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net: fix ifindex collision during namespace removal
[linux/fpc-iii.git] / kernel / trace / trace_uprobe.c
blobc6eee3d9ed005a7a59fa9aa331369774f1bf45d7
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 trace_uprobe_filter filter;
55 struct uprobe_consumer consumer;
56 struct inode *inode;
57 char *filename;
58 unsigned long offset;
59 unsigned long nhit;
60 struct trace_probe tp;
61 };
62
63 #define SIZEOF_TRACE_UPROBE(n) \
64 (offsetof(struct trace_uprobe, tp.args) + \
65 (sizeof(struct probe_arg) * (n)))
66
67 static int register_uprobe_event(struct trace_uprobe *tu);
68 static int unregister_uprobe_event(struct trace_uprobe *tu);
69
70 static DEFINE_MUTEX(uprobe_lock);
71 static LIST_HEAD(uprobe_list);
72
73 struct uprobe_dispatch_data {
74 struct trace_uprobe *tu;
75 unsigned long bp_addr;
76 };
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 #ifdef CONFIG_STACK_GROWSUP
83 static unsigned long adjust_stack_addr(unsigned long addr, unsigned int n)
84 {
85 return addr - (n * sizeof(long));
86 }
87 #else
88 static unsigned long adjust_stack_addr(unsigned long addr, unsigned int n)
89 {
90 return addr + (n * sizeof(long));
91 }
92 #endif
93
94 static unsigned long get_user_stack_nth(struct pt_regs *regs, unsigned int n)
95 {
96 unsigned long ret;
97 unsigned long addr = user_stack_pointer(regs);
98
99 addr = adjust_stack_addr(addr, n);
100
101 if (copy_from_user(&ret, (void __force __user *) addr, sizeof(ret)))
102 return 0;
103
104 return ret;
105 }
106
107 /*
108 * Uprobes-specific fetch functions
109 */
110 #define DEFINE_FETCH_stack(type) \
111 static void FETCH_FUNC_NAME(stack, type)(struct pt_regs *regs, \
112 void *offset, void *dest) \
113 { \
114 *(type *)dest = (type)get_user_stack_nth(regs, \
115 ((unsigned long)offset)); \
116 }
117 DEFINE_BASIC_FETCH_FUNCS(stack)
118 /* No string on the stack entry */
119 #define fetch_stack_string NULL
120 #define fetch_stack_string_size NULL
121
122 #define DEFINE_FETCH_memory(type) \
123 static void FETCH_FUNC_NAME(memory, type)(struct pt_regs *regs, \
124 void *addr, void *dest) \
125 { \
126 type retval; \
127 void __user *vaddr = (void __force __user *) addr; \
128 \
129 if (copy_from_user(&retval, vaddr, sizeof(type))) \
130 *(type *)dest = 0; \
131 else \
132 *(type *) dest = retval; \
133 }
134 DEFINE_BASIC_FETCH_FUNCS(memory)
135 /*
136 * Fetch a null-terminated string. Caller MUST set *(u32 *)dest with max
137 * length and relative data location.
138 */
139 static void FETCH_FUNC_NAME(memory, string)(struct pt_regs *regs,
140 void *addr, void *dest)
141 {
142 long ret;
143 u32 rloc = *(u32 *)dest;
144 int maxlen = get_rloc_len(rloc);
145 u8 *dst = get_rloc_data(dest);
146 void __user *src = (void __force __user *) addr;
147
148 if (!maxlen)
149 return;
150
151 ret = strncpy_from_user(dst, src, maxlen);
152 if (ret == maxlen)
153 dst[ret - 1] = '\0';
154 else if (ret >= 0)
155 /*
156 * Include the terminating null byte. In this case it
157 * was copied by strncpy_from_user but not accounted
158 * for in ret.
159 */
160 ret++;
161
162 if (ret < 0) { /* Failed to fetch string */
163 ((u8 *)get_rloc_data(dest))[0] = '\0';
164 *(u32 *)dest = make_data_rloc(0, get_rloc_offs(rloc));
165 } else {
166 *(u32 *)dest = make_data_rloc(ret, get_rloc_offs(rloc));
167 }
168 }
169
170 static void FETCH_FUNC_NAME(memory, string_size)(struct pt_regs *regs,
171 void *addr, void *dest)
172 {
173 int len;
174 void __user *vaddr = (void __force __user *) addr;
175
176 len = strnlen_user(vaddr, MAX_STRING_SIZE);
177
178 if (len == 0 || len > MAX_STRING_SIZE) /* Failed to check length */
179 *(u32 *)dest = 0;
180 else
181 *(u32 *)dest = len;
182 }
183
184 static unsigned long translate_user_vaddr(void *file_offset)
185 {
186 unsigned long base_addr;
187 struct uprobe_dispatch_data *udd;
188
189 udd = (void *) current->utask->vaddr;
190
191 base_addr = udd->bp_addr - udd->tu->offset;
192 return base_addr + (unsigned long)file_offset;
193 }
194
195 #define DEFINE_FETCH_file_offset(type) \
196 static void FETCH_FUNC_NAME(file_offset, type)(struct pt_regs *regs, \
197 void *offset, void *dest)\
198 { \
199 void *vaddr = (void *)translate_user_vaddr(offset); \
200 \
201 FETCH_FUNC_NAME(memory, type)(regs, vaddr, dest); \
202 }
203 DEFINE_BASIC_FETCH_FUNCS(file_offset)
204 DEFINE_FETCH_file_offset(string)
205 DEFINE_FETCH_file_offset(string_size)
206
207 /* Fetch type information table */
208 static const struct fetch_type uprobes_fetch_type_table[] = {
209 /* Special types */
210 [FETCH_TYPE_STRING] = __ASSIGN_FETCH_TYPE("string", string, string,
