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ARM: mvebu: Add support for the network controller in Armada 375 SoC
[deliverable/linux.git] / kernel / trace / trace_uprobe.c
1 /*
2 * uprobes-based tracing events
3 *
4 * This program is free software; you can redistribute it and/or modify
5 * it under the terms of the GNU General Public License version 2 as
6 * published by the Free Software Foundation.
7 *
8 * This program is distributed in the hope that it will be useful,
9 * but WITHOUT ANY WARRANTY; without even the implied warranty of
10 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
11 * GNU General Public License for more details.
12 *
13 * You should have received a copy of the GNU General Public License
14 * along with this program; if not, write to the Free Software
15 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
16 *
17 * Copyright (C) IBM Corporation, 2010-2012
18 * Author: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
19 */
20
21 #include <linux/module.h>
22 #include <linux/uaccess.h>
23 #include <linux/uprobes.h>
24 #include <linux/namei.h>
25 #include <linux/string.h>
26
27 #include "trace_probe.h"
28
29 #define UPROBE_EVENT_SYSTEM "uprobes"
30
31 struct uprobe_trace_entry_head {
32 struct trace_entry ent;
33 unsigned long vaddr[];
34 };
35
36 #define SIZEOF_TRACE_ENTRY(is_return) \
37 (sizeof(struct uprobe_trace_entry_head) + \
38 sizeof(unsigned long) * (is_return ? 2 : 1))
39
40 #define DATAOF_TRACE_ENTRY(entry, is_return) \
41 ((void*)(entry) + SIZEOF_TRACE_ENTRY(is_return))
42
43 struct trace_uprobe_filter {
44 rwlock_t rwlock;
45 int nr_systemwide;
46 struct list_head perf_events;
47 };
48
49 /*
50 * uprobe event core functions
51 */
52 struct trace_uprobe {
53 struct list_head list;
54 struct trace_uprobe_filter filter;
55 struct uprobe_consumer consumer;
56 struct inode *inode;
57 char *filename;
58 unsigned long offset;
59 unsigned long nhit;
60 struct trace_probe tp;
61 };
62
63 #define SIZEOF_TRACE_UPROBE(n) \
64 (offsetof(struct trace_uprobe, tp.args) + \
65 (sizeof(struct probe_arg) * (n)))
66
67 static int register_uprobe_event(struct trace_uprobe *tu);
68 static int unregister_uprobe_event(struct trace_uprobe *tu);
69
70 static DEFINE_MUTEX(uprobe_lock);
71 static LIST_HEAD(uprobe_list);
72
73 struct uprobe_dispatch_data {
74 struct trace_uprobe *tu;
75 unsigned long bp_addr;
76 };
77
78 static int uprobe_dispatcher(struct uprobe_consumer *con, struct pt_regs *regs);
79 static int uretprobe_dispatcher(struct uprobe_consumer *con,
80 unsigned long func, struct pt_regs *regs);
81
82 #ifdef CONFIG_STACK_GROWSUP
83 static unsigned long adjust_stack_addr(unsigned long addr, unsigned int n)
84 {
85 return addr - (n * sizeof(long));
86 }
87 #else
88 static unsigned long adjust_stack_addr(unsigned long addr, unsigned int n)
89 {
90 return addr + (n * sizeof(long));
91 }
92 #endif
93
94 static unsigned long get_user_stack_nth(struct pt_regs *regs, unsigned int n)
95 {
96 unsigned long ret;
97 unsigned long addr = user_stack_pointer(regs);
98
99 addr = adjust_stack_addr(addr, n);
100
101 if (copy_from_user(&ret, (void __force __user *) addr, sizeof(ret)))
102 return 0;
103
104 return ret;
105 }
106
107 /*
108 * Uprobes-specific fetch functions
109 */
110 #define DEFINE_FETCH_stack(type) \
111 static void FETCH_FUNC_NAME(stack, type)(struct pt_regs *regs, \
112 void *offset, void *dest) \
113 { \
114 *(type *)dest = (type)get_user_stack_nth(regs, \
115 ((unsigned long)offset)); \
116 }
117 DEFINE_BASIC_FETCH_FUNCS(stack)
118 /* No string on the stack entry */
119 #define fetch_stack_string NULL
120 #define fetch_stack_string_size NULL
121
122 #define DEFINE_FETCH_memory(type) \
123 static void FETCH_FUNC_NAME(memory, type)(struct pt_regs *regs, \
124 void *addr, void *dest) \
125 { \
126 type retval; \
127 void __user *vaddr = (void __force __user *) addr; \
128 \
129 if (copy_from_user(&retval, vaddr, sizeof(type))) \
130 *(type *)dest = 0; \
131 else \
132 *(type *) dest = retval; \
133 }
134 DEFINE_BASIC_FETCH_FUNCS(memory)
135 /*
136 * Fetch a null-terminated string. Caller MUST set *(u32 *)dest with max
137 * length and relative data location.
