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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
31struct 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
43struct 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 */
52struct 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
67static int register_uprobe_event(struct trace_uprobe *tu);
68static int unregister_uprobe_event(struct trace_uprobe *tu);
69
70static DEFINE_MUTEX(uprobe_lock);
71static LIST_HEAD(uprobe_list);
72
73struct uprobe_dispatch_data {
74 struct trace_uprobe *tu;
75 unsigned long bp_addr;
76};
77
78static int uprobe_dispatcher(struct uprobe_consumer *con, struct pt_regs *regs);
79static int uretprobe_dispatcher(struct uprobe_consumer *con,
80 unsigned long func, struct pt_regs *regs);
81
82#ifdef CONFIG_STACK_GROWSUP
83static unsigned long adjust_stack_addr(unsigned long addr, unsigned int n)
84{
85 return addr - (n * sizeof(long));
86}
87#else
88static unsigned long adjust_stack_addr(unsigned long addr, unsigned int n)
89{
90 return addr + (n * sizeof(long));
91}
92#endif
93
94static 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) \
111static 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}
117DEFINE_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) \
123static 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}
134DEFINE_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 */
139static 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
161static 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
175static 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) \
187static 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}
194DEFINE_BASIC_FETCH_FUNCS(file_offset)
195DEFINE_FETCH_file_offset(string)
196DEFINE_FETCH_file_offset(string_size)
197
198/* Fetch type information table */
199static 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
218static 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
225static inline bool uprobe_filter_is_empty(struct trace_uprobe_filter *filter)
226{
227 return !filter->nr_systemwide && list_empty(&filter->perf_events);
228}
229
230static 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 */
238static struct trace_uprobe *
239alloc_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 return tu;
269
270error:
271 kfree(tu->tp.call.name);
272 kfree(tu);
273
274 return ERR_PTR(-ENOMEM);
275}
276
277static void free_trace_uprobe(struct trace_uprobe *tu)
278{
279 int i;
280
281 for (i = 0; i < tu->tp.nr_args; i++)
282 traceprobe_free_probe_arg(&tu->tp.args[i]);
283
284 iput(tu->inode);
285 kfree(tu->tp.call.class->system);
286 kfree(tu->tp.call.name);
287 kfree(tu->filename);
288 kfree(tu);
289}
290
291static struct trace_uprobe *find_probe_event(const char *event, const char *group)
292{
293 struct trace_uprobe *tu;
294
295 list_for_each_entry(tu, &uprobe_list, list)
296 if (strcmp(trace_event_name(&tu->tp.call), event) == 0 &&
297 strcmp(tu->tp.call.class->system, group) == 0)
298 return tu;
299
300 return NULL;
301}
302
303/* Unregister a trace_uprobe and probe_event: call with locking uprobe_lock */
304static int unregister_trace_uprobe(struct trace_uprobe *tu)
305{
306 int ret;
307
308 ret = unregister_uprobe_event(tu);
309 if (ret)
310 return ret;
311
312 list_del(&tu->list);
313 free_trace_uprobe(tu);
314 return 0;
315}
316
317/* Register a trace_uprobe and probe_event */
318static int register_trace_uprobe(struct trace_uprobe *tu)
319{
320 struct trace_uprobe *old_tu;
321 int ret;
322
323 mutex_lock(&uprobe_lock);
324
325 /* register as an event */
326 old_tu = find_probe_event(trace_event_name(&tu->tp.call),
327 tu->tp.call.class->system);
328 if (old_tu) {
329 /* delete old event */
330 ret = unregister_trace_uprobe(old_tu);
331 if (ret)
332 goto end;
333 }
334
335 ret = register_uprobe_event(tu);
336 if (ret) {
337 pr_warn("Failed to register probe event(%d)\n", ret);
338 goto end;
339 }
340
341 list_add_tail(&tu->list, &uprobe_list);
342
343end:
344 mutex_unlock(&uprobe_lock);
345
346 return ret;
347}
348
349/*
350 * Argument syntax:
351 * - Add uprobe: p|r[:[GRP/]EVENT] PATH:OFFSET [FETCHARGS]
352 *
353 * - Remove uprobe: -:[GRP/]EVENT
354 */
355static int create_trace_uprobe(int argc, char **argv)
356{
357 struct trace_uprobe *tu;
358 struct inode *inode;
359 char *arg, *event, *group, *filename;
360 char buf[MAX_EVENT_NAME_LEN];
361 struct path path;
362 unsigned long offset;
363 bool is_delete, is_return;
364 int i, ret;
365
366 inode = NULL;
367 ret = 0;
368 is_delete = false;
369 is_return = false;
370 event = NULL;
371 group = NULL;
372
373 /* argc must be >= 1 */
374 if (argv[0][0] == '-')
375 is_delete = true;
376 else if (argv[0][0] == 'r')
377 is_return = true;
378 else if (argv[0][0] != 'p') {
379 pr_info("Probe definition must be started with 'p', 'r' or '-'.\n");
380 return -EINVAL;
381 }
382
383 if (argv[0][1] == ':') {
384 event = &argv[0][2];
385 arg = strchr(event, '/');
386
387 if (arg) {
388 group = event;
389 event = arg + 1;
390 event[-1] = '\0';
391
392 if (strlen(group) == 0) {
393 pr_info("Group name is not specified\n");
394 return -EINVAL;
395 }
396 }
397 if (strlen(event) == 0) {
398 pr_info("Event name is not specified\n");
399 return -EINVAL;
400 }
401 }
402 if (!group)
403 group = UPROBE_EVENT_SYSTEM;
404
405 if (is_delete) {
406 int ret;
407
408 if (!event) {
409 pr_info("Delete command needs an event name.\n");
410 return -EINVAL;
411 }
412 mutex_lock(&uprobe_lock);
413 tu = find_probe_event(event, group);
414
415 if (!tu) {
416 mutex_unlock(&uprobe_lock);
417 pr_info("Event %s/%s doesn't exist.\n", group, event);
418 return -ENOENT;
419 }
420 /* delete an event */
421 ret = unregister_trace_uprobe(tu);
422 mutex_unlock(&uprobe_lock);
423 return ret;
424 }
425
426 if (argc < 2) {
427 pr_info("Probe point is not specified.\n");
428 return -EINVAL;
429 }
430 if (isdigit(argv[1][0])) {
431 pr_info("probe point must be have a filename.\n");
432 return -EINVAL;
433 }
434 arg = strchr(argv[1], ':');
435 if (!arg) {
436 ret = -EINVAL;
437 goto fail_address_parse;
438 }
439
440 *arg++ = '\0';
441 filename = argv[1];
442 ret = kern_path(filename, LOOKUP_FOLLOW, &path);
443 if (ret)
444 goto fail_address_parse;
445
446 inode = igrab(d_inode(path.dentry));
447 path_put(&path);
448
449 if (!inode || !S_ISREG(inode->i_mode)) {
450 ret = -EINVAL;
451 goto fail_address_parse;
452 }
453
454 ret = kstrtoul(arg, 0, &offset);
455 if (ret)
456 goto fail_address_parse;
457
458 argc -= 2;
459 argv += 2;
460
461 /* setup a probe */
462 if (!event) {
463 char *tail;
464 char *ptr;
465
466 tail = kstrdup(kbasename(filename), GFP_KERNEL);
467 if (!tail) {
468 ret = -ENOMEM;
469 goto fail_address_parse;
470 }
471
472 ptr = strpbrk(tail, ".-_");
473 if (ptr)
474 *ptr = '\0';
475
476 snprintf(buf, MAX_EVENT_NAME_LEN, "%c_%s_0x%lx", 'p', tail, offset);
477 event = buf;
478 kfree(tail);
479 }
480
481 tu = alloc_trace_uprobe(group, event, argc, is_return);
482 if (IS_ERR(tu)) {
483 pr_info("Failed to allocate trace_uprobe.(%d)\n", (int)PTR_ERR(tu));
484 ret = PTR_ERR(tu);
485 goto fail_address_parse;
486 }
487 tu->offset = offset;
488 tu->inode = inode;
489 tu->filename = kstrdup(filename, GFP_KERNEL);
490
491 if (!tu->filename) {
492 pr_info("Failed to allocate filename.\n");
493 ret = -ENOMEM;
494 goto error;
495 }
496
497 /* parse arguments */
498 ret = 0;
499 for (i = 0; i < argc && i < MAX_TRACE_ARGS; i++) {
500 struct probe_arg *parg = &tu->tp.args[i];
501
502 /* Increment count for freeing args in error case */
503 tu->tp.nr_args++;
504
505 /* Parse argument name */
506 arg = strchr(argv[i], '=');
507 if (arg) {
508 *arg++ = '\0';
509 parg->name = kstrdup(argv[i], GFP_KERNEL);
510 } else {
511 arg = argv[i];
512 /* If argument name is omitted, set "argN" */
513 snprintf(buf, MAX_EVENT_NAME_LEN, "arg%d", i + 1);
514 parg->name = kstrdup(buf, GFP_KERNEL);
515 }
516
517 if (!parg->name) {
518 pr_info("Failed to allocate argument[%d] name.\n", i);
519 ret = -ENOMEM;
520 goto error;
