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workqueue: async worker destruction
[linux-2.6/btrfs-unstable.git] / kernel / trace / trace_uprobe.c
blob930e51462dc871cf7bf038be265cc7ca281aad1c
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 __kprobes 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 __kprobes 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 __kprobes 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
153 if (ret < 0) { /* Failed to fetch string */
154 ((u8 *)get_rloc_data(dest))[0] = '\0';
155 *(u32 *)dest = make_data_rloc(0, get_rloc_offs(rloc));
156 } else {
157 *(u32 *)dest = make_data_rloc(ret, get_rloc_offs(rloc));
158 }
159 }
160
161 static __kprobes void FETCH_FUNC_NAME(memory, string_size)(struct pt_regs *regs,
162 void *addr, void *dest)
163 {
164 int len;
165 void __user *vaddr = (void __force __user *) addr;
166
167 len = strnlen_user(vaddr, MAX_STRING_SIZE);
168
169 if (len == 0 || len > MAX_STRING_SIZE) /* Failed to check length */
170 *(u32 *)dest = 0;
171 else
172 *(u32 *)dest = len;
173 }
174
175 static unsigned long translate_user_vaddr(void *file_offset)
176 {
177 unsigned long base_addr;
178 struct uprobe_dispatch_data *udd;
179
180 udd = (void *) current->utask->vaddr;
181
182 base_addr = udd->bp_addr - udd->tu->offset;
183 return base_addr + (unsigned long)file_offset;
184 }
185
186 #define DEFINE_FETCH_file_offset(type) \
187 static __kprobes void FETCH_FUNC_NAME(file_offset, type)(struct pt_regs *regs,\
188 void *offset, void *dest) \
189 { \
190 void *vaddr = (void *)translate_user_vaddr(offset); \
191 \
192 FETCH_FUNC_NAME(memory, type)(regs, vaddr, dest); \
193 }
194 DEFINE_BASIC_FETCH_FUNCS(file_offset)
195 DEFINE_FETCH_file_offset(string)
196 DEFINE_FETCH_file_offset(string_size)
197
198 /* Fetch type information table */
199 const struct fetch_type uprobes_fetch_type_table[] = {
200 /* Special types */
201 [FETCH_TYPE_STRING] = __ASSIGN_FETCH_TYPE("string", string, string,
202 sizeof(u32), 1, "__data_loc char[]"),
203 [FETCH_TYPE_STRSIZE] = __ASSIGN_FETCH_TYPE("string_size", u32,
204 string_size, sizeof(u32), 0, "u32"),
205 /* Basic types */
206 ASSIGN_FETCH_TYPE(u8, u8, 0),
207 ASSIGN_FETCH_TYPE(u16, u16, 0),
208 ASSIGN_FETCH_TYPE(u32, u32, 0),
209 ASSIGN_FETCH_TYPE(u64, u64, 0),
210 ASSIGN_FETCH_TYPE(s8, u8, 1),
211 ASSIGN_FETCH_TYPE(s16, u16, 1),
212 ASSIGN_FETCH_TYPE(s32, u32, 1),
213 ASSIGN_FETCH_TYPE(s64, u64, 1),
214
215 ASSIGN_FETCH_TYPE_END
216 };
217
218 static inline void init_trace_uprobe_filter(struct trace_uprobe_filter *filter)
219 {
220 rwlock_init(&filter->rwlock);
221 filter->nr_systemwide = 0;
222 INIT_LIST_HEAD(&filter->perf_events);
223 }
224
225 static inline bool uprobe_filter_is_empty(struct trace_uprobe_filter *filter)
226 {
227 return !filter->nr_systemwide && list_empty(&filter->perf_events);
228 }
229
230 static inline bool is_ret_probe(struct trace_uprobe *tu)
231 {
232 return tu->consumer.ret_handler != NULL;
233 }
234
235 /*
236 * Allocate new trace_uprobe and initialize it (including uprobes).
