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x86/xen: resume timer irqs early
[linux/fpc-iii.git] / kernel / trace / trace_uprobe.c
blob272261b5f94ff84e3291be05aaa3b1a8c1ca00ca
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 #include <linux/string.h>
26
27 #include "trace_probe.h"
28
29 #define UPROBE_EVENT_SYSTEM "uprobes"
30
31 struct uprobe_trace_entry_head {
32 struct trace_entry ent;
33 unsigned long vaddr[];
34 };
35
36 #define SIZEOF_TRACE_ENTRY(is_return) \
37 (sizeof(struct uprobe_trace_entry_head) + \
38 sizeof(unsigned long) * (is_return ? 2 : 1))
39
40 #define DATAOF_TRACE_ENTRY(entry, is_return) \
41 ((void*)(entry) + SIZEOF_TRACE_ENTRY(is_return))
42
43 struct trace_uprobe_filter {
44 rwlock_t rwlock;
45 int nr_systemwide;
46 struct list_head perf_events;
47 };
48
49 /*
50 * uprobe event core functions
51 */
52 struct trace_uprobe {
53 struct list_head list;
54 struct ftrace_event_class class;
55 struct ftrace_event_call call;
56 struct trace_uprobe_filter filter;
57 struct uprobe_consumer consumer;
58 struct inode *inode;
59 char *filename;
60 unsigned long offset;
61 unsigned long nhit;
62 unsigned int flags; /* For TP_FLAG_* */
63 ssize_t size; /* trace entry size */
64 unsigned int nr_args;
65 struct probe_arg args[];
66 };
67
68 #define SIZEOF_TRACE_UPROBE(n) \
69 (offsetof(struct trace_uprobe, args) + \
70 (sizeof(struct probe_arg) * (n)))
71
72 static int register_uprobe_event(struct trace_uprobe *tu);
73 static int unregister_uprobe_event(struct trace_uprobe *tu);
74
75 static DEFINE_MUTEX(uprobe_lock);
76 static LIST_HEAD(uprobe_list);
77
78 static int uprobe_dispatcher(struct uprobe_consumer *con, struct pt_regs *regs);
79 static int uretprobe_dispatcher(struct uprobe_consumer *con,
80 unsigned long func, struct pt_regs *regs);
81
82 static inline void init_trace_uprobe_filter(struct trace_uprobe_filter *filter)
83 {
84 rwlock_init(&filter->rwlock);
85 filter->nr_systemwide = 0;
86 INIT_LIST_HEAD(&filter->perf_events);
87 }
88
89 static inline bool uprobe_filter_is_empty(struct trace_uprobe_filter *filter)
90 {
91 return !filter->nr_systemwide && list_empty(&filter->perf_events);
92 }
93
94 static inline bool is_ret_probe(struct trace_uprobe *tu)
95 {
96 return tu->consumer.ret_handler != NULL;
97 }
98
99 /*
100 * Allocate new trace_uprobe and initialize it (including uprobes).
101 */
102 static struct trace_uprobe *
103 alloc_trace_uprobe(const char *group, const char *event, int nargs, bool is_ret)
104 {
105 struct trace_uprobe *tu;
106
107 if (!event || !is_good_name(event))
108 return ERR_PTR(-EINVAL);
109
110 if (!group || !is_good_name(group))
111 return ERR_PTR(-EINVAL);
112
113 tu = kzalloc(SIZEOF_TRACE_UPROBE(nargs), GFP_KERNEL);
114 if (!tu)
115 return ERR_PTR(-ENOMEM);
116
117 tu->call.class = &tu->class;
118 tu->call.name = kstrdup(event, GFP_KERNEL);
119 if (!tu->call.name)
120 goto error;
121
122 tu->class.system = kstrdup(group, GFP_KERNEL);
123 if (!tu->class.system)
124 goto error;
125
126 INIT_LIST_HEAD(&tu->list);
127 tu->consumer.handler = uprobe_dispatcher;
128 if (is_ret)
129 tu->consumer.ret_handler = uretprobe_dispatcher;
130 init_trace_uprobe_filter(&tu->filter);
131 return tu;
132
133 error:
134 kfree(tu->call.name);
