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Merge tag 'chrome-platform-for-linus-4.13' of git://git.kernel.org/pub/scm/linux...
[linux/fpc-iii.git] / kernel / trace / trace_kprobe.c
blob2c5221819be51e79f504235c131ee4dc93138a91
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
25 #include "trace_probe.h"
26
27 #define KPROBE_EVENT_SYSTEM "kprobes"
28 #define KRETPROBE_MAXACTIVE_MAX 4096
29
30 /**
31 * Kprobe event core functions
32 */
33 struct trace_kprobe {
34 struct list_head list;
35 struct kretprobe rp; /* Use rp.kp for kprobe use */
36 unsigned long __percpu *nhit;
37 const char *symbol; /* symbol name */
38 struct trace_probe tp;
39 };
40
41 #define SIZEOF_TRACE_KPROBE(n) \
42 (offsetof(struct trace_kprobe, tp.args) + \
43 (sizeof(struct probe_arg) * (n)))
44
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 static int register_kprobe_event(struct trace_kprobe *tk);
91 static int unregister_kprobe_event(struct trace_kprobe *tk);
92
93 static DEFINE_MUTEX(probe_lock);
94 static LIST_HEAD(probe_list);
95
96 static int kprobe_dispatcher(struct kprobe *kp, struct pt_regs *regs);
97 static int kretprobe_dispatcher(struct kretprobe_instance *ri,
98 struct pt_regs *regs);
99
100 /* Memory fetching by symbol */
101 struct symbol_cache {
102 char *symbol;
103 long offset;
104 unsigned long addr;
105 };
106
107 unsigned long update_symbol_cache(struct symbol_cache *sc)
108 {
109 sc->addr = (unsigned long)kallsyms_lookup_name(sc->symbol);
110
111 if (sc->addr)
112 sc->addr += sc->offset;
113
114 return sc->addr;
115 }
116
117 void free_symbol_cache(struct symbol_cache *sc)
118 {
119 kfree(sc->symbol);
120 kfree(sc);
121 }
122
123 struct symbol_cache *alloc_symbol_cache(const char *sym, long offset)
124 {
125 struct symbol_cache *sc;
126
127 if (!sym || strlen(sym) == 0)
128 return NULL;
129
130 sc = kzalloc(sizeof(struct symbol_cache), GFP_KERNEL);
131 if (!sc)
132 return NULL;
133
134 sc->symbol = kstrdup(sym, GFP_KERNEL);
135 if (!sc->symbol) {
136 kfree(sc);
137 return NULL;
138 }
139 sc->offset = offset;
140 update_symbol_cache(sc);
141
142 return sc;
143 }
144
145 /*
146 * Kprobes-specific fetch functions
147 */
148 #define DEFINE_FETCH_stack(type) \
149 static void FETCH_FUNC_NAME(stack, type)(struct pt_regs *regs, \
150 void *offset, void *dest) \
151 { \
152 *(type *)dest = (type)regs_get_kernel_stack_nth(regs, \
153 (unsigned int)((unsigned long)offset)); \
154 } \
155 NOKPROBE_SYMBOL(FETCH_FUNC_NAME(stack, type));
156
157 DEFINE_BASIC_FETCH_FUNCS(stack)
158 /* No string on the stack entry */
159 #define fetch_stack_string NULL
160 #define fetch_stack_string_size NULL
161
162 #define DEFINE_FETCH_memory(type) \
163 static void FETCH_FUNC_NAME(memory, type)(struct pt_regs *regs, \
164 void *addr, void *dest) \
165 { \
166 type retval; \
167 if (probe_kernel_address(addr, retval)) \
168 *(type *)dest = 0; \
169 else \
170 *(type *)dest = retval; \
171 } \
172 NOKPROBE_SYMBOL(FETCH_FUNC_NAME(memory, type));
173
174 DEFINE_BASIC_FETCH_FUNCS(memory)
175 /*
176 * Fetch a null-terminated string. Caller MUST set *(u32 *)dest with max
177 * length and relative data location.
178 */
179 static void FETCH_FUNC_NAME(memory, string)(struct pt_regs *regs,
180 void *addr, void *dest)
181 {
182 int maxlen = get_rloc_len(*(u32 *)dest);
183 u8 *dst = get_rloc_data(dest);
184 long ret;
185
186 if (!maxlen)
187 return;
188
189 /*
190 * Try to get string again, since the string can be changed while
191 * probing.
192 */
193 ret = strncpy_from_unsafe(dst, addr, maxlen);
194
195 if (ret < 0) { /* Failed to fetch string */
196 dst[0] = '\0';
197 *(u32 *)dest = make_data_rloc(0, get_rloc_offs(*(u32 *)dest));
198 } else {
199 *(u32 *)dest = make_data_rloc(ret, get_rloc_offs(*(u32 *)dest));
200 }
201 }
202 NOKPROBE_SYMBOL(FETCH_FUNC_NAME(memory, string));
203
204 /* Return the length of string -- including null terminal byte */
205 static void FETCH_FUNC_NAME(memory, string_size)(struct pt_regs *regs,
206 void *addr, void *dest)
207 {
208 mm_segment_t old_fs;
209 int ret, len = 0;
210 u8 c;
211
212 old_fs = get_fs();
213 set_fs(KERNEL_DS);
214 pagefault_disable();
215
216 do {
217 ret = __copy_from_user_inatomic(&c, (u8 *)addr + len, 1);
218 len++;
219 } while (c && ret == 0 && len < MAX_STRING_SIZE);
220
221 pagefault_enable();
222 set_fs(old_fs);
223
224 if (ret < 0) /* Failed to check the length */
225 *(u32 *)dest = 0;
226 else
227 *(u32 *)dest = len;
228 }
229 NOKPROBE_SYMBOL(FETCH_FUNC_NAME(memory, string_size));
230
231 #define DEFINE_FETCH_symbol(type) \
232 void FETCH_FUNC_NAME(symbol, type)(struct pt_regs *regs, void *data, void *dest)\
233 { \
234 struct symbol_cache *sc = data; \
235 if (sc->addr) \
236 fetch_memory_##type(regs, (void *)sc->addr, dest); \
237 else \
238 *(type *)dest = 0; \
239 } \
240 NOKPROBE_SYMBOL(FETCH_FUNC_NAME(symbol, type));
241
242 DEFINE_BASIC_FETCH_FUNCS(symbol)
243 DEFINE_FETCH_symbol(string)
244 DEFINE_FETCH_symbol(string_size)
245
246 /* kprobes don't support file_offset fetch methods */
247 #define fetch_file_offset_u8 NULL
248 #define fetch_file_offset_u16 NULL
249 #define fetch_file_offset_u32 NULL
250 #define fetch_file_offset_u64 NULL
251 #define fetch_file_offset_string NULL
252 #define fetch_file_offset_string_size NULL
253
254 /* Fetch type information table */
255 static const struct fetch_type kprobes_fetch_type_table[] = {
256 /* Special types */
257 [FETCH_TYPE_STRING] = __ASSIGN_FETCH_TYPE("string", string, string,
258 sizeof(u32), 1, "__data_loc char[]"),
259 [FETCH_TYPE_STRSIZE] = __ASSIGN_FETCH_TYPE("string_size", u32,
260 string_size, sizeof(u32), 0, "u32"),
261 /* Basic types */
262 ASSIGN_FETCH_TYPE(u8, u8, 0),
263 ASSIGN_FETCH_TYPE(u16, u16, 0),
264 ASSIGN_FETCH_TYPE(u32, u32, 0),
265 ASSIGN_FETCH_TYPE(u64, u64, 0),
266 ASSIGN_FETCH_TYPE(s8, u8, 1),
267 ASSIGN_FETCH_TYPE(s16, u16, 1),
268 ASSIGN_FETCH_TYPE(s32, u32, 1),
269 ASSIGN_FETCH_TYPE(s64, u64, 1),
270 ASSIGN_FETCH_TYPE_ALIAS(x8, u8, u8, 0),
271 ASSIGN_FETCH_TYPE_ALIAS(x16, u16, u16, 0),
272 ASSIGN_FETCH_TYPE_ALIAS(x32, u32, u32, 0),
273 ASSIGN_FETCH_TYPE_ALIAS(x64, u64, u64, 0),
274
275 ASSIGN_FETCH_TYPE_END
276 };
277
278 /*
279 * Allocate new trace_probe and initialize it (including kprobes).