138 */
139 static void FETCH_FUNC_NAME(memory, string)(struct pt_regs *regs,
140 void *addr, void *dest)
141 {
142 long ret;
143 u32 rloc = *(u32 *)dest;
144 int maxlen = get_rloc_len(rloc);
145 u8 *dst = get_rloc_data(dest);
146 void __user *src = (void __force __user *) addr;
147
148 if (!maxlen)
149 return;
150
151 ret = strncpy_from_user(dst, src, maxlen);
152
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 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 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 int cpu;
736
737 BUG_ON(!mutex_is_locked(&event_mutex));
738
739 if (--uprobe_buffer_refcnt == 0) {
740 for_each_possible_cpu(cpu)
741 free_page((unsigned long)per_cpu_ptr(uprobe_cpu_buffer,
742 cpu)->buf);
743
744 free_percpu(uprobe_cpu_buffer);
745 uprobe_cpu_buffer = NULL;
746 }
747 }
748
749 static struct uprobe_cpu_buffer *uprobe_buffer_get(void)
750 {
751 struct uprobe_cpu_buffer *ucb;
752 int cpu;
753
754 cpu = raw_smp_processor_id();
755 ucb = per_cpu_ptr(uprobe_cpu_buffer, cpu);
756
757 /*
758 * Use per-cpu buffers for fastest access, but we might migrate
759 * so the mutex makes sure we have sole access to it.
760 */
761 mutex_lock(&ucb->mutex);
762
763 return ucb;
764 }
765
766 static void uprobe_buffer_put(struct uprobe_cpu_buffer *ucb)
767 {
768 mutex_unlock(&ucb->mutex);
769 }
770
771 static void __uprobe_trace_func(struct trace_uprobe *tu,
772 unsigned long func, struct pt_regs *regs,
773 struct uprobe_cpu_buffer *ucb, int dsize,
774 struct ftrace_event_file *ftrace_file)
775 {
776 struct uprobe_trace_entry_head *entry;
777 struct ring_buffer_event *event;
778 struct ring_buffer *buffer;
779 void *data;
780 int size, esize;
781 struct ftrace_event_call *call = &tu->tp.call;
782
783 WARN_ON(call != ftrace_file->event_call);
784
785 if (WARN_ON_ONCE(tu->tp.size + dsize > PAGE_SIZE))
786 return;
787
788 if (ftrace_trigger_soft_disabled(ftrace_file))
789 return;
790
791 esize = SIZEOF_TRACE_ENTRY(is_ret_probe(tu));
792 size = esize + tu->tp.size + dsize;
793 event = trace_event_buffer_lock_reserve(&buffer, ftrace_file,
794 call->event.type, size, 0, 0);
795 if (!event)
796 return;
797
798 entry = ring_buffer_event_data(event);
799 if (is_ret_probe(tu)) {
800 entry->vaddr[0] = func;
801 entry->vaddr[1] = instruction_pointer(regs);
802 data = DATAOF_TRACE_ENTRY(entry, true);
803 } else {
804 entry->vaddr[0] = instruction_pointer(regs);
805 data = DATAOF_TRACE_ENTRY(entry, false);
806 }
807
808 memcpy(data, ucb->buf, tu->tp.size + dsize);
809
810 event_trigger_unlock_commit(ftrace_file, buffer, event, entry, 0, 0);
811 }
812
813 /* uprobe handler */
814 static int uprobe_trace_func(struct trace_uprobe *tu, struct pt_regs *regs,
815 struct uprobe_cpu_buffer *ucb, int dsize)
816 {
817 struct event_file_link *link;
818
819 if (is_ret_probe(tu))
820 return 0;
821
822 rcu_read_lock();
823 list_for_each_entry_rcu(link, &tu->tp.files, list)
