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1 | /* |
2 | * uprobes-based tracing events | |
3 | * | |
4 | * This program is free software; you can redistribute it and/or modify | |
5 | * it under the terms of the GNU General Public License version 2 as | |
6 | * published by the Free Software Foundation. | |
7 | * | |
8 | * This program is distributed in the hope that it will be useful, | |
9 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
10 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
11 | * GNU General Public License for more details. | |
12 | * | |
13 | * You should have received a copy of the GNU General Public License | |
14 | * along with this program; if not, write to the Free Software | |
15 | * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA | |
16 | * | |
17 | * Copyright (C) IBM Corporation, 2010-2012 | |
18 | * Author: Srikar Dronamraju <srikar@linux.vnet.ibm.com> | |
19 | */ | |
20 | ||
21 | #include <linux/module.h> | |
22 | #include <linux/uaccess.h> | |
23 | #include <linux/uprobes.h> | |
24 | #include <linux/namei.h> | |
25 | ||
26 | #include "trace_probe.h" | |
27 | ||
28 | #define UPROBE_EVENT_SYSTEM "uprobes" | |
29 | ||
30 | /* | |
31 | * uprobe event core functions | |
32 | */ | |
33 | struct trace_uprobe; | |
34 | struct uprobe_trace_consumer { | |
35 | struct uprobe_consumer cons; | |
36 | struct trace_uprobe *tu; | |
37 | }; | |
38 | ||
39 | struct trace_uprobe { | |
40 | struct list_head list; | |
41 | struct ftrace_event_class class; | |
42 | struct ftrace_event_call call; | |
43 | struct uprobe_trace_consumer *consumer; | |
44 | struct inode *inode; | |
45 | char *filename; | |
46 | unsigned long offset; | |
47 | unsigned long nhit; | |
48 | unsigned int flags; /* For TP_FLAG_* */ | |
49 | ssize_t size; /* trace entry size */ | |
50 | unsigned int nr_args; | |
51 | struct probe_arg args[]; | |
52 | }; | |
53 | ||
54 | #define SIZEOF_TRACE_UPROBE(n) \ | |
55 | (offsetof(struct trace_uprobe, args) + \ | |
56 | (sizeof(struct probe_arg) * (n))) | |
57 | ||
58 | static int register_uprobe_event(struct trace_uprobe *tu); | |
59 | static void unregister_uprobe_event(struct trace_uprobe *tu); | |
60 | ||
61 | static DEFINE_MUTEX(uprobe_lock); | |
62 | static LIST_HEAD(uprobe_list); | |
63 | ||
64 | static int uprobe_dispatcher(struct uprobe_consumer *con, struct pt_regs *regs); | |
65 | ||
66 | /* | |
67 | * Allocate new trace_uprobe and initialize it (including uprobes). | |
68 | */ | |
69 | static struct trace_uprobe * | |
70 | alloc_trace_uprobe(const char *group, const char *event, int nargs) | |
71 | { | |
72 | struct trace_uprobe *tu; | |
73 | ||
74 | if (!event || !is_good_name(event)) | |
75 | return ERR_PTR(-EINVAL); | |
76 | ||
77 | if (!group || !is_good_name(group)) | |
78 | return ERR_PTR(-EINVAL); | |
79 | ||
80 | tu = kzalloc(SIZEOF_TRACE_UPROBE(nargs), GFP_KERNEL); | |
81 | if (!tu) | |
82 | return ERR_PTR(-ENOMEM); | |
83 | ||
84 | tu->call.class = &tu->class; | |
85 | tu->call.name = kstrdup(event, GFP_KERNEL); | |
86 | if (!tu->call.name) | |
87 | goto error; | |
88 | ||