237 */
238 static struct trace_uprobe *
239 alloc_trace_uprobe(const char *group, const char *event, int nargs, bool is_ret)
240 {
241 struct trace_uprobe *tu;
242
243 if (!event || !is_good_name(event))
244 return ERR_PTR(-EINVAL);
245
246 if (!group || !is_good_name(group))
247 return ERR_PTR(-EINVAL);
248
249 tu = kzalloc(SIZEOF_TRACE_UPROBE(nargs), GFP_KERNEL);
250 if (!tu)
251 return ERR_PTR(-ENOMEM);
252
253 tu->tp.call.class = &tu->tp.class;
254 tu->tp.call.name = kstrdup(event, GFP_KERNEL);
255 if (!tu->tp.call.name)
256 goto error;
257
258 tu->tp.class.system = kstrdup(group, GFP_KERNEL);
259 if (!tu->tp.class.system)
260 goto error;
261
262 INIT_LIST_HEAD(&tu->list);
263 INIT_LIST_HEAD(&tu->tp.files);
264 tu->consumer.handler = uprobe_dispatcher;
265 if (is_ret)
266 tu->consumer.ret_handler = uretprobe_dispatcher;
267 init_trace_uprobe_filter(&tu->filter);
268 tu->tp.call.flags |= TRACE_EVENT_FL_USE_CALL_FILTER;
269 return tu;
270
271 error:
272 kfree(tu->tp.call.name);
273 kfree(tu);
274
275 return ERR_PTR(-ENOMEM);
276 }
277
278 static void free_trace_uprobe(struct trace_uprobe *tu)
279 {
280 int i;
281
282 for (i = 0; i < tu->tp.nr_args; i++)
283 traceprobe_free_probe_arg(&tu->tp.args[i]);
284
285 iput(tu->inode);
286 kfree(tu->tp.call.class->system);
287 kfree(tu->tp.call.name);
288 kfree(tu->filename);
289 kfree(tu);
290 }
291
292 static struct trace_uprobe *find_probe_event(const char *event, const char *group)
293 {
294 struct trace_uprobe *tu;
295
296 list_for_each_entry(tu, &uprobe_list, list)
297 if (strcmp(ftrace_event_name(&tu->tp.call), event) == 0 &&
298 strcmp(tu->tp.call.class->system, group) == 0)
299 return tu;
300
301 return NULL;
302 }
303
304 /* Unregister a trace_uprobe and probe_event: call with locking uprobe_lock */
305 static int unregister_trace_uprobe(struct trace_uprobe *tu)
306 {
307 int ret;
308
309 ret = unregister_uprobe_event(tu);
310 if (ret)
311 return ret;
312
313 list_del(&tu->list);
314 free_trace_uprobe(tu);
315 return 0;
316 }
317
318 /* Register a trace_uprobe and probe_event */
319 static int register_trace_uprobe(struct trace_uprobe *tu)
320 {
321 struct trace_uprobe *old_tu;
322 int ret;
323
324 mutex_lock(&uprobe_lock);
325
326 /* register as an event */
327 old_tu = find_probe_event(ftrace_event_name(&tu->tp.call),
328 tu->tp.call.class->system);
329 if (old_tu) {
330 /* delete old event */
331 ret = unregister_trace_uprobe(old_tu);
332 if (ret)
333 goto end;
334 }
335
336 ret = register_uprobe_event(tu);
337 if (ret) {
338 pr_warning("Failed to register probe event(%d)\n", ret);
339 goto end;
340 }
341
342 list_add_tail(&tu->list, &uprobe_list);
343
344 end:
345 mutex_unlock(&uprobe_lock);
346
347 return ret;
348 }
349
350 /*
351 * Argument syntax:
352 * - Add uprobe: p|r[:[GRP/]EVENT] PATH:OFFSET [FETCHARGS]
353 *
354 * - Remove uprobe: -:[GRP/]EVENT
355 */
356 static int create_trace_uprobe(int argc, char **argv)
357 {
358 struct trace_uprobe *tu;
359 struct inode *inode;
360 char *arg, *event, *group, *filename;
361 char buf[MAX_EVENT_NAME_LEN];
362 struct path path;
363 unsigned long offset;
364 bool is_delete, is_return;
365 int i, ret;
366
367 inode = NULL;
368 ret = 0;
369 is_delete = false;
370 is_return = false;
371 event = NULL;
372 group = NULL;
373
374 /* argc must be >= 1 */
375 if (argv[0][0] == '-')
376 is_delete = true;
377 else if (argv[0][0] == 'r')
378 is_return = true;
379 else if (argv[0][0] != 'p') {
380 pr_info("Probe definition must be started with 'p', 'r' or '-'.\n");
381 return -EINVAL;
382 }
383
384 if (argv[0][1] == ':') {
385 event = &argv[0][2];
386 arg = strchr(event, '/');
387
388 if (arg) {
389 group = event;
390 event = arg + 1;
391 event[-1] = '\0';
392
393 if (strlen(group) == 0) {
394 pr_info("Group name is not specified\n");
395 return -EINVAL;
396 }
397 }
398 if (strlen(event) == 0) {
399 pr_info("Event name is not specified\n");
400 return -EINVAL;
401 }
402 }
403 if (!group)
404 group = UPROBE_EVENT_SYSTEM;
405
406 if (is_delete) {
407 int ret;
408
409 if (!event) {
410 pr_info("Delete command needs an event name.\n");
