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