211 sizeof(u32), 1, "__data_loc char[]"),
212 [FETCH_TYPE_STRSIZE] = __ASSIGN_FETCH_TYPE("string_size", u32,
213 string_size, sizeof(u32), 0, "u32"),
214 /* Basic types */
215 ASSIGN_FETCH_TYPE(u8, u8, 0),
216 ASSIGN_FETCH_TYPE(u16, u16, 0),
217 ASSIGN_FETCH_TYPE(u32, u32, 0),
218 ASSIGN_FETCH_TYPE(u64, u64, 0),
219 ASSIGN_FETCH_TYPE(s8, u8, 1),
220 ASSIGN_FETCH_TYPE(s16, u16, 1),
221 ASSIGN_FETCH_TYPE(s32, u32, 1),
222 ASSIGN_FETCH_TYPE(s64, u64, 1),
223 ASSIGN_FETCH_TYPE_ALIAS(x8, u8, u8, 0),
224 ASSIGN_FETCH_TYPE_ALIAS(x16, u16, u16, 0),
225 ASSIGN_FETCH_TYPE_ALIAS(x32, u32, u32, 0),
226 ASSIGN_FETCH_TYPE_ALIAS(x64, u64, u64, 0),
227
228 ASSIGN_FETCH_TYPE_END
229 };
230
231 static inline void init_trace_uprobe_filter(struct trace_uprobe_filter *filter)
232 {
233 rwlock_init(&filter->rwlock);
234 filter->nr_systemwide = 0;
235 INIT_LIST_HEAD(&filter->perf_events);
236 }
237
238 static inline bool uprobe_filter_is_empty(struct trace_uprobe_filter *filter)
239 {
240 return !filter->nr_systemwide && list_empty(&filter->perf_events);
241 }
242
243 static inline bool is_ret_probe(struct trace_uprobe *tu)
244 {
245 return tu->consumer.ret_handler != NULL;
246 }
247
248 /*
249 * Allocate new trace_uprobe and initialize it (including uprobes).
250 */
251 static struct trace_uprobe *
252 alloc_trace_uprobe(const char *group, const char *event, int nargs, bool is_ret)
253 {
254 struct trace_uprobe *tu;
255
256 if (!event || !is_good_name(event))
257 return ERR_PTR(-EINVAL);
258
259 if (!group || !is_good_name(group))
260 return ERR_PTR(-EINVAL);
261
262 tu = kzalloc(SIZEOF_TRACE_UPROBE(nargs), GFP_KERNEL);
263 if (!tu)
264 return ERR_PTR(-ENOMEM);
265
266 tu->tp.call.class = &tu->tp.class;
267 tu->tp.call.name = kstrdup(event, GFP_KERNEL);
268 if (!tu->tp.call.name)
269 goto error;
270
271 tu->tp.class.system = kstrdup(group, GFP_KERNEL);
272 if (!tu->tp.class.system)
273 goto error;
274
275 INIT_LIST_HEAD(&tu->list);
276 INIT_LIST_HEAD(&tu->tp.files);
277 tu->consumer.handler = uprobe_dispatcher;
278 if (is_ret)
279 tu->consumer.ret_handler = uretprobe_dispatcher;
280 init_trace_uprobe_filter(&tu->filter);
281 return tu;
282
283 error:
284 kfree(tu->tp.call.name);
285 kfree(tu);
286
287 return ERR_PTR(-ENOMEM);
288 }
289
290 static void free_trace_uprobe(struct trace_uprobe *tu)
291 {
292 int i;
293
294 for (i = 0; i < tu->tp.nr_args; i++)
295 traceprobe_free_probe_arg(&tu->tp.args[i]);
296
297 iput(tu->inode);
298 kfree(tu->tp.call.class->system);
299 kfree(tu->tp.call.name);
300 kfree(tu->filename);
301 kfree(tu);
302 }
303
304 static struct trace_uprobe *find_probe_event(const char *event, const char *group)
305 {
306 struct trace_uprobe *tu;
307
308 list_for_each_entry(tu, &uprobe_list, list)
309 if (strcmp(trace_event_name(&tu->tp.call), event) == 0 &&
310 strcmp(tu->tp.call.class->system, group) == 0)
311 return tu;
312
313 return NULL;
314 }
315
316 /* Unregister a trace_uprobe and probe_event: call with locking uprobe_lock */
317 static int unregister_trace_uprobe(struct trace_uprobe *tu)
318 {
319 int ret;
320
321 ret = unregister_uprobe_event(tu);
322 if (ret)
323 return ret;
324
325 list_del(&tu->list);
326 free_trace_uprobe(tu);
327 return 0;
328 }
329
330 /* Register a trace_uprobe and probe_event */
331 static int register_trace_uprobe(struct trace_uprobe *tu)
332 {
333 struct trace_uprobe *old_tu;
334 int ret;
335
336 mutex_lock(&uprobe_lock);
337
338 /* register as an event */
339 old_tu = find_probe_event(trace_event_name(&tu->tp.call),
340 tu->tp.call.class->system);
341 if (old_tu) {
342 /* delete old event */
343 ret = unregister_trace_uprobe(old_tu);
344 if (ret)
345 goto end;
346 }
347
348 ret = register_uprobe_event(tu);
349 if (ret) {
350 pr_warn("Failed to register probe event(%d)\n", ret);
351 goto end;
352 }
353
354 list_add_tail(&tu->list, &uprobe_list);
355
356 end:
357 mutex_unlock(&uprobe_lock);
358
359 return ret;
360 }
361
362 /*
363 * Argument syntax:
364 * - Add uprobe: p|r[:[GRP/]EVENT] PATH:OFFSET [FETCHARGS]
365 *
366 * - Remove uprobe: -:[GRP/]EVENT
367 */
368 static int create_trace_uprobe(int argc, char **argv)
369 {
370 struct trace_uprobe *tu;
371 struct inode *inode;
372 char *arg, *event, *group, *filename;
373 char buf[MAX_EVENT_NAME_LEN];
374 struct path path;
375 unsigned long offset;
376 bool is_delete, is_return;
377 int i, ret;
378
379 inode = NULL;
380 ret = 0;
381 is_delete = false;
382 is_return = false;
383 event = NULL;
384 group = NULL;
385
386 /* argc must be >= 1 */
387 if (argv[0][0] == '-')
388 is_delete = true;
389 else if (argv[0][0] == 'r')