89 | tu->class.system = kstrdup(group, GFP_KERNEL); | |
90 | if (!tu->class.system) | |
91 | goto error; | |
92 | ||
93 | INIT_LIST_HEAD(&tu->list); | |
94 | return tu; | |
95 | ||
96 | error: | |
97 | kfree(tu->call.name); | |
98 | kfree(tu); | |
99 | ||
100 | return ERR_PTR(-ENOMEM); | |
101 | } | |
102 | ||
103 | static void free_trace_uprobe(struct trace_uprobe *tu) | |
104 | { | |
105 | int i; | |
106 | ||
107 | for (i = 0; i < tu->nr_args; i++) | |
108 | traceprobe_free_probe_arg(&tu->args[i]); | |
109 | ||
110 | iput(tu->inode); | |
111 | kfree(tu->call.class->system); | |
112 | kfree(tu->call.name); | |
113 | kfree(tu->filename); | |
114 | kfree(tu); | |
115 | } | |
116 | ||
117 | static struct trace_uprobe *find_probe_event(const char *event, const char *group) | |
118 | { | |
119 | struct trace_uprobe *tu; | |
120 | ||
121 | list_for_each_entry(tu, &uprobe_list, list) | |
122 | if (strcmp(tu->call.name, event) == 0 && | |
123 | strcmp(tu->call.class->system, group) == 0) | |
124 | return tu; | |
125 | ||
126 | return NULL; | |
127 | } | |
128 | ||
129 | /* Unregister a trace_uprobe and probe_event: call with locking uprobe_lock */ | |
130 | static void unregister_trace_uprobe(struct trace_uprobe *tu) | |
131 | { | |
132 | list_del(&tu->list); | |
133 | unregister_uprobe_event(tu); | |
134 | free_trace_uprobe(tu); | |
135 | } | |
136 | ||
137 | /* Register a trace_uprobe and probe_event */ | |
138 | static int register_trace_uprobe(struct trace_uprobe *tu) | |
139 | { | |
140 | struct trace_uprobe *old_tp; | |
141 | int ret; | |
142 | ||
143 | mutex_lock(&uprobe_lock); | |
144 | ||
145 | /* register as an event */ | |
146 | old_tp = find_probe_event(tu->call.name, tu->call.class->system); | |
147 | if (old_tp) | |
148 | /* delete old event */ | |
149 | unregister_trace_uprobe(old_tp); | |
150 | ||
151 | ret = register_uprobe_event(tu); | |
152 | if (ret) { | |
153 | pr_warning("Failed to register probe event(%d)\n", ret); | |
154 | goto end; | |
155 | } | |
156 | ||
157 | list_add_tail(&tu->list, &uprobe_list); | |
158 | ||
159 | end: | |
160 | mutex_unlock(&uprobe_lock); | |
161 | ||
162 | return ret; | |
163 | } | |
164 | ||
165 | /* | |
166 | * Argument syntax: | |
167 | * - Add uprobe: p[:[GRP/]EVENT] PATH:SYMBOL[+offs] [FETCHARGS] | |
168 | * | |
169 | * - Remove uprobe: -:[GRP/]EVENT | |
170 | */ | |
171 | static int create_trace_uprobe(int argc, char **argv) | |
172 | { | |
173 | struct trace_uprobe *tu; | |
174 | struct inode *inode; | |
175 | char *arg, *event, *group, *filename; | |
176 | char buf[MAX_EVENT_NAME_LEN]; | |
177 | struct path path; | |
178 | unsigned long offset; | |
179 | bool is_delete; | |
180 | int i, ret; | |
181 | ||
182 | inode = NULL; | |
183 | ret = 0; | |
184 | is_delete = false; | |
185 | event = NULL; | |
186 | group = NULL; | |
187 | ||
188 | /* argc must be >= 1 */ | |
189 | if (argv[0][0] == '-') | |
190 | is_delete = true; | |
191 | else if (argv[0][0] != 'p') { | |
192 | pr_info("Probe definition must be started with 'p', 'r' or" " '-'.\n"); | |
193 | return -EINVAL; | |
194 | } | |
195 | ||