411 return -EINVAL;
412 }
413 mutex_lock(&uprobe_lock);
414 tu = find_probe_event(event, group);
415
416 if (!tu) {
417 mutex_unlock(&uprobe_lock);
418 pr_info("Event %s/%s doesn't exist.\n", group, event);
419 return -ENOENT;
420 }
421 /* delete an event */
422 ret = unregister_trace_uprobe(tu);
423 mutex_unlock(&uprobe_lock);
424 return ret;
425 }
426
427 if (argc < 2) {
428 pr_info("Probe point is not specified.\n");
429 return -EINVAL;
430 }
431 if (isdigit(argv[1][0])) {
432 pr_info("probe point must be have a filename.\n");
433 return -EINVAL;
434 }
435 arg = strchr(argv[1], ':');
436 if (!arg) {
437 ret = -EINVAL;
438 goto fail_address_parse;
439 }
440
441 *arg++ = '\0';
442 filename = argv[1];
443 ret = kern_path(filename, LOOKUP_FOLLOW, &path);
444 if (ret)
445 goto fail_address_parse;
446
447 inode = igrab(path.dentry->d_inode);
448 path_put(&path);
449
450 if (!inode || !S_ISREG(inode->i_mode)) {
451 ret = -EINVAL;
452 goto fail_address_parse;
453 }
454
455 ret = kstrtoul(arg, 0, &offset);
456 if (ret)
457 goto fail_address_parse;
458
459 argc -= 2;
460 argv += 2;
461
462 /* setup a probe */
463 if (!event) {
464 char *tail;
465 char *ptr;
466
467 tail = kstrdup(kbasename(filename), GFP_KERNEL);
468 if (!tail) {
469 ret = -ENOMEM;
470 goto fail_address_parse;
471 }
472
473 ptr = strpbrk(tail, ".-_");
474 if (ptr)
475 *ptr = '\0';
476
477 snprintf(buf, MAX_EVENT_NAME_LEN, "%c_%s_0x%lx", 'p', tail, offset);
478 event = buf;
479 kfree(tail);
480 }
481
482 tu = alloc_trace_uprobe(group, event, argc, is_return);
483 if (IS_ERR(tu)) {
484 pr_info("Failed to allocate trace_uprobe.(%d)\n", (int)PTR_ERR(tu));
485 ret = PTR_ERR(tu);
486 goto fail_address_parse;
487 }
488 tu->offset = offset;
489 tu->inode = inode;
490 tu->filename = kstrdup(filename, GFP_KERNEL);
491
492 if (!tu->filename) {
493 pr_info("Failed to allocate filename.\n");
494 ret = -ENOMEM;
495 goto error;
496 }
497
498 /* parse arguments */
499 ret = 0;
500 for (i = 0; i < argc && i < MAX_TRACE_ARGS; i++) {
501 struct probe_arg *parg = &tu->tp.args[i];
502
503 /* Increment count for freeing args in error case */
504 tu->tp.nr_args++;
505
506 /* Parse argument name */
507 arg = strchr(argv[i], '=');
508 if (arg) {
509 *arg++ = '\0';
510 parg->name = kstrdup(argv[i], GFP_KERNEL);
511 } else {
512 arg = argv[i];
513 /* If argument name is omitted, set "argN" */
514 snprintf(buf, MAX_EVENT_NAME_LEN, "arg%d", i + 1);
515 parg->name = kstrdup(buf, GFP_KERNEL);
516 }
517
518 if (!parg->name) {
519 pr_info("Failed to allocate argument[%d] name.\n", i);
520 ret = -ENOMEM;
521 goto error;
522 }
523
524 if (!is_good_name(parg->name)) {
525 pr_info("Invalid argument[%d] name: %s\n", i, parg->name);
526 ret = -EINVAL;
527 goto error;
528 }
529
530 if (traceprobe_conflict_field_name(parg->name, tu->tp.args, i)) {
531 pr_info("Argument[%d] name '%s' conflicts with "
532 "another field.\n", i, argv[i]);
533 ret = -EINVAL;
534 goto error;
535 }
536
537 /* Parse fetch argument */
538 ret = traceprobe_parse_probe_arg(arg, &tu->tp.size, parg,
539 is_return, false);
540 if (ret) {
541 pr_info("Parse error at argument[%d]. (%d)\n", i, ret);
542 goto error;
543 }
544 }
545
546 ret = register_trace_uprobe(tu);
547 if (ret)
548 goto error;
549 return 0;
550
551 error:
552 free_trace_uprobe(tu);
553 return ret;
554
555 fail_address_parse:
556 if (inode)
557 iput(inode);
558
559 pr_info("Failed to parse address or file.\n");
560
561 return ret;
562 }
563
564 static int cleanup_all_probes(void)
565 {
566 struct trace_uprobe *tu;
567 int ret = 0;
568
569 mutex_lock(&uprobe_lock);
570 while (!list_empty(&uprobe_list)) {
571 tu = list_entry(uprobe_list.next, struct trace_uprobe, list);
572 ret = unregister_trace_uprobe(tu);
573 if (ret)
574 break;
575 }
576 mutex_unlock(&uprobe_lock);
577 return ret;
578 }
579
580 /* Probes listing interfaces */
581 static void *probes_seq_start(struct seq_file *m, loff_t *pos)
582 {
583 mutex_lock(&uprobe_lock);
584 return seq_list_start(&uprobe_list, *pos);
585 }
586
587 static void *probes_seq_next(struct seq_file *m, void *v, loff_t *pos)
588 {
