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[GitHub/LineageOS/android_kernel_motorola_exynos9610.git] / kernel / trace / trace_kprobe.c
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 if (isdigit(argv[1][0])) {
711 /* an address specified */
712 ret = kstrtoul(&argv[1][0], 0, (unsigned long *)&addr);
713 if (ret) {
714 pr_info("Failed to parse address.\n");
715 return ret;
716 }
717 } else {
718 /* a symbol specified */
719 symbol = argv[1];
720 /* TODO: support .init module functions */
721 ret = traceprobe_split_symbol_offset(symbol, &offset);
722 if (ret) {
723 pr_info("Failed to parse symbol.\n");
724 return ret;
725 }
726 if (offset && is_return &&
727 !function_offset_within_entry(NULL, symbol, offset)) {
728 pr_info("Given offset is not valid for return probe.\n");
729 return -EINVAL;
730 }
731 }
732 argc -= 2; argv += 2;
733
734 /* setup a probe */
735 if (!event) {
736 /* Make a new event name */
737 if (symbol)
738 snprintf(buf, MAX_EVENT_NAME_LEN, "%c_%s_%ld",
739 is_return ? 'r' : 'p', symbol, offset);
740 else
741 snprintf(buf, MAX_EVENT_NAME_LEN, "%c_0x%p",
742 is_return ? 'r' : 'p', addr);
743 event = buf;
744 }
745 tk = alloc_trace_kprobe(group, event, addr, symbol, offset, maxactive,
746 argc, is_return);
747 if (IS_ERR(tk)) {
748 pr_info("Failed to allocate trace_probe.(%d)\n",
749 (int)PTR_ERR(tk));
750 return PTR_ERR(tk);
751 }
752
753 /* parse arguments */
754 ret = 0;
755 for (i = 0; i < argc && i < MAX_TRACE_ARGS; i++) {
756 struct probe_arg *parg = &tk->tp.args[i];
757
758 /* Increment count for freeing args in error case */
759 tk->tp.nr_args++;
760
761 /* Parse argument name */
762 arg = strchr(argv[i], '=');
763 if (arg) {
764 *arg++ = '\0';
765 parg->name = kstrdup(argv[i], GFP_KERNEL);
766 } else {
767 arg = argv[i];
768 /* If argument name is omitted, set "argN" */
769 snprintf(buf, MAX_EVENT_NAME_LEN, "arg%d", i + 1);
770 parg->name = kstrdup(buf, GFP_KERNEL);
771 }
772
773 if (!parg->name) {
774 pr_info("Failed to allocate argument[%d] name.\n", i);
775 ret = -ENOMEM;
776 goto error;
777 }
778
779 if (!is_good_name(parg->name)) {
780 pr_info("Invalid argument[%d] name: %s\n",
781 i, parg->name);
782 ret = -EINVAL;
783 goto error;
784 }
785
786 if (traceprobe_conflict_field_name(parg->name,
787 tk->tp.args, i)) {
788 pr_info("Argument[%d] name '%s' conflicts with "
789 "another field.\n", i, argv[i]);
790 ret = -EINVAL;
791 goto error;
792 }
793
794 /* Parse fetch argument */
795 ret = traceprobe_parse_probe_arg(arg, &tk->tp.size, parg,
796 is_return, true,
797 kprobes_fetch_type_table);
798 if (ret) {
799 pr_info("Parse error at argument[%d]. (%d)\n", i, ret);
800 goto error;
801 }
802 }
803
804 ret = register_trace_kprobe(tk);
805 if (ret)
806 goto error;
807 return 0;
808
809 error:
810 free_trace_kprobe(tk);
811 return ret;
812 }
813
814 static int release_all_trace_kprobes(void)
815 {
816 struct trace_kprobe *tk;
817 int ret = 0;
818
819 mutex_lock(&probe_lock);
820 /* Ensure no probe is in use. */