824 __uprobe_trace_func(tu, 0, regs, ucb, dsize, link->file);
825 rcu_read_unlock();
826
827 return 0;
828 }
829
830 static void uretprobe_trace_func(struct trace_uprobe *tu, unsigned long func,
831 struct pt_regs *regs,
832 struct uprobe_cpu_buffer *ucb, int dsize)
833 {
834 struct event_file_link *link;
835
836 rcu_read_lock();
837 list_for_each_entry_rcu(link, &tu->tp.files, list)
838 __uprobe_trace_func(tu, func, regs, ucb, dsize, link->file);
839 rcu_read_unlock();
840 }
841
842 /* Event entry printers */
843 static enum print_line_t
844 print_uprobe_event(struct trace_iterator *iter, int flags, struct trace_event *event)
845 {
846 struct uprobe_trace_entry_head *entry;
847 struct trace_seq *s = &iter->seq;
848 struct trace_uprobe *tu;
849 u8 *data;
850 int i;
851
852 entry = (struct uprobe_trace_entry_head *)iter->ent;
853 tu = container_of(event, struct trace_uprobe, tp.call.event);
854
855 if (is_ret_probe(tu)) {
856 if (!trace_seq_printf(s, "%s: (0x%lx <- 0x%lx)",
857 ftrace_event_name(&tu->tp.call),
858 entry->vaddr[1], entry->vaddr[0]))
859 goto partial;
860 data = DATAOF_TRACE_ENTRY(entry, true);
861 } else {
862 if (!trace_seq_printf(s, "%s: (0x%lx)",
863 ftrace_event_name(&tu->tp.call),
864 entry->vaddr[0]))
865 goto partial;
866 data = DATAOF_TRACE_ENTRY(entry, false);
867 }
868
869 for (i = 0; i < tu->tp.nr_args; i++) {
870 struct probe_arg *parg = &tu->tp.args[i];
871
872 if (!parg->type->print(s, parg->name, data + parg->offset, entry))
873 goto partial;
874 }
875
876 if (trace_seq_puts(s, "\n"))
877 return TRACE_TYPE_HANDLED;
878
879 partial:
880 return TRACE_TYPE_PARTIAL_LINE;
881 }
882
883 typedef bool (*filter_func_t)(struct uprobe_consumer *self,
884 enum uprobe_filter_ctx ctx,
885 struct mm_struct *mm);
886
887 static int
888 probe_event_enable(struct trace_uprobe *tu, struct ftrace_event_file *file,
889 filter_func_t filter)
890 {
891 bool enabled = trace_probe_is_enabled(&tu->tp);
892 struct event_file_link *link = NULL;
893 int ret;
894
895 if (file) {
896 link = kmalloc(sizeof(*link), GFP_KERNEL);
897 if (!link)
898 return -ENOMEM;
899
900 link->file = file;
901 list_add_tail_rcu(&link->list, &tu->tp.files);
902
903 tu->tp.flags |= TP_FLAG_TRACE;
904 } else
905 tu->tp.flags |= TP_FLAG_PROFILE;
906
907 ret = uprobe_buffer_enable();
908 if (ret < 0)
909 return ret;
910
911 WARN_ON(!uprobe_filter_is_empty(&tu->filter));
912
913 if (enabled)
914 return 0;
915
916 tu->consumer.filter = filter;
917 ret = uprobe_register(tu->inode, tu->offset, &tu->consumer);
918 if (ret) {
919 if (file) {
920 list_del(&link->list);
921 kfree(link);
922 tu->tp.flags &= ~TP_FLAG_TRACE;
923 } else
924 tu->tp.flags &= ~TP_FLAG_PROFILE;
925 }
926
927 return ret;
928 }
929
930 static void
931 probe_event_disable(struct trace_uprobe *tu, struct ftrace_event_file *file)
932 {
933 if (!trace_probe_is_enabled(&tu->tp))
934 return;
935
936 if (file) {
937 struct event_file_link *link;
938
