?  search:
summary | log | graphiclog1 | graphiclog2 | commit | commitdiff | tree | refs | edit | fork
blame | history | raw | HEAD
Linux 4.16-rc3
[cris-mirror.git] / kernel / trace / trace_kprobe.c
blob1fad24acd444581d8642e162c1c9ee441f4ccb52
1 /*
2 * Kprobes-based tracing events
3 *
4 * Created by Masami Hiramatsu <mhiramat@redhat.com>
5 *
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.
9 *
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.
14 *
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
18 */
19 #define pr_fmt(fmt) "trace_kprobe: " fmt
20
21 #include <linux/module.h>
22 #include <linux/uaccess.h>
23 #include <linux/rculist.h>
24 #include <linux/error-injection.h>
25
26 #include "trace_probe.h"
27
28 #define KPROBE_EVENT_SYSTEM "kprobes"
29 #define KRETPROBE_MAXACTIVE_MAX 4096
30
31 /**
32 * Kprobe event core functions
33 */
34 struct trace_kprobe {
35 struct list_head list;
36 struct kretprobe rp; /* Use rp.kp for kprobe use */
37 unsigned long __percpu *nhit;
38 const char *symbol; /* symbol name */
39 struct trace_probe tp;
40 };
41
42 #define SIZEOF_TRACE_KPROBE(n) \
43 (offsetof(struct trace_kprobe, tp.args) + \
44 (sizeof(struct probe_arg) * (n)))
45
46 static nokprobe_inline bool trace_kprobe_is_return(struct trace_kprobe *tk)
47 {
48 return tk->rp.handler != NULL;
49 }
50
51 static nokprobe_inline const char *trace_kprobe_symbol(struct trace_kprobe *tk)
52 {
53 return tk->symbol ? tk->symbol : "unknown";
54 }
55
56 static nokprobe_inline unsigned long trace_kprobe_offset(struct trace_kprobe *tk)
57 {
58 return tk->rp.kp.offset;
59 }
60
61 static nokprobe_inline bool trace_kprobe_has_gone(struct trace_kprobe *tk)
62 {
63 return !!(kprobe_gone(&tk->rp.kp));
64 }
65
66 static nokprobe_inline bool trace_kprobe_within_module(struct trace_kprobe *tk,
67 struct module *mod)
68 {
69 int len = strlen(mod->name);
70 const char *name = trace_kprobe_symbol(tk);
71 return strncmp(mod->name, name, len) == 0 && name[len] == ':';
72 }
73
74 static nokprobe_inline bool trace_kprobe_is_on_module(struct trace_kprobe *tk)
75 {
76 return !!strchr(trace_kprobe_symbol(tk), ':');
77 }
78
79 static nokprobe_inline unsigned long trace_kprobe_nhit(struct trace_kprobe *tk)
80 {
81 unsigned long nhit = 0;
82 int cpu;
83
84 for_each_possible_cpu(cpu)
85 nhit += *per_cpu_ptr(tk->nhit, cpu);
86
87 return nhit;
88 }
89
90 bool trace_kprobe_on_func_entry(struct trace_event_call *call)
91 {
92 struct trace_kprobe *tk = (struct trace_kprobe *)call->data;
93
94 return kprobe_on_func_entry(tk->rp.kp.addr,
95 tk->rp.kp.addr ? NULL : tk->rp.kp.symbol_name,
96 tk->rp.kp.addr ? 0 : tk->rp.kp.offset);
97 }
98
99 bool trace_kprobe_error_injectable(struct trace_event_call *call)
100 {
101 struct trace_kprobe *tk = (struct trace_kprobe *)call->data;
102 unsigned long addr;
103
104 if (tk->symbol) {
105 addr = (unsigned long)
106 kallsyms_lookup_name(trace_kprobe_symbol(tk));
107 addr += tk->rp.kp.offset;
108 } else {
109 addr = (unsigned long)tk->rp.kp.addr;
110 }
111 return within_error_injection_list(addr);
112 }
113
114 static int register_kprobe_event(struct trace_kprobe *tk);
115 static int unregister_kprobe_event(struct trace_kprobe *tk);
116
117 static DEFINE_MUTEX(probe_lock);
118 static LIST_HEAD(probe_list);
119
120 static int kprobe_dispatcher(struct kprobe *kp, struct pt_regs *regs);
121 static int kretprobe_dispatcher(struct kretprobe_instance *ri,
122 struct pt_regs *regs);
123
124 /* Memory fetching by symbol */
125 struct symbol_cache {
126 char *symbol;
127 long offset;
128 unsigned long addr;
129 };
130
131 unsigned long update_symbol_cache(struct symbol_cache *sc)
132 {
133 sc->addr = (unsigned long)kallsyms_lookup_name(sc->symbol);
134
135 if (sc->addr)
136 sc->addr += sc->offset;
137
138 return sc->addr;
139 }
140
141 void free_symbol_cache(struct symbol_cache *sc)
142 {
143 kfree(sc->symbol);
144 kfree(sc);
145 }
146
147 struct symbol_cache *alloc_symbol_cache(const char *sym, long offset)
148 {
149 struct symbol_cache *sc;
150
151 if (!sym || strlen(sym) == 0)
152 return NULL;
153
154 sc = kzalloc(sizeof(struct symbol_cache), GFP_KERNEL);
155 if (!sc)
156 return NULL;
157
158 sc->symbol = kstrdup(sym, GFP_KERNEL);
159 if (!sc->symbol) {
160 kfree(sc);
161 return NULL;
162 }
163 sc->offset = offset;
164 update_symbol_cache(sc);
165
166 return sc;
167 }
168
169 /*
170 * Kprobes-specific fetch functions
171 */
172 #define DEFINE_FETCH_stack(type) \
173 static void FETCH_FUNC_NAME(stack, type)(struct pt_regs *regs, \
174 void *offset, void *dest) \
175 { \
176 *(type *)dest = (type)regs_get_kernel_stack_nth(regs, \
177 (unsigned int)((unsigned long)offset)); \
178 } \
179 NOKPROBE_SYMBOL(FETCH_FUNC_NAME(stack, type));
180
181 DEFINE_BASIC_FETCH_FUNCS(stack)
182 /* No string on the stack entry */
183 #define fetch_stack_string NULL
184 #define fetch_stack_string_size NULL
185
186 #define DEFINE_FETCH_memory(type) \
187 static void FETCH_FUNC_NAME(memory, type)(struct pt_regs *regs, \
188 void *addr, void *dest) \
189 { \
190 type retval; \
191 if (probe_kernel_address(addr, retval)) \
192 *(type *)dest = 0; \
193 else \
194 *(type *)dest = retval; \
195 } \
196 NOKPROBE_SYMBOL(FETCH_FUNC_NAME(memory, type));
197
198 DEFINE_BASIC_FETCH_FUNCS(memory)
199 /*
200 * Fetch a null-terminated string. Caller MUST set *(u32 *)dest with max
201 * length and relative data location.
202 */
203 static void FETCH_FUNC_NAME(memory, string)(struct pt_regs *regs,
204 void *addr, void *dest)
205 {
206 int maxlen = get_rloc_len(*(u32 *)dest);
207 u8 *dst = get_rloc_data(dest);
208 long ret;
209
210 if (!maxlen)
211 return;
212
213 /*
214 * Try to get string again, since the string can be changed while
215 * probing.
