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signal/openrisc: Fix do_unaligned_access to send the proper signal
[linux/fpc-iii.git] / kernel / trace / trace_uprobe.c
blob40592e7b3568bcfd41220f579fc05066e3675b33
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 #define pr_fmt(fmt) "trace_kprobe: " fmt
21
22 #include <linux/module.h>
23 #include <linux/uaccess.h>
24 #include <linux/uprobes.h>
25 #include <linux/namei.h>
26 #include <linux/string.h>
27 #include <linux/rculist.h>
28
29 #include "trace_probe.h"
30
31 #define UPROBE_EVENT_SYSTEM "uprobes"
32
33 struct uprobe_trace_entry_head {
34 struct trace_entry ent;
35 unsigned long vaddr[];
36 };
37
38 #define SIZEOF_TRACE_ENTRY(is_return) \
39 (sizeof(struct uprobe_trace_entry_head) + \
40 sizeof(unsigned long) * (is_return ? 2 : 1))
41
42 #define DATAOF_TRACE_ENTRY(entry, is_return) \
43 ((void*)(entry) + SIZEOF_TRACE_ENTRY(is_return))
44
45 struct trace_uprobe_filter {
46 rwlock_t rwlock;
47 int nr_systemwide;
48 struct list_head perf_events;
49 };
50
51 /*
52 * uprobe event core functions
53 */
54 struct trace_uprobe {
55 struct list_head list;
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 struct trace_probe tp;
63 };
64
65 #define SIZEOF_TRACE_UPROBE(n) \
66 (offsetof(struct trace_uprobe, tp.args) + \
67 (sizeof(struct probe_arg) * (n)))
68
69 static int register_uprobe_event(struct trace_uprobe *tu);
70 static int unregister_uprobe_event(struct trace_uprobe *tu);
71
72 static DEFINE_MUTEX(uprobe_lock);
73 static LIST_HEAD(uprobe_list);
74
75 struct uprobe_dispatch_data {
76 struct trace_uprobe *tu;
77 unsigned long bp_addr;
78 };
79
80 static int uprobe_dispatcher(struct uprobe_consumer *con, struct pt_regs *regs);
81 static int uretprobe_dispatcher(struct uprobe_consumer *con,
82 unsigned long func, struct pt_regs *regs);
83
84 #ifdef CONFIG_STACK_GROWSUP
85 static unsigned long adjust_stack_addr(unsigned long addr, unsigned int n)
86 {
87 return addr - (n * sizeof(long));
88 }
89 #else
90 static unsigned long adjust_stack_addr(unsigned long addr, unsigned int n)
91 {
92 return addr + (n * sizeof(long));
93 }
94 #endif
95
96 static unsigned long get_user_stack_nth(struct pt_regs *regs, unsigned int n)
97 {
98 unsigned long ret;
99 unsigned long addr = user_stack_pointer(regs);
100
101 addr = adjust_stack_addr(addr, n);
102
103 if (copy_from_user(&ret, (void __force __user *) addr, sizeof(ret)))
104 return 0;
105
106 return ret;
107 }
108
109 /*
110 * Uprobes-specific fetch functions
111 */
112 #define DEFINE_FETCH_stack(type) \
113 static void FETCH_FUNC_NAME(stack, type)(struct pt_regs *regs, \
114 void *offset, void *dest) \
115 { \
116 *(type *)dest = (type)get_user_stack_nth(regs, \
117 ((unsigned long)offset)); \
118 }
119 DEFINE_BASIC_FETCH_FUNCS(stack)
120 /* No string on the stack entry */
121 #define fetch_stack_string NULL
122 #define fetch_stack_string_size NULL
123
124 #define DEFINE_FETCH_memory(type) \
125 static void FETCH_FUNC_NAME(memory, type)(struct pt_regs *regs, \
126 void *addr, void *dest) \
127 { \
128 type retval; \
129 void __user *vaddr = (void __force __user *) addr; \
130 \
131 if (copy_from_user(&retval, vaddr, sizeof(type))) \
132 *(type *)dest = 0; \
133 else \
134 *(type *) dest = retval; \
135 }
136 DEFINE_BASIC_FETCH_FUNCS(memory)
137 /*
138 * Fetch a null-terminated string. Caller MUST set *(u32 *)dest with max
139 * length and relative data location.
