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Commit | Line | Data |
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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 | ||
736288ba ON |
31 | struct trace_uprobe_filter { |
32 | rwlock_t rwlock; | |
33 | int nr_systemwide; | |
34 | struct list_head perf_events; | |
35 | }; | |
36 | ||
f3f096cf SD |
37 | /* |
38 | * uprobe event core functions | |
39 | */ | |
f3f096cf SD |
40 | struct trace_uprobe { |
41 | struct list_head list; | |
42 | struct ftrace_event_class class; | |
43 | struct ftrace_event_call call; | |
736288ba | 44 | struct trace_uprobe_filter filter; |
a932b738 | 45 | struct uprobe_consumer consumer; |
f3f096cf SD |
46 | struct inode *inode; |
47 | char *filename; | |
48 | unsigned long offset; | |
49 | unsigned long nhit; | |
50 | unsigned int flags; /* For TP_FLAG_* */ | |
51 | ssize_t size; /* trace entry size */ | |
52 | unsigned int nr_args; | |
53 | struct probe_arg args[]; | |
54 | }; | |
55 | ||
56 | #define SIZEOF_TRACE_UPROBE(n) \ | |
57 | (offsetof(struct trace_uprobe, args) + \ | |
58 | (sizeof(struct probe_arg) * (n))) | |
59 | ||
60 | static int register_uprobe_event(struct trace_uprobe *tu); | |
61 | static void unregister_uprobe_event(struct trace_uprobe *tu); | |
62 | ||
63 | static DEFINE_MUTEX(uprobe_lock); | |
64 | static LIST_HEAD(uprobe_list); | |
65 | ||
66 | static int uprobe_dispatcher(struct uprobe_consumer *con, struct pt_regs *regs); | |
67 | ||
736288ba ON |
68 | static inline void init_trace_uprobe_filter(struct trace_uprobe_filter *filter) |
69 | { | |
70 | rwlock_init(&filter->rwlock); | |
71 | filter->nr_systemwide = 0; | |
72 | INIT_LIST_HEAD(&filter->perf_events); | |
73 | } | |
74 | ||
75 | static inline bool uprobe_filter_is_empty(struct trace_uprobe_filter *filter) | |
76 | { | |
77 | return !filter->nr_systemwide && list_empty(&filter->perf_events); | |
78 | } | |
79 | ||
f3f096cf SD |
80 | /* |
81 | * Allocate new trace_uprobe and initialize it (including uprobes). | |
82 | */ | |
83 | static struct trace_uprobe * | |
84 | alloc_trace_uprobe(const char *group, const char *event, int nargs) | |
85 | { | |
86 | struct trace_uprobe *tu; | |
87 | ||
88 | if (!event || !is_good_name(event)) | |
89 | return ERR_PTR(-EINVAL); | |
90 | ||
91 | if (!group || !is_good_name(group)) | |
92 | return ERR_PTR(-EINVAL); | |
93 | ||
94 | tu = kzalloc(SIZEOF_TRACE_UPROBE(nargs), GFP_KERNEL); | |
95 | if (!tu) | |
96 | return ERR_PTR(-ENOMEM); | |
97 | ||
98 | tu->call.class = &tu->class; | |
99 | tu->call.name = kstrdup(event, GFP_KERNEL); | |
100 | if (!tu->call.name) | |
101 | goto error; | |
102 | ||
103 | tu->class.system = kstrdup(group, GFP_KERNEL); | |
104 | if (!tu->class.system) | |
105 | goto error; | |
106 | ||
107 | INIT_LIST_HEAD(&tu->list); | |
a932b738 | 108 | tu->consumer.handler = uprobe_dispatcher; |
736288ba | 109 | init_trace_uprobe_filter(&tu->filter); |
f3f096cf SD |
110 | return tu; |
111 | ||
112 | error: | |
113 | kfree(tu->call.name); | |
114 | kfree(tu); | |
115 | ||
116 | return ERR_PTR(-ENOMEM); | |
117 | } | |
118 | ||
119 | static void free_trace_uprobe(struct trace_uprobe *tu) | |
120 | { | |
121 | int i; | |
122 | ||
123 | for (i = 0; i < tu->nr_args; i++) | |
124 | traceprobe_free_probe_arg(&tu->args[i]); | |
125 | ||
126 | iput(tu->inode); | |
127 | kfree(tu->call.class->system); | |
128 | kfree(tu->call.name); | |
