tracing/kprobes: Increment probe hit-count even if it is used by perf
[linux-3.10.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 trace_uprobe_filter {
32         rwlock_t                rwlock;
33         int                     nr_systemwide;
34         struct list_head        perf_events;
35 };
36
37 /*
38  * uprobe event core functions
39  */
40 struct trace_uprobe {
41         struct list_head                list;
42         struct ftrace_event_class       class;
43         struct ftrace_event_call        call;
44         struct trace_uprobe_filter      filter;
45         struct uprobe_consumer          consumer;
46         struct inode                    *inode;
47         char                            *filename;
48         unsigned long                   offset;
49         unsigned long                   nhit;
50         unsigned int                    flags;  /* For TP_FLAG_* */
51         ssize_t                         size;   /* trace entry size */
52         unsigned int                    nr_args;
53         struct probe_arg                args[];
54 };
55
56 #define SIZEOF_TRACE_UPROBE(n)                  \
57         (offsetof(struct trace_uprobe, args) +  \
58         (sizeof(struct probe_arg) * (n)))
59
60 static int register_uprobe_event(struct trace_uprobe *tu);
61 static void unregister_uprobe_event(struct trace_uprobe *tu);
62
63 static DEFINE_MUTEX(uprobe_lock);
64 static LIST_HEAD(uprobe_list);
65
66 static int uprobe_dispatcher(struct uprobe_consumer *con, struct pt_regs *regs);
67
68 static inline void init_trace_uprobe_filter(struct trace_uprobe_filter *filter)
69 {
70         rwlock_init(&filter->rwlock);
71         filter->nr_systemwide = 0;
72         INIT_LIST_HEAD(&filter->perf_events);
73 }
74
75 static inline bool uprobe_filter_is_empty(struct trace_uprobe_filter *filter)
76 {
77         return !filter->nr_systemwide && list_empty(&filter->perf_events);
78 }
79
80 /*
81  * Allocate new trace_uprobe and initialize it (including uprobes).
82  */
83 static struct trace_uprobe *
84 alloc_trace_uprobe(const char *group, const char *event, int nargs)
85 {
86         struct trace_uprobe *tu;
87
88         if (!event || !is_good_name(event))
89                 return ERR_PTR(-EINVAL);
90
91         if (!group || !is_good_name(group))
92                 return ERR_PTR(-EINVAL);
93
94         tu = kzalloc(SIZEOF_TRACE_UPROBE(nargs), GFP_KERNEL);
95         if (!tu)
96                 return ERR_PTR(-ENOMEM);
97
98         tu->call.class = &tu->class;
99         tu->call.name = kstrdup(event, GFP_KERNEL);
100         if (!tu->call.name)
101                 goto error;
102
103         tu->class.system = kstrdup(group, GFP_KERNEL);
104         if (!tu->class.system)
105                 goto error;
106
107         INIT_LIST_HEAD(&tu->list);
108         tu->consumer.handler = uprobe_dispatcher;
109         init_trace_uprobe_filter(&tu->filter);
110         return tu;
111
112 error:
113         kfree(tu->call.name);
114         kfree(tu);
115
116         return ERR_PTR(-ENOMEM);
117 }
118
119 static void free_trace_uprobe(struct trace_uprobe *tu)
120 {
121         int i;
122
123         for (i = 0; i < tu->nr_args; i++)
124                 traceprobe_free_probe_arg(&tu->args[i]);
125
126         iput(tu->inode);
127         kfree(tu->call.class->system);
128         kfree(tu->call.name);
129         kfree(tu->filename);
130         kfree(tu);
131 }
132
133 static struct trace_uprobe *find_probe_event(const char *event, const char *group)
134 {
135         struct trace_uprobe *tu;
136
137         list_for_each_entry(tu, &uprobe_list, list)
138                 if (strcmp(tu->call.name, event) == 0 &&
139                     strcmp(tu->call.class->system, group) == 0)
140                         return tu;
141
142         return NULL;
143 }
144
145 /* Unregister a trace_uprobe and probe_event: call with locking uprobe_lock */
146 static void unregister_trace_uprobe(struct trace_uprobe *tu)
147 {
148         list_del(&tu->list);
149         unregister_uprobe_event(tu);
150         free_trace_uprobe(tu);
151 }
152
153 /* Register a trace_uprobe and probe_event */
154 static int register_trace_uprobe(struct trace_uprobe *tu)
155 {
156         struct trace_uprobe *old_tp;
157         int ret;
158
159         mutex_lock(&uprobe_lock);
160
161         /* register as an event */
162         old_tp = find_probe_event(tu->call.name, tu->call.class->system);
