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f3f096cf SD |
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> | |
b2e902f0 | 25 | #include <linux/string.h> |
f3f096cf SD |
26 | |
27 | #include "trace_probe.h" | |
28 | ||
29 | #define UPROBE_EVENT_SYSTEM "uprobes" | |
30 | ||
31 | /* | |
32 | * uprobe event core functions | |
33 | */ | |
34 | struct trace_uprobe; | |
35 | struct uprobe_trace_consumer { | |
36 | struct uprobe_consumer cons; | |
37 | struct trace_uprobe *tu; | |
38 | }; | |
39 | ||
40 | struct trace_uprobe { | |
41 | struct list_head list; | |
42 | struct ftrace_event_class class; | |
43 | struct ftrace_event_call call; | |
44 | struct uprobe_trace_consumer *consumer; | |
45 | struct inode *inode; | |
46 | char *filename; | |
47 | unsigned long offset; | |
48 | unsigned long nhit; | |
49 | unsigned int flags; /* For TP_FLAG_* */ | |
50 | ssize_t size; /* trace entry size */ | |
51 | unsigned int nr_args; | |
52 | struct probe_arg args[]; | |
53 | }; | |
54 | ||
55 | #define SIZEOF_TRACE_UPROBE(n) \ | |
56 | (offsetof(struct trace_uprobe, args) + \ | |
57 | (sizeof(struct probe_arg) * (n))) | |
58 | ||
59 | static int register_uprobe_event(struct trace_uprobe *tu); | |
60 | static void unregister_uprobe_event(struct trace_uprobe *tu); | |
61 | ||
62 | static DEFINE_MUTEX(uprobe_lock); | |
63 | static LIST_HEAD(uprobe_list); | |
64 | ||
65 | static int uprobe_dispatcher(struct uprobe_consumer *con, struct pt_regs *regs); | |
66 | ||
67 | /* | |
68 | * Allocate new trace_uprobe and initialize it (including uprobes). | |
69 | */ | |
70 | static struct trace_uprobe * | |
71 | alloc_trace_uprobe(const char *group, const char *event, int nargs) | |
72 | { | |
73 | struct trace_uprobe *tu; | |
74 | ||
75 | if (!event || !is_good_name(event)) | |
76 | return ERR_PTR(-EINVAL); | |
77 | ||
78 | if (!group || !is_good_name(group)) | |
79 | return ERR_PTR(-EINVAL); | |
80 | ||
81 | tu = kzalloc(SIZEOF_TRACE_UPROBE(nargs), GFP_KERNEL); | |
82 | if (!tu) | |
83 | return ERR_PTR(-ENOMEM); | |
84 | ||
85 | tu->call.class = &tu->class; | |
86 | tu->call.name = kstrdup(event, GFP_KERNEL); | |
87 | if (!tu->call.name) | |
88 | goto error; | |
89 | ||
90 | tu->class.system = kstrdup(group, GFP_KERNEL); | |
91 | if (!tu->class.system) | |
92 | goto error; | |
93 | ||
94 | INIT_LIST_HEAD(&tu->list); | |
95 | return tu; | |
96 | ||
97 | error: | |
98 | kfree(tu->call.name); | |
99 | kfree(tu); | |
100 | ||
101 | return ERR_PTR(-ENOMEM); | |
102 | } | |
103 | ||
104 | static void free_trace_uprobe(struct trace_uprobe *tu) | |
105 | { | |
106 | int i; | |
107 | ||
108 | for (i = 0; i < tu->nr_args; i++) | |
109 | traceprobe_free_probe_arg(&tu->args[i]); | |
110 | ||
111 | iput(tu->inode); | |
112 | kfree(tu->call.class->system); | |
113 | kfree(tu->call.name); | |
114 | kfree(tu->filename); | |
115 | kfree(tu); | |
116 | } | |
117 | ||
118 | static struct trace_uprobe *find_probe_event(const char *event, const char *group) | |
119 | { | |
120 | struct trace_uprobe *tu; | |