129 | kfree(tu->filename); | |
130 | kfree(tu); | |
131 | } | |
132 | ||
133 | static struct trace_uprobe *find_probe_event(const char *event, const char *group) | |
134 | { | |
135 | struct trace_uprobe *tu; | |
136 | ||
137 | list_for_each_entry(tu, &uprobe_list, list) | |
138 | if (strcmp(tu->call.name, event) == 0 && | |
139 | strcmp(tu->call.class->system, group) == 0) | |
140 | return tu; | |
141 | ||
142 | return NULL; | |
143 | } | |
144 | ||
145 | /* Unregister a trace_uprobe and probe_event: call with locking uprobe_lock */ | |
146 | static void unregister_trace_uprobe(struct trace_uprobe *tu) | |
147 | { | |
148 | list_del(&tu->list); | |
149 | unregister_uprobe_event(tu); | |
150 | free_trace_uprobe(tu); | |
151 | } | |
152 | ||
153 | /* Register a trace_uprobe and probe_event */ | |
154 | static int register_trace_uprobe(struct trace_uprobe *tu) | |
155 | { | |
156 | struct trace_uprobe *old_tp; | |
157 | int ret; | |
158 | ||
159 | mutex_lock(&uprobe_lock); | |
160 | ||
161 | /* register as an event */ | |
162 | old_tp = find_probe_event(tu->call.name, tu->call.class->system); | |
163 | if (old_tp) | |
164 | /* delete old event */ | |
165 | unregister_trace_uprobe(old_tp); | |
166 | ||
167 | ret = register_uprobe_event(tu); | |
168 | if (ret) { | |
169 | pr_warning("Failed to register probe event(%d)\n", ret); | |
170 | goto end; | |
171 | } | |
172 | ||
173 | list_add_tail(&tu->list, &uprobe_list); | |
174 | ||
175 | end: | |
176 | mutex_unlock(&uprobe_lock); | |
177 | ||
178 | return ret; | |
179 | } | |
180 | ||
181 | /* | |
182 | * Argument syntax: | |
183 | * - Add uprobe: p[:[GRP/]EVENT] PATH:SYMBOL[+offs] [FETCHARGS] | |
184 | * | |
185 | * - Remove uprobe: -:[GRP/]EVENT | |
186 | */ | |
187 | static int create_trace_uprobe(int argc, char **argv) | |
188 | { | |
189 | struct trace_uprobe *tu; | |
190 | struct inode *inode; | |
191 | char *arg, *event, *group, *filename; | |
192 | char buf[MAX_EVENT_NAME_LEN]; | |
193 | struct path path; | |
194 | unsigned long offset; | |
195 | bool is_delete; | |
196 | int i, ret; | |
197 | ||
198 | inode = NULL; | |
199 | ret = 0; | |
200 | is_delete = false; | |
201 | event = NULL; | |
202 | group = NULL; | |
203 | ||
204 | /* argc must be >= 1 */ | |
205 | if (argv[0][0] == '-') | |
206 | is_delete = true; | |
207 | else if (argv[0][0] != 'p') { | |
0d13ac96 | 208 | pr_info("Probe definition must be started with 'p' or '-'.\n"); |
f3f096cf SD |
209 | return -EINVAL; |
210 | } | |
211 | ||
212 | if (argv[0][1] == ':') { | |
213 | event = &argv[0][2]; | |
214 | arg = strchr(event, '/'); | |
215 | ||
216 | if (arg) { | |
217 | group = event; | |
218 | event = arg + 1; | |
219 | event[-1] = '\0'; | |
220 | ||
221 | if (strlen(group) == 0) { | |
222 | pr_info("Group name is not specified\n"); | |
223 | return -EINVAL; | |
224 | } | |
225 | } | |
226 | if (strlen(event) == 0) { | |
227 | pr_info("Event name is not specified\n"); | |
228 | return -EINVAL; | |
229 | } | |
230 | } | |
231 | if (!group) | |
232 | group = UPROBE_EVENT_SYSTEM; | |
233 | ||
234 | if (is_delete) { | |
235 | if (!event) { | |
236 | pr_info("Delete command needs an event name.\n"); | |
237 | return -EINVAL; | |
238 | } | |
239 | mutex_lock(&uprobe_lock); | |
240 | tu = find_probe_event(event, group); | |
241 | ||
242 | if (!tu) { | |
243 | mutex_unlock(&uprobe_lock); | |
244 | pr_info("Event %s/%s doesn't exist.\n", group, event); | |