216 */
217 ret = strncpy_from_unsafe(dst, addr, maxlen);
218
219 if (ret < 0) { /* Failed to fetch string */
220 dst[0] = '\0';
221 *(u32 *)dest = make_data_rloc(0, get_rloc_offs(*(u32 *)dest));
222 } else {
223 *(u32 *)dest = make_data_rloc(ret, get_rloc_offs(*(u32 *)dest));
224 }
225 }
226 NOKPROBE_SYMBOL(FETCH_FUNC_NAME(memory, string));
227
228 /* Return the length of string -- including null terminal byte */
229 static void FETCH_FUNC_NAME(memory, string_size)(struct pt_regs *regs,
230 void *addr, void *dest)
231 {
232 mm_segment_t old_fs;
233 int ret, len = 0;
234 u8 c;
235
236 old_fs = get_fs();
237 set_fs(KERNEL_DS);
238 pagefault_disable();
239
240 do {
241 ret = __copy_from_user_inatomic(&c, (u8 *)addr + len, 1);
242 len++;
243 } while (c && ret == 0 && len < MAX_STRING_SIZE);
244
245 pagefault_enable();
246 set_fs(old_fs);
247
248 if (ret < 0) /* Failed to check the length */
249 *(u32 *)dest = 0;
250 else
251 *(u32 *)dest = len;
252 }
253 NOKPROBE_SYMBOL(FETCH_FUNC_NAME(memory, string_size));
254
255 #define DEFINE_FETCH_symbol(type) \
256 void FETCH_FUNC_NAME(symbol, type)(struct pt_regs *regs, void *data, void *dest)\
257 { \
258 struct symbol_cache *sc = data; \
259 if (sc->addr) \
260 fetch_memory_##type(regs, (void *)sc->addr, dest); \
261 else \
262 *(type *)dest = 0; \
263 } \
264 NOKPROBE_SYMBOL(FETCH_FUNC_NAME(symbol, type));
265
266 DEFINE_BASIC_FETCH_FUNCS(symbol)
267 DEFINE_FETCH_symbol(string)
268 DEFINE_FETCH_symbol(string_size)
269
270 /* kprobes don't support file_offset fetch methods */
271 #define fetch_file_offset_u8 NULL
272 #define fetch_file_offset_u16 NULL
273 #define fetch_file_offset_u32 NULL
274 #define fetch_file_offset_u64 NULL
275 #define fetch_file_offset_string NULL
276 #define fetch_file_offset_string_size NULL
277
278 /* Fetch type information table */
279 static const struct fetch_type kprobes_fetch_type_table[] = {
280 /* Special types */
281 [FETCH_TYPE_STRING] = __ASSIGN_FETCH_TYPE("string", string, string,
282 sizeof(u32), 1, "__data_loc char[]"),
283 [FETCH_TYPE_STRSIZE] = __ASSIGN_FETCH_TYPE("string_size", u32,
284 string_size, sizeof(u32), 0, "u32"),
285 /* Basic types */
286 ASSIGN_FETCH_TYPE(u8, u8, 0),
287 ASSIGN_FETCH_TYPE(u16, u16, 0),
288 ASSIGN_FETCH_TYPE(u32, u32, 0),
289 ASSIGN_FETCH_TYPE(u64, u64, 0),
290 ASSIGN_FETCH_TYPE(s8, u8, 1),
291 ASSIGN_FETCH_TYPE(s16, u16, 1),
292 ASSIGN_FETCH_TYPE(s32, u32, 1),
293 ASSIGN_FETCH_TYPE(s64, u64, 1),
294 ASSIGN_FETCH_TYPE_ALIAS(x8, u8, u8, 0),
295 ASSIGN_FETCH_TYPE_ALIAS(x16, u16, u16, 0),
296 ASSIGN_FETCH_TYPE_ALIAS(x32, u32, u32, 0),
297 ASSIGN_FETCH_TYPE_ALIAS(x64, u64, u64, 0),
298
299 ASSIGN_FETCH_TYPE_END
300 };
301
302 /*
303 * Allocate new trace_probe and initialize it (including kprobes).
304 */
305 static struct trace_kprobe *alloc_trace_kprobe(const char *group,
306 const char *event,
307 void *addr,
308 const char *symbol,
309 unsigned long offs,
310 int maxactive,
311 int nargs, bool is_return)
312 {
313 struct trace_kprobe *tk;
314 int ret = -ENOMEM;
315
316 tk = kzalloc(SIZEOF_TRACE_KPROBE(nargs), GFP_KERNEL);
317 if (!tk)
318 return ERR_PTR(ret);
319
320 tk->nhit = alloc_percpu(unsigned long);
321 if (!tk->nhit)
322 goto error;
323
324 if (symbol) {
325 tk->symbol = kstrdup(symbol, GFP_KERNEL);
326 if (!tk->symbol)
327 goto error;
328 tk->rp.kp.symbol_name = tk->symbol;
329 tk->rp.kp.offset = offs;
330 } else
331 tk->rp.kp.addr = addr;
332
333 if (is_return)
334 tk->rp.handler = kretprobe_dispatcher;
335 else
336 tk->rp.kp.pre_handler = kprobe_dispatcher;
337
338 tk->rp.maxactive = maxactive;
339
340 if (!event || !is_good_name(event)) {
341 ret = -EINVAL;
342 goto error;
343 }
344
345 tk->tp.call.class = &tk->tp.class;
346 tk->tp.call.name = kstrdup(event, GFP_KERNEL);
347 if (!tk->tp.call.name)
348 goto error;
349
350 if (!group || !is_good_name(group)) {
351 ret = -EINVAL;
352 goto error;
353 }
354
355 tk->tp.class.system = kstrdup(group, GFP_KERNEL);
356 if (!tk->tp.class.system)
357 goto error;
358
359 INIT_LIST_HEAD(&tk->list);
360 INIT_LIST_HEAD(&tk->tp.files);
361 return tk;
362 error:
363 kfree(tk->tp.call.name);
364 kfree(tk->symbol);
365 free_percpu(tk->nhit);
366 kfree(tk);
367 return ERR_PTR(ret);
368 }
369
370 static void free_trace_kprobe(struct trace_kprobe *tk)
371 {
372 int i;
373
374 for (i = 0; i < tk->tp.nr_args; i++)
375 traceprobe_free_probe_arg(&tk->tp.args[i]);
376
377 kfree(tk->tp.call.class->system);
378 kfree(tk->tp.call.name);
379 kfree(tk->symbol);
380 free_percpu(tk->nhit);
381 kfree(tk);
382 }
383
384 static struct trace_kprobe *find_trace_kprobe(const char *event,
385 const char *group)
386 {
387 struct trace_kprobe *tk;
388
389 list_for_each_entry(tk, &probe_list, list)
390 if (strcmp(trace_event_name(&tk->tp.call), event) == 0 &&
391 strcmp(tk->tp.call.class->system, group) == 0)
392 return tk;
393 return NULL;
394 }
395
396 /*
397 * Enable trace_probe
398 * if the file is NULL, enable "perf" handler, or enable "trace" handler.