589 return seq_list_next(v, &uprobe_list, pos);
590 }
591
592 static void probes_seq_stop(struct seq_file *m, void *v)
593 {
594 mutex_unlock(&uprobe_lock);
595 }
596
597 static int probes_seq_show(struct seq_file *m, void *v)
598 {
599 struct trace_uprobe *tu = v;
600 char c = is_ret_probe(tu) ? 'r' : 'p';
601 int i;
602
603 seq_printf(m, "%c:%s/%s", c, tu->tp.call.class->system,
604 ftrace_event_name(&tu->tp.call));
605 seq_printf(m, " %s:0x%p", tu->filename, (void *)tu->offset);
606
607 for (i = 0; i < tu->tp.nr_args; i++)
608 seq_printf(m, " %s=%s", tu->tp.args[i].name, tu->tp.args[i].comm);
609
610 seq_printf(m, "\n");
611 return 0;
612 }
613
614 static const struct seq_operations probes_seq_op = {
615 .start = probes_seq_start,
616 .next = probes_seq_next,
617 .stop = probes_seq_stop,
618 .show = probes_seq_show
619 };
620
621 static int probes_open(struct inode *inode, struct file *file)
622 {
623 int ret;
624
625 if ((file->f_mode & FMODE_WRITE) && (file->f_flags & O_TRUNC)) {
626 ret = cleanup_all_probes();
627 if (ret)
628 return ret;
629 }
630
631 return seq_open(file, &probes_seq_op);
632 }
633
634 static ssize_t probes_write(struct file *file, const char __user *buffer,
635 size_t count, loff_t *ppos)
636 {
637 return traceprobe_probes_write(file, buffer, count, ppos, create_trace_uprobe);
638 }
639
640 static const struct file_operations uprobe_events_ops = {
641 .owner = THIS_MODULE,
642 .open = probes_open,
643 .read = seq_read,
644 .llseek = seq_lseek,
645 .release = seq_release,
646 .write = probes_write,
647 };
648
649 /* Probes profiling interfaces */
650 static int probes_profile_seq_show(struct seq_file *m, void *v)
651 {
652 struct trace_uprobe *tu = v;
653
654 seq_printf(m, " %s %-44s %15lu\n", tu->filename,
655 ftrace_event_name(&tu->tp.call), tu->nhit);
656 return 0;
657 }
658
659 static const struct seq_operations profile_seq_op = {
660 .start = probes_seq_start,
661 .next = probes_seq_next,
662 .stop = probes_seq_stop,
663 .show = probes_profile_seq_show
664 };
665
666 static int profile_open(struct inode *inode, struct file *file)
667 {
668 return seq_open(file, &profile_seq_op);
669 }
670
671 static const struct file_operations uprobe_profile_ops = {
672 .owner = THIS_MODULE,
673 .open = profile_open,
674 .read = seq_read,
675 .llseek = seq_lseek,
676 .release = seq_release,
677 };
678
679 struct uprobe_cpu_buffer {
680 struct mutex mutex;
681 void *buf;
682 };
683 static struct uprobe_cpu_buffer __percpu *uprobe_cpu_buffer;
684 static int uprobe_buffer_refcnt;
685
686 static int uprobe_buffer_init(void)
687 {
688 int cpu, err_cpu;
689
690 uprobe_cpu_buffer = alloc_percpu(struct uprobe_cpu_buffer);
691 if (uprobe_cpu_buffer == NULL)
692 return -ENOMEM;
693
694 for_each_possible_cpu(cpu) {
695 struct page *p = alloc_pages_node(cpu_to_node(cpu),
696 GFP_KERNEL, 0);
697 if (p == NULL) {
698 err_cpu = cpu;
699 goto err;
700 }
701 per_cpu_ptr(uprobe_cpu_buffer, cpu)->buf = page_address(p);
702 mutex_init(&per_cpu_ptr(uprobe_cpu_buffer, cpu)->mutex);
703 }
704
705 return 0;
706
707 err:
708 for_each_possible_cpu(cpu) {
709 if (cpu == err_cpu)
710 break;
711 free_page((unsigned long)per_cpu_ptr(uprobe_cpu_buffer, cpu)->buf);
712 }
713
714 free_percpu(uprobe_cpu_buffer);
715 return -ENOMEM;
716 }
717
718 static int uprobe_buffer_enable(void)
719 {
720 int ret = 0;
721
722 BUG_ON(!mutex_is_locked(&event_mutex));
723
724 if (uprobe_buffer_refcnt++ == 0) {
725 ret = uprobe_buffer_init();
726 if (ret < 0)
727 uprobe_buffer_refcnt--;
728 }
729
730 return ret;
731 }
732
733 static void uprobe_buffer_disable(void)
734 {
735 BUG_ON(!mutex_is_locked(&event_mutex));
736
737 if (--uprobe_buffer_refcnt == 0) {
738 free_percpu(uprobe_cpu_buffer);
739 uprobe_cpu_buffer = NULL;
740 }
741 }
742
743 static struct uprobe_cpu_buffer *uprobe_buffer_get(void)
744 {
745 struct uprobe_cpu_buffer *ucb;
746 int cpu;
747
748 cpu = raw_smp_processor_id();
749 ucb = per_cpu_ptr(uprobe_cpu_buffer, cpu);
750
751 /*
752 * Use per-cpu buffers for fastest access, but we might migrate
753 * so the mutex makes sure we have sole access to it.