196 | if (argv[0][1] == ':') { | |
197 | event = &argv[0][2]; | |
198 | arg = strchr(event, '/'); | |
199 | ||
200 | if (arg) { | |
201 | group = event; | |
202 | event = arg + 1; | |
203 | event[-1] = '\0'; | |
204 | ||
205 | if (strlen(group) == 0) { | |
206 | pr_info("Group name is not specified\n"); | |
207 | return -EINVAL; | |
208 | } | |
209 | } | |
210 | if (strlen(event) == 0) { | |
211 | pr_info("Event name is not specified\n"); | |
212 | return -EINVAL; | |
213 | } | |
214 | } | |
215 | if (!group) | |
216 | group = UPROBE_EVENT_SYSTEM; | |
217 | ||
218 | if (is_delete) { | |
219 | if (!event) { | |
220 | pr_info("Delete command needs an event name.\n"); | |
221 | return -EINVAL; | |
222 | } | |
223 | mutex_lock(&uprobe_lock); | |
224 | tu = find_probe_event(event, group); | |
225 | ||
226 | if (!tu) { | |
227 | mutex_unlock(&uprobe_lock); | |
228 | pr_info("Event %s/%s doesn't exist.\n", group, event); | |
229 | return -ENOENT; | |
230 | } | |
231 | /* delete an event */ | |
232 | unregister_trace_uprobe(tu); | |
233 | mutex_unlock(&uprobe_lock); | |
234 | return 0; | |
235 | } | |
236 | ||
237 | if (argc < 2) { | |
238 | pr_info("Probe point is not specified.\n"); | |
239 | return -EINVAL; | |
240 | } | |
241 | if (isdigit(argv[1][0])) { | |
242 | pr_info("probe point must be have a filename.\n"); | |
243 | return -EINVAL; | |
244 | } | |
245 | arg = strchr(argv[1], ':'); | |
246 | if (!arg) | |
247 | goto fail_address_parse; | |
248 | ||
249 | *arg++ = '\0'; | |
250 | filename = argv[1]; | |
251 | ret = kern_path(filename, LOOKUP_FOLLOW, &path); | |
252 | if (ret) | |
253 | goto fail_address_parse; | |
254 | ||
255 | ret = strict_strtoul(arg, 0, &offset); | |
256 | if (ret) | |
257 | goto fail_address_parse; | |
258 | ||
259 | inode = igrab(path.dentry->d_inode); | |
260 | ||
261 | argc -= 2; | |
262 | argv += 2; | |
263 | ||
264 | /* setup a probe */ | |
265 | if (!event) { | |
266 | char *tail = strrchr(filename, '/'); | |
267 | char *ptr; | |
268 | ||
269 | ptr = kstrdup((tail ? tail + 1 : filename), GFP_KERNEL); | |
270 | if (!ptr) { | |
271 | ret = -ENOMEM; | |
272 | goto fail_address_parse; | |
273 | } | |
274 | ||
275 | tail = ptr; | |
276 | ptr = strpbrk(tail, ".-_"); | |
277 | if (ptr) | |
278 | *ptr = '\0'; | |
279 | ||
280 | snprintf(buf, MAX_EVENT_NAME_LEN, "%c_%s_0x%lx", 'p', tail, offset); | |
281 | event = buf; | |
282 | kfree(tail); | |
283 | } | |
284 | ||
285 | tu = alloc_trace_uprobe(group, event, argc); | |
286 | if (IS_ERR(tu)) { | |
287 | pr_info("Failed to allocate trace_uprobe.(%d)\n", (int)PTR_ERR(tu)); | |
288 | ret = PTR_ERR(tu); | |
289 | goto fail_address_parse; | |
290 | } | |
291 | tu->offset = offset; | |
292 | tu->inode = inode; | |
293 | tu->filename = kstrdup(filename, GFP_KERNEL); | |
294 | ||
295 | if (!tu->filename) { | |
296 | pr_info("Failed to allocate filename.\n"); | |
297 | ret = -ENOMEM; | |
298 | goto error; | |
299 | } | |
300 | ||
301 | /* parse arguments */ | |
302 | ret = 0; | |
303 | for (i = 0; i < argc && i < MAX_TRACE_ARGS; i++) { | |
304 | /* Increment count for freeing args in error case */ | |