121 | ||
122 | list_for_each_entry(tu, &uprobe_list, list) | |
123 | if (strcmp(tu->call.name, event) == 0 && | |
124 | strcmp(tu->call.class->system, group) == 0) | |
125 | return tu; | |
126 | ||
127 | return NULL; | |
128 | } | |
129 | ||
130 | /* Unregister a trace_uprobe and probe_event: call with locking uprobe_lock */ | |
131 | static void unregister_trace_uprobe(struct trace_uprobe *tu) | |
132 | { | |
133 | list_del(&tu->list); | |
134 | unregister_uprobe_event(tu); | |
135 | free_trace_uprobe(tu); | |
136 | } | |
137 | ||
138 | /* Register a trace_uprobe and probe_event */ | |
139 | static int register_trace_uprobe(struct trace_uprobe *tu) | |
140 | { | |
141 | struct trace_uprobe *old_tp; | |
142 | int ret; | |
143 | ||
144 | mutex_lock(&uprobe_lock); | |
145 | ||
146 | /* register as an event */ | |
147 | old_tp = find_probe_event(tu->call.name, tu->call.class->system); | |
148 | if (old_tp) | |
149 | /* delete old event */ | |
150 | unregister_trace_uprobe(old_tp); | |
151 | ||
152 | ret = register_uprobe_event(tu); | |
153 | if (ret) { | |
154 | pr_warning("Failed to register probe event(%d)\n", ret); | |
155 | goto end; | |
156 | } | |
157 | ||
158 | list_add_tail(&tu->list, &uprobe_list); | |
159 | ||
160 | end: | |
161 | mutex_unlock(&uprobe_lock); | |
162 | ||
163 | return ret; | |
164 | } | |
165 | ||
166 | /* | |
167 | * Argument syntax: | |
168 | * - Add uprobe: p[:[GRP/]EVENT] PATH:SYMBOL[+offs] [FETCHARGS] | |
169 | * | |
170 | * - Remove uprobe: -:[GRP/]EVENT | |
171 | */ | |
172 | static int create_trace_uprobe(int argc, char **argv) | |
173 | { | |
174 | struct trace_uprobe *tu; | |
175 | struct inode *inode; | |
176 | char *arg, *event, *group, *filename; | |
177 | char buf[MAX_EVENT_NAME_LEN]; | |
178 | struct path path; | |
179 | unsigned long offset; | |
180 | bool is_delete; | |
181 | int i, ret; | |
182 | ||
183 | inode = NULL; | |
184 | ret = 0; | |
185 | is_delete = false; | |
186 | event = NULL; | |
187 | group = NULL; | |
188 | ||
189 | /* argc must be >= 1 */ | |
190 | if (argv[0][0] == '-') | |
191 | is_delete = true; | |
192 | else if (argv[0][0] != 'p') { | |
0d13ac96 | 193 | pr_info("Probe definition must be started with 'p' or '-'.\n"); |
f3f096cf SD |
194 | return -EINVAL; |
195 | } | |
196 | ||
197 | if (argv[0][1] == ':') { | |
198 | event = &argv[0][2]; | |
199 | arg = strchr(event, '/'); | |
200 | ||
201 | if (arg) { | |
202 | group = event; | |
203 | event = arg + 1; | |
204 | event[-1] = '\0'; | |
205 | ||
206 | if (strlen(group) == 0) { | |
207 | pr_info("Group name is not specified\n"); | |
208 | return -EINVAL; | |
209 | } | |
210 | } | |
211 | if (strlen(event) == 0) { | |
212 | pr_info("Event name is not specified\n"); | |
213 | return -EINVAL; | |
214 | } | |
215 | } | |
216 | if (!group) | |
217 | group = UPROBE_EVENT_SYSTEM; | |
218 | ||
219 | if (is_delete) { | |
220 | if (!event) { | |
221 | pr_info("Delete command needs an event name.\n"); | |
222 | return -EINVAL; | |
223 | } | |
224 | mutex_lock(&uprobe_lock); | |