754 */
755 mutex_lock(&ucb->mutex);
756
757 return ucb;
758 }
759
760 static void uprobe_buffer_put(struct uprobe_cpu_buffer *ucb)
761 {
762 mutex_unlock(&ucb->mutex);
763 }
764
765 static void __uprobe_trace_func(struct trace_uprobe *tu,
766 unsigned long func, struct pt_regs *regs,
767 struct uprobe_cpu_buffer *ucb, int dsize,
768 struct ftrace_event_file *ftrace_file)
769 {
770 struct uprobe_trace_entry_head *entry;
771 struct ring_buffer_event *event;
772 struct ring_buffer *buffer;
773 void *data;
774 int size, esize;
775 struct ftrace_event_call *call = &tu->tp.call;
776
777 WARN_ON(call != ftrace_file->event_call);
778
779 if (WARN_ON_ONCE(tu->tp.size + dsize > PAGE_SIZE))
780 return;
781
782 if (ftrace_trigger_soft_disabled(ftrace_file))
783 return;
784
785 esize = SIZEOF_TRACE_ENTRY(is_ret_probe(tu));
786 size = esize + tu->tp.size + dsize;
787 event = trace_event_buffer_lock_reserve(&buffer, ftrace_file,
788 call->event.type, size, 0, 0);
789 if (!event)
790 return;
791
792 entry = ring_buffer_event_data(event);
793 if (is_ret_probe(tu)) {
794 entry->vaddr[0] = func;
795 entry->vaddr[1] = instruction_pointer(regs);
796 data = DATAOF_TRACE_ENTRY(entry, true);
797 } else {
798 entry->vaddr[0] = instruction_pointer(regs);
799 data = DATAOF_TRACE_ENTRY(entry, false);
800 }
801
802 memcpy(data, ucb->buf, tu->tp.size + dsize);
803
804 event_trigger_unlock_commit(ftrace_file, buffer, event, entry, 0, 0);
805 }
806
807 /* uprobe handler */
808 static int uprobe_trace_func(struct trace_uprobe *tu, struct pt_regs *regs,
809 struct uprobe_cpu_buffer *ucb, int dsize)
810 {
811 struct event_file_link *link;
812
813 if (is_ret_probe(tu))
814 return 0;
815
816 rcu_read_lock();
817 list_for_each_entry_rcu(link, &tu->tp.files, list)
818 __uprobe_trace_func(tu, 0, regs, ucb, dsize, link->file);
819 rcu_read_unlock();
820
821 return 0;
822 }
823
824 static void uretprobe_trace_func(struct trace_uprobe *tu, unsigned long func,
825 struct pt_regs *regs,
826 struct uprobe_cpu_buffer *ucb, int dsize)
827 {
828 struct event_file_link *link;
829
830 rcu_read_lock();
831 list_for_each_entry_rcu(link, &tu->tp.files, list)
832 __uprobe_trace_func(tu, func, regs, ucb, dsize, link->file);
833 rcu_read_unlock();
834 }
835
836 /* Event entry printers */
837 static enum print_line_t
838 print_uprobe_event(struct trace_iterator *iter, int flags, struct trace_event *event)
839 {
840 struct uprobe_trace_entry_head *entry;
841 struct trace_seq *s = &iter->seq;
842 struct trace_uprobe *tu;
843 u8 *data;
844 int i;
845
846 entry = (struct uprobe_trace_entry_head *)iter->ent;
847 tu = container_of(event, struct trace_uprobe, tp.call.event);
848
849 if (is_ret_probe(tu)) {
850 if (!trace_seq_printf(s, "%s: (0x%lx <- 0x%lx)",
851 ftrace_event_name(&tu->tp.call),
852 entry->vaddr[1], entry->vaddr[0]))
853 goto partial;
854 data = DATAOF_TRACE_ENTRY(entry, true);
855 } else {
856 if (!trace_seq_printf(s, "%s: (0x%lx)",
857 ftrace_event_name(&tu->tp.call),
858 entry->vaddr[0]))
859 goto partial;
860 data = DATAOF_TRACE_ENTRY(entry, false);
861 }
862
863 for (i = 0; i < tu->tp.nr_args; i++) {
864 struct probe_arg *parg = &tu->tp.args[i];
865
866 if (!parg->type->print(s, parg->name, data + parg->offset, entry))
867 goto partial;
868 }
869
870 if (trace_seq_puts(s, "\n"))
871 return TRACE_TYPE_HANDLED;
872
873 partial:
874 return TRACE_TYPE_PARTIAL_LINE;
875 }
876
877 typedef bool (*filter_func_t)(struct uprobe_consumer *self,
878 enum uprobe_filter_ctx ctx,
879 struct mm_struct *mm);
880
881 static int
