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perf tools: Don't clone maps from parent when synthesizing forks
[linux/fpc-iii.git] / kernel / trace / trace_kprobe.c
blobc30032367aab4a5c83a013d615830cda97a82f8a
1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * Kprobes-based tracing events
4 *
5 * Created by Masami Hiramatsu <mhiramat@redhat.com>
6 *
7 */
8 #define pr_fmt(fmt) "trace_kprobe: " fmt
9
10 #include <linux/module.h>
11 #include <linux/uaccess.h>
12 #include <linux/rculist.h>
13 #include <linux/error-injection.h>
14
15 #include "trace_kprobe_selftest.h"
16 #include "trace_probe.h"
17
18 #define KPROBE_EVENT_SYSTEM "kprobes"
19 #define KRETPROBE_MAXACTIVE_MAX 4096
20
21 /**
22 * Kprobe event core functions
23 */
24 struct trace_kprobe {
25 struct list_head list;
26 struct kretprobe rp; /* Use rp.kp for kprobe use */
27 unsigned long __percpu *nhit;
28 const char *symbol; /* symbol name */
29 struct trace_probe tp;
30 };
31
32 #define SIZEOF_TRACE_KPROBE(n) \
33 (offsetof(struct trace_kprobe, tp.args) + \
34 (sizeof(struct probe_arg) * (n)))
35
36 static nokprobe_inline bool trace_kprobe_is_return(struct trace_kprobe *tk)
37 {
38 return tk->rp.handler != NULL;
39 }
40
41 static nokprobe_inline const char *trace_kprobe_symbol(struct trace_kprobe *tk)
42 {
43 return tk->symbol ? tk->symbol : "unknown";
44 }
45
46 static nokprobe_inline unsigned long trace_kprobe_offset(struct trace_kprobe *tk)
47 {
48 return tk->rp.kp.offset;
49 }
50
51 static nokprobe_inline bool trace_kprobe_has_gone(struct trace_kprobe *tk)
52 {
53 return !!(kprobe_gone(&tk->rp.kp));
54 }
55
56 static nokprobe_inline bool trace_kprobe_within_module(struct trace_kprobe *tk,
57 struct module *mod)
58 {
59 int len = strlen(mod->name);
60 const char *name = trace_kprobe_symbol(tk);
61 return strncmp(mod->name, name, len) == 0 && name[len] == ':';
62 }
63
64 static nokprobe_inline bool trace_kprobe_is_on_module(struct trace_kprobe *tk)
65 {
66 return !!strchr(trace_kprobe_symbol(tk), ':');
67 }
68
69 static nokprobe_inline unsigned long trace_kprobe_nhit(struct trace_kprobe *tk)
70 {
71 unsigned long nhit = 0;
72 int cpu;
73
74 for_each_possible_cpu(cpu)
75 nhit += *per_cpu_ptr(tk->nhit, cpu);
76
77 return nhit;
78 }
79
80 /* Return 0 if it fails to find the symbol address */
81 static nokprobe_inline
82 unsigned long trace_kprobe_address(struct trace_kprobe *tk)
83 {
84 unsigned long addr;
85
86 if (tk->symbol) {
87 addr = (unsigned long)
88 kallsyms_lookup_name(trace_kprobe_symbol(tk));
89 if (addr)
90 addr += tk->rp.kp.offset;
91 } else {
92 addr = (unsigned long)tk->rp.kp.addr;
93 }
94 return addr;
95 }
96
97 bool trace_kprobe_on_func_entry(struct trace_event_call *call)
98 {
99 struct trace_kprobe *tk = (struct trace_kprobe *)call->data;
100
101 return kprobe_on_func_entry(tk->rp.kp.addr,
102 tk->rp.kp.addr ? NULL : tk->rp.kp.symbol_name,
103 tk->rp.kp.addr ? 0 : tk->rp.kp.offset);
104 }
105
106 bool trace_kprobe_error_injectable(struct trace_event_call *call)
107 {
108 struct trace_kprobe *tk = (struct trace_kprobe *)call->data;
109
110 return within_error_injection_list(trace_kprobe_address(tk));
111 }
112
113 static int register_kprobe_event(struct trace_kprobe *tk);
114 static int unregister_kprobe_event(struct trace_kprobe *tk);
115
116 static DEFINE_MUTEX(probe_lock);
117 static LIST_HEAD(probe_list);
118
119 static int kprobe_dispatcher(struct kprobe *kp, struct pt_regs *regs);
120 static int kretprobe_dispatcher(struct kretprobe_instance *ri,
121 struct pt_regs *regs);
122
123 /* Memory fetching by symbol */
124 struct symbol_cache {
125 char *symbol;
126 long offset;
127 unsigned long addr;
128 };
129
130 unsigned long update_symbol_cache(struct symbol_cache *sc)
131 {
132 sc->addr = (unsigned long)kallsyms_lookup_name(sc->symbol);
133
134 if (sc->addr)
135 sc->addr += sc->offset;
136
137 return sc->addr;
138 }
139
140 void free_symbol_cache(struct symbol_cache *sc)
141 {
142 kfree(sc->symbol);
143 kfree(sc);
144 }
145
146 struct symbol_cache *alloc_symbol_cache(const char *sym, long offset)
147 {
148 struct symbol_cache *sc;
149
150 if (!sym || strlen(sym) == 0)
151 return NULL;
152
153 sc = kzalloc(sizeof(struct symbol_cache), GFP_KERNEL);
154 if (!sc)
155 return NULL;
156
157 sc->symbol = kstrdup(sym, GFP_KERNEL);
158 if (!sc->symbol) {
159 kfree(sc);
160 return NULL;
161 }
162 sc->offset = offset;
163 update_symbol_cache(sc);
164
165 return sc;
166 }
167
168 /*
169 * Kprobes-specific fetch functions
170 */
171 #define DEFINE_FETCH_stack(type) \
172 static void FETCH_FUNC_NAME(stack, type)(struct pt_regs *regs, \
173 void *offset, void *dest) \
174 { \
175 *(type *)dest = (type)regs_get_kernel_stack_nth(regs, \
176 (unsigned int)((unsigned long)offset)); \
177 } \
178 NOKPROBE_SYMBOL(FETCH_FUNC_NAME(stack, type));
179
180 DEFINE_BASIC_FETCH_FUNCS(stack)
181 /* No string on the stack entry */
182 #define fetch_stack_string NULL
183 #define fetch_stack_string_size NULL
184
185 #define DEFINE_FETCH_memory(type) \
186 static void FETCH_FUNC_NAME(memory, type)(struct pt_regs *regs, \
187 void *addr, void *dest) \
188 { \
189 type retval; \
190 if (probe_kernel_address(addr, retval)) \
191 *(type *)dest = 0; \
192 else \
193 *(type *)dest = retval; \
194 } \
195 NOKPROBE_SYMBOL(FETCH_FUNC_NAME(memory, type));
196
197 DEFINE_BASIC_FETCH_FUNCS(memory)
198 /*
199 * Fetch a null-terminated string. Caller MUST set *(u32 *)dest with max
200 * length and relative data location.
201 */
202 static void FETCH_FUNC_NAME(memory, string)(struct pt_regs *regs,
203 void *addr, void *dest)
204 {
205 int maxlen = get_rloc_len(*(u32 *)dest);
206 u8 *dst = get_rloc_data(dest);
207 long ret;
208
209 if (!maxlen)
210 return;
211
212 /*
213 * Try to get string again, since the string can be changed while
214 * probing.