939 link = find_event_file_link(&tu->tp, file);
940 if (!link)
941 return;
942
943 list_del_rcu(&link->list);
944 /* synchronize with u{,ret}probe_trace_func */
945 synchronize_sched();
946 kfree(link);
947
948 if (!list_empty(&tu->tp.files))
949 return;
950 }
951
952 WARN_ON(!uprobe_filter_is_empty(&tu->filter));
953
954 uprobe_unregister(tu->inode, tu->offset, &tu->consumer);
955 tu->tp.flags &= file ? ~TP_FLAG_TRACE : ~TP_FLAG_PROFILE;
956
957 uprobe_buffer_disable();
958 }
959
960 static int uprobe_event_define_fields(struct ftrace_event_call *event_call)
961 {
962 int ret, i, size;
963 struct uprobe_trace_entry_head field;
964 struct trace_uprobe *tu = event_call->data;
965
966 if (is_ret_probe(tu)) {
967 DEFINE_FIELD(unsigned long, vaddr[0], FIELD_STRING_FUNC, 0);
968 DEFINE_FIELD(unsigned long, vaddr[1], FIELD_STRING_RETIP, 0);
969 size = SIZEOF_TRACE_ENTRY(true);
970 } else {
971 DEFINE_FIELD(unsigned long, vaddr[0], FIELD_STRING_IP, 0);
972 size = SIZEOF_TRACE_ENTRY(false);
973 }
974 /* Set argument names as fields */
975 for (i = 0; i < tu->tp.nr_args; i++) {
976 struct probe_arg *parg = &tu->tp.args[i];
977
978 ret = trace_define_field(event_call, parg->type->fmttype,
979 parg->name, size + parg->offset,
980 parg->type->size, parg->type->is_signed,
981 FILTER_OTHER);
982
983 if (ret)
984 return ret;
985 }
986 return 0;
987 }
988
989 #ifdef CONFIG_PERF_EVENTS
990 static bool
991 __uprobe_perf_filter(struct trace_uprobe_filter *filter, struct mm_struct *mm)
992 {
993 struct perf_event *event;
994
995 if (filter->nr_systemwide)
996 return true;
997
998 list_for_each_entry(event, &filter->perf_events, hw.tp_list) {
999 if (event->hw.tp_target->mm == mm)
1000 return true;
1001 }
1002
1003 return false;
1004 }
1005
1006 static inline bool
1007 uprobe_filter_event(struct trace_uprobe *tu, struct perf_event *event)
1008 {
1009 return __uprobe_perf_filter(&tu->filter, event->hw.tp_target->mm);
1010 }
1011
1012 static int uprobe_perf_close(struct trace_uprobe *tu, struct perf_event *event)
1013 {
1014 bool done;
1015
1016 write_lock(&tu->filter.rwlock);
1017 if (event->hw.tp_target) {
1018 list_del(&event->hw.tp_list);
1019 done = tu->filter.nr_systemwide ||
1020 (event->hw.tp_target->flags & PF_EXITING) ||
1021 uprobe_filter_event(tu, event);
1022 } else {
1023 tu->filter.nr_systemwide--;
1024 done = tu->filter.nr_systemwide;
1025 }
1026 write_unlock(&tu->filter.rwlock);
1027
1028 if (!done)
1029 return uprobe_apply(tu->inode, tu->offset, &tu->consumer, false);
1030
1031 return 0;
1032 }
1033
1034 static int uprobe_perf_open(struct trace_uprobe *tu, struct perf_event *event)
1035 {
1036 bool done;
1037 int err;
1038
1039 write_lock(&tu->filter.rwlock);
1040 if (event->hw.tp_target) {
1041 /*
1042 * event->parent != NULL means copy_process(), we can avoid
1043 * uprobe_apply(). current->mm must be probed and we can rely
1044 * on dup_mmap() which preserves the already installed bp's.