521 }
522
523 if (!is_good_name(parg->name)) {
524 pr_info("Invalid argument[%d] name: %s\n", i, parg->name);
525 ret = -EINVAL;
526 goto error;
527 }
528
529 if (traceprobe_conflict_field_name(parg->name, tu->tp.args, i)) {
530 pr_info("Argument[%d] name '%s' conflicts with "
531 "another field.\n", i, argv[i]);
532 ret = -EINVAL;
533 goto error;
534 }
535
536 /* Parse fetch argument */
537 ret = traceprobe_parse_probe_arg(arg, &tu->tp.size, parg,
538 is_return, false,
539 uprobes_fetch_type_table);
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
551error:
552 free_trace_uprobe(tu);
553 return ret;
554
555fail_address_parse:
556 iput(inode);
557
558 pr_info("Failed to parse address or file.\n");
559
560 return ret;
561}
562
563static int cleanup_all_probes(void)
564{
565 struct trace_uprobe *tu;
566 int ret = 0;
567
568 mutex_lock(&uprobe_lock);
569 while (!list_empty(&uprobe_list)) {
570 tu = list_entry(uprobe_list.next, struct trace_uprobe, list);
571 ret = unregister_trace_uprobe(tu);
572 if (ret)
573 break;
574 }
575 mutex_unlock(&uprobe_lock);
576 return ret;
577}
578
579/* Probes listing interfaces */
580static void *probes_seq_start(struct seq_file *m, loff_t *pos)
581{
582 mutex_lock(&uprobe_lock);
583 return seq_list_start(&uprobe_list, *pos);
584}
585
586static void *probes_seq_next(struct seq_file *m, void *v, loff_t *pos)
587{
588 return seq_list_next(v, &uprobe_list, pos);
589}
590
591static void probes_seq_stop(struct seq_file *m, void *v)
592{
593 mutex_unlock(&uprobe_lock);
594}
595
596static int probes_seq_show(struct seq_file *m, void *v)
597{
598 struct trace_uprobe *tu = v;
599 char c = is_ret_probe(tu) ? 'r' : 'p';
600 int i;
601
602 seq_printf(m, "%c:%s/%s", c, tu->tp.call.class->system,
603 trace_event_name(&tu->tp.call));
604 seq_printf(m, " %s:", tu->filename);
605
606 /* Don't print "0x (null)" when offset is 0 */
607 if (tu->offset) {
608 seq_printf(m, "0x%p", (void *)tu->offset);
609 } else {
610 switch (sizeof(void *)) {
611 case 4:
612 seq_printf(m, "0x00000000");
613 break;
614 case 8:
615 default:
616 seq_printf(m, "0x0000000000000000");
617 break;
618 }
619 }
620
621 for (i = 0; i < tu->tp.nr_args; i++)
622 seq_printf(m, " %s=%s", tu->tp.args[i].name, tu->tp.args[i].comm);
623
624 seq_putc(m, '\n');
625 return 0;
626}
627
628static const struct seq_operations probes_seq_op = {
629 .start = probes_seq_start,
630 .next = probes_seq_next,
631 .stop = probes_seq_stop,
632 .show = probes_seq_show
633};
634
635static int probes_open(struct inode *inode, struct file *file)
636{
637 int ret;
638
639 if ((file->f_mode & FMODE_WRITE) && (file->f_flags & O_TRUNC)) {
640 ret = cleanup_all_probes();
641 if (ret)
642 return ret;
643 }
644
645 return seq_open(file, &probes_seq_op);
646}
647
648static ssize_t probes_write(struct file *file, const char __user *buffer,
649 size_t count, loff_t *ppos)
650{
651 return traceprobe_probes_write(file, buffer, count, ppos, create_trace_uprobe);
652}
653
654static const struct file_operations uprobe_events_ops = {
655 .owner = THIS_MODULE,
656 .open = probes_open,
657 .read = seq_read,
658 .llseek = seq_lseek,
659 .release = seq_release,
660 .write = probes_write,
661};
662
663/* Probes profiling interfaces */
664static int probes_profile_seq_show(struct seq_file *m, void *v)
665{
666 struct trace_uprobe *tu = v;
667
668 seq_printf(m, " %s %-44s %15lu\n", tu->filename,
669 trace_event_name(&tu->tp.call), tu->nhit);
670 return 0;
671}
672
673static const struct seq_operations profile_seq_op = {
674 .start = probes_seq_start,
675 .next = probes_seq_next,
676 .stop = probes_seq_stop,
677 .show = probes_profile_seq_show
678};
679
680static int profile_open(struct inode *inode, struct file *file)
681{
682 return seq_open(file, &profile_seq_op);
683}
684
685static const struct file_operations uprobe_profile_ops = {
686 .owner = THIS_MODULE,
687 .open = profile_open,
688 .read = seq_read,
689 .llseek = seq_lseek,
690 .release = seq_release,
691};
692
693struct uprobe_cpu_buffer {
694 struct mutex mutex;
695 void *buf;
696};
697static struct uprobe_cpu_buffer __percpu *uprobe_cpu_buffer;
698static int uprobe_buffer_refcnt;
699
700static int uprobe_buffer_init(void)
701{
702 int cpu, err_cpu;
703
704 uprobe_cpu_buffer = alloc_percpu(struct uprobe_cpu_buffer);
705 if (uprobe_cpu_buffer == NULL)
706 return -ENOMEM;
707
708 for_each_possible_cpu(cpu) {
709 struct page *p = alloc_pages_node(cpu_to_node(cpu),
710 GFP_KERNEL, 0);
711 if (p == NULL) {
712 err_cpu = cpu;
713 goto err;
714 }
715 per_cpu_ptr(uprobe_cpu_buffer, cpu)->buf = page_address(p);
716 mutex_init(&per_cpu_ptr(uprobe_cpu_buffer, cpu)->mutex);
717 }
718
719 return 0;
720
721err:
722 for_each_possible_cpu(cpu) {
723 if (cpu == err_cpu)
724 break;
725 free_page((unsigned long)per_cpu_ptr(uprobe_cpu_buffer, cpu)->buf);
726 }
727
728 free_percpu(uprobe_cpu_buffer);
729 return -ENOMEM;
730}
731
732static int uprobe_buffer_enable(void)
733{
734 int ret = 0;
735
736 BUG_ON(!mutex_is_locked(&event_mutex));
737
738 if (uprobe_buffer_refcnt++ == 0) {
739 ret = uprobe_buffer_init();
740 if (ret < 0)
741 uprobe_buffer_refcnt--;
742 }
743
744 return ret;
745}
746
747static void uprobe_buffer_disable(void)
748{
749 int cpu;
750
751 BUG_ON(!mutex_is_locked(&event_mutex));
752
753 if (--uprobe_buffer_refcnt == 0) {
754 for_each_possible_cpu(cpu)
755 free_page((unsigned long)per_cpu_ptr(uprobe_cpu_buffer,
756 cpu)->buf);
757
758 free_percpu(uprobe_cpu_buffer);
759 uprobe_cpu_buffer = NULL;
760 }
761}
762
763static struct uprobe_cpu_buffer *uprobe_buffer_get(void)
764{
765 struct uprobe_cpu_buffer *ucb;
766 int cpu;
767
768 cpu = raw_smp_processor_id();
769 ucb = per_cpu_ptr(uprobe_cpu_buffer, cpu);
770
771 /*
772 * Use per-cpu buffers for fastest access, but we might migrate
773 * so the mutex makes sure we have sole access to it.
774 */
775 mutex_lock(&ucb->mutex);
776
777 return ucb;
778}
779
780static void uprobe_buffer_put(struct uprobe_cpu_buffer *ucb)
781{
782 mutex_unlock(&ucb->mutex);
783}
784
785static void __uprobe_trace_func(struct trace_uprobe *tu,
786 unsigned long func, struct pt_regs *regs,
787 struct uprobe_cpu_buffer *ucb, int dsize,
788 struct trace_event_file *trace_file)
789{
790 struct uprobe_trace_entry_head *entry;
791 struct ring_buffer_event *event;
792 struct ring_buffer *buffer;
793 void *data;
794 int size, esize;
795 struct trace_event_call *call = &tu->tp.call;
796
797 WARN_ON(call != trace_file->event_call);
798
799 if (WARN_ON_ONCE(tu->tp.size + dsize > PAGE_SIZE))
800 return;
801
802 if (trace_trigger_soft_disabled(trace_file))
803 return;
804
805 esize = SIZEOF_TRACE_ENTRY(is_ret_probe(tu));
806 size = esize + tu->tp.size + dsize;
807 event = trace_event_buffer_lock_reserve(&buffer, trace_file,
808 call->event.type, size, 0, 0);
809 if (!event)
810 return;
811
812 entry = ring_buffer_event_data(event);
813 if (is_ret_probe(tu)) {
814 entry->vaddr[0] = func;
815 entry->vaddr[1] = instruction_pointer(regs);
816 data = DATAOF_TRACE_ENTRY(entry, true);
817 } else {
818 entry->vaddr[0] = instruction_pointer(regs);
819 data = DATAOF_TRACE_ENTRY(entry, false);
820 }
821
822 memcpy(data, ucb->buf, tu->tp.size + dsize);
823
824 event_trigger_unlock_commit(trace_file, buffer, event, entry, 0, 0);
825}
826
827/* uprobe handler */
828static int uprobe_trace_func(struct trace_uprobe *tu, struct pt_regs *regs,
829 struct uprobe_cpu_buffer *ucb, int dsize)
830{
831 struct event_file_link *link;
832
833 if (is_ret_probe(tu))
834 return 0;
835
836 rcu_read_lock();
837 list_for_each_entry_rcu(link, &tu->tp.files, list)
838 __uprobe_trace_func(tu, 0, regs, ucb, dsize, link->file);
839 rcu_read_unlock();
840
841 return 0;
842}
843
844static void uretprobe_trace_func(struct trace_uprobe *tu, unsigned long func,
845 struct pt_regs *regs,
846 struct uprobe_cpu_buffer *ucb, int dsize)
847{
848 struct event_file_link *link;
849
850 rcu_read_lock();
851 list_for_each_entry_rcu(link, &tu->tp.files, list)
852 __uprobe_trace_func(tu, func, regs, ucb, dsize, link->file);