215 */
216 ret = strncpy_from_unsafe(dst, addr, maxlen);
217
218 if (ret < 0) { /* Failed to fetch string */
219 dst[0] = '\0';
220 *(u32 *)dest = make_data_rloc(0, get_rloc_offs(*(u32 *)dest));
221 } else {
222 *(u32 *)dest = make_data_rloc(ret, get_rloc_offs(*(u32 *)dest));
223 }
224 }
225 NOKPROBE_SYMBOL(FETCH_FUNC_NAME(memory, string));
226
227 /* Return the length of string -- including null terminal byte */
228 static void FETCH_FUNC_NAME(memory, string_size)(struct pt_regs *regs,
229 void *addr, void *dest)
230 {
231 mm_segment_t old_fs;
232 int ret, len = 0;
233 u8 c;
234
235 old_fs = get_fs();
236 set_fs(KERNEL_DS);
237 pagefault_disable();
238
239 do {
240 ret = __copy_from_user_inatomic(&c, (u8 *)addr + len, 1);
241 len++;
242 } while (c && ret == 0 && len < MAX_STRING_SIZE);
243
244 pagefault_enable();
245 set_fs(old_fs);
246
247 if (ret < 0) /* Failed to check the length */
248 *(u32 *)dest = 0;
249 else
250 *(u32 *)dest = len;
251 }
252 NOKPROBE_SYMBOL(FETCH_FUNC_NAME(memory, string_size));
253
254 #define DEFINE_FETCH_symbol(type) \
255 void FETCH_FUNC_NAME(symbol, type)(struct pt_regs *regs, void *data, void *dest)\
256 { \
257 struct symbol_cache *sc = data; \
258 if (sc->addr) \
259 fetch_memory_##type(regs, (void *)sc->addr, dest); \
260 else \
261 *(type *)dest = 0; \
262 } \
263 NOKPROBE_SYMBOL(FETCH_FUNC_NAME(symbol, type));
264
265 DEFINE_BASIC_FETCH_FUNCS(symbol)
266 DEFINE_FETCH_symbol(string)
267 DEFINE_FETCH_symbol(string_size)
268
269 /* kprobes don't support file_offset fetch methods */
270 #define fetch_file_offset_u8 NULL
271 #define fetch_file_offset_u16 NULL
272 #define fetch_file_offset_u32 NULL
273 #define fetch_file_offset_u64 NULL
274 #define fetch_file_offset_string NULL
275 #define fetch_file_offset_string_size NULL
276
277 /* Fetch type information table */
278 static const struct fetch_type kprobes_fetch_type_table[] = {
279 /* Special types */
280 [FETCH_TYPE_STRING] = __ASSIGN_FETCH_TYPE("string", string, string,
281 sizeof(u32), 1, "__data_loc char[]"),
282 [FETCH_TYPE_STRSIZE] = __ASSIGN_FETCH_TYPE("string_size", u32,
283 string_size, sizeof(u32), 0, "u32"),
284 /* Basic types */
285 ASSIGN_FETCH_TYPE(u8, u8, 0),
286 ASSIGN_FETCH_TYPE(u16, u16, 0),
287 ASSIGN_FETCH_TYPE(u32, u32, 0),
288 ASSIGN_FETCH_TYPE(u64, u64, 0),
289 ASSIGN_FETCH_TYPE(s8, u8, 1),
290 ASSIGN_FETCH_TYPE(s16, u16, 1),
291 ASSIGN_FETCH_TYPE(s32, u32, 1),
292 ASSIGN_FETCH_TYPE(s64, u64, 1),
293 ASSIGN_FETCH_TYPE_ALIAS(x8, u8, u8, 0),
294 ASSIGN_FETCH_TYPE_ALIAS(x16, u16, u16, 0),
295 ASSIGN_FETCH_TYPE_ALIAS(x32, u32, u32, 0),
296 ASSIGN_FETCH_TYPE_ALIAS(x64, u64, u64, 0),
297
298 ASSIGN_FETCH_TYPE_END
299 };
300
301 /*
302 * Allocate new trace_probe and initialize it (including kprobes).
303 */
304 static struct trace_kprobe *alloc_trace_kprobe(const char *group,
305 const char *event,
306 void *addr,
307 const char *symbol,
308 unsigned long offs,
309 int maxactive,
310 int nargs, bool is_return)
311 {
312 struct trace_kprobe *tk;
313 int ret = -ENOMEM;
314
315 tk = kzalloc(SIZEOF_TRACE_KPROBE(nargs), GFP_KERNEL);
316 if (!tk)
317 return ERR_PTR(ret);
318
319 tk->nhit = alloc_percpu(unsigned long);
320 if (!tk->nhit)
321 goto error;
322
323 if (symbol) {
324 tk->symbol = kstrdup(symbol, GFP_KERNEL);
325 if (!tk->symbol)
326 goto error;
327 tk->rp.kp.symbol_name = tk->symbol;
328 tk->rp.kp.offset = offs;
329 } else
330 tk->rp.kp.addr = addr;
331
332 if (is_return)
333 tk->rp.handler = kretprobe_dispatcher;
334 else
335 tk->rp.kp.pre_handler = kprobe_dispatcher;
336
337 tk->rp.maxactive = maxactive;
338
339 if (!event || !is_good_name(event)) {
340 ret = -EINVAL;
341 goto error;
342 }
343
344 tk->tp.call.class = &tk->tp.class;
345 tk->tp.call.name = kstrdup(event, GFP_KERNEL);
346 if (!tk->tp.call.name)
347 goto error;
348
349 if (!group || !is_good_name(group)) {
350 ret = -EINVAL;
351 goto error;
352 }
353
354 tk->tp.class.system = kstrdup(group, GFP_KERNEL);
355 if (!tk->tp.class.system)
356 goto error;
357
358 INIT_LIST_HEAD(&tk->list);
359 INIT_LIST_HEAD(&tk->tp.files);
360 return tk;
361 error:
362 kfree(tk->tp.call.name);
363 kfree(tk->symbol);
364 free_percpu(tk->nhit);
365 kfree(tk);
366 return ERR_PTR(ret);
367 }
368
369 static void free_trace_kprobe(struct trace_kprobe *tk)
370 {
371 int i;
372
373 for (i = 0; i < tk->tp.nr_args; i++)
374 traceprobe_free_probe_arg(&tk->tp.args[i]);
375
376 kfree(tk->tp.call.class->system);
377 kfree(tk->tp.call.name);
378 kfree(tk->symbol);
379 free_percpu(tk->nhit);
380 kfree(tk);
381 }
382
383 static struct trace_kprobe *find_trace_kprobe(const char *event,
384 const char *group)
385 {
386 struct trace_kprobe *tk;
387
388 list_for_each_entry(tk, &probe_list, list)
389 if (strcmp(trace_event_name(&tk->tp.call), event) == 0 &&
390 strcmp(tk->tp.call.class->system, group) == 0)
391 return tk;
392 return NULL;
393 }
394
395 static inline int __enable_trace_kprobe(struct trace_kprobe *tk)
396 {
397 int ret = 0;
398
399 if (trace_probe_is_registered(&tk->tp) && !trace_kprobe_has_gone(tk)) {
400 if (trace_kprobe_is_return(tk))
401 ret = enable_kretprobe(&tk->rp);
402 else
403 ret = enable_kprobe(&tk->rp.kp);
404 }
405
406 return ret;
407 }
408
409 /*
410 * Enable trace_probe
411 * if the file is NULL, enable "perf" handler, or enable "trace" handler.
412 */
413 static int
414 enable_trace_kprobe(struct trace_kprobe *tk, struct trace_event_file *file)
415 {
416 struct event_file_link *link;
417 int ret = 0;
418
419 if (file) {
420 link = kmalloc(sizeof(*link), GFP_KERNEL);
421 if (!link) {
422 ret = -ENOMEM;
423 goto out;
424 }
425
426 link->file = file;
427 list_add_tail_rcu(&link->list, &tk->tp.files);
428
429 tk->tp.flags |= TP_FLAG_TRACE;
430 ret = __enable_trace_kprobe(tk);
431 if (ret) {
432 list_del_rcu(&link->list);
433 kfree(link);
434 tk->tp.flags &= ~TP_FLAG_TRACE;
435 }
436
437 } else {
438 tk->tp.flags |= TP_FLAG_PROFILE;
439 ret = __enable_trace_kprobe(tk);
440 if (ret)
441 tk->tp.flags &= ~TP_FLAG_PROFILE;
442 }
443 out:
444 return ret;
445 }
446
447 /*
448 * Disable trace_probe
449 * if the file is NULL, disable "perf" handler, or disable "trace" handler.
