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