140 */
141 static void FETCH_FUNC_NAME(memory, string)(struct pt_regs *regs,
142 void *addr, void *dest)
143 {
144 long ret;
145 u32 rloc = *(u32 *)dest;
146 int maxlen = get_rloc_len(rloc);
147 u8 *dst = get_rloc_data(dest);
148 void __user *src = (void __force __user *) addr;
149
150 if (!maxlen)
151 return;
152
153 ret = strncpy_from_user(dst, src, maxlen);
154
155 if (ret < 0) { /* Failed to fetch string */
156 ((u8 *)get_rloc_data(dest))[0] = '\0';
157 *(u32 *)dest = make_data_rloc(0, get_rloc_offs(rloc));
158 } else {
159 *(u32 *)dest = make_data_rloc(ret, get_rloc_offs(rloc));
160 }
161 }
162
163 static void FETCH_FUNC_NAME(memory, string_size)(struct pt_regs *regs,
164 void *addr, void *dest)
165 {
166 int len;
167 void __user *vaddr = (void __force __user *) addr;
168
169 len = strnlen_user(vaddr, MAX_STRING_SIZE);
170
171 if (len == 0 || len > MAX_STRING_SIZE) /* Failed to check length */
172 *(u32 *)dest = 0;
173 else
174 *(u32 *)dest = len;
175 }
176
177 static unsigned long translate_user_vaddr(void *file_offset)
178 {
179 unsigned long base_addr;
180 struct uprobe_dispatch_data *udd;
181
182 udd = (void *) current->utask->vaddr;
183
184 base_addr = udd->bp_addr - udd->tu->offset;
185 return base_addr + (unsigned long)file_offset;
186 }
187
188 #define DEFINE_FETCH_file_offset(type) \
189 static void FETCH_FUNC_NAME(file_offset, type)(struct pt_regs *regs, \
190 void *offset, void *dest)\
191 { \
192 void *vaddr = (void *)translate_user_vaddr(offset); \
193 \
194 FETCH_FUNC_NAME(memory, type)(regs, vaddr, dest); \
195 }
196 DEFINE_BASIC_FETCH_FUNCS(file_offset)
197 DEFINE_FETCH_file_offset(string)
198 DEFINE_FETCH_file_offset(string_size)
199
200 /* Fetch type information table */
201 static const struct fetch_type uprobes_fetch_type_table[] = {
202 /* Special types */
203 [FETCH_TYPE_STRING] = __ASSIGN_FETCH_TYPE("string", string, string,
204 sizeof(u32), 1, "__data_loc char[]"),
205 [FETCH_TYPE_STRSIZE] = __ASSIGN_FETCH_TYPE("string_size", u32,
206 string_size, sizeof(u32), 0, "u32"),
207 /* Basic types */
208 ASSIGN_FETCH_TYPE(u8, u8, 0),
209 ASSIGN_FETCH_TYPE(u16, u16, 0),
210 ASSIGN_FETCH_TYPE(u32, u32, 0),
211 ASSIGN_FETCH_TYPE(u64, u64, 0),
212 ASSIGN_FETCH_TYPE(s8, u8, 1),
213 ASSIGN_FETCH_TYPE(s16, u16, 1),
214 ASSIGN_FETCH_TYPE(s32, u32, 1),
215 ASSIGN_FETCH_TYPE(s64, u64, 1),
216 ASSIGN_FETCH_TYPE_ALIAS(x8, u8, u8, 0),
217 ASSIGN_FETCH_TYPE_ALIAS(x16, u16, u16, 0),
218 ASSIGN_FETCH_TYPE_ALIAS(x32, u32, u32, 0),
219 ASSIGN_FETCH_TYPE_ALIAS(x64, u64, u64, 0),
220
221 ASSIGN_FETCH_TYPE_END
222 };
223
224 static inline void init_trace_uprobe_filter(struct trace_uprobe_filter *filter)
225 {
226 rwlock_init(&filter->rwlock);
227 filter->nr_systemwide = 0;
228 INIT_LIST_HEAD(&filter->perf_events);
229 }
230
231 static inline bool uprobe_filter_is_empty(struct trace_uprobe_filter *filter)
232 {
233 return !filter->nr_systemwide && list_empty(&filter->perf_events);
234 }
235
236 static inline bool is_ret_probe(struct trace_uprobe *tu)
237 {
238 return tu->consumer.ret_handler != NULL;
239 }
240
241 /*
242 * Allocate new trace_uprobe and initialize it (including uprobes).
243 */
244 static struct trace_uprobe *
245 alloc_trace_uprobe(const char *group, const char *event, int nargs, bool is_ret)
246 {
247 struct trace_uprobe *tu;
248
249 if (!event || !is_good_name(event))
250 return ERR_PTR(-EINVAL);
251
252 if (!group || !is_good_name(group))
253 return ERR_PTR(-EINVAL);
254
255 tu = kzalloc(SIZEOF_TRACE_UPROBE(nargs), GFP_KERNEL);
256 if (!tu)
257 return ERR_PTR(-ENOMEM);
258
259 tu->tp.call.class = &tu->tp.class;
260 tu->tp.call.name = kstrdup(event, GFP_KERNEL);
261 if (!tu->tp.call.name)
262 goto error;
263
264 tu->tp.class.system = kstrdup(group, GFP_KERNEL);
265 if (!tu->tp.class.system)
266 goto error;
267
268 INIT_LIST_HEAD(&tu->list);
269 INIT_LIST_HEAD(&tu->tp.files);
270 tu->consumer.handler = uprobe_dispatcher;
271 if (is_ret)
272 tu->consumer.ret_handler = uretprobe_dispatcher;
273 init_trace_uprobe_filter(&tu->filter);
274 return tu;
275
276 error:
277 kfree(tu->tp.call.name);
278 kfree(tu);
279
280 return ERR_PTR(-ENOMEM);
281 }
282
283 static void free_trace_uprobe(struct trace_uprobe *tu)
284 {
285 int i;
286
287 for (i = 0; i < tu->tp.nr_args; i++)
288 traceprobe_free_probe_arg(&tu->tp.args[i]);
289
290 iput(tu->inode);
291 kfree(tu->tp.call.class->system);
292 kfree(tu->tp.call.name);
293 kfree(tu->filename);
294 kfree(tu);
295 }
296
297 static struct trace_uprobe *find_probe_event(const char *event, const char *group)
298 {
299 struct trace_uprobe *tu;
300
301 list_for_each_entry(tu, &uprobe_list, list)
302 if (strcmp(trace_event_name(&tu->tp.call), event) == 0 &&