450 */
451 static int
452 disable_trace_kprobe(struct trace_kprobe *tk, struct trace_event_file *file)
453 {
454 struct event_file_link *link = NULL;
455 int wait = 0;
456 int ret = 0;
457
458 if (file) {
459 link = find_event_file_link(&tk->tp, file);
460 if (!link) {
461 ret = -EINVAL;
462 goto out;
463 }
464
465 list_del_rcu(&link->list);
466 wait = 1;
467 if (!list_empty(&tk->tp.files))
468 goto out;
469
470 tk->tp.flags &= ~TP_FLAG_TRACE;
471 } else
472 tk->tp.flags &= ~TP_FLAG_PROFILE;
473
474 if (!trace_probe_is_enabled(&tk->tp) && trace_probe_is_registered(&tk->tp)) {
475 if (trace_kprobe_is_return(tk))
476 disable_kretprobe(&tk->rp);
477 else
478 disable_kprobe(&tk->rp.kp);
479 wait = 1;
480 }
481
482 /*
483 * if tk is not added to any list, it must be a local trace_kprobe
484 * created with perf_event_open. We don't need to wait for these
485 * trace_kprobes
486 */
487 if (list_empty(&tk->list))
488 wait = 0;
489 out:
490 if (wait) {
491 /*
492 * Synchronize with kprobe_trace_func/kretprobe_trace_func
493 * to ensure disabled (all running handlers are finished).
494 * This is not only for kfree(), but also the caller,
495 * trace_remove_event_call() supposes it for releasing
496 * event_call related objects, which will be accessed in
497 * the kprobe_trace_func/kretprobe_trace_func.
498 */
499 synchronize_sched();
500 kfree(link); /* Ignored if link == NULL */
501 }
502
503 return ret;
504 }
505
506 #if defined(CONFIG_KPROBES_ON_FTRACE) && \
507 !defined(CONFIG_KPROBE_EVENTS_ON_NOTRACE)
508 static bool within_notrace_func(struct trace_kprobe *tk)
509 {
510 unsigned long offset, size, addr;
511
512 addr = trace_kprobe_address(tk);
513 if (!addr || !kallsyms_lookup_size_offset(addr, &size, &offset))
514 return false;
515
516 /* Get the entry address of the target function */
517 addr -= offset;
518
519 /*
520 * Since ftrace_location_range() does inclusive range check, we need
521 * to subtract 1 byte from the end address.
522 */
523 return !ftrace_location_range(addr, addr + size - 1);
524 }
525 #else
526 #define within_notrace_func(tk) (false)
527 #endif
528
529 /* Internal register function - just handle k*probes and flags */
530 static int __register_trace_kprobe(struct trace_kprobe *tk)
531 {
532 int i, ret;
533
534 if (trace_probe_is_registered(&tk->tp))
535 return -EINVAL;
536
537 if (within_notrace_func(tk)) {
538 pr_warn("Could not probe notrace function %s\n",
539 trace_kprobe_symbol(tk));
540 return -EINVAL;
541 }
542
543 for (i = 0; i < tk->tp.nr_args; i++)
544 traceprobe_update_arg(&tk->tp.args[i]);
545
546 /* Set/clear disabled flag according to tp->flag */
547 if (trace_probe_is_enabled(&tk->tp))
548 tk->rp.kp.flags &= ~KPROBE_FLAG_DISABLED;
549 else
550 tk->rp.kp.flags |= KPROBE_FLAG_DISABLED;
551
552 if (trace_kprobe_is_return(tk))
553 ret = register_kretprobe(&tk->rp);
554 else
555 ret = register_kprobe(&tk->rp.kp);
556
557 if (ret == 0)
558 tk->tp.flags |= TP_FLAG_REGISTERED;
559 else {
560 if (ret == -ENOENT && trace_kprobe_is_on_module(tk)) {
561 pr_warn("This probe might be able to register after target module is loaded. Continue.\n");
562 ret = 0;
563 } else if (ret == -EILSEQ) {
564 pr_warn("Probing address(0x%p) is not an instruction boundary.\n",
565 tk->rp.kp.addr);
566 ret = -EINVAL;
567 }
568 }
569
570 return ret;
571 }
572
573 /* Internal unregister function - just handle k*probes and flags */
574 static void __unregister_trace_kprobe(struct trace_kprobe *tk)
575 {
576 if (trace_probe_is_registered(&tk->tp)) {
577 if (trace_kprobe_is_return(tk))
578 unregister_kretprobe(&tk->rp);
579 else
580 unregister_kprobe(&tk->rp.kp);
581 tk->tp.flags &= ~TP_FLAG_REGISTERED;
582 /* Cleanup kprobe for reuse */
583 if (tk->rp.kp.symbol_name)
584 tk->rp.kp.addr = NULL;
585 }
586 }
587
588 /* Unregister a trace_probe and probe_event: call with locking probe_lock */
589 static int unregister_trace_kprobe(struct trace_kprobe *tk)
590 {
591 /* Enabled event can not be unregistered */
592 if (trace_probe_is_enabled(&tk->tp))
593 return -EBUSY;
594
595 /* Will fail if probe is being used by ftrace or perf */
596 if (unregister_kprobe_event(tk))
597 return -EBUSY;
598
599 __unregister_trace_kprobe(tk);
600 list_del(&tk->list);
601
602 return 0;
603 }
604
605 /* Register a trace_probe and probe_event */
606 static int register_trace_kprobe(struct trace_kprobe *tk)
607 {
608 struct trace_kprobe *old_tk;
609 int ret;
610
611 mutex_lock(&probe_lock);
612
613 /* Delete old (same name) event if exist */
614 old_tk = find_trace_kprobe(trace_event_name(&tk->tp.call),
615 tk->tp.call.class->system);
616 if (old_tk) {
617 ret = unregister_trace_kprobe(old_tk);
618 if (ret < 0)
619 goto end;
620 free_trace_kprobe(old_tk);
621 }
622
623 /* Register new event */
624 ret = register_kprobe_event(tk);
625 if (ret) {
626 pr_warn("Failed to register probe event(%d)\n", ret);
627 goto end;
628 }
629
630 /* Register k*probe */
631 ret = __register_trace_kprobe(tk);
632 if (ret < 0)
633 unregister_kprobe_event(tk);
634 else
635 list_add_tail(&tk->list, &probe_list);
636
637 end:
638 mutex_unlock(&probe_lock);
639 return ret;
640 }
641
642 /* Module notifier call back, checking event on the module */
643 static int trace_kprobe_module_callback(struct notifier_block *nb,
644 unsigned long val, void *data)
645 {
646 struct module *mod = data;
647 struct trace_kprobe *tk;
648 int ret;
649
650 if (val != MODULE_STATE_COMING)
651 return NOTIFY_DONE;
652
653 /* Update probes on coming module */
654 mutex_lock(&probe_lock);
655 list_for_each_entry(tk, &probe_list, list) {
656 if (trace_kprobe_within_module(tk, mod)) {
657 /* Don't need to check busy - this should have gone. */
658 __unregister_trace_kprobe(tk);
659 ret = __register_trace_kprobe(tk);
660 if (ret)
661 pr_warn("Failed to re-register probe %s on %s: %d\n",
662 trace_event_name(&tk->tp.call),
663 mod->name, ret);
664 }
665 }
666 mutex_unlock(&probe_lock);
667
668 return NOTIFY_DONE;
669 }
670
671 static struct notifier_block trace_kprobe_module_nb = {
672 .notifier_call = trace_kprobe_module_callback,
673 .priority = 1 /* Invoked after kprobe module callback */
674 };
675
676 /* Convert certain expected symbols into '_' when generating event names */
677 static inline void sanitize_event_name(char *name)
678 {
679 while (*name++ != '\0')
680 if (*name == ':' || *name == '.')