280 */
281 static struct trace_kprobe *alloc_trace_kprobe(const char *group,
282 const char *event,
283 void *addr,
284 const char *symbol,
285 unsigned long offs,
286 int maxactive,
287 int nargs, bool is_return)
288 {
289 struct trace_kprobe *tk;
290 int ret = -ENOMEM;
291
292 tk = kzalloc(SIZEOF_TRACE_KPROBE(nargs), GFP_KERNEL);
293 if (!tk)
294 return ERR_PTR(ret);
295
296 tk->nhit = alloc_percpu(unsigned long);
297 if (!tk->nhit)
298 goto error;
299
300 if (symbol) {
301 tk->symbol = kstrdup(symbol, GFP_KERNEL);
302 if (!tk->symbol)
303 goto error;
304 tk->rp.kp.symbol_name = tk->symbol;
305 tk->rp.kp.offset = offs;
306 } else
307 tk->rp.kp.addr = addr;
308
309 if (is_return)
310 tk->rp.handler = kretprobe_dispatcher;
311 else
312 tk->rp.kp.pre_handler = kprobe_dispatcher;
313
314 tk->rp.maxactive = maxactive;
315
316 if (!event || !is_good_name(event)) {
317 ret = -EINVAL;
318 goto error;
319 }
320
321 tk->tp.call.class = &tk->tp.class;
322 tk->tp.call.name = kstrdup(event, GFP_KERNEL);
323 if (!tk->tp.call.name)
324 goto error;
325
326 if (!group || !is_good_name(group)) {
327 ret = -EINVAL;
328 goto error;
329 }
330
331 tk->tp.class.system = kstrdup(group, GFP_KERNEL);
332 if (!tk->tp.class.system)
333 goto error;
334
335 INIT_LIST_HEAD(&tk->list);
336 INIT_LIST_HEAD(&tk->tp.files);
337 return tk;
338 error:
339 kfree(tk->tp.call.name);
340 kfree(tk->symbol);
341 free_percpu(tk->nhit);
342 kfree(tk);
343 return ERR_PTR(ret);
344 }
345
346 static void free_trace_kprobe(struct trace_kprobe *tk)
347 {
348 int i;
349
350 for (i = 0; i < tk->tp.nr_args; i++)
351 traceprobe_free_probe_arg(&tk->tp.args[i]);
352
353 kfree(tk->tp.call.class->system);
354 kfree(tk->tp.call.name);
355 kfree(tk->symbol);
356 free_percpu(tk->nhit);
357 kfree(tk);
358 }
359
360 static struct trace_kprobe *find_trace_kprobe(const char *event,
361 const char *group)
362 {
363 struct trace_kprobe *tk;
364
365 list_for_each_entry(tk, &probe_list, list)
366 if (strcmp(trace_event_name(&tk->tp.call), event) == 0 &&
367 strcmp(tk->tp.call.class->system, group) == 0)
368 return tk;
369 return NULL;
370 }
371
372 /*
373 * Enable trace_probe
374 * if the file is NULL, enable "perf" handler, or enable "trace" handler.
375 */
376 static int
377 enable_trace_kprobe(struct trace_kprobe *tk, struct trace_event_file *file)
378 {
379 int ret = 0;
380
381 if (file) {
382 struct event_file_link *link;
383
384 link = kmalloc(sizeof(*link), GFP_KERNEL);
385 if (!link) {
386 ret = -ENOMEM;
387 goto out;
388 }
389
390 link->file = file;
391 list_add_tail_rcu(&link->list, &tk->tp.files);
392
393 tk->tp.flags |= TP_FLAG_TRACE;
394 } else
395 tk->tp.flags |= TP_FLAG_PROFILE;
396
397 if (trace_probe_is_registered(&tk->tp) && !trace_kprobe_has_gone(tk)) {
398 if (trace_kprobe_is_return(tk))
399 ret = enable_kretprobe(&tk->rp);
400 else
401 ret = enable_kprobe(&tk->rp.kp);
402 }
403 out:
404 return ret;
405 }
406
407 /*
408 * Disable trace_probe
409 * if the file is NULL, disable "perf" handler, or disable "trace" handler.
410 */
411 static int
412 disable_trace_kprobe(struct trace_kprobe *tk, struct trace_event_file *file)
413 {
414 struct event_file_link *link = NULL;
415 int wait = 0;
416 int ret = 0;
417
418 if (file) {
419 link = find_event_file_link(&tk->tp, file);
420 if (!link) {
421 ret = -EINVAL;
422 goto out;
423 }
424
425 list_del_rcu(&link->list);
426 wait = 1;
427 if (!list_empty(&tk->tp.files))
428 goto out;
429
430 tk->tp.flags &= ~TP_FLAG_TRACE;
431 } else
432 tk->tp.flags &= ~TP_FLAG_PROFILE;
433
434 if (!trace_probe_is_enabled(&tk->tp) && trace_probe_is_registered(&tk->tp)) {
435 if (trace_kprobe_is_return(tk))
436 disable_kretprobe(&tk->rp);
437 else
438 disable_kprobe(&tk->rp.kp);
439 wait = 1;
440 }
441 out:
442 if (wait) {
443 /*
444 * Synchronize with kprobe_trace_func/kretprobe_trace_func
445 * to ensure disabled (all running handlers are finished).