135 kfree(tu);
136
137 return ERR_PTR(-ENOMEM);
138 }
139
140 static void free_trace_uprobe(struct trace_uprobe *tu)
141 {
142 int i;
143
144 for (i = 0; i < tu->nr_args; i++)
145 traceprobe_free_probe_arg(&tu->args[i]);
146
147 iput(tu->inode);
148 kfree(tu->call.class->system);
149 kfree(tu->call.name);
150 kfree(tu->filename);
151 kfree(tu);
152 }
153
154 static struct trace_uprobe *find_probe_event(const char *event, const char *group)
155 {
156 struct trace_uprobe *tu;
157
158 list_for_each_entry(tu, &uprobe_list, list)
159 if (strcmp(tu->call.name, event) == 0 &&
160 strcmp(tu->call.class->system, group) == 0)
161 return tu;
162
163 return NULL;
164 }
165
166 /* Unregister a trace_uprobe and probe_event: call with locking uprobe_lock */
167 static int unregister_trace_uprobe(struct trace_uprobe *tu)
168 {
169 int ret;
170
171 ret = unregister_uprobe_event(tu);
172 if (ret)
173 return ret;
174
175 list_del(&tu->list);
176 free_trace_uprobe(tu);
177 return 0;
178 }
179
180 /* Register a trace_uprobe and probe_event */
181 static int register_trace_uprobe(struct trace_uprobe *tu)
182 {
183 struct trace_uprobe *old_tp;
184 int ret;
185
186 mutex_lock(&uprobe_lock);
187
188 /* register as an event */
189 old_tp = find_probe_event(tu->call.name, tu->call.class->system);
190 if (old_tp) {
191 /* delete old event */
192 ret = unregister_trace_uprobe(old_tp);
193 if (ret)
194 goto end;
195 }
196
197 ret = register_uprobe_event(tu);
198 if (ret) {
199 pr_warning("Failed to register probe event(%d)\n", ret);
200 goto end;
201 }
202
203 list_add_tail(&tu->list, &uprobe_list);
204
205 end:
206 mutex_unlock(&uprobe_lock);
207
208 return ret;
209 }
210
211 /*
212 * Argument syntax:
213 * - Add uprobe: p|r[:[GRP/]EVENT] PATH:SYMBOL [FETCHARGS]
214 *
215 * - Remove uprobe: -:[GRP/]EVENT
216 */
217 static int create_trace_uprobe(int argc, char **argv)
218 {
219 struct trace_uprobe *tu;
220 struct inode *inode;
221 char *arg, *event, *group, *filename;
222 char buf[MAX_EVENT_NAME_LEN];
223 struct path path;
224 unsigned long offset;
225 bool is_delete, is_return;
226 int i, ret;
227
228 inode = NULL;
229 ret = 0;
230 is_delete = false;
231 is_return = false;
232 event = NULL;
233 group = NULL;
234
235 /* argc must be >= 1 */
236 if (argv[0][0] == '-')
237 is_delete = true;
238 else if (argv[0][0] == 'r')
239 is_return = true;
240 else if (argv[0][0] != 'p') {
241 pr_info("Probe definition must be started with 'p', 'r' or '-'.\n");
242 return -EINVAL;
243 }
244
245 if (argv[0][1] == ':') {
246 event = &argv[0][2];
247 arg = strchr(event, '/');
248
249 if (arg) {
250 group = event;
251 event = arg + 1;
252 event[-1] = '\0';
253
254 if (strlen(group) == 0) {
255 pr_info("Group name is not specified\n");
256 return -EINVAL;
257 }
258 }
259 if (strlen(event) == 0) {
260 pr_info("Event name is not specified\n");
261 return -EINVAL;
262 }
263 }
264 if (!group)
265 group = UPROBE_EVENT_SYSTEM;
266
267 if (is_delete) {
268 int ret;
269
270 if (!event) {
271 pr_info("Delete command needs an event name.\n");
272 return -EINVAL;
273 }
274 mutex_lock(&uprobe_lock);
275 tu = find_probe_event(event, group);
276
277 if (!tu) {
278 mutex_unlock(&uprobe_lock);
279 pr_info("Event %s/%s doesn't exist.\n", group, event);