681 *name = '_';
682 }
683
684 static int create_trace_kprobe(int argc, char **argv)
685 {
686 /*
687 * Argument syntax:
688 * - Add kprobe:
689 * p[:[GRP/]EVENT] [MOD:]KSYM[+OFFS]|KADDR [FETCHARGS]
690 * - Add kretprobe:
691 * r[MAXACTIVE][:[GRP/]EVENT] [MOD:]KSYM[+0] [FETCHARGS]
692 * Fetch args:
693 * $retval : fetch return value
694 * $stack : fetch stack address
695 * $stackN : fetch Nth of stack (N:0-)
696 * $comm : fetch current task comm
697 * @ADDR : fetch memory at ADDR (ADDR should be in kernel)
698 * @SYM[+|-offs] : fetch memory at SYM +|- offs (SYM is a data symbol)
699 * %REG : fetch register REG
700 * Dereferencing memory fetch:
701 * +|-offs(ARG) : fetch memory at ARG +|- offs address.
702 * Alias name of args:
703 * NAME=FETCHARG : set NAME as alias of FETCHARG.
704 * Type of args:
705 * FETCHARG:TYPE : use TYPE instead of unsigned long.
706 */
707 struct trace_kprobe *tk;
708 int i, ret = 0;
709 bool is_return = false, is_delete = false;
710 char *symbol = NULL, *event = NULL, *group = NULL;
711 int maxactive = 0;
712 char *arg;
713 long offset = 0;
714 void *addr = NULL;
715 char buf[MAX_EVENT_NAME_LEN];
716
717 /* argc must be >= 1 */
718 if (argv[0][0] == 'p')
719 is_return = false;
720 else if (argv[0][0] == 'r')
721 is_return = true;
722 else if (argv[0][0] == '-')
723 is_delete = true;
724 else {
725 pr_info("Probe definition must be started with 'p', 'r' or"
726 " '-'.\n");
727 return -EINVAL;
728 }
729
730 event = strchr(&argv[0][1], ':');
731 if (event) {
732 event[0] = '\0';
733 event++;
734 }
735 if (is_return && isdigit(argv[0][1])) {
736 ret = kstrtouint(&argv[0][1], 0, &maxactive);
737 if (ret) {
738 pr_info("Failed to parse maxactive.\n");
739 return ret;
740 }
741 /* kretprobes instances are iterated over via a list. The
742 * maximum should stay reasonable.
743 */
744 if (maxactive > KRETPROBE_MAXACTIVE_MAX) {
745 pr_info("Maxactive is too big (%d > %d).\n",
746 maxactive, KRETPROBE_MAXACTIVE_MAX);
747 return -E2BIG;
748 }
749 }
750
751 if (event) {
752 if (strchr(event, '/')) {
753 group = event;
754 event = strchr(group, '/') + 1;
755 event[-1] = '\0';
756 if (strlen(group) == 0) {
757 pr_info("Group name is not specified\n");
758 return -EINVAL;
759 }
760 }
761 if (strlen(event) == 0) {
762 pr_info("Event name is not specified\n");
763 return -EINVAL;
764 }
765 }
766 if (!group)
767 group = KPROBE_EVENT_SYSTEM;
768
769 if (is_delete) {
770 if (!event) {
771 pr_info("Delete command needs an event name.\n");
772 return -EINVAL;
773 }
774 mutex_lock(&probe_lock);
775 tk = find_trace_kprobe(event, group);
776 if (!tk) {
777 mutex_unlock(&probe_lock);
778 pr_info("Event %s/%s doesn't exist.\n", group, event);
779 return -ENOENT;
780 }
781 /* delete an event */
782 ret = unregister_trace_kprobe(tk);
783 if (ret == 0)
784 free_trace_kprobe(tk);
785 mutex_unlock(&probe_lock);
786 return ret;
787 }
788
789 if (argc < 2) {
790 pr_info("Probe point is not specified.\n");
791 return -EINVAL;
792 }
793
794 /* try to parse an address. if that fails, try to read the
795 * input as a symbol. */
796 if (kstrtoul(argv[1], 0, (unsigned long *)&addr)) {
797 /* a symbol specified */
798 symbol = argv[1];
799 /* TODO: support .init module functions */
800 ret = traceprobe_split_symbol_offset(symbol, &offset);
801 if (ret || offset < 0 || offset > UINT_MAX) {
802 pr_info("Failed to parse either an address or a symbol.\n");
803 return ret;
804 }
805 if (offset && is_return &&
806 !kprobe_on_func_entry(NULL, symbol, offset)) {
807 pr_info("Given offset is not valid for return probe.\n");
808 return -EINVAL;
809 }
810 }
811 argc -= 2; argv += 2;
812
813 /* setup a probe */
814 if (!event) {
815 /* Make a new event name */
816 if (symbol)
817 snprintf(buf, MAX_EVENT_NAME_LEN, "%c_%s_%ld",
818 is_return ? 'r' : 'p', symbol, offset);
819 else
820 snprintf(buf, MAX_EVENT_NAME_LEN, "%c_0x%p",
821 is_return ? 'r' : 'p', addr);
822 sanitize_event_name(buf);
823 event = buf;
824 }
825 tk = alloc_trace_kprobe(group, event, addr, symbol, offset, maxactive,
826 argc, is_return);
827 if (IS_ERR(tk)) {
828 pr_info("Failed to allocate trace_probe.(%d)\n",
829 (int)PTR_ERR(tk));
830 return PTR_ERR(tk);
831 }
832
833 /* parse arguments */
834 ret = 0;
835 for (i = 0; i < argc && i < MAX_TRACE_ARGS; i++) {
836 struct probe_arg *parg = &tk->tp.args[i];
837
838 /* Increment count for freeing args in error case */
839 tk->tp.nr_args++;
840
841 /* Parse argument name */
842 arg = strchr(argv[i], '=');
843 if (arg) {
844 *arg++ = '\0';
845 parg->name = kstrdup(argv[i], GFP_KERNEL);
846 } else {
847 arg = argv[i];
848 /* If argument name is omitted, set "argN" */
849 snprintf(buf, MAX_EVENT_NAME_LEN, "arg%d", i + 1);
850 parg->name = kstrdup(buf, GFP_KERNEL);
851 }
852
853 if (!parg->name) {
854 pr_info("Failed to allocate argument[%d] name.\n", i);
855 ret = -ENOMEM;
856 goto error;
857 }
858
859 if (!is_good_name(parg->name)) {
860 pr_info("Invalid argument[%d] name: %s\n",
861 i, parg->name);
862 ret = -EINVAL;
863 goto error;
864 }
865
866 if (traceprobe_conflict_field_name(parg->name,
867 tk->tp.args, i)) {
868 pr_info("Argument[%d] name '%s' conflicts with "
869 "another field.\n", i, argv[i]);
870 ret = -EINVAL;
871 goto error;
872 }
873
874 /* Parse fetch argument */
875 ret = traceprobe_parse_probe_arg(arg, &tk->tp.size, parg,
876 is_return, true,
877 kprobes_fetch_type_table);
878 if (ret) {
879 pr_info("Parse error at argument[%d]. (%d)\n", i, ret);
880 goto error;
881 }
882 }
883
884 ret = register_trace_kprobe(tk);
885 if (ret)
886 goto error;
887 return 0;
888
889 error:
890 free_trace_kprobe(tk);
891 return ret;
892 }
893
894 static int release_all_trace_kprobes(void)
895 {
896 struct trace_kprobe *tk;
897 int ret = 0;
898
899 mutex_lock(&probe_lock);
900 /* Ensure no probe is in use. */
901 list_for_each_entry(tk, &probe_list, list)
902 if (trace_probe_is_enabled(&tk->tp)) {
903 ret = -EBUSY;
904 goto end;
905 }
906 /* TODO: Use batch unregistration */
907 while (!list_empty(&probe_list)) {
908 tk = list_entry(probe_list.next, struct trace_kprobe, list);
909 ret = unregister_trace_kprobe(tk);
910 if (ret)
911 goto end;
912 free_trace_kprobe(tk);
913 }
914
915 end:
916 mutex_unlock(&probe_lock);
917
918 return ret;
919 }
920
921 /* Probes listing interfaces */
922 static void *probes_seq_start(struct seq_file *m, loff_t *pos)