399 */
400 static int
401 enable_trace_kprobe(struct trace_kprobe *tk, struct trace_event_file *file)
402 {
403 int ret = 0;
404
405 if (file) {
406 struct event_file_link *link;
407
408 link = kmalloc(sizeof(*link), GFP_KERNEL);
409 if (!link) {
410 ret = -ENOMEM;
411 goto out;
412 }
413
414 link->file = file;
415 list_add_tail_rcu(&link->list, &tk->tp.files);
416
417 tk->tp.flags |= TP_FLAG_TRACE;
418 } else
419 tk->tp.flags |= TP_FLAG_PROFILE;
420
421 if (trace_probe_is_registered(&tk->tp) && !trace_kprobe_has_gone(tk)) {
422 if (trace_kprobe_is_return(tk))
423 ret = enable_kretprobe(&tk->rp);
424 else
425 ret = enable_kprobe(&tk->rp.kp);
426 }
427 out:
428 return ret;
429 }
430
431 /*
432 * Disable trace_probe
433 * if the file is NULL, disable "perf" handler, or disable "trace" handler.
434 */
435 static int
436 disable_trace_kprobe(struct trace_kprobe *tk, struct trace_event_file *file)
437 {
438 struct event_file_link *link = NULL;
439 int wait = 0;
440 int ret = 0;
441
442 if (file) {
443 link = find_event_file_link(&tk->tp, file);
444 if (!link) {
445 ret = -EINVAL;
446 goto out;
447 }
448
449 list_del_rcu(&link->list);
450 wait = 1;
451 if (!list_empty(&tk->tp.files))
452 goto out;
453
454 tk->tp.flags &= ~TP_FLAG_TRACE;
455 } else
456 tk->tp.flags &= ~TP_FLAG_PROFILE;
457
458 if (!trace_probe_is_enabled(&tk->tp) && trace_probe_is_registered(&tk->tp)) {
459 if (trace_kprobe_is_return(tk))
460 disable_kretprobe(&tk->rp);
461 else
462 disable_kprobe(&tk->rp.kp);
463 wait = 1;
464 }
465 out:
466 if (wait) {
467 /*
468 * Synchronize with kprobe_trace_func/kretprobe_trace_func
469 * to ensure disabled (all running handlers are finished).
470 * This is not only for kfree(), but also the caller,
471 * trace_remove_event_call() supposes it for releasing
472 * event_call related objects, which will be accessed in
473 * the kprobe_trace_func/kretprobe_trace_func.
474 */
475 synchronize_sched();
476 kfree(link); /* Ignored if link == NULL */
477 }
478
479 return ret;
480 }
481
482 /* Internal register function - just handle k*probes and flags */
483 static int __register_trace_kprobe(struct trace_kprobe *tk)
484 {
485 int i, ret;
486
487 if (trace_probe_is_registered(&tk->tp))
488 return -EINVAL;
489
490 for (i = 0; i < tk->tp.nr_args; i++)
491 traceprobe_update_arg(&tk->tp.args[i]);
492
493 /* Set/clear disabled flag according to tp->flag */
494 if (trace_probe_is_enabled(&tk->tp))
495 tk->rp.kp.flags &= ~KPROBE_FLAG_DISABLED;
496 else
497 tk->rp.kp.flags |= KPROBE_FLAG_DISABLED;
498
499 if (trace_kprobe_is_return(tk))
500 ret = register_kretprobe(&tk->rp);
501 else
502 ret = register_kprobe(&tk->rp.kp);
503
504 if (ret == 0)
505 tk->tp.flags |= TP_FLAG_REGISTERED;
506 else {
507 pr_warn("Could not insert probe at %s+%lu: %d\n",
508 trace_kprobe_symbol(tk), trace_kprobe_offset(tk), ret);
509 if (ret == -ENOENT && trace_kprobe_is_on_module(tk)) {
510 pr_warn("This probe might be able to register after target module is loaded. Continue.\n");
511 ret = 0;
512 } else if (ret == -EILSEQ) {
513 pr_warn("Probing address(0x%p) is not an instruction boundary.\n",
514 tk->rp.kp.addr);
515 ret = -EINVAL;
516 }
517 }
518
519 return ret;
520 }
521
522 /* Internal unregister function - just handle k*probes and flags */
523 static void __unregister_trace_kprobe(struct trace_kprobe *tk)
524 {
525 if (trace_probe_is_registered(&tk->tp)) {
526 if (trace_kprobe_is_return(tk))
527 unregister_kretprobe(&tk->rp);
528 else
529 unregister_kprobe(&tk->rp.kp);
530 tk->tp.flags &= ~TP_FLAG_REGISTERED;
531 /* Cleanup kprobe for reuse */
532 if (tk->rp.kp.symbol_name)
533 tk->rp.kp.addr = NULL;
534 }
535 }
536
537 /* Unregister a trace_probe and probe_event: call with locking probe_lock */
538 static int unregister_trace_kprobe(struct trace_kprobe *tk)
539 {
540 /* Enabled event can not be unregistered */
541 if (trace_probe_is_enabled(&tk->tp))
542 return -EBUSY;
543
544 /* Will fail if probe is being used by ftrace or perf */
545 if (unregister_kprobe_event(tk))
546 return -EBUSY;
547
548 __unregister_trace_kprobe(tk);
549 list_del(&tk->list);
550
551 return 0;
552 }
553
554 /* Register a trace_probe and probe_event */
555 static int register_trace_kprobe(struct trace_kprobe *tk)
556 {
557 struct trace_kprobe *old_tk;
558 int ret;
559
560 mutex_lock(&probe_lock);
561
562 /* Delete old (same name) event if exist */
563 old_tk = find_trace_kprobe(trace_event_name(&tk->tp.call),
564 tk->tp.call.class->system);
565 if (old_tk) {
566 ret = unregister_trace_kprobe(old_tk);
567 if (ret < 0)
568 goto end;
569 free_trace_kprobe(old_tk);
570 }
571
572 /* Register new event */
573 ret = register_kprobe_event(tk);
574 if (ret) {
575 pr_warn("Failed to register probe event(%d)\n", ret);
576 goto end;
577 }
578
579 /* Register k*probe */
580 ret = __register_trace_kprobe(tk);
581 if (ret < 0)
582 unregister_kprobe_event(tk);
583 else
584 list_add_tail(&tk->list, &probe_list);
585
586 end:
587 mutex_unlock(&probe_lock);
588 return ret;
589 }
590
591 /* Module notifier call back, checking event on the module */
592 static int trace_kprobe_module_callback(struct notifier_block *nb,
593 unsigned long val, void *data)
594 {
595 struct module *mod = data;
596 struct trace_kprobe *tk;
597 int ret;
598
599 if (val != MODULE_STATE_COMING)
600 return NOTIFY_DONE;
601
602 /* Update probes on coming module */
603 mutex_lock(&probe_lock);
604 list_for_each_entry(tk, &probe_list, list) {
605 if (trace_kprobe_within_module(tk, mod)) {
606 /* Don't need to check busy - this should have gone. */
607 __unregister_trace_kprobe(tk);
608 ret = __register_trace_kprobe(tk);
609 if (ret)
610 pr_warn("Failed to re-register probe %s on %s: %d\n",
611 trace_event_name(&tk->tp.call),
612 mod->name, ret);
613 }
614 }
615 mutex_unlock(&probe_lock);
616
617 return NOTIFY_DONE;
618 }
619
620 static struct notifier_block trace_kprobe_module_nb = {
621 .notifier_call = trace_kprobe_module_callback,
622 .priority = 1 /* Invoked after kprobe module callback */
623 };
624
625 /* Convert certain expected symbols into '_' when generating event names */
626 static inline void sanitize_event_name(char *name)
627 {
628 while (*name++ != '\0')
629 if (*name == ':' || *name == '.')