1045 *
1046 * attr.enable_on_exec means that exec/mmap will install the
1047 * breakpoints we need.
1048 */
1049 done = tu->filter.nr_systemwide ||
1050 event->parent || event->attr.enable_on_exec ||
1051 uprobe_filter_event(tu, event);
1052 list_add(&event->hw.tp_list, &tu->filter.perf_events);
1053 } else {
1054 done = tu->filter.nr_systemwide;
1055 tu->filter.nr_systemwide++;
1056 }
1057 write_unlock(&tu->filter.rwlock);
1058
1059 err = 0;
1060 if (!done) {
1061 err = uprobe_apply(tu->inode, tu->offset, &tu->consumer, true);
1062 if (err)
1063 uprobe_perf_close(tu, event);
1064 }
1065 return err;
1066 }
1067
1068 static bool uprobe_perf_filter(struct uprobe_consumer *uc,
1069 enum uprobe_filter_ctx ctx, struct mm_struct *mm)
1070 {
1071 struct trace_uprobe *tu;
1072 int ret;
1073
1074 tu = container_of(uc, struct trace_uprobe, consumer);
1075 read_lock(&tu->filter.rwlock);
1076 ret = __uprobe_perf_filter(&tu->filter, mm);
1077 read_unlock(&tu->filter.rwlock);
1078
1079 return ret;
1080 }
1081
1082 static void __uprobe_perf_func(struct trace_uprobe *tu,
1083 unsigned long func, struct pt_regs *regs,
1084 struct uprobe_cpu_buffer *ucb, int dsize)
1085 {
1086 struct ftrace_event_call *call = &tu->tp.call;
1087 struct uprobe_trace_entry_head *entry;
1088 struct hlist_head *head;
1089 void *data;
1090 int size, esize;
1091 int rctx;
1092
1093 esize = SIZEOF_TRACE_ENTRY(is_ret_probe(tu));
1094
1095 size = esize + tu->tp.size + dsize;
1096 size = ALIGN(size + sizeof(u32), sizeof(u64)) - sizeof(u32);
1097 if (WARN_ONCE(size > PERF_MAX_TRACE_SIZE, "profile buffer not large enough"))
1098 return;
1099
1100 preempt_disable();
1101 head = this_cpu_ptr(call->perf_events);
1102 if (hlist_empty(head))
1103 goto out;
1104
1105 entry = perf_trace_buf_prepare(size, call->event.type, regs, &rctx);
1106 if (!entry)
1107 goto out;
1108
1109 if (is_ret_probe(tu)) {
1110 entry->vaddr[0] = func;
1111 entry->vaddr[1] = instruction_pointer(regs);
1112 data = DATAOF_TRACE_ENTRY(entry, true);
1113 } else {
1114 entry->vaddr[0] = instruction_pointer(regs);
1115 data = DATAOF_TRACE_ENTRY(entry, false);
1116 }
1117
1118 memcpy(data, ucb->buf, tu->tp.size + dsize);
1119
1120 if (size - esize > tu->tp.size + dsize) {
1121 int len = tu->tp.size + dsize;
1122
1123 memset(data + len, 0, size - esize - len);
1124 }
1125
1126 perf_trace_buf_submit(entry, size, rctx, 0, 1, regs, head, NULL);
1127 out:
1128 preempt_enable();
1129 }
1130
1131 /* uprobe profile handler */
1132 static int uprobe_perf_func(struct trace_uprobe *tu, struct pt_regs *regs,
1133 struct uprobe_cpu_buffer *ucb, int dsize)
1134 {
1135 if (!uprobe_perf_filter(&tu->consumer, 0, current->mm))