923 {
924 mutex_lock(&probe_lock);
925 return seq_list_start(&probe_list, *pos);
926 }
927
928 static void *probes_seq_next(struct seq_file *m, void *v, loff_t *pos)
929 {
930 return seq_list_next(v, &probe_list, pos);
931 }
932
933 static void probes_seq_stop(struct seq_file *m, void *v)
934 {
935 mutex_unlock(&probe_lock);
936 }
937
938 static int probes_seq_show(struct seq_file *m, void *v)
939 {
940 struct trace_kprobe *tk = v;
941 int i;
942
943 seq_putc(m, trace_kprobe_is_return(tk) ? 'r' : 'p');
944 seq_printf(m, ":%s/%s", tk->tp.call.class->system,
945 trace_event_name(&tk->tp.call));
946
947 if (!tk->symbol)
948 seq_printf(m, " 0x%p", tk->rp.kp.addr);
949 else if (tk->rp.kp.offset)
950 seq_printf(m, " %s+%u", trace_kprobe_symbol(tk),
951 tk->rp.kp.offset);
952 else
953 seq_printf(m, " %s", trace_kprobe_symbol(tk));
954
955 for (i = 0; i < tk->tp.nr_args; i++)
956 seq_printf(m, " %s=%s", tk->tp.args[i].name, tk->tp.args[i].comm);
957 seq_putc(m, '\n');
958
959 return 0;
960 }
961
962 static const struct seq_operations probes_seq_op = {
963 .start = probes_seq_start,
964 .next = probes_seq_next,
965 .stop = probes_seq_stop,
966 .show = probes_seq_show
967 };
968
969 static int probes_open(struct inode *inode, struct file *file)
970 {
971 int ret;
972
973 if ((file->f_mode & FMODE_WRITE) && (file->f_flags & O_TRUNC)) {
974 ret = release_all_trace_kprobes();
975 if (ret < 0)
976 return ret;
977 }
978
979 return seq_open(file, &probes_seq_op);
980 }
981
982 static ssize_t probes_write(struct file *file, const char __user *buffer,
983 size_t count, loff_t *ppos)
984 {
985 return trace_parse_run_command(file, buffer, count, ppos,
986 create_trace_kprobe);
987 }
988
989 static const struct file_operations kprobe_events_ops = {
990 .owner = THIS_MODULE,
991 .open = probes_open,
992 .read = seq_read,
993 .llseek = seq_lseek,
994 .release = seq_release,
995 .write = probes_write,
996 };
997
998 /* Probes profiling interfaces */
999 static int probes_profile_seq_show(struct seq_file *m, void *v)
1000 {
1001 struct trace_kprobe *tk = v;
1002
1003 seq_printf(m, " %-44s %15lu %15lu\n",
1004 trace_event_name(&tk->tp.call),
1005 trace_kprobe_nhit(tk),
1006 tk->rp.kp.nmissed);
1007
1008 return 0;
1009 }
1010
1011 static const struct seq_operations profile_seq_op = {
1012 .start = probes_seq_start,
1013 .next = probes_seq_next,
1014 .stop = probes_seq_stop,
1015 .show = probes_profile_seq_show
1016 };
1017
1018 static int profile_open(struct inode *inode, struct file *file)
1019 {
1020 return seq_open(file, &profile_seq_op);
1021 }
1022
1023 static const struct file_operations kprobe_profile_ops = {
1024 .owner = THIS_MODULE,
1025 .open = profile_open,
1026 .read = seq_read,
1027 .llseek = seq_lseek,
1028 .release = seq_release,
1029 };
1030
1031 /* Kprobe handler */
1032 static nokprobe_inline void
1033 __kprobe_trace_func(struct trace_kprobe *tk, struct pt_regs *regs,
1034 struct trace_event_file *trace_file)
1035 {
1036 struct kprobe_trace_entry_head *entry;
1037 struct ring_buffer_event *event;
1038 struct ring_buffer *buffer;
1039 int size, dsize, pc;
1040 unsigned long irq_flags;
1041 struct trace_event_call *call = &tk->tp.call;
1042
1043 WARN_ON(call != trace_file->event_call);
1044
1045 if (trace_trigger_soft_disabled(trace_file))
1046 return;
1047
1048 local_save_flags(irq_flags);
1049 pc = preempt_count();
1050
1051 dsize = __get_data_size(&tk->tp, regs);
1052 size = sizeof(*entry) + tk->tp.size + dsize;
1053
1054 event = trace_event_buffer_lock_reserve(&buffer, trace_file,
1055 call->event.type,
1056 size, irq_flags, pc);
1057 if (!event)
1058 return;
1059
1060 entry = ring_buffer_event_data(event);
1061 entry->ip = (unsigned long)tk->rp.kp.addr;
1062 store_trace_args(sizeof(*entry), &tk->tp, regs, (u8 *)&entry[1], dsize);
1063
1064 event_trigger_unlock_commit_regs(trace_file, buffer, event,
1065 entry, irq_flags, pc, regs);
1066 }
1067
1068 static void
1069 kprobe_trace_func(struct trace_kprobe *tk, struct pt_regs *regs)
1070 {
1071 struct event_file_link *link;
1072
1073 list_for_each_entry_rcu(link, &tk->tp.files, list)
1074 __kprobe_trace_func(tk, regs, link->file);
1075 }
1076 NOKPROBE_SYMBOL(kprobe_trace_func);
1077
1078 /* Kretprobe handler */
1079 static nokprobe_inline void
1080 __kretprobe_trace_func(struct trace_kprobe *tk, struct kretprobe_instance *ri,
1081 struct pt_regs *regs,
1082 struct trace_event_file *trace_file)
1083 {
1084 struct kretprobe_trace_entry_head *entry;
1085 struct ring_buffer_event *event;
1086 struct ring_buffer *buffer;
1087 int size, pc, dsize;
1088 unsigned long irq_flags;
1089 struct trace_event_call *call = &tk->tp.call;
1090
1091 WARN_ON(call != trace_file->event_call);
1092
1093 if (trace_trigger_soft_disabled(trace_file))
1094 return;
1095
1096 local_save_flags(irq_flags);
1097 pc = preempt_count();
1098
1099 dsize = __get_data_size(&tk->tp, regs);
1100 size = sizeof(*entry) + tk->tp.size + dsize;
1101
1102 event = trace_event_buffer_lock_reserve(&buffer, trace_file,
1103 call->event.type,
1104 size, irq_flags, pc);
1105 if (!event)
1106 return;
1107
1108 entry = ring_buffer_event_data(event);
1109 entry->func = (unsigned long)tk->rp.kp.addr;
1110 entry->ret_ip = (unsigned long)ri->ret_addr;
1111 store_trace_args(sizeof(*entry), &tk->tp, regs, (u8 *)&entry[1], dsize);
1112
1113 event_trigger_unlock_commit_regs(trace_file, buffer, event,
1114 entry, irq_flags, pc, regs);
1115 }
1116
1117 static void
1118 kretprobe_trace_func(struct trace_kprobe *tk, struct kretprobe_instance *ri,
1119 struct pt_regs *regs)
1120 {
1121 struct event_file_link *link;
1122
1123 list_for_each_entry_rcu(link, &tk->tp.files, list)
1124 __kretprobe_trace_func(tk, ri, regs, link->file);
1125 }
1126 NOKPROBE_SYMBOL(kretprobe_trace_func);
1127
1128 /* Event entry printers */
1129 static enum print_line_t
1130 print_kprobe_event(struct trace_iterator *iter, int flags,
1131 struct trace_event *event)
1132 {
1133 struct kprobe_trace_entry_head *field;
1134 struct trace_seq *s = &iter->seq;
1135 struct trace_probe *tp;
1136 u8 *data;
1137 int i;
1138
1139 field = (struct kprobe_trace_entry_head *)iter->ent;
1140 tp = container_of(event, struct trace_probe, call.event);
1141
1142 trace_seq_printf(s, "%s: (", trace_event_name(&tp->call));
1143