305 | tu->nr_args++; | |
306 | ||
307 | /* Parse argument name */ | |
308 | arg = strchr(argv[i], '='); | |
309 | if (arg) { | |
310 | *arg++ = '\0'; | |
311 | tu->args[i].name = kstrdup(argv[i], GFP_KERNEL); | |
312 | } else { | |
313 | arg = argv[i]; | |
314 | /* If argument name is omitted, set "argN" */ | |
315 | snprintf(buf, MAX_EVENT_NAME_LEN, "arg%d", i + 1); | |
316 | tu->args[i].name = kstrdup(buf, GFP_KERNEL); | |
317 | } | |
318 | ||
319 | if (!tu->args[i].name) { | |
320 | pr_info("Failed to allocate argument[%d] name.\n", i); | |
321 | ret = -ENOMEM; | |
322 | goto error; | |
323 | } | |
324 | ||
325 | if (!is_good_name(tu->args[i].name)) { | |
326 | pr_info("Invalid argument[%d] name: %s\n", i, tu->args[i].name); | |
327 | ret = -EINVAL; | |
328 | goto error; | |
329 | } | |
330 | ||
331 | if (traceprobe_conflict_field_name(tu->args[i].name, tu->args, i)) { | |
332 | pr_info("Argument[%d] name '%s' conflicts with " | |
333 | "another field.\n", i, argv[i]); | |
334 | ret = -EINVAL; | |
335 | goto error; | |
336 | } | |
337 | ||
338 | /* Parse fetch argument */ | |
339 | ret = traceprobe_parse_probe_arg(arg, &tu->size, &tu->args[i], false, false); | |
340 | if (ret) { | |
341 | pr_info("Parse error at argument[%d]. (%d)\n", i, ret); | |
342 | goto error; | |
343 | } | |
344 | } | |
345 | ||
346 | ret = register_trace_uprobe(tu); | |
347 | if (ret) | |
348 | goto error; | |
349 | return 0; | |
350 | ||
351 | error: | |
352 | free_trace_uprobe(tu); | |
353 | return ret; | |
354 | ||
355 | fail_address_parse: | |
356 | if (inode) | |
357 | iput(inode); | |
358 | ||
359 | pr_info("Failed to parse address.\n"); | |
360 | ||
361 | return ret; | |
362 | } | |
363 | ||
364 | static void cleanup_all_probes(void) | |
365 | { | |
366 | struct trace_uprobe *tu; | |
367 | ||
368 | mutex_lock(&uprobe_lock); | |
369 | while (!list_empty(&uprobe_list)) { | |
370 | tu = list_entry(uprobe_list.next, struct trace_uprobe, list); | |
371 | unregister_trace_uprobe(tu); | |
372 | } | |
373 | mutex_unlock(&uprobe_lock); | |
374 | } | |
375 | ||
376 | /* Probes listing interfaces */ | |
377 | static void *probes_seq_start(struct seq_file *m, loff_t *pos) | |
378 | { | |
379 | mutex_lock(&uprobe_lock); | |
380 | return seq_list_start(&uprobe_list, *pos); | |
381 | } | |
382 | ||
383 | static void *probes_seq_next(struct seq_file *m, void *v, loff_t *pos) | |
384 | { | |
385 | return seq_list_next(v, &uprobe_list, pos); | |
386 | } | |
387 | ||
388 | static void probes_seq_stop(struct seq_file *m, void *v) | |
389 | { | |
390 | mutex_unlock(&uprobe_lock); | |
391 | } | |
392 | ||
393 | static int probes_seq_show(struct seq_file *m, void *v) | |
394 | { | |
395 | struct trace_uprobe *tu = v; | |
396 | int i; | |
397 | ||
398 | seq_printf(m, "p:%s/%s", tu->call.class->system, tu->call.name); | |
399 | seq_printf(m, " %s:0x%p", tu->filename, (void *)tu->offset); | |
400 | ||
401 | for (i = 0; i < tu->nr_args; i++) | |
402 | seq_printf(m, " %s=%s", tu->args[i].name, tu->args[i].comm); | |
403 | ||
404 | seq_printf(m, "\n"); | |
405 | return 0; | |
