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xfs: add full xfs_dqblk verifier
[linux/fpc-iii.git] / kernel / trace / trace_kprobe.c
blob02aed76e0978801428ff33f1b8a421a8deb34f14
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
466 /*
467 * if tk is not added to any list, it must be a local trace_kprobe
468 * created with perf_event_open. We don't need to wait for these
469 * trace_kprobes
470 */
471 if (list_empty(&tk->list))
472 wait = 0;
473 out:
474 if (wait) {
475 /*
476 * Synchronize with kprobe_trace_func/kretprobe_trace_func
477 * to ensure disabled (all running handlers are finished).
478 * This is not only for kfree(), but also the caller,
479 * trace_remove_event_call() supposes it for releasing
480 * event_call related objects, which will be accessed in
481 * the kprobe_trace_func/kretprobe_trace_func.
482 */
483 synchronize_sched();
484 kfree(link); /* Ignored if link == NULL */
485 }
486
487 return ret;
488 }
489
490 /* Internal register function - just handle k*probes and flags */
491 static int __register_trace_kprobe(struct trace_kprobe *tk)
492 {
493 int i, ret;
494
495 if (trace_probe_is_registered(&tk->tp))
496 return -EINVAL;
497
498 for (i = 0; i < tk->tp.nr_args; i++)
499 traceprobe_update_arg(&tk->tp.args[i]);
500
501 /* Set/clear disabled flag according to tp->flag */
502 if (trace_probe_is_enabled(&tk->tp))
503 tk->rp.kp.flags &= ~KPROBE_FLAG_DISABLED;
504 else
505 tk->rp.kp.flags |= KPROBE_FLAG_DISABLED;
506
507 if (trace_kprobe_is_return(tk))
508 ret = register_kretprobe(&tk->rp);
509 else
510 ret = register_kprobe(&tk->rp.kp);
511
512 if (ret == 0)
513 tk->tp.flags |= TP_FLAG_REGISTERED;
514 else {
515 if (ret == -ENOENT && trace_kprobe_is_on_module(tk)) {
516 pr_warn("This probe might be able to register after target module is loaded. Continue.\n");
517 ret = 0;
518 } else if (ret == -EILSEQ) {
519 pr_warn("Probing address(0x%p) is not an instruction boundary.\n",
520 tk->rp.kp.addr);
521 ret = -EINVAL;
522 }
523 }
524
525 return ret;
526 }
527
528 /* Internal unregister function - just handle k*probes and flags */
529 static void __unregister_trace_kprobe(struct trace_kprobe *tk)
530 {
531 if (trace_probe_is_registered(&tk->tp)) {
532 if (trace_kprobe_is_return(tk))
533 unregister_kretprobe(&tk->rp);
534 else
535 unregister_kprobe(&tk->rp.kp);
536 tk->tp.flags &= ~TP_FLAG_REGISTERED;
537 /* Cleanup kprobe for reuse */
538 if (tk->rp.kp.symbol_name)
539 tk->rp.kp.addr = NULL;
540 }
541 }
542
543 /* Unregister a trace_probe and probe_event: call with locking probe_lock */
544 static int unregister_trace_kprobe(struct trace_kprobe *tk)
545 {
546 /* Enabled event can not be unregistered */
547 if (trace_probe_is_enabled(&tk->tp))
548 return -EBUSY;
549
550 /* Will fail if probe is being used by ftrace or perf */
551 if (unregister_kprobe_event(tk))
552 return -EBUSY;
553
554 __unregister_trace_kprobe(tk);
555 list_del(&tk->list);
556
557 return 0;
558 }
559
560 /* Register a trace_probe and probe_event */
561 static int register_trace_kprobe(struct trace_kprobe *tk)
562 {
563 struct trace_kprobe *old_tk;
564 int ret;
565
566 mutex_lock(&probe_lock);
567
568 /* Delete old (same name) event if exist */
569 old_tk = find_trace_kprobe(trace_event_name(&tk->tp.call),
570 tk->tp.call.class->system);
571 if (old_tk) {
572 ret = unregister_trace_kprobe(old_tk);
573 if (ret < 0)
574 goto end;
575 free_trace_kprobe(old_tk);
576 }
577
578 /* Register new event */
579 ret = register_kprobe_event(tk);
580 if (ret) {
581 pr_warn("Failed to register probe event(%d)\n", ret);
582 goto end;
583 }
584
585 /* Register k*probe */
586 ret = __register_trace_kprobe(tk);
587 if (ret < 0)
588 unregister_kprobe_event(tk);
589 else
590 list_add_tail(&tk->list, &probe_list);
591
592 end:
593 mutex_unlock(&probe_lock);
594 return ret;
595 }
596
597 /* Module notifier call back, checking event on the module */
598 static int trace_kprobe_module_callback(struct notifier_block *nb,
599 unsigned long val, void *data)
600 {
601 struct module *mod = data;
602 struct trace_kprobe *tk;
603 int ret;
604
605 if (val != MODULE_STATE_COMING)
606 return NOTIFY_DONE;
607
608 /* Update probes on coming module */
609 mutex_lock(&probe_lock);
610 list_for_each_entry(tk, &probe_list, list) {
611 if (trace_kprobe_within_module(tk, mod)) {
612 /* Don't need to check busy - this should have gone. */
613 __unregister_trace_kprobe(tk);
614 ret = __register_trace_kprobe(tk);
615 if (ret)
616 pr_warn("Failed to re-register probe %s on %s: %d\n",
617 trace_event_name(&tk->tp.call),
618 mod->name, ret);
619 }
620 }
621 mutex_unlock(&probe_lock);
622
623 return NOTIFY_DONE;
624 }
625
626 static struct notifier_block trace_kprobe_module_nb = {
627 .notifier_call = trace_kprobe_module_callback,
628 .priority = 1 /* Invoked after kprobe module callback */
629 };
630
631 /* Convert certain expected symbols into '_' when generating event names */
632 static inline void sanitize_event_name(char *name)
633 {
634 while (*name++ != '\0')
635 if (*name == ':' || *name == '.')