821 list_for_each_entry(tk, &probe_list, list)
822 if (trace_probe_is_enabled(&tk->tp)) {
823 ret = -EBUSY;
824 goto end;
825 }
826 /* TODO: Use batch unregistration */
827 while (!list_empty(&probe_list)) {
828 tk = list_entry(probe_list.next, struct trace_kprobe, list);
829 ret = unregister_trace_kprobe(tk);
830 if (ret)
831 goto end;
832 free_trace_kprobe(tk);
833 }
834
835 end:
836 mutex_unlock(&probe_lock);
837
838 return ret;
839 }
840
841 /* Probes listing interfaces */
842 static void *probes_seq_start(struct seq_file *m, loff_t *pos)
843 {
844 mutex_lock(&probe_lock);
845 return seq_list_start(&probe_list, *pos);
846 }
847
848 static void *probes_seq_next(struct seq_file *m, void *v, loff_t *pos)
849 {
850 return seq_list_next(v, &probe_list, pos);
851 }
852
853 static void probes_seq_stop(struct seq_file *m, void *v)
854 {
855 mutex_unlock(&probe_lock);
856 }
857
858 static int probes_seq_show(struct seq_file *m, void *v)
859 {
860 struct trace_kprobe *tk = v;
861 int i;
862
863 seq_putc(m, trace_kprobe_is_return(tk) ? 'r' : 'p');
864 seq_printf(m, ":%s/%s", tk->tp.call.class->system,
865 trace_event_name(&tk->tp.call));
866
867 if (!tk->symbol)
868 seq_printf(m, " 0x%p", tk->rp.kp.addr);
869 else if (tk->rp.kp.offset)
870 seq_printf(m, " %s+%u", trace_kprobe_symbol(tk),
871 tk->rp.kp.offset);
872 else
873 seq_printf(m, " %s", trace_kprobe_symbol(tk));
874
875 for (i = 0; i < tk->tp.nr_args; i++)
876 seq_printf(m, " %s=%s", tk->tp.args[i].name, tk->tp.args[i].comm);
877 seq_putc(m, '\n');
878
879 return 0;
880 }
881
882 static const struct seq_operations probes_seq_op = {
883 .start = probes_seq_start,
884 .next = probes_seq_next,
885 .stop = probes_seq_stop,
886 .show = probes_seq_show
887 };
888
889 static int probes_open(struct inode *inode, struct file *file)
890 {
891 int ret;
892
893 if ((file->f_mode & FMODE_WRITE) && (file->f_flags & O_TRUNC)) {
894 ret = release_all_trace_kprobes();
895 if (ret < 0)
896 return ret;
897 }
898
899 return seq_open(file, &probes_seq_op);
900 }
901
902 static ssize_t probes_write(struct file *file, const char __user *buffer,
903 size_t count, loff_t *ppos)
904 {
905 return traceprobe_probes_write(file, buffer, count, ppos,
906 create_trace_kprobe);
907 }
908
909 static const struct file_operations kprobe_events_ops = {
910 .owner = THIS_MODULE,
911 .open = probes_open,
912 .read = seq_read,
913 .llseek = seq_lseek,
914 .release = seq_release,
915 .write = probes_write,
916 };
917
918 /* Probes profiling interfaces */
919 static int probes_profile_seq_show(struct seq_file *m, void *v)
920 {
921 struct trace_kprobe *tk = v;
922
923 seq_printf(m, " %-44s %15lu %15lu\n",
924 trace_event_name(&tk->tp.call),
925 trace_kprobe_nhit(tk),
926 tk->rp.kp.nmissed);
927
928 return 0;
929 }
930
931 static const struct seq_operations profile_seq_op = {
932 .start = probes_seq_start,
933 .next = probes_seq_next,
934 .stop = probes_seq_stop,
935 .show = probes_profile_seq_show
936 };
937
938 static int profile_open(struct inode *inode, struct file *file)