406 | } | |
407 | ||
408 | static const struct seq_operations probes_seq_op = { | |
409 | .start = probes_seq_start, | |
410 | .next = probes_seq_next, | |
411 | .stop = probes_seq_stop, | |
412 | .show = probes_seq_show | |
413 | }; | |
414 | ||
415 | static int probes_open(struct inode *inode, struct file *file) | |
416 | { | |
417 | if ((file->f_mode & FMODE_WRITE) && (file->f_flags & O_TRUNC)) | |
418 | cleanup_all_probes(); | |
419 | ||
420 | return seq_open(file, &probes_seq_op); | |
421 | } | |
422 | ||
423 | static ssize_t probes_write(struct file *file, const char __user *buffer, | |
424 | size_t count, loff_t *ppos) | |
425 | { | |
426 | return traceprobe_probes_write(file, buffer, count, ppos, create_trace_uprobe); | |
427 | } | |
428 | ||
429 | static const struct file_operations uprobe_events_ops = { | |
430 | .owner = THIS_MODULE, | |
431 | .open = probes_open, | |
432 | .read = seq_read, | |
433 | .llseek = seq_lseek, | |
434 | .release = seq_release, | |
435 | .write = probes_write, | |
436 | }; | |
437 | ||
438 | /* Probes profiling interfaces */ | |
439 | static int probes_profile_seq_show(struct seq_file *m, void *v) | |
440 | { | |
441 | struct trace_uprobe *tu = v; | |
442 | ||
443 | seq_printf(m, " %s %-44s %15lu\n", tu->filename, tu->call.name, tu->nhit); | |
444 | return 0; | |
445 | } | |
446 | ||
447 | static const struct seq_operations profile_seq_op = { | |
448 | .start = probes_seq_start, | |
449 | .next = probes_seq_next, | |
450 | .stop = probes_seq_stop, | |
451 | .show = probes_profile_seq_show | |
452 | }; | |
453 | ||
454 | static int profile_open(struct inode *inode, struct file *file) | |
455 | { | |
456 | return seq_open(file, &profile_seq_op); | |
457 | } | |
458 | ||
459 | static const struct file_operations uprobe_profile_ops = { | |
460 | .owner = THIS_MODULE, | |
461 | .open = profile_open, | |
462 | .read = seq_read, | |
463 | .llseek = seq_lseek, | |
464 | .release = seq_release, | |
465 | }; | |
466 | ||
467 | /* uprobe handler */ | |
468 | static void uprobe_trace_func(struct trace_uprobe *tu, struct pt_regs *regs) | |
469 | { | |
470 | struct uprobe_trace_entry_head *entry; | |
471 | struct ring_buffer_event *event; | |
472 | struct ring_buffer *buffer; | |
473 | u8 *data; | |
474 | int size, i, pc; | |
475 | unsigned long irq_flags; | |
476 | struct ftrace_event_call *call = &tu->call; | |
477 | ||
478 | tu->nhit++; | |
479 | ||
480 | local_save_flags(irq_flags); | |
481 | pc = preempt_count(); | |
482 | ||
483 | size = sizeof(*entry) + tu->size; | |
484 | ||
485 | event = trace_current_buffer_lock_reserve(&buffer, call->event.type, | |
486 | size, irq_flags, pc); | |
487 | if (!event) | |
488 | return; | |
489 | ||
490 | entry = ring_buffer_event_data(event); | |
491 | entry->ip = uprobe_get_swbp_addr(task_pt_regs(current)); | |
492 | data = (u8 *)&entry[1]; | |
493 | for (i = 0; i < tu->nr_args; i++) | |
494 | call_fetch(&tu->args[i].fetch, regs, data + tu->args[i].offset); | |
495 | ||
496 | if (!filter_current_check_discard(buffer, call, entry, event)) | |
497 | trace_buffer_unlock_commit(buffer, event, irq_flags, pc); | |