245 | return -ENOENT; | |
246 | } | |
247 | /* delete an event */ | |
248 | unregister_trace_uprobe(tu); | |
249 | mutex_unlock(&uprobe_lock); | |
250 | return 0; | |
251 | } | |
252 | ||
253 | if (argc < 2) { | |
254 | pr_info("Probe point is not specified.\n"); | |
255 | return -EINVAL; | |
256 | } | |
257 | if (isdigit(argv[1][0])) { | |
258 | pr_info("probe point must be have a filename.\n"); | |
259 | return -EINVAL; | |
260 | } | |
261 | arg = strchr(argv[1], ':'); | |
262 | if (!arg) | |
263 | goto fail_address_parse; | |
264 | ||
265 | *arg++ = '\0'; | |
266 | filename = argv[1]; | |
267 | ret = kern_path(filename, LOOKUP_FOLLOW, &path); | |
268 | if (ret) | |
269 | goto fail_address_parse; | |
270 | ||
f3f096cf | 271 | inode = igrab(path.dentry->d_inode); |
84d7ed79 ON |
272 | path_put(&path); |
273 | ||
7e4e28c5 | 274 | if (!inode || !S_ISREG(inode->i_mode)) { |
d24d7dbf JZ |
275 | ret = -EINVAL; |
276 | goto fail_address_parse; | |
277 | } | |
f3f096cf | 278 | |
84d7ed79 ON |
279 | ret = kstrtoul(arg, 0, &offset); |
280 | if (ret) | |
281 | goto fail_address_parse; | |
282 | ||
f3f096cf SD |
283 | argc -= 2; |
284 | argv += 2; | |
285 | ||
286 | /* setup a probe */ | |
287 | if (!event) { | |
b2e902f0 | 288 | char *tail; |
f3f096cf SD |
289 | char *ptr; |
290 | ||
b2e902f0 AS |
291 | tail = kstrdup(kbasename(filename), GFP_KERNEL); |
292 | if (!tail) { | |
f3f096cf SD |
293 | ret = -ENOMEM; |
294 | goto fail_address_parse; | |
295 | } | |
296 | ||
f3f096cf SD |
297 | ptr = strpbrk(tail, ".-_"); |
298 | if (ptr) | |
299 | *ptr = '\0'; | |
300 | ||
301 | snprintf(buf, MAX_EVENT_NAME_LEN, "%c_%s_0x%lx", 'p', tail, offset); | |
302 | event = buf; | |
303 | kfree(tail); | |
304 | } | |
305 | ||
306 | tu = alloc_trace_uprobe(group, event, argc); | |
307 | if (IS_ERR(tu)) { | |
308 | pr_info("Failed to allocate trace_uprobe.(%d)\n", (int)PTR_ERR(tu)); | |
309 | ret = PTR_ERR(tu); | |
310 | goto fail_address_parse; | |
311 | } | |
312 | tu->offset = offset; | |
313 | tu->inode = inode; | |
314 | tu->filename = kstrdup(filename, GFP_KERNEL); | |
315 | ||
316 | if (!tu->filename) { | |
317 | pr_info("Failed to allocate filename.\n"); | |
318 | ret = -ENOMEM; | |
319 | goto error; | |
320 | } | |
321 | ||
322 | /* parse arguments */ | |
323 | ret = 0; | |
324 | for (i = 0; i < argc && i < MAX_TRACE_ARGS; i++) { | |
325 | /* Increment count for freeing args in error case */ | |
326 | tu->nr_args++; | |
327 | ||
328 | /* Parse argument name */ | |
329 | arg = strchr(argv[i], '='); | |
330 | if (arg) { | |
331 | *arg++ = '\0'; | |
332 | tu->args[i].name = kstrdup(argv[i], GFP_KERNEL); | |
333 | } else { | |
334 | arg = argv[i]; | |
335 | /* If argument name is omitted, set "argN" */ | |
336 | snprintf(buf, MAX_EVENT_NAME_LEN, "arg%d", i + 1); | |
337 | tu->args[i].name = kstrdup(buf, GFP_KERNEL); | |
338 | } | |
339 | ||
340 | if (!tu->args[i].name) { | |
341 | pr_info("Failed to allocate argument[%d] name.\n", i); | |
342 | ret = -ENOMEM; | |
343 | goto error; | |
344 | } | |
345 | ||
346 | if (!is_good_name(tu->args[i].name)) { | |
347 | pr_info("Invalid argument[%d] name: %s\n", i, tu->args[i].name); | |
348 | ret = -EINVAL; | |
349 | goto error; | |
350 | } | |
351 | ||
352 | if (traceprobe_conflict_field_name(tu->args[i].name, tu->args, i)) { | |
353 | pr_info("Argument[%d] name '%s' conflicts with " | |
354 | "another field.\n", i, argv[i]); | |