225 | tu = find_probe_event(event, group); | |
226 | ||
227 | if (!tu) { | |
228 | mutex_unlock(&uprobe_lock); | |
229 | pr_info("Event %s/%s doesn't exist.\n", group, event); | |
230 | return -ENOENT; | |
231 | } | |
232 | /* delete an event */ | |
233 | unregister_trace_uprobe(tu); | |
234 | mutex_unlock(&uprobe_lock); | |
235 | return 0; | |
236 | } | |
237 | ||
238 | if (argc < 2) { | |
239 | pr_info("Probe point is not specified.\n"); | |
240 | return -EINVAL; | |
241 | } | |
242 | if (isdigit(argv[1][0])) { | |
243 | pr_info("probe point must be have a filename.\n"); | |
244 | return -EINVAL; | |
245 | } | |
246 | arg = strchr(argv[1], ':'); | |
247 | if (!arg) | |
248 | goto fail_address_parse; | |
249 | ||
250 | *arg++ = '\0'; | |
251 | filename = argv[1]; | |
252 | ret = kern_path(filename, LOOKUP_FOLLOW, &path); | |
253 | if (ret) | |
254 | goto fail_address_parse; | |
255 | ||
f3f096cf | 256 | inode = igrab(path.dentry->d_inode); |
84d7ed79 ON |
257 | path_put(&path); |
258 | ||
d24d7dbf JZ |
259 | if (!S_ISREG(inode->i_mode)) { |
260 | ret = -EINVAL; | |
261 | goto fail_address_parse; | |
262 | } | |
f3f096cf | 263 | |
84d7ed79 ON |
264 | ret = kstrtoul(arg, 0, &offset); |
265 | if (ret) | |
266 | goto fail_address_parse; | |
267 | ||
f3f096cf SD |
268 | argc -= 2; |
269 | argv += 2; | |
270 | ||
271 | /* setup a probe */ | |
272 | if (!event) { | |
b2e902f0 | 273 | char *tail; |
f3f096cf SD |
274 | char *ptr; |
275 | ||
b2e902f0 AS |
276 | tail = kstrdup(kbasename(filename), GFP_KERNEL); |
277 | if (!tail) { | |
f3f096cf SD |
278 | ret = -ENOMEM; |
279 | goto fail_address_parse; | |
280 | } | |
281 | ||
f3f096cf SD |
282 | ptr = strpbrk(tail, ".-_"); |
283 | if (ptr) | |
284 | *ptr = '\0'; | |
285 | ||
286 | snprintf(buf, MAX_EVENT_NAME_LEN, "%c_%s_0x%lx", 'p', tail, offset); | |
287 | event = buf; | |
288 | kfree(tail); | |
289 | } | |
290 | ||
291 | tu = alloc_trace_uprobe(group, event, argc); | |
292 | if (IS_ERR(tu)) { | |
293 | pr_info("Failed to allocate trace_uprobe.(%d)\n", (int)PTR_ERR(tu)); | |
294 | ret = PTR_ERR(tu); | |
295 | goto fail_address_parse; | |
296 | } | |
297 | tu->offset = offset; | |
298 | tu->inode = inode; | |
299 | tu->filename = kstrdup(filename, GFP_KERNEL); | |
300 | ||
301 | if (!tu->filename) { | |
302 | pr_info("Failed to allocate filename.\n"); | |
303 | ret = -ENOMEM; | |
304 | goto error; | |
305 | } | |
306 | ||
307 | /* parse arguments */ | |
308 | ret = 0; | |
309 | for (i = 0; i < argc && i < MAX_TRACE_ARGS; i++) { | |
310 | /* Increment count for freeing args in error case */ | |
311 | tu->nr_args++; | |
312 | ||
313 | /* Parse argument name */ | |
314 | arg = strchr(argv[i], '='); | |
315 | if (arg) { | |
316 | *arg++ = '\0'; | |
317 | tu->args[i].name = kstrdup(argv[i], GFP_KERNEL); | |
318 | } else { | |
319 | arg = argv[i]; | |
320 | /* If argument name is omitted, set "argN" */ | |
321 | snprintf(buf, MAX_EVENT_NAME_LEN, "arg%d", i + 1); | |
322 | tu->args[i].name = kstrdup(buf, GFP_KERNEL); | |
323 | } | |