163         if (old_tp)
164                 /* delete old event */
165                 unregister_trace_uprobe(old_tp);
166
167         ret = register_uprobe_event(tu);
168         if (ret) {
169                 pr_warning("Failed to register probe event(%d)\n", ret);
170                 goto end;
171         }
172
173         list_add_tail(&tu->list, &uprobe_list);
174
175 end:
176         mutex_unlock(&uprobe_lock);
177
178         return ret;
179 }
180
181 /*
182  * Argument syntax:
183  *  - Add uprobe: p[:[GRP/]EVENT] PATH:SYMBOL[+offs] [FETCHARGS]
184  *
185  *  - Remove uprobe: -:[GRP/]EVENT
186  */
187 static int create_trace_uprobe(int argc, char **argv)
188 {
189         struct trace_uprobe *tu;
190         struct inode *inode;
191         char *arg, *event, *group, *filename;
192         char buf[MAX_EVENT_NAME_LEN];
193         struct path path;
194         unsigned long offset;
195         bool is_delete;
196         int i, ret;
197
198         inode = NULL;
199         ret = 0;
200         is_delete = false;
201         event = NULL;
202         group = NULL;
203
204         /* argc must be >= 1 */
205         if (argv[0][0] == '-')
206                 is_delete = true;
207         else if (argv[0][0] != 'p') {
208                 pr_info("Probe definition must be started with 'p' or '-'.\n");
209                 return -EINVAL;
210         }
211
212         if (argv[0][1] == ':') {
213                 event = &argv[0][2];
214                 arg = strchr(event, '/');
215
216                 if (arg) {
217                         group = event;
218                         event = arg + 1;
219                         event[-1] = '\0';
220
221                         if (strlen(group) == 0) {
222                                 pr_info("Group name is not specified\n");
223                                 return -EINVAL;
224                         }
225                 }
226                 if (strlen(event) == 0) {
227                         pr_info("Event name is not specified\n");
228                         return -EINVAL;
229                 }
230         }
231         if (!group)
232                 group = UPROBE_EVENT_SYSTEM;
233
234         if (is_delete) {
235                 if (!event) {
236                         pr_info("Delete command needs an event name.\n");
237                         return -EINVAL;
238                 }
239                 mutex_lock(&uprobe_lock);
240                 tu = find_probe_event(event, group);
241
242                 if (!tu) {
243                         mutex_unlock(&uprobe_lock);
244                         pr_info("Event %s/%s doesn't exist.\n", group, event);
245                         return -ENOENT;
246                 }
247                 /* delete an event */
248                 unregister_trace_uprobe(tu);
249                 mutex_unlock(&uprobe_lock);
250                 return 0;
251         }
252
253         if (argc < 2) {
254                 pr_info("Probe point is not specified.\n");
255                 return -EINVAL;
256         }
257         if (isdigit(argv[1][0])) {
258                 pr_info("probe point must be have a filename.\n");
259                 return -EINVAL;
260         }
261         arg = strchr(argv[1], ':');
262         if (!arg)
263                 goto fail_address_parse;
264
265         *arg++ = '\0';
266         filename = argv[1];
267         ret = kern_path(filename, LOOKUP_FOLLOW, &path);
268         if (ret)
269                 goto fail_address_parse;
270
271         inode = igrab(path.dentry->d_inode);
272         path_put(&path);
273
274         if (!inode || !S_ISREG(inode->i_mode)) {
275                 ret = -EINVAL;
276                 goto fail_address_parse;
277         }
278
279         ret = kstrtoul(arg, 0, &offset);
280         if (ret)
281                 goto fail_address_parse;
282
283         argc -= 2;
284         argv += 2;
285
286         /* setup a probe */
287         if (!event) {
288                 char *tail;
289                 char *ptr;
290
291                 tail = kstrdup(kbasename(filename), GFP_KERNEL);
292                 if (!tail) {
293                         ret = -ENOMEM;
294                         goto fail_address_parse;
295                 }
296
297                 ptr = strpbrk(tail, ".-_");
298                 if (ptr)
299                         *ptr = '\0';
300