355 | ret = -EINVAL; | |
356 | goto error; | |
357 | } | |
358 | ||
359 | /* Parse fetch argument */ | |
360 | ret = traceprobe_parse_probe_arg(arg, &tu->size, &tu->args[i], false, false); | |
361 | if (ret) { | |
362 | pr_info("Parse error at argument[%d]. (%d)\n", i, ret); | |
363 | goto error; | |
364 | } | |
365 | } | |
366 | ||
367 | ret = register_trace_uprobe(tu); | |
368 | if (ret) | |
369 | goto error; | |
370 | return 0; | |
371 | ||
372 | error: | |
373 | free_trace_uprobe(tu); | |
374 | return ret; | |
375 | ||
376 | fail_address_parse: | |
377 | if (inode) | |
378 | iput(inode); | |
379 | ||
d24d7dbf | 380 | pr_info("Failed to parse address or file.\n"); |
f3f096cf SD |
381 | |
382 | return ret; | |
383 | } | |
384 | ||
385 | static void cleanup_all_probes(void) | |
386 | { | |
387 | struct trace_uprobe *tu; | |
388 | ||
389 | mutex_lock(&uprobe_lock); | |
390 | while (!list_empty(&uprobe_list)) { | |
391 | tu = list_entry(uprobe_list.next, struct trace_uprobe, list); | |
392 | unregister_trace_uprobe(tu); | |
393 | } | |
394 | mutex_unlock(&uprobe_lock); | |
395 | } | |
396 | ||
397 | /* Probes listing interfaces */ | |
398 | static void *probes_seq_start(struct seq_file *m, loff_t *pos) | |
399 | { | |
400 | mutex_lock(&uprobe_lock); | |
401 | return seq_list_start(&uprobe_list, *pos); | |
402 | } | |
403 | ||
404 | static void *probes_seq_next(struct seq_file *m, void *v, loff_t *pos) | |
405 | { | |
406 | return seq_list_next(v, &uprobe_list, pos); | |
407 | } | |
408 | ||
409 | static void probes_seq_stop(struct seq_file *m, void *v) | |
410 | { | |
411 | mutex_unlock(&uprobe_lock); | |
412 | } | |
413 | ||
414 | static int probes_seq_show(struct seq_file *m, void *v) | |
415 | { | |
416 | struct trace_uprobe *tu = v; | |
417 | int i; | |
418 | ||
419 | seq_printf(m, "p:%s/%s", tu->call.class->system, tu->call.name); | |
420 | seq_printf(m, " %s:0x%p", tu->filename, (void *)tu->offset); | |
421 | ||
422 | for (i = 0; i < tu->nr_args; i++) | |
423 | seq_printf(m, " %s=%s", tu->args[i].name, tu->args[i].comm); | |
424 | ||
425 | seq_printf(m, "\n"); | |
426 | return 0; | |
427 | } | |
428 | ||
429 | static const struct seq_operations probes_seq_op = { | |
430 | .start = probes_seq_start, | |
431 | .next = probes_seq_next, | |
432 | .stop = probes_seq_stop, | |
433 | .show = probes_seq_show | |
434 | }; | |
435 | ||
436 | static int probes_open(struct inode *inode, struct file *file) | |
437 | { | |
438 | if ((file->f_mode & FMODE_WRITE) && (file->f_flags & O_TRUNC)) | |
439 | cleanup_all_probes(); | |
440 | ||
441 | return seq_open(file, &probes_seq_op); | |
442 | } | |
443 | ||
444 | static ssize_t probes_write(struct file *file, const char __user *buffer, | |
445 | size_t count, loff_t *ppos) | |
446 | { | |
447 | return traceprobe_probes_write(file, buffer, count, ppos, create_trace_uprobe); | |
448 | } | |
449 | ||
450 | static const struct file_operations uprobe_events_ops = { | |
451 | .owner = THIS_MODULE, | |
452 | .open = probes_open, | |
453 | .read = seq_read, | |
454 | .llseek = seq_lseek, | |
455 | .release = seq_release, | |
456 | .write = probes_write, | |
457 | }; | |
458 | ||
459 | /* Probes profiling interfaces */ | |
460 | static int probes_profile_seq_show(struct seq_file *m, void *v) | |
461 | { | |
462 | struct trace_uprobe *tu = v; | |
463 | ||
464 | seq_printf(m, " %s %-44s %15lu\n", tu->filename, tu->call.name, tu->nhit); | |