939 {
940 return seq_open(file, &profile_seq_op);
941 }
942
943 static const struct file_operations kprobe_profile_ops = {
944 .owner = THIS_MODULE,
945 .open = profile_open,
946 .read = seq_read,
947 .llseek = seq_lseek,
948 .release = seq_release,
949 };
950
951 /* Kprobe handler */
952 static nokprobe_inline void
953 __kprobe_trace_func(struct trace_kprobe *tk, struct pt_regs *regs,
954 struct trace_event_file *trace_file)
955 {
956 struct kprobe_trace_entry_head *entry;
957 struct ring_buffer_event *event;
958 struct ring_buffer *buffer;
959 int size, dsize, pc;
960 unsigned long irq_flags;
961 struct trace_event_call *call = &tk->tp.call;
962
963 WARN_ON(call != trace_file->event_call);
964
965 if (trace_trigger_soft_disabled(trace_file))
966 return;
967
968 local_save_flags(irq_flags);
969 pc = preempt_count();
970
971 dsize = __get_data_size(&tk->tp, regs);
972 size = sizeof(*entry) + tk->tp.size + dsize;
973
974 event = trace_event_buffer_lock_reserve(&buffer, trace_file,
975 call->event.type,
976 size, irq_flags, pc);
977 if (!event)
978 return;
979
980 entry = ring_buffer_event_data(event);
981 entry->ip = (unsigned long)tk->rp.kp.addr;
982 store_trace_args(sizeof(*entry), &tk->tp, regs, (u8 *)&entry[1], dsize);
983
984 event_trigger_unlock_commit_regs(trace_file, buffer, event,
985 entry, irq_flags, pc, regs);
986 }
987
988 static void
989 kprobe_trace_func(struct trace_kprobe *tk, struct pt_regs *regs)
990 {
991 struct event_file_link *link;
992
993 list_for_each_entry_rcu(link, &tk->tp.files, list)
994 __kprobe_trace_func(tk, regs, link->file);
995 }
996 NOKPROBE_SYMBOL(kprobe_trace_func);
997
998 /* Kretprobe handler */
999 static nokprobe_inline void
1000 __kretprobe_trace_func(struct trace_kprobe *tk, struct kretprobe_instance *ri,
1001 struct pt_regs *regs,
1002 struct trace_event_file *trace_file)
1003 {
1004 struct kretprobe_trace_entry_head *entry;
1005 struct ring_buffer_event *event;
1006 struct ring_buffer *buffer;
1007 int size, pc, dsize;
1008 unsigned long irq_flags;
1009 struct trace_event_call *call = &tk->tp.call;
1010
1011 WARN_ON(call != trace_file->event_call);
1012
1013 if (trace_trigger_soft_disabled(trace_file))
1014 return;
1015
1016 local_save_flags(irq_flags);
1017 pc = preempt_count();
1018
1019 dsize = __get_data_size(&tk->tp, regs);
1020 size = sizeof(*entry) + tk->tp.size + dsize;
1021
1022 event = trace_event_buffer_lock_reserve(&buffer, trace_file,
1023 call->event.type,
1024 size, irq_flags, pc);
1025 if (!event)
1026 return;
1027
1028 entry = ring_buffer_event_data(event);
1029 entry->func = (unsigned long)tk->rp.kp.addr;
1030 entry->ret_ip = (unsigned long)ri->ret_addr;
1031 store_trace_args(sizeof(*entry), &tk->tp, regs, (u8 *)&entry[1], dsize);
1032
1033 event_trigger_unlock_commit_regs(trace_file, buffer, event,
1034 entry, irq_flags, pc, regs);
1035 }
1036
1037 static void
1038 kretprobe_trace_func(struct trace_kprobe *tk, struct kretprobe_instance *ri,
1039 struct pt_regs *regs)
1040 {
1041 struct event_file_link *link;
