1254 kretprobe_perf_func(tk, ri, regs);
1255 #endif
1256 return 0; /* We don't tweek kernel, so just return 0 */
1259 static struct trace_event_functions kretprobe_funcs = {
1260 .trace = print_kretprobe_event
1263 static struct trace_event_functions kprobe_funcs = {
1264 .trace = print_kprobe_event
1267 static int register_kprobe_event(struct trace_kprobe *tk)
1269 struct ftrace_event_call *call = &tk->tp.call;
1270 int ret;
1272 /* Initialize ftrace_event_call */
1273 INIT_LIST_HEAD(&call->class->fields);
1274 if (trace_kprobe_is_return(tk)) {
1275 call->event.funcs = &kretprobe_funcs;
1276 call->class->define_fields = kretprobe_event_define_fields;
1277 } else {
1278 call->event.funcs = &kprobe_funcs;
1279 call->class->define_fields = kprobe_event_define_fields;
1281 if (set_print_fmt(&tk->tp, trace_kprobe_is_return(tk)) < 0)
1282 return -ENOMEM;
1283 ret = register_ftrace_event(&call->event);
1284 if (!ret) {
1285 kfree(call->print_fmt);
1286 return -ENODEV;
1288 call->flags = 0;
1289 call->class->reg = kprobe_register;
1290 call->data = tk;
1291 ret = trace_add_event_call(call);
1292 if (ret) {
1293 pr_info("Failed to register kprobe event: %s\n",
1294 ftrace_event_name(call));
1295 kfree(call->print_fmt);
1296 unregister_ftrace_event(&call->event);
1298 return ret;
1301 static int unregister_kprobe_event(struct trace_kprobe *tk)
1303 int ret;
1305 /* tp->event is unregistered in trace_remove_event_call() */
1306 ret = trace_remove_event_call(&tk->tp.call);
1307 if (!ret)
1308 kfree(tk->tp.call.print_fmt);
1309 return ret;
1312 /* Make a debugfs interface for controlling probe points */
1313 static __init int init_kprobe_trace(void)
1315 struct dentry *d_tracer;
1316 struct dentry *entry;
1318 if (register_module_notifier(&trace_kprobe_module_nb))
1319 return -EINVAL;
1321 d_tracer = tracing_init_dentry();
1322 if (!d_tracer)
1323 return 0;
1325 entry = debugfs_create_file("kprobe_events", 0644, d_tracer,
1326 NULL, &kprobe_events_ops);
1328 /* Event list interface */
1329 if (!entry)
1330 pr_warning("Could not create debugfs "
1331 "'kprobe_events' entry\n");
1333 /* Profile interface */
1334 entry = debugfs_create_file("kprobe_profile", 0444, d_tracer,
1335 NULL, &kprobe_profile_ops);
1337 if (!entry)
1338 pr_warning("Could not create debugfs "
1339 "'kprobe_profile' entry\n");
1340 return 0;
1342 fs_initcall(init_kprobe_trace);
1345 #ifdef CONFIG_FTRACE_STARTUP_TEST
1348 * The "__used" keeps gcc from removing the function symbol
1349 * from the kallsyms table.
1351 static __used int kprobe_trace_selftest_target(int a1, int a2, int a3,
1352 int a4, int a5, int a6)
1354 return a1 + a2 + a3 + a4 + a5 + a6;
1357 static struct ftrace_event_file *
1358 find_trace_probe_file(struct trace_kprobe *tk, struct trace_array *tr)
1360 struct ftrace_event_file *file;
1362 list_for_each_entry(file, &tr->events, list)
1363 if (file->event_call == &tk->tp.call)
1364 return file;
1366 return NULL;
1370 * Nobody but us can call enable_trace_kprobe/disable_trace_kprobe at this
1371 * stage, we can do this lockless.