465 | return 0; | |
466 | } | |
467 | ||
468 | static const struct seq_operations profile_seq_op = { | |
469 | .start = probes_seq_start, | |
470 | .next = probes_seq_next, | |
471 | .stop = probes_seq_stop, | |
472 | .show = probes_profile_seq_show | |
473 | }; | |
474 | ||
475 | static int profile_open(struct inode *inode, struct file *file) | |
476 | { | |
477 | return seq_open(file, &profile_seq_op); | |
478 | } | |
479 | ||
480 | static const struct file_operations uprobe_profile_ops = { | |
481 | .owner = THIS_MODULE, | |
482 | .open = profile_open, | |
483 | .read = seq_read, | |
484 | .llseek = seq_lseek, | |
485 | .release = seq_release, | |
486 | }; | |
487 | ||
488 | /* uprobe handler */ | |
489 | static void uprobe_trace_func(struct trace_uprobe *tu, struct pt_regs *regs) | |
490 | { | |
491 | struct uprobe_trace_entry_head *entry; | |
492 | struct ring_buffer_event *event; | |
493 | struct ring_buffer *buffer; | |
494 | u8 *data; | |
495 | int size, i, pc; | |
496 | unsigned long irq_flags; | |
497 | struct ftrace_event_call *call = &tu->call; | |
498 | ||
f3f096cf SD |
499 | local_save_flags(irq_flags); |
500 | pc = preempt_count(); | |
501 | ||
502 | size = sizeof(*entry) + tu->size; | |
503 | ||
504 | event = trace_current_buffer_lock_reserve(&buffer, call->event.type, | |
505 | size, irq_flags, pc); | |
506 | if (!event) | |
507 | return; | |
508 | ||
509 | entry = ring_buffer_event_data(event); | |
74e59dfc | 510 | entry->ip = instruction_pointer(task_pt_regs(current)); |
f3f096cf SD |
511 | data = (u8 *)&entry[1]; |
512 | for (i = 0; i < tu->nr_args; i++) | |
513 | call_fetch(&tu->args[i].fetch, regs, data + tu->args[i].offset); | |
514 | ||
515 | if (!filter_current_check_discard(buffer, call, entry, event)) | |
516 | trace_buffer_unlock_commit(buffer, event, irq_flags, pc); | |
517 | } | |
518 | ||
519 | /* Event entry printers */ | |
520 | static enum print_line_t | |
521 | print_uprobe_event(struct trace_iterator *iter, int flags, struct trace_event *event) | |
522 | { | |
523 | struct uprobe_trace_entry_head *field; | |
524 | struct trace_seq *s = &iter->seq; | |
525 | struct trace_uprobe *tu; | |
526 | u8 *data; | |
527 | int i; | |
528 | ||
529 | field = (struct uprobe_trace_entry_head *)iter->ent; | |
530 | tu = container_of(event, struct trace_uprobe, call.event); | |
531 | ||
532 | if (!trace_seq_printf(s, "%s: (", tu->call.name)) | |
533 | goto partial; | |
534 | ||
535 | if (!seq_print_ip_sym(s, field->ip, flags | TRACE_ITER_SYM_OFFSET)) | |
536 | goto partial; | |
537 | ||
538 | if (!trace_seq_puts(s, ")")) | |
539 | goto partial; | |
540 | ||
541 | data = (u8 *)&field[1]; | |
542 | for (i = 0; i < tu->nr_args; i++) { | |
543 | if (!tu->args[i].type->print(s, tu->args[i].name, | |
544 | data + tu->args[i].offset, field)) | |
545 | goto partial; | |
546 | } | |
547 | ||
548 | if (trace_seq_puts(s, "\n")) | |
549 | return TRACE_TYPE_HANDLED; | |
550 | ||
551 | partial: | |
552 | return TRACE_TYPE_PARTIAL_LINE; | |
553 | } | |
554 | ||
b64b0077 ON |
555 | static inline bool is_trace_uprobe_enabled(struct trace_uprobe *tu) |
556 | { | |
557 | return tu->flags & (TP_FLAG_TRACE | TP_FLAG_PROFILE); | |
558 | } | |
559 | ||
31ba3348 ON |
560 | typedef bool (*filter_func_t)(struct uprobe_consumer *self, |
561 | enum uprobe_filter_ctx ctx, | |
562 | struct mm_struct *mm); | |
563 | ||
564 | static int | |