1042
1043 list_for_each_entry_rcu(link, &tk->tp.files, list)
1044 __kretprobe_trace_func(tk, ri, regs, link->file);
1045 }
1046 NOKPROBE_SYMBOL(kretprobe_trace_func);
1047
1048 /* Event entry printers */
1049 static enum print_line_t
1050 print_kprobe_event(struct trace_iterator *iter, int flags,
1051 struct trace_event *event)
1052 {
1053 struct kprobe_trace_entry_head *field;
1054 struct trace_seq *s = &iter->seq;
1055 struct trace_probe *tp;
1056 u8 *data;
1057 int i;
1058
1059 field = (struct kprobe_trace_entry_head *)iter->ent;
1060 tp = container_of(event, struct trace_probe, call.event);
1061
1062 trace_seq_printf(s, "%s: (", trace_event_name(&tp->call));
1063
1064 if (!seq_print_ip_sym(s, field->ip, flags | TRACE_ITER_SYM_OFFSET))
1065 goto out;
1066
1067 trace_seq_putc(s, ')');
1068
1069 data = (u8 *)&field[1];
1070 for (i = 0; i < tp->nr_args; i++)
1071 if (!tp->args[i].type->print(s, tp->args[i].name,
1072 data + tp->args[i].offset, field))
1073 goto out;
1074
1075 trace_seq_putc(s, '\n');
1076 out:
1077 return trace_handle_return(s);
1078 }
1079
1080 static enum print_line_t
1081 print_kretprobe_event(struct trace_iterator *iter, int flags,
1082 struct trace_event *event)
1083 {
1084 struct kretprobe_trace_entry_head *field;
1085 struct trace_seq *s = &iter->seq;
1086 struct trace_probe *tp;
1087 u8 *data;
1088 int i;
1089
1090 field = (struct kretprobe_trace_entry_head *)iter->ent;
1091 tp = container_of(event, struct trace_probe, call.event);
1092
1093 trace_seq_printf(s, "%s: (", trace_event_name(&tp->call));
1094
1095 if (!seq_print_ip_sym(s, field->ret_ip, flags | TRACE_ITER_SYM_OFFSET))
1096 goto out;
1097
1098 trace_seq_puts(s, " <- ");
1099
1100 if (!seq_print_ip_sym(s, field->func, flags & ~TRACE_ITER_SYM_OFFSET))
1101 goto out;
1102
1103 trace_seq_putc(s, ')');
1104
1105 data = (u8 *)&field[1];
1106 for (i = 0; i < tp->nr_args; i++)
1107 if (!tp->args[i].type->print(s, tp->args[i].name,
1108 data + tp->args[i].offset, field))
1109 goto out;
1110
1111 trace_seq_putc(s, '\n');
1112
1113 out:
1114 return trace_handle_return(s);
1115 }
1116
1117
1118 static int kprobe_event_define_fields(struct trace_event_call *event_call)
1119 {
1120 int ret, i;
1121 struct kprobe_trace_entry_head field;
1122 struct trace_kprobe *tk = (struct trace_kprobe *)event_call->data;
1123
1124 DEFINE_FIELD(unsigned long, ip, FIELD_STRING_IP, 0);
1125 /* Set argument names as fields */
1126 for (i = 0; i < tk->tp.nr_args; i++) {
1127 struct probe_arg *parg = &tk->tp.args[i];
1128
1129 ret = trace_define_field(event_call, parg->type->fmttype,
1130 parg->name,
1131 sizeof(field) + parg->offset,
1132 parg->type->size,
1133 parg->type->is_signed,
1134 FILTER_OTHER);
1135 if (ret)
1136 return ret;
1137 }
1138 return 0;
1139 }
1140
1141 static int kretprobe_event_define_fields(struct trace_event_call *event_call)
1142 {
1143 int ret, i;
1144 struct kretprobe_trace_entry_head field;
1145 struct trace_kprobe *tk = (struct trace_kprobe *)event_call->data;
1146