280 return -ENOENT;
281 }
282 /* delete an event */
283 ret = unregister_trace_uprobe(tu);
284 mutex_unlock(&uprobe_lock);
285 return ret;
286 }
287
288 if (argc < 2) {
289 pr_info("Probe point is not specified.\n");
290 return -EINVAL;
291 }
292 if (isdigit(argv[1][0])) {
293 pr_info("probe point must be have a filename.\n");
294 return -EINVAL;
295 }
296 arg = strchr(argv[1], ':');
297 if (!arg) {
298 ret = -EINVAL;
299 goto fail_address_parse;
300 }
301
302 *arg++ = '\0';
303 filename = argv[1];
304 ret = kern_path(filename, LOOKUP_FOLLOW, &path);
305 if (ret)
306 goto fail_address_parse;
307
308 inode = igrab(path.dentry->d_inode);
309 path_put(&path);
310
311 if (!inode || !S_ISREG(inode->i_mode)) {
312 ret = -EINVAL;
313 goto fail_address_parse;
314 }
315
316 ret = kstrtoul(arg, 0, &offset);
317 if (ret)
318 goto fail_address_parse;
319
320 argc -= 2;
321 argv += 2;
322
323 /* setup a probe */
324 if (!event) {
325 char *tail;
326 char *ptr;
327
328 tail = kstrdup(kbasename(filename), GFP_KERNEL);
329 if (!tail) {
330 ret = -ENOMEM;
331 goto fail_address_parse;
332 }
333
334 ptr = strpbrk(tail, ".-_");
335 if (ptr)
336 *ptr = '\0';
337
338 snprintf(buf, MAX_EVENT_NAME_LEN, "%c_%s_0x%lx", 'p', tail, offset);
339 event = buf;
340 kfree(tail);
341 }
342
343 tu = alloc_trace_uprobe(group, event, argc, is_return);
344 if (IS_ERR(tu)) {
345 pr_info("Failed to allocate trace_uprobe.(%d)\n", (int)PTR_ERR(tu));
346 ret = PTR_ERR(tu);
347 goto fail_address_parse;
348 }
349 tu->offset = offset;
350 tu->inode = inode;
351 tu->filename = kstrdup(filename, GFP_KERNEL);
352
353 if (!tu->filename) {
354 pr_info("Failed to allocate filename.\n");
355 ret = -ENOMEM;
356 goto error;
357 }
358
359 /* parse arguments */
360 ret = 0;
361 for (i = 0; i < argc && i < MAX_TRACE_ARGS; i++) {
362 /* Increment count for freeing args in error case */
363 tu->nr_args++;
364
365 /* Parse argument name */
366 arg = strchr(argv[i], '=');
367 if (arg) {
368 *arg++ = '\0';
369 tu->args[i].name = kstrdup(argv[i], GFP_KERNEL);
370 } else {
371 arg = argv[i];
372 /* If argument name is omitted, set "argN" */
373 snprintf(buf, MAX_EVENT_NAME_LEN, "arg%d", i + 1);
374 tu->args[i].name = kstrdup(buf, GFP_KERNEL);
375 }
376
377 if (!tu->args[i].name) {
378 pr_info("Failed to allocate argument[%d] name.\n", i);
379 ret = -ENOMEM;
380 goto error;
381 }
382
383 if (!is_good_name(tu->args[i].name)) {
384 pr_info("Invalid argument[%d] name: %s\n", i, tu->args[i].name);
385 ret = -EINVAL;
386 goto error;
387 }
388
389 if (traceprobe_conflict_field_name(tu->args[i].name, tu->args, i)) {
390 pr_info("Argument[%d] name '%s' conflicts with "
391 "another field.\n", i, argv[i]);
392 ret = -EINVAL;
393 goto error;
394 }
395
396 /* Parse fetch argument */
397 ret = traceprobe_parse_probe_arg(arg, &tu->size, &tu->args[i], false, false);
398 if (ret) {
399 pr_info("Parse error at argument[%d]. (%d)\n", i, ret);
400 goto error;
401 }
402 }
403
404 ret = register_trace_uprobe(tu);
405 if (ret)
406 goto error;
407 return 0;
408
409 error:
410 free_trace_uprobe(tu);
411 return ret;
412
413 fail_address_parse:
414 if (inode)
415 iput(inode);
416
417 pr_info("Failed to parse address or file.\n");
418
419 return ret;