390 is_return = true;
391 else if (argv[0][0] != 'p') {
392 pr_info("Probe definition must be started with 'p', 'r' or '-'.\n");
393 return -EINVAL;
394 }
395
396 if (argv[0][1] == ':') {
397 event = &argv[0][2];
398 arg = strchr(event, '/');
399
400 if (arg) {
401 group = event;
402 event = arg + 1;
403 event[-1] = '\0';
404
405 if (strlen(group) == 0) {
406 pr_info("Group name is not specified\n");
407 return -EINVAL;
408 }
409 }
410 if (strlen(event) == 0) {
411 pr_info("Event name is not specified\n");
412 return -EINVAL;
413 }
414 }
415 if (!group)
416 group = UPROBE_EVENT_SYSTEM;
417
418 if (is_delete) {
419 int ret;
420
421 if (!event) {
422 pr_info("Delete command needs an event name.\n");
423 return -EINVAL;
424 }
425 mutex_lock(&uprobe_lock);
426 tu = find_probe_event(event, group);
427
428 if (!tu) {
429 mutex_unlock(&uprobe_lock);
430 pr_info("Event %s/%s doesn't exist.\n", group, event);
431 return -ENOENT;
432 }
433 /* delete an event */
434 ret = unregister_trace_uprobe(tu);
435 mutex_unlock(&uprobe_lock);
436 return ret;
437 }
438
439 if (argc < 2) {
440 pr_info("Probe point is not specified.\n");
441 return -EINVAL;
442 }
443 arg = strchr(argv[1], ':');
444 if (!arg) {
445 ret = -EINVAL;
446 goto fail_address_parse;
447 }
448
449 *arg++ = '\0';
450 filename = argv[1];
451 ret = kern_path(filename, LOOKUP_FOLLOW, &path);
452 if (ret)
453 goto fail_address_parse;
454
455 inode = igrab(d_inode(path.dentry));
456 path_put(&path);
457
458 if (!inode || !S_ISREG(inode->i_mode)) {
459 ret = -EINVAL;
460 goto fail_address_parse;
461 }
462
463 ret = kstrtoul(arg, 0, &offset);
464 if (ret)
465 goto fail_address_parse;
466
467 argc -= 2;
468 argv += 2;
469
470 /* setup a probe */
471 if (!event) {
472 char *tail;
473 char *ptr;
474
475 tail = kstrdup(kbasename(filename), GFP_KERNEL);
476 if (!tail) {
477 ret = -ENOMEM;
478 goto fail_address_parse;
479 }
480
481 ptr = strpbrk(tail, ".-_");
482 if (ptr)
483 *ptr = '\0';
484
485 snprintf(buf, MAX_EVENT_NAME_LEN, "%c_%s_0x%lx", 'p', tail, offset);
486 event = buf;
487 kfree(tail);
488 }
489
490 tu = alloc_trace_uprobe(group, event, argc, is_return);
491 if (IS_ERR(tu)) {
492 pr_info("Failed to allocate trace_uprobe.(%d)\n", (int)PTR_ERR(tu));
493 ret = PTR_ERR(tu);
494 goto fail_address_parse;
495 }
496 tu->offset = offset;
497 tu->inode = inode;
498 tu->filename = kstrdup(filename, GFP_KERNEL);
499
500 if (!tu->filename) {
501 pr_info("Failed to allocate filename.\n");
502 ret = -ENOMEM;
503 goto error;
504 }
505
506 /* parse arguments */
507 ret = 0;
508 for (i = 0; i < argc && i < MAX_TRACE_ARGS; i++) {
509 struct probe_arg *parg = &tu->tp.args[i];
510
511 /* Increment count for freeing args in error case */
512 tu->tp.nr_args++;
513
514 /* Parse argument name */
515 arg = strchr(argv[i], '=');
516 if (arg) {
517 *arg++ = '\0';
518 parg->name = kstrdup(argv[i], GFP_KERNEL);
519 } else {
520 arg = argv[i];
521 /* If argument name is omitted, set "argN" */
522 snprintf(buf, MAX_EVENT_NAME_LEN, "arg%d", i + 1);
523 parg->name = kstrdup(buf, GFP_KERNEL);
524 }
525
526 if (!parg->name) {
527 pr_info("Failed to allocate argument[%d] name.\n", i);
528 ret = -ENOMEM;
529 goto error;
530 }
531
532 if (!is_good_name(parg->name)) {
533 pr_info("Invalid argument[%d] name: %s\n", i, parg->name);
534 ret = -EINVAL;
535 goto error;
536 }
537
538 if (traceprobe_conflict_field_name(parg->name, tu->tp.args, i)) {
539 pr_info("Argument[%d] name '%s' conflicts with "
540 "another field.\n", i, argv[i]);
541 ret = -EINVAL;
542 goto error;
543 }
544
545 /* Parse fetch argument */
546 ret = traceprobe_parse_probe_arg(arg, &tu->tp.size, parg,
547 is_return, false,
548 uprobes_fetch_type_table);
549 if (ret) {
550 pr_info("Parse error at argument[%d]. (%d)\n", i, ret);
551 goto error;
552 }
553 }
554
555 ret = register_trace_uprobe(tu);
556 if (ret)
557 goto error;
558 return 0;
559
560 error:
561 free_trace_uprobe(tu);
562 return ret;
563
564 fail_address_parse:
565 iput(inode);
566
567 pr_info("Failed to parse address or file.\n");
568
569 return ret;
570 }
571
572 static int cleanup_all_probes(void)
573 {
574 struct trace_uprobe *tu;
575 int ret = 0;
576
577 mutex_lock(&uprobe_lock);
578 while (!list_empty(&uprobe_list)) {
579 tu = list_entry(uprobe_list.next, struct trace_uprobe, list);
580 ret = unregister_trace_uprobe(tu);
581 if (ret)
582 break;
583 }
584 mutex_unlock(&uprobe_lock);
585 return ret;
586 }
587
588 /* Probes listing interfaces */
589 static void *probes_seq_start(struct seq_file *m, loff_t *pos)
590 {
591 mutex_lock(&uprobe_lock);
592 return seq_list_start(&uprobe_list, *pos);