1147 DEFINE_FIELD(unsigned long, func, FIELD_STRING_FUNC, 0);
1148 DEFINE_FIELD(unsigned long, ret_ip, FIELD_STRING_RETIP, 0);
1149 /* Set argument names as fields */
1150 for (i = 0; i < tk->tp.nr_args; i++) {
1151 struct probe_arg *parg = &tk->tp.args[i];
1152
1153 ret = trace_define_field(event_call, parg->type->fmttype,
1154 parg->name,
1155 sizeof(field) + parg->offset,
1156 parg->type->size,
1157 parg->type->is_signed,
1158 FILTER_OTHER);
1159 if (ret)
1160 return ret;
1161 }
1162 return 0;
1163 }
1164
1165 #ifdef CONFIG_PERF_EVENTS
1166
1167 /* Kprobe profile handler */
1168 static void
1169 kprobe_perf_func(struct trace_kprobe *tk, struct pt_regs *regs)
1170 {
1171 struct trace_event_call *call = &tk->tp.call;
1172 struct bpf_prog *prog = call->prog;
1173 struct kprobe_trace_entry_head *entry;
1174 struct hlist_head *head;
1175 int size, __size, dsize;
1176 int rctx;
1177
1178 if (prog && !trace_call_bpf(prog, regs))
1179 return;
1180
1181 head = this_cpu_ptr(call->perf_events);
1182 if (hlist_empty(head))
1183 return;
1184
1185 dsize = __get_data_size(&tk->tp, regs);
1186 __size = sizeof(*entry) + tk->tp.size + dsize;
1187 size = ALIGN(__size + sizeof(u32), sizeof(u64));
1188 size -= sizeof(u32);
1189
1190 entry = perf_trace_buf_alloc(size, NULL, &rctx);
1191 if (!entry)
1192 return;
1193
1194 entry->ip = (unsigned long)tk->rp.kp.addr;
1195 memset(&entry[1], 0, dsize);
1196 store_trace_args(sizeof(*entry), &tk->tp, regs, (u8 *)&entry[1], dsize);
1197 perf_trace_buf_submit(entry, size, rctx, call->event.type, 1, regs,
1198 head, NULL);
1199 }
1200 NOKPROBE_SYMBOL(kprobe_perf_func);
1201
1202 /* Kretprobe profile handler */
1203 static void
1204 kretprobe_perf_func(struct trace_kprobe *tk, struct kretprobe_instance *ri,
1205 struct pt_regs *regs)
1206 {
1207 struct trace_event_call *call = &tk->tp.call;
1208 struct bpf_prog *prog = call->prog;
1209 struct kretprobe_trace_entry_head *entry;
1210 struct hlist_head *head;
1211 int size, __size, dsize;
1212 int rctx;
1213
1214 if (prog && !trace_call_bpf(prog, regs))
1215 return;
1216
1217 head = this_cpu_ptr(call->perf_events);
1218 if (hlist_empty(head))
1219 return;
1220
1221 dsize = __get_data_size(&tk->tp, regs);
1222 __size = sizeof(*entry) + tk->tp.size + dsize;
1223 size = ALIGN(__size + sizeof(u32), sizeof(u64));
1224 size -= sizeof(u32);
1225
1226 entry = perf_trace_buf_alloc(size, NULL, &rctx);
1227 if (!entry)
1228 return;
1229
1230 entry->func = (unsigned long)tk->rp.kp.addr;
1231 entry->ret_ip = (unsigned long)ri->ret_addr;
1232 store_trace_args(sizeof(*entry), &tk->tp, regs, (u8 *)&entry[1], dsize);
1233 perf_trace_buf_submit(entry, size, rctx, call->event.type, 1, regs,
1234 head, NULL);
1235 }
1236 NOKPROBE_SYMBOL(kretprobe_perf_func);
1237 #endif /* CONFIG_PERF_EVENTS */
1238
1239 /*
1240 * called by perf_trace_init() or __ftrace_set_clr_event() under event_mutex.
1241 *
1242 * kprobe_trace_self_tests_init() does enable_trace_probe/disable_trace_probe
1243 * lockless, but we can't race with this __init function.