565 | probe_event_enable(struct trace_uprobe *tu, int flag, filter_func_t filter) | |
f3f096cf | 566 | { |
f3f096cf SD |
567 | int ret = 0; |
568 | ||
b64b0077 | 569 | if (is_trace_uprobe_enabled(tu)) |
f3f096cf SD |
570 | return -EINTR; |
571 | ||
736288ba ON |
572 | WARN_ON(!uprobe_filter_is_empty(&tu->filter)); |
573 | ||
4161824f | 574 | tu->flags |= flag; |
31ba3348 | 575 | tu->consumer.filter = filter; |
a932b738 ON |
576 | ret = uprobe_register(tu->inode, tu->offset, &tu->consumer); |
577 | if (ret) | |
4161824f | 578 | tu->flags &= ~flag; |
f3f096cf | 579 | |
4161824f | 580 | return ret; |
f3f096cf SD |
581 | } |
582 | ||
583 | static void probe_event_disable(struct trace_uprobe *tu, int flag) | |
584 | { | |
b64b0077 | 585 | if (!is_trace_uprobe_enabled(tu)) |
f3f096cf SD |
586 | return; |
587 | ||
736288ba ON |
588 | WARN_ON(!uprobe_filter_is_empty(&tu->filter)); |
589 | ||
a932b738 | 590 | uprobe_unregister(tu->inode, tu->offset, &tu->consumer); |
f3f096cf | 591 | tu->flags &= ~flag; |
f3f096cf SD |
592 | } |
593 | ||
594 | static int uprobe_event_define_fields(struct ftrace_event_call *event_call) | |
595 | { | |
596 | int ret, i; | |
597 | struct uprobe_trace_entry_head field; | |
598 | struct trace_uprobe *tu = (struct trace_uprobe *)event_call->data; | |
599 | ||
600 | DEFINE_FIELD(unsigned long, ip, FIELD_STRING_IP, 0); | |
601 | /* Set argument names as fields */ | |
602 | for (i = 0; i < tu->nr_args; i++) { | |
603 | ret = trace_define_field(event_call, tu->args[i].type->fmttype, | |
604 | tu->args[i].name, | |
605 | sizeof(field) + tu->args[i].offset, | |
606 | tu->args[i].type->size, | |
607 | tu->args[i].type->is_signed, | |
608 | FILTER_OTHER); | |
609 | ||
610 | if (ret) | |
611 | return ret; | |
612 | } | |
613 | return 0; | |
614 | } | |
615 | ||
616 | #define LEN_OR_ZERO (len ? len - pos : 0) | |
617 | static int __set_print_fmt(struct trace_uprobe *tu, char *buf, int len) | |
618 | { | |
619 | const char *fmt, *arg; | |
620 | int i; | |
621 | int pos = 0; | |
622 | ||
623 | fmt = "(%lx)"; | |
624 | arg = "REC->" FIELD_STRING_IP; | |
625 | ||
626 | /* When len=0, we just calculate the needed length */ | |
627 | ||
628 | pos += snprintf(buf + pos, LEN_OR_ZERO, "\"%s", fmt); | |
629 | ||
630 | for (i = 0; i < tu->nr_args; i++) { | |
631 | pos += snprintf(buf + pos, LEN_OR_ZERO, " %s=%s", | |
632 | tu->args[i].name, tu->args[i].type->fmt); | |
633 | } | |
634 | ||
635 | pos += snprintf(buf + pos, LEN_OR_ZERO, "\", %s", arg); | |
636 | ||
637 | for (i = 0; i < tu->nr_args; i++) { | |
638 | pos += snprintf(buf + pos, LEN_OR_ZERO, ", REC->%s", | |
639 | tu->args[i].name); | |
640 | } | |
641 | ||
642 | return pos; /* return the length of print_fmt */ | |
643 | } | |
644 | #undef LEN_OR_ZERO | |
645 | ||
646 | static int set_print_fmt(struct trace_uprobe *tu) | |
647 | { | |
648 | char *print_fmt; | |
649 | int len; | |
650 | ||
651 | /* First: called with 0 length to calculate the needed length */ | |
652 | len = __set_print_fmt(tu, NULL, 0); | |
653 | print_fmt = kmalloc(len + 1, GFP_KERNEL); | |
654 | if (!print_fmt) | |
655 | return -ENOMEM; | |
656 | ||
657 | /* Second: actually write the @print_fmt */ | |
658 | __set_print_fmt(tu, print_fmt, len + 1); | |
659 | tu->call.print_fmt = print_fmt; | |
660 | ||
661 | return 0; | |
662 | } | |
663 | ||
664 | #ifdef CONFIG_PERF_EVENTS | |
31ba3348 ON |
665 | static bool |