446 * This is not only for kfree(), but also the caller,
447 * trace_remove_event_call() supposes it for releasing
448 * event_call related objects, which will be accessed in
449 * the kprobe_trace_func/kretprobe_trace_func.
450 */
451 synchronize_sched();
452 kfree(link); /* Ignored if link == NULL */
453 }
454
455 return ret;
456 }
457
458 /* Internal register function - just handle k*probes and flags */
459 static int __register_trace_kprobe(struct trace_kprobe *tk)
460 {
461 int i, ret;
462
463 if (trace_probe_is_registered(&tk->tp))
464 return -EINVAL;
465
466 for (i = 0; i < tk->tp.nr_args; i++)
467 traceprobe_update_arg(&tk->tp.args[i]);
468
469 /* Set/clear disabled flag according to tp->flag */
470 if (trace_probe_is_enabled(&tk->tp))
471 tk->rp.kp.flags &= ~KPROBE_FLAG_DISABLED;
472 else
473 tk->rp.kp.flags |= KPROBE_FLAG_DISABLED;
474
475 if (trace_kprobe_is_return(tk))
476 ret = register_kretprobe(&tk->rp);
477 else
478 ret = register_kprobe(&tk->rp.kp);
479
480 if (ret == 0)
481 tk->tp.flags |= TP_FLAG_REGISTERED;
482 else {
483 pr_warn("Could not insert probe at %s+%lu: %d\n",
484 trace_kprobe_symbol(tk), trace_kprobe_offset(tk), ret);
485 if (ret == -ENOENT && trace_kprobe_is_on_module(tk)) {
486 pr_warn("This probe might be able to register after target module is loaded. Continue.\n");
487 ret = 0;
488 } else if (ret == -EILSEQ) {
489 pr_warn("Probing address(0x%p) is not an instruction boundary.\n",
490 tk->rp.kp.addr);
491 ret = -EINVAL;
492 }
493 }
494
495 return ret;
496 }
497
498 /* Internal unregister function - just handle k*probes and flags */
499 static void __unregister_trace_kprobe(struct trace_kprobe *tk)
500 {
501 if (trace_probe_is_registered(&tk->tp)) {
502 if (trace_kprobe_is_return(tk))
503 unregister_kretprobe(&tk->rp);
504 else
505 unregister_kprobe(&tk->rp.kp);
506 tk->tp.flags &= ~TP_FLAG_REGISTERED;
507 /* Cleanup kprobe for reuse */
508 if (tk->rp.kp.symbol_name)
509 tk->rp.kp.addr = NULL;
510 }
511 }
512
513 /* Unregister a trace_probe and probe_event: call with locking probe_lock */
514 static int unregister_trace_kprobe(struct trace_kprobe *tk)
515 {
516 /* Enabled event can not be unregistered */
517 if (trace_probe_is_enabled(&tk->tp))
518 return -EBUSY;
519
520 /* Will fail if probe is being used by ftrace or perf */
521 if (unregister_kprobe_event(tk))
522 return -EBUSY;
523
524 __unregister_trace_kprobe(tk);
525 list_del(&tk->list);
526
527 return 0;
528 }
529
530 /* Register a trace_probe and probe_event */
531 static int register_trace_kprobe(struct trace_kprobe *tk)
532 {
533 struct trace_kprobe *old_tk;
534 int ret;
535
536 mutex_lock(&probe_lock);
537
538 /* Delete old (same name) event if exist */
539 old_tk = find_trace_kprobe(trace_event_name(&tk->tp.call),
540 tk->tp.call.class->system);
541 if (old_tk) {
542 ret = unregister_trace_kprobe(old_tk);
543 if (ret < 0)
544 goto end;
545 free_trace_kprobe(old_tk);
546 }
547
548 /* Register new event */
549 ret = register_kprobe_event(tk);
550 if (ret) {
551 pr_warn("Failed to register probe event(%d)\n", ret);
552 goto end;
553 }
554
555 /* Register k*probe */
556 ret = __register_trace_kprobe(tk);
557 if (ret < 0)
558 unregister_kprobe_event(tk);
559 else
560 list_add_tail(&tk->list, &probe_list);
561
562 end:
563 mutex_unlock(&probe_lock);
564 return ret;
565 }
566
567 /* Module notifier call back, checking event on the module */
568 static int trace_kprobe_module_callback(struct notifier_block *nb,
569 unsigned long val, void *data)
570 {
571 struct module *mod = data;
572 struct trace_kprobe *tk;
573 int ret;
574
575 if (val != MODULE_STATE_COMING)
576 return NOTIFY_DONE;
577
578 /* Update probes on coming module */
579 mutex_lock(&probe_lock);
580 list_for_each_entry(tk, &probe_list, list) {
581 if (trace_kprobe_within_module(tk, mod)) {
582 /* Don't need to check busy - this should have gone. */
583 __unregister_trace_kprobe(tk);
584 ret = __register_trace_kprobe(tk);
585 if (ret)
586 pr_warn("Failed to re-register probe %s on %s: %d\n",
587 trace_event_name(&tk->tp.call),
588 mod->name, ret);
589 }
590 }
591 mutex_unlock(&probe_lock);
592
593 return NOTIFY_DONE;
594 }
595
596 static struct notifier_block trace_kprobe_module_nb = {
597 .notifier_call = trace_kprobe_module_callback,
598 .priority = 1 /* Invoked after kprobe module callback */
599 };
600
601 static int create_trace_kprobe(int argc, char **argv)
602 {
603 /*
604 * Argument syntax:
605 * - Add kprobe:
606 * p[:[GRP/]EVENT] [MOD:]KSYM[+OFFS]|KADDR [FETCHARGS]
607 * - Add kretprobe:
608 * r[MAXACTIVE][:[GRP/]EVENT] [MOD:]KSYM[+0] [FETCHARGS]
609 * Fetch args:
610 * $retval : fetch return value
611 * $stack : fetch stack address
612 * $stackN : fetch Nth of stack (N:0-)
613 * $comm : fetch current task comm
614 * @ADDR : fetch memory at ADDR (ADDR should be in kernel)
615 * @SYM[+|-offs] : fetch memory at SYM +|- offs (SYM is a data symbol)
616 * %REG : fetch register REG
617 * Dereferencing memory fetch:
618 * +|-offs(ARG) : fetch memory at ARG +|- offs address.
619 * Alias name of args:
620 * NAME=FETCHARG : set NAME as alias of FETCHARG.
621 * Type of args:
622 * FETCHARG:TYPE : use TYPE instead of unsigned long.