1244 */
1245 static int kprobe_register(struct trace_event_call *event,
1246 enum trace_reg type, void *data)
1247 {
1248 struct trace_kprobe *tk = (struct trace_kprobe *)event->data;
1249 struct trace_event_file *file = data;
1250
1251 switch (type) {
1252 case TRACE_REG_REGISTER:
1253 return enable_trace_kprobe(tk, file);
1254 case TRACE_REG_UNREGISTER:
1255 return disable_trace_kprobe(tk, file);
1256
1257 #ifdef CONFIG_PERF_EVENTS
1258 case TRACE_REG_PERF_REGISTER:
1259 return enable_trace_kprobe(tk, NULL);
1260 case TRACE_REG_PERF_UNREGISTER:
1261 return disable_trace_kprobe(tk, NULL);
1262 case TRACE_REG_PERF_OPEN:
1263 case TRACE_REG_PERF_CLOSE:
1264 case TRACE_REG_PERF_ADD:
1265 case TRACE_REG_PERF_DEL:
1266 return 0;
1267 #endif
1268 }
1269 return 0;
1270 }
1271
1272 static int kprobe_dispatcher(struct kprobe *kp, struct pt_regs *regs)
1273 {
1274 struct trace_kprobe *tk = container_of(kp, struct trace_kprobe, rp.kp);
1275
1276 raw_cpu_inc(*tk->nhit);
1277
1278 if (tk->tp.flags & TP_FLAG_TRACE)
1279 kprobe_trace_func(tk, regs);
1280 #ifdef CONFIG_PERF_EVENTS
1281 if (tk->tp.flags & TP_FLAG_PROFILE)
1282 kprobe_perf_func(tk, regs);
1283 #endif
1284 return 0; /* We don't tweek kernel, so just return 0 */
1285 }
1286 NOKPROBE_SYMBOL(kprobe_dispatcher);
1287
1288 static int
1289 kretprobe_dispatcher(struct kretprobe_instance *ri, struct pt_regs *regs)
1290 {
1291 struct trace_kprobe *tk = container_of(ri->rp, struct trace_kprobe, rp);
1292
1293 raw_cpu_inc(*tk->nhit);
1294
1295 if (tk->tp.flags & TP_FLAG_TRACE)
1296 kretprobe_trace_func(tk, ri, regs);
1297 #ifdef CONFIG_PERF_EVENTS
1298 if (tk->tp.flags & TP_FLAG_PROFILE)
1299 kretprobe_perf_func(tk, ri, regs);
1300 #endif
1301 return 0; /* We don't tweek kernel, so just return 0 */
1302 }
1303 NOKPROBE_SYMBOL(kretprobe_dispatcher);
1304
1305 static struct trace_event_functions kretprobe_funcs = {
1306 .trace = print_kretprobe_event
1307 };
1308
1309 static struct trace_event_functions kprobe_funcs = {
1310 .trace = print_kprobe_event
1311 };
1312
1313 static int register_kprobe_event(struct trace_kprobe *tk)
1314 {
1315 struct trace_event_call *call = &tk->tp.call;
1316 int ret;
1317
1318 /* Initialize trace_event_call */
1319 INIT_LIST_HEAD(&call->class->fields);
1320 if (trace_kprobe_is_return(tk)) {
1321 call->event.funcs = &kretprobe_funcs;
1322 call->class->define_fields = kretprobe_event_define_fields;
1323 } else {
1324 call->event.funcs = &kprobe_funcs;
1325 call->class->define_fields = kprobe_event_define_fields;
1326 }