630 *name = '_';
631 }
632
633 static int create_trace_kprobe(int argc, char **argv)
634 {
635 /*
636 * Argument syntax:
637 * - Add kprobe:
638 * p[:[GRP/]EVENT] [MOD:]KSYM[+OFFS]|KADDR [FETCHARGS]
639 * - Add kretprobe:
640 * r[MAXACTIVE][:[GRP/]EVENT] [MOD:]KSYM[+0] [FETCHARGS]
641 * Fetch args:
642 * $retval : fetch return value
643 * $stack : fetch stack address
644 * $stackN : fetch Nth of stack (N:0-)
645 * $comm : fetch current task comm
646 * @ADDR : fetch memory at ADDR (ADDR should be in kernel)
647 * @SYM[+|-offs] : fetch memory at SYM +|- offs (SYM is a data symbol)
648 * %REG : fetch register REG
649 * Dereferencing memory fetch:
650 * +|-offs(ARG) : fetch memory at ARG +|- offs address.
651 * Alias name of args:
652 * NAME=FETCHARG : set NAME as alias of FETCHARG.
653 * Type of args:
654 * FETCHARG:TYPE : use TYPE instead of unsigned long.
655 */
656 struct trace_kprobe *tk;
657 int i, ret = 0;
658 bool is_return = false, is_delete = false;
659 char *symbol = NULL, *event = NULL, *group = NULL;
660 int maxactive = 0;
661 char *arg;
662 unsigned long offset = 0;
663 void *addr = NULL;
664 char buf[MAX_EVENT_NAME_LEN];
665
666 /* argc must be >= 1 */
667 if (argv[0][0] == 'p')
668 is_return = false;
669 else if (argv[0][0] == 'r')
670 is_return = true;
671 else if (argv[0][0] == '-')
672 is_delete = true;
673 else {
674 pr_info("Probe definition must be started with 'p', 'r' or"
675 " '-'.\n");
676 return -EINVAL;
677 }
678
679 event = strchr(&argv[0][1], ':');
680 if (event) {
681 event[0] = '\0';
682 event++;
683 }
684 if (is_return && isdigit(argv[0][1])) {
685 ret = kstrtouint(&argv[0][1], 0, &maxactive);
686 if (ret) {
687 pr_info("Failed to parse maxactive.\n");
688 return ret;
689 }
690 /* kretprobes instances are iterated over via a list. The
691 * maximum should stay reasonable.
692 */
693 if (maxactive > KRETPROBE_MAXACTIVE_MAX) {
694 pr_info("Maxactive is too big (%d > %d).\n",
695 maxactive, KRETPROBE_MAXACTIVE_MAX);
696 return -E2BIG;
697 }
698 }
699
700 if (event) {
701 if (strchr(event, '/')) {
702 group = event;
703 event = strchr(group, '/') + 1;
704 event[-1] = '\0';
705 if (strlen(group) == 0) {
706 pr_info("Group name is not specified\n");
707 return -EINVAL;
708 }
709 }
710 if (strlen(event) == 0) {
711 pr_info("Event name is not specified\n");
712 return -EINVAL;
713 }
714 }
715 if (!group)
716 group = KPROBE_EVENT_SYSTEM;
717
718 if (is_delete) {
719 if (!event) {
720 pr_info("Delete command needs an event name.\n");
721 return -EINVAL;
722 }
723 mutex_lock(&probe_lock);
724 tk = find_trace_kprobe(event, group);
725 if (!tk) {
726 mutex_unlock(&probe_lock);
727 pr_info("Event %s/%s doesn't exist.\n", group, event);
728 return -ENOENT;
729 }
730 /* delete an event */
731 ret = unregister_trace_kprobe(tk);
732 if (ret == 0)
733 free_trace_kprobe(tk);
734 mutex_unlock(&probe_lock);
735 return ret;
736 }
737
738 if (argc < 2) {
739 pr_info("Probe point is not specified.\n");
740 return -EINVAL;
741 }
742
743 /* try to parse an address. if that fails, try to read the
744 * input as a symbol. */
745 if (kstrtoul(argv[1], 0, (unsigned long *)&addr)) {
746 /* a symbol specified */
747 symbol = argv[1];
748 /* TODO: support .init module functions */
749 ret = traceprobe_split_symbol_offset(symbol, &offset);
750 if (ret) {
751 pr_info("Failed to parse either an address or a symbol.\n");
752 return ret;
753 }
754 if (offset && is_return &&
755 !kprobe_on_func_entry(NULL, symbol, offset)) {
756 pr_info("Given offset is not valid for return probe.\n");
757 return -EINVAL;
758 }
759 }
760 argc -= 2; argv += 2;
761
762 /* setup a probe */
763 if (!event) {
764 /* Make a new event name */
765 if (symbol)
766 snprintf(buf, MAX_EVENT_NAME_LEN, "%c_%s_%ld",
767 is_return ? 'r' : 'p', symbol, offset);
768 else
769 snprintf(buf, MAX_EVENT_NAME_LEN, "%c_0x%p",
770 is_return ? 'r' : 'p', addr);
771 sanitize_event_name(buf);
772 event = buf;
773 }
774 tk = alloc_trace_kprobe(group, event, addr, symbol, offset, maxactive,
775 argc, is_return);
776 if (IS_ERR(tk)) {
777 pr_info("Failed to allocate trace_probe.(%d)\n",
778 (int)PTR_ERR(tk));
779 return PTR_ERR(tk);
780 }
781
782 /* parse arguments */
783 ret = 0;
784 for (i = 0; i < argc && i < MAX_TRACE_ARGS; i++) {
785 struct probe_arg *parg = &tk->tp.args[i];
786
787 /* Increment count for freeing args in error case */
788 tk->tp.nr_args++;
789
790 /* Parse argument name */
791 arg = strchr(argv[i], '=');
792 if (arg) {
793 *arg++ = '\0';
794 parg->name = kstrdup(argv[i], GFP_KERNEL);
795 } else {
796 arg = argv[i];
797 /* If argument name is omitted, set "argN" */
798 snprintf(buf, MAX_EVENT_NAME_LEN, "arg%d", i + 1);
799 parg->name = kstrdup(buf, GFP_KERNEL);
800 }
801
802 if (!parg->name) {
803 pr_info("Failed to allocate argument[%d] name.\n", i);
804 ret = -ENOMEM;
805 goto error;
806 }
807
808 if (!is_good_name(parg->name)) {
809 pr_info("Invalid argument[%d] name: %s\n",
810 i, parg->name);
811 ret = -EINVAL;
812 goto error;
813 }
814
815 if (traceprobe_conflict_field_name(parg->name,
816 tk->tp.args, i)) {
817 pr_info("Argument[%d] name '%s' conflicts with "
818 "another field.\n", i, argv[i]);
819 ret = -EINVAL;
820 goto error;
821 }
822
823 /* Parse fetch argument */
824 ret = traceprobe_parse_probe_arg(arg, &tk->tp.size, parg,
825 is_return, true,
826 kprobes_fetch_type_table);
827 if (ret) {