303 strcmp(tu->tp.call.class->system, group) == 0)
304 return tu;
305
306 return NULL;
307 }
308
309 /* Unregister a trace_uprobe and probe_event: call with locking uprobe_lock */
310 static int unregister_trace_uprobe(struct trace_uprobe *tu)
311 {
312 int ret;
313
314 ret = unregister_uprobe_event(tu);
315 if (ret)
316 return ret;
317
318 list_del(&tu->list);
319 free_trace_uprobe(tu);
320 return 0;
321 }
322
323 /* Register a trace_uprobe and probe_event */
324 static int register_trace_uprobe(struct trace_uprobe *tu)
325 {
326 struct trace_uprobe *old_tu;
327 int ret;
328
329 mutex_lock(&uprobe_lock);
330
331 /* register as an event */
332 old_tu = find_probe_event(trace_event_name(&tu->tp.call),
333 tu->tp.call.class->system);
334 if (old_tu) {
335 /* delete old event */
336 ret = unregister_trace_uprobe(old_tu);
337 if (ret)
338 goto end;
339 }
340
341 ret = register_uprobe_event(tu);
342 if (ret) {
343 pr_warn("Failed to register probe event(%d)\n", ret);
344 goto end;
345 }
346
347 list_add_tail(&tu->list, &uprobe_list);
348
349 end:
350 mutex_unlock(&uprobe_lock);
351
352 return ret;
353 }
354
355 /*
356 * Argument syntax:
357 * - Add uprobe: p|r[:[GRP/]EVENT] PATH:OFFSET [FETCHARGS]
358 *
359 * - Remove uprobe: -:[GRP/]EVENT
360 */
361 static int create_trace_uprobe(int argc, char **argv)
362 {
363 struct trace_uprobe *tu;
364 struct inode *inode;
365 char *arg, *event, *group, *filename;
366 char buf[MAX_EVENT_NAME_LEN];
367 struct path path;
368 unsigned long offset;
369 bool is_delete, is_return;
370 int i, ret;
371
372 inode = NULL;
373 ret = 0;
374 is_delete = false;
375 is_return = false;
376 event = NULL;
377 group = NULL;
378
379 /* argc must be >= 1 */
380 if (argv[0][0] == '-')
381 is_delete = true;
382 else if (argv[0][0] == 'r')
383 is_return = true;
384 else if (argv[0][0] != 'p') {
385 pr_info("Probe definition must be started with 'p', 'r' or '-'.\n");
386 return -EINVAL;
387 }
388
389 if (argv[0][1] == ':') {
390 event = &argv[0][2];
391 arg = strchr(event, '/');
392
393 if (arg) {
394 group = event;
395 event = arg + 1;
396 event[-1] = '\0';
397
398 if (strlen(group) == 0) {
399 pr_info("Group name is not specified\n");
400 return -EINVAL;
401 }
402 }
403 if (strlen(event) == 0) {
404 pr_info("Event name is not specified\n");
405 return -EINVAL;
406 }
407 }
408 if (!group)
409 group = UPROBE_EVENT_SYSTEM;
410
411 if (is_delete) {
412 int ret;
413
414 if (!event) {
415 pr_info("Delete command needs an event name.\n");
416 return -EINVAL;
417 }
418 mutex_lock(&uprobe_lock);
419 tu = find_probe_event(event, group);
420
421 if (!tu) {
422 mutex_unlock(&uprobe_lock);
423 pr_info("Event %s/%s doesn't exist.\n", group, event);
424 return -ENOENT;
425 }
426 /* delete an event */
427 ret = unregister_trace_uprobe(tu);
428 mutex_unlock(&uprobe_lock);
429 return ret;
430 }
431
432 if (argc < 2) {
433 pr_info("Probe point is not specified.\n");
434 return -EINVAL;
435 }
436 /* Find the last occurrence, in case the path contains ':' too. */
437 arg = strrchr(argv[1], ':');
438 if (!arg) {
439 ret = -EINVAL;
440 goto fail_address_parse;
441 }
442
443 *arg++ = '\0';
444 filename = argv[1];
445 ret = kern_path(filename, LOOKUP_FOLLOW, &path);
446 if (ret)
447 goto fail_address_parse;
448
449 inode = igrab(d_inode(path.dentry));
450 path_put(&path);
451
452 if (!inode || !S_ISREG(inode->i_mode)) {
453 ret = -EINVAL;
454 goto fail_address_parse;
455 }
456
457 ret = kstrtoul(arg, 0, &offset);
458 if (ret)
459 goto fail_address_parse;
460
461 argc -= 2;
462 argv += 2;
463
464 /* setup a probe */
465 if (!event) {
466 char *tail;
467 char *ptr;
468
469 tail = kstrdup(kbasename(filename), GFP_KERNEL);
470 if (!tail) {
471 ret = -ENOMEM;
472 goto fail_address_parse;
473 }
474
475 ptr = strpbrk(tail, ".-_");
476 if (ptr)
477 *ptr = '\0';
478
479 snprintf(buf, MAX_EVENT_NAME_LEN, "%c_%s_0x%lx", 'p', tail, offset);
480 event = buf;
481 kfree(tail);
482 }
483
484 tu = alloc_trace_uprobe(group, event, argc, is_return);
485 if (IS_ERR(tu)) {
486 pr_info("Failed to allocate trace_uprobe.(%d)\n", (int)PTR_ERR(tu));
487 ret = PTR_ERR(tu);
488 goto fail_address_parse;
489 }
490 tu->offset = offset;
491 tu->inode = inode;
492 tu->filename = kstrdup(filename, GFP_KERNEL);
493
494 if (!tu->filename) {
495 pr_info("Failed to allocate filename.\n");
496 ret = -ENOMEM;
497 goto error;
498 }
499
500 /* parse arguments */
501 ret = 0;
502 for (i = 0; i < argc && i < MAX_TRACE_ARGS; i++) {
503 struct probe_arg *parg = &tu->tp.args[i];
504
505 /* Increment count for freeing args in error case */
506 tu->tp.nr_args++;
507
508 /* Parse argument name */
509 arg = strchr(argv[i], '=');
510 if (arg) {
511 *arg++ = '\0';
512 parg->name = kstrdup(argv[i], GFP_KERNEL);