593 }
594
595 static void *probes_seq_next(struct seq_file *m, void *v, loff_t *pos)
596 {
597 return seq_list_next(v, &uprobe_list, pos);
598 }
599
600 static void probes_seq_stop(struct seq_file *m, void *v)
601 {
602 mutex_unlock(&uprobe_lock);
603 }
604
605 static int probes_seq_show(struct seq_file *m, void *v)
606 {
607 struct trace_uprobe *tu = v;
608 char c = is_ret_probe(tu) ? 'r' : 'p';
609 int i;
610
611 seq_printf(m, "%c:%s/%s", c, tu->tp.call.class->system,
612 trace_event_name(&tu->tp.call));
613 seq_printf(m, " %s:", tu->filename);
614
615 /* Don't print "0x (null)" when offset is 0 */
616 if (tu->offset) {
617 seq_printf(m, "0x%p", (void *)tu->offset);
618 } else {
619 switch (sizeof(void *)) {
620 case 4:
621 seq_printf(m, "0x00000000");
622 break;
623 case 8:
624 default:
625 seq_printf(m, "0x0000000000000000");
626 break;
627 }
628 }
629
630 for (i = 0; i < tu->tp.nr_args; i++)
631 seq_printf(m, " %s=%s", tu->tp.args[i].name, tu->tp.args[i].comm);
632
633 seq_putc(m, '\n');
634 return 0;
635 }
636
637 static const struct seq_operations probes_seq_op = {
638 .start = probes_seq_start,
639 .next = probes_seq_next,
640 .stop = probes_seq_stop,
641 .show = probes_seq_show
642 };
643
644 static int probes_open(struct inode *inode, struct file *file)
645 {
646 int ret;
647
648 if ((file->f_mode & FMODE_WRITE) && (file->f_flags & O_TRUNC)) {
649 ret = cleanup_all_probes();
650 if (ret)
651 return ret;
652 }
653
654 return seq_open(file, &probes_seq_op);
655 }
656
657 static ssize_t probes_write(struct file *file, const char __user *buffer,
658 size_t count, loff_t *ppos)
659 {
660 return traceprobe_probes_write(file, buffer, count, ppos, create_trace_uprobe);
661 }
662
663 static const struct file_operations uprobe_events_ops = {
664 .owner = THIS_MODULE,
665 .open = probes_open,
666 .read = seq_read,
667 .llseek = seq_lseek,
668 .release = seq_release,
669 .write = probes_write,
670 };
671
672 /* Probes profiling interfaces */
673 static int probes_profile_seq_show(struct seq_file *m, void *v)
674 {
675 struct trace_uprobe *tu = v;
676
677 seq_printf(m, " %s %-44s %15lu\n", tu->filename,
678 trace_event_name(&tu->tp.call), tu->nhit);
679 return 0;
680 }
681
682 static const struct seq_operations profile_seq_op = {
683 .start = probes_seq_start,
684 .next = probes_seq_next,
685 .stop = probes_seq_stop,
686 .show = probes_profile_seq_show
687 };
688
689 static int profile_open(struct inode *inode, struct file *file)
690 {
691 return seq_open(file, &profile_seq_op);
692 }
693
694 static const struct file_operations uprobe_profile_ops = {
695 .owner = THIS_MODULE,
696 .open = profile_open,
697 .read = seq_read,
698 .llseek = seq_lseek,
699 .release = seq_release,
700 };
701
702 struct uprobe_cpu_buffer {
703 struct mutex mutex;
704 void *buf;
705 };
706 static struct uprobe_cpu_buffer __percpu *uprobe_cpu_buffer;
707 static int uprobe_buffer_refcnt;
708
709 static int uprobe_buffer_init(void)
710 {
711 int cpu, err_cpu;
712
713 uprobe_cpu_buffer = alloc_percpu(struct uprobe_cpu_buffer);
714 if (uprobe_cpu_buffer == NULL)
715 return -ENOMEM;
716
717 for_each_possible_cpu(cpu) {
718 struct page *p = alloc_pages_node(cpu_to_node(cpu),
719 GFP_KERNEL, 0);
720 if (p == NULL) {
721 err_cpu = cpu;
722 goto err;
723 }
724 per_cpu_ptr(uprobe_cpu_buffer, cpu)->buf = page_address(p);
725 mutex_init(&per_cpu_ptr(uprobe_cpu_buffer, cpu)->mutex);
726 }
727
728 return 0;
729
730 err:
731 for_each_possible_cpu(cpu) {
732 if (cpu == err_cpu)
733 break;
734 free_page((unsigned long)per_cpu_ptr(uprobe_cpu_buffer, cpu)->buf);
735 }
736
737 free_percpu(uprobe_cpu_buffer);
738 return -ENOMEM;
739 }
740
741 static int uprobe_buffer_enable(void)
742 {
743 int ret = 0;
744
745 BUG_ON(!mutex_is_locked(&event_mutex));
746
747 if (uprobe_buffer_refcnt++ == 0) {
748 ret = uprobe_buffer_init();
749 if (ret < 0)
750 uprobe_buffer_refcnt--;
751 }
752
753 return ret;
754 }
755
756 static void uprobe_buffer_disable(void)
757 {
758 int cpu;
759
760 BUG_ON(!mutex_is_locked(&event_mutex));
761
762 if (--uprobe_buffer_refcnt == 0) {
763 for_each_possible_cpu(cpu)
764 free_page((unsigned long)per_cpu_ptr(uprobe_cpu_buffer,
765 cpu)->buf);
766
767 free_percpu(uprobe_cpu_buffer);
768 uprobe_cpu_buffer = NULL;
769 }
770 }
771
772 static struct uprobe_cpu_buffer *uprobe_buffer_get(void)
773 {
774 struct uprobe_cpu_buffer *ucb;
775 int cpu;
776
777 cpu = raw_smp_processor_id();
778 ucb = per_cpu_ptr(uprobe_cpu_buffer, cpu);
779
780 /*
781 * Use per-cpu buffers for fastest access, but we might migrate
782 * so the mutex makes sure we have sole access to it.