636 *name = '_';
637 }
638
639 static int create_trace_kprobe(int argc, char **argv)
640 {
641 /*
642 * Argument syntax:
643 * - Add kprobe:
644 * p[:[GRP/]EVENT] [MOD:]KSYM[+OFFS]|KADDR [FETCHARGS]
645 * - Add kretprobe:
646 * r[MAXACTIVE][:[GRP/]EVENT] [MOD:]KSYM[+0] [FETCHARGS]
647 * Fetch args:
648 * $retval : fetch return value
649 * $stack : fetch stack address
650 * $stackN : fetch Nth of stack (N:0-)
651 * $comm : fetch current task comm
652 * @ADDR : fetch memory at ADDR (ADDR should be in kernel)
653 * @SYM[+|-offs] : fetch memory at SYM +|- offs (SYM is a data symbol)
654 * %REG : fetch register REG
655 * Dereferencing memory fetch:
656 * +|-offs(ARG) : fetch memory at ARG +|- offs address.
657 * Alias name of args:
658 * NAME=FETCHARG : set NAME as alias of FETCHARG.
659 * Type of args:
660 * FETCHARG:TYPE : use TYPE instead of unsigned long.
661 */
662 struct trace_kprobe *tk;
663 int i, ret = 0;
664 bool is_return = false, is_delete = false;
665 char *symbol = NULL, *event = NULL, *group = NULL;
666 int maxactive = 0;
667 char *arg;
668 long offset = 0;
669 void *addr = NULL;
670 char buf[MAX_EVENT_NAME_LEN];
671
672 /* argc must be >= 1 */
673 if (argv[0][0] == 'p')
674 is_return = false;
675 else if (argv[0][0] == 'r')
676 is_return = true;
677 else if (argv[0][0] == '-')
678 is_delete = true;
679 else {
680 pr_info("Probe definition must be started with 'p', 'r' or"
681 " '-'.\n");
682 return -EINVAL;
683 }
684
685 event = strchr(&argv[0][1], ':');
686 if (event) {
687 event[0] = '\0';
688 event++;
689 }
690 if (is_return && isdigit(argv[0][1])) {
691 ret = kstrtouint(&argv[0][1], 0, &maxactive);
692 if (ret) {
693 pr_info("Failed to parse maxactive.\n");
694 return ret;
695 }
696 /* kretprobes instances are iterated over via a list. The
697 * maximum should stay reasonable.
698 */
699 if (maxactive > KRETPROBE_MAXACTIVE_MAX) {
700 pr_info("Maxactive is too big (%d > %d).\n",
701 maxactive, KRETPROBE_MAXACTIVE_MAX);
702 return -E2BIG;
703 }
704 }
705
706 if (event) {
707 if (strchr(event, '/')) {
708 group = event;
709 event = strchr(group, '/') + 1;
710 event[-1] = '\0';
711 if (strlen(group) == 0) {
712 pr_info("Group name is not specified\n");
713 return -EINVAL;
714 }
715 }
716 if (strlen(event) == 0) {
717 pr_info("Event name is not specified\n");
718 return -EINVAL;
719 }
720 }
721 if (!group)
722 group = KPROBE_EVENT_SYSTEM;
723
724 if (is_delete) {
725 if (!event) {
726 pr_info("Delete command needs an event name.\n");
727 return -EINVAL;
728 }
729 mutex_lock(&probe_lock);
730 tk = find_trace_kprobe(event, group);
731 if (!tk) {
732 mutex_unlock(&probe_lock);
733 pr_info("Event %s/%s doesn't exist.\n", group, event);
734 return -ENOENT;
735 }
736 /* delete an event */
737 ret = unregister_trace_kprobe(tk);
738 if (ret == 0)
739 free_trace_kprobe(tk);
740 mutex_unlock(&probe_lock);
741 return ret;
742 }
743
744 if (argc < 2) {
745 pr_info("Probe point is not specified.\n");
746 return -EINVAL;
747 }
748
749 /* try to parse an address. if that fails, try to read the
750 * input as a symbol. */
751 if (kstrtoul(argv[1], 0, (unsigned long *)&addr)) {
752 /* a symbol specified */
753 symbol = argv[1];
754 /* TODO: support .init module functions */
755 ret = traceprobe_split_symbol_offset(symbol, &offset);
756 if (ret || offset < 0 || offset > UINT_MAX) {
757 pr_info("Failed to parse either an address or a symbol.\n");
758 return ret;
759 }
760 if (offset && is_return &&
761 !kprobe_on_func_entry(NULL, symbol, offset)) {
762 pr_info("Given offset is not valid for return probe.\n");
763 return -EINVAL;
764 }
765 }
766 argc -= 2; argv += 2;
767
768 /* setup a probe */
769 if (!event) {
770 /* Make a new event name */
771 if (symbol)
772 snprintf(buf, MAX_EVENT_NAME_LEN, "%c_%s_%ld",
773 is_return ? 'r' : 'p', symbol, offset);
774 else
775 snprintf(buf, MAX_EVENT_NAME_LEN, "%c_0x%p",
776 is_return ? 'r' : 'p', addr);
777 sanitize_event_name(buf);
778 event = buf;
779 }
780 tk = alloc_trace_kprobe(group, event, addr, symbol, offset, maxactive,
781 argc, is_return);