513 } else {
514 arg = argv[i];
515 /* If argument name is omitted, set "argN" */
516 snprintf(buf, MAX_EVENT_NAME_LEN, "arg%d", i + 1);
517 parg->name = kstrdup(buf, GFP_KERNEL);
518 }
519
520 if (!parg->name) {
521 pr_info("Failed to allocate argument[%d] name.\n", i);
522 ret = -ENOMEM;
523 goto error;
524 }
525
526 if (!is_good_name(parg->name)) {
527 pr_info("Invalid argument[%d] name: %s\n", i, parg->name);
528 ret = -EINVAL;
529 goto error;
530 }
531
532 if (traceprobe_conflict_field_name(parg->name, tu->tp.args, i)) {
533 pr_info("Argument[%d] name '%s' conflicts with "
534 "another field.\n", i, argv[i]);
535 ret = -EINVAL;
536 goto error;
537 }
538
539 /* Parse fetch argument */
540 ret = traceprobe_parse_probe_arg(arg, &tu->tp.size, parg,
541 is_return, false,
542 uprobes_fetch_type_table);
543 if (ret) {
544 pr_info("Parse error at argument[%d]. (%d)\n", i, ret);
545 goto error;
546 }
547 }
548
549 ret = register_trace_uprobe(tu);
550 if (ret)
551 goto error;
552 return 0;
553
554 error:
555 free_trace_uprobe(tu);
556 return ret;
557
558 fail_address_parse:
559 iput(inode);
560
561 pr_info("Failed to parse address or file.\n");
562
563 return ret;
564 }
565
566 static int cleanup_all_probes(void)
567 {
568 struct trace_uprobe *tu;
569 int ret = 0;
570
571 mutex_lock(&uprobe_lock);
572 while (!list_empty(&uprobe_list)) {
573 tu = list_entry(uprobe_list.next, struct trace_uprobe, list);
574 ret = unregister_trace_uprobe(tu);
575 if (ret)
576 break;
577 }
578 mutex_unlock(&uprobe_lock);
579 return ret;
580 }
581
582 /* Probes listing interfaces */
583 static void *probes_seq_start(struct seq_file *m, loff_t *pos)
584 {
585 mutex_lock(&uprobe_lock);
586 return seq_list_start(&uprobe_list, *pos);
587 }
588
589 static void *probes_seq_next(struct seq_file *m, void *v, loff_t *pos)
590 {
591 return seq_list_next(v, &uprobe_list, pos);
592 }
593
594 static void probes_seq_stop(struct seq_file *m, void *v)
595 {
596 mutex_unlock(&uprobe_lock);
597 }
598
599 static int probes_seq_show(struct seq_file *m, void *v)
600 {
601 struct trace_uprobe *tu = v;
602 char c = is_ret_probe(tu) ? 'r' : 'p';
603 int i;
604
605 seq_printf(m, "%c:%s/%s", c, tu->tp.call.class->system,
606 trace_event_name(&tu->tp.call));
607 seq_printf(m, " %s:", tu->filename);
608
609 /* Don't print "0x (null)" when offset is 0 */
610 if (tu->offset) {
611 seq_printf(m, "0x%p", (void *)tu->offset);
612 } else {
613 switch (sizeof(void *)) {
614 case 4:
615 seq_printf(m, "0x00000000");
616 break;
617 case 8:
618 default:
619 seq_printf(m, "0x0000000000000000");
620 break;
621 }
622 }
623
624 for (i = 0; i < tu->tp.nr_args; i++)
625 seq_printf(m, " %s=%s", tu->tp.args[i].name, tu->tp.args[i].comm);
626
627 seq_putc(m, '\n');
628 return 0;
629 }
630
631 static const struct seq_operations probes_seq_op = {
632 .start = probes_seq_start,
633 .next = probes_seq_next,
634 .stop = probes_seq_stop,
635 .show = probes_seq_show
636 };
637
638 static int probes_open(struct inode *inode, struct file *file)
639 {
640 int ret;
641
642 if ((file->f_mode & FMODE_WRITE) && (file->f_flags & O_TRUNC)) {
643 ret = cleanup_all_probes();
644 if (ret)
645 return ret;
646 }
647
648 return seq_open(file, &probes_seq_op);
649 }
650
651 static ssize_t probes_write(struct file *file, const char __user *buffer,
652 size_t count, loff_t *ppos)
653 {
654 return trace_parse_run_command(file, buffer, count, ppos, create_trace_uprobe);
655 }
656
657 static const struct file_operations uprobe_events_ops = {
658 .owner = THIS_MODULE,
659 .open = probes_open,
660 .read = seq_read,
661 .llseek = seq_lseek,
662 .release = seq_release,
663 .write = probes_write,
664 };
665
666 /* Probes profiling interfaces */
667 static int probes_profile_seq_show(struct seq_file *m, void *v)
668 {
669 struct trace_uprobe *tu = v;
670
671 seq_printf(m, " %s %-44s %15lu\n", tu->filename,
672 trace_event_name(&tu->tp.call), tu->nhit);
673 return 0;
674 }
675
676 static const struct seq_operations profile_seq_op = {
677 .start = probes_seq_start,
678 .next = probes_seq_next,
679 .stop = probes_seq_stop,
680 .show = probes_profile_seq_show
681 };
682
683 static int profile_open(struct inode *inode, struct file *file)
684 {
685 return seq_open(file, &profile_seq_op);
686 }
687
688 static const struct file_operations uprobe_profile_ops = {
689 .owner = THIS_MODULE,
690 .open = profile_open,
691 .read = seq_read,
692 .llseek = seq_lseek,
693 .release = seq_release,
694 };
695
696 struct uprobe_cpu_buffer {
697 struct mutex mutex;
698 void *buf;
699 };
700 static struct uprobe_cpu_buffer __percpu *uprobe_cpu_buffer;
701 static int uprobe_buffer_refcnt;
702
703 static int uprobe_buffer_init(void)
704 {