783 */
784 mutex_lock(&ucb->mutex);
785
786 return ucb;
787 }
788
789 static void uprobe_buffer_put(struct uprobe_cpu_buffer *ucb)
790 {
791 mutex_unlock(&ucb->mutex);
792 }
793
794 static void __uprobe_trace_func(struct trace_uprobe *tu,
795 unsigned long func, struct pt_regs *regs,
796 struct uprobe_cpu_buffer *ucb, int dsize,
797 struct trace_event_file *trace_file)
798 {
799 struct uprobe_trace_entry_head *entry;
800 struct ring_buffer_event *event;
801 struct ring_buffer *buffer;
802 void *data;
803 int size, esize;
804 struct trace_event_call *call = &tu->tp.call;
805
806 WARN_ON(call != trace_file->event_call);
807
808 if (WARN_ON_ONCE(tu->tp.size + dsize > PAGE_SIZE))
809 return;
810
811 if (trace_trigger_soft_disabled(trace_file))
812 return;
813
814 esize = SIZEOF_TRACE_ENTRY(is_ret_probe(tu));
815 size = esize + tu->tp.size + dsize;
816 event = trace_event_buffer_lock_reserve(&buffer, trace_file,
817 call->event.type, size, 0, 0);
818 if (!event)
819 return;
820
821 entry = ring_buffer_event_data(event);
822 if (is_ret_probe(tu)) {
823 entry->vaddr[0] = func;
824 entry->vaddr[1] = instruction_pointer(regs);
825 data = DATAOF_TRACE_ENTRY(entry, true);
826 } else {
827 entry->vaddr[0] = instruction_pointer(regs);
828 data = DATAOF_TRACE_ENTRY(entry, false);
829 }
830
831 memcpy(data, ucb->buf, tu->tp.size + dsize);
832
833 event_trigger_unlock_commit(trace_file, buffer, event, entry, 0, 0);
834 }
835
836 /* uprobe handler */
837 static int uprobe_trace_func(struct trace_uprobe *tu, struct pt_regs *regs,
838 struct uprobe_cpu_buffer *ucb, int dsize)
839 {
840 struct event_file_link *link;
841
842 if (is_ret_probe(tu))
843 return 0;
844
845 rcu_read_lock();
846 list_for_each_entry_rcu(link, &tu->tp.files, list)
847 __uprobe_trace_func(tu, 0, regs, ucb, dsize, link->file);
848 rcu_read_unlock();
849
850 return 0;
851 }
852
853 static void uretprobe_trace_func(struct trace_uprobe *tu, unsigned long func,
854 struct pt_regs *regs,
855 struct uprobe_cpu_buffer *ucb, int dsize)
856 {
857 struct event_file_link *link;
858
859 rcu_read_lock();
860 list_for_each_entry_rcu(link, &tu->tp.files, list)
861 __uprobe_trace_func(tu, func, regs, ucb, dsize, link->file);
862 rcu_read_unlock();
863 }
864
865 /* Event entry printers */
866 static enum print_line_t
867 print_uprobe_event(struct trace_iterator *iter, int flags, struct trace_event *event)
868 {
869 struct uprobe_trace_entry_head *entry;
870 struct trace_seq *s = &iter->seq;
871 struct trace_uprobe *tu;
872 u8 *data;
873 int i;
874
875 entry = (struct uprobe_trace_entry_head *)iter->ent;
876 tu = container_of(event, struct trace_uprobe, tp.call.event);
877
878 if (is_ret_probe(tu)) {
879 trace_seq_printf(s, "%s: (0x%lx <- 0x%lx)",
880 trace_event_name(&tu->tp.call),
881 entry->vaddr[1], entry->vaddr[0]);
882 data = DATAOF_TRACE_ENTRY(entry, true);
883 } else {
884 trace_seq_printf(s, "%s: (0x%lx)",
885 trace_event_name(&tu->tp.call),
886 entry->vaddr[0]);
887 data = DATAOF_TRACE_ENTRY(entry, false);
888 }
889
890 for (i = 0; i < tu->tp.nr_args; i++) {
891 struct probe_arg *parg = &tu->tp.args[i];
892
893 if (!parg->type->print(s, parg->name, data + parg->offset, entry))
894 goto out;
895 }
896
897 trace_seq_putc(s, '\n');
898
899 out:
900 return trace_handle_return(s);
901 }
902
903 typedef bool (*filter_func_t)(struct uprobe_consumer *self,
904 enum uprobe_filter_ctx ctx,
905 struct mm_struct *mm);
906
907 static int
908 probe_event_enable(struct trace_uprobe *tu, struct trace_event_file *file,
909 filter_func_t filter)
910 {
911 bool enabled = trace_probe_is_enabled(&tu->tp);
912 struct event_file_link *link = NULL;
913 int ret;
914
915 if (file) {
916 if (tu->tp.flags & TP_FLAG_PROFILE)
917 return -EINTR;
918
919 link = kmalloc(sizeof(*link), GFP_KERNEL);
920 if (!link)
921 return -ENOMEM;
922
923 link->file = file;
924 list_add_tail_rcu(&link->list, &tu->tp.files);