666 | __uprobe_perf_filter(struct trace_uprobe_filter *filter, struct mm_struct *mm) | |
667 | { | |
668 | struct perf_event *event; | |
669 | ||
670 | if (filter->nr_systemwide) | |
671 | return true; | |
672 | ||
673 | list_for_each_entry(event, &filter->perf_events, hw.tp_list) { | |
674 | if (event->hw.tp_target->mm == mm) | |
675 | return true; | |
676 | } | |
677 | ||
678 | return false; | |
679 | } | |
680 | ||
736288ba ON |
681 | static int uprobe_perf_open(struct trace_uprobe *tu, struct perf_event *event) |
682 | { | |
683 | write_lock(&tu->filter.rwlock); | |
684 | if (event->hw.tp_target) | |
685 | list_add(&event->hw.tp_list, &tu->filter.perf_events); | |
686 | else | |
687 | tu->filter.nr_systemwide++; | |
688 | write_unlock(&tu->filter.rwlock); | |
689 | ||
31ba3348 ON |
690 | uprobe_apply(tu->inode, tu->offset, &tu->consumer, true); |
691 | ||
736288ba ON |
692 | return 0; |
693 | } | |
694 | ||
695 | static int uprobe_perf_close(struct trace_uprobe *tu, struct perf_event *event) | |
696 | { | |
697 | write_lock(&tu->filter.rwlock); | |
698 | if (event->hw.tp_target) | |
699 | list_del(&event->hw.tp_list); | |
700 | else | |
701 | tu->filter.nr_systemwide--; | |
702 | write_unlock(&tu->filter.rwlock); | |
703 | ||
31ba3348 ON |
704 | uprobe_apply(tu->inode, tu->offset, &tu->consumer, false); |
705 | ||
736288ba ON |
706 | return 0; |
707 | } | |
708 | ||
31ba3348 ON |
709 | static bool uprobe_perf_filter(struct uprobe_consumer *uc, |
710 | enum uprobe_filter_ctx ctx, struct mm_struct *mm) | |
711 | { | |
712 | struct trace_uprobe *tu; | |
713 | int ret; | |
714 | ||
715 | tu = container_of(uc, struct trace_uprobe, consumer); | |
716 | read_lock(&tu->filter.rwlock); | |
717 | ret = __uprobe_perf_filter(&tu->filter, mm); | |
718 | read_unlock(&tu->filter.rwlock); | |
719 | ||
720 | return ret; | |
721 | } | |
722 | ||
f3f096cf SD |
723 | /* uprobe profile handler */ |
724 | static void uprobe_perf_func(struct trace_uprobe *tu, struct pt_regs *regs) | |
725 | { | |
726 | struct ftrace_event_call *call = &tu->call; | |
727 | struct uprobe_trace_entry_head *entry; | |
728 | struct hlist_head *head; | |
729 | u8 *data; | |
730 | int size, __size, i; | |
731 | int rctx; | |
732 | ||
733 | __size = sizeof(*entry) + tu->size; | |
734 | size = ALIGN(__size + sizeof(u32), sizeof(u64)); | |
735 | size -= sizeof(u32); | |
736 | if (WARN_ONCE(size > PERF_MAX_TRACE_SIZE, "profile buffer not large enough")) | |
737 | return; | |
738 | ||
739 | preempt_disable(); | |
740 | ||
741 | entry = perf_trace_buf_prepare(size, call->event.type, regs, &rctx); | |
742 | if (!entry) | |
743 | goto out; | |
744 | ||
74e59dfc | 745 | entry->ip = instruction_pointer(task_pt_regs(current)); |
f3f096cf SD |
746 | data = (u8 *)&entry[1]; |
747 | for (i = 0; i < tu->nr_args; i++) | |
748 | call_fetch(&tu->args[i].fetch, regs, data + tu->args[i].offset); | |
749 | ||
750 | head = this_cpu_ptr(call->perf_events); | |
e6dab5ff | 751 | perf_trace_buf_submit(entry, size, rctx, entry->ip, 1, regs, head, NULL); |
f3f096cf SD |
752 | |
753 | out: | |
754 | preempt_enable(); | |
755 | } | |
756 | #endif /* CONFIG_PERF_EVENTS */ | |
757 | ||
758 | static | |
759 | int trace_uprobe_register(struct ftrace_event_call *event, enum trace_reg type, void *data) | |
760 | { | |
761 | struct trace_uprobe *tu = (struct trace_uprobe *)event->data; | |
762 | ||
763 | switch (type) { | |