324 | ||
325 | if (!tu->args[i].name) { | |
326 | pr_info("Failed to allocate argument[%d] name.\n", i); | |
327 | ret = -ENOMEM; | |
328 | goto error; | |
329 | } | |
330 | ||
331 | if (!is_good_name(tu->args[i].name)) { | |
332 | pr_info("Invalid argument[%d] name: %s\n", i, tu->args[i].name); | |
333 | ret = -EINVAL; | |
334 | goto error; | |
335 | } | |
336 | ||
337 | if (traceprobe_conflict_field_name(tu->args[i].name, tu->args, i)) { | |
338 | pr_info("Argument[%d] name '%s' conflicts with " | |
339 | "another field.\n", i, argv[i]); | |
340 | ret = -EINVAL; | |
341 | goto error; | |
342 | } | |
343 | ||
344 | /* Parse fetch argument */ | |
345 | ret = traceprobe_parse_probe_arg(arg, &tu->size, &tu->args[i], false, false); | |
346 | if (ret) { | |
347 | pr_info("Parse error at argument[%d]. (%d)\n", i, ret); | |
348 | goto error; | |
349 | } | |
350 | } | |
351 | ||
352 | ret = register_trace_uprobe(tu); | |
353 | if (ret) | |
354 | goto error; | |
355 | return 0; | |
356 | ||
357 | error: | |
358 | free_trace_uprobe(tu); | |
359 | return ret; | |
360 | ||
361 | fail_address_parse: | |
362 | if (inode) | |
363 | iput(inode); | |
364 | ||
d24d7dbf | 365 | pr_info("Failed to parse address or file.\n"); |
f3f096cf SD |
366 | |
367 | return ret; | |
368 | } | |
369 | ||
370 | static void cleanup_all_probes(void) | |
371 | { | |
372 | struct trace_uprobe *tu; | |
373 | ||
374 | mutex_lock(&uprobe_lock); | |
375 | while (!list_empty(&uprobe_list)) { | |
376 | tu = list_entry(uprobe_list.next, struct trace_uprobe, list); | |
377 | unregister_trace_uprobe(tu); | |
378 | } | |
379 | mutex_unlock(&uprobe_lock); | |
380 | } | |
381 | ||
382 | /* Probes listing interfaces */ | |
383 | static void *probes_seq_start(struct seq_file *m, loff_t *pos) | |
384 | { | |
385 | mutex_lock(&uprobe_lock); | |
386 | return seq_list_start(&uprobe_list, *pos); | |
387 | } | |
388 | ||
389 | static void *probes_seq_next(struct seq_file *m, void *v, loff_t *pos) | |
390 | { | |
391 | return seq_list_next(v, &uprobe_list, pos); | |
392 | } | |
393 | ||
394 | static void probes_seq_stop(struct seq_file *m, void *v) | |
395 | { | |
396 | mutex_unlock(&uprobe_lock); | |
397 | } | |
398 | ||
399 | static int probes_seq_show(struct seq_file *m, void *v) | |
400 | { | |
401 | struct trace_uprobe *tu = v; | |
402 | int i; | |
403 | ||
404 | seq_printf(m, "p:%s/%s", tu->call.class->system, tu->call.name); | |
405 | seq_printf(m, " %s:0x%p", tu->filename, (void *)tu->offset); | |
406 | ||
407 | for (i = 0; i < tu->nr_args; i++) | |
408 | seq_printf(m, " %s=%s", tu->args[i].name, tu->args[i].comm); | |
409 | ||
410 | seq_printf(m, "\n"); | |
411 | return 0; | |
412 | } | |
413 | ||
414 | static const struct seq_operations probes_seq_op = { | |
415 | .start = probes_seq_start, | |
416 | .next = probes_seq_next, | |
417 | .stop = probes_seq_stop, | |
418 | .show = probes_seq_show | |
419 | }; | |
420 | ||
421 | static int probes_open(struct inode *inode, struct file *file) | |
422 | { | |