623 */
624 struct trace_kprobe *tk;
625 int i, ret = 0;
626 bool is_return = false, is_delete = false;
627 char *symbol = NULL, *event = NULL, *group = NULL;
628 int maxactive = 0;
629 char *arg;
630 unsigned long offset = 0;
631 void *addr = NULL;
632 char buf[MAX_EVENT_NAME_LEN];
633
634 /* argc must be >= 1 */
635 if (argv[0][0] == 'p')
636 is_return = false;
637 else if (argv[0][0] == 'r')
638 is_return = true;
639 else if (argv[0][0] == '-')
640 is_delete = true;
641 else {
642 pr_info("Probe definition must be started with 'p', 'r' or"
643 " '-'.\n");
644 return -EINVAL;
645 }
646
647 event = strchr(&argv[0][1], ':');
648 if (event) {
649 event[0] = '\0';
650 event++;
651 }
652 if (is_return && isdigit(argv[0][1])) {
653 ret = kstrtouint(&argv[0][1], 0, &maxactive);
654 if (ret) {
655 pr_info("Failed to parse maxactive.\n");
656 return ret;
657 }
658 /* kretprobes instances are iterated over via a list. The
659 * maximum should stay reasonable.
660 */
661 if (maxactive > KRETPROBE_MAXACTIVE_MAX) {
662 pr_info("Maxactive is too big (%d > %d).\n",
663 maxactive, KRETPROBE_MAXACTIVE_MAX);
664 return -E2BIG;
665 }
666 }
667
668 if (event) {
669 if (strchr(event, '/')) {
670 group = event;
671 event = strchr(group, '/') + 1;
672 event[-1] = '\0';
673 if (strlen(group) == 0) {
674 pr_info("Group name is not specified\n");
675 return -EINVAL;
676 }
677 }
678 if (strlen(event) == 0) {
679 pr_info("Event name is not specified\n");
680 return -EINVAL;
681 }
682 }
683 if (!group)
684 group = KPROBE_EVENT_SYSTEM;
685
686 if (is_delete) {
687 if (!event) {
688 pr_info("Delete command needs an event name.\n");
689 return -EINVAL;
690 }
691 mutex_lock(&probe_lock);
692 tk = find_trace_kprobe(event, group);
693 if (!tk) {
694 mutex_unlock(&probe_lock);
695 pr_info("Event %s/%s doesn't exist.\n", group, event);
696 return -ENOENT;
697 }
698 /* delete an event */
699 ret = unregister_trace_kprobe(tk);
700 if (ret == 0)
701 free_trace_kprobe(tk);
702 mutex_unlock(&probe_lock);
703 return ret;
704 }
705
706 if (argc < 2) {
707 pr_info("Probe point is not specified.\n");
708 return -EINVAL;
709 }
710
711 /* try to parse an address. if that fails, try to read the
712 * input as a symbol. */
713 if (kstrtoul(argv[1], 0, (unsigned long *)&addr)) {
714 /* a symbol specified */
715 symbol = argv[1];
716 /* TODO: support .init module functions */
717 ret = traceprobe_split_symbol_offset(symbol, &offset);
718 if (ret) {
719 pr_info("Failed to parse either an address or a symbol.\n");
720 return ret;
721 }
722 if (offset && is_return &&
723 !kprobe_on_func_entry(NULL, symbol, offset)) {
724 pr_info("Given offset is not valid for return probe.\n");
725 return -EINVAL;
726 }
727 }
728 argc -= 2; argv += 2;
729
730 /* setup a probe */
731 if (!event) {
732 /* Make a new event name */
733 if (symbol)
734 snprintf(buf, MAX_EVENT_NAME_LEN, "%c_%s_%ld",
735 is_return ? 'r' : 'p', symbol, offset);
736 else
737 snprintf(buf, MAX_EVENT_NAME_LEN, "%c_0x%p",
738 is_return ? 'r' : 'p', addr);
739 event = buf;
740 }
741 tk = alloc_trace_kprobe(group, event, addr, symbol, offset, maxactive,
742 argc, is_return);
743 if (IS_ERR(tk)) {
744 pr_info("Failed to allocate trace_probe.(%d)\n",
745 (int)PTR_ERR(tk));
746 return PTR_ERR(tk);
747 }
748
749 /* parse arguments */
750 ret = 0;
751 for (i = 0; i < argc && i < MAX_TRACE_ARGS; i++) {
752 struct probe_arg *parg = &tk->tp.args[i];
753
754 /* Increment count for freeing args in error case */
755 tk->tp.nr_args++;
756
757 /* Parse argument name */
758 arg = strchr(argv[i], '=');
759 if (arg) {
760 *arg++ = '\0';
761 parg->name = kstrdup(argv[i], GFP_KERNEL);
762 } else {
763 arg = argv[i];
764 /* If argument name is omitted, set "argN" */
765 snprintf(buf, MAX_EVENT_NAME_LEN, "arg%d", i + 1);
766 parg->name = kstrdup(buf, GFP_KERNEL);
767 }
768
769 if (!parg->name) {
770 pr_info("Failed to allocate argument[%d] name.\n", i);
771 ret = -ENOMEM;
772 goto error;
773 }
774
775 if (!is_good_name(parg->name)) {
776 pr_info("Invalid argument[%d] name: %s\n",
777 i, parg->name);
778 ret = -EINVAL;
779 goto error;
780 }
781
782 if (traceprobe_conflict_field_name(parg->name,
783 tk->tp.args, i)) {
784 pr_info("Argument[%d] name '%s' conflicts with "
785 "another field.\n", i, argv[i]);
786 ret = -EINVAL;
787 goto error;
788 }
789
790 /* Parse fetch argument */
791 ret = traceprobe_parse_probe_arg(arg, &tk->tp.size, parg,
792 is_return, true,
793 kprobes_fetch_type_table);
794 if (ret) {
795 pr_info("Parse error at argument[%d]. (%d)\n", i, ret);
796 goto error;
797 }
798 }
799
800 ret = register_trace_kprobe(tk);
801 if (ret)
802 goto error;
803 return 0;
804
805 error:
806 free_trace_kprobe(tk);
807 return ret;
808 }
809
810 static int release_all_trace_kprobes(void)
811 {
812 struct trace_kprobe *tk;
813 int ret = 0;
814
815 mutex_lock(&probe_lock);
816 /* Ensure no probe is in use. */
817 list_for_each_entry(tk, &probe_list, list)
818 if (trace_probe_is_enabled(&tk->tp)) {
819 ret = -EBUSY;
820 goto end;
821 }
822 /* TODO: Use batch unregistration */
823 while (!list_empty(&probe_list)) {
824 tk = list_entry(probe_list.next, struct trace_kprobe, list);
825 ret = unregister_trace_kprobe(tk);
826 if (ret)
827 goto end;
828 free_trace_kprobe(tk);
829 }
830
831 end:
832 mutex_unlock(&probe_lock);
833
834 return ret;
835 }
836
837 /* Probes listing interfaces */
838 static void *probes_seq_start(struct seq_file *m, loff_t *pos)
839 {
840 mutex_lock(&probe_lock);
841 return seq_list_start(&probe_list, *pos);
842 }
843
844 static void *probes_seq_next(struct seq_file *m, void *v, loff_t *pos)
845 {