420 }
421
422 static int cleanup_all_probes(void)
423 {
424 struct trace_uprobe *tu;
425 int ret = 0;
426
427 mutex_lock(&uprobe_lock);
428 while (!list_empty(&uprobe_list)) {
429 tu = list_entry(uprobe_list.next, struct trace_uprobe, list);
430 ret = unregister_trace_uprobe(tu);
431 if (ret)
432 break;
433 }
434 mutex_unlock(&uprobe_lock);
435 return ret;
436 }
437
438 /* Probes listing interfaces */
439 static void *probes_seq_start(struct seq_file *m, loff_t *pos)
440 {
441 mutex_lock(&uprobe_lock);
442 return seq_list_start(&uprobe_list, *pos);
443 }
444
445 static void *probes_seq_next(struct seq_file *m, void *v, loff_t *pos)
446 {
447 return seq_list_next(v, &uprobe_list, pos);
448 }
449
450 static void probes_seq_stop(struct seq_file *m, void *v)
451 {
452 mutex_unlock(&uprobe_lock);
453 }
454
455 static int probes_seq_show(struct seq_file *m, void *v)
456 {
457 struct trace_uprobe *tu = v;
458 char c = is_ret_probe(tu) ? 'r' : 'p';
459 int i;
460
461 seq_printf(m, "%c:%s/%s", c, tu->call.class->system, tu->call.name);
462 seq_printf(m, " %s:0x%p", tu->filename, (void *)tu->offset);
463
464 for (i = 0; i < tu->nr_args; i++)
465 seq_printf(m, " %s=%s", tu->args[i].name, tu->args[i].comm);
466
467 seq_printf(m, "\n");
468 return 0;
469 }
470
471 static const struct seq_operations probes_seq_op = {
472 .start = probes_seq_start,
473 .next = probes_seq_next,
474 .stop = probes_seq_stop,
475 .show = probes_seq_show
476 };
477
478 static int probes_open(struct inode *inode, struct file *file)
479 {
480 int ret;
481
482 if ((file->f_mode & FMODE_WRITE) && (file->f_flags & O_TRUNC)) {
483 ret = cleanup_all_probes();
484 if (ret)
485 return ret;
486 }
487
488 return seq_open(file, &probes_seq_op);
489 }
490
491 static ssize_t probes_write(struct file *file, const char __user *buffer,
492 size_t count, loff_t *ppos)
493 {
494 return traceprobe_probes_write(file, buffer, count, ppos, create_trace_uprobe);
495 }
496
497 static const struct file_operations uprobe_events_ops = {
498 .owner = THIS_MODULE,
499 .open = probes_open,
500 .read = seq_read,
501 .llseek = seq_lseek,
502 .release = seq_release,
503 .write = probes_write,
504 };
505
506 /* Probes profiling interfaces */
507 static int probes_profile_seq_show(struct seq_file *m, void *v)
508 {
509 struct trace_uprobe *tu = v;
510
511 seq_printf(m, " %s %-44s %15lu\n", tu->filename, tu->call.name, tu->nhit);
512 return 0;
513 }
514
515 static const struct seq_operations profile_seq_op = {
516 .start = probes_seq_start,
517 .next = probes_seq_next,
518 .stop = probes_seq_stop,
519 .show = probes_profile_seq_show
520 };
521
522 static int profile_open(struct inode *inode, struct file *file)
523 {
524 return seq_open(file, &profile_seq_op);
525 }
526
527 static const struct file_operations uprobe_profile_ops = {
528 .owner = THIS_MODULE,
529 .open = profile_open,
530 .read = seq_read,
531 .llseek = seq_lseek,
532 .release = seq_release,
533 };
534
535 static void uprobe_trace_print(struct trace_uprobe *tu,
536 unsigned long func, struct pt_regs *regs)
537 {
538 struct uprobe_trace_entry_head *entry;
539 struct ring_buffer_event *event;
540 struct ring_buffer *buffer;
541 void *data;
542 int size, i;