1144 if (!seq_print_ip_sym(s, field->ip, flags | TRACE_ITER_SYM_OFFSET))
1145 goto out;
1146
1147 trace_seq_putc(s, ')');
1148
1149 data = (u8 *)&field[1];
1150 for (i = 0; i < tp->nr_args; i++)
1151 if (!tp->args[i].type->print(s, tp->args[i].name,
1152 data + tp->args[i].offset, field))
1153 goto out;
1154
1155 trace_seq_putc(s, '\n');
1156 out:
1157 return trace_handle_return(s);
1158 }
1159
1160 static enum print_line_t
1161 print_kretprobe_event(struct trace_iterator *iter, int flags,
1162 struct trace_event *event)
1163 {
1164 struct kretprobe_trace_entry_head *field;
1165 struct trace_seq *s = &iter->seq;
1166 struct trace_probe *tp;
1167 u8 *data;
1168 int i;
1169
1170 field = (struct kretprobe_trace_entry_head *)iter->ent;
1171 tp = container_of(event, struct trace_probe, call.event);
1172
1173 trace_seq_printf(s, "%s: (", trace_event_name(&tp->call));
1174
1175 if (!seq_print_ip_sym(s, field->ret_ip, flags | TRACE_ITER_SYM_OFFSET))
1176 goto out;
1177
1178 trace_seq_puts(s, " <- ");
1179
1180 if (!seq_print_ip_sym(s, field->func, flags & ~TRACE_ITER_SYM_OFFSET))
1181 goto out;
1182
1183 trace_seq_putc(s, ')');
1184
1185 data = (u8 *)&field[1];
1186 for (i = 0; i < tp->nr_args; i++)
1187 if (!tp->args[i].type->print(s, tp->args[i].name,
1188 data + tp->args[i].offset, field))
1189 goto out;
1190
1191 trace_seq_putc(s, '\n');
1192
1193 out:
1194 return trace_handle_return(s);
1195 }
1196
1197
1198 static int kprobe_event_define_fields(struct trace_event_call *event_call)
1199 {
1200 int ret, i;
1201 struct kprobe_trace_entry_head field;
1202 struct trace_kprobe *tk = (struct trace_kprobe *)event_call->data;
1203
1204 DEFINE_FIELD(unsigned long, ip, FIELD_STRING_IP, 0);
1205 /* Set argument names as fields */
1206 for (i = 0; i < tk->tp.nr_args; i++) {
1207 struct probe_arg *parg = &tk->tp.args[i];
1208
1209 ret = trace_define_field(event_call, parg->type->fmttype,
1210 parg->name,
1211 sizeof(field) + parg->offset,
1212 parg->type->size,
1213 parg->type->is_signed,
1214 FILTER_OTHER);
1215 if (ret)
1216 return ret;
1217 }
1218 return 0;
1219 }
1220
1221 static int kretprobe_event_define_fields(struct trace_event_call *event_call)
1222 {
1223 int ret, i;
1224 struct kretprobe_trace_entry_head field;
1225 struct trace_kprobe *tk = (struct trace_kprobe *)event_call->data;
1226
1227 DEFINE_FIELD(unsigned long, func, FIELD_STRING_FUNC, 0);
1228 DEFINE_FIELD(unsigned long, ret_ip, FIELD_STRING_RETIP, 0);
1229 /* Set argument names as fields */
1230 for (i = 0; i < tk->tp.nr_args; i++) {
1231 struct probe_arg *parg = &tk->tp.args[i];
1232
1233 ret = trace_define_field(event_call, parg->type->fmttype,
1234 parg->name,
1235 sizeof(field) + parg->offset,
1236 parg->type->size,
1237 parg->type->is_signed,
1238 FILTER_OTHER);
1239 if (ret)
1240 return ret;
1241 }
1242 return 0;
1243 }
1244
1245 #ifdef CONFIG_PERF_EVENTS
1246
1247 /* Kprobe profile handler */
1248 static int
1249 kprobe_perf_func(struct trace_kprobe *tk, struct pt_regs *regs)
1250 {
1251 struct trace_event_call *call = &tk->tp.call;
1252 struct kprobe_trace_entry_head *entry;
1253 struct hlist_head *head;
1254 int size, __size, dsize;
1255 int rctx;
1256
1257 if (bpf_prog_array_valid(call)) {
1258 unsigned long orig_ip = instruction_pointer(regs);
1259 int ret;
1260
1261 ret = trace_call_bpf(call, regs);
1262
1263 /*
1264 * We need to check and see if we modified the pc of the
1265 * pt_regs, and if so return 1 so that we don't do the
1266 * single stepping.
1267 */
1268 if (orig_ip != instruction_pointer(regs))
1269 return 1;
1270 if (!ret)
1271 return 0;
1272 }
1273
1274 head = this_cpu_ptr(call->perf_events);
1275 if (hlist_empty(head))
1276 return 0;
1277
1278 dsize = __get_data_size(&tk->tp, regs);
1279 __size = sizeof(*entry) + tk->tp.size + dsize;
1280 size = ALIGN(__size + sizeof(u32), sizeof(u64));
1281 size -= sizeof(u32);
1282
1283 entry = perf_trace_buf_alloc(size, NULL, &rctx);
1284 if (!entry)
1285 return 0;
1286
1287 entry->ip = (unsigned long)tk->rp.kp.addr;
1288 memset(&entry[1], 0, dsize);
1289 store_trace_args(sizeof(*entry), &tk->tp, regs, (u8 *)&entry[1], dsize);
1290 perf_trace_buf_submit(entry, size, rctx, call->event.type, 1, regs,
1291 head, NULL);
1292 return 0;
1293 }
1294 NOKPROBE_SYMBOL(kprobe_perf_func);
1295
1296 /* Kretprobe profile handler */
1297 static void
1298 kretprobe_perf_func(struct trace_kprobe *tk, struct kretprobe_instance *ri,
1299 struct pt_regs *regs)
1300 {
1301 struct trace_event_call *call = &tk->tp.call;
1302 struct kretprobe_trace_entry_head *entry;
1303 struct hlist_head *head;
1304 int size, __size, dsize;
1305 int rctx;
1306
1307 if (bpf_prog_array_valid(call) && !trace_call_bpf(call, regs))
1308 return;
1309
1310 head = this_cpu_ptr(call->perf_events);
1311 if (hlist_empty(head))
1312 return;
1313
1314 dsize = __get_data_size(&tk->tp, regs);
1315 __size = sizeof(*entry) + tk->tp.size + dsize;
1316 size = ALIGN(__size + sizeof(u32), sizeof(u64));
1317 size -= sizeof(u32);
1318
1319 entry = perf_trace_buf_alloc(size, NULL, &rctx);
1320 if (!entry)
1321 return;
1322
1323 entry->func = (unsigned long)tk->rp.kp.addr;
1324 entry->ret_ip = (unsigned long)ri->ret_addr;
1325 store_trace_args(sizeof(*entry), &tk->tp, regs, (u8 *)&entry[1], dsize);
1326 perf_trace_buf_submit(entry, size, rctx, call->event.type, 1, regs,
1327 head, NULL);
1328 }
1329 NOKPROBE_SYMBOL(kretprobe_perf_func);
1330
1331 int bpf_get_kprobe_info(const struct perf_event *event, u32 *fd_type,
1332 const char **symbol, u64 *probe_offset,
1333 u64 *probe_addr, bool perf_type_tracepoint)
1334 {
1335 const char *pevent = trace_event_name(event->tp_event);
1336 const char *group = event->tp_event->class->system;
1337 struct trace_kprobe *tk;
1338
1339 if (perf_type_tracepoint)
1340 tk = find_trace_kprobe(pevent, group);
1341 else
1342 tk = event->tp_event->data;
1343 if (!tk)
1344 return -EINVAL;
1345
1346 *fd_type = trace_kprobe_is_return(tk) ? BPF_FD_TYPE_KRETPROBE
1347 : BPF_FD_TYPE_KPROBE;
1348 if (tk->symbol) {
1349 *symbol = tk->symbol;
1350 *probe_offset = tk->rp.kp.offset;
1351 *probe_addr = 0;
1352 } else {
1353 *symbol = NULL;
1354 *probe_offset = 0;
1355 *probe_addr = (unsigned long)tk->rp.kp.addr;
1356 }
1357 return 0;
1358 }
1359 #endif /* CONFIG_PERF_EVENTS */
1360
1361 /*
1362 * called by perf_trace_init() or __ftrace_set_clr_event() under event_mutex.