846 return seq_list_next(v, &probe_list, pos);
847 }
848
849 static void probes_seq_stop(struct seq_file *m, void *v)
850 {
851 mutex_unlock(&probe_lock);
852 }
853
854 static int probes_seq_show(struct seq_file *m, void *v)
855 {
856 struct trace_kprobe *tk = v;
857 int i;
858
859 seq_putc(m, trace_kprobe_is_return(tk) ? 'r' : 'p');
860 seq_printf(m, ":%s/%s", tk->tp.call.class->system,
861 trace_event_name(&tk->tp.call));
862
863 if (!tk->symbol)
864 seq_printf(m, " 0x%p", tk->rp.kp.addr);
865 else if (tk->rp.kp.offset)
866 seq_printf(m, " %s+%u", trace_kprobe_symbol(tk),
867 tk->rp.kp.offset);
868 else
869 seq_printf(m, " %s", trace_kprobe_symbol(tk));
870
871 for (i = 0; i < tk->tp.nr_args; i++)
872 seq_printf(m, " %s=%s", tk->tp.args[i].name, tk->tp.args[i].comm);
873 seq_putc(m, '\n');
874
875 return 0;
876 }
877
878 static const struct seq_operations probes_seq_op = {
879 .start = probes_seq_start,
880 .next = probes_seq_next,
881 .stop = probes_seq_stop,
882 .show = probes_seq_show
883 };
884
885 static int probes_open(struct inode *inode, struct file *file)
886 {
887 int ret;
888
889 if ((file->f_mode & FMODE_WRITE) && (file->f_flags & O_TRUNC)) {
890 ret = release_all_trace_kprobes();
891 if (ret < 0)
892 return ret;
893 }
894
895 return seq_open(file, &probes_seq_op);
896 }
897
898 static ssize_t probes_write(struct file *file, const char __user *buffer,
899 size_t count, loff_t *ppos)
900 {
901 return traceprobe_probes_write(file, buffer, count, ppos,
902 create_trace_kprobe);
903 }
904
905 static const struct file_operations kprobe_events_ops = {
906 .owner = THIS_MODULE,
907 .open = probes_open,
908 .read = seq_read,
909 .llseek = seq_lseek,
910 .release = seq_release,
911 .write = probes_write,
912 };
913
914 /* Probes profiling interfaces */
915 static int probes_profile_seq_show(struct seq_file *m, void *v)
916 {
917 struct trace_kprobe *tk = v;
918
919 seq_printf(m, " %-44s %15lu %15lu\n",
920 trace_event_name(&tk->tp.call),
921 trace_kprobe_nhit(tk),
922 tk->rp.kp.nmissed);
923
924 return 0;
925 }
926
927 static const struct seq_operations profile_seq_op = {
928 .start = probes_seq_start,
929 .next = probes_seq_next,
930 .stop = probes_seq_stop,
931 .show = probes_profile_seq_show
932 };
933
934 static int profile_open(struct inode *inode, struct file *file)
935 {
936 return seq_open(file, &profile_seq_op);
937 }
938
939 static const struct file_operations kprobe_profile_ops = {
940 .owner = THIS_MODULE,
941 .open = profile_open,
942 .read = seq_read,
943 .llseek = seq_lseek,
944 .release = seq_release,
945 };
946
947 /* Kprobe handler */
948 static nokprobe_inline void
949 __kprobe_trace_func(struct trace_kprobe *tk, struct pt_regs *regs,
950 struct trace_event_file *trace_file)
951 {
952 struct kprobe_trace_entry_head *entry;
953 struct ring_buffer_event *event;
954 struct ring_buffer *buffer;
955 int size, dsize, pc;
956 unsigned long irq_flags;
957 struct trace_event_call *call = &tk->tp.call;
958
959 WARN_ON(call != trace_file->event_call);
960
961 if (trace_trigger_soft_disabled(trace_file))
962 return;
963
964 local_save_flags(irq_flags);
965 pc = preempt_count();
966
967 dsize = __get_data_size(&tk->tp, regs);
968 size = sizeof(*entry) + tk->tp.size + dsize;
969
970 event = trace_event_buffer_lock_reserve(&buffer, trace_file,
971 call->event.type,
972 size, irq_flags, pc);
973 if (!event)
974 return;
975
976 entry = ring_buffer_event_data(event);
977 entry->ip = (unsigned long)tk->rp.kp.addr;
978 store_trace_args(sizeof(*entry), &tk->tp, regs, (u8 *)&entry[1], dsize);
979
980 event_trigger_unlock_commit_regs(trace_file, buffer, event,
981 entry, irq_flags, pc, regs);
982 }
983
984 static void
985 kprobe_trace_func(struct trace_kprobe *tk, struct pt_regs *regs)
986 {
987 struct event_file_link *link;
988
989 list_for_each_entry_rcu(link, &tk->tp.files, list)
990 __kprobe_trace_func(tk, regs, link->file);
991 }
992 NOKPROBE_SYMBOL(kprobe_trace_func);
993
994 /* Kretprobe handler */
995 static nokprobe_inline void
996 __kretprobe_trace_func(struct trace_kprobe *tk, struct kretprobe_instance *ri,
997 struct pt_regs *regs,
998 struct trace_event_file *trace_file)
999 {
1000 struct kretprobe_trace_entry_head *entry;
1001 struct ring_buffer_event *event;
1002 struct ring_buffer *buffer;
1003 int size, pc, dsize;
1004 unsigned long irq_flags;
1005 struct trace_event_call *call = &tk->tp.call;
1006
1007 WARN_ON(call != trace_file->event_call);
1008
1009 if (trace_trigger_soft_disabled(trace_file))
1010 return;
1011
1012 local_save_flags(irq_flags);
1013 pc = preempt_count();
1014
1015 dsize = __get_data_size(&tk->tp, regs);
1016 size = sizeof(*entry) + tk->tp.size + dsize;
1017
1018 event = trace_event_buffer_lock_reserve(&buffer, trace_file,
1019 call->event.type,
1020 size, irq_flags, pc);
1021 if (!event)
1022 return;
1023
1024 entry = ring_buffer_event_data(event);
1025 entry->func = (unsigned long)tk->rp.kp.addr;
1026 entry->ret_ip = (unsigned long)ri->ret_addr;
1027 store_trace_args(sizeof(*entry), &tk->tp, regs, (u8 *)&entry[1], dsize);
1028
1029 event_trigger_unlock_commit_regs(trace_file, buffer, event,
1030 entry, irq_flags, pc, regs);
1031 }
1032
1033 static void
1034 kretprobe_trace_func(struct trace_kprobe *tk, struct kretprobe_instance *ri,
1035 struct pt_regs *regs)
1036 {
1037 struct event_file_link *link;
1038
1039 list_for_each_entry_rcu(link, &tk->tp.files, list)
1040 __kretprobe_trace_func(tk, ri, regs, link->file);
1041 }
1042 NOKPROBE_SYMBOL(kretprobe_trace_func);
1043
1044 /* Event entry printers */
1045 static enum print_line_t
1046 print_kprobe_event(struct trace_iterator *iter, int flags,