423 | if ((file->f_mode & FMODE_WRITE) && (file->f_flags & O_TRUNC)) | |
424 | cleanup_all_probes(); | |
425 | ||
426 | return seq_open(file, &probes_seq_op); | |
427 | } | |
428 | ||
429 | static ssize_t probes_write(struct file *file, const char __user *buffer, | |
430 | size_t count, loff_t *ppos) | |
431 | { | |
432 | return traceprobe_probes_write(file, buffer, count, ppos, create_trace_uprobe); | |
433 | } | |
434 | ||
435 | static const struct file_operations uprobe_events_ops = { | |
436 | .owner = THIS_MODULE, | |
437 | .open = probes_open, | |
438 | .read = seq_read, | |
439 | .llseek = seq_lseek, | |
440 | .release = seq_release, | |
441 | .write = probes_write, | |
442 | }; | |
443 | ||
444 | /* Probes profiling interfaces */ | |
445 | static int probes_profile_seq_show(struct seq_file *m, void *v) | |
446 | { | |
447 | struct trace_uprobe *tu = v; | |
448 | ||
449 | seq_printf(m, " %s %-44s %15lu\n", tu->filename, tu->call.name, tu->nhit); | |
450 | return 0; | |
451 | } | |
452 | ||
453 | static const struct seq_operations profile_seq_op = { | |
454 | .start = probes_seq_start, | |
455 | .next = probes_seq_next, | |
456 | .stop = probes_seq_stop, | |
457 | .show = probes_profile_seq_show | |
458 | }; | |
459 | ||
460 | static int profile_open(struct inode *inode, struct file *file) | |
461 | { | |
462 | return seq_open(file, &profile_seq_op); | |
463 | } | |
464 | ||
465 | static const struct file_operations uprobe_profile_ops = { | |
466 | .owner = THIS_MODULE, | |
467 | .open = profile_open, | |
468 | .read = seq_read, | |
469 | .llseek = seq_lseek, | |
470 | .release = seq_release, | |
471 | }; | |
472 | ||
473 | /* uprobe handler */ | |
474 | static void uprobe_trace_func(struct trace_uprobe *tu, struct pt_regs *regs) | |
475 | { | |
476 | struct uprobe_trace_entry_head *entry; | |
477 | struct ring_buffer_event *event; | |
478 | struct ring_buffer *buffer; | |
479 | u8 *data; | |
480 | int size, i, pc; | |
481 | unsigned long irq_flags; | |
482 | struct ftrace_event_call *call = &tu->call; | |
483 | ||
484 | tu->nhit++; | |
485 | ||
486 | local_save_flags(irq_flags); | |
487 | pc = preempt_count(); | |
488 | ||
489 | size = sizeof(*entry) + tu->size; | |
490 | ||
491 | event = trace_current_buffer_lock_reserve(&buffer, call->event.type, | |
492 | size, irq_flags, pc); | |
493 | if (!event) | |
494 | return; | |
495 | ||
496 | entry = ring_buffer_event_data(event); | |
74e59dfc | 497 | entry->ip = instruction_pointer(task_pt_regs(current)); |
f3f096cf SD |
498 | data = (u8 *)&entry[1]; |
499 | for (i = 0; i < tu->nr_args; i++) | |
500 | call_fetch(&tu->args[i].fetch, regs, data + tu->args[i].offset); | |
501 | ||
502 | if (!filter_current_check_discard(buffer, call, entry, event)) | |
503 | trace_buffer_unlock_commit(buffer, event, irq_flags, pc); | |
504 | } | |
505 | ||
506 | /* Event entry printers */ | |
507 | static enum print_line_t | |
508 | print_uprobe_event(struct trace_iterator *iter, int flags, struct trace_event *event) | |
509 | { | |