543 struct ftrace_event_call *call = &tu->call;
544
545 size = SIZEOF_TRACE_ENTRY(is_ret_probe(tu));
546 event = trace_current_buffer_lock_reserve(&buffer, call->event.type,
547 size + tu->size, 0, 0);
548 if (!event)
549 return;
550
551 entry = ring_buffer_event_data(event);
552 if (is_ret_probe(tu)) {
553 entry->vaddr[0] = func;
554 entry->vaddr[1] = instruction_pointer(regs);
555 data = DATAOF_TRACE_ENTRY(entry, true);
556 } else {
557 entry->vaddr[0] = instruction_pointer(regs);
558 data = DATAOF_TRACE_ENTRY(entry, false);
559 }
560
561 for (i = 0; i < tu->nr_args; i++)
562 call_fetch(&tu->args[i].fetch, regs, data + tu->args[i].offset);
563
564 if (!filter_current_check_discard(buffer, call, entry, event))
565 trace_buffer_unlock_commit(buffer, event, 0, 0);
566 }
567
568 /* uprobe handler */
569 static int uprobe_trace_func(struct trace_uprobe *tu, struct pt_regs *regs)
570 {
571 if (!is_ret_probe(tu))
572 uprobe_trace_print(tu, 0, regs);
573 return 0;
574 }
575
576 static void uretprobe_trace_func(struct trace_uprobe *tu, unsigned long func,
577 struct pt_regs *regs)
578 {
579 uprobe_trace_print(tu, func, regs);
580 }
581
582 /* Event entry printers */
583 static enum print_line_t
584 print_uprobe_event(struct trace_iterator *iter, int flags, struct trace_event *event)
585 {
586 struct uprobe_trace_entry_head *entry;
587 struct trace_seq *s = &iter->seq;
588 struct trace_uprobe *tu;
589 u8 *data;
590 int i;
591
592 entry = (struct uprobe_trace_entry_head *)iter->ent;
593 tu = container_of(event, struct trace_uprobe, call.event);
594
595 if (is_ret_probe(tu)) {
596 if (!trace_seq_printf(s, "%s: (0x%lx <- 0x%lx)", tu->call.name,
597 entry->vaddr[1], entry->vaddr[0]))
598 goto partial;
599 data = DATAOF_TRACE_ENTRY(entry, true);
600 } else {
601 if (!trace_seq_printf(s, "%s: (0x%lx)", tu->call.name,
602 entry->vaddr[0]))
603 goto partial;
604 data = DATAOF_TRACE_ENTRY(entry, false);
605 }
606
607 for (i = 0; i < tu->nr_args; i++) {
608 if (!tu->args[i].type->print(s, tu->args[i].name,
609 data + tu->args[i].offset, entry))
610 goto partial;
611 }
612
613 if (trace_seq_puts(s, "\n"))
614 return TRACE_TYPE_HANDLED;
615
616 partial:
617 return TRACE_TYPE_PARTIAL_LINE;
618 }
619
620 static inline bool is_trace_uprobe_enabled(struct trace_uprobe *tu)
621 {
622 return tu->flags & (TP_FLAG_TRACE | TP_FLAG_PROFILE);
623 }
624
625 typedef bool (*filter_func_t)(struct uprobe_consumer *self,
626 enum uprobe_filter_ctx ctx,
627 struct mm_struct *mm);
628
629 static int
630 probe_event_enable(struct trace_uprobe *tu, int flag, filter_func_t filter)
631 {
632 int ret = 0;
633
634 if (is_trace_uprobe_enabled(tu))
635 return -EINTR;
636
637 WARN_ON(!uprobe_filter_is_empty(&tu->filter));
638
639 tu->flags |= flag;
640 tu->consumer.filter = filter;
641 ret = uprobe_register(tu->inode, tu->offset, &tu->consumer);
642 if (ret)
643 tu->flags &= ~flag;
644
645 return ret;
646 }
647
648 static void probe_event_disable(struct trace_uprobe *tu, int flag)
649 {
650 if (!is_trace_uprobe_enabled(tu))
651 return;
652
653 WARN_ON(!uprobe_filter_is_empty(&tu->filter));
654
655 uprobe_unregister(tu->inode, tu->offset, &tu->consumer);
656 tu->flags &= ~flag;
657 }
658
659 static int uprobe_event_define_fields(struct ftrace_event_call *event_call)