1047 struct trace_event *event)
1048 {
1049 struct kprobe_trace_entry_head *field;
1050 struct trace_seq *s = &iter->seq;
1051 struct trace_probe *tp;
1052 u8 *data;
1053 int i;
1054
1055 field = (struct kprobe_trace_entry_head *)iter->ent;
1056 tp = container_of(event, struct trace_probe, call.event);
1057
1058 trace_seq_printf(s, "%s: (", trace_event_name(&tp->call));
1059
1060 if (!seq_print_ip_sym(s, field->ip, flags | TRACE_ITER_SYM_OFFSET))
1061 goto out;
1062
1063 trace_seq_putc(s, ')');
1064
1065 data = (u8 *)&field[1];
1066 for (i = 0; i < tp->nr_args; i++)
1067 if (!tp->args[i].type->print(s, tp->args[i].name,
1068 data + tp->args[i].offset, field))
1069 goto out;
1070
1071 trace_seq_putc(s, '\n');
1072 out:
1073 return trace_handle_return(s);
1074 }
1075
1076 static enum print_line_t
1077 print_kretprobe_event(struct trace_iterator *iter, int flags,
1078 struct trace_event *event)
1079 {
1080 struct kretprobe_trace_entry_head *field;
1081 struct trace_seq *s = &iter->seq;
1082 struct trace_probe *tp;
1083 u8 *data;
1084 int i;
1085
1086 field = (struct kretprobe_trace_entry_head *)iter->ent;
1087 tp = container_of(event, struct trace_probe, call.event);
1088
1089 trace_seq_printf(s, "%s: (", trace_event_name(&tp->call));
1090
1091 if (!seq_print_ip_sym(s, field->ret_ip, flags | TRACE_ITER_SYM_OFFSET))
1092 goto out;
1093
1094 trace_seq_puts(s, " <- ");
1095
1096 if (!seq_print_ip_sym(s, field->func, flags & ~TRACE_ITER_SYM_OFFSET))
1097 goto out;
1098
1099 trace_seq_putc(s, ')');
1100
1101 data = (u8 *)&field[1];
1102 for (i = 0; i < tp->nr_args; i++)
1103 if (!tp->args[i].type->print(s, tp->args[i].name,
1104 data + tp->args[i].offset, field))
1105 goto out;
1106
1107 trace_seq_putc(s, '\n');
1108
1109 out:
1110 return trace_handle_return(s);
1111 }
1112
1113
1114 static int kprobe_event_define_fields(struct trace_event_call *event_call)
1115 {
1116 int ret, i;
1117 struct kprobe_trace_entry_head field;
1118 struct trace_kprobe *tk = (struct trace_kprobe *)event_call->data;
1119
1120 DEFINE_FIELD(unsigned long, ip, FIELD_STRING_IP, 0);
1121 /* Set argument names as fields */
1122 for (i = 0; i < tk->tp.nr_args; i++) {
1123 struct probe_arg *parg = &tk->tp.args[i];
1124
1125 ret = trace_define_field(event_call, parg->type->fmttype,
1126 parg->name,
1127 sizeof(field) + parg->offset,
1128 parg->type->size,
1129 parg->type->is_signed,
1130 FILTER_OTHER);
1131 if (ret)
1132 return ret;
1133 }
1134 return 0;
1135 }
1136
1137 static int kretprobe_event_define_fields(struct trace_event_call *event_call)
1138 {
1139 int ret, i;
1140 struct kretprobe_trace_entry_head field;
1141 struct trace_kprobe *tk = (struct trace_kprobe *)event_call->data;
1142
1143 DEFINE_FIELD(unsigned long, func, FIELD_STRING_FUNC, 0);
1144 DEFINE_FIELD(unsigned long, ret_ip, FIELD_STRING_RETIP, 0);
1145 /* Set argument names as fields */
1146 for (i = 0; i < tk->tp.nr_args; i++) {
1147 struct probe_arg *parg = &tk->tp.args[i];
1148
1149 ret = trace_define_field(event_call, parg->type->fmttype,
1150 parg->name,
1151 sizeof(field) + parg->offset,
1152 parg->type->size,
1153 parg->type->is_signed,
1154 FILTER_OTHER);
1155 if (ret)
1156 return ret;
1157 }
1158 return 0;
1159 }
1160
1161 #ifdef CONFIG_PERF_EVENTS
1162
1163 /* Kprobe profile handler */
1164 static void
1165 kprobe_perf_func(struct trace_kprobe *tk, struct pt_regs *regs)
1166 {
1167 struct trace_event_call *call = &tk->tp.call;
1168 struct bpf_prog *prog = call->prog;
1169 struct kprobe_trace_entry_head *entry;
1170 struct hlist_head *head;
1171 int size, __size, dsize;
1172 int rctx;
1173
1174 if (prog && !trace_call_bpf(prog, regs))
1175 return;
1176
1177 head = this_cpu_ptr(call->perf_events);
1178 if (hlist_empty(head))
1179 return;
1180
1181 dsize = __get_data_size(&tk->tp, regs);
1182 __size = sizeof(*entry) + tk->tp.size + dsize;
1183 size = ALIGN(__size + sizeof(u32), sizeof(u64));
1184 size -= sizeof(u32);
1185
1186 entry = perf_trace_buf_alloc(size, NULL, &rctx);
1187 if (!entry)
1188 return;
1189
1190 entry->ip = (unsigned long)tk->rp.kp.addr;
1191 memset(&entry[1], 0, dsize);
1192 store_trace_args(sizeof(*entry), &tk->tp, regs, (u8 *)&entry[1], dsize);
1193 perf_trace_buf_submit(entry, size, rctx, call->event.type, 1, regs,
1194 head, NULL);
1195 }
1196 NOKPROBE_SYMBOL(kprobe_perf_func);
1197
1198 /* Kretprobe profile handler */
1199 static void
1200 kretprobe_perf_func(struct trace_kprobe *tk, struct kretprobe_instance *ri,
1201 struct pt_regs *regs)
1202 {
1203 struct trace_event_call *call = &tk->tp.call;
1204 struct bpf_prog *prog = call->prog;
1205 struct kretprobe_trace_entry_head *entry;
1206 struct hlist_head *head;
1207 int size, __size, dsize;
1208 int rctx;
1209
1210 if (prog && !trace_call_bpf(prog, regs))
1211 return;
1212
1213 head = this_cpu_ptr(call->perf_events);
1214 if (hlist_empty(head))
1215 return;
1216
1217 dsize = __get_data_size(&tk->tp, regs);
1218 __size = sizeof(*entry) + tk->tp.size + dsize;
1219 size = ALIGN(__size + sizeof(u32), sizeof(u64));
1220 size -= sizeof(u32);
1221
1222 entry = perf_trace_buf_alloc(size, NULL, &rctx);
1223 if (!entry)
1224 return;
1225
1226 entry->func = (unsigned long)tk->rp.kp.addr;
1227 entry->ret_ip = (unsigned long)ri->ret_addr;
1228 store_trace_args(sizeof(*entry), &tk->tp, regs, (u8 *)&entry[1], dsize);
1229 perf_trace_buf_submit(entry, size, rctx, call->event.type, 1, regs,
1230 head, NULL);
1231 }
1232 NOKPROBE_SYMBOL(kretprobe_perf_func);
1233 #endif /* CONFIG_PERF_EVENTS */
1234
1235 /*
1236 * called by perf_trace_init() or __ftrace_set_clr_event() under event_mutex.