882 probe_event_enable(struct trace_uprobe *tu, struct ftrace_event_file *file,
883 filter_func_t filter)
884 {
885 bool enabled = trace_probe_is_enabled(&tu->tp);
886 struct event_file_link *link = NULL;
887 int ret;
888
889 if (file) {
890 link = kmalloc(sizeof(*link), GFP_KERNEL);
891 if (!link)
892 return -ENOMEM;
893
894 link->file = file;
895 list_add_tail_rcu(&link->list, &tu->tp.files);
896
897 tu->tp.flags |= TP_FLAG_TRACE;
898 } else
899 tu->tp.flags |= TP_FLAG_PROFILE;
900
901 ret = uprobe_buffer_enable();
902 if (ret < 0)
903 return ret;
904
905 WARN_ON(!uprobe_filter_is_empty(&tu->filter));
906
907 if (enabled)
908 return 0;
909
910 tu->consumer.filter = filter;
911 ret = uprobe_register(tu->inode, tu->offset, &tu->consumer);
912 if (ret) {
913 if (file) {
914 list_del(&link->list);
915 kfree(link);
916 tu->tp.flags &= ~TP_FLAG_TRACE;
917 } else
918 tu->tp.flags &= ~TP_FLAG_PROFILE;
919 }
920
921 return ret;
922 }
923
924 static void
925 probe_event_disable(struct trace_uprobe *tu, struct ftrace_event_file *file)
926 {
927 if (!trace_probe_is_enabled(&tu->tp))
928 return;
929
930 if (file) {
931 struct event_file_link *link;
932
933 link = find_event_file_link(&tu->tp, file);
934 if (!link)
935 return;
936
937 list_del_rcu(&link->list);
938 /* synchronize with u{,ret}probe_trace_func */
939 synchronize_sched();
940 kfree(link);
941
942 if (!list_empty(&tu->tp.files))
943 return;
944 }
945
946 WARN_ON(!uprobe_filter_is_empty(&tu->filter));
947
948 uprobe_unregister(tu->inode, tu->offset, &tu->consumer);
949 tu->tp.flags &= file ? ~TP_FLAG_TRACE : ~TP_FLAG_PROFILE;
950
951 uprobe_buffer_disable();
952 }
953
954 static int uprobe_event_define_fields(struct ftrace_event_call *event_call)
955 {
956 int ret, i, size;
957 struct uprobe_trace_entry_head field;
958 struct trace_uprobe *tu = event_call->data;
959
960 if (is_ret_probe(tu)) {
961 DEFINE_FIELD(unsigned long, vaddr[0], FIELD_STRING_FUNC, 0);
962 DEFINE_FIELD(unsigned long, vaddr[1], FIELD_STRING_RETIP, 0);
963 size = SIZEOF_TRACE_ENTRY(true);
964 } else {
965 DEFINE_FIELD(unsigned long, vaddr[0], FIELD_STRING_IP, 0);
966 size = SIZEOF_TRACE_ENTRY(false);
967 }
968 /* Set argument names as fields */
969 for (i = 0; i < tu->tp.nr_args; i++) {
970 struct probe_arg *parg = &tu->tp.args[i];
971
972 ret = trace_define_field(event_call, parg->type->fmttype,
973 parg->name, size + parg->offset,
974 parg->type->size, parg->type->is_signed,
975 FILTER_OTHER);
976
977 if (ret)
978 return ret;
979 }
980 return 0;
981 }
982
983 #ifdef CONFIG_PERF_EVENTS
984 static bool
985 __uprobe_perf_filter(struct trace_uprobe_filter *filter, struct mm_struct *mm)
986 {
987 struct perf_event *event;
988
989 if (filter->nr_systemwide)
990 return true;
991
992 list_for_each_entry(event, &filter->perf_events, hw.tp_list) {
993 if (event->hw.tp_target->mm == mm)
994 return true;
995 }
996
997 return false;
998 }
999
1000 static inline bool
1001 uprobe_filter_event(struct trace_uprobe *tu, struct perf_event *event)
1002 {
1003 return __uprobe_perf_filter(&tu->filter, event->hw.tp_target->mm);
1004 }
1005
1006 static int uprobe_perf_open(struct trace_uprobe *tu, struct perf_event *event)
1007 {
1008 bool done;
1009
1010 write_lock(&tu->filter.rwlock);
1011 if (event->hw.tp_target) {
1012 /*
1013 * event->parent != NULL means copy_process(), we can avoid
1014 * uprobe_apply(). current->mm must be probed and we can rely
1015 * on dup_mmap() which preserves the already installed bp's.
1016 *
1017 * attr.enable_on_exec means that exec/mmap will install the
1018 * breakpoints we need.