1327 if (set_print_fmt(&tk->tp, trace_kprobe_is_return(tk)) < 0)
1328 return -ENOMEM;
1329 ret = register_trace_event(&call->event);
1330 if (!ret) {
1331 kfree(call->print_fmt);
1332 return -ENODEV;
1333 }
1334 call->flags = TRACE_EVENT_FL_KPROBE;
1335 call->class->reg = kprobe_register;
1336 call->data = tk;
1337 ret = trace_add_event_call(call);
1338 if (ret) {
1339 pr_info("Failed to register kprobe event: %s\n",
1340 trace_event_name(call));
1341 kfree(call->print_fmt);
1342 unregister_trace_event(&call->event);
1343 }
1344 return ret;
1345 }
1346
1347 static int unregister_kprobe_event(struct trace_kprobe *tk)
1348 {
1349 int ret;
1350
1351 /* tp->event is unregistered in trace_remove_event_call() */
1352 ret = trace_remove_event_call(&tk->tp.call);
1353 if (!ret)
1354 kfree(tk->tp.call.print_fmt);
1355 return ret;
1356 }
1357
1358 /* Make a tracefs interface for controlling probe points */
1359 static __init int init_kprobe_trace(void)
1360 {
1361 struct dentry *d_tracer;
1362 struct dentry *entry;
1363
1364 if (register_module_notifier(&trace_kprobe_module_nb))
1365 return -EINVAL;
1366
1367 d_tracer = tracing_init_dentry();
1368 if (IS_ERR(d_tracer))
1369 return 0;
1370
1371 entry = tracefs_create_file("kprobe_events", 0644, d_tracer,
1372 NULL, &kprobe_events_ops);
1373
1374 /* Event list interface */
1375 if (!entry)
1376 pr_warn("Could not create tracefs 'kprobe_events' entry\n");
1377
1378 /* Profile interface */
1379 entry = tracefs_create_file("kprobe_profile", 0444, d_tracer,
1380 NULL, &kprobe_profile_ops);
1381
1382 if (!entry)
1383 pr_warn("Could not create tracefs 'kprobe_profile' entry\n");
1384 return 0;
1385 }
1386 fs_initcall(init_kprobe_trace);
1387
1388
1389 #ifdef CONFIG_FTRACE_STARTUP_TEST
1390 /*
1391 * The "__used" keeps gcc from removing the function symbol
1392 * from the kallsyms table. 'noinline' makes sure that there
1393 * isn't an inlined version used by the test method below
1394 */
1395 static __used __init noinline int
1396 kprobe_trace_selftest_target(int a1, int a2, int a3, int a4, int a5, int a6)
1397 {
1398 return a1 + a2 + a3 + a4 + a5 + a6;
1399 }
1400
1401 static __init struct trace_event_file *
1402 find_trace_probe_file(struct trace_kprobe *tk, struct trace_array *tr)
1403 {
1404 struct trace_event_file *file;
1405
1406 list_for_each_entry(file, &tr->events, list)
1407 if (file->event_call == &tk->tp.call)
1408 return file;
1409
1410 return NULL;
1411 }
1412
1413 /*
1414 * Nobody but us can call enable_trace_kprobe/disable_trace_kprobe at this
1415 * stage, we can do this lockless.