705 int cpu, err_cpu;
706
707 uprobe_cpu_buffer = alloc_percpu(struct uprobe_cpu_buffer);
708 if (uprobe_cpu_buffer == NULL)
709 return -ENOMEM;
710
711 for_each_possible_cpu(cpu) {
712 struct page *p = alloc_pages_node(cpu_to_node(cpu),
713 GFP_KERNEL, 0);
714 if (p == NULL) {
715 err_cpu = cpu;
716 goto err;
717 }
718 per_cpu_ptr(uprobe_cpu_buffer, cpu)->buf = page_address(p);
719 mutex_init(&per_cpu_ptr(uprobe_cpu_buffer, cpu)->mutex);
720 }
721
722 return 0;
723
724 err:
725 for_each_possible_cpu(cpu) {
726 if (cpu == err_cpu)
727 break;
728 free_page((unsigned long)per_cpu_ptr(uprobe_cpu_buffer, cpu)->buf);
729 }
730
731 free_percpu(uprobe_cpu_buffer);
732 return -ENOMEM;
733 }
734
735 static int uprobe_buffer_enable(void)
736 {
737 int ret = 0;
738
739 BUG_ON(!mutex_is_locked(&event_mutex));
740
741 if (uprobe_buffer_refcnt++ == 0) {
742 ret = uprobe_buffer_init();
743 if (ret < 0)
744 uprobe_buffer_refcnt--;
745 }
746
747 return ret;
748 }
749
750 static void uprobe_buffer_disable(void)
751 {
752 int cpu;
753
754 BUG_ON(!mutex_is_locked(&event_mutex));
755
756 if (--uprobe_buffer_refcnt == 0) {
757 for_each_possible_cpu(cpu)
758 free_page((unsigned long)per_cpu_ptr(uprobe_cpu_buffer,
759 cpu)->buf);
760
761 free_percpu(uprobe_cpu_buffer);
762 uprobe_cpu_buffer = NULL;
763 }
764 }
765
766 static struct uprobe_cpu_buffer *uprobe_buffer_get(void)
767 {
768 struct uprobe_cpu_buffer *ucb;
769 int cpu;
770
771 cpu = raw_smp_processor_id();
772 ucb = per_cpu_ptr(uprobe_cpu_buffer, cpu);
773
774 /*
775 * Use per-cpu buffers for fastest access, but we might migrate
776 * so the mutex makes sure we have sole access to it.
777 */
778 mutex_lock(&ucb->mutex);
779
780 return ucb;
781 }
782
783 static void uprobe_buffer_put(struct uprobe_cpu_buffer *ucb)
784 {
785 mutex_unlock(&ucb->mutex);
786 }
787
788 static void __uprobe_trace_func(struct trace_uprobe *tu,
789 unsigned long func, struct pt_regs *regs,
790 struct uprobe_cpu_buffer *ucb, int dsize,
791 struct trace_event_file *trace_file)
792 {
793 struct uprobe_trace_entry_head *entry;
794 struct ring_buffer_event *event;
795 struct ring_buffer *buffer;
796 void *data;
797 int size, esize;
798 struct trace_event_call *call = &tu->tp.call;
799
800 WARN_ON(call != trace_file->event_call);
801
802 if (WARN_ON_ONCE(tu->tp.size + dsize > PAGE_SIZE))
803 return;
804
805 if (trace_trigger_soft_disabled(trace_file))
806 return;
807
808 esize = SIZEOF_TRACE_ENTRY(is_ret_probe(tu));
809 size = esize + tu->tp.size + dsize;
810 event = trace_event_buffer_lock_reserve(&buffer, trace_file,
811 call->event.type, size, 0, 0);
812 if (!event)
813 return;
814
815 entry = ring_buffer_event_data(event);
816 if (is_ret_probe(tu)) {
817 entry->vaddr[0] = func;
818 entry->vaddr[1] = instruction_pointer(regs);
819 data = DATAOF_TRACE_ENTRY(entry, true);
820 } else {
821 entry->vaddr[0] = instruction_pointer(regs);
822 data = DATAOF_TRACE_ENTRY(entry, false);
823 }
824
825 memcpy(data, ucb->buf, tu->tp.size + dsize);
826
827 event_trigger_unlock_commit(trace_file, buffer, event, entry, 0, 0);
828 }
829
830 /* uprobe handler */
831 static int uprobe_trace_func(struct trace_uprobe *tu, struct pt_regs *regs,
832 struct uprobe_cpu_buffer *ucb, int dsize)
833 {
834 struct event_file_link *link;
835
836 if (is_ret_probe(tu))
837 return 0;
838
839 rcu_read_lock();
840 list_for_each_entry_rcu(link, &tu->tp.files, list)
841 __uprobe_trace_func(tu, 0, regs, ucb, dsize, link->file);
842 rcu_read_unlock();
843
844 return 0;
845 }
846
847 static void uretprobe_trace_func(struct trace_uprobe *tu, unsigned long func,
848 struct pt_regs *regs,
849 struct uprobe_cpu_buffer *ucb, int dsize)
850 {
851 struct event_file_link *link;
852
853 rcu_read_lock();
854 list_for_each_entry_rcu(link, &tu->tp.files, list)
855 __uprobe_trace_func(tu, func, regs, ucb, dsize, link->file);
856 rcu_read_unlock();
857 }
858
859 /* Event entry printers */
860 static enum print_line_t
861 print_uprobe_event(struct trace_iterator *iter, int flags, struct trace_event *event)
862 {
863 struct uprobe_trace_entry_head *entry;
864 struct trace_seq *s = &iter->seq;
865 struct trace_uprobe *tu;
866 u8 *data;
867 int i;
868
869 entry = (struct uprobe_trace_entry_head *)iter->ent;
870 tu = container_of(event, struct trace_uprobe, tp.call.event);
871
872 if (is_ret_probe(tu)) {
873 trace_seq_printf(s, "%s: (0x%lx <- 0x%lx)",
874 trace_event_name(&tu->tp.call),
875 entry->vaddr[1], entry->vaddr[0]);
876 data = DATAOF_TRACE_ENTRY(entry, true);
877 } else {
878 trace_seq_printf(s, "%s: (0x%lx)",
879 trace_event_name(&tu->tp.call),
880 entry->vaddr[0]);
881 data = DATAOF_TRACE_ENTRY(entry, false);
882 }
883
884 for (i = 0; i < tu->tp.nr_args; i++) {