660 {
661 int ret, i, size;
662 struct uprobe_trace_entry_head field;
663 struct trace_uprobe *tu = event_call->data;
664
665 if (is_ret_probe(tu)) {
666 DEFINE_FIELD(unsigned long, vaddr[0], FIELD_STRING_FUNC, 0);
667 DEFINE_FIELD(unsigned long, vaddr[1], FIELD_STRING_RETIP, 0);
668 size = SIZEOF_TRACE_ENTRY(true);
669 } else {
670 DEFINE_FIELD(unsigned long, vaddr[0], FIELD_STRING_IP, 0);
671 size = SIZEOF_TRACE_ENTRY(false);
672 }
673 /* Set argument names as fields */
674 for (i = 0; i < tu->nr_args; i++) {
675 ret = trace_define_field(event_call, tu->args[i].type->fmttype,
676 tu->args[i].name,
677 size + tu->args[i].offset,
678 tu->args[i].type->size,
679 tu->args[i].type->is_signed,
680 FILTER_OTHER);
681
682 if (ret)
683 return ret;
684 }
685 return 0;
686 }
687
688 #define LEN_OR_ZERO (len ? len - pos : 0)
689 static int __set_print_fmt(struct trace_uprobe *tu, char *buf, int len)
690 {
691 const char *fmt, *arg;
692 int i;
693 int pos = 0;
694
695 if (is_ret_probe(tu)) {
696 fmt = "(%lx <- %lx)";
697 arg = "REC->" FIELD_STRING_FUNC ", REC->" FIELD_STRING_RETIP;
698 } else {
699 fmt = "(%lx)";
700 arg = "REC->" FIELD_STRING_IP;
701 }
702
703 /* When len=0, we just calculate the needed length */
704
705 pos += snprintf(buf + pos, LEN_OR_ZERO, "\"%s", fmt);
706
707 for (i = 0; i < tu->nr_args; i++) {
708 pos += snprintf(buf + pos, LEN_OR_ZERO, " %s=%s",
709 tu->args[i].name, tu->args[i].type->fmt);
710 }
711
712 pos += snprintf(buf + pos, LEN_OR_ZERO, "\", %s", arg);
713
714 for (i = 0; i < tu->nr_args; i++) {
715 pos += snprintf(buf + pos, LEN_OR_ZERO, ", REC->%s",
716 tu->args[i].name);
717 }
718
719 return pos; /* return the length of print_fmt */
720 }
721 #undef LEN_OR_ZERO
722
723 static int set_print_fmt(struct trace_uprobe *tu)
724 {
725 char *print_fmt;
726 int len;
727
728 /* First: called with 0 length to calculate the needed length */
729 len = __set_print_fmt(tu, NULL, 0);
730 print_fmt = kmalloc(len + 1, GFP_KERNEL);
731 if (!print_fmt)
732 return -ENOMEM;
733
734 /* Second: actually write the @print_fmt */
735 __set_print_fmt(tu, print_fmt, len + 1);
736 tu->call.print_fmt = print_fmt;
737
738 return 0;
739 }
740
741 #ifdef CONFIG_PERF_EVENTS
742 static bool
743 __uprobe_perf_filter(struct trace_uprobe_filter *filter, struct mm_struct *mm)
744 {
745 struct perf_event *event;
746
747 if (filter->nr_systemwide)
748 return true;
749
750 list_for_each_entry(event, &filter->perf_events, hw.tp_list) {
751 if (event->hw.tp_target->mm == mm)
752 return true;
753 }
754
755 return false;
756 }
757
758 static inline bool
759 uprobe_filter_event(struct trace_uprobe *tu, struct perf_event *event)
760 {
761 return __uprobe_perf_filter(&tu->filter, event->hw.tp_target->mm);
762 }
763
764 static int uprobe_perf_open(struct trace_uprobe *tu, struct perf_event *event)
765 {
766 bool done;
767
768 write_lock(&tu->filter.rwlock);
769 if (event->hw.tp_target) {
770 /*
771 * event->parent != NULL means copy_process(), we can avoid
772 * uprobe_apply(). current->mm must be probed and we can rely
773 * on dup_mmap() which preserves the already installed bp's.
774 *
775 * attr.enable_on_exec means that exec/mmap will install the
776 * breakpoints we need.