782 if (IS_ERR(tk)) {
783 pr_info("Failed to allocate trace_probe.(%d)\n",
784 (int)PTR_ERR(tk));
785 return PTR_ERR(tk);
786 }
787
788 /* parse arguments */
789 ret = 0;
790 for (i = 0; i < argc && i < MAX_TRACE_ARGS; i++) {
791 struct probe_arg *parg = &tk->tp.args[i];
792
793 /* Increment count for freeing args in error case */
794 tk->tp.nr_args++;
795
796 /* Parse argument name */
797 arg = strchr(argv[i], '=');
798 if (arg) {
799 *arg++ = '\0';
800 parg->name = kstrdup(argv[i], GFP_KERNEL);
801 } else {
802 arg = argv[i];
803 /* If argument name is omitted, set "argN" */
804 snprintf(buf, MAX_EVENT_NAME_LEN, "arg%d", i + 1);
805 parg->name = kstrdup(buf, GFP_KERNEL);
806 }
807
808 if (!parg->name) {
809 pr_info("Failed to allocate argument[%d] name.\n", i);
810 ret = -ENOMEM;
811 goto error;
812 }
813
814 if (!is_good_name(parg->name)) {
815 pr_info("Invalid argument[%d] name: %s\n",
816 i, parg->name);
817 ret = -EINVAL;
818 goto error;
819 }
820
821 if (traceprobe_conflict_field_name(parg->name,
822 tk->tp.args, i)) {
823 pr_info("Argument[%d] name '%s' conflicts with "
824 "another field.\n", i, argv[i]);
825 ret = -EINVAL;
826 goto error;
827 }
828
829 /* Parse fetch argument */
830 ret = traceprobe_parse_probe_arg(arg, &tk->tp.size, parg,
831 is_return, true,
832 kprobes_fetch_type_table);
833 if (ret) {
834 pr_info("Parse error at argument[%d]. (%d)\n", i, ret);
835 goto error;
836 }
837 }
838
839 ret = register_trace_kprobe(tk);
840 if (ret)
841 goto error;
842 return 0;
843
844 error:
845 free_trace_kprobe(tk);
846 return ret;
847 }
848
849 static int release_all_trace_kprobes(void)
850 {
851 struct trace_kprobe *tk;
852 int ret = 0;
853
854 mutex_lock(&probe_lock);
855 /* Ensure no probe is in use. */
856 list_for_each_entry(tk, &probe_list, list)
857 if (trace_probe_is_enabled(&tk->tp)) {
858 ret = -EBUSY;
859 goto end;
860 }
861 /* TODO: Use batch unregistration */
862 while (!list_empty(&probe_list)) {
863 tk = list_entry(probe_list.next, struct trace_kprobe, list);
864 ret = unregister_trace_kprobe(tk);
865 if (ret)
866 goto end;
867 free_trace_kprobe(tk);
868 }
869
870 end:
871 mutex_unlock(&probe_lock);
872
873 return ret;
874 }
875
876 /* Probes listing interfaces */
877 static void *probes_seq_start(struct seq_file *m, loff_t *pos)
878 {
879 mutex_lock(&probe_lock);
880 return seq_list_start(&probe_list, *pos);
881 }
882
883 static void *probes_seq_next(struct seq_file *m, void *v, loff_t *pos)
884 {
885 return seq_list_next(v, &probe_list, pos);
886 }
887
888 static void probes_seq_stop(struct seq_file *m, void *v)
889 {
890 mutex_unlock(&probe_lock);
891 }
892
893 static int probes_seq_show(struct seq_file *m, void *v)
894 {
895 struct trace_kprobe *tk = v;
896 int i;
897
898 seq_putc(m, trace_kprobe_is_return(tk) ? 'r' : 'p');
899 seq_printf(m, ":%s/%s", tk->tp.call.class->system,
900 trace_event_name(&tk->tp.call));
901
902 if (!tk->symbol)
903 seq_printf(m, " 0x%p", tk->rp.kp.addr);
904 else if (tk->rp.kp.offset)
905 seq_printf(m, " %s+%u", trace_kprobe_symbol(tk),
906 tk->rp.kp.offset);
907 else
908 seq_printf(m, " %s", trace_kprobe_symbol(tk));
909
910 for (i = 0; i < tk->tp.nr_args; i++)
911 seq_printf(m, " %s=%s", tk->tp.args[i].name, tk->tp.args[i].comm);
912 seq_putc(m, '\n');
913
914 return 0;
915 }
916
917 static const struct seq_operations probes_seq_op = {
918 .start = probes_seq_start,
919 .next = probes_seq_next,
920 .stop = probes_seq_stop,
921 .show = probes_seq_show
922 };
923
924 static int probes_open(struct inode *inode, struct file *file)
925 {
926 int ret;
927
928 if ((file->f_mode & FMODE_WRITE) && (file->f_flags & O_TRUNC)) {
929 ret = release_all_trace_kprobes();
930 if (ret < 0)
931 return ret;
932 }
933
934 return seq_open(file, &probes_seq_op);
935 }
936
937 static ssize_t probes_write(struct file *file, const char __user *buffer,
938 size_t count, loff_t *ppos)
939 {
940 return trace_parse_run_command(file, buffer, count, ppos,
941 create_trace_kprobe);
942 }
943
944 static const struct file_operations kprobe_events_ops = {