853 rcu_read_unlock();
854}
855
856/* Event entry printers */
857static enum print_line_t
858print_uprobe_event(struct trace_iterator *iter, int flags, struct trace_event *event)
859{
860 struct uprobe_trace_entry_head *entry;
861 struct trace_seq *s = &iter->seq;
862 struct trace_uprobe *tu;
863 u8 *data;
864 int i;
865
866 entry = (struct uprobe_trace_entry_head *)iter->ent;
867 tu = container_of(event, struct trace_uprobe, tp.call.event);
868
869 if (is_ret_probe(tu)) {
870 trace_seq_printf(s, "%s: (0x%lx <- 0x%lx)",
871 trace_event_name(&tu->tp.call),
872 entry->vaddr[1], entry->vaddr[0]);
873 data = DATAOF_TRACE_ENTRY(entry, true);
874 } else {
875 trace_seq_printf(s, "%s: (0x%lx)",
876 trace_event_name(&tu->tp.call),
877 entry->vaddr[0]);
878 data = DATAOF_TRACE_ENTRY(entry, false);
879 }
880
881 for (i = 0; i < tu->tp.nr_args; i++) {
882 struct probe_arg *parg = &tu->tp.args[i];
883
884 if (!parg->type->print(s, parg->name, data + parg->offset, entry))
885 goto out;
886 }
887
888 trace_seq_putc(s, '\n');
889
890 out:
891 return trace_handle_return(s);
892}
893
894typedef bool (*filter_func_t)(struct uprobe_consumer *self,
895 enum uprobe_filter_ctx ctx,
896 struct mm_struct *mm);
897
898static int
899probe_event_enable(struct trace_uprobe *tu, struct trace_event_file *file,
900 filter_func_t filter)
901{
902 bool enabled = trace_probe_is_enabled(&tu->tp);
903 struct event_file_link *link = NULL;
904 int ret;
905
906 if (file) {
907 if (tu->tp.flags & TP_FLAG_PROFILE)
908 return -EINTR;
909
910 link = kmalloc(sizeof(*link), GFP_KERNEL);
911 if (!link)
912 return -ENOMEM;
913
914 link->file = file;
915 list_add_tail_rcu(&link->list, &tu->tp.files);
916
917 tu->tp.flags |= TP_FLAG_TRACE;
918 } else {
919 if (tu->tp.flags & TP_FLAG_TRACE)
920 return -EINTR;
921
922 tu->tp.flags |= TP_FLAG_PROFILE;
923 }
924
925 WARN_ON(!uprobe_filter_is_empty(&tu->filter));
926
927 if (enabled)
928 return 0;
929
930 ret = uprobe_buffer_enable();
931 if (ret)
932 goto err_flags;
933
934 tu->consumer.filter = filter;
935 ret = uprobe_register(tu->inode, tu->offset, &tu->consumer);
936 if (ret)
937 goto err_buffer;
938
939 return 0;
940
941 err_buffer:
942 uprobe_buffer_disable();
943
944 err_flags:
945 if (file) {
946 list_del(&link->list);
947 kfree(link);
948 tu->tp.flags &= ~TP_FLAG_TRACE;
949 } else {
950 tu->tp.flags &= ~TP_FLAG_PROFILE;
951 }
952 return ret;
953}
954
955static void
956probe_event_disable(struct trace_uprobe *tu, struct trace_event_file *file)
957{
958 if (!trace_probe_is_enabled(&tu->tp))
959 return;
960
961 if (file) {
962 struct event_file_link *link;
963
964 link = find_event_file_link(&tu->tp, file);
965 if (!link)
966 return;
967
968 list_del_rcu(&link->list);
969 /* synchronize with u{,ret}probe_trace_func */
970 synchronize_sched();
971 kfree(link);
972
973 if (!list_empty(&tu->tp.files))
974 return;
975 }
976
977 WARN_ON(!uprobe_filter_is_empty(&tu->filter));
978
979 uprobe_unregister(tu->inode, tu->offset, &tu->consumer);
980 tu->tp.flags &= file ? ~TP_FLAG_TRACE : ~TP_FLAG_PROFILE;
981
982 uprobe_buffer_disable();
983}
984
985static int uprobe_event_define_fields(struct trace_event_call *event_call)
986{
987 int ret, i, size;
988 struct uprobe_trace_entry_head field;
989 struct trace_uprobe *tu = event_call->data;
990
991 if (is_ret_probe(tu)) {
992 DEFINE_FIELD(unsigned long, vaddr[0], FIELD_STRING_FUNC, 0);
993 DEFINE_FIELD(unsigned long, vaddr[1], FIELD_STRING_RETIP, 0);
994 size = SIZEOF_TRACE_ENTRY(true);
995 } else {
996 DEFINE_FIELD(unsigned long, vaddr[0], FIELD_STRING_IP, 0);
997 size = SIZEOF_TRACE_ENTRY(false);
998 }
999 /* Set argument names as fields */
1000 for (i = 0; i < tu->tp.nr_args; i++) {
1001 struct probe_arg *parg = &tu->tp.args[i];
1002
1003 ret = trace_define_field(event_call, parg->type->fmttype,
1004 parg->name, size + parg->offset,
1005 parg->type->size, parg->type->is_signed,
1006 FILTER_OTHER);
1007
1008 if (ret)
1009 return ret;
1010 }
1011 return 0;
1012}
1013
1014#ifdef CONFIG_PERF_EVENTS
1015static bool
1016__uprobe_perf_filter(struct trace_uprobe_filter *filter, struct mm_struct *mm)
1017{
1018 struct perf_event *event;
1019
1020 if (filter->nr_systemwide)
1021 return true;
1022
1023 list_for_each_entry(event, &filter->perf_events, hw.tp_list) {
1024 if (event->hw.target->mm == mm)
1025 return true;
1026 }
1027
1028 return false;
1029}
1030
1031static inline bool
1032uprobe_filter_event(struct trace_uprobe *tu, struct perf_event *event)
1033{
1034 return __uprobe_perf_filter(&tu->filter, event->hw.target->mm);
1035}
1036
1037static int uprobe_perf_close(struct trace_uprobe *tu, struct perf_event *event)
1038{
1039 bool done;
1040
1041 write_lock(&tu->filter.rwlock);
1042 if (event->hw.target) {
1043 list_del(&event->hw.tp_list);
1044 done = tu->filter.nr_systemwide ||
1045 (event->hw.target->flags & PF_EXITING) ||
1046 uprobe_filter_event(tu, event);
1047 } else {
1048 tu->filter.nr_systemwide--;
1049 done = tu->filter.nr_systemwide;
1050 }
1051 write_unlock(&tu->filter.rwlock);
1052
1053 if (!done)
1054 return uprobe_apply(tu->inode, tu->offset, &tu->consumer, false);
1055
1056 return 0;
1057}
1058
1059static int uprobe_perf_open(struct trace_uprobe *tu, struct perf_event *event)
1060{
1061 bool done;
1062 int err;
1063
1064 write_lock(&tu->filter.rwlock);
1065 if (event->hw.target) {
1066 /*
1067 * event->parent != NULL means copy_process(), we can avoid
1068 * uprobe_apply(). current->mm must be probed and we can rely
1069 * on dup_mmap() which preserves the already installed bp's.
1070 *
1071 * attr.enable_on_exec means that exec/mmap will install the
1072 * breakpoints we need.
1073 */
1074 done = tu->filter.nr_systemwide ||
1075 event->parent || event->attr.enable_on_exec ||
1076 uprobe_filter_event(tu, event);
1077 list_add(&event->hw.tp_list, &tu->filter.perf_events);
1078 } else {
1079 done = tu->filter.nr_systemwide;
1080 tu->filter.nr_systemwide++;
1081 }
1082 write_unlock(&tu->filter.rwlock);
1083
1084 err = 0;
1085 if (!done) {
1086 err = uprobe_apply(tu->inode, tu->offset, &tu->consumer, true);
1087 if (err)
1088 uprobe_perf_close(tu, event);
1089 }
1090 return err;
1091}
1092
1093static bool uprobe_perf_filter(struct uprobe_consumer *uc,
1094 enum uprobe_filter_ctx ctx, struct mm_struct *mm)
1095{
1096 struct trace_uprobe *tu;
1097 int ret;
1098
1099 tu = container_of(uc, struct trace_uprobe, consumer);
1100 read_lock(&tu->filter.rwlock);
1101 ret = __uprobe_perf_filter(&tu->filter, mm);
1102 read_unlock(&tu->filter.rwlock);
1103
1104 return ret;
1105}
1106
1107static void __uprobe_perf_func(struct trace_uprobe *tu,
1108 unsigned long func, struct pt_regs *regs,
1109 struct uprobe_cpu_buffer *ucb, int dsize)
1110{
1111 struct trace_event_call *call = &tu->tp.call;
1112 struct uprobe_trace_entry_head *entry;
1113 struct bpf_prog *prog = call->prog;
1114 struct hlist_head *head;
1115 void *data;
1116 int size, esize;
1117 int rctx;
1118
1119 if (prog && !trace_call_bpf(prog, regs))
1120 return;
1121
1122 esize = SIZEOF_TRACE_ENTRY(is_ret_probe(tu));
1123
1124 size = esize + tu->tp.size + dsize;
1125 size = ALIGN(size + sizeof(u32), sizeof(u64)) - sizeof(u32);
1126 if (WARN_ONCE(size > PERF_MAX_TRACE_SIZE, "profile buffer not large enough"))
1127 return;
1128
1129 preempt_disable();
1130 head = this_cpu_ptr(call->perf_events);
1131 if (hlist_empty(head))
1132 goto out;
1133
1134 entry = perf_trace_buf_prepare(size, call->event.type, NULL, &rctx);
1135 if (!entry)
1136 goto out;
1137
1138 if (is_ret_probe(tu)) {
1139 entry->vaddr[0] = func;
1140 entry->vaddr[1] = instruction_pointer(regs);
1141 data = DATAOF_TRACE_ENTRY(entry, true);
1142 } else {
1143 entry->vaddr[0] = instruction_pointer(regs);
1144 data = DATAOF_TRACE_ENTRY(entry, false);
1145 }
1146
1147 memcpy(data, ucb->buf, tu->tp.size + dsize);
1148
1149 if (size - esize > tu->tp.size + dsize) {
1150 int len = tu->tp.size + dsize;
1151
1152 memset(data + len, 0, size - esize - len);
1153 }
1154