925
926 tu->tp.flags |= TP_FLAG_TRACE;
927 } else {
928 if (tu->tp.flags & TP_FLAG_TRACE)
929 return -EINTR;
930
931 tu->tp.flags |= TP_FLAG_PROFILE;
932 }
933
934 WARN_ON(!uprobe_filter_is_empty(&tu->filter));
935
936 if (enabled)
937 return 0;
938
939 ret = uprobe_buffer_enable();
940 if (ret)
941 goto err_flags;
942
943 tu->consumer.filter = filter;
944 ret = uprobe_register(tu->inode, tu->offset, &tu->consumer);
945 if (ret)
946 goto err_buffer;
947
948 return 0;
949
950 err_buffer:
951 uprobe_buffer_disable();
952
953 err_flags:
954 if (file) {
955 list_del(&link->list);
956 kfree(link);
957 tu->tp.flags &= ~TP_FLAG_TRACE;
958 } else {
959 tu->tp.flags &= ~TP_FLAG_PROFILE;
960 }
961 return ret;
962 }
963
964 static void
965 probe_event_disable(struct trace_uprobe *tu, struct trace_event_file *file)
966 {
967 if (!trace_probe_is_enabled(&tu->tp))
968 return;
969
970 if (file) {
971 struct event_file_link *link;
972
973 link = find_event_file_link(&tu->tp, file);
974 if (!link)
975 return;
976
977 list_del_rcu(&link->list);
978 /* synchronize with u{,ret}probe_trace_func */
979 synchronize_rcu();
980 kfree(link);
981
982 if (!list_empty(&tu->tp.files))
983 return;
984 }
985
986 WARN_ON(!uprobe_filter_is_empty(&tu->filter));
987
988 uprobe_unregister(tu->inode, tu->offset, &tu->consumer);
989 tu->tp.flags &= file ? ~TP_FLAG_TRACE : ~TP_FLAG_PROFILE;
990
991 uprobe_buffer_disable();
992 }
993
994 static int uprobe_event_define_fields(struct trace_event_call *event_call)
995 {
996 int ret, i, size;
997 struct uprobe_trace_entry_head field;
998 struct trace_uprobe *tu = event_call->data;
999
1000 if (is_ret_probe(tu)) {
1001 DEFINE_FIELD(unsigned long, vaddr[0], FIELD_STRING_FUNC, 0);
1002 DEFINE_FIELD(unsigned long, vaddr[1], FIELD_STRING_RETIP, 0);
1003 size = SIZEOF_TRACE_ENTRY(true);
1004 } else {
1005 DEFINE_FIELD(unsigned long, vaddr[0], FIELD_STRING_IP, 0);
1006 size = SIZEOF_TRACE_ENTRY(false);
1007 }
1008 /* Set argument names as fields */
1009 for (i = 0; i < tu->tp.nr_args; i++) {
1010 struct probe_arg *parg = &tu->tp.args[i];
1011
1012 ret = trace_define_field(event_call, parg->type->fmttype,
1013 parg->name, size + parg->offset,
1014 parg->type->size, parg->type->is_signed,
1015 FILTER_OTHER);
1016
1017 if (ret)
1018 return ret;
1019 }
1020 return 0;
1021 }
1022
1023 #ifdef CONFIG_PERF_EVENTS
1024 static bool
1025 __uprobe_perf_filter(struct trace_uprobe_filter *filter, struct mm_struct *mm)
1026 {
1027 struct perf_event *event;
1028
1029 if (filter->nr_systemwide)
1030 return true;
1031
1032 list_for_each_entry(event, &filter->perf_events, hw.tp_list) {
1033 if (event->hw.target->mm == mm)
1034 return true;
1035 }
1036
1037 return false;
1038 }
1039
1040 static inline bool
1041 uprobe_filter_event(struct trace_uprobe *tu, struct perf_event *event)
1042 {
1043 return __uprobe_perf_filter(&tu->filter, event->hw.target->mm);
1044 }
1045
1046 static int uprobe_perf_close(struct trace_uprobe *tu, struct perf_event *event)
1047 {
1048 bool done;
1049
1050 write_lock(&tu->filter.rwlock);
1051 if (event->hw.target) {
1052 list_del(&event->hw.tp_list);
1053 done = tu->filter.nr_systemwide ||
1054 (event->hw.target->flags & PF_EXITING) ||
1055 uprobe_filter_event(tu, event);
1056 } else {
1057 tu->filter.nr_systemwide--;
1058 done = tu->filter.nr_systemwide;
1059 }
1060 write_unlock(&tu->filter.rwlock);
1061
1062 if (!done)
1063 return uprobe_apply(tu->inode, tu->offset, &tu->consumer, false);
1064
1065 return 0;
1066 }
1067
1068 static int uprobe_perf_open(struct trace_uprobe *tu, struct perf_event *event)
1069 {
1070 bool done;
1071 int err;
1072
1073 write_lock(&tu->filter.rwlock);
1074 if (event->hw.target) {
1075 /*
1076 * event->parent != NULL means copy_process(), we can avoid
1077 * uprobe_apply(). current->mm must be probed and we can rely
1078 * on dup_mmap() which preserves the already installed bp's.