945 .owner = THIS_MODULE,
946 .open = probes_open,
947 .read = seq_read,
948 .llseek = seq_lseek,
949 .release = seq_release,
950 .write = probes_write,
951 };
952
953 /* Probes profiling interfaces */
954 static int probes_profile_seq_show(struct seq_file *m, void *v)
955 {
956 struct trace_kprobe *tk = v;
957
958 seq_printf(m, " %-44s %15lu %15lu\n",
959 trace_event_name(&tk->tp.call),
960 trace_kprobe_nhit(tk),
961 tk->rp.kp.nmissed);
962
963 return 0;
964 }
965
966 static const struct seq_operations profile_seq_op = {
967 .start = probes_seq_start,
968 .next = probes_seq_next,
969 .stop = probes_seq_stop,
970 .show = probes_profile_seq_show
971 };
972
973 static int profile_open(struct inode *inode, struct file *file)
974 {
975 return seq_open(file, &profile_seq_op);
976 }
977
978 static const struct file_operations kprobe_profile_ops = {
979 .owner = THIS_MODULE,
980 .open = profile_open,
981 .read = seq_read,
982 .llseek = seq_lseek,
983 .release = seq_release,
984 };
985
986 /* Kprobe handler */
987 static nokprobe_inline void
988 __kprobe_trace_func(struct trace_kprobe *tk, struct pt_regs *regs,
989 struct trace_event_file *trace_file)
990 {
991 struct kprobe_trace_entry_head *entry;
992 struct ring_buffer_event *event;
993 struct ring_buffer *buffer;
994 int size, dsize, pc;
995 unsigned long irq_flags;
996 struct trace_event_call *call = &tk->tp.call;
997
998 WARN_ON(call != trace_file->event_call);
999
1000 if (trace_trigger_soft_disabled(trace_file))
1001 return;
1002
1003 local_save_flags(irq_flags);
1004 pc = preempt_count();
1005
1006 dsize = __get_data_size(&tk->tp, regs);
1007 size = sizeof(*entry) + tk->tp.size + dsize;
1008
1009 event = trace_event_buffer_lock_reserve(&buffer, trace_file,
1010 call->event.type,
1011 size, irq_flags, pc);
1012 if (!event)
1013 return;
1014
1015 entry = ring_buffer_event_data(event);
1016 entry->ip = (unsigned long)tk->rp.kp.addr;
1017 store_trace_args(sizeof(*entry), &tk->tp, regs, (u8 *)&entry[1], dsize);
1018
1019 event_trigger_unlock_commit_regs(trace_file, buffer, event,
1020 entry, irq_flags, pc, regs);
1021 }
1022
1023 static void
1024 kprobe_trace_func(struct trace_kprobe *tk, struct pt_regs *regs)
1025 {
1026 struct event_file_link *link;
1027
1028 list_for_each_entry_rcu(link, &tk->tp.files, list)
1029 __kprobe_trace_func(tk, regs, link->file);
1030 }
1031 NOKPROBE_SYMBOL(kprobe_trace_func);
1032
1033 /* Kretprobe handler */
1034 static nokprobe_inline void
1035 __kretprobe_trace_func(struct trace_kprobe *tk, struct kretprobe_instance *ri,
1036 struct pt_regs *regs,
1037 struct trace_event_file *trace_file)
1038 {
1039 struct kretprobe_trace_entry_head *entry;
1040 struct ring_buffer_event *event;
1041 struct ring_buffer *buffer;
1042 int size, pc, dsize;
1043 unsigned long irq_flags;
1044 struct trace_event_call *call = &tk->tp.call;
1045
1046 WARN_ON(call != trace_file->event_call);
1047
1048 if (trace_trigger_soft_disabled(trace_file))
1049 return;
1050
1051 local_save_flags(irq_flags);
1052 pc = preempt_count();
1053
1054 dsize = __get_data_size(&tk->tp, regs);
1055 size = sizeof(*entry) + tk->tp.size + dsize;
1056
1057 event = trace_event_buffer_lock_reserve(&buffer, trace_file,
1058 call->event.type,
1059 size, irq_flags, pc);
1060 if (!event)
1061 return;
1062
1063 entry = ring_buffer_event_data(event);
1064 entry->func = (unsigned long)tk->rp.kp.addr;
1065 entry->ret_ip = (unsigned long)ri->ret_addr;
1066 store_trace_args(sizeof(*entry), &tk->tp, regs, (u8 *)&entry[1], dsize);
1067
1068 event_trigger_unlock_commit_regs(trace_file, buffer, event,
1069 entry, irq_flags, pc, regs);
1070 }
1071
1072 static void
1073 kretprobe_trace_func(struct trace_kprobe *tk, struct kretprobe_instance *ri,
1074 struct pt_regs *regs)
1075 {
1076 struct event_file_link *link;
1077
1078 list_for_each_entry_rcu(link, &tk->tp.files, list)
1079 __kretprobe_trace_func(tk, ri, regs, link->file);
1080 }
1081 NOKPROBE_SYMBOL(kretprobe_trace_func);
1082
1083 /* Event entry printers */
1084 static enum print_line_t