510 | struct uprobe_trace_entry_head *field; | |
511 | struct trace_seq *s = &iter->seq; | |
512 | struct trace_uprobe *tu; | |
513 | u8 *data; | |
514 | int i; | |
515 | ||
516 | field = (struct uprobe_trace_entry_head *)iter->ent; | |
517 | tu = container_of(event, struct trace_uprobe, call.event); | |
518 | ||
519 | if (!trace_seq_printf(s, "%s: (", tu->call.name)) | |
520 | goto partial; | |
521 | ||
522 | if (!seq_print_ip_sym(s, field->ip, flags | TRACE_ITER_SYM_OFFSET)) | |
523 | goto partial; | |
524 | ||
525 | if (!trace_seq_puts(s, ")")) | |
526 | goto partial; | |
527 | ||
528 | data = (u8 *)&field[1]; | |
529 | for (i = 0; i < tu->nr_args; i++) { | |
530 | if (!tu->args[i].type->print(s, tu->args[i].name, | |
531 | data + tu->args[i].offset, field)) | |
532 | goto partial; | |
533 | } | |
534 | ||
535 | if (trace_seq_puts(s, "\n")) | |
536 | return TRACE_TYPE_HANDLED; | |
537 | ||
538 | partial: | |
539 | return TRACE_TYPE_PARTIAL_LINE; | |
540 | } | |
541 | ||
542 | static int probe_event_enable(struct trace_uprobe *tu, int flag) | |
543 | { | |
544 | struct uprobe_trace_consumer *utc; | |
545 | int ret = 0; | |
546 | ||
547 | if (!tu->inode || tu->consumer) | |
548 | return -EINTR; | |
549 | ||
550 | utc = kzalloc(sizeof(struct uprobe_trace_consumer), GFP_KERNEL); | |
551 | if (!utc) | |
552 | return -EINTR; | |
553 | ||
554 | utc->cons.handler = uprobe_dispatcher; | |
f3f096cf SD |
555 | ret = uprobe_register(tu->inode, tu->offset, &utc->cons); |
556 | if (ret) { | |
557 | kfree(utc); | |
558 | return ret; | |
559 | } | |
560 | ||
561 | tu->flags |= flag; | |
562 | utc->tu = tu; | |
563 | tu->consumer = utc; | |
564 | ||
565 | return 0; | |
566 | } | |
567 | ||
568 | static void probe_event_disable(struct trace_uprobe *tu, int flag) | |
569 | { | |
570 | if (!tu->inode || !tu->consumer) | |
571 | return; | |
572 | ||
573 | uprobe_unregister(tu->inode, tu->offset, &tu->consumer->cons); | |
574 | tu->flags &= ~flag; | |
575 | kfree(tu->consumer); | |
576 | tu->consumer = NULL; | |
577 | } | |
578 | ||
579 | static int uprobe_event_define_fields(struct ftrace_event_call *event_call) | |
580 | { | |
581 | int ret, i; | |
582 | struct uprobe_trace_entry_head field; | |
583 | struct trace_uprobe *tu = (struct trace_uprobe *)event_call->data; | |
584 | ||
585 | DEFINE_FIELD(unsigned long, ip, FIELD_STRING_IP, 0); | |
586 | /* Set argument names as fields */ | |
587 | for (i = 0; i < tu->nr_args; i++) { | |
588 | ret = trace_define_field(event_call, tu->args[i].type->fmttype, | |
589 | tu->args[i].name, | |
590 | sizeof(field) + tu->args[i].offset, | |
591 | tu->args[i].type->size, | |
592 | tu->args[i].type->is_signed, | |
593 | FILTER_OTHER); | |
594 | ||
595 | if (ret) | |
596 | return ret; | |
597 | } | |
598 | return 0; | |
599 | } | |
600 | ||
601 | #define LEN_OR_ZERO (len ? len - pos : 0) | |
602 | static int __set_print_fmt(struct trace_uprobe *tu, char *buf, int len) | |
603 | { | |
604 | const char *fmt, *arg; | |
605 | int i; | |
606 | int pos = 0; | |
607 | ||
608 | fmt = "(%lx)"; | |