498 | } | |
499 | ||
500 | /* Event entry printers */ | |
501 | static enum print_line_t | |
502 | print_uprobe_event(struct trace_iterator *iter, int flags, struct trace_event *event) | |
503 | { | |
504 | struct uprobe_trace_entry_head *field; | |
505 | struct trace_seq *s = &iter->seq; | |
506 | struct trace_uprobe *tu; | |
507 | u8 *data; | |
508 | int i; | |
509 | ||
510 | field = (struct uprobe_trace_entry_head *)iter->ent; | |
511 | tu = container_of(event, struct trace_uprobe, call.event); | |
512 | ||
513 | if (!trace_seq_printf(s, "%s: (", tu->call.name)) | |
514 | goto partial; | |
515 | ||
516 | if (!seq_print_ip_sym(s, field->ip, flags | TRACE_ITER_SYM_OFFSET)) | |
517 | goto partial; | |
518 | ||
519 | if (!trace_seq_puts(s, ")")) | |
520 | goto partial; | |
521 | ||
522 | data = (u8 *)&field[1]; | |
523 | for (i = 0; i < tu->nr_args; i++) { | |
524 | if (!tu->args[i].type->print(s, tu->args[i].name, | |
525 | data + tu->args[i].offset, field)) | |
526 | goto partial; | |
527 | } | |
528 | ||
529 | if (trace_seq_puts(s, "\n")) | |
530 | return TRACE_TYPE_HANDLED; | |
531 | ||
532 | partial: | |
533 | return TRACE_TYPE_PARTIAL_LINE; | |
534 | } | |
535 | ||
536 | static int probe_event_enable(struct trace_uprobe *tu, int flag) | |
537 | { | |
538 | struct uprobe_trace_consumer *utc; | |
539 | int ret = 0; | |
540 | ||
541 | if (!tu->inode || tu->consumer) | |
542 | return -EINTR; | |
543 | ||
544 | utc = kzalloc(sizeof(struct uprobe_trace_consumer), GFP_KERNEL); | |
545 | if (!utc) | |
546 | return -EINTR; | |
547 | ||
548 | utc->cons.handler = uprobe_dispatcher; | |
549 | utc->cons.filter = NULL; | |
550 | ret = uprobe_register(tu->inode, tu->offset, &utc->cons); | |
551 | if (ret) { | |
552 | kfree(utc); | |
553 | return ret; | |
554 | } | |
555 | ||
556 | tu->flags |= flag; | |
557 | utc->tu = tu; | |
558 | tu->consumer = utc; | |
559 | ||
560 | return 0; | |
561 | } | |
562 | ||
563 | static void probe_event_disable(struct trace_uprobe *tu, int flag) | |
564 | { | |
565 | if (!tu->inode || !tu->consumer) | |
566 | return; | |
567 | ||
568 | uprobe_unregister(tu->inode, tu->offset, &tu->consumer->cons); | |
569 | tu->flags &= ~flag; | |
570 | kfree(tu->consumer); | |
571 | tu->consumer = NULL; | |
572 | } | |
573 | ||
574 | static int uprobe_event_define_fields(struct ftrace_event_call *event_call) | |
575 | { | |
576 | int ret, i; | |
577 | struct uprobe_trace_entry_head field; | |
578 | struct trace_uprobe *tu = (struct trace_uprobe *)event_call->data; | |
579 | ||
580 | DEFINE_FIELD(unsigned long, ip, FIELD_STRING_IP, 0); | |
581 | /* Set argument names as fields */ | |
582 | for (i = 0; i < tu->nr_args; i++) { | |
583 | ret = trace_define_field(event_call, tu->args[i].type->fmttype, | |
584 | tu->args[i].name, | |
585 | sizeof(field) + tu->args[i].offset, | |
586 | tu->args[i].type->size, | |
587 | tu->args[i].type->is_signed, | |
588 | FILTER_OTHER); | |
589 | ||
590 | if (ret) | |
591 | return ret; | |
592 | } | |
593 | return 0; | |
594 | } | |
595 | ||
596 | #define LEN_OR_ZERO (len ? len - pos : 0) | |