828 pr_info("Parse error at argument[%d]. (%d)\n", i, ret);
829 goto error;
830 }
831 }
832
833 ret = register_trace_kprobe(tk);
834 if (ret)
835 goto error;
836 return 0;
837
838 error:
839 free_trace_kprobe(tk);
840 return ret;
841 }
842
843 static int release_all_trace_kprobes(void)
844 {
845 struct trace_kprobe *tk;
846 int ret = 0;
847
848 mutex_lock(&probe_lock);
849 /* Ensure no probe is in use. */
850 list_for_each_entry(tk, &probe_list, list)
851 if (trace_probe_is_enabled(&tk->tp)) {
852 ret = -EBUSY;
853 goto end;
854 }
855 /* TODO: Use batch unregistration */
856 while (!list_empty(&probe_list)) {
857 tk = list_entry(probe_list.next, struct trace_kprobe, list);
858 ret = unregister_trace_kprobe(tk);
859 if (ret)
860 goto end;
861 free_trace_kprobe(tk);
862 }
863
864 end:
865 mutex_unlock(&probe_lock);
866
867 return ret;
868 }
869
870 /* Probes listing interfaces */
871 static void *probes_seq_start(struct seq_file *m, loff_t *pos)
872 {
873 mutex_lock(&probe_lock);
874 return seq_list_start(&probe_list, *pos);
875 }
876
877 static void *probes_seq_next(struct seq_file *m, void *v, loff_t *pos)
878 {
879 return seq_list_next(v, &probe_list, pos);
880 }
881
882 static void probes_seq_stop(struct seq_file *m, void *v)
883 {
884 mutex_unlock(&probe_lock);
885 }
886
887 static int probes_seq_show(struct seq_file *m, void *v)
888 {
889 struct trace_kprobe *tk = v;
890 int i;
891
892 seq_putc(m, trace_kprobe_is_return(tk) ? 'r' : 'p');
893 seq_printf(m, ":%s/%s", tk->tp.call.class->system,
894 trace_event_name(&tk->tp.call));
895
896 if (!tk->symbol)
897 seq_printf(m, " 0x%p", tk->rp.kp.addr);
898 else if (tk->rp.kp.offset)
899 seq_printf(m, " %s+%u", trace_kprobe_symbol(tk),
900 tk->rp.kp.offset);
901 else
902 seq_printf(m, " %s", trace_kprobe_symbol(tk));
903
904 for (i = 0; i < tk->tp.nr_args; i++)
905 seq_printf(m, " %s=%s", tk->tp.args[i].name, tk->tp.args[i].comm);
906 seq_putc(m, '\n');
907
908 return 0;
909 }
910
911 static const struct seq_operations probes_seq_op = {
912 .start = probes_seq_start,
913 .next = probes_seq_next,
914 .stop = probes_seq_stop,
915 .show = probes_seq_show
916 };
917
918 static int probes_open(struct inode *inode, struct file *file)
919 {
920 int ret;
921
922 if ((file->f_mode & FMODE_WRITE) && (file->f_flags & O_TRUNC)) {
923 ret = release_all_trace_kprobes();
924 if (ret < 0)
925 return ret;
926 }
927
928 return seq_open(file, &probes_seq_op);
929 }
930
931 static ssize_t probes_write(struct file *file, const char __user *buffer,
932 size_t count, loff_t *ppos)
933 {
934 return trace_parse_run_command(file, buffer, count, ppos,
935 create_trace_kprobe);
936 }
937
938 static const struct file_operations kprobe_events_ops = {
939 .owner = THIS_MODULE,
940 .open = probes_open,
941 .read = seq_read,
942 .llseek = seq_lseek,
943 .release = seq_release,
944 .write = probes_write,
945 };
946
947 /* Probes profiling interfaces */
948 static int probes_profile_seq_show(struct seq_file *m, void *v)
949 {
950 struct trace_kprobe *tk = v;
951
952 seq_printf(m, " %-44s %15lu %15lu\n",
953 trace_event_name(&tk->tp.call),
954 trace_kprobe_nhit(tk),
955 tk->rp.kp.nmissed);
956
957 return 0;
958 }
959
960 static const struct seq_operations profile_seq_op = {
961 .start = probes_seq_start,
962 .next = probes_seq_next,
963 .stop = probes_seq_stop,
964 .show = probes_profile_seq_show
965 };
966
967 static int profile_open(struct inode *inode, struct file *file)
968 {
969 return seq_open(file, &profile_seq_op);
970 }
971
972 static const struct file_operations kprobe_profile_ops = {
973 .owner = THIS_MODULE,
974 .open = profile_open,
975 .read = seq_read,
976 .llseek = seq_lseek,
977 .release = seq_release,
978 };
979
980 /* Kprobe handler */
981 static nokprobe_inline void
982 __kprobe_trace_func(struct trace_kprobe *tk, struct pt_regs *regs,
983 struct trace_event_file *trace_file)
984 {
985 struct kprobe_trace_entry_head *entry;
986 struct ring_buffer_event *event;
987 struct ring_buffer *buffer;
988 int size, dsize, pc;
989 unsigned long irq_flags;
990 struct trace_event_call *call = &tk->tp.call;
991
992 WARN_ON(call != trace_file->event_call);
993
994 if (trace_trigger_soft_disabled(trace_file))
995 return;
996
997 local_save_flags(irq_flags);
998 pc = preempt_count();
999
1000 dsize = __get_data_size(&tk->tp, regs);
1001 size = sizeof(*entry) + tk->tp.size + dsize;
1002
1003 event = trace_event_buffer_lock_reserve(&buffer, trace_file,
1004 call->event.type,
1005 size, irq_flags, pc);
1006 if (!event)
1007 return;
1008
1009 entry = ring_buffer_event_data(event);
1010 entry->ip = (unsigned long)tk->rp.kp.addr;
1011 store_trace_args(sizeof(*entry), &tk->tp, regs, (u8 *)&entry[1], dsize);
1012
1013 event_trigger_unlock_commit_regs(trace_file, buffer, event,
1014 entry, irq_flags, pc, regs);
1015 }
1016
1017 static void
1018 kprobe_trace_func(struct trace_kprobe *tk, struct pt_regs *regs)
1019 {
1020 struct event_file_link *link;
1021
1022 list_for_each_entry_rcu(link, &tk->tp.files, list)
1023 __kprobe_trace_func(tk, regs, link->file);
1024 }
1025 NOKPROBE_SYMBOL(kprobe_trace_func);
1026
1027 /* Kretprobe handler */
1028 static nokprobe_inline void
1029 __kretprobe_trace_func(struct trace_kprobe *tk, struct kretprobe_instance *ri,
1030 struct pt_regs *regs,
1031 struct trace_event_file *trace_file)
1032 {
1033 struct kretprobe_trace_entry_head *entry;
1034 struct ring_buffer_event *event;