609 | arg = "REC->" FIELD_STRING_IP; | |
610 | ||
611 | /* When len=0, we just calculate the needed length */ | |
612 | ||
613 | pos += snprintf(buf + pos, LEN_OR_ZERO, "\"%s", fmt); | |
614 | ||
615 | for (i = 0; i < tu->nr_args; i++) { | |
616 | pos += snprintf(buf + pos, LEN_OR_ZERO, " %s=%s", | |
617 | tu->args[i].name, tu->args[i].type->fmt); | |
618 | } | |
619 | ||
620 | pos += snprintf(buf + pos, LEN_OR_ZERO, "\", %s", arg); | |
621 | ||
622 | for (i = 0; i < tu->nr_args; i++) { | |
623 | pos += snprintf(buf + pos, LEN_OR_ZERO, ", REC->%s", | |
624 | tu->args[i].name); | |
625 | } | |
626 | ||
627 | return pos; /* return the length of print_fmt */ | |
628 | } | |
629 | #undef LEN_OR_ZERO | |
630 | ||
631 | static int set_print_fmt(struct trace_uprobe *tu) | |
632 | { | |
633 | char *print_fmt; | |
634 | int len; | |
635 | ||
636 | /* First: called with 0 length to calculate the needed length */ | |
637 | len = __set_print_fmt(tu, NULL, 0); | |
638 | print_fmt = kmalloc(len + 1, GFP_KERNEL); | |
639 | if (!print_fmt) | |
640 | return -ENOMEM; | |
641 | ||
642 | /* Second: actually write the @print_fmt */ | |
643 | __set_print_fmt(tu, print_fmt, len + 1); | |
644 | tu->call.print_fmt = print_fmt; | |
645 | ||
646 | return 0; | |
647 | } | |
648 | ||
649 | #ifdef CONFIG_PERF_EVENTS | |
650 | /* uprobe profile handler */ | |
651 | static void uprobe_perf_func(struct trace_uprobe *tu, struct pt_regs *regs) | |
652 | { | |
653 | struct ftrace_event_call *call = &tu->call; | |
654 | struct uprobe_trace_entry_head *entry; | |
655 | struct hlist_head *head; | |
656 | u8 *data; | |
657 | int size, __size, i; | |
658 | int rctx; | |
659 | ||
660 | __size = sizeof(*entry) + tu->size; | |
661 | size = ALIGN(__size + sizeof(u32), sizeof(u64)); | |
662 | size -= sizeof(u32); | |
663 | if (WARN_ONCE(size > PERF_MAX_TRACE_SIZE, "profile buffer not large enough")) | |
664 | return; | |
665 | ||
666 | preempt_disable(); | |
667 | ||
668 | entry = perf_trace_buf_prepare(size, call->event.type, regs, &rctx); | |
669 | if (!entry) | |
670 | goto out; | |
671 | ||
74e59dfc | 672 | entry->ip = instruction_pointer(task_pt_regs(current)); |
f3f096cf SD |
673 | data = (u8 *)&entry[1]; |
674 | for (i = 0; i < tu->nr_args; i++) | |
675 | call_fetch(&tu->args[i].fetch, regs, data + tu->args[i].offset); | |
676 | ||
677 | head = this_cpu_ptr(call->perf_events); | |
e6dab5ff | 678 | perf_trace_buf_submit(entry, size, rctx, entry->ip, 1, regs, head, NULL); |
f3f096cf SD |
679 | |
680 | out: | |
681 | preempt_enable(); | |
682 | } | |
683 | #endif /* CONFIG_PERF_EVENTS */ | |
684 | ||
685 | static | |
686 | int trace_uprobe_register(struct ftrace_event_call *event, enum trace_reg type, void *data) | |
687 | { | |
688 | struct trace_uprobe *tu = (struct trace_uprobe *)event->data; | |
689 | ||
690 | switch (type) { | |
691 | case TRACE_REG_REGISTER: | |
692 | return probe_event_enable(tu, TP_FLAG_TRACE); | |
693 | ||
694 | case TRACE_REG_UNREGISTER: | |
695 | probe_event_disable(tu, TP_FLAG_TRACE); | |