1019 */
1020 done = tu->filter.nr_systemwide ||
1021 event->parent || event->attr.enable_on_exec ||
1022 uprobe_filter_event(tu, event);
1023 list_add(&event->hw.tp_list, &tu->filter.perf_events);
1024 } else {
1025 done = tu->filter.nr_systemwide;
1026 tu->filter.nr_systemwide++;
1027 }
1028 write_unlock(&tu->filter.rwlock);
1029
1030 if (!done)
1031 uprobe_apply(tu->inode, tu->offset, &tu->consumer, true);
1032
1033 return 0;
1034 }
1035
1036 static int uprobe_perf_close(struct trace_uprobe *tu, struct perf_event *event)
1037 {
1038 bool done;
1039
1040 write_lock(&tu->filter.rwlock);
1041 if (event->hw.tp_target) {
1042 list_del(&event->hw.tp_list);
1043 done = tu->filter.nr_systemwide ||
1044 (event->hw.tp_target->flags & PF_EXITING) ||
1045 uprobe_filter_event(tu, event);
1046 } else {
1047 tu->filter.nr_systemwide--;
1048 done = tu->filter.nr_systemwide;
1049 }
1050 write_unlock(&tu->filter.rwlock);
1051
1052 if (!done)
1053 uprobe_apply(tu->inode, tu->offset, &tu->consumer, false);
1054
1055 return 0;
1056 }
1057
1058 static bool uprobe_perf_filter(struct uprobe_consumer *uc,
1059 enum uprobe_filter_ctx ctx, struct mm_struct *mm)
1060 {
1061 struct trace_uprobe *tu;
1062 int ret;
1063
1064 tu = container_of(uc, struct trace_uprobe, consumer);
1065 read_lock(&tu->filter.rwlock);
1066 ret = __uprobe_perf_filter(&tu->filter, mm);
1067 read_unlock(&tu->filter.rwlock);
1068
1069 return ret;
1070 }
1071
1072 static void __uprobe_perf_func(struct trace_uprobe *tu,
1073 unsigned long func, struct pt_regs *regs,
1074 struct uprobe_cpu_buffer *ucb, int dsize)
1075 {
1076 struct ftrace_event_call *call = &tu->tp.call;
1077 struct uprobe_trace_entry_head *entry;
1078 struct hlist_head *head;
1079 void *data;
1080 int size, esize;
1081 int rctx;
1082
1083 esize = SIZEOF_TRACE_ENTRY(is_ret_probe(tu));
1084
1085 size = esize + tu->tp.size + dsize;
1086 size = ALIGN(size + sizeof(u32), sizeof(u64)) - sizeof(u32);
1087 if (WARN_ONCE(size > PERF_MAX_TRACE_SIZE, "profile buffer not large enough"))
1088 return;
1089
1090 preempt_disable();
1091 head = this_cpu_ptr(call->perf_events);
1092 if (hlist_empty(head))
1093 goto out;
1094
1095 entry = perf_trace_buf_prepare(size, call->event.type, regs, &rctx);
1096 if (!entry)
1097 goto out;
1098
1099 if (is_ret_probe(tu)) {
1100 entry->vaddr[0] = func;
1101 entry->vaddr[1] = instruction_pointer(regs);
1102 data = DATAOF_TRACE_ENTRY(entry, true);
1103 } else {
1104 entry->vaddr[0] = instruction_pointer(regs);
1105 data = DATAOF_TRACE_ENTRY(entry, false);
1106 }
1107
1108 memcpy(data, ucb->buf, tu->tp.size + dsize);
1109
1110 if (size - esize > tu->tp.size + dsize) {
1111 int len = tu->tp.size + dsize;
1112
1113 memset(data + len, 0, size - esize - len);
1114 }
1115
1116 perf_trace_buf_submit(entry, size, rctx, 0, 1, regs, head, NULL);
1117 out:
1118 preempt_enable();
1119 }
1120
1121 /* uprobe profile handler */
1122 static int uprobe_perf_func(struct trace_uprobe *tu, struct pt_regs *regs,
1123 struct uprobe_cpu_buffer *ucb, int dsize)
1124 {
1125 if (!uprobe_perf_filter(&tu->consumer, 0, current->mm))
1126 return UPROBE_HANDLER_REMOVE;
1127
1128 if (!is_ret_probe(tu))
1129 __uprobe_perf_func(tu, 0, regs, ucb, dsize);
1130 return 0;
1131 }
1132
1133 static void uretprobe_perf_func(struct trace_uprobe *tu, unsigned long func,
1134 struct pt_regs *regs,
1135 struct uprobe_cpu_buffer *ucb, int dsize)
1136 {
1137 __uprobe_perf_func(tu, func, regs, ucb, dsize);
1138 }
1139 #endif /* CONFIG_PERF_EVENTS */
1140
1141 static int
1142 trace_uprobe_register(struct ftrace_event_call *event, enum trace_reg type,
1143 void *data)
1144 {
1145 struct trace_uprobe *tu = event->data;
1146 struct ftrace_event_file *file = data;
1147
1148 switch (type) {
1149 case TRACE_REG_REGISTER:
1150 return probe_event_enable(tu, file, NULL);
1151
1152 case TRACE_REG_UNREGISTER:
1153 probe_event_disable(tu, file);
1154 return 0;
1155
1156 #ifdef CONFIG_PERF_EVENTS
1157 case TRACE_REG_PERF_REGISTER:
1158 return probe_event_enable(tu, NULL, uprobe_perf_filter);
1159
1160 case TRACE_REG_PERF_UNREGISTER:
1161 probe_event_disable(tu, NULL);
1162 return 0;
1163
1164 case TRACE_REG_PERF_OPEN:
1165 return uprobe_perf_open(tu, data);