1079 *
1080 * attr.enable_on_exec means that exec/mmap will install the
1081 * breakpoints we need.
1082 */
1083 done = tu->filter.nr_systemwide ||
1084 event->parent || event->attr.enable_on_exec ||
1085 uprobe_filter_event(tu, event);
1086 list_add(&event->hw.tp_list, &tu->filter.perf_events);
1087 } else {
1088 done = tu->filter.nr_systemwide;
1089 tu->filter.nr_systemwide++;
1090 }
1091 write_unlock(&tu->filter.rwlock);
1092
1093 err = 0;
1094 if (!done) {
1095 err = uprobe_apply(tu->inode, tu->offset, &tu->consumer, true);
1096 if (err)
1097 uprobe_perf_close(tu, event);
1098 }
1099 return err;
1100 }
1101
1102 static bool uprobe_perf_filter(struct uprobe_consumer *uc,
1103 enum uprobe_filter_ctx ctx, struct mm_struct *mm)
1104 {
1105 struct trace_uprobe *tu;
1106 int ret;
1107
1108 tu = container_of(uc, struct trace_uprobe, consumer);
1109 read_lock(&tu->filter.rwlock);
1110 ret = __uprobe_perf_filter(&tu->filter, mm);
1111 read_unlock(&tu->filter.rwlock);
1112
1113 return ret;
1114 }
1115
1116 static void __uprobe_perf_func(struct trace_uprobe *tu,
1117 unsigned long func, struct pt_regs *regs,
1118 struct uprobe_cpu_buffer *ucb, int dsize)
1119 {
1120 struct trace_event_call *call = &tu->tp.call;
1121 struct uprobe_trace_entry_head *entry;
1122 struct bpf_prog *prog = call->prog;
1123 struct hlist_head *head;
1124 void *data;
1125 int size, esize;
1126 int rctx;
1127
1128 if (prog && !trace_call_bpf(prog, regs))
1129 return;
1130
1131 esize = SIZEOF_TRACE_ENTRY(is_ret_probe(tu));
1132
1133 size = esize + tu->tp.size + dsize;
1134 size = ALIGN(size + sizeof(u32), sizeof(u64)) - sizeof(u32);
1135 if (WARN_ONCE(size > PERF_MAX_TRACE_SIZE, "profile buffer not large enough"))
1136 return;
1137
1138 preempt_disable();
1139 head = this_cpu_ptr(call->perf_events);
1140 if (hlist_empty(head))
1141 goto out;
1142
1143 entry = perf_trace_buf_alloc(size, NULL, &rctx);
1144 if (!entry)
1145 goto out;
1146
1147 if (is_ret_probe(tu)) {
1148 entry->vaddr[0] = func;
1149 entry->vaddr[1] = instruction_pointer(regs);
1150 data = DATAOF_TRACE_ENTRY(entry, true);
1151 } else {
1152 entry->vaddr[0] = instruction_pointer(regs);
1153 data = DATAOF_TRACE_ENTRY(entry, false);
1154 }
1155
1156 memcpy(data, ucb->buf, tu->tp.size + dsize);
1157
1158 if (size - esize > tu->tp.size + dsize) {
1159 int len = tu->tp.size + dsize;
1160
1161 memset(data + len, 0, size - esize - len);
1162 }
1163
1164 perf_trace_buf_submit(entry, size, rctx, call->event.type, 1, regs,
1165 head, NULL);
1166 out:
1167 preempt_enable();
1168 }
1169
1170 /* uprobe profile handler */
1171 static int uprobe_perf_func(struct trace_uprobe *tu, struct pt_regs *regs,
1172 struct uprobe_cpu_buffer *ucb, int dsize)
1173 {
1174 if (!uprobe_perf_filter(&tu->consumer, 0, current->mm))
1175 return UPROBE_HANDLER_REMOVE;
1176
1177 if (!is_ret_probe(tu))
1178 __uprobe_perf_func(tu, 0, regs, ucb, dsize);
1179 return 0;
1180 }
1181
1182 static void uretprobe_perf_func(struct trace_uprobe *tu, unsigned long func,
1183 struct pt_regs *regs,
1184 struct uprobe_cpu_buffer *ucb, int dsize)
1185 {
1186 __uprobe_perf_func(tu, func, regs, ucb, dsize);
1187 }
1188 #endif /* CONFIG_PERF_EVENTS */
1189
1190 static int
1191 trace_uprobe_register(struct trace_event_call *event, enum trace_reg type,
1192 void *data)
1193 {
1194 struct trace_uprobe *tu = event->data;
1195 struct trace_event_file *file = data;
1196
1197 switch (type) {
1198 case TRACE_REG_REGISTER:
1199 return probe_event_enable(tu, file, NULL);
1200
1201 case TRACE_REG_UNREGISTER:
1202 probe_event_disable(tu, file);
1203 return 0;
1204
1205 #ifdef CONFIG_PERF_EVENTS
1206 case TRACE_REG_PERF_REGISTER:
1207 return probe_event_enable(tu, NULL, uprobe_perf_filter);
1208
1209 case TRACE_REG_PERF_UNREGISTER:
1210 probe_event_disable(tu, NULL);
1211 return 0;
1212
1213 case TRACE_REG_PERF_OPEN:
1214 return uprobe_perf_open(tu, data);
1215
1216 case TRACE_REG_PERF_CLOSE:
1217 return uprobe_perf_close(tu, data);