1136 return UPROBE_HANDLER_REMOVE;
1137
1138 if (!is_ret_probe(tu))
1139 __uprobe_perf_func(tu, 0, regs, ucb, dsize);
1140 return 0;
1141 }
1142
1143 static void uretprobe_perf_func(struct trace_uprobe *tu, unsigned long func,
1144 struct pt_regs *regs,
1145 struct uprobe_cpu_buffer *ucb, int dsize)
1146 {
1147 __uprobe_perf_func(tu, func, regs, ucb, dsize);
1148 }
1149 #endif /* CONFIG_PERF_EVENTS */
1150
1151 static int
1152 trace_uprobe_register(struct ftrace_event_call *event, enum trace_reg type,
1153 void *data)
1154 {
1155 struct trace_uprobe *tu = event->data;
1156 struct ftrace_event_file *file = data;
1157
1158 switch (type) {
1159 case TRACE_REG_REGISTER:
1160 return probe_event_enable(tu, file, NULL);
1161
1162 case TRACE_REG_UNREGISTER:
1163 probe_event_disable(tu, file);
1164 return 0;
1165
1166 #ifdef CONFIG_PERF_EVENTS
1167 case TRACE_REG_PERF_REGISTER:
1168 return probe_event_enable(tu, NULL, uprobe_perf_filter);
1169
1170 case TRACE_REG_PERF_UNREGISTER:
1171 probe_event_disable(tu, NULL);
1172 return 0;
1173
1174 case TRACE_REG_PERF_OPEN:
1175 return uprobe_perf_open(tu, data);
1176
1177 case TRACE_REG_PERF_CLOSE:
1178 return uprobe_perf_close(tu, data);
1179
1180 #endif
1181 default:
1182 return 0;
1183 }
1184 return 0;
1185 }
1186
1187 static int uprobe_dispatcher(struct uprobe_consumer *con, struct pt_regs *regs)
1188 {
1189 struct trace_uprobe *tu;
1190 struct uprobe_dispatch_data udd;
1191 struct uprobe_cpu_buffer *ucb;
1192 int dsize, esize;
1193 int ret = 0;
1194
1195
1196 tu = container_of(con, struct trace_uprobe, consumer);
1197 tu->nhit++;
1198
1199 udd.tu = tu;
1200 udd.bp_addr = instruction_pointer(regs);
1201
1202 current->utask->vaddr = (unsigned long) &udd;
1203
1204 #ifdef CONFIG_PERF_EVENTS
1205 if ((tu->tp.flags & TP_FLAG_TRACE) == 0 &&
1206 !uprobe_perf_filter(&tu->consumer, 0, current->mm))
1207 return UPROBE_HANDLER_REMOVE;
1208 #endif
1209
1210 if (WARN_ON_ONCE(!uprobe_cpu_buffer))
1211 return 0;
1212
1213 dsize = __get_data_size(&tu->tp, regs);
1214 esize = SIZEOF_TRACE_ENTRY(is_ret_probe(tu));
1215
1216 ucb = uprobe_buffer_get();
1217 store_trace_args(esize, &tu->tp, regs, ucb->buf, dsize);
1218
1219 if (tu->tp.flags & TP_FLAG_TRACE)
1220 ret |= uprobe_trace_func(tu, regs, ucb, dsize);
1221
1222 #ifdef CONFIG_PERF_EVENTS
1223 if (tu->tp.flags & TP_FLAG_PROFILE)
1224 ret |= uprobe_perf_func(tu, regs, ucb, dsize);
1225 #endif
1226 uprobe_buffer_put(ucb);
1227 return ret;
1228 }
1229
1230 static int uretprobe_dispatcher(struct uprobe_consumer *con,
1231 unsigned long func, struct pt_regs *regs)
1232 {
1233 struct trace_uprobe *tu;
1234 struct uprobe_dispatch_data udd;
1235 struct uprobe_cpu_buffer *ucb;