1363 *
1364 * kprobe_trace_self_tests_init() does enable_trace_probe/disable_trace_probe
1365 * lockless, but we can't race with this __init function.
1366 */
1367 static int kprobe_register(struct trace_event_call *event,
1368 enum trace_reg type, void *data)
1369 {
1370 struct trace_kprobe *tk = (struct trace_kprobe *)event->data;
1371 struct trace_event_file *file = data;
1372
1373 switch (type) {
1374 case TRACE_REG_REGISTER:
1375 return enable_trace_kprobe(tk, file);
1376 case TRACE_REG_UNREGISTER:
1377 return disable_trace_kprobe(tk, file);
1378
1379 #ifdef CONFIG_PERF_EVENTS
1380 case TRACE_REG_PERF_REGISTER:
1381 return enable_trace_kprobe(tk, NULL);
1382 case TRACE_REG_PERF_UNREGISTER:
1383 return disable_trace_kprobe(tk, NULL);
1384 case TRACE_REG_PERF_OPEN:
1385 case TRACE_REG_PERF_CLOSE:
1386 case TRACE_REG_PERF_ADD:
1387 case TRACE_REG_PERF_DEL:
1388 return 0;
1389 #endif
1390 }
1391 return 0;
1392 }
1393
1394 static int kprobe_dispatcher(struct kprobe *kp, struct pt_regs *regs)
1395 {
1396 struct trace_kprobe *tk = container_of(kp, struct trace_kprobe, rp.kp);
1397 int ret = 0;
1398
1399 raw_cpu_inc(*tk->nhit);
1400
1401 if (tk->tp.flags & TP_FLAG_TRACE)
1402 kprobe_trace_func(tk, regs);
1403 #ifdef CONFIG_PERF_EVENTS
1404 if (tk->tp.flags & TP_FLAG_PROFILE)
1405 ret = kprobe_perf_func(tk, regs);
1406 #endif
1407 return ret;
1408 }
1409 NOKPROBE_SYMBOL(kprobe_dispatcher);
1410
1411 static int
1412 kretprobe_dispatcher(struct kretprobe_instance *ri, struct pt_regs *regs)
1413 {
1414 struct trace_kprobe *tk = container_of(ri->rp, struct trace_kprobe, rp);
1415
1416 raw_cpu_inc(*tk->nhit);
1417
1418 if (tk->tp.flags & TP_FLAG_TRACE)
1419 kretprobe_trace_func(tk, ri, regs);
1420 #ifdef CONFIG_PERF_EVENTS
1421 if (tk->tp.flags & TP_FLAG_PROFILE)
1422 kretprobe_perf_func(tk, ri, regs);
1423 #endif
1424 return 0; /* We don't tweek kernel, so just return 0 */
1425 }
1426 NOKPROBE_SYMBOL(kretprobe_dispatcher);
1427
1428 static struct trace_event_functions kretprobe_funcs = {
1429 .trace = print_kretprobe_event
1430 };
1431
1432 static struct trace_event_functions kprobe_funcs = {
1433 .trace = print_kprobe_event
1434 };
1435
1436 static inline void init_trace_event_call(struct trace_kprobe *tk,
1437 struct trace_event_call *call)
1438 {
1439 INIT_LIST_HEAD(&call->class->fields);
1440 if (trace_kprobe_is_return(tk)) {
1441 call->event.funcs = &kretprobe_funcs;
1442 call->class->define_fields = kretprobe_event_define_fields;
1443 } else {
1444 call->event.funcs = &kprobe_funcs;
1445 call->class->define_fields = kprobe_event_define_fields;
1446 }
1447
1448 call->flags = TRACE_EVENT_FL_KPROBE;
1449 call->class->reg = kprobe_register;
1450 call->data = tk;
1451 }
1452
1453 static int register_kprobe_event(struct trace_kprobe *tk)
1454 {
1455 struct trace_event_call *call = &tk->tp.call;
1456 int ret = 0;
1457
1458 init_trace_event_call(tk, call);
1459
1460 if (set_print_fmt(&tk->tp, trace_kprobe_is_return(tk)) < 0)
1461 return -ENOMEM;
1462 ret = register_trace_event(&call->event);
1463 if (!ret) {
1464 kfree(call->print_fmt);
1465 return -ENODEV;
1466 }
1467 ret = trace_add_event_call(call);
1468 if (ret) {
1469 pr_info("Failed to register kprobe event: %s\n",
1470 trace_event_name(call));
1471 kfree(call->print_fmt);
1472 unregister_trace_event(&call->event);
1473 }
1474 return ret;
1475 }
1476
1477 static int unregister_kprobe_event(struct trace_kprobe *tk)
1478 {
1479 int ret;
1480
1481 /* tp->event is unregistered in trace_remove_event_call() */
1482 ret = trace_remove_event_call(&tk->tp.call);
1483 if (!ret)
1484 kfree(tk->tp.call.print_fmt);
1485 return ret;
1486 }
1487
1488 #ifdef CONFIG_PERF_EVENTS
1489 /* create a trace_kprobe, but don't add it to global lists */
1490 struct trace_event_call *
1491 create_local_trace_kprobe(char *func, void *addr, unsigned long offs,
1492 bool is_return)
1493 {
1494 struct trace_kprobe *tk;
1495 int ret;
1496 char *event;
1497
1498 /*
1499 * local trace_kprobes are not added to probe_list, so they are never
1500 * searched in find_trace_kprobe(). Therefore, there is no concern of
1501 * duplicated name here.