777 */
778 done = tu->filter.nr_systemwide ||
779 event->parent || event->attr.enable_on_exec ||
780 uprobe_filter_event(tu, event);
781 list_add(&event->hw.tp_list, &tu->filter.perf_events);
782 } else {
783 done = tu->filter.nr_systemwide;
784 tu->filter.nr_systemwide++;
785 }
786 write_unlock(&tu->filter.rwlock);
787
788 if (!done)
789 uprobe_apply(tu->inode, tu->offset, &tu->consumer, true);
790
791 return 0;
792 }
793
794 static int uprobe_perf_close(struct trace_uprobe *tu, struct perf_event *event)
795 {
796 bool done;
797
798 write_lock(&tu->filter.rwlock);
799 if (event->hw.tp_target) {
800 list_del(&event->hw.tp_list);
801 done = tu->filter.nr_systemwide ||
802 (event->hw.tp_target->flags & PF_EXITING) ||
803 uprobe_filter_event(tu, event);
804 } else {
805 tu->filter.nr_systemwide--;
806 done = tu->filter.nr_systemwide;
807 }
808 write_unlock(&tu->filter.rwlock);
809
810 if (!done)
811 uprobe_apply(tu->inode, tu->offset, &tu->consumer, false);
812
813 return 0;
814 }
815
816 static bool uprobe_perf_filter(struct uprobe_consumer *uc,
817 enum uprobe_filter_ctx ctx, struct mm_struct *mm)
818 {
819 struct trace_uprobe *tu;
820 int ret;
821
822 tu = container_of(uc, struct trace_uprobe, consumer);
823 read_lock(&tu->filter.rwlock);
824 ret = __uprobe_perf_filter(&tu->filter, mm);
825 read_unlock(&tu->filter.rwlock);
826
827 return ret;
828 }
829
830 static void uprobe_perf_print(struct trace_uprobe *tu,
831 unsigned long func, struct pt_regs *regs)
832 {
833 struct ftrace_event_call *call = &tu->call;
834 struct uprobe_trace_entry_head *entry;
835 struct hlist_head *head;
836 void *data;
837 int size, rctx, i;
838
839 size = SIZEOF_TRACE_ENTRY(is_ret_probe(tu));
840 size = ALIGN(size + tu->size + sizeof(u32), sizeof(u64)) - sizeof(u32);
841
842 preempt_disable();
843 head = this_cpu_ptr(call->perf_events);
844 if (hlist_empty(head))
845 goto out;
846
847 entry = perf_trace_buf_prepare(size, call->event.type, regs, &rctx);
848 if (!entry)
849 goto out;
850
851 if (is_ret_probe(tu)) {
852 entry->vaddr[0] = func;
853 entry->vaddr[1] = instruction_pointer(regs);
854 data = DATAOF_TRACE_ENTRY(entry, true);
855 } else {
856 entry->vaddr[0] = instruction_pointer(regs);
857 data = DATAOF_TRACE_ENTRY(entry, false);
858 }
859
860 for (i = 0; i < tu->nr_args; i++)
861 call_fetch(&tu->args[i].fetch, regs, data + tu->args[i].offset);
862
863 perf_trace_buf_submit(entry, size, rctx, 0, 1, regs, head, NULL);
864 out:
865 preempt_enable();
866 }
867
868 /* uprobe profile handler */
869 static int uprobe_perf_func(struct trace_uprobe *tu, struct pt_regs *regs)
870 {
871 if (!uprobe_perf_filter(&tu->consumer, 0, current->mm))
872 return UPROBE_HANDLER_REMOVE;
873
874 if (!is_ret_probe(tu))
875 uprobe_perf_print(tu, 0, regs);
876 return 0;
877 }
878
879 static void uretprobe_perf_func(struct trace_uprobe *tu, unsigned long func,
880 struct pt_regs *regs)
881 {
882 uprobe_perf_print(tu, func, regs);
883 }
884 #endif /* CONFIG_PERF_EVENTS */
885
886 static
887 int trace_uprobe_register(struct ftrace_event_call *event, enum trace_reg type, void *data)
888 {
889 struct trace_uprobe *tu = event->data;
890
891 switch (type) {
892 case TRACE_REG_REGISTER:
893 return probe_event_enable(tu, TP_FLAG_TRACE, NULL);
894
895 case TRACE_REG_UNREGISTER:
896 probe_event_disable(tu, TP_FLAG_TRACE);
897 return 0;
898
899 #ifdef CONFIG_PERF_EVENTS
900 case TRACE_REG_PERF_REGISTER:
901 return probe_event_enable(tu, TP_FLAG_PROFILE, uprobe_perf_filter);
902
903 case TRACE_REG_PERF_UNREGISTER:
904 probe_event_disable(tu, TP_FLAG_PROFILE);
905 return 0;
906
907 case TRACE_REG_PERF_OPEN:
908 return uprobe_perf_open(tu, data);
909
910 case TRACE_REG_PERF_CLOSE:
911 return uprobe_perf_close(tu, data);
912
913 #endif
914 default:
915 return 0;
916 }
917 return 0;
918 }
919
920 static int uprobe_dispatcher(struct uprobe_consumer *con, struct pt_regs *regs)
921 {
922 struct trace_uprobe *tu;
923 int ret = 0;
924
925 tu = container_of(con, struct trace_uprobe, consumer);
926 tu->nhit++;
927
928 if (tu->flags & TP_FLAG_TRACE)
929 ret |= uprobe_trace_func(tu, regs);
930
931 #ifdef CONFIG_PERF_EVENTS
932 if (tu->flags & TP_FLAG_PROFILE)
933 ret |= uprobe_perf_func(tu, regs);
934 #endif
935 return ret;
936 }
937
938 static int uretprobe_dispatcher(struct uprobe_consumer *con,
939 unsigned long func, struct pt_regs *regs)
940 {
941 struct trace_uprobe *tu;
942
943 tu = container_of(con, struct trace_uprobe, consumer);
944
945 if (tu->flags & TP_FLAG_TRACE)
946 uretprobe_trace_func(tu, func, regs);
947
948 #ifdef CONFIG_PERF_EVENTS
949 if (tu->flags & TP_FLAG_PROFILE)
950 uretprobe_perf_func(tu, func, regs);
951 #endif
952 return 0;
953 }
954
955 static struct trace_event_functions uprobe_funcs = {
956 .trace = print_uprobe_event
957 };
958
959 static int register_uprobe_event(struct trace_uprobe *tu)
960 {
961 struct ftrace_event_call *call = &tu->call;
962 int ret;
963
964 /* Initialize ftrace_event_call */
965 INIT_LIST_HEAD(&call->class->fields);
966 call->event.funcs = &uprobe_funcs;
967 call->class->define_fields = uprobe_event_define_fields;
968
969 if (set_print_fmt(tu) < 0)
970 return -ENOMEM;
971
972 ret = register_ftrace_event(&call->event);
973 if (!ret) {
974 kfree(call->print_fmt);
975 return -ENODEV;
976 }
977 call->flags = 0;
978 call->class->reg = trace_uprobe_register;
979 call->data = tu;
980 ret = trace_add_event_call(call);
981
982 if (ret) {
983 pr_info("Failed to register uprobe event: %s\n", call->name);
984 kfree(call->print_fmt);
985 unregister_ftrace_event(&call->event);
986 }
987
988 return ret;
989 }
990
991 static int unregister_uprobe_event(struct trace_uprobe *tu)
992 {
993 int ret;
994
995 /* tu->event is unregistered in trace_remove_event_call() */
996 ret = trace_remove_event_call(&tu->call);
997 if (ret)
998 return ret;
999 kfree(tu->call.print_fmt);
1000 tu->call.print_fmt = NULL;
1001 return 0;
1002 }
1003
1004 /* Make a trace interface for controling probe points */
1005 static __init int init_uprobe_trace(void)
1006 {
1007 struct dentry *d_tracer;
1008
1009 d_tracer = tracing_init_dentry();
1010 if (!d_tracer)
1011 return 0;
1012
1013 trace_create_file("uprobe_events", 0644, d_tracer,
1014 NULL, &uprobe_events_ops);
1015 /* Profile interface */
1016 trace_create_file("uprobe_profile", 0444, d_tracer,
1017 NULL, &uprobe_profile_ops);
1018 return 0;
1019 }
1020
1021 fs_initcall(init_uprobe_trace);
Linux with added FPC-III support