1155 perf_trace_buf_submit(entry, size, rctx, 0, 1, regs, head, NULL);
1156 out:
1157 preempt_enable();
1158}
1159
1160/* uprobe profile handler */
1161static int uprobe_perf_func(struct trace_uprobe *tu, struct pt_regs *regs,
1162 struct uprobe_cpu_buffer *ucb, int dsize)
1163{
1164 if (!uprobe_perf_filter(&tu->consumer, 0, current->mm))
1165 return UPROBE_HANDLER_REMOVE;
1166
1167 if (!is_ret_probe(tu))
1168 __uprobe_perf_func(tu, 0, regs, ucb, dsize);
1169 return 0;
1170}
1171
1172static void uretprobe_perf_func(struct trace_uprobe *tu, unsigned long func,
1173 struct pt_regs *regs,
1174 struct uprobe_cpu_buffer *ucb, int dsize)
1175{
1176 __uprobe_perf_func(tu, func, regs, ucb, dsize);
1177}
1178#endif /* CONFIG_PERF_EVENTS */
1179
1180static int
1181trace_uprobe_register(struct trace_event_call *event, enum trace_reg type,
1182 void *data)
1183{
1184 struct trace_uprobe *tu = event->data;
1185 struct trace_event_file *file = data;
1186
1187 switch (type) {
1188 case TRACE_REG_REGISTER:
1189 return probe_event_enable(tu, file, NULL);
1190
1191 case TRACE_REG_UNREGISTER:
1192 probe_event_disable(tu, file);
1193 return 0;
1194
1195#ifdef CONFIG_PERF_EVENTS
1196 case TRACE_REG_PERF_REGISTER:
1197 return probe_event_enable(tu, NULL, uprobe_perf_filter);
1198
1199 case TRACE_REG_PERF_UNREGISTER:
1200 probe_event_disable(tu, NULL);
1201 return 0;
1202
1203 case TRACE_REG_PERF_OPEN:
1204 return uprobe_perf_open(tu, data);
1205
1206 case TRACE_REG_PERF_CLOSE:
1207 return uprobe_perf_close(tu, data);
1208
1209#endif
1210 default:
1211 return 0;
1212 }
1213 return 0;
1214}
1215
1216static int uprobe_dispatcher(struct uprobe_consumer *con, struct pt_regs *regs)
1217{
1218 struct trace_uprobe *tu;
1219 struct uprobe_dispatch_data udd;
1220 struct uprobe_cpu_buffer *ucb;
1221 int dsize, esize;
1222 int ret = 0;
1223
1224
1225 tu = container_of(con, struct trace_uprobe, consumer);
1226 tu->nhit++;
1227
1228 udd.tu = tu;
1229 udd.bp_addr = instruction_pointer(regs);
1230
1231 current->utask->vaddr = (unsigned long) &udd;
1232
1233 if (WARN_ON_ONCE(!uprobe_cpu_buffer))
1234 return 0;
1235
1236 dsize = __get_data_size(&tu->tp, regs);
1237 esize = SIZEOF_TRACE_ENTRY(is_ret_probe(tu));
1238
1239 ucb = uprobe_buffer_get();
1240 store_trace_args(esize, &tu->tp, regs, ucb->buf, dsize);
1241
1242 if (tu->tp.flags & TP_FLAG_TRACE)
1243 ret |= uprobe_trace_func(tu, regs, ucb, dsize);
1244
1245#ifdef CONFIG_PERF_EVENTS
1246 if (tu->tp.flags & TP_FLAG_PROFILE)
1247 ret |= uprobe_perf_func(tu, regs, ucb, dsize);
1248#endif
1249 uprobe_buffer_put(ucb);
1250 return ret;
1251}
1252
1253static int uretprobe_dispatcher(struct uprobe_consumer *con,
1254 unsigned long func, struct pt_regs *regs)
1255{
1256 struct trace_uprobe *tu;
1257 struct uprobe_dispatch_data udd;
1258 struct uprobe_cpu_buffer *ucb;
1259 int dsize, esize;
1260
1261 tu = container_of(con, struct trace_uprobe, consumer);
1262
1263 udd.tu = tu;
1264 udd.bp_addr = func;
1265
1266 current->utask->vaddr = (unsigned long) &udd;
1267
1268 if (WARN_ON_ONCE(!uprobe_cpu_buffer))
1269 return 0;
1270
1271 dsize = __get_data_size(&tu->tp, regs);
1272 esize = SIZEOF_TRACE_ENTRY(is_ret_probe(tu));
1273
1274 ucb = uprobe_buffer_get();
1275 store_trace_args(esize, &tu->tp, regs, ucb->buf, dsize);
1276
1277 if (tu->tp.flags & TP_FLAG_TRACE)
1278 uretprobe_trace_func(tu, func, regs, ucb, dsize);
1279
1280#ifdef CONFIG_PERF_EVENTS
1281 if (tu->tp.flags & TP_FLAG_PROFILE)
1282 uretprobe_perf_func(tu, func, regs, ucb, dsize);
1283#endif
1284 uprobe_buffer_put(ucb);
1285 return 0;
1286}
1287
1288static struct trace_event_functions uprobe_funcs = {
1289 .trace = print_uprobe_event
1290};
1291
1292static int register_uprobe_event(struct trace_uprobe *tu)
1293{
1294 struct trace_event_call *call = &tu->tp.call;
1295 int ret;
1296
1297 /* Initialize trace_event_call */
1298 INIT_LIST_HEAD(&call->class->fields);
1299 call->event.funcs = &uprobe_funcs;
1300 call->class->define_fields = uprobe_event_define_fields;
1301
1302 if (set_print_fmt(&tu->tp, is_ret_probe(tu)) < 0)
1303 return -ENOMEM;
1304
1305 ret = register_trace_event(&call->event);
1306 if (!ret) {
1307 kfree(call->print_fmt);
1308 return -ENODEV;
1309 }
1310
1311 call->flags = TRACE_EVENT_FL_UPROBE;
1312 call->class->reg = trace_uprobe_register;
1313 call->data = tu;
1314 ret = trace_add_event_call(call);
1315
1316 if (ret) {
1317 pr_info("Failed to register uprobe event: %s\n",
1318 trace_event_name(call));
1319 kfree(call->print_fmt);
1320 unregister_trace_event(&call->event);
1321 }
1322
1323 return ret;
1324}
1325
1326static int unregister_uprobe_event(struct trace_uprobe *tu)
1327{
1328 int ret;
1329
1330 /* tu->event is unregistered in trace_remove_event_call() */
1331 ret = trace_remove_event_call(&tu->tp.call);
1332 if (ret)
1333 return ret;
1334 kfree(tu->tp.call.print_fmt);
1335 tu->tp.call.print_fmt = NULL;
1336 return 0;
1337}
1338
1339/* Make a trace interface for controling probe points */
1340static __init int init_uprobe_trace(void)
1341{
1342 struct dentry *d_tracer;
1343
1344 d_tracer = tracing_init_dentry();
1345 if (IS_ERR(d_tracer))
1346 return 0;
1347
1348 trace_create_file("uprobe_events", 0644, d_tracer,
1349 NULL, &uprobe_events_ops);
1350 /* Profile interface */
1351 trace_create_file("uprobe_profile", 0444, d_tracer,
1352 NULL, &uprobe_profile_ops);
1353 return 0;
1354}
1355
1356fs_initcall(init_uprobe_trace);
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
33struct 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
45struct 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 */
54struct trace_uprobe {
55 struct list_head list;
56 struct trace_uprobe_filter filter;
57 struct uprobe_consumer consumer;
58 struct path path;
59 struct inode *inode;
60 char *filename;
61 unsigned long offset;
62 unsigned long nhit;
63 struct trace_probe tp;
64};
65
66#define SIZEOF_TRACE_UPROBE(n) \
67 (offsetof(struct trace_uprobe, tp.args) + \
68 (sizeof(struct probe_arg) * (n)))
69
70static int register_uprobe_event(struct trace_uprobe *tu);
71static int unregister_uprobe_event(struct trace_uprobe *tu);
72
73static DEFINE_MUTEX(uprobe_lock);
74static LIST_HEAD(uprobe_list);
75
76struct uprobe_dispatch_data {
77 struct trace_uprobe *tu;
78 unsigned long bp_addr;
79};
80
81static int uprobe_dispatcher(struct uprobe_consumer *con, struct pt_regs *regs);
82static int uretprobe_dispatcher(struct uprobe_consumer *con,
83 unsigned long func, struct pt_regs *regs);
84
85#ifdef CONFIG_STACK_GROWSUP
86static unsigned long adjust_stack_addr(unsigned long addr, unsigned int n)
87{
88 return addr - (n * sizeof(long));
89}
90#else
91static unsigned long adjust_stack_addr(unsigned long addr, unsigned int n)
92{
93 return addr + (n * sizeof(long));
94}
95#endif
96
97static unsigned long get_user_stack_nth(struct pt_regs *regs, unsigned int n)
98{
99 unsigned long ret;
100 unsigned long addr = user_stack_pointer(regs);
101
102 addr = adjust_stack_addr(addr, n);
103
104 if (copy_from_user(&ret, (void __force __user *) addr, sizeof(ret)))
105 return 0;
106
107 return ret;
108}
109
110/*
111 * Uprobes-specific fetch functions
112 */
113#define DEFINE_FETCH_stack(type) \
114static void FETCH_FUNC_NAME(stack, type)(struct pt_regs *regs, \
115 void *offset, void *dest) \
116{ \
117 *(type *)dest = (type)get_user_stack_nth(regs, \
118 ((unsigned long)offset)); \
119}
120DEFINE_BASIC_FETCH_FUNCS(stack)
121/* No string on the stack entry */
122#define fetch_stack_string NULL
123#define fetch_stack_string_size NULL
124
125#define DEFINE_FETCH_memory(type) \
126static void FETCH_FUNC_NAME(memory, type)(struct pt_regs *regs, \
127 void *addr, void *dest) \
128{ \
129 type retval; \
130 void __user *vaddr = (void __force __user *) addr; \
131 \
132 if (copy_from_user(&retval, vaddr, sizeof(type))) \
133 *(type *)dest = 0; \
134 else \
135 *(type *) dest = retval; \
136}
137DEFINE_BASIC_FETCH_FUNCS(memory)
138/*
139 * Fetch a null-terminated string. Caller MUST set *(u32 *)dest with max
140 * length and relative data location.