1416 */
1417 static __init int kprobe_trace_self_tests_init(void)
1418 {
1419 int ret, warn = 0;
1420 int (*target)(int, int, int, int, int, int);
1421 struct trace_kprobe *tk;
1422 struct trace_event_file *file;
1423
1424 if (tracing_is_disabled())
1425 return -ENODEV;
1426
1427 target = kprobe_trace_selftest_target;
1428
1429 pr_info("Testing kprobe tracing: ");
1430
1431 ret = traceprobe_command("p:testprobe kprobe_trace_selftest_target "
1432 "$stack $stack0 +0($stack)",
1433 create_trace_kprobe);
1434 if (WARN_ON_ONCE(ret)) {
1435 pr_warn("error on probing function entry.\n");
1436 warn++;
1437 } else {
1438 /* Enable trace point */
1439 tk = find_trace_kprobe("testprobe", KPROBE_EVENT_SYSTEM);
1440 if (WARN_ON_ONCE(tk == NULL)) {
1441 pr_warn("error on getting new probe.\n");
1442 warn++;
1443 } else {
1444 file = find_trace_probe_file(tk, top_trace_array());
1445 if (WARN_ON_ONCE(file == NULL)) {
1446 pr_warn("error on getting probe file.\n");
1447 warn++;
1448 } else
1449 enable_trace_kprobe(tk, file);
1450 }
1451 }
1452
1453 ret = traceprobe_command("r:testprobe2 kprobe_trace_selftest_target "
1454 "$retval", create_trace_kprobe);
1455 if (WARN_ON_ONCE(ret)) {
1456 pr_warn("error on probing function return.\n");
1457 warn++;
1458 } else {
1459 /* Enable trace point */
1460 tk = find_trace_kprobe("testprobe2", KPROBE_EVENT_SYSTEM);
1461 if (WARN_ON_ONCE(tk == NULL)) {
1462 pr_warn("error on getting 2nd new probe.\n");
1463 warn++;
1464 } else {
1465 file = find_trace_probe_file(tk, top_trace_array());
1466 if (WARN_ON_ONCE(file == NULL)) {
1467 pr_warn("error on getting probe file.\n");
1468 warn++;
1469 } else
1470 enable_trace_kprobe(tk, file);
1471 }
1472 }
1473
1474 if (warn)
1475 goto end;
1476
1477 ret = target(1, 2, 3, 4, 5, 6);
1478
1479 /*
1480 * Not expecting an error here, the check is only to prevent the
1481 * optimizer from removing the call to target() as otherwise there
1482 * are no side-effects and the call is never performed.
1483 */
1484 if (ret != 21)
1485 warn++;
1486
1487 /* Disable trace points before removing it */
1488 tk = find_trace_kprobe("testprobe", KPROBE_EVENT_SYSTEM);
1489 if (WARN_ON_ONCE(tk == NULL)) {
1490 pr_warn("error on getting test probe.\n");
1491 warn++;
1492 } else {
1493 if (trace_kprobe_nhit(tk) != 1) {
1494 pr_warn("incorrect number of testprobe hits\n");
1495 warn++;
1496 }
1497
1498 file = find_trace_probe_file(tk, top_trace_array());
1499 if (WARN_ON_ONCE(file == NULL)) {
1500 pr_warn("error on getting probe file.\n");
1501 warn++;
1502 } else
1503 disable_trace_kprobe(tk, file);
1504 }
1505
1506 tk = find_trace_kprobe("testprobe2", KPROBE_EVENT_SYSTEM);
1507 if (WARN_ON_ONCE(tk == NULL)) {
1508 pr_warn("error on getting 2nd test probe.\n");
1509 warn++;
1510 } else {
1511 if (trace_kprobe_nhit(tk) != 1) {
1512 pr_warn("incorrect number of testprobe2 hits\n");
1513 warn++;
1514 }
1515
1516 file = find_trace_probe_file(tk, top_trace_array());
1517 if (WARN_ON_ONCE(file == NULL)) {
1518 pr_warn("error on getting probe file.\n");
1519 warn++;
1520 } else
1521 disable_trace_kprobe(tk, file);
1522 }
1523
1524 ret = traceprobe_command("-:testprobe", create_trace_kprobe);
1525 if (WARN_ON_ONCE(ret)) {
1526 pr_warn("error on deleting a probe.\n");
1527 warn++;
1528 }
1529
1530 ret = traceprobe_command("-:testprobe2", create_trace_kprobe);
1531 if (WARN_ON_ONCE(ret)) {
1532 pr_warn("error on deleting a probe.\n");
1533 warn++;
1534 }
1535
1536 end:
1537 release_all_trace_kprobes();
1538 /*
1539 * Wait for the optimizer work to finish. Otherwise it might fiddle
1540 * with probes in already freed __init text.
1541 */
1542 wait_for_kprobe_optimizer();
1543 if (warn)
1544 pr_cont("NG: Some tests are failed. Please check them.\n");
1545 else
1546 pr_cont("OK\n");
1547 return 0;
1548 }
1549
1550 late_initcall(kprobe_trace_self_tests_init);
1551
1552 #endif