301                 snprintf(buf, MAX_EVENT_NAME_LEN, "%c_%s_0x%lx", 'p', tail, offset);
302                 event = buf;
303                 kfree(tail);
304         }
305
306         tu = alloc_trace_uprobe(group, event, argc);
307         if (IS_ERR(tu)) {
308                 pr_info("Failed to allocate trace_uprobe.(%d)\n", (int)PTR_ERR(tu));
309                 ret = PTR_ERR(tu);
310                 goto fail_address_parse;
311         }
312         tu->offset = offset;
313         tu->inode = inode;
314         tu->filename = kstrdup(filename, GFP_KERNEL);
315
316         if (!tu->filename) {
317                 pr_info("Failed to allocate filename.\n");
318                 ret = -ENOMEM;
319                 goto error;
320         }
321
322         /* parse arguments */
323         ret = 0;
324         for (i = 0; i < argc && i < MAX_TRACE_ARGS; i++) {
325                 /* Increment count for freeing args in error case */
326                 tu->nr_args++;
327
328                 /* Parse argument name */
329                 arg = strchr(argv[i], '=');
330                 if (arg) {
331                         *arg++ = '\0';
332                         tu->args[i].name = kstrdup(argv[i], GFP_KERNEL);
333                 } else {
334                         arg = argv[i];
335                         /* If argument name is omitted, set "argN" */
336                         snprintf(buf, MAX_EVENT_NAME_LEN, "arg%d", i + 1);
337                         tu->args[i].name = kstrdup(buf, GFP_KERNEL);
338                 }
339
340                 if (!tu->args[i].name) {
341                         pr_info("Failed to allocate argument[%d] name.\n", i);
342                         ret = -ENOMEM;
343                         goto error;
344                 }
345
346                 if (!is_good_name(tu->args[i].name)) {
347                         pr_info("Invalid argument[%d] name: %s\n", i, tu->args[i].name);
348                         ret = -EINVAL;
349                         goto error;
350                 }
351
352                 if (traceprobe_conflict_field_name(tu->args[i].name, tu->args, i)) {
353                         pr_info("Argument[%d] name '%s' conflicts with "
354                                 "another field.\n", i, argv[i]);
355                         ret = -EINVAL;
356                         goto error;
357                 }
358
359                 /* Parse fetch argument */
360                 ret = traceprobe_parse_probe_arg(arg, &tu->size, &tu->args[i], false, false);
361                 if (ret) {
362                         pr_info("Parse error at argument[%d]. (%d)\n", i, ret);
363                         goto error;
364                 }
365         }
366
367         ret = register_trace_uprobe(tu);
368         if (ret)
369                 goto error;
370         return 0;
371
372 error:
373         free_trace_uprobe(tu);
374         return ret;
375
376 fail_address_parse:
377         if (inode)
378                 iput(inode);
379
380         pr_info("Failed to parse address or file.\n");
381
382         return ret;
383 }
384
385 static void cleanup_all_probes(void)
386 {
387         struct trace_uprobe *tu;
388
389         mutex_lock(&uprobe_lock);
390         while (!list_empty(&uprobe_list)) {
391                 tu = list_entry(uprobe_list.next, struct trace_uprobe, list);
392                 unregister_trace_uprobe(tu);
393         }
394         mutex_unlock(&uprobe_lock);
395 }
396
397 /* Probes listing interfaces */
398 static void *probes_seq_start(struct seq_file *m, loff_t *pos)
399 {
400         mutex_lock(&uprobe_lock);
401         return seq_list_start(&uprobe_list, *pos);
402 }
403
404 static void *probes_seq_next(struct seq_file *m, void *v, loff_t *pos)
405 {
406         return seq_list_next(v, &uprobe_list, pos);
407 }
408
409 static void probes_seq_stop(struct seq_file *m, void *v)
410 {
411         mutex_unlock(&uprobe_lock);
412 }
413
414 static int probes_seq_show(struct seq_file *m, void *v)
415 {
416         struct trace_uprobe *tu = v;
417         int i;
418
419         seq_printf(m, "p:%s/%s", tu->call.class->system, tu->call.name);
420         seq_printf(m, " %s:0x%p", tu->filename, (void *)tu->offset);
421
422         for (i = 0; i < tu->nr_args; i++)
423                 seq_printf(m, " %s=%s", tu->args[i].name, tu->args[i].comm);
424
425         seq_printf(m, "\n");
426         return 0;
427 }
428
429 static const struct seq_operations probes_seq_op = {