1373 static __init int kprobe_trace_self_tests_init(void)
1375 int ret, warn = 0;
1376 int (*target)(int, int, int, int, int, int);
1377 struct trace_kprobe *tk;
1378 struct ftrace_event_file *file;
1380 target = kprobe_trace_selftest_target;
1382 pr_info("Testing kprobe tracing: ");
1384 ret = traceprobe_command("p:testprobe kprobe_trace_selftest_target "
1385 "$stack $stack0 +0($stack)",
1386 create_trace_kprobe);
1387 if (WARN_ON_ONCE(ret)) {
1388 pr_warn("error on probing function entry.\n");
1389 warn++;
1390 } else {
1391 /* Enable trace point */
1392 tk = find_trace_kprobe("testprobe", KPROBE_EVENT_SYSTEM);
1393 if (WARN_ON_ONCE(tk == NULL)) {
1394 pr_warn("error on getting new probe.\n");
1395 warn++;
1396 } else {
1397 file = find_trace_probe_file(tk, top_trace_array());
1398 if (WARN_ON_ONCE(file == NULL)) {
1399 pr_warn("error on getting probe file.\n");
1400 warn++;
1401 } else
1402 enable_trace_kprobe(tk, file);
1406 ret = traceprobe_command("r:testprobe2 kprobe_trace_selftest_target "
1407 "$retval", create_trace_kprobe);
1408 if (WARN_ON_ONCE(ret)) {
1409 pr_warn("error on probing function return.\n");
1410 warn++;
1411 } else {
1412 /* Enable trace point */
1413 tk = find_trace_kprobe("testprobe2", KPROBE_EVENT_SYSTEM);
1414 if (WARN_ON_ONCE(tk == NULL)) {
1415 pr_warn("error on getting 2nd new probe.\n");
1416 warn++;
1417 } else {
1418 file = find_trace_probe_file(tk, top_trace_array());
1419 if (WARN_ON_ONCE(file == NULL)) {
1420 pr_warn("error on getting probe file.\n");
1421 warn++;
1422 } else
1423 enable_trace_kprobe(tk, file);
1427 if (warn)
1428 goto end;
1430 ret = target(1, 2, 3, 4, 5, 6);
1432 /* Disable trace points before removing it */
1433 tk = find_trace_kprobe("testprobe", KPROBE_EVENT_SYSTEM);
1434 if (WARN_ON_ONCE(tk == NULL)) {
1435 pr_warn("error on getting test probe.\n");
1436 warn++;
1437 } else {
1438 file = find_trace_probe_file(tk, top_trace_array());
1439 if (WARN_ON_ONCE(file == NULL)) {
1440 pr_warn("error on getting probe file.\n");
1441 warn++;
1442 } else
1443 disable_trace_kprobe(tk, file);
1446 tk = find_trace_kprobe("testprobe2", KPROBE_EVENT_SYSTEM);
1447 if (WARN_ON_ONCE(tk == NULL)) {
1448 pr_warn("error on getting 2nd test probe.\n");
1449 warn++;
1450 } else {
1451 file = find_trace_probe_file(tk, top_trace_array());
1452 if (WARN_ON_ONCE(file == NULL)) {
1453 pr_warn("error on getting probe file.\n");
1454 warn++;
1455 } else
1456 disable_trace_kprobe(tk, file);
1459 ret = traceprobe_command("-:testprobe", create_trace_kprobe);
1460 if (WARN_ON_ONCE(ret)) {
1461 pr_warn("error on deleting a probe.\n");
1462 warn++;
1465 ret = traceprobe_command("-:testprobe2", create_trace_kprobe);
1466 if (WARN_ON_ONCE(ret)) {
1467 pr_warn("error on deleting a probe.\n");
1468 warn++;
1471 end:
1472 release_all_trace_kprobes();
1473 if (warn)
1474 pr_cont("NG: Some tests are failed. Please check them.\n");
1475 else
1476 pr_cont("OK\n");
1477 return 0;
1480 late_initcall(kprobe_trace_self_tests_init);
1482 #endif