141 */
142static void FETCH_FUNC_NAME(memory, string)(struct pt_regs *regs,
143 void *addr, void *dest)
144{
145 long ret;
146 u32 rloc = *(u32 *)dest;
147 int maxlen = get_rloc_len(rloc);
148 u8 *dst = get_rloc_data(dest);
149 void __user *src = (void __force __user *) addr;
150
151 if (!maxlen)
152 return;
153
154 ret = strncpy_from_user(dst, src, maxlen);
155 if (ret == maxlen)
156 dst[--ret] = '\0';
157
158 if (ret < 0) { /* Failed to fetch string */
159 ((u8 *)get_rloc_data(dest))[0] = '\0';
160 *(u32 *)dest = make_data_rloc(0, get_rloc_offs(rloc));
161 } else {
162 *(u32 *)dest = make_data_rloc(ret, get_rloc_offs(rloc));
163 }
164}
165
166static void FETCH_FUNC_NAME(memory, string_size)(struct pt_regs *regs,
167 void *addr, void *dest)
168{
169 int len;
170 void __user *vaddr = (void __force __user *) addr;
171
172 len = strnlen_user(vaddr, MAX_STRING_SIZE);
173
174 if (len == 0 || len > MAX_STRING_SIZE) /* Failed to check length */
175 *(u32 *)dest = 0;
176 else
177 *(u32 *)dest = len;
178}
179
180static unsigned long translate_user_vaddr(void *file_offset)
181{
182 unsigned long base_addr;
183 struct uprobe_dispatch_data *udd;
184
185 udd = (void *) current->utask->vaddr;
186
187 base_addr = udd->bp_addr - udd->tu->offset;
188 return base_addr + (unsigned long)file_offset;
189}
190
191#define DEFINE_FETCH_file_offset(type) \
192static void FETCH_FUNC_NAME(file_offset, type)(struct pt_regs *regs, \
193 void *offset, void *dest)\
194{ \
195 void *vaddr = (void *)translate_user_vaddr(offset); \
196 \
197 FETCH_FUNC_NAME(memory, type)(regs, vaddr, dest); \
198}
199DEFINE_BASIC_FETCH_FUNCS(file_offset)
200DEFINE_FETCH_file_offset(string)
201DEFINE_FETCH_file_offset(string_size)
202
203/* Fetch type information table */
204static const struct fetch_type uprobes_fetch_type_table[] = {
205 /* Special types */
206 [FETCH_TYPE_STRING] = __ASSIGN_FETCH_TYPE("string", string, string,
207 sizeof(u32), 1, "__data_loc char[]"),
208 [FETCH_TYPE_STRSIZE] = __ASSIGN_FETCH_TYPE("string_size", u32,
209 string_size, sizeof(u32), 0, "u32"),
210 /* Basic types */
211 ASSIGN_FETCH_TYPE(u8, u8, 0),
212 ASSIGN_FETCH_TYPE(u16, u16, 0),
213 ASSIGN_FETCH_TYPE(u32, u32, 0),
214 ASSIGN_FETCH_TYPE(u64, u64, 0),
215 ASSIGN_FETCH_TYPE(s8, u8, 1),
216 ASSIGN_FETCH_TYPE(s16, u16, 1),
217 ASSIGN_FETCH_TYPE(s32, u32, 1),
218 ASSIGN_FETCH_TYPE(s64, u64, 1),
219 ASSIGN_FETCH_TYPE_ALIAS(x8, u8, u8, 0),
220 ASSIGN_FETCH_TYPE_ALIAS(x16, u16, u16, 0),
221 ASSIGN_FETCH_TYPE_ALIAS(x32, u32, u32, 0),
222 ASSIGN_FETCH_TYPE_ALIAS(x64, u64, u64, 0),
223
224 ASSIGN_FETCH_TYPE_END
225};
226
227static inline void init_trace_uprobe_filter(struct trace_uprobe_filter *filter)
228{
229 rwlock_init(&filter->rwlock);
230 filter->nr_systemwide = 0;
231 INIT_LIST_HEAD(&filter->perf_events);
232}
233
234static inline bool uprobe_filter_is_empty(struct trace_uprobe_filter *filter)
235{
236 return !filter->nr_systemwide && list_empty(&filter->perf_events);
237}
238
239static inline bool is_ret_probe(struct trace_uprobe *tu)
240{
241 return tu->consumer.ret_handler != NULL;
242}
243
244/*
245 * Allocate new trace_uprobe and initialize it (including uprobes).
246 */
247static struct trace_uprobe *
248alloc_trace_uprobe(const char *group, const char *event, int nargs, bool is_ret)
249{
250 struct trace_uprobe *tu;
251
252 if (!event || !is_good_name(event))
253 return ERR_PTR(-EINVAL);
254
255 if (!group || !is_good_name(group))
256 return ERR_PTR(-EINVAL);
257
258 tu = kzalloc(SIZEOF_TRACE_UPROBE(nargs), GFP_KERNEL);
259 if (!tu)
260 return ERR_PTR(-ENOMEM);
261
262 tu->tp.call.class = &tu->tp.class;
263 tu->tp.call.name = kstrdup(event, GFP_KERNEL);
264 if (!tu->tp.call.name)
265 goto error;
266
267 tu->tp.class.system = kstrdup(group, GFP_KERNEL);
268 if (!tu->tp.class.system)
269 goto error;
270
271 INIT_LIST_HEAD(&tu->list);
272 INIT_LIST_HEAD(&tu->tp.files);
273 tu->consumer.handler = uprobe_dispatcher;
274 if (is_ret)
275 tu->consumer.ret_handler = uretprobe_dispatcher;
276 init_trace_uprobe_filter(&tu->filter);
277 return tu;
278
279error:
280 kfree(tu->tp.call.name);
281 kfree(tu);
282
283 return ERR_PTR(-ENOMEM);
284}
285
286static void free_trace_uprobe(struct trace_uprobe *tu)
287{
288 int i;
289
290 for (i = 0; i < tu->tp.nr_args; i++)
291 traceprobe_free_probe_arg(&tu->tp.args[i]);
292
293 path_put(&tu->path);
294 kfree(tu->tp.call.class->system);
295 kfree(tu->tp.call.name);
296 kfree(tu->filename);
297 kfree(tu);
298}
299
300static struct trace_uprobe *find_probe_event(const char *event, const char *group)
301{
302 struct trace_uprobe *tu;
303
304 list_for_each_entry(tu, &uprobe_list, list)
305 if (strcmp(trace_event_name(&tu->tp.call), event) == 0 &&
306 strcmp(tu->tp.call.class->system, group) == 0)
307 return tu;
308
309 return NULL;
310}
311
312/* Unregister a trace_uprobe and probe_event: call with locking uprobe_lock */
313static int unregister_trace_uprobe(struct trace_uprobe *tu)
314{
315 int ret;
316
317 ret = unregister_uprobe_event(tu);
318 if (ret)
319 return ret;
320
321 list_del(&tu->list);
322 free_trace_uprobe(tu);
323 return 0;
324}
325
326/* Register a trace_uprobe and probe_event */
327static int register_trace_uprobe(struct trace_uprobe *tu)
328{
329 struct trace_uprobe *old_tu;
330 int ret;
331
332 mutex_lock(&uprobe_lock);
333
334 /* register as an event */
335 old_tu = find_probe_event(trace_event_name(&tu->tp.call),
336 tu->tp.call.class->system);
337 if (old_tu) {
338 /* delete old event */
339 ret = unregister_trace_uprobe(old_tu);
340 if (ret)
341 goto end;
342 }
343
344 ret = register_uprobe_event(tu);
345 if (ret) {
346 pr_warn("Failed to register probe event(%d)\n", ret);
347 goto end;
348 }
349
350 list_add_tail(&tu->list, &uprobe_list);
351
352end:
353 mutex_unlock(&uprobe_lock);
354
355 return ret;
356}
357
358/*
359 * Argument syntax:
360 * - Add uprobe: p|r[:[GRP/]EVENT] PATH:OFFSET [FETCHARGS]
361 *
362 * - Remove uprobe: -:[GRP/]EVENT
363 */
364static int create_trace_uprobe(int argc, char **argv)
365{
366 struct trace_uprobe *tu;
367 char *arg, *event, *group, *filename;
368 char buf[MAX_EVENT_NAME_LEN];
369 struct path path;
370 unsigned long offset;
371 bool is_delete, is_return;
372 int i, ret;
373
374 ret = 0;
375 is_delete = false;
376 is_return = false;
377 event = NULL;
378 group = NULL;
379
380 /* argc must be >= 1 */
381 if (argv[0][0] == '-')
382 is_delete = true;
383 else if (argv[0][0] == 'r')
384 is_return = true;
385 else if (argv[0][0] != 'p') {
386 pr_info("Probe definition must be started with 'p', 'r' or '-'.\n");
387 return -EINVAL;
388 }
389
390 if (argv[0][1] == ':') {
391 event = &argv[0][2];
392 arg = strchr(event, '/');
393
394 if (arg) {
395 group = event;
396 event = arg + 1;
397 event[-1] = '\0';
398
399 if (strlen(group) == 0) {
400 pr_info("Group name is not specified\n");
401 return -EINVAL;
402 }
403 }
404 if (strlen(event) == 0) {
405 pr_info("Event name is not specified\n");
406 return -EINVAL;
407 }
408 }
409 if (!group)
410 group = UPROBE_EVENT_SYSTEM;
411
412 if (is_delete) {
413 int ret;
414
415 if (!event) {
416 pr_info("Delete command needs an event name.\n");
417 return -EINVAL;
418 }
419 mutex_lock(&uprobe_lock);
420 tu = find_probe_event(event, group);
421
422 if (!tu) {
423 mutex_unlock(&uprobe_lock);
424 pr_info("Event %s/%s doesn't exist.\n", group, event);
425 return -ENOENT;
426 }
427 /* delete an event */
428 ret = unregister_trace_uprobe(tu);
429 mutex_unlock(&uprobe_lock);
430 return ret;
431 }
432
433 if (argc < 2) {
434 pr_info("Probe point is not specified.\n");
435 return -EINVAL;
436 }
437 /* Find the last occurrence, in case the path contains ':' too. */