764 | case TRACE_REG_REGISTER: | |
31ba3348 | 765 | return probe_event_enable(tu, TP_FLAG_TRACE, NULL); |
f3f096cf SD |
766 | |
767 | case TRACE_REG_UNREGISTER: | |
768 | probe_event_disable(tu, TP_FLAG_TRACE); | |
769 | return 0; | |
770 | ||
771 | #ifdef CONFIG_PERF_EVENTS | |
772 | case TRACE_REG_PERF_REGISTER: | |
31ba3348 | 773 | return probe_event_enable(tu, TP_FLAG_PROFILE, uprobe_perf_filter); |
f3f096cf SD |
774 | |
775 | case TRACE_REG_PERF_UNREGISTER: | |
776 | probe_event_disable(tu, TP_FLAG_PROFILE); | |
777 | return 0; | |
736288ba ON |
778 | |
779 | case TRACE_REG_PERF_OPEN: | |
780 | return uprobe_perf_open(tu, data); | |
781 | ||
782 | case TRACE_REG_PERF_CLOSE: | |
783 | return uprobe_perf_close(tu, data); | |
784 | ||
f3f096cf SD |
785 | #endif |
786 | default: | |
787 | return 0; | |
788 | } | |
789 | return 0; | |
790 | } | |
791 | ||
792 | static int uprobe_dispatcher(struct uprobe_consumer *con, struct pt_regs *regs) | |
793 | { | |
f3f096cf SD |
794 | struct trace_uprobe *tu; |
795 | ||
a932b738 | 796 | tu = container_of(con, struct trace_uprobe, consumer); |
1b47aefd | 797 | tu->nhit++; |
f3f096cf SD |
798 | |
799 | if (tu->flags & TP_FLAG_TRACE) | |
800 | uprobe_trace_func(tu, regs); | |
801 | ||
802 | #ifdef CONFIG_PERF_EVENTS | |
803 | if (tu->flags & TP_FLAG_PROFILE) | |
804 | uprobe_perf_func(tu, regs); | |
805 | #endif | |
806 | return 0; | |
807 | } | |
808 | ||
809 | static struct trace_event_functions uprobe_funcs = { | |
810 | .trace = print_uprobe_event | |
811 | }; | |
812 | ||
813 | static int register_uprobe_event(struct trace_uprobe *tu) | |
814 | { | |
815 | struct ftrace_event_call *call = &tu->call; | |
816 | int ret; | |
817 | ||
818 | /* Initialize ftrace_event_call */ | |
819 | INIT_LIST_HEAD(&call->class->fields); | |
820 | call->event.funcs = &uprobe_funcs; | |
821 | call->class->define_fields = uprobe_event_define_fields; | |
822 | ||
823 | if (set_print_fmt(tu) < 0) | |
824 | return -ENOMEM; | |
825 | ||
826 | ret = register_ftrace_event(&call->event); | |
827 | if (!ret) { | |
828 | kfree(call->print_fmt); | |
829 | return -ENODEV; | |
830 | } | |
831 | call->flags = 0; | |
832 | call->class->reg = trace_uprobe_register; | |
833 | call->data = tu; | |
834 | ret = trace_add_event_call(call); | |
835 | ||
836 | if (ret) { | |
837 | pr_info("Failed to register uprobe event: %s\n", call->name); | |
838 | kfree(call->print_fmt); | |
839 | unregister_ftrace_event(&call->event); | |
840 | } | |
841 | ||
842 | return ret; | |
843 | } | |
844 | ||
845 | static void unregister_uprobe_event(struct trace_uprobe *tu) | |
846 | { | |
847 | /* tu->event is unregistered in trace_remove_event_call() */ | |
848 | trace_remove_event_call(&tu->call); | |
849 | kfree(tu->call.print_fmt); | |
850 | tu->call.print_fmt = NULL; | |
851 | } | |
852 | ||
853 | /* Make a trace interface for controling probe points */ | |
854 | static __init int init_uprobe_trace(void) | |
855 | { | |
856 | struct dentry *d_tracer; | |
857 | ||
858 | d_tracer = tracing_init_dentry(); | |
859 | if (!d_tracer) | |
860 | return 0; | |
861 | ||
862 | trace_create_file("uprobe_events", 0644, d_tracer, | |
863 | NULL, &uprobe_events_ops); | |
864 | /* Profile interface */ | |
865 | trace_create_file("uprobe_profile", 0444, d_tracer, | |
866 | NULL, &uprobe_profile_ops); | |
867 | return 0; | |
868 | } | |
869 | ||
870 | fs_initcall(init_uprobe_trace); |