1218
1219 #endif
1220 default:
1221 return 0;
1222 }
1223 return 0;
1224 }
1225
1226 static int uprobe_dispatcher(struct uprobe_consumer *con, struct pt_regs *regs)
1227 {
1228 struct trace_uprobe *tu;
1229 struct uprobe_dispatch_data udd;
1230 struct uprobe_cpu_buffer *ucb;
1231 int dsize, esize;
1232 int ret = 0;
1233
1234
1235 tu = container_of(con, struct trace_uprobe, consumer);
1236 tu->nhit++;
1237
1238 udd.tu = tu;
1239 udd.bp_addr = instruction_pointer(regs);
1240
1241 current->utask->vaddr = (unsigned long) &udd;
1242
1243 if (WARN_ON_ONCE(!uprobe_cpu_buffer))
1244 return 0;
1245
1246 dsize = __get_data_size(&tu->tp, regs);
1247 esize = SIZEOF_TRACE_ENTRY(is_ret_probe(tu));
1248
1249 ucb = uprobe_buffer_get();
1250 store_trace_args(esize, &tu->tp, regs, ucb->buf, dsize);
1251
1252 if (tu->tp.flags & TP_FLAG_TRACE)
1253 ret |= uprobe_trace_func(tu, regs, ucb, dsize);
1254
1255 #ifdef CONFIG_PERF_EVENTS
1256 if (tu->tp.flags & TP_FLAG_PROFILE)
1257 ret |= uprobe_perf_func(tu, regs, ucb, dsize);
1258 #endif
1259 uprobe_buffer_put(ucb);
1260 return ret;
1261 }
1262
1263 static int uretprobe_dispatcher(struct uprobe_consumer *con,
1264 unsigned long func, struct pt_regs *regs)
1265 {
1266 struct trace_uprobe *tu;
1267 struct uprobe_dispatch_data udd;
1268 struct uprobe_cpu_buffer *ucb;
1269 int dsize, esize;
1270
1271 tu = container_of(con, struct trace_uprobe, consumer);
1272
1273 udd.tu = tu;
1274 udd.bp_addr = func;
1275
1276 current->utask->vaddr = (unsigned long) &udd;
1277
1278 if (WARN_ON_ONCE(!uprobe_cpu_buffer))
1279 return 0;
1280
1281 dsize = __get_data_size(&tu->tp, regs);
1282 esize = SIZEOF_TRACE_ENTRY(is_ret_probe(tu));
1283
1284 ucb = uprobe_buffer_get();
1285 store_trace_args(esize, &tu->tp, regs, ucb->buf, dsize);
1286
1287 if (tu->tp.flags & TP_FLAG_TRACE)
1288 uretprobe_trace_func(tu, func, regs, ucb, dsize);
1289
1290 #ifdef CONFIG_PERF_EVENTS
1291 if (tu->tp.flags & TP_FLAG_PROFILE)
1292 uretprobe_perf_func(tu, func, regs, ucb, dsize);
1293 #endif
1294 uprobe_buffer_put(ucb);
1295 return 0;
1296 }
1297
1298 static struct trace_event_functions uprobe_funcs = {
1299 .trace = print_uprobe_event
1300 };
1301
1302 static int register_uprobe_event(struct trace_uprobe *tu)
1303 {
1304 struct trace_event_call *call = &tu->tp.call;
1305 int ret;
1306
1307 /* Initialize trace_event_call */
1308 INIT_LIST_HEAD(&call->class->fields);
1309 call->event.funcs = &uprobe_funcs;
1310 call->class->define_fields = uprobe_event_define_fields;
1311
1312 if (set_print_fmt(&tu->tp, is_ret_probe(tu)) < 0)
1313 return -ENOMEM;
1314
1315 ret = register_trace_event(&call->event);
1316 if (!ret) {
1317 kfree(call->print_fmt);
1318 return -ENODEV;
1319 }
1320
1321 call->flags = TRACE_EVENT_FL_UPROBE;
1322 call->class->reg = trace_uprobe_register;
1323 call->data = tu;
1324 ret = trace_add_event_call(call);
1325
1326 if (ret) {
1327 pr_info("Failed to register uprobe event: %s\n",
1328 trace_event_name(call));
1329 kfree(call->print_fmt);
1330 unregister_trace_event(&call->event);
1331 }
1332
1333 return ret;
1334 }
1335
1336 static int unregister_uprobe_event(struct trace_uprobe *tu)
1337 {
1338 int ret;
1339
1340 /* tu->event is unregistered in trace_remove_event_call() */
1341 ret = trace_remove_event_call(&tu->tp.call);
1342 if (ret)
1343 return ret;
1344 kfree(tu->tp.call.print_fmt);
1345 tu->tp.call.print_fmt = NULL;
1346 return 0;
1347 }
1348
1349 /* Make a trace interface for controling probe points */
1350 static __init int init_uprobe_trace(void)
1351 {
1352 struct dentry *d_tracer;
1353
1354 d_tracer = tracing_init_dentry();
1355 if (IS_ERR(d_tracer))
1356 return 0;
1357
1358 trace_create_file("uprobe_events", 0644, d_tracer,
1359 NULL, &uprobe_events_ops);
1360 /* Profile interface */
1361 trace_create_file("uprobe_profile", 0444, d_tracer,
1362 NULL, &uprobe_profile_ops);
1363 return 0;
1364 }
1365
1366 fs_initcall(init_uprobe_trace);
Linux with added FPC-III support