438 arg = strrchr(argv[1], ':');
439 if (!arg)
440 return -EINVAL;
441
442 *arg++ = '\0';
443 filename = argv[1];
444 ret = kern_path(filename, LOOKUP_FOLLOW, &path);
445 if (ret)
446 return ret;
447
448 if (!d_is_reg(path.dentry)) {
449 ret = -EINVAL;
450 goto fail_address_parse;
451 }
452
453 ret = kstrtoul(arg, 0, &offset);
454 if (ret)
455 goto fail_address_parse;
456
457 argc -= 2;
458 argv += 2;
459
460 /* setup a probe */
461 if (!event) {
462 char *tail;
463 char *ptr;
464
465 tail = kstrdup(kbasename(filename), GFP_KERNEL);
466 if (!tail) {
467 ret = -ENOMEM;
468 goto fail_address_parse;
469 }
470
471 ptr = strpbrk(tail, ".-_");
472 if (ptr)
473 *ptr = '\0';
474
475 snprintf(buf, MAX_EVENT_NAME_LEN, "%c_%s_0x%lx", 'p', tail, offset);
476 event = buf;
477 kfree(tail);
478 }
479
480 tu = alloc_trace_uprobe(group, event, argc, is_return);
481 if (IS_ERR(tu)) {
482 pr_info("Failed to allocate trace_uprobe.(%d)\n", (int)PTR_ERR(tu));
483 ret = PTR_ERR(tu);
484 goto fail_address_parse;
485 }
486 tu->offset = offset;
487 tu->path = path;
488 tu->filename = kstrdup(filename, GFP_KERNEL);
489
490 if (!tu->filename) {
491 pr_info("Failed to allocate filename.\n");
492 ret = -ENOMEM;
493 goto error;
494 }
495
496 /* parse arguments */
497 ret = 0;
498 for (i = 0; i < argc && i < MAX_TRACE_ARGS; i++) {
499 struct probe_arg *parg = &tu->tp.args[i];
500
501 /* Increment count for freeing args in error case */
502 tu->tp.nr_args++;
503
504 /* Parse argument name */
505 arg = strchr(argv[i], '=');
506 if (arg) {
507 *arg++ = '\0';
508 parg->name = kstrdup(argv[i], GFP_KERNEL);
509 } else {
510 arg = argv[i];
511 /* If argument name is omitted, set "argN" */
512 snprintf(buf, MAX_EVENT_NAME_LEN, "arg%d", i + 1);
513 parg->name = kstrdup(buf, GFP_KERNEL);
514 }
515
516 if (!parg->name) {
517 pr_info("Failed to allocate argument[%d] name.\n", i);
518 ret = -ENOMEM;
519 goto error;
520 }
521
522 if (!is_good_name(parg->name)) {
523 pr_info("Invalid argument[%d] name: %s\n", i, parg->name);
524 ret = -EINVAL;
525 goto error;
526 }
527
528 if (traceprobe_conflict_field_name(parg->name, tu->tp.args, i)) {
529 pr_info("Argument[%d] name '%s' conflicts with "
530 "another field.\n", i, argv[i]);
531 ret = -EINVAL;
532 goto error;
533 }
534
535 /* Parse fetch argument */
536 ret = traceprobe_parse_probe_arg(arg, &tu->tp.size, parg,
537 is_return, false,
538 uprobes_fetch_type_table);
539 if (ret) {
540 pr_info("Parse error at argument[%d]. (%d)\n", i, ret);
541 goto error;
542 }
543 }
544
545 ret = register_trace_uprobe(tu);
546 if (ret)
547 goto error;
548 return 0;
549
550error:
551 free_trace_uprobe(tu);
552 return ret;
553
554fail_address_parse:
555 path_put(&path);
556
557 pr_info("Failed to parse address or file.\n");
558
559 return ret;
560}
561
562static int cleanup_all_probes(void)
563{
564 struct trace_uprobe *tu;
565 int ret = 0;
566
567 mutex_lock(&uprobe_lock);
568 while (!list_empty(&uprobe_list)) {
569 tu = list_entry(uprobe_list.next, struct trace_uprobe, list);
570 ret = unregister_trace_uprobe(tu);
571 if (ret)
572 break;
573 }
574 mutex_unlock(&uprobe_lock);
575 return ret;
576}
577
578/* Probes listing interfaces */
579static void *probes_seq_start(struct seq_file *m, loff_t *pos)
580{
581 mutex_lock(&uprobe_lock);
582 return seq_list_start(&uprobe_list, *pos);
583}
584
585static void *probes_seq_next(struct seq_file *m, void *v, loff_t *pos)
586{
587 return seq_list_next(v, &uprobe_list, pos);
588}
589
590static void probes_seq_stop(struct seq_file *m, void *v)
591{
592 mutex_unlock(&uprobe_lock);
593}
594
595static int probes_seq_show(struct seq_file *m, void *v)
596{
597 struct trace_uprobe *tu = v;
598 char c = is_ret_probe(tu) ? 'r' : 'p';
599 int i;
600
601 seq_printf(m, "%c:%s/%s %s:0x%0*lx", c, tu->tp.call.class->system,
602 trace_event_name(&tu->tp.call), tu->filename,
603 (int)(sizeof(void *) * 2), tu->offset);
604
605 for (i = 0; i < tu->tp.nr_args; i++)
606 seq_printf(m, " %s=%s", tu->tp.args[i].name, tu->tp.args[i].comm);
607
608 seq_putc(m, '\n');
609 return 0;
610}
611
612static const struct seq_operations probes_seq_op = {
613 .start = probes_seq_start,
614 .next = probes_seq_next,
615 .stop = probes_seq_stop,
616 .show = probes_seq_show
617};
618
619static int probes_open(struct inode *inode, struct file *file)
620{
621 int ret;
622
623 if ((file->f_mode & FMODE_WRITE) && (file->f_flags & O_TRUNC)) {
624 ret = cleanup_all_probes();
625 if (ret)
626 return ret;
627 }
628
629 return seq_open(file, &probes_seq_op);
630}
631
632static ssize_t probes_write(struct file *file, const char __user *buffer,
633 size_t count, loff_t *ppos)
634{
635 return trace_parse_run_command(file, buffer, count, ppos, create_trace_uprobe);
636}
637
638static const struct file_operations uprobe_events_ops = {
639 .owner = THIS_MODULE,
640 .open = probes_open,
641 .read = seq_read,
642 .llseek = seq_lseek,
643 .release = seq_release,
644 .write = probes_write,
645};
646
647/* Probes profiling interfaces */
648static int probes_profile_seq_show(struct seq_file *m, void *v)
649{
650 struct trace_uprobe *tu = v;
651
652 seq_printf(m, " %s %-44s %15lu\n", tu->filename,
653 trace_event_name(&tu->tp.call), tu->nhit);
654 return 0;
655}
656
657static const struct seq_operations profile_seq_op = {
658 .start = probes_seq_start,
659 .next = probes_seq_next,
660 .stop = probes_seq_stop,
661 .show = probes_profile_seq_show
662};
663
664static int profile_open(struct inode *inode, struct file *file)
665{
666 return seq_open(file, &profile_seq_op);
667}
668
669static const struct file_operations uprobe_profile_ops = {
670 .owner = THIS_MODULE,
671 .open = profile_open,
672 .read = seq_read,
673 .llseek = seq_lseek,
674 .release = seq_release,
675};
676
677struct uprobe_cpu_buffer {
678 struct mutex mutex;
679 void *buf;
680};
681static struct uprobe_cpu_buffer __percpu *uprobe_cpu_buffer;
682static int uprobe_buffer_refcnt;
683
684static int uprobe_buffer_init(void)
685{
686 int cpu, err_cpu;
687
688 uprobe_cpu_buffer = alloc_percpu(struct uprobe_cpu_buffer);
689 if (uprobe_cpu_buffer == NULL)
690 return -ENOMEM;
691
692 for_each_possible_cpu(cpu) {
693 struct page *p = alloc_pages_node(cpu_to_node(cpu),
694 GFP_KERNEL, 0);
695 if (p == NULL) {
696 err_cpu = cpu;
697 goto err;
698 }
699 per_cpu_ptr(uprobe_cpu_buffer, cpu)->buf = page_address(p);
700 mutex_init(&per_cpu_ptr(uprobe_cpu_buffer, cpu)->mutex);
701 }
702
703 return 0;
704
705err:
706 for_each_possible_cpu(cpu) {
707 if (cpu == err_cpu)
708 break;
709 free_page((unsigned long)per_cpu_ptr(uprobe_cpu_buffer, cpu)->buf);
710 }
711
712 free_percpu(uprobe_cpu_buffer);
713 return -ENOMEM;
714}
715
716static int uprobe_buffer_enable(void)
717{
718 int ret = 0;
719
720 BUG_ON(!mutex_is_locked(&event_mutex));
721
722 if (uprobe_buffer_refcnt++ == 0) {
723 ret = uprobe_buffer_init();
724 if (ret < 0)
725 uprobe_buffer_refcnt--;
726 }
727
728 return ret;
729}
730
731static void uprobe_buffer_disable(void)
732{
733 int cpu;
734
735 BUG_ON(!mutex_is_locked(&event_mutex));
736
737 if (--uprobe_buffer_refcnt == 0) {
738 for_each_possible_cpu(cpu)
739 free_page((unsigned long)per_cpu_ptr(uprobe_cpu_buffer,
740 cpu)->buf);
741
742 free_percpu(uprobe_cpu_buffer);
743 uprobe_cpu_buffer = NULL;
744 }
745}
746
747static struct uprobe_cpu_buffer *uprobe_buffer_get(void)
748{
749 struct uprobe_cpu_buffer *ucb;
750 int cpu;
751
752 cpu = raw_smp_processor_id();
753 ucb = per_cpu_ptr(uprobe_cpu_buffer, cpu);
754
755 /*
756 * Use per-cpu buffers for fastest access, but we might migrate
757 * so the mutex makes sure we have sole access to it.