1166
1167 case TRACE_REG_PERF_CLOSE:
1168 return uprobe_perf_close(tu, data);
1169
1170 #endif
1171 default:
1172 return 0;
1173 }
1174 return 0;
1175 }
1176
1177 static int uprobe_dispatcher(struct uprobe_consumer *con, struct pt_regs *regs)
1178 {
1179 struct trace_uprobe *tu;
1180 struct uprobe_dispatch_data udd;
1181 struct uprobe_cpu_buffer *ucb;
1182 int dsize, esize;
1183 int ret = 0;
1184
1185
1186 tu = container_of(con, struct trace_uprobe, consumer);
1187 tu->nhit++;
1188
1189 udd.tu = tu;
1190 udd.bp_addr = instruction_pointer(regs);
1191
1192 current->utask->vaddr = (unsigned long) &udd;
1193
1194 #ifdef CONFIG_PERF_EVENTS
1195 if ((tu->tp.flags & TP_FLAG_TRACE) == 0 &&
1196 !uprobe_perf_filter(&tu->consumer, 0, current->mm))
1197 return UPROBE_HANDLER_REMOVE;
1198 #endif
1199
1200 if (WARN_ON_ONCE(!uprobe_cpu_buffer))
1201 return 0;
1202
1203 dsize = __get_data_size(&tu->tp, regs);
1204 esize = SIZEOF_TRACE_ENTRY(is_ret_probe(tu));
1205
1206 ucb = uprobe_buffer_get();
1207 store_trace_args(esize, &tu->tp, regs, ucb->buf, dsize);
1208
1209 if (tu->tp.flags & TP_FLAG_TRACE)
1210 ret |= uprobe_trace_func(tu, regs, ucb, dsize);
1211
1212 #ifdef CONFIG_PERF_EVENTS
1213 if (tu->tp.flags & TP_FLAG_PROFILE)
1214 ret |= uprobe_perf_func(tu, regs, ucb, dsize);
1215 #endif
1216 uprobe_buffer_put(ucb);
1217 return ret;
1218 }
1219
1220 static int uretprobe_dispatcher(struct uprobe_consumer *con,
1221 unsigned long func, struct pt_regs *regs)
1222 {
1223 struct trace_uprobe *tu;
1224 struct uprobe_dispatch_data udd;
1225 struct uprobe_cpu_buffer *ucb;
1226 int dsize, esize;
1227
1228 tu = container_of(con, struct trace_uprobe, consumer);
1229
1230 udd.tu = tu;
1231 udd.bp_addr = func;
1232
1233 current->utask->vaddr = (unsigned long) &udd;
1234
1235 if (WARN_ON_ONCE(!uprobe_cpu_buffer))
1236 return 0;
1237
1238 dsize = __get_data_size(&tu->tp, regs);
1239 esize = SIZEOF_TRACE_ENTRY(is_ret_probe(tu));
1240
1241 ucb = uprobe_buffer_get();
1242 store_trace_args(esize, &tu->tp, regs, ucb->buf, dsize);
1243
1244 if (tu->tp.flags & TP_FLAG_TRACE)
1245 uretprobe_trace_func(tu, func, regs, ucb, dsize);
1246
1247 #ifdef CONFIG_PERF_EVENTS
1248 if (tu->tp.flags & TP_FLAG_PROFILE)
1249 uretprobe_perf_func(tu, func, regs, ucb, dsize);
1250 #endif
1251 uprobe_buffer_put(ucb);
1252 return 0;
1253 }
1254
1255 static struct trace_event_functions uprobe_funcs = {
1256 .trace = print_uprobe_event
1257 };
1258
1259 static int register_uprobe_event(struct trace_uprobe *tu)
1260 {
1261 struct ftrace_event_call *call = &tu->tp.call;
1262 int ret;
1263
1264 /* Initialize ftrace_event_call */
1265 INIT_LIST_HEAD(&call->class->fields);
1266 call->event.funcs = &uprobe_funcs;
1267 call->class->define_fields = uprobe_event_define_fields;
1268
1269 if (set_print_fmt(&tu->tp, is_ret_probe(tu)) < 0)
1270 return -ENOMEM;
1271
1272 ret = register_ftrace_event(&call->event);
1273 if (!ret) {
1274 kfree(call->print_fmt);
1275 return -ENODEV;
1276 }
1277 call->flags = 0;
1278 call->class->reg = trace_uprobe_register;
1279 call->data = tu;
1280 ret = trace_add_event_call(call);
1281
1282 if (ret) {
1283 pr_info("Failed to register uprobe event: %s\n",
1284 ftrace_event_name(call));
1285 kfree(call->print_fmt);
1286 unregister_ftrace_event(&call->event);
1287 }
1288
1289 return ret;
1290 }
1291
1292 static int unregister_uprobe_event(struct trace_uprobe *tu)
1293 {
1294 int ret;
1295
1296 /* tu->event is unregistered in trace_remove_event_call() */
1297 ret = trace_remove_event_call(&tu->tp.call);
1298 if (ret)
1299 return ret;
1300 kfree(tu->tp.call.print_fmt);
1301 tu->tp.call.print_fmt = NULL;
1302 return 0;
1303 }
1304
1305 /* Make a trace interface for controling probe points */
1306 static __init int init_uprobe_trace(void)
1307 {
1308 struct dentry *d_tracer;
1309
1310 d_tracer = tracing_init_dentry();
1311 if (!d_tracer)
1312 return 0;
1313
1314 trace_create_file("uprobe_events", 0644, d_tracer,
1315 NULL, &uprobe_events_ops);
1316 /* Profile interface */
1317 trace_create_file("uprobe_profile", 0444, d_tracer,
1318 NULL, &uprobe_profile_ops);
1319 return 0;
1320 }
1321
1322 fs_initcall(init_uprobe_trace);
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