1085 print_kprobe_event(struct trace_iterator *iter, int flags,
1086 struct trace_event *event)
1087 {
1088 struct kprobe_trace_entry_head *field;
1089 struct trace_seq *s = &iter->seq;
1090 struct trace_probe *tp;
1091 u8 *data;
1092 int i;
1093
1094 field = (struct kprobe_trace_entry_head *)iter->ent;
1095 tp = container_of(event, struct trace_probe, call.event);
1096
1097 trace_seq_printf(s, "%s: (", trace_event_name(&tp->call));
1098
1099 if (!seq_print_ip_sym(s, field->ip, flags | TRACE_ITER_SYM_OFFSET))
1100 goto out;
1101
1102 trace_seq_putc(s, ')');
1103
1104 data = (u8 *)&field[1];
1105 for (i = 0; i < tp->nr_args; i++)
1106 if (!tp->args[i].type->print(s, tp->args[i].name,
1107 data + tp->args[i].offset, field))
1108 goto out;
1109
1110 trace_seq_putc(s, '\n');
1111 out:
1112 return trace_handle_return(s);
1113 }
1114
1115 static enum print_line_t
1116 print_kretprobe_event(struct trace_iterator *iter, int flags,
1117 struct trace_event *event)
1118 {
1119 struct kretprobe_trace_entry_head *field;
1120 struct trace_seq *s = &iter->seq;
1121 struct trace_probe *tp;
1122 u8 *data;
1123 int i;
1124
1125 field = (struct kretprobe_trace_entry_head *)iter->ent;
1126 tp = container_of(event, struct trace_probe, call.event);
1127
1128 trace_seq_printf(s, "%s: (", trace_event_name(&tp->call));
1129
1130 if (!seq_print_ip_sym(s, field->ret_ip, flags | TRACE_ITER_SYM_OFFSET))
1131 goto out;
1132
1133 trace_seq_puts(s, " <- ");
1134
1135 if (!seq_print_ip_sym(s, field->func, flags & ~TRACE_ITER_SYM_OFFSET))
1136 goto out;
1137
1138 trace_seq_putc(s, ')');
1139
1140 data = (u8 *)&field[1];
1141 for (i = 0; i < tp->nr_args; i++)
1142 if (!tp->args[i].type->print(s, tp->args[i].name,
1143 data + tp->args[i].offset, field))
1144 goto out;
1145
1146 trace_seq_putc(s, '\n');
1147
1148 out:
1149 return trace_handle_return(s);
1150 }
1151
1152
1153 static int kprobe_event_define_fields(struct trace_event_call *event_call)
1154 {
1155 int ret, i;
1156 struct kprobe_trace_entry_head field;
1157 struct trace_kprobe *tk = (struct trace_kprobe *)event_call->data;
1158
1159 DEFINE_FIELD(unsigned long, ip, FIELD_STRING_IP, 0);
1160 /* Set argument names as fields */
1161 for (i = 0; i < tk->tp.nr_args; i++) {
1162 struct probe_arg *parg = &tk->tp.args[i];
1163
1164 ret = trace_define_field(event_call, parg->type->fmttype,
1165 parg->name,
1166 sizeof(field) + parg->offset,
1167 parg->type->size,
1168 parg->type->is_signed,
1169 FILTER_OTHER);
1170 if (ret)
1171 return ret;
1172 }
1173 return 0;
1174 }
1175
1176 static int kretprobe_event_define_fields(struct trace_event_call *event_call)
1177 {
1178 int ret, i;
1179 struct kretprobe_trace_entry_head field;
1180 struct trace_kprobe *tk = (struct trace_kprobe *)event_call->data;
1181
1182 DEFINE_FIELD(unsigned long, func, FIELD_STRING_FUNC, 0);
1183 DEFINE_FIELD(unsigned long, ret_ip, FIELD_STRING_RETIP, 0);
1184 /* Set argument names as fields */
1185 for (i = 0; i < tk->tp.nr_args; i++) {
1186 struct probe_arg *parg = &tk->tp.args[i];
1187
1188 ret = trace_define_field(event_call, parg->type->fmttype,
1189 parg->name,
1190 sizeof(field) + parg->offset,
1191 parg->type->size,
1192 parg->type->is_signed,
1193 FILTER_OTHER);
1194 if (ret)
1195 return ret;
1196 }
1197 return 0;
1198 }
1199
1200 #ifdef CONFIG_PERF_EVENTS
1201
1202 /* Kprobe profile handler */
1203 static int
1204 kprobe_perf_func(struct trace_kprobe *tk, struct pt_regs *regs)
1205 {
1206 struct trace_event_call *call = &tk->tp.call;
1207 struct kprobe_trace_entry_head *entry;
1208 struct hlist_head *head;
1209 int size, __size, dsize;
1210 int rctx;
1211
1212 if (bpf_prog_array_valid(call)) {
1213 unsigned long orig_ip = instruction_pointer(regs);
1214 int ret;
1215
1216 ret = trace_call_bpf(call, regs);
1217
1218 /*
1219 * We need to check and see if we modified the pc of the
1220 * pt_regs, and if so clear the kprobe and return 1 so that we
1221 * don't do the single stepping.
1222 * The ftrace kprobe handler leaves it up to us to re-enable
1223 * preemption here before returning if we've modified the ip.