1237 *
1238 * kprobe_trace_self_tests_init() does enable_trace_probe/disable_trace_probe
1239 * lockless, but we can't race with this __init function.
1240 */
1241 static int kprobe_register(struct trace_event_call *event,
1242 enum trace_reg type, void *data)
1243 {
1244 struct trace_kprobe *tk = (struct trace_kprobe *)event->data;
1245 struct trace_event_file *file = data;
1246
1247 switch (type) {
1248 case TRACE_REG_REGISTER:
1249 return enable_trace_kprobe(tk, file);
1250 case TRACE_REG_UNREGISTER:
1251 return disable_trace_kprobe(tk, file);
1252
1253 #ifdef CONFIG_PERF_EVENTS
1254 case TRACE_REG_PERF_REGISTER:
1255 return enable_trace_kprobe(tk, NULL);
1256 case TRACE_REG_PERF_UNREGISTER:
1257 return disable_trace_kprobe(tk, NULL);
1258 case TRACE_REG_PERF_OPEN:
1259 case TRACE_REG_PERF_CLOSE:
1260 case TRACE_REG_PERF_ADD:
1261 case TRACE_REG_PERF_DEL:
1262 return 0;
1263 #endif
1264 }
1265 return 0;
1266 }
1267
1268 static int kprobe_dispatcher(struct kprobe *kp, struct pt_regs *regs)
1269 {
1270 struct trace_kprobe *tk = container_of(kp, struct trace_kprobe, rp.kp);
1271
1272 raw_cpu_inc(*tk->nhit);
1273
1274 if (tk->tp.flags & TP_FLAG_TRACE)
1275 kprobe_trace_func(tk, regs);
1276 #ifdef CONFIG_PERF_EVENTS
1277 if (tk->tp.flags & TP_FLAG_PROFILE)
1278 kprobe_perf_func(tk, regs);
1279 #endif
1280 return 0; /* We don't tweek kernel, so just return 0 */
1281 }
1282 NOKPROBE_SYMBOL(kprobe_dispatcher);
1283
1284 static int
1285 kretprobe_dispatcher(struct kretprobe_instance *ri, struct pt_regs *regs)
1286 {
1287 struct trace_kprobe *tk = container_of(ri->rp, struct trace_kprobe, rp);
1288
1289 raw_cpu_inc(*tk->nhit);
1290
1291 if (tk->tp.flags & TP_FLAG_TRACE)
1292 kretprobe_trace_func(tk, ri, regs);
1293 #ifdef CONFIG_PERF_EVENTS
1294 if (tk->tp.flags & TP_FLAG_PROFILE)
1295 kretprobe_perf_func(tk, ri, regs);
1296 #endif
1297 return 0; /* We don't tweek kernel, so just return 0 */
1298 }
1299 NOKPROBE_SYMBOL(kretprobe_dispatcher);
1300
1301 static struct trace_event_functions kretprobe_funcs = {
1302 .trace = print_kretprobe_event
1303 };
1304
1305 static struct trace_event_functions kprobe_funcs = {
1306 .trace = print_kprobe_event
1307 };
1308
1309 static int register_kprobe_event(struct trace_kprobe *tk)
1310 {
1311 struct trace_event_call *call = &tk->tp.call;
1312 int ret;
1313
1314 /* Initialize trace_event_call */
1315 INIT_LIST_HEAD(&call->class->fields);
1316 if (trace_kprobe_is_return(tk)) {
1317 call->event.funcs = &kretprobe_funcs;
1318 call->class->define_fields = kretprobe_event_define_fields;
1319 } else {
1320 call->event.funcs = &kprobe_funcs;
1321 call->class->define_fields = kprobe_event_define_fields;
1322 }
1323 if (set_print_fmt(&tk->tp, trace_kprobe_is_return(tk)) < 0)
1324 return -ENOMEM;
1325 ret = register_trace_event(&call->event);
1326 if (!ret) {
1327 kfree(call->print_fmt);
1328 return -ENODEV;
1329 }
1330 call->flags = TRACE_EVENT_FL_KPROBE;
1331 call->class->reg = kprobe_register;
1332 call->data = tk;
1333 ret = trace_add_event_call(call);
1334 if (ret) {
1335 pr_info("Failed to register kprobe event: %s\n",
1336 trace_event_name(call));
1337 kfree(call->print_fmt);
1338 unregister_trace_event(&call->event);
1339 }
1340 return ret;
1341 }
1342
1343 static int unregister_kprobe_event(struct trace_kprobe *tk)
1344 {
1345 int ret;
1346
1347 /* tp->event is unregistered in trace_remove_event_call() */
1348 ret = trace_remove_event_call(&tk->tp.call);
1349 if (!ret)
1350 kfree(tk->tp.call.print_fmt);
1351 return ret;
1352 }
1353
1354 /* Make a tracefs interface for controlling probe points */
1355 static __init int init_kprobe_trace(void)
1356 {
1357 struct dentry *d_tracer;
1358 struct dentry *entry;
1359
1360 if (register_module_notifier(&trace_kprobe_module_nb))
1361 return -EINVAL;
1362
1363 d_tracer = tracing_init_dentry();
1364 if (IS_ERR(d_tracer))
1365 return 0;
1366
1367 entry = tracefs_create_file("kprobe_events", 0644, d_tracer,
1368 NULL, &kprobe_events_ops);
1369
1370 /* Event list interface */
1371 if (!entry)
1372 pr_warn("Could not create tracefs 'kprobe_events' entry\n");
1373
1374 /* Profile interface */
1375 entry = tracefs_create_file("kprobe_profile", 0444, d_tracer,
1376 NULL, &kprobe_profile_ops);
1377
1378 if (!entry)
1379 pr_warn("Could not create tracefs 'kprobe_profile' entry\n");
1380 return 0;
1381 }
1382 fs_initcall(init_kprobe_trace);
1383
1384
1385 #ifdef CONFIG_FTRACE_STARTUP_TEST
1386 /*
1387 * The "__used" keeps gcc from removing the function symbol
1388 * from the kallsyms table. 'noinline' makes sure that there
1389 * isn't an inlined version used by the test method below
1390 */
1391 static __used __init noinline int
1392 kprobe_trace_selftest_target(int a1, int a2, int a3, int a4, int a5, int a6)
1393 {
1394 return a1 + a2 + a3 + a4 + a5 + a6;
1395 }
1396
1397 static __init struct trace_event_file *
1398 find_trace_probe_file(struct trace_kprobe *tk, struct trace_array *tr)
1399 {
1400 struct trace_event_file *file;
1401
1402 list_for_each_entry(file, &tr->events, list)
1403 if (file->event_call == &tk->tp.call)
1404 return file;
1405
1406 return NULL;
1407 }
1408
1409 /*
1410 * Nobody but us can call enable_trace_kprobe/disable_trace_kprobe at this
1411 * stage, we can do this lockless.