885 struct probe_arg *parg = &tu->tp.args[i];
886
887 if (!parg->type->print(s, parg->name, data + parg->offset, entry))
888 goto out;
889 }
890
891 trace_seq_putc(s, '\n');
892
893 out:
894 return trace_handle_return(s);
895 }
896
897 typedef bool (*filter_func_t)(struct uprobe_consumer *self,
898 enum uprobe_filter_ctx ctx,
899 struct mm_struct *mm);
900
901 static int
902 probe_event_enable(struct trace_uprobe *tu, struct trace_event_file *file,
903 filter_func_t filter)
904 {
905 bool enabled = trace_probe_is_enabled(&tu->tp);
906 struct event_file_link *link = NULL;
907 int ret;
908
909 if (file) {
910 if (tu->tp.flags & TP_FLAG_PROFILE)
911 return -EINTR;
912
913 link = kmalloc(sizeof(*link), GFP_KERNEL);
914 if (!link)
915 return -ENOMEM;
916
917 link->file = file;
918 list_add_tail_rcu(&link->list, &tu->tp.files);
919
920 tu->tp.flags |= TP_FLAG_TRACE;
921 } else {
922 if (tu->tp.flags & TP_FLAG_TRACE)
923 return -EINTR;
924
925 tu->tp.flags |= TP_FLAG_PROFILE;
926 }
927
928 WARN_ON(!uprobe_filter_is_empty(&tu->filter));
929
930 if (enabled)
931 return 0;
932
933 ret = uprobe_buffer_enable();
934 if (ret)
935 goto err_flags;
936
937 tu->consumer.filter = filter;
938 ret = uprobe_register(tu->inode, tu->offset, &tu->consumer);
939 if (ret)
940 goto err_buffer;
941
942 return 0;
943
944 err_buffer:
945 uprobe_buffer_disable();
946
947 err_flags:
948 if (file) {
949 list_del(&link->list);
950 kfree(link);
951 tu->tp.flags &= ~TP_FLAG_TRACE;
952 } else {
953 tu->tp.flags &= ~TP_FLAG_PROFILE;
954 }
955 return ret;
956 }
957
958 static void
959 probe_event_disable(struct trace_uprobe *tu, struct trace_event_file *file)
960 {
961 if (!trace_probe_is_enabled(&tu->tp))
962 return;
963
964 if (file) {
965 struct event_file_link *link;
966
967 link = find_event_file_link(&tu->tp, file);
968 if (!link)
969 return;
970
971 list_del_rcu(&link->list);
972 /* synchronize with u{,ret}probe_trace_func */
973 synchronize_sched();
974 kfree(link);
975
976 if (!list_empty(&tu->tp.files))
977 return;
978 }
979
980 WARN_ON(!uprobe_filter_is_empty(&tu->filter));
981
982 uprobe_unregister(tu->inode, tu->offset, &tu->consumer);
983 tu->tp.flags &= file ? ~TP_FLAG_TRACE : ~TP_FLAG_PROFILE;
984
985 uprobe_buffer_disable();
986 }
987
988 static int uprobe_event_define_fields(struct trace_event_call *event_call)
989 {
990 int ret, i, size;
991 struct uprobe_trace_entry_head field;
992 struct trace_uprobe *tu = event_call->data;
993
994 if (is_ret_probe(tu)) {
995 DEFINE_FIELD(unsigned long, vaddr[0], FIELD_STRING_FUNC, 0);
996 DEFINE_FIELD(unsigned long, vaddr[1], FIELD_STRING_RETIP, 0);
997 size = SIZEOF_TRACE_ENTRY(true);
998 } else {
999 DEFINE_FIELD(unsigned long, vaddr[0], FIELD_STRING_IP, 0);
1000 size = SIZEOF_TRACE_ENTRY(false);
1001 }
1002 /* Set argument names as fields */
1003 for (i = 0; i < tu->tp.nr_args; i++) {
1004 struct probe_arg *parg = &tu->tp.args[i];
1005
1006 ret = trace_define_field(event_call, parg->type->fmttype,
1007 parg->name, size + parg->offset,
1008 parg->type->size, parg->type->is_signed,
1009 FILTER_OTHER);
1010
1011 if (ret)
1012 return ret;
1013 }
1014 return 0;
1015 }
1016
1017 #ifdef CONFIG_PERF_EVENTS
1018 static bool
1019 __uprobe_perf_filter(struct trace_uprobe_filter *filter, struct mm_struct *mm)
1020 {
1021 struct perf_event *event;
1022
1023 if (filter->nr_systemwide)
1024 return true;
1025
1026 list_for_each_entry(event, &filter->perf_events, hw.tp_list) {
1027 if (event->hw.target->mm == mm)
1028 return true;
1029 }
1030
1031 return false;
1032 }
1033
1034 static inline bool
1035 uprobe_filter_event(struct trace_uprobe *tu, struct perf_event *event)
1036 {
1037 return __uprobe_perf_filter(&tu->filter, event->hw.target->mm);
1038 }
1039
1040 static int uprobe_perf_close(struct trace_uprobe *tu, struct perf_event *event)
1041 {
1042 bool done;
1043
1044 write_lock(&tu->filter.rwlock);
1045 if (event->hw.target) {
1046 list_del(&event->hw.tp_list);
1047 done = tu->filter.nr_systemwide ||
1048 (event->hw.target->flags & PF_EXITING) ||
1049 uprobe_filter_event(tu, event);
1050 } else {
1051 tu->filter.nr_systemwide--;
1052 done = tu->filter.nr_systemwide;
1053 }
1054 write_unlock(&tu->filter.rwlock);
1055
1056 if (!done)
1057 return uprobe_apply(tu->inode, tu->offset, &tu->consumer, false);
1058
1059 return 0;
1060 }
1061
1062 static int uprobe_perf_open(struct trace_uprobe *tu, struct perf_event *event)
1063 {
1064 bool done;
1065 int err;
1066
1067 write_lock(&tu->filter.rwlock);
1068 if (event->hw.target) {
1069 /*
1070 * event->parent != NULL means copy_process(), we can avoid
1071 * uprobe_apply(). current->mm must be probed and we can rely
1072 * on dup_mmap() which preserves the already installed bp's.