1035 struct ring_buffer *buffer;
1036 int size, pc, dsize;
1037 unsigned long irq_flags;
1038 struct trace_event_call *call = &tk->tp.call;
1039
1040 WARN_ON(call != trace_file->event_call);
1041
1042 if (trace_trigger_soft_disabled(trace_file))
1043 return;
1044
1045 local_save_flags(irq_flags);
1046 pc = preempt_count();
1047
1048 dsize = __get_data_size(&tk->tp, regs);
1049 size = sizeof(*entry) + tk->tp.size + dsize;
1050
1051 event = trace_event_buffer_lock_reserve(&buffer, trace_file,
1052 call->event.type,
1053 size, irq_flags, pc);
1054 if (!event)
1055 return;
1056
1057 entry = ring_buffer_event_data(event);
1058 entry->func = (unsigned long)tk->rp.kp.addr;
1059 entry->ret_ip = (unsigned long)ri->ret_addr;
1060 store_trace_args(sizeof(*entry), &tk->tp, regs, (u8 *)&entry[1], dsize);
1061
1062 event_trigger_unlock_commit_regs(trace_file, buffer, event,
1063 entry, irq_flags, pc, regs);
1064 }
1065
1066 static void
1067 kretprobe_trace_func(struct trace_kprobe *tk, struct kretprobe_instance *ri,
1068 struct pt_regs *regs)
1069 {
1070 struct event_file_link *link;
1071
1072 list_for_each_entry_rcu(link, &tk->tp.files, list)
1073 __kretprobe_trace_func(tk, ri, regs, link->file);
1074 }
1075 NOKPROBE_SYMBOL(kretprobe_trace_func);
1076
1077 /* Event entry printers */
1078 static enum print_line_t
1079 print_kprobe_event(struct trace_iterator *iter, int flags,
1080 struct trace_event *event)
1081 {
1082 struct kprobe_trace_entry_head *field;
1083 struct trace_seq *s = &iter->seq;
1084 struct trace_probe *tp;
1085 u8 *data;
1086 int i;
1087
1088 field = (struct kprobe_trace_entry_head *)iter->ent;
1089 tp = container_of(event, struct trace_probe, call.event);
1090
1091 trace_seq_printf(s, "%s: (", trace_event_name(&tp->call));
1092
1093 if (!seq_print_ip_sym(s, field->ip, flags | TRACE_ITER_SYM_OFFSET))
1094 goto out;
1095
1096 trace_seq_putc(s, ')');
1097
1098 data = (u8 *)&field[1];
1099 for (i = 0; i < tp->nr_args; i++)
1100 if (!tp->args[i].type->print(s, tp->args[i].name,
1101 data + tp->args[i].offset, field))
1102 goto out;
1103
1104 trace_seq_putc(s, '\n');
1105 out:
1106 return trace_handle_return(s);
1107 }
1108
1109 static enum print_line_t
1110 print_kretprobe_event(struct trace_iterator *iter, int flags,
1111 struct trace_event *event)
1112 {
1113 struct kretprobe_trace_entry_head *field;
1114 struct trace_seq *s = &iter->seq;
1115 struct trace_probe *tp;
1116 u8 *data;
1117 int i;
1118
1119 field = (struct kretprobe_trace_entry_head *)iter->ent;
1120 tp = container_of(event, struct trace_probe, call.event);
1121
1122 trace_seq_printf(s, "%s: (", trace_event_name(&tp->call));
1123
1124 if (!seq_print_ip_sym(s, field->ret_ip, flags | TRACE_ITER_SYM_OFFSET))
1125 goto out;
1126
1127 trace_seq_puts(s, " <- ");
1128
1129 if (!seq_print_ip_sym(s, field->func, flags & ~TRACE_ITER_SYM_OFFSET))
1130 goto out;
1131
1132 trace_seq_putc(s, ')');
1133
1134 data = (u8 *)&field[1];
1135 for (i = 0; i < tp->nr_args; i++)
1136 if (!tp->args[i].type->print(s, tp->args[i].name,
1137 data + tp->args[i].offset, field))
1138 goto out;
1139
1140 trace_seq_putc(s, '\n');
1141
1142 out:
1143 return trace_handle_return(s);
1144 }
1145
1146
1147 static int kprobe_event_define_fields(struct trace_event_call *event_call)
1148 {
1149 int ret, i;
1150 struct kprobe_trace_entry_head field;
1151 struct trace_kprobe *tk = (struct trace_kprobe *)event_call->data;
1152
1153 DEFINE_FIELD(unsigned long, ip, FIELD_STRING_IP, 0);
1154 /* Set argument names as fields */
1155 for (i = 0; i < tk->tp.nr_args; i++) {
1156 struct probe_arg *parg = &tk->tp.args[i];
1157
1158 ret = trace_define_field(event_call, parg->type->fmttype,
1159 parg->name,
1160 sizeof(field) + parg->offset,
1161 parg->type->size,
1162 parg->type->is_signed,
1163 FILTER_OTHER);
1164 if (ret)
1165 return ret;
1166 }
1167 return 0;
1168 }
1169
1170 static int kretprobe_event_define_fields(struct trace_event_call *event_call)
1171 {
1172 int ret, i;
1173 struct kretprobe_trace_entry_head field;
1174 struct trace_kprobe *tk = (struct trace_kprobe *)event_call->data;
1175
1176 DEFINE_FIELD(unsigned long, func, FIELD_STRING_FUNC, 0);
1177 DEFINE_FIELD(unsigned long, ret_ip, FIELD_STRING_RETIP, 0);
1178 /* Set argument names as fields */
1179 for (i = 0; i < tk->tp.nr_args; i++) {
1180 struct probe_arg *parg = &tk->tp.args[i];
1181
1182 ret = trace_define_field(event_call, parg->type->fmttype,
1183 parg->name,
1184 sizeof(field) + parg->offset,
1185 parg->type->size,
1186 parg->type->is_signed,
1187 FILTER_OTHER);
1188 if (ret)
1189 return ret;
1190 }
1191 return 0;
1192 }
1193
1194 #ifdef CONFIG_PERF_EVENTS
1195
1196 /* Kprobe profile handler */
1197 static int
1198 kprobe_perf_func(struct trace_kprobe *tk, struct pt_regs *regs)
1199 {
1200 struct trace_event_call *call = &tk->tp.call;
1201 struct kprobe_trace_entry_head *entry;
1202 struct hlist_head *head;
1203 int size, __size, dsize;
1204 int rctx;
1205
1206 if (bpf_prog_array_valid(call)) {
1207 unsigned long orig_ip = instruction_pointer(regs);
1208 int ret;
1209
1210 ret = trace_call_bpf(call, regs);
1211
1212 /*
1213 * We need to check and see if we modified the pc of the
1214 * pt_regs, and if so clear the kprobe and return 1 so that we
1215 * don't do the single stepping.
1216 * The ftrace kprobe handler leaves it up to us to re-enable
1217 * preemption here before returning if we've modified the ip.