1412 */
1413 static __init int kprobe_trace_self_tests_init(void)
1414 {
1415 int ret, warn = 0;
1416 int (*target)(int, int, int, int, int, int);
1417 struct trace_kprobe *tk;
1418 struct trace_event_file *file;
1419
1420 if (tracing_is_disabled())
1421 return -ENODEV;
1422
1423 target = kprobe_trace_selftest_target;
1424
1425 pr_info("Testing kprobe tracing: ");
1426
1427 ret = traceprobe_command("p:testprobe kprobe_trace_selftest_target "
1428 "$stack $stack0 +0($stack)",
1429 create_trace_kprobe);
1430 if (WARN_ON_ONCE(ret)) {
1431 pr_warn("error on probing function entry.\n");
1432 warn++;
1433 } else {
1434 /* Enable trace point */
1435 tk = find_trace_kprobe("testprobe", KPROBE_EVENT_SYSTEM);
1436 if (WARN_ON_ONCE(tk == NULL)) {
1437 pr_warn("error on getting new probe.\n");
1438 warn++;
1439 } else {
1440 file = find_trace_probe_file(tk, top_trace_array());
1441 if (WARN_ON_ONCE(file == NULL)) {
1442 pr_warn("error on getting probe file.\n");
1443 warn++;
1444 } else
1445 enable_trace_kprobe(tk, file);
1446 }
1447 }
1448
1449 ret = traceprobe_command("r:testprobe2 kprobe_trace_selftest_target "
1450 "$retval", create_trace_kprobe);
1451 if (WARN_ON_ONCE(ret)) {
1452 pr_warn("error on probing function return.\n");
1453 warn++;
1454 } else {
1455 /* Enable trace point */
1456 tk = find_trace_kprobe("testprobe2", KPROBE_EVENT_SYSTEM);
1457 if (WARN_ON_ONCE(tk == NULL)) {
1458 pr_warn("error on getting 2nd new probe.\n");
1459 warn++;
1460 } else {
1461 file = find_trace_probe_file(tk, top_trace_array());
1462 if (WARN_ON_ONCE(file == NULL)) {
1463 pr_warn("error on getting probe file.\n");
1464 warn++;
1465 } else
1466 enable_trace_kprobe(tk, file);
1467 }
1468 }
1469
1470 if (warn)
1471 goto end;
1472
1473 ret = target(1, 2, 3, 4, 5, 6);
1474
1475 /*
1476 * Not expecting an error here, the check is only to prevent the
1477 * optimizer from removing the call to target() as otherwise there
1478 * are no side-effects and the call is never performed.
1479 */
1480 if (ret != 21)
1481 warn++;
1482
1483 /* Disable trace points before removing it */
1484 tk = find_trace_kprobe("testprobe", KPROBE_EVENT_SYSTEM);
1485 if (WARN_ON_ONCE(tk == NULL)) {
1486 pr_warn("error on getting test probe.\n");
1487 warn++;
1488 } else {
1489 if (trace_kprobe_nhit(tk) != 1) {
1490 pr_warn("incorrect number of testprobe hits\n");
1491 warn++;
1492 }
1493
1494 file = find_trace_probe_file(tk, top_trace_array());
1495 if (WARN_ON_ONCE(file == NULL)) {
1496 pr_warn("error on getting probe file.\n");
1497 warn++;
1498 } else
1499 disable_trace_kprobe(tk, file);
1500 }
1501
1502 tk = find_trace_kprobe("testprobe2", KPROBE_EVENT_SYSTEM);
1503 if (WARN_ON_ONCE(tk == NULL)) {
1504 pr_warn("error on getting 2nd test probe.\n");
1505 warn++;
1506 } else {
1507 if (trace_kprobe_nhit(tk) != 1) {
1508 pr_warn("incorrect number of testprobe2 hits\n");
1509 warn++;
1510 }
1511
1512 file = find_trace_probe_file(tk, top_trace_array());
1513 if (WARN_ON_ONCE(file == NULL)) {
1514 pr_warn("error on getting probe file.\n");
1515 warn++;
1516 } else
1517 disable_trace_kprobe(tk, file);
1518 }
1519
1520 ret = traceprobe_command("-:testprobe", create_trace_kprobe);
1521 if (WARN_ON_ONCE(ret)) {
1522 pr_warn("error on deleting a probe.\n");
1523 warn++;
1524 }
1525
1526 ret = traceprobe_command("-:testprobe2", create_trace_kprobe);
1527 if (WARN_ON_ONCE(ret)) {
1528 pr_warn("error on deleting a probe.\n");
1529 warn++;
1530 }
1531
1532 end:
1533 release_all_trace_kprobes();
1534 /*
1535 * Wait for the optimizer work to finish. Otherwise it might fiddle
1536 * with probes in already freed __init text.
1537 */
1538 wait_for_kprobe_optimizer();
1539 if (warn)
1540 pr_cont("NG: Some tests are failed. Please check them.\n");
1541 else
1542 pr_cont("OK\n");
1543 return 0;
1544 }
1545
1546 late_initcall(kprobe_trace_self_tests_init);
1547
1548 #endif
Linux with added FPC-III support