1224 */
1225 if (orig_ip != instruction_pointer(regs)) {
1226 reset_current_kprobe();
1227 preempt_enable_no_resched();
1228 return 1;
1229 }
1230 if (!ret)
1231 return 0;
1232 }
1233
1234 head = this_cpu_ptr(call->perf_events);
1235 if (hlist_empty(head))
1236 return 0;
1237
1238 dsize = __get_data_size(&tk->tp, regs);
1239 __size = sizeof(*entry) + tk->tp.size + dsize;
1240 size = ALIGN(__size + sizeof(u32), sizeof(u64));
1241 size -= sizeof(u32);
1242
1243 entry = perf_trace_buf_alloc(size, NULL, &rctx);
1244 if (!entry)
1245 return 0;
1246
1247 entry->ip = (unsigned long)tk->rp.kp.addr;
1248 memset(&entry[1], 0, dsize);
1249 store_trace_args(sizeof(*entry), &tk->tp, regs, (u8 *)&entry[1], dsize);
1250 perf_trace_buf_submit(entry, size, rctx, call->event.type, 1, regs,
1251 head, NULL);
1252 return 0;
1253 }
1254 NOKPROBE_SYMBOL(kprobe_perf_func);
1255
1256 /* Kretprobe profile handler */
1257 static void
1258 kretprobe_perf_func(struct trace_kprobe *tk, struct kretprobe_instance *ri,
1259 struct pt_regs *regs)
1260 {
1261 struct trace_event_call *call = &tk->tp.call;
1262 struct kretprobe_trace_entry_head *entry;
1263 struct hlist_head *head;
1264 int size, __size, dsize;
1265 int rctx;
1266
1267 if (bpf_prog_array_valid(call) && !trace_call_bpf(call, regs))
1268 return;
1269
1270 head = this_cpu_ptr(call->perf_events);
1271 if (hlist_empty(head))
1272 return;
1273
1274 dsize = __get_data_size(&tk->tp, regs);
1275 __size = sizeof(*entry) + tk->tp.size + dsize;
1276 size = ALIGN(__size + sizeof(u32), sizeof(u64));
1277 size -= sizeof(u32);
1278
1279 entry = perf_trace_buf_alloc(size, NULL, &rctx);
1280 if (!entry)
1281 return;
1282
1283 entry->func = (unsigned long)tk->rp.kp.addr;
1284 entry->ret_ip = (unsigned long)ri->ret_addr;
1285 store_trace_args(sizeof(*entry), &tk->tp, regs, (u8 *)&entry[1], dsize);
1286 perf_trace_buf_submit(entry, size, rctx, call->event.type, 1, regs,
1287 head, NULL);
1288 }
1289 NOKPROBE_SYMBOL(kretprobe_perf_func);
1290 #endif /* CONFIG_PERF_EVENTS */
1291
1292 /*
1293 * called by perf_trace_init() or __ftrace_set_clr_event() under event_mutex.
1294 *
1295 * kprobe_trace_self_tests_init() does enable_trace_probe/disable_trace_probe
1296 * lockless, but we can't race with this __init function.
1297 */
1298 static int kprobe_register(struct trace_event_call *event,
1299 enum trace_reg type, void *data)
1300 {
1301 struct trace_kprobe *tk = (struct trace_kprobe *)event->data;
1302 struct trace_event_file *file = data;
1303
1304 switch (type) {
1305 case TRACE_REG_REGISTER:
1306 return enable_trace_kprobe(tk, file);
1307 case TRACE_REG_UNREGISTER:
1308 return disable_trace_kprobe(tk, file);
1309
1310 #ifdef CONFIG_PERF_EVENTS
1311 case TRACE_REG_PERF_REGISTER:
1312 return enable_trace_kprobe(tk, NULL);
1313 case TRACE_REG_PERF_UNREGISTER:
1314 return disable_trace_kprobe(tk, NULL);
1315 case TRACE_REG_PERF_OPEN:
1316 case TRACE_REG_PERF_CLOSE:
1317 case TRACE_REG_PERF_ADD:
1318 case TRACE_REG_PERF_DEL:
1319 return 0;
1320 #endif
1321 }
1322 return 0;
1323 }
1324
1325 static int kprobe_dispatcher(struct kprobe *kp, struct pt_regs *regs)
1326 {
1327 struct trace_kprobe *tk = container_of(kp, struct trace_kprobe, rp.kp);
1328 int ret = 0;
1329
1330 raw_cpu_inc(*tk->nhit);
1331
1332 if (tk->tp.flags & TP_FLAG_TRACE)
1333 kprobe_trace_func(tk, regs);
1334 #ifdef CONFIG_PERF_EVENTS
1335 if (tk->tp.flags & TP_FLAG_PROFILE)
1336 ret = kprobe_perf_func(tk, regs);
1337 #endif
1338 return ret;
1339 }
1340 NOKPROBE_SYMBOL(kprobe_dispatcher);
1341
1342 static int
1343 kretprobe_dispatcher(struct kretprobe_instance *ri, struct pt_regs *regs)
1344 {
1345 struct trace_kprobe *tk = container_of(ri->rp, struct trace_kprobe, rp);
1346
1347 raw_cpu_inc(*tk->nhit);
1348
1349 if (tk->tp.flags & TP_FLAG_TRACE)
1350 kretprobe_trace_func(tk, ri, regs);
1351 #ifdef CONFIG_PERF_EVENTS
1352 if (tk->tp.flags & TP_FLAG_PROFILE)
1353 kretprobe_perf_func(tk, ri, regs);
1354 #endif
1355 return 0; /* We don't tweek kernel, so just return 0 */
1356 }
1357 NOKPROBE_SYMBOL(kretprobe_dispatcher);
1358
1359 static struct trace_event_functions kretprobe_funcs = {
1360 .trace = print_kretprobe_event
1361 };
1362
1363 static struct trace_event_functions kprobe_funcs = {
1364 .trace = print_kprobe_event
1365 };
1366
1367 static inline void init_trace_event_call(struct trace_kprobe *tk,
1368 struct trace_event_call *call)
1369 {
1370 INIT_LIST_HEAD(&call->class->fields);
1371 if (trace_kprobe_is_return(tk)) {
1372 call->event.funcs = &kretprobe_funcs;