1502 */
1503 event = func ? func : "DUMMY_EVENT";
1504
1505 tk = alloc_trace_kprobe(KPROBE_EVENT_SYSTEM, event, (void *)addr, func,
1506 offs, 0 /* maxactive */, 0 /* nargs */,
1507 is_return);
1508
1509 if (IS_ERR(tk)) {
1510 pr_info("Failed to allocate trace_probe.(%d)\n",
1511 (int)PTR_ERR(tk));
1512 return ERR_CAST(tk);
1513 }
1514
1515 init_trace_event_call(tk, &tk->tp.call);
1516
1517 if (set_print_fmt(&tk->tp, trace_kprobe_is_return(tk)) < 0) {
1518 ret = -ENOMEM;
1519 goto error;
1520 }
1521
1522 ret = __register_trace_kprobe(tk);
1523 if (ret < 0) {
1524 kfree(tk->tp.call.print_fmt);
1525 goto error;
1526 }
1527
1528 return &tk->tp.call;
1529 error:
1530 free_trace_kprobe(tk);
1531 return ERR_PTR(ret);
1532 }
1533
1534 void destroy_local_trace_kprobe(struct trace_event_call *event_call)
1535 {
1536 struct trace_kprobe *tk;
1537
1538 tk = container_of(event_call, struct trace_kprobe, tp.call);
1539
1540 if (trace_probe_is_enabled(&tk->tp)) {
1541 WARN_ON(1);
1542 return;
1543 }
1544
1545 __unregister_trace_kprobe(tk);
1546
1547 kfree(tk->tp.call.print_fmt);
1548 free_trace_kprobe(tk);
1549 }
1550 #endif /* CONFIG_PERF_EVENTS */
1551
1552 /* Make a tracefs interface for controlling probe points */
1553 static __init int init_kprobe_trace(void)
1554 {
1555 struct dentry *d_tracer;
1556 struct dentry *entry;
1557
1558 if (register_module_notifier(&trace_kprobe_module_nb))
1559 return -EINVAL;
1560
1561 d_tracer = tracing_init_dentry();
1562 if (IS_ERR(d_tracer))
1563 return 0;
1564
1565 entry = tracefs_create_file("kprobe_events", 0644, d_tracer,
1566 NULL, &kprobe_events_ops);
1567
1568 /* Event list interface */
1569 if (!entry)
1570 pr_warn("Could not create tracefs 'kprobe_events' entry\n");
1571
1572 /* Profile interface */
1573 entry = tracefs_create_file("kprobe_profile", 0444, d_tracer,
1574 NULL, &kprobe_profile_ops);
1575
1576 if (!entry)
1577 pr_warn("Could not create tracefs 'kprobe_profile' entry\n");
1578 return 0;
1579 }
1580 fs_initcall(init_kprobe_trace);
1581
1582
1583 #ifdef CONFIG_FTRACE_STARTUP_TEST
1584 static __init struct trace_event_file *
1585 find_trace_probe_file(struct trace_kprobe *tk, struct trace_array *tr)
1586 {
1587 struct trace_event_file *file;
1588
1589 list_for_each_entry(file, &tr->events, list)
1590 if (file->event_call == &tk->tp.call)
1591 return file;
1592
1593 return NULL;
1594 }
1595
1596 /*
1597 * Nobody but us can call enable_trace_kprobe/disable_trace_kprobe at this
1598 * stage, we can do this lockless.
1599 */
1600 static __init int kprobe_trace_self_tests_init(void)
1601 {
1602 int ret, warn = 0;
1603 int (*target)(int, int, int, int, int, int);
1604 struct trace_kprobe *tk;
1605 struct trace_event_file *file;
1606
1607 if (tracing_is_disabled())
1608 return -ENODEV;
1609
1610 target = kprobe_trace_selftest_target;
1611
1612 pr_info("Testing kprobe tracing: ");
1613
1614 ret = trace_run_command("p:testprobe kprobe_trace_selftest_target "
1615 "$stack $stack0 +0($stack)",
1616 create_trace_kprobe);
1617 if (WARN_ON_ONCE(ret)) {
1618 pr_warn("error on probing function entry.\n");
1619 warn++;
1620 } else {
1621 /* Enable trace point */
1622 tk = find_trace_kprobe("testprobe", KPROBE_EVENT_SYSTEM);
1623 if (WARN_ON_ONCE(tk == NULL)) {
1624 pr_warn("error on getting new probe.\n");
1625 warn++;
1626 } else {
1627 file = find_trace_probe_file(tk, top_trace_array());
1628 if (WARN_ON_ONCE(file == NULL)) {
1629 pr_warn("error on getting probe file.\n");
1630 warn++;
1631 } else
1632 enable_trace_kprobe(tk, file);
1633 }
1634 }
1635
1636 ret = trace_run_command("r:testprobe2 kprobe_trace_selftest_target "
1637 "$retval", create_trace_kprobe);
1638 if (WARN_ON_ONCE(ret)) {
1639 pr_warn("error on probing function return.\n");
1640 warn++;
1641 } else {
1642 /* Enable trace point */
1643 tk = find_trace_kprobe("testprobe2", KPROBE_EVENT_SYSTEM);
1644 if (WARN_ON_ONCE(tk == NULL)) {
1645 pr_warn("error on getting 2nd new probe.\n");
1646 warn++;
1647 } else {
1648 file = find_trace_probe_file(tk, top_trace_array());
1649 if (WARN_ON_ONCE(file == NULL)) {
1650 pr_warn("error on getting probe file.\n");
1651 warn++;
1652 } else
1653 enable_trace_kprobe(tk, file);
1654 }
1655 }
1656
1657 if (warn)
1658 goto end;
1659
1660 ret = target(1, 2, 3, 4, 5, 6);
1661
1662 /*
1663 * Not expecting an error here, the check is only to prevent the
1664 * optimizer from removing the call to target() as otherwise there
1665 * are no side-effects and the call is never performed.
1666 */
1667 if (ret != 21)
1668 warn++;
1669
1670 /* Disable trace points before removing it */
1671 tk = find_trace_kprobe("testprobe", KPROBE_EVENT_SYSTEM);
1672 if (WARN_ON_ONCE(tk == NULL)) {
1673 pr_warn("error on getting test probe.\n");
1674 warn++;
1675 } else {
1676 if (trace_kprobe_nhit(tk) != 1) {
1677 pr_warn("incorrect number of testprobe hits\n");
1678 warn++;
1679 }
1680
1681 file = find_trace_probe_file(tk, top_trace_array());
1682 if (WARN_ON_ONCE(file == NULL)) {
1683 pr_warn("error on getting probe file.\n");
1684 warn++;
1685 } else
1686 disable_trace_kprobe(tk, file);
1687 }
1688
1689 tk = find_trace_kprobe("testprobe2", KPROBE_EVENT_SYSTEM);
1690 if (WARN_ON_ONCE(tk == NULL)) {
1691 pr_warn("error on getting 2nd test probe.\n");
1692 warn++;
1693 } else {
1694 if (trace_kprobe_nhit(tk) != 1) {
1695 pr_warn("incorrect number of testprobe2 hits\n");
1696 warn++;
1697 }
1698
1699 file = find_trace_probe_file(tk, top_trace_array());
1700 if (WARN_ON_ONCE(file == NULL)) {
1701 pr_warn("error on getting probe file.\n");
1702 warn++;
1703 } else
1704 disable_trace_kprobe(tk, file);
1705 }
1706
1707 ret = trace_run_command("-:testprobe", create_trace_kprobe);
1708 if (WARN_ON_ONCE(ret)) {
1709 pr_warn("error on deleting a probe.\n");
1710 warn++;
1711 }
1712
1713 ret = trace_run_command("-:testprobe2", create_trace_kprobe);
1714 if (WARN_ON_ONCE(ret)) {
1715 pr_warn("error on deleting a probe.\n");
1716 warn++;
1717 }
1718
1719 end:
1720 release_all_trace_kprobes();
1721 /*
1722 * Wait for the optimizer work to finish. Otherwise it might fiddle
1723 * with probes in already freed __init text.
1724 */
1725 wait_for_kprobe_optimizer();
1726 if (warn)
1727 pr_cont("NG: Some tests are failed. Please check them.\n");
1728 else
1729 pr_cont("OK\n");
1730 return 0;
1731 }
1732
1733 late_initcall(kprobe_trace_self_tests_init);
1734
1735 #endif
Linux with added FPC-III support