696 | return 0; | |
697 | ||
698 | #ifdef CONFIG_PERF_EVENTS | |
699 | case TRACE_REG_PERF_REGISTER: | |
700 | return probe_event_enable(tu, TP_FLAG_PROFILE); | |
701 | ||
702 | case TRACE_REG_PERF_UNREGISTER: | |
703 | probe_event_disable(tu, TP_FLAG_PROFILE); | |
704 | return 0; | |
705 | #endif | |
706 | default: | |
707 | return 0; | |
708 | } | |
709 | return 0; | |
710 | } | |
711 | ||
712 | static int uprobe_dispatcher(struct uprobe_consumer *con, struct pt_regs *regs) | |
713 | { | |
714 | struct uprobe_trace_consumer *utc; | |
715 | struct trace_uprobe *tu; | |
716 | ||
717 | utc = container_of(con, struct uprobe_trace_consumer, cons); | |
718 | tu = utc->tu; | |
719 | if (!tu || tu->consumer != utc) | |
720 | return 0; | |
721 | ||
722 | if (tu->flags & TP_FLAG_TRACE) | |
723 | uprobe_trace_func(tu, regs); | |
724 | ||
725 | #ifdef CONFIG_PERF_EVENTS | |
726 | if (tu->flags & TP_FLAG_PROFILE) | |
727 | uprobe_perf_func(tu, regs); | |
728 | #endif | |
729 | return 0; | |
730 | } | |
731 | ||
732 | static struct trace_event_functions uprobe_funcs = { | |
733 | .trace = print_uprobe_event | |
734 | }; | |
735 | ||
736 | static int register_uprobe_event(struct trace_uprobe *tu) | |
737 | { | |
738 | struct ftrace_event_call *call = &tu->call; | |
739 | int ret; | |
740 | ||
741 | /* Initialize ftrace_event_call */ | |
742 | INIT_LIST_HEAD(&call->class->fields); | |
743 | call->event.funcs = &uprobe_funcs; | |
744 | call->class->define_fields = uprobe_event_define_fields; | |
745 | ||
746 | if (set_print_fmt(tu) < 0) | |
747 | return -ENOMEM; | |
748 | ||
749 | ret = register_ftrace_event(&call->event); | |
750 | if (!ret) { | |
751 | kfree(call->print_fmt); | |
752 | return -ENODEV; | |
753 | } | |
754 | call->flags = 0; | |
755 | call->class->reg = trace_uprobe_register; | |
756 | call->data = tu; | |
757 | ret = trace_add_event_call(call); | |
758 | ||
759 | if (ret) { | |
760 | pr_info("Failed to register uprobe event: %s\n", call->name); | |
761 | kfree(call->print_fmt); | |
762 | unregister_ftrace_event(&call->event); | |
763 | } | |
764 | ||
765 | return ret; | |
766 | } | |
767 | ||
768 | static void unregister_uprobe_event(struct trace_uprobe *tu) | |
769 | { | |
770 | /* tu->event is unregistered in trace_remove_event_call() */ | |
771 | trace_remove_event_call(&tu->call); | |
772 | kfree(tu->call.print_fmt); | |
773 | tu->call.print_fmt = NULL; | |
774 | } | |
775 | ||
776 | /* Make a trace interface for controling probe points */ | |
777 | static __init int init_uprobe_trace(void) | |
778 | { | |
779 | struct dentry *d_tracer; | |
780 | ||
781 | d_tracer = tracing_init_dentry(); | |
782 | if (!d_tracer) | |
783 | return 0; | |
784 | ||
785 | trace_create_file("uprobe_events", 0644, d_tracer, | |
786 | NULL, &uprobe_events_ops); | |
787 | /* Profile interface */ | |
788 | trace_create_file("uprobe_profile", 0444, d_tracer, | |
789 | NULL, &uprobe_profile_ops); | |
790 | return 0; | |
791 | } | |
792 | ||
793 | fs_initcall(init_uprobe_trace); |