1373 call->class->define_fields = kretprobe_event_define_fields;
1374 } else {
1375 call->event.funcs = &kprobe_funcs;
1376 call->class->define_fields = kprobe_event_define_fields;
1377 }
1378
1379 call->flags = TRACE_EVENT_FL_KPROBE;
1380 call->class->reg = kprobe_register;
1381 call->data = tk;
1382 }
1383
1384 static int register_kprobe_event(struct trace_kprobe *tk)
1385 {
1386 struct trace_event_call *call = &tk->tp.call;
1387 int ret = 0;
1388
1389 init_trace_event_call(tk, call);
1390
1391 if (set_print_fmt(&tk->tp, trace_kprobe_is_return(tk)) < 0)
1392 return -ENOMEM;
1393 ret = register_trace_event(&call->event);
1394 if (!ret) {
1395 kfree(call->print_fmt);
1396 return -ENODEV;
1397 }
1398 ret = trace_add_event_call(call);
1399 if (ret) {
1400 pr_info("Failed to register kprobe event: %s\n",
1401 trace_event_name(call));
1402 kfree(call->print_fmt);
1403 unregister_trace_event(&call->event);
1404 }
1405 return ret;
1406 }
1407
1408 static int unregister_kprobe_event(struct trace_kprobe *tk)
1409 {
1410 int ret;
1411
1412 /* tp->event is unregistered in trace_remove_event_call() */
1413 ret = trace_remove_event_call(&tk->tp.call);
1414 if (!ret)
1415 kfree(tk->tp.call.print_fmt);
1416 return ret;
1417 }
1418
1419 #ifdef CONFIG_PERF_EVENTS
1420 /* create a trace_kprobe, but don't add it to global lists */
1421 struct trace_event_call *
1422 create_local_trace_kprobe(char *func, void *addr, unsigned long offs,
1423 bool is_return)
1424 {
1425 struct trace_kprobe *tk;
1426 int ret;
1427 char *event;
1428
1429 /*
1430 * local trace_kprobes are not added to probe_list, so they are never
1431 * searched in find_trace_kprobe(). Therefore, there is no concern of
1432 * duplicated name here.
1433 */
1434 event = func ? func : "DUMMY_EVENT";
1435
1436 tk = alloc_trace_kprobe(KPROBE_EVENT_SYSTEM, event, (void *)addr, func,
1437 offs, 0 /* maxactive */, 0 /* nargs */,
1438 is_return);
1439
1440 if (IS_ERR(tk)) {
1441 pr_info("Failed to allocate trace_probe.(%d)\n",
1442 (int)PTR_ERR(tk));
1443 return ERR_CAST(tk);
1444 }
1445
1446 init_trace_event_call(tk, &tk->tp.call);
1447
1448 if (set_print_fmt(&tk->tp, trace_kprobe_is_return(tk)) < 0) {
1449 ret = -ENOMEM;
1450 goto error;
1451 }
1452
1453 ret = __register_trace_kprobe(tk);
1454 if (ret < 0)
1455 goto error;
1456
1457 return &tk->tp.call;
1458 error:
1459 free_trace_kprobe(tk);
1460 return ERR_PTR(ret);
1461 }
1462
1463 void destroy_local_trace_kprobe(struct trace_event_call *event_call)
1464 {
1465 struct trace_kprobe *tk;
1466
1467 tk = container_of(event_call, struct trace_kprobe, tp.call);
1468
1469 if (trace_probe_is_enabled(&tk->tp)) {
1470 WARN_ON(1);
1471 return;
1472 }
1473
1474 __unregister_trace_kprobe(tk);
1475 free_trace_kprobe(tk);
1476 }
1477 #endif /* CONFIG_PERF_EVENTS */
1478
1479 /* Make a tracefs interface for controlling probe points */
1480 static __init int init_kprobe_trace(void)
1481 {
1482 struct dentry *d_tracer;
1483 struct dentry *entry;
1484
1485 if (register_module_notifier(&trace_kprobe_module_nb))
1486 return -EINVAL;
1487
1488 d_tracer = tracing_init_dentry();
1489 if (IS_ERR(d_tracer))
1490 return 0;
1491
1492 entry = tracefs_create_file("kprobe_events", 0644, d_tracer,
1493 NULL, &kprobe_events_ops);
1494
1495 /* Event list interface */
1496 if (!entry)
1497 pr_warn("Could not create tracefs 'kprobe_events' entry\n");
1498
1499 /* Profile interface */
1500 entry = tracefs_create_file("kprobe_profile", 0444, d_tracer,
1501 NULL, &kprobe_profile_ops);
1502
1503 if (!entry)
1504 pr_warn("Could not create tracefs 'kprobe_profile' entry\n");
1505 return 0;
1506 }
1507 fs_initcall(init_kprobe_trace);
1508
1509
1510 #ifdef CONFIG_FTRACE_STARTUP_TEST
1511 /*
1512 * The "__used" keeps gcc from removing the function symbol
1513 * from the kallsyms table. 'noinline' makes sure that there
1514 * isn't an inlined version used by the test method below
1515 */
1516 static __used __init noinline int
1517 kprobe_trace_selftest_target(int a1, int a2, int a3, int a4, int a5, int a6)
1518 {
1519 return a1 + a2 + a3 + a4 + a5 + a6;
1520 }
1521
1522 static __init struct trace_event_file *
1523 find_trace_probe_file(struct trace_kprobe *tk, struct trace_array *tr)
1524 {
1525 struct trace_event_file *file;
1526
1527 list_for_each_entry(file, &tr->events, list)
1528 if (file->event_call == &tk->tp.call)
1529 return file;
1530
1531 return NULL;
1532 }
1533
1534 /*
1535 * Nobody but us can call enable_trace_kprobe/disable_trace_kprobe at this
1536 * stage, we can do this lockless.