1218 */
1219 if (orig_ip != instruction_pointer(regs)) {
1220 reset_current_kprobe();
1221 preempt_enable_no_resched();
1222 return 1;
1223 }
1224 if (!ret)
1225 return 0;
1226 }
1227
1228 head = this_cpu_ptr(call->perf_events);
1229 if (hlist_empty(head))
1230 return 0;
1231
1232 dsize = __get_data_size(&tk->tp, regs);
1233 __size = sizeof(*entry) + tk->tp.size + dsize;
1234 size = ALIGN(__size + sizeof(u32), sizeof(u64));
1235 size -= sizeof(u32);
1236
1237 entry = perf_trace_buf_alloc(size, NULL, &rctx);
1238 if (!entry)
1239 return 0;
1240
1241 entry->ip = (unsigned long)tk->rp.kp.addr;
1242 memset(&entry[1], 0, dsize);
1243 store_trace_args(sizeof(*entry), &tk->tp, regs, (u8 *)&entry[1], dsize);
1244 perf_trace_buf_submit(entry, size, rctx, call->event.type, 1, regs,
1245 head, NULL);
1246 return 0;
1247 }
1248 NOKPROBE_SYMBOL(kprobe_perf_func);
1249
1250 /* Kretprobe profile handler */
1251 static void
1252 kretprobe_perf_func(struct trace_kprobe *tk, struct kretprobe_instance *ri,
1253 struct pt_regs *regs)
1254 {
1255 struct trace_event_call *call = &tk->tp.call;
1256 struct kretprobe_trace_entry_head *entry;
1257 struct hlist_head *head;
1258 int size, __size, dsize;
1259 int rctx;
1260
1261 if (bpf_prog_array_valid(call) && !trace_call_bpf(call, regs))
1262 return;
1263
1264 head = this_cpu_ptr(call->perf_events);
1265 if (hlist_empty(head))
1266 return;
1267
1268 dsize = __get_data_size(&tk->tp, regs);
1269 __size = sizeof(*entry) + tk->tp.size + dsize;
1270 size = ALIGN(__size + sizeof(u32), sizeof(u64));
1271 size -= sizeof(u32);
1272
1273 entry = perf_trace_buf_alloc(size, NULL, &rctx);
1274 if (!entry)
1275 return;
1276
1277 entry->func = (unsigned long)tk->rp.kp.addr;
1278 entry->ret_ip = (unsigned long)ri->ret_addr;
1279 store_trace_args(sizeof(*entry), &tk->tp, regs, (u8 *)&entry[1], dsize);
1280 perf_trace_buf_submit(entry, size, rctx, call->event.type, 1, regs,
1281 head, NULL);
1282 }
1283 NOKPROBE_SYMBOL(kretprobe_perf_func);
1284 #endif /* CONFIG_PERF_EVENTS */
1285
1286 /*
1287 * called by perf_trace_init() or __ftrace_set_clr_event() under event_mutex.
1288 *
1289 * kprobe_trace_self_tests_init() does enable_trace_probe/disable_trace_probe
1290 * lockless, but we can't race with this __init function.
1291 */
1292 static int kprobe_register(struct trace_event_call *event,
1293 enum trace_reg type, void *data)
1294 {
1295 struct trace_kprobe *tk = (struct trace_kprobe *)event->data;
1296 struct trace_event_file *file = data;
1297
1298 switch (type) {
1299 case TRACE_REG_REGISTER:
1300 return enable_trace_kprobe(tk, file);
1301 case TRACE_REG_UNREGISTER:
1302 return disable_trace_kprobe(tk, file);
1303
1304 #ifdef CONFIG_PERF_EVENTS
1305 case TRACE_REG_PERF_REGISTER:
1306 return enable_trace_kprobe(tk, NULL);
1307 case TRACE_REG_PERF_UNREGISTER:
1308 return disable_trace_kprobe(tk, NULL);
1309 case TRACE_REG_PERF_OPEN:
1310 case TRACE_REG_PERF_CLOSE:
1311 case TRACE_REG_PERF_ADD:
1312 case TRACE_REG_PERF_DEL:
1313 return 0;
1314 #endif
1315 }
1316 return 0;
1317 }
1318
1319 static int kprobe_dispatcher(struct kprobe *kp, struct pt_regs *regs)
1320 {
1321 struct trace_kprobe *tk = container_of(kp, struct trace_kprobe, rp.kp);
1322 int ret = 0;
1323
1324 raw_cpu_inc(*tk->nhit);
1325
1326 if (tk->tp.flags & TP_FLAG_TRACE)
1327 kprobe_trace_func(tk, regs);
1328 #ifdef CONFIG_PERF_EVENTS
1329 if (tk->tp.flags & TP_FLAG_PROFILE)
1330 ret = kprobe_perf_func(tk, regs);
1331 #endif
1332 return ret;
1333 }
1334 NOKPROBE_SYMBOL(kprobe_dispatcher);
1335
1336 static int
1337 kretprobe_dispatcher(struct kretprobe_instance *ri, struct pt_regs *regs)
1338 {
1339 struct trace_kprobe *tk = container_of(ri->rp, struct trace_kprobe, rp);
1340
1341 raw_cpu_inc(*tk->nhit);
1342
1343 if (tk->tp.flags & TP_FLAG_TRACE)
1344 kretprobe_trace_func(tk, ri, regs);
1345 #ifdef CONFIG_PERF_EVENTS
1346 if (tk->tp.flags & TP_FLAG_PROFILE)
1347 kretprobe_perf_func(tk, ri, regs);
1348 #endif
1349 return 0; /* We don't tweek kernel, so just return 0 */
1350 }
1351 NOKPROBE_SYMBOL(kretprobe_dispatcher);
1352
1353 static struct trace_event_functions kretprobe_funcs = {
1354 .trace = print_kretprobe_event
1355 };
1356
1357 static struct trace_event_functions kprobe_funcs = {
1358 .trace = print_kprobe_event
1359 };
1360
1361 static int register_kprobe_event(struct trace_kprobe *tk)
1362 {
1363 struct trace_event_call *call = &tk->tp.call;
1364 int ret;
1365
1366 /* Initialize trace_event_call */
1367 INIT_LIST_HEAD(&call->class->fields);
1368 if (trace_kprobe_is_return(tk)) {
1369 call->event.funcs = &kretprobe_funcs;
1370 call->class->define_fields = kretprobe_event_define_fields;
1371 } else {
1372 call->event.funcs = &kprobe_funcs;
1373 call->class->define_fields = kprobe_event_define_fields;
1374 }
1375 if (set_print_fmt(&tk->tp, trace_kprobe_is_return(tk)) < 0)
1376 return -ENOMEM;
1377 ret = register_trace_event(&call->event);
1378 if (!ret) {
1379 kfree(call->print_fmt);
1380 return -ENODEV;
1381 }
1382 call->flags = TRACE_EVENT_FL_KPROBE;
1383 call->class->reg = kprobe_register;
1384 call->data = tk;
1385 ret = trace_add_event_call(call);
1386 if (ret) {
1387 pr_info("Failed to register kprobe event: %s\n",
1388 trace_event_name(call));
1389 kfree(call->print_fmt);
1390 unregister_trace_event(&call->event);
1391 }
1392 return ret;
1393 }
1394
1395 static int unregister_kprobe_event(struct trace_kprobe *tk)
1396 {
1397 int ret;
1398
1399 /* tp->event is unregistered in trace_remove_event_call() */
1400 ret = trace_remove_event_call(&tk->tp.call);
1401 if (!ret)
1402 kfree(tk->tp.call.print_fmt);
1403 return ret;
1404 }
1405
1406 /* Make a tracefs interface for controlling probe points */
1407 static __init int init_kprobe_trace(void)
1408 {
1409 struct dentry *d_tracer;
1410 struct dentry *entry;
1411
1412 if (register_module_notifier(&trace_kprobe_module_nb))
1413 return -EINVAL;
1414
1415 d_tracer = tracing_init_dentry();
1416 if (IS_ERR(d_tracer))
1417 return 0;
1418
1419 entry = tracefs_create_file("kprobe_events", 0644, d_tracer,
1420 NULL, &kprobe_events_ops);
1421
1422 /* Event list interface */
1423 if (!entry)
1424 pr_warn("Could not create tracefs 'kprobe_events' entry\n");
1425
1426 /* Profile interface */
1427 entry = tracefs_create_file("kprobe_profile", 0444, d_tracer,
1428 NULL, &kprobe_profile_ops);
1429
1430 if (!entry)
1431 pr_warn("Could not create tracefs 'kprobe_profile' entry\n");
1432 return 0;
1433 }
1434 fs_initcall(init_kprobe_trace);
1435
1436
1437 #ifdef CONFIG_FTRACE_STARTUP_TEST
1438 /*
1439 * The "__used" keeps gcc from removing the function symbol
1440 * from the kallsyms table. 'noinline' makes sure that there
1441 * isn't an inlined version used by the test method below
1442 */
1443 static __used __init noinline int
1444 kprobe_trace_selftest_target(int a1, int a2, int a3, int a4, int a5, int a6)
1445 {
1446 return a1 + a2 + a3 + a4 + a5 + a6;
1447 }
1448
1449 static __init struct trace_event_file *
1450 find_trace_probe_file(struct trace_kprobe *tk, struct trace_array *tr)
1451 {
1452 struct trace_event_file *file;
1453
1454 list_for_each_entry(file, &tr->events, list)
1455 if (file->event_call == &tk->tp.call)
1456 return file;
1457
1458 return NULL;
1459 }
1460
1461 /*
1462 * Nobody but us can call enable_trace_kprobe/disable_trace_kprobe at this
1463 * stage, we can do this lockless.