1073 *
1074 * attr.enable_on_exec means that exec/mmap will install the
1075 * breakpoints we need.
1076 */
1077 done = tu->filter.nr_systemwide ||
1078 event->parent || event->attr.enable_on_exec ||
1079 uprobe_filter_event(tu, event);
1080 list_add(&event->hw.tp_list, &tu->filter.perf_events);
1081 } else {
1082 done = tu->filter.nr_systemwide;
1083 tu->filter.nr_systemwide++;
1084 }
1085 write_unlock(&tu->filter.rwlock);
1086
1087 err = 0;
1088 if (!done) {
1089 err = uprobe_apply(tu->inode, tu->offset, &tu->consumer, true);
1090 if (err)
1091 uprobe_perf_close(tu, event);
1092 }
1093 return err;
1094 }
1095
1096 static bool uprobe_perf_filter(struct uprobe_consumer *uc,
1097 enum uprobe_filter_ctx ctx, struct mm_struct *mm)
1098 {
1099 struct trace_uprobe *tu;
1100 int ret;
1101
1102 tu = container_of(uc, struct trace_uprobe, consumer);
1103 read_lock(&tu->filter.rwlock);
1104 ret = __uprobe_perf_filter(&tu->filter, mm);
1105 read_unlock(&tu->filter.rwlock);
1106
1107 return ret;
1108 }
1109
1110 static void __uprobe_perf_func(struct trace_uprobe *tu,
1111 unsigned long func, struct pt_regs *regs,
1112 struct uprobe_cpu_buffer *ucb, int dsize)
1113 {
1114 struct trace_event_call *call = &tu->tp.call;
1115 struct uprobe_trace_entry_head *entry;
1116 struct hlist_head *head;
1117 void *data;
1118 int size, esize;
1119 int rctx;
1120
1121 if (bpf_prog_array_valid(call) && !trace_call_bpf(call, regs))
1122 return;
1123
1124 esize = SIZEOF_TRACE_ENTRY(is_ret_probe(tu));
1125
1126 size = esize + tu->tp.size + dsize;
1127 size = ALIGN(size + sizeof(u32), sizeof(u64)) - sizeof(u32);
1128 if (WARN_ONCE(size > PERF_MAX_TRACE_SIZE, "profile buffer not large enough"))
1129 return;
1130
1131 preempt_disable();
1132 head = this_cpu_ptr(call->perf_events);
1133 if (hlist_empty(head))
1134 goto out;
1135
1136 entry = perf_trace_buf_alloc(size, NULL, &rctx);
1137 if (!entry)
1138 goto out;
1139
1140 if (is_ret_probe(tu)) {
1141 entry->vaddr[0] = func;
1142 entry->vaddr[1] = instruction_pointer(regs);
1143 data = DATAOF_TRACE_ENTRY(entry, true);
1144 } else {
1145 entry->vaddr[0] = instruction_pointer(regs);
1146 data = DATAOF_TRACE_ENTRY(entry, false);
1147 }
1148
1149 memcpy(data, ucb->buf, tu->tp.size + dsize);
1150
1151 if (size - esize > tu->tp.size + dsize) {
1152 int len = tu->tp.size + dsize;
1153
1154 memset(data + len, 0, size - esize - len);
1155 }
1156
1157 perf_trace_buf_submit(entry, size, rctx, call->event.type, 1, regs,
1158 head, NULL);
1159 out:
1160 preempt_enable();
1161 }
1162
1163 /* uprobe profile handler */
1164 static int uprobe_perf_func(struct trace_uprobe *tu, struct pt_regs *regs,
1165 struct uprobe_cpu_buffer *ucb, int dsize)
1166 {
1167 if (!uprobe_perf_filter(&tu->consumer, 0, current->mm))
1168 return UPROBE_HANDLER_REMOVE;
1169
1170 if (!is_ret_probe(tu))
1171 __uprobe_perf_func(tu, 0, regs, ucb, dsize);
1172 return 0;
1173 }
1174
1175 static void uretprobe_perf_func(struct trace_uprobe *tu, unsigned long func,
1176 struct pt_regs *regs,
1177 struct uprobe_cpu_buffer *ucb, int dsize)
1178 {
1179 __uprobe_perf_func(tu, func, regs, ucb, dsize);
1180 }
1181 #endif /* CONFIG_PERF_EVENTS */
1182
1183 static int
1184 trace_uprobe_register(struct trace_event_call *event, enum trace_reg type,
1185 void *data)
1186 {
1187 struct trace_uprobe *tu = event->data;
1188 struct trace_event_file *file = data;
1189
1190 switch (type) {
1191 case TRACE_REG_REGISTER:
1192 return probe_event_enable(tu, file, NULL);
1193
1194 case TRACE_REG_UNREGISTER:
1195 probe_event_disable(tu, file);
1196 return 0;
1197
1198 #ifdef CONFIG_PERF_EVENTS
1199 case TRACE_REG_PERF_REGISTER:
1200 return probe_event_enable(tu, NULL, uprobe_perf_filter);
1201
1202 case TRACE_REG_PERF_UNREGISTER:
1203 probe_event_disable(tu, NULL);
1204 return 0;
1205
1206 case TRACE_REG_PERF_OPEN:
1207 return uprobe_perf_open(tu, data);
1208
1209 case TRACE_REG_PERF_CLOSE:
1210 return uprobe_perf_close(tu, data);