758 */
759 mutex_lock(&ucb->mutex);
760
761 return ucb;
762}
763
764static void uprobe_buffer_put(struct uprobe_cpu_buffer *ucb)
765{
766 mutex_unlock(&ucb->mutex);
767}
768
769static void __uprobe_trace_func(struct trace_uprobe *tu,
770 unsigned long func, struct pt_regs *regs,
771 struct uprobe_cpu_buffer *ucb, int dsize,
772 struct trace_event_file *trace_file)
773{
774 struct uprobe_trace_entry_head *entry;
775 struct ring_buffer_event *event;
776 struct ring_buffer *buffer;
777 void *data;
778 int size, esize;
779 struct trace_event_call *call = &tu->tp.call;
780
781 WARN_ON(call != trace_file->event_call);
782
783 if (WARN_ON_ONCE(tu->tp.size + dsize > PAGE_SIZE))
784 return;
785
786 if (trace_trigger_soft_disabled(trace_file))
787 return;
788
789 esize = SIZEOF_TRACE_ENTRY(is_ret_probe(tu));
790 size = esize + tu->tp.size + dsize;
791 event = trace_event_buffer_lock_reserve(&buffer, trace_file,
792 call->event.type, size, 0, 0);
793 if (!event)
794 return;
795
796 entry = ring_buffer_event_data(event);
797 if (is_ret_probe(tu)) {
798 entry->vaddr[0] = func;
799 entry->vaddr[1] = instruction_pointer(regs);
800 data = DATAOF_TRACE_ENTRY(entry, true);
801 } else {
802 entry->vaddr[0] = instruction_pointer(regs);
803 data = DATAOF_TRACE_ENTRY(entry, false);
804 }
805
806 memcpy(data, ucb->buf, tu->tp.size + dsize);
807
808 event_trigger_unlock_commit(trace_file, buffer, event, entry, 0, 0);
809}
810
811/* uprobe handler */
812static int uprobe_trace_func(struct trace_uprobe *tu, struct pt_regs *regs,
813 struct uprobe_cpu_buffer *ucb, int dsize)
814{
815 struct event_file_link *link;
816
817 if (is_ret_probe(tu))
818 return 0;
819
820 rcu_read_lock();
821 list_for_each_entry_rcu(link, &tu->tp.files, list)
822 __uprobe_trace_func(tu, 0, regs, ucb, dsize, link->file);
823 rcu_read_unlock();
824
825 return 0;
826}
827
828static void uretprobe_trace_func(struct trace_uprobe *tu, unsigned long func,
829 struct pt_regs *regs,
830 struct uprobe_cpu_buffer *ucb, int dsize)
831{
832 struct event_file_link *link;
833
834 rcu_read_lock();
835 list_for_each_entry_rcu(link, &tu->tp.files, list)
836 __uprobe_trace_func(tu, func, regs, ucb, dsize, link->file);
837 rcu_read_unlock();
838}
839
840/* Event entry printers */
841static enum print_line_t
842print_uprobe_event(struct trace_iterator *iter, int flags, struct trace_event *event)
843{
844 struct uprobe_trace_entry_head *entry;
845 struct trace_seq *s = &iter->seq;
846 struct trace_uprobe *tu;
847 u8 *data;
848 int i;
849
850 entry = (struct uprobe_trace_entry_head *)iter->ent;
851 tu = container_of(event, struct trace_uprobe, tp.call.event);
852
853 if (is_ret_probe(tu)) {
854 trace_seq_printf(s, "%s: (0x%lx <- 0x%lx)",
855 trace_event_name(&tu->tp.call),
856 entry->vaddr[1], entry->vaddr[0]);
857 data = DATAOF_TRACE_ENTRY(entry, true);
858 } else {
859 trace_seq_printf(s, "%s: (0x%lx)",
860 trace_event_name(&tu->tp.call),
861 entry->vaddr[0]);
862 data = DATAOF_TRACE_ENTRY(entry, false);
863 }
864
865 for (i = 0; i < tu->tp.nr_args; i++) {
866 struct probe_arg *parg = &tu->tp.args[i];
867
868 if (!parg->type->print(s, parg->name, data + parg->offset, entry))
869 goto out;
870 }
871
872 trace_seq_putc(s, '\n');
873
874 out:
875 return trace_handle_return(s);
876}
877
878typedef bool (*filter_func_t)(struct uprobe_consumer *self,
879 enum uprobe_filter_ctx ctx,
880 struct mm_struct *mm);
881
882static int
883probe_event_enable(struct trace_uprobe *tu, struct trace_event_file *file,
884 filter_func_t filter)
885{
886 bool enabled = trace_probe_is_enabled(&tu->tp);
887 struct event_file_link *link = NULL;
888 int ret;
889
890 if (file) {
891 if (tu->tp.flags & TP_FLAG_PROFILE)
892 return -EINTR;
893
894 link = kmalloc(sizeof(*link), GFP_KERNEL);
895 if (!link)
896 return -ENOMEM;
897
898 link->file = file;
899 list_add_tail_rcu(&link->list, &tu->tp.files);
900
901 tu->tp.flags |= TP_FLAG_TRACE;
902 } else {
903 if (tu->tp.flags & TP_FLAG_TRACE)
904 return -EINTR;
905
906 tu->tp.flags |= TP_FLAG_PROFILE;
907 }
908
909 WARN_ON(!uprobe_filter_is_empty(&tu->filter));
910
911 if (enabled)
912 return 0;
913
914 ret = uprobe_buffer_enable();
915 if (ret)
916 goto err_flags;
917
918 tu->consumer.filter = filter;
919 tu->inode = d_real_inode(tu->path.dentry);
920 ret = uprobe_register(tu->inode, tu->offset, &tu->consumer);
921 if (ret)
922 goto err_buffer;
923
924 return 0;
925
926 err_buffer:
927 uprobe_buffer_disable();
928
929 err_flags:
930 if (file) {
931 list_del(&link->list);
932 kfree(link);
933 tu->tp.flags &= ~TP_FLAG_TRACE;
934 } else {
935 tu->tp.flags &= ~TP_FLAG_PROFILE;
936 }
937 return ret;
938}
939
940static void
941probe_event_disable(struct trace_uprobe *tu, struct trace_event_file *file)
942{
943 if (!trace_probe_is_enabled(&tu->tp))
944 return;
945
946 if (file) {
947 struct event_file_link *link;
948
949 link = find_event_file_link(&tu->tp, file);
950 if (!link)
951 return;
952
953 list_del_rcu(&link->list);
954 /* synchronize with u{,ret}probe_trace_func */
955 synchronize_sched();
956 kfree(link);
957
958 if (!list_empty(&tu->tp.files))
959 return;
960 }
961
962 WARN_ON(!uprobe_filter_is_empty(&tu->filter));
963
964 uprobe_unregister(tu->inode, tu->offset, &tu->consumer);
965 tu->inode = NULL;
966 tu->tp.flags &= file ? ~TP_FLAG_TRACE : ~TP_FLAG_PROFILE;
967
968 uprobe_buffer_disable();
969}
970
971static int uprobe_event_define_fields(struct trace_event_call *event_call)
972{
973 int ret, i, size;
974 struct uprobe_trace_entry_head field;
975 struct trace_uprobe *tu = event_call->data;
976
977 if (is_ret_probe(tu)) {
978 DEFINE_FIELD(unsigned long, vaddr[0], FIELD_STRING_FUNC, 0);
979 DEFINE_FIELD(unsigned long, vaddr[1], FIELD_STRING_RETIP, 0);
980 size = SIZEOF_TRACE_ENTRY(true);
981 } else {
982 DEFINE_FIELD(unsigned long, vaddr[0], FIELD_STRING_IP, 0);
983 size = SIZEOF_TRACE_ENTRY(false);
984 }
985 /* Set argument names as fields */
986 for (i = 0; i < tu->tp.nr_args; i++) {
987 struct probe_arg *parg = &tu->tp.args[i];
988
989 ret = trace_define_field(event_call, parg->type->fmttype,
990 parg->name, size + parg->offset,
991 parg->type->size, parg->type->is_signed,
992 FILTER_OTHER);
993
994 if (ret)
995 return ret;
996 }
997 return 0;
998}
999
1000#ifdef CONFIG_PERF_EVENTS
1001static bool
1002__uprobe_perf_filter(struct trace_uprobe_filter *filter, struct mm_struct *mm)
1003{
1004 struct perf_event *event;
1005
1006 if (filter->nr_systemwide)
1007 return true;
1008
1009 list_for_each_entry(event, &filter->perf_events, hw.tp_list) {
1010 if (event->hw.target->mm == mm)
1011 return true;
1012 }
1013
1014 return false;
1015}
1016
1017static inline bool
1018uprobe_filter_event(struct trace_uprobe *tu, struct perf_event *event)
1019{
1020 return __uprobe_perf_filter(&tu->filter, event->hw.target->mm);
1021}
1022
1023static int uprobe_perf_close(struct trace_uprobe *tu, struct perf_event *event)
1024{
1025 bool done;
1026
1027 write_lock(&tu->filter.rwlock);
1028 if (event->hw.target) {
1029 list_del(&event->hw.tp_list);
1030 done = tu->filter.nr_systemwide ||
1031 (event->hw.target->flags & PF_EXITING) ||
1032 uprobe_filter_event(tu, event);
1033 } else {
1034 tu->filter.nr_systemwide--;
1035 done = tu->filter.nr_systemwide;
1036 }
1037 write_unlock(&tu->filter.rwlock);
1038
1039 if (!done)
1040 return uprobe_apply(tu->inode, tu->offset, &tu->consumer, false);
1041
1042 return 0;
1043}
1044
1045static int uprobe_perf_open(struct trace_uprobe *tu, struct perf_event *event)
1046{
1047 bool done;
1048 int err;
1049
1050 write_lock(&tu->filter.rwlock);
1051 if (event->hw.target) {
1052 /*
1053 * event->parent != NULL means copy_process(), we can avoid
1054 * uprobe_apply(). current->mm must be probed and we can rely
1055 * on dup_mmap() which preserves the already installed bp's.
1056 *
1057 * attr.enable_on_exec means that exec/mmap will install the
1058 * breakpoints we need.