1464 */
1465 static __init int kprobe_trace_self_tests_init(void)
1466 {
1467 int ret, warn = 0;
1468 int (*target)(int, int, int, int, int, int);
1469 struct trace_kprobe *tk;
1470 struct trace_event_file *file;
1471
1472 if (tracing_is_disabled())
1473 return -ENODEV;
1474
1475 target = kprobe_trace_selftest_target;
1476
1477 pr_info("Testing kprobe tracing: ");
1478
1479 ret = trace_run_command("p:testprobe kprobe_trace_selftest_target "
1480 "$stack $stack0 +0($stack)",
1481 create_trace_kprobe);
1482 if (WARN_ON_ONCE(ret)) {
1483 pr_warn("error on probing function entry.\n");
1484 warn++;
1485 } else {
1486 /* Enable trace point */
1487 tk = find_trace_kprobe("testprobe", KPROBE_EVENT_SYSTEM);
1488 if (WARN_ON_ONCE(tk == NULL)) {
1489 pr_warn("error on getting new probe.\n");
1490 warn++;
1491 } else {
1492 file = find_trace_probe_file(tk, top_trace_array());
1493 if (WARN_ON_ONCE(file == NULL)) {
1494 pr_warn("error on getting probe file.\n");
1495 warn++;
1496 } else
1497 enable_trace_kprobe(tk, file);
1498 }
1499 }
1500
1501 ret = trace_run_command("r:testprobe2 kprobe_trace_selftest_target "
1502 "$retval", create_trace_kprobe);
1503 if (WARN_ON_ONCE(ret)) {
1504 pr_warn("error on probing function return.\n");
1505 warn++;
1506 } else {
1507 /* Enable trace point */
1508 tk = find_trace_kprobe("testprobe2", KPROBE_EVENT_SYSTEM);
1509 if (WARN_ON_ONCE(tk == NULL)) {
1510 pr_warn("error on getting 2nd new probe.\n");
1511 warn++;
1512 } else {
1513 file = find_trace_probe_file(tk, top_trace_array());
1514 if (WARN_ON_ONCE(file == NULL)) {
1515 pr_warn("error on getting probe file.\n");
1516 warn++;
1517 } else
1518 enable_trace_kprobe(tk, file);
1519 }
1520 }
1521
1522 if (warn)
1523 goto end;
1524
1525 ret = target(1, 2, 3, 4, 5, 6);
1526
1527 /*
1528 * Not expecting an error here, the check is only to prevent the
1529 * optimizer from removing the call to target() as otherwise there
1530 * are no side-effects and the call is never performed.
1531 */
1532 if (ret != 21)
1533 warn++;
1534
1535 /* Disable trace points before removing it */
1536 tk = find_trace_kprobe("testprobe", KPROBE_EVENT_SYSTEM);
1537 if (WARN_ON_ONCE(tk == NULL)) {
1538 pr_warn("error on getting test probe.\n");
1539 warn++;
1540 } else {
1541 if (trace_kprobe_nhit(tk) != 1) {
1542 pr_warn("incorrect number of testprobe hits\n");
1543 warn++;
1544 }
1545
1546 file = find_trace_probe_file(tk, top_trace_array());
1547 if (WARN_ON_ONCE(file == NULL)) {
1548 pr_warn("error on getting probe file.\n");
1549 warn++;
1550 } else
1551 disable_trace_kprobe(tk, file);
1552 }
1553
1554 tk = find_trace_kprobe("testprobe2", KPROBE_EVENT_SYSTEM);
1555 if (WARN_ON_ONCE(tk == NULL)) {
1556 pr_warn("error on getting 2nd test probe.\n");
1557 warn++;
1558 } else {
1559 if (trace_kprobe_nhit(tk) != 1) {
1560 pr_warn("incorrect number of testprobe2 hits\n");
1561 warn++;
1562 }
1563
1564 file = find_trace_probe_file(tk, top_trace_array());
1565 if (WARN_ON_ONCE(file == NULL)) {
1566 pr_warn("error on getting probe file.\n");
1567 warn++;
1568 } else
1569 disable_trace_kprobe(tk, file);
1570 }
1571
1572 ret = trace_run_command("-:testprobe", create_trace_kprobe);
1573 if (WARN_ON_ONCE(ret)) {
1574 pr_warn("error on deleting a probe.\n");
1575 warn++;
1576 }
1577
1578 ret = trace_run_command("-:testprobe2", create_trace_kprobe);
1579 if (WARN_ON_ONCE(ret)) {
1580 pr_warn("error on deleting a probe.\n");
1581 warn++;
1582 }
1583
1584 end:
1585 release_all_trace_kprobes();
1586 /*
1587 * Wait for the optimizer work to finish. Otherwise it might fiddle
1588 * with probes in already freed __init text.
1589 */
1590 wait_for_kprobe_optimizer();
1591 if (warn)
1592 pr_cont("NG: Some tests are failed. Please check them.\n");
1593 else
1594 pr_cont("OK\n");
1595 return 0;
1596 }
1597
1598 late_initcall(kprobe_trace_self_tests_init);
1599
1600 #endif
CRIS linux kernel tree