1211
1212 #endif
1213 default:
1214 return 0;
1215 }
1216 return 0;
1217 }
1218
1219 static int uprobe_dispatcher(struct uprobe_consumer *con, struct pt_regs *regs)
1220 {
1221 struct trace_uprobe *tu;
1222 struct uprobe_dispatch_data udd;
1223 struct uprobe_cpu_buffer *ucb;
1224 int dsize, esize;
1225 int ret = 0;
1226
1227
1228 tu = container_of(con, struct trace_uprobe, consumer);
1229 tu->nhit++;
1230
1231 udd.tu = tu;
1232 udd.bp_addr = instruction_pointer(regs);
1233
1234 current->utask->vaddr = (unsigned long) &udd;
1235
1236 if (WARN_ON_ONCE(!uprobe_cpu_buffer))
1237 return 0;
1238
1239 dsize = __get_data_size(&tu->tp, regs);
1240 esize = SIZEOF_TRACE_ENTRY(is_ret_probe(tu));
1241
1242 ucb = uprobe_buffer_get();
1243 store_trace_args(esize, &tu->tp, regs, ucb->buf, dsize);
1244
1245 if (tu->tp.flags & TP_FLAG_TRACE)
1246 ret |= uprobe_trace_func(tu, regs, ucb, dsize);
1247
1248 #ifdef CONFIG_PERF_EVENTS
1249 if (tu->tp.flags & TP_FLAG_PROFILE)
1250 ret |= uprobe_perf_func(tu, regs, ucb, dsize);
1251 #endif
1252 uprobe_buffer_put(ucb);
1253 return ret;
1254 }
1255
1256 static int uretprobe_dispatcher(struct uprobe_consumer *con,
1257 unsigned long func, struct pt_regs *regs)
1258 {
1259 struct trace_uprobe *tu;
1260 struct uprobe_dispatch_data udd;
1261 struct uprobe_cpu_buffer *ucb;
1262 int dsize, esize;
1263
1264 tu = container_of(con, struct trace_uprobe, consumer);
1265
1266 udd.tu = tu;
1267 udd.bp_addr = func;
1268
1269 current->utask->vaddr = (unsigned long) &udd;
1270
1271 if (WARN_ON_ONCE(!uprobe_cpu_buffer))
1272 return 0;
1273
1274 dsize = __get_data_size(&tu->tp, regs);
1275 esize = SIZEOF_TRACE_ENTRY(is_ret_probe(tu));
1276
1277 ucb = uprobe_buffer_get();
1278 store_trace_args(esize, &tu->tp, regs, ucb->buf, dsize);
1279
1280 if (tu->tp.flags & TP_FLAG_TRACE)
1281 uretprobe_trace_func(tu, func, regs, ucb, dsize);
1282
1283 #ifdef CONFIG_PERF_EVENTS
1284 if (tu->tp.flags & TP_FLAG_PROFILE)
1285 uretprobe_perf_func(tu, func, regs, ucb, dsize);
1286 #endif
1287 uprobe_buffer_put(ucb);
1288 return 0;
1289 }
1290
1291 static struct trace_event_functions uprobe_funcs = {
1292 .trace = print_uprobe_event
1293 };
1294
1295 static int register_uprobe_event(struct trace_uprobe *tu)
1296 {
1297 struct trace_event_call *call = &tu->tp.call;
1298 int ret;
1299
1300 /* Initialize trace_event_call */
1301 INIT_LIST_HEAD(&call->class->fields);
1302 call->event.funcs = &uprobe_funcs;
1303 call->class->define_fields = uprobe_event_define_fields;
1304
1305 if (set_print_fmt(&tu->tp, is_ret_probe(tu)) < 0)
1306 return -ENOMEM;
1307
1308 ret = register_trace_event(&call->event);
1309 if (!ret) {
1310 kfree(call->print_fmt);
1311 return -ENODEV;
1312 }
1313
1314 call->flags = TRACE_EVENT_FL_UPROBE;
1315 call->class->reg = trace_uprobe_register;
1316 call->data = tu;
1317 ret = trace_add_event_call(call);
1318
1319 if (ret) {
1320 pr_info("Failed to register uprobe event: %s\n",
1321 trace_event_name(call));
1322 kfree(call->print_fmt);
1323 unregister_trace_event(&call->event);
1324 }
1325
1326 return ret;
1327 }
1328
1329 static int unregister_uprobe_event(struct trace_uprobe *tu)
1330 {
1331 int ret;
1332
1333 /* tu->event is unregistered in trace_remove_event_call() */
1334 ret = trace_remove_event_call(&tu->tp.call);
1335 if (ret)
1336 return ret;
1337 kfree(tu->tp.call.print_fmt);
1338 tu->tp.call.print_fmt = NULL;
1339 return 0;
1340 }
1341
1342 /* Make a trace interface for controling probe points */
1343 static __init int init_uprobe_trace(void)
1344 {
1345 struct dentry *d_tracer;
1346
1347 d_tracer = tracing_init_dentry();
1348 if (IS_ERR(d_tracer))
1349 return 0;
1350
1351 trace_create_file("uprobe_events", 0644, d_tracer,
1352 NULL, &uprobe_events_ops);
1353 /* Profile interface */
1354 trace_create_file("uprobe_profile", 0444, d_tracer,
1355 NULL, &uprobe_profile_ops);
1356 return 0;
1357 }
1358
1359 fs_initcall(init_uprobe_trace);
Linux with added FPC-III support