597 | static int __set_print_fmt(struct trace_uprobe *tu, char *buf, int len) | |
598 | { | |
599 | const char *fmt, *arg; | |
600 | int i; | |
601 | int pos = 0; | |
602 | ||
603 | fmt = "(%lx)"; | |
604 | arg = "REC->" FIELD_STRING_IP; | |
605 | ||
606 | /* When len=0, we just calculate the needed length */ | |
607 | ||
608 | pos += snprintf(buf + pos, LEN_OR_ZERO, "\"%s", fmt); | |
609 | ||
610 | for (i = 0; i < tu->nr_args; i++) { | |
611 | pos += snprintf(buf + pos, LEN_OR_ZERO, " %s=%s", | |
612 | tu->args[i].name, tu->args[i].type->fmt); | |
613 | } | |
614 | ||
615 | pos += snprintf(buf + pos, LEN_OR_ZERO, "\", %s", arg); | |
616 | ||
617 | for (i = 0; i < tu->nr_args; i++) { | |
618 | pos += snprintf(buf + pos, LEN_OR_ZERO, ", REC->%s", | |
619 | tu->args[i].name); | |
620 | } | |
621 | ||
622 | return pos; /* return the length of print_fmt */ | |
623 | } | |
624 | #undef LEN_OR_ZERO | |
625 | ||
626 | static int set_print_fmt(struct trace_uprobe *tu) | |
627 | { | |
628 | char *print_fmt; | |
629 | int len; | |
630 | ||
631 | /* First: called with 0 length to calculate the needed length */ | |
632 | len = __set_print_fmt(tu, NULL, 0); | |
633 | print_fmt = kmalloc(len + 1, GFP_KERNEL); | |
634 | if (!print_fmt) | |
635 | return -ENOMEM; | |
636 | ||
637 | /* Second: actually write the @print_fmt */ | |
638 | __set_print_fmt(tu, print_fmt, len + 1); | |
639 | tu->call.print_fmt = print_fmt; | |
640 | ||
641 | return 0; | |
642 | } | |
643 | ||
644 | #ifdef CONFIG_PERF_EVENTS | |
645 | /* uprobe profile handler */ | |
646 | static void uprobe_perf_func(struct trace_uprobe *tu, struct pt_regs *regs) | |
647 | { | |
648 | struct ftrace_event_call *call = &tu->call; | |
649 | struct uprobe_trace_entry_head *entry; | |
650 | struct hlist_head *head; | |
651 | u8 *data; | |
652 | int size, __size, i; | |
653 | int rctx; | |
654 | ||
655 | __size = sizeof(*entry) + tu->size; | |
656 | size = ALIGN(__size + sizeof(u32), sizeof(u64)); | |
657 | size -= sizeof(u32); | |
658 | if (WARN_ONCE(size > PERF_MAX_TRACE_SIZE, "profile buffer not large enough")) | |
659 | return; | |
660 | ||
661 | preempt_disable(); | |
662 | ||
663 | entry = perf_trace_buf_prepare(size, call->event.type, regs, &rctx); | |
664 | if (!entry) | |
665 | goto out; | |
666 | ||
667 | entry->ip = uprobe_get_swbp_addr(task_pt_regs(current)); | |
668 | data = (u8 *)&entry[1]; | |
669 | for (i = 0; i < tu->nr_args; i++) | |
670 | call_fetch(&tu->args[i].fetch, regs, data + tu->args[i].offset); | |
671 | ||
672 | head = this_cpu_ptr(call->perf_events); | |
673 | perf_trace_buf_submit(entry, size, rctx, entry->ip, 1, regs, head); | |
674 | ||
675 | out: | |
676 | preempt_enable(); | |
677 | } | |
678 | #endif /* CONFIG_PERF_EVENTS */ | |
679 | ||
680 | static | |
681 | int trace_uprobe_register(struct ftrace_event_call *event, enum trace_reg type, void *data) | |
682 | { | |
683 | struct trace_uprobe *tu = (struct trace_uprobe *)event->data; | |
684 | ||
685 | switch (type) { | |
686 | case TRACE_REG_REGISTER: | |
687 | return probe_event_enable(tu, TP_FLAG_TRACE); | |
688 | ||