1537 */
1538 static __init int kprobe_trace_self_tests_init(void)
1539 {
1540 int ret, warn = 0;
1541 int (*target)(int, int, int, int, int, int);
1542 struct trace_kprobe *tk;
1543 struct trace_event_file *file;
1544
1545 if (tracing_is_disabled())
1546 return -ENODEV;
1547
1548 target = kprobe_trace_selftest_target;
1549
1550 pr_info("Testing kprobe tracing: ");
1551
1552 ret = trace_run_command("p:testprobe kprobe_trace_selftest_target "
1553 "$stack $stack0 +0($stack)",
1554 create_trace_kprobe);
1555 if (WARN_ON_ONCE(ret)) {
1556 pr_warn("error on probing function entry.\n");
1557 warn++;
1558 } else {
1559 /* Enable trace point */
1560 tk = find_trace_kprobe("testprobe", KPROBE_EVENT_SYSTEM);
1561 if (WARN_ON_ONCE(tk == NULL)) {
1562 pr_warn("error on getting new probe.\n");
1563 warn++;
1564 } else {
1565 file = find_trace_probe_file(tk, top_trace_array());
1566 if (WARN_ON_ONCE(file == NULL)) {
1567 pr_warn("error on getting probe file.\n");
1568 warn++;
1569 } else
1570 enable_trace_kprobe(tk, file);
1571 }
1572 }
1573
1574 ret = trace_run_command("r:testprobe2 kprobe_trace_selftest_target "
1575 "$retval", create_trace_kprobe);
1576 if (WARN_ON_ONCE(ret)) {
1577 pr_warn("error on probing function return.\n");
1578 warn++;
1579 } else {
1580 /* Enable trace point */
1581 tk = find_trace_kprobe("testprobe2", KPROBE_EVENT_SYSTEM);
1582 if (WARN_ON_ONCE(tk == NULL)) {
1583 pr_warn("error on getting 2nd new probe.\n");
1584 warn++;
1585 } else {
1586 file = find_trace_probe_file(tk, top_trace_array());
1587 if (WARN_ON_ONCE(file == NULL)) {
1588 pr_warn("error on getting probe file.\n");
1589 warn++;
1590 } else
1591 enable_trace_kprobe(tk, file);
1592 }
1593 }
1594
1595 if (warn)
1596 goto end;
1597
1598 ret = target(1, 2, 3, 4, 5, 6);
1599
1600 /*
1601 * Not expecting an error here, the check is only to prevent the
1602 * optimizer from removing the call to target() as otherwise there
1603 * are no side-effects and the call is never performed.
1604 */
1605 if (ret != 21)
1606 warn++;
1607
1608 /* Disable trace points before removing it */
1609 tk = find_trace_kprobe("testprobe", KPROBE_EVENT_SYSTEM);
1610 if (WARN_ON_ONCE(tk == NULL)) {
1611 pr_warn("error on getting test probe.\n");
1612 warn++;
1613 } else {
1614 if (trace_kprobe_nhit(tk) != 1) {
1615 pr_warn("incorrect number of testprobe hits\n");
1616 warn++;
1617 }
1618
1619 file = find_trace_probe_file(tk, top_trace_array());
1620 if (WARN_ON_ONCE(file == NULL)) {
1621 pr_warn("error on getting probe file.\n");
1622 warn++;
1623 } else
1624 disable_trace_kprobe(tk, file);
1625 }
1626
1627 tk = find_trace_kprobe("testprobe2", KPROBE_EVENT_SYSTEM);
1628 if (WARN_ON_ONCE(tk == NULL)) {
1629 pr_warn("error on getting 2nd test probe.\n");
1630 warn++;
1631 } else {
1632 if (trace_kprobe_nhit(tk) != 1) {
1633 pr_warn("incorrect number of testprobe2 hits\n");
1634 warn++;
1635 }
1636
1637 file = find_trace_probe_file(tk, top_trace_array());
1638 if (WARN_ON_ONCE(file == NULL)) {
1639 pr_warn("error on getting probe file.\n");
1640 warn++;
1641 } else
1642 disable_trace_kprobe(tk, file);
1643 }
1644
1645 ret = trace_run_command("-:testprobe", create_trace_kprobe);
1646 if (WARN_ON_ONCE(ret)) {
1647 pr_warn("error on deleting a probe.\n");
1648 warn++;
1649 }
1650
1651 ret = trace_run_command("-:testprobe2", create_trace_kprobe);
1652 if (WARN_ON_ONCE(ret)) {
1653 pr_warn("error on deleting a probe.\n");
1654 warn++;
1655 }
1656
1657 end:
1658 release_all_trace_kprobes();
1659 /*
1660 * Wait for the optimizer work to finish. Otherwise it might fiddle
1661 * with probes in already freed __init text.
1662 */
1663 wait_for_kprobe_optimizer();
1664 if (warn)
1665 pr_cont("NG: Some tests are failed. Please check them.\n");
1666 else
1667 pr_cont("OK\n");
1668 return 0;
1669 }
1670
1671 late_initcall(kprobe_trace_self_tests_init);
1672
1673 #endif
Linux with added FPC-III support