1236 int dsize, esize;
1237
1238 tu = container_of(con, struct trace_uprobe, consumer);
1239
1240 udd.tu = tu;
1241 udd.bp_addr = func;
1242
1243 current->utask->vaddr = (unsigned long) &udd;
1244
1245 if (WARN_ON_ONCE(!uprobe_cpu_buffer))
1246 return 0;
1247
1248 dsize = __get_data_size(&tu->tp, regs);
1249 esize = SIZEOF_TRACE_ENTRY(is_ret_probe(tu));
1250
1251 ucb = uprobe_buffer_get();
1252 store_trace_args(esize, &tu->tp, regs, ucb->buf, dsize);
1253
1254 if (tu->tp.flags & TP_FLAG_TRACE)
1255 uretprobe_trace_func(tu, func, regs, ucb, dsize);
1256
1257 #ifdef CONFIG_PERF_EVENTS
1258 if (tu->tp.flags & TP_FLAG_PROFILE)
1259 uretprobe_perf_func(tu, func, regs, ucb, dsize);
1260 #endif
1261 uprobe_buffer_put(ucb);
1262 return 0;
1263 }
1264
1265 static struct trace_event_functions uprobe_funcs = {
1266 .trace = print_uprobe_event
1267 };
1268
1269 static int register_uprobe_event(struct trace_uprobe *tu)
1270 {
1271 struct ftrace_event_call *call = &tu->tp.call;
1272 int ret;
1273
1274 /* Initialize ftrace_event_call */
1275 INIT_LIST_HEAD(&call->class->fields);
1276 call->event.funcs = &uprobe_funcs;
1277 call->class->define_fields = uprobe_event_define_fields;
1278
1279 if (set_print_fmt(&tu->tp, is_ret_probe(tu)) < 0)
1280 return -ENOMEM;
1281
1282 ret = register_ftrace_event(&call->event);
1283 if (!ret) {
1284 kfree(call->print_fmt);
1285 return -ENODEV;
1286 }
1287 call->flags = 0;
1288 call->class->reg = trace_uprobe_register;
1289 call->data = tu;
1290 ret = trace_add_event_call(call);
1291
1292 if (ret) {
1293 pr_info("Failed to register uprobe event: %s\n",
1294 ftrace_event_name(call));
1295 kfree(call->print_fmt);
1296 unregister_ftrace_event(&call->event);
1297 }
1298
1299 return ret;
1300 }
1301
1302 static int unregister_uprobe_event(struct trace_uprobe *tu)
1303 {
1304 int ret;
1305
1306 /* tu->event is unregistered in trace_remove_event_call() */
1307 ret = trace_remove_event_call(&tu->tp.call);
1308 if (ret)
1309 return ret;
1310 kfree(tu->tp.call.print_fmt);
1311 tu->tp.call.print_fmt = NULL;
1312 return 0;
1313 }
1314
1315 /* Make a trace interface for controling probe points */
1316 static __init int init_uprobe_trace(void)
1317 {
1318 struct dentry *d_tracer;
1319
1320 d_tracer = tracing_init_dentry();
1321 if (!d_tracer)
1322 return 0;
1323
1324 trace_create_file("uprobe_events", 0644, d_tracer,
1325 NULL, &uprobe_events_ops);
1326 /* Profile interface */
1327 trace_create_file("uprobe_profile", 0444, d_tracer,
1328 NULL, &uprobe_profile_ops);
1329 return 0;
1330 }
1331
1332 fs_initcall(init_uprobe_trace);
Linux kernel - Deliverables
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