689 | case TRACE_REG_UNREGISTER: | |
690 | probe_event_disable(tu, TP_FLAG_TRACE); | |
691 | return 0; | |
692 | ||
693 | #ifdef CONFIG_PERF_EVENTS | |
694 | case TRACE_REG_PERF_REGISTER: | |
695 | return probe_event_enable(tu, TP_FLAG_PROFILE); | |
696 | ||
697 | case TRACE_REG_PERF_UNREGISTER: | |
698 | probe_event_disable(tu, TP_FLAG_PROFILE); | |
699 | return 0; | |
700 | #endif | |
701 | default: | |
702 | return 0; | |
703 | } | |
704 | return 0; | |
705 | } | |
706 | ||
707 | static int uprobe_dispatcher(struct uprobe_consumer *con, struct pt_regs *regs) | |
708 | { | |
709 | struct uprobe_trace_consumer *utc; | |
710 | struct trace_uprobe *tu; | |
711 | ||
712 | utc = container_of(con, struct uprobe_trace_consumer, cons); | |
713 | tu = utc->tu; | |
714 | if (!tu || tu->consumer != utc) | |
715 | return 0; | |
716 | ||
717 | if (tu->flags & TP_FLAG_TRACE) | |
718 | uprobe_trace_func(tu, regs); | |
719 | ||
720 | #ifdef CONFIG_PERF_EVENTS | |
721 | if (tu->flags & TP_FLAG_PROFILE) | |
722 | uprobe_perf_func(tu, regs); | |
723 | #endif | |
724 | return 0; | |
725 | } | |
726 | ||
727 | static struct trace_event_functions uprobe_funcs = { | |
728 | .trace = print_uprobe_event | |
729 | }; | |
730 | ||
731 | static int register_uprobe_event(struct trace_uprobe *tu) | |
732 | { | |
733 | struct ftrace_event_call *call = &tu->call; | |
734 | int ret; | |
735 | ||
736 | /* Initialize ftrace_event_call */ | |
737 | INIT_LIST_HEAD(&call->class->fields); | |
738 | call->event.funcs = &uprobe_funcs; | |
739 | call->class->define_fields = uprobe_event_define_fields; | |
740 | ||
741 | if (set_print_fmt(tu) < 0) | |
742 | return -ENOMEM; | |
743 | ||
744 | ret = register_ftrace_event(&call->event); | |
745 | if (!ret) { | |
746 | kfree(call->print_fmt); | |
747 | return -ENODEV; | |
748 | } | |
749 | call->flags = 0; | |
750 | call->class->reg = trace_uprobe_register; | |
751 | call->data = tu; | |
752 | ret = trace_add_event_call(call); | |
753 | ||
754 | if (ret) { | |
755 | pr_info("Failed to register uprobe event: %s\n", call->name); | |
756 | kfree(call->print_fmt); | |
757 | unregister_ftrace_event(&call->event); | |
758 | } | |
759 | ||
760 | return ret; | |
761 | } | |
762 | ||
763 | static void unregister_uprobe_event(struct trace_uprobe *tu) | |
764 | { | |
765 | /* tu->event is unregistered in trace_remove_event_call() */ | |
766 | trace_remove_event_call(&tu->call); | |
767 | kfree(tu->call.print_fmt); | |
768 | tu->call.print_fmt = NULL; | |
769 | } | |
770 | ||
771 | /* Make a trace interface for controling probe points */ | |
772 | static __init int init_uprobe_trace(void) | |
773 | { | |
774 | struct dentry *d_tracer; | |
775 | ||
776 | d_tracer = tracing_init_dentry(); | |
777 | if (!d_tracer) | |
778 | return 0; | |
779 | ||
780 | trace_create_file("uprobe_events", 0644, d_tracer, | |
781 | NULL, &uprobe_events_ops); | |
782 | /* Profile interface */ | |
783 | trace_create_file("uprobe_profile", 0444, d_tracer, | |
784 | NULL, &uprobe_profile_ops); | |
785 | return 0; | |
786 | } | |
787 | ||
788 | fs_initcall(init_uprobe_trace); |