1059 */
1060 done = tu->filter.nr_systemwide ||
1061 event->parent || event->attr.enable_on_exec ||
1062 uprobe_filter_event(tu, event);
1063 list_add(&event->hw.tp_list, &tu->filter.perf_events);
1064 } else {
1065 done = tu->filter.nr_systemwide;
1066 tu->filter.nr_systemwide++;
1067 }
1068 write_unlock(&tu->filter.rwlock);
1069
1070 err = 0;
1071 if (!done) {
1072 err = uprobe_apply(tu->inode, tu->offset, &tu->consumer, true);
1073 if (err)
1074 uprobe_perf_close(tu, event);
1075 }
1076 return err;
1077}
1078
1079static bool uprobe_perf_filter(struct uprobe_consumer *uc,
1080 enum uprobe_filter_ctx ctx, struct mm_struct *mm)
1081{
1082 struct trace_uprobe *tu;
1083 int ret;
1084
1085 tu = container_of(uc, struct trace_uprobe, consumer);
1086 read_lock(&tu->filter.rwlock);
1087 ret = __uprobe_perf_filter(&tu->filter, mm);
1088 read_unlock(&tu->filter.rwlock);
1089
1090 return ret;
1091}
1092
1093static void __uprobe_perf_func(struct trace_uprobe *tu,
1094 unsigned long func, struct pt_regs *regs,
1095 struct uprobe_cpu_buffer *ucb, int dsize)
1096{
1097 struct trace_event_call *call = &tu->tp.call;
1098 struct uprobe_trace_entry_head *entry;
1099 struct hlist_head *head;
1100 void *data;
1101 int size, esize;
1102 int rctx;
1103
1104 if (bpf_prog_array_valid(call) && !trace_call_bpf(call, regs))
1105 return;
1106
1107 esize = SIZEOF_TRACE_ENTRY(is_ret_probe(tu));
1108
1109 size = esize + tu->tp.size + dsize;
1110 size = ALIGN(size + sizeof(u32), sizeof(u64)) - sizeof(u32);
1111 if (WARN_ONCE(size > PERF_MAX_TRACE_SIZE, "profile buffer not large enough"))
1112 return;
1113
1114 preempt_disable();
1115 head = this_cpu_ptr(call->perf_events);
1116 if (hlist_empty(head))
1117 goto out;
1118
1119 entry = perf_trace_buf_alloc(size, NULL, &rctx);
1120 if (!entry)
1121 goto out;
1122
1123 if (is_ret_probe(tu)) {
1124 entry->vaddr[0] = func;
1125 entry->vaddr[1] = instruction_pointer(regs);
1126 data = DATAOF_TRACE_ENTRY(entry, true);
1127 } else {
1128 entry->vaddr[0] = instruction_pointer(regs);
1129 data = DATAOF_TRACE_ENTRY(entry, false);
1130 }
1131
1132 memcpy(data, ucb->buf, tu->tp.size + dsize);
1133
1134 if (size - esize > tu->tp.size + dsize) {
1135 int len = tu->tp.size + dsize;
1136
1137 memset(data + len, 0, size - esize - len);
1138 }
1139
1140 perf_trace_buf_submit(entry, size, rctx, call->event.type, 1, regs,
1141 head, NULL);
1142 out:
1143 preempt_enable();
1144}
1145
1146/* uprobe profile handler */
1147static int uprobe_perf_func(struct trace_uprobe *tu, struct pt_regs *regs,
1148 struct uprobe_cpu_buffer *ucb, int dsize)
1149{
1150 if (!uprobe_perf_filter(&tu->consumer, 0, current->mm))
1151 return UPROBE_HANDLER_REMOVE;
1152
1153 if (!is_ret_probe(tu))
1154 __uprobe_perf_func(tu, 0, regs, ucb, dsize);
1155 return 0;
1156}
1157
1158static void uretprobe_perf_func(struct trace_uprobe *tu, unsigned long func,
1159 struct pt_regs *regs,
1160 struct uprobe_cpu_buffer *ucb, int dsize)
1161{
1162 __uprobe_perf_func(tu, func, regs, ucb, dsize);
1163}
1164#endif /* CONFIG_PERF_EVENTS */
1165
1166static int
1167trace_uprobe_register(struct trace_event_call *event, enum trace_reg type,
1168 void *data)
1169{
1170 struct trace_uprobe *tu = event->data;
1171 struct trace_event_file *file = data;
1172
1173 switch (type) {
1174 case TRACE_REG_REGISTER:
1175 return probe_event_enable(tu, file, NULL);
1176
1177 case TRACE_REG_UNREGISTER:
1178 probe_event_disable(tu, file);
1179 return 0;
1180
1181#ifdef CONFIG_PERF_EVENTS
1182 case TRACE_REG_PERF_REGISTER:
1183 return probe_event_enable(tu, NULL, uprobe_perf_filter);
1184
1185 case TRACE_REG_PERF_UNREGISTER:
1186 probe_event_disable(tu, NULL);
1187 return 0;
1188
1189 case TRACE_REG_PERF_OPEN:
1190 return uprobe_perf_open(tu, data);
1191
1192 case TRACE_REG_PERF_CLOSE:
1193 return uprobe_perf_close(tu, data);
1194
1195#endif
1196 default:
1197 return 0;
1198 }
1199 return 0;
1200}
1201
1202static int uprobe_dispatcher(struct uprobe_consumer *con, struct pt_regs *regs)
1203{
1204 struct trace_uprobe *tu;
1205 struct uprobe_dispatch_data udd;
1206 struct uprobe_cpu_buffer *ucb;
1207 int dsize, esize;
1208 int ret = 0;
1209
1210
1211 tu = container_of(con, struct trace_uprobe, consumer);
1212 tu->nhit++;
1213
1214 udd.tu = tu;
1215 udd.bp_addr = instruction_pointer(regs);
1216
1217 current->utask->vaddr = (unsigned long) &udd;
1218
1219 if (WARN_ON_ONCE(!uprobe_cpu_buffer))
1220 return 0;
1221
1222 dsize = __get_data_size(&tu->tp, regs);
1223 esize = SIZEOF_TRACE_ENTRY(is_ret_probe(tu));
1224
1225 ucb = uprobe_buffer_get();
1226 store_trace_args(esize, &tu->tp, regs, ucb->buf, dsize);
1227
1228 if (tu->tp.flags & TP_FLAG_TRACE)
1229 ret |= uprobe_trace_func(tu, regs, ucb, dsize);
1230
1231#ifdef CONFIG_PERF_EVENTS
1232 if (tu->tp.flags & TP_FLAG_PROFILE)
1233 ret |= uprobe_perf_func(tu, regs, ucb, dsize);
1234#endif
1235 uprobe_buffer_put(ucb);
1236 return ret;
1237}
1238
1239static int uretprobe_dispatcher(struct uprobe_consumer *con,
1240 unsigned long func, struct pt_regs *regs)
1241{
1242 struct trace_uprobe *tu;
1243 struct uprobe_dispatch_data udd;
1244 struct uprobe_cpu_buffer *ucb;
1245 int dsize, esize;
1246
1247 tu = container_of(con, struct trace_uprobe, consumer);
1248
1249 udd.tu = tu;
1250 udd.bp_addr = func;
1251
1252 current->utask->vaddr = (unsigned long) &udd;
1253
1254 if (WARN_ON_ONCE(!uprobe_cpu_buffer))
1255 return 0;
1256
1257 dsize = __get_data_size(&tu->tp, regs);
1258 esize = SIZEOF_TRACE_ENTRY(is_ret_probe(tu));
1259
1260 ucb = uprobe_buffer_get();
1261 store_trace_args(esize, &tu->tp, regs, ucb->buf, dsize);
1262
1263 if (tu->tp.flags & TP_FLAG_TRACE)
1264 uretprobe_trace_func(tu, func, regs, ucb, dsize);
1265
1266#ifdef CONFIG_PERF_EVENTS
1267 if (tu->tp.flags & TP_FLAG_PROFILE)
1268 uretprobe_perf_func(tu, func, regs, ucb, dsize);
1269#endif
1270 uprobe_buffer_put(ucb);
1271 return 0;
1272}
1273
1274static struct trace_event_functions uprobe_funcs = {
1275 .trace = print_uprobe_event
1276};
1277
1278static inline void init_trace_event_call(struct trace_uprobe *tu,
1279 struct trace_event_call *call)
1280{
1281 INIT_LIST_HEAD(&call->class->fields);
1282 call->event.funcs = &uprobe_funcs;
1283 call->class->define_fields = uprobe_event_define_fields;
1284
1285 call->flags = TRACE_EVENT_FL_UPROBE;
1286 call->class->reg = trace_uprobe_register;
1287 call->data = tu;
1288}
1289
1290static int register_uprobe_event(struct trace_uprobe *tu)
1291{
1292 struct trace_event_call *call = &tu->tp.call;
1293 int ret = 0;
1294
1295 init_trace_event_call(tu, call);
1296
1297 if (set_print_fmt(&tu->tp, is_ret_probe(tu)) < 0)
1298 return -ENOMEM;
1299
1300 ret = register_trace_event(&call->event);
1301 if (!ret) {
1302 kfree(call->print_fmt);
1303 return -ENODEV;
1304 }
1305
1306 ret = trace_add_event_call(call);
1307
1308 if (ret) {
1309 pr_info("Failed to register uprobe event: %s\n",
1310 trace_event_name(call));
1311 kfree(call->print_fmt);
1312 unregister_trace_event(&call->event);
1313 }
1314
1315 return ret;
1316}
1317
1318static int unregister_uprobe_event(struct trace_uprobe *tu)
1319{
1320 int ret;
1321
1322 /* tu->event is unregistered in trace_remove_event_call() */
1323 ret = trace_remove_event_call(&tu->tp.call);
1324 if (ret)
1325 return ret;
1326 kfree(tu->tp.call.print_fmt);
1327 tu->tp.call.print_fmt = NULL;
1328 return 0;
1329}
1330
1331#ifdef CONFIG_PERF_EVENTS
1332struct trace_event_call *
1333create_local_trace_uprobe(char *name, unsigned long offs, bool is_return)
1334{
1335 struct trace_uprobe *tu;
1336 struct path path;
1337 int ret;
1338
1339 ret = kern_path(name, LOOKUP_FOLLOW, &path);
1340 if (ret)
1341 return ERR_PTR(ret);
1342
1343 if (!d_is_reg(path.dentry)) {
1344 path_put(&path);
1345 return ERR_PTR(-EINVAL);
1346 }
1347
1348 /*
1349 * local trace_kprobes are not added to probe_list, so they are never
1350 * searched in find_trace_kprobe(). Therefore, there is no concern of
1351 * duplicated name "DUMMY_EVENT" here.
1352 */
1353 tu = alloc_trace_uprobe(UPROBE_EVENT_SYSTEM, "DUMMY_EVENT", 0,
1354 is_return);
1355
1356 if (IS_ERR(tu)) {
1357 pr_info("Failed to allocate trace_uprobe.(%d)\n",
1358 (int)PTR_ERR(tu));
1359 path_put(&path);
1360 return ERR_CAST(tu);
1361 }
1362
1363 tu->offset = offs;
1364 tu->path = path;
1365 tu->filename = kstrdup(name, GFP_KERNEL);
1366 init_trace_event_call(tu, &tu->tp.call);
1367
1368 if (set_print_fmt(&tu->tp, is_ret_probe(tu)) < 0) {
1369 ret = -ENOMEM;
1370 goto error;
1371 }
1372
1373 return &tu->tp.call;
1374error:
1375 free_trace_uprobe(tu);
1376 return ERR_PTR(ret);
1377}
1378
1379void destroy_local_trace_uprobe(struct trace_event_call *event_call)
1380{
1381 struct trace_uprobe *tu;
1382
1383 tu = container_of(event_call, struct trace_uprobe, tp.call);
1384
1385 kfree(tu->tp.call.print_fmt);
1386 tu->tp.call.print_fmt = NULL;
1387
1388 free_trace_uprobe(tu);
1389}
1390#endif /* CONFIG_PERF_EVENTS */
1391
1392/* Make a trace interface for controling probe points */
1393static __init int init_uprobe_trace(void)
1394{
1395 struct dentry *d_tracer;
1396
1397 d_tracer = tracing_init_dentry();
1398 if (IS_ERR(d_tracer))
1399 return 0;
1400
1401 trace_create_file("uprobe_events", 0644, d_tracer,
1402 NULL, &uprobe_events_ops);
1403 /* Profile interface */
1404 trace_create_file("uprobe_profile", 0444, d_tracer,
1405 NULL, &uprobe_profile_ops);
1406 return 0;
1407}
1408
1409fs_initcall(init_uprobe_trace);