430         .start  = probes_seq_start,
431         .next   = probes_seq_next,
432         .stop   = probes_seq_stop,
433         .show   = probes_seq_show
434 };
435
436 static int probes_open(struct inode *inode, struct file *file)
437 {
438         if ((file->f_mode & FMODE_WRITE) && (file->f_flags & O_TRUNC))
439                 cleanup_all_probes();
440
441         return seq_open(file, &probes_seq_op);
442 }
443
444 static ssize_t probes_write(struct file *file, const char __user *buffer,
445                             size_t count, loff_t *ppos)
446 {
447         return traceprobe_probes_write(file, buffer, count, ppos, create_trace_uprobe);
448 }
449
450 static const struct file_operations uprobe_events_ops = {
451         .owner          = THIS_MODULE,
452         .open           = probes_open,
453         .read           = seq_read,
454         .llseek         = seq_lseek,
455         .release        = seq_release,
456         .write          = probes_write,
457 };
458
459 /* Probes profiling interfaces */
460 static int probes_profile_seq_show(struct seq_file *m, void *v)
461 {
462         struct trace_uprobe *tu = v;
463
464         seq_printf(m, "  %s %-44s %15lu\n", tu->filename, tu->call.name, tu->nhit);
465         return 0;
466 }
467
468 static const struct seq_operations profile_seq_op = {
469         .start  = probes_seq_start,
470         .next   = probes_seq_next,
471         .stop   = probes_seq_stop,
472         .show   = probes_profile_seq_show
473 };
474
475 static int profile_open(struct inode *inode, struct file *file)
476 {
477         return seq_open(file, &profile_seq_op);
478 }
479
480 static const struct file_operations uprobe_profile_ops = {
481         .owner          = THIS_MODULE,
482         .open           = profile_open,
483         .read           = seq_read,
484         .llseek         = seq_lseek,
485         .release        = seq_release,
486 };
487
488 /* uprobe handler */
489 static int uprobe_trace_func(struct trace_uprobe *tu, struct pt_regs *regs)
490 {
491         struct uprobe_trace_entry_head *entry;
492         struct ring_buffer_event *event;
493         struct ring_buffer *buffer;
494         u8 *data;
495         int size, i, pc;
496         unsigned long irq_flags;
497         struct ftrace_event_call *call = &tu->call;
498
499         local_save_flags(irq_flags);
500         pc = preempt_count();
501
502         size = sizeof(*entry) + tu->size;
503
504         event = trace_current_buffer_lock_reserve(&buffer, call->event.type,
505                                                   size, irq_flags, pc);
506         if (!event)
507                 return 0;
508
509         entry = ring_buffer_event_data(event);
510         entry->ip = instruction_pointer(task_pt_regs(current));
511         data = (u8 *)&entry[1];
512         for (i = 0; i < tu->nr_args; i++)
513                 call_fetch(&tu->args[i].fetch, regs, data + tu->args[i].offset);
514
515         if (!filter_current_check_discard(buffer, call, entry, event))
516                 trace_buffer_unlock_commit(buffer, event, irq_flags, pc);
517
518         return 0;
519 }
520
521 /* Event entry printers */
522 static enum print_line_t
523 print_uprobe_event(struct trace_iterator *iter, int flags, struct trace_event *event)
524 {
525         struct uprobe_trace_entry_head *field;
526         struct trace_seq *s = &iter->seq;
527         struct trace_uprobe *tu;
528         u8 *data;
529         int i;
530
531         field = (struct uprobe_trace_entry_head *)iter->ent;
532         tu = container_of(event, struct trace_uprobe, call.event);
533
534         if (!trace_seq_printf(s, "%s: (", tu->call.name))
535                 goto partial;
536
537         if (!seq_print_ip_sym(s, field->ip, flags | TRACE_ITER_SYM_OFFSET))
538                 goto partial;
539
540         if (!trace_seq_puts(s, ")"))
541                 goto partial;
542
543         data = (u8 *)&field[1];
544         for (i = 0; i < tu->nr_args; i++) {
545                 if (!tu->args[i].type->print(s, tu->args[i].name,
546                                              data + tu->args[i].offset, field))
547                         goto partial;
548         }
549
550         if (trace_seq_puts(s, "\n"))
551                 return TRACE_TYPE_HANDLED;
552
553 partial:
554         return TRACE_TYPE_PARTIAL_LINE;
555 }
556
557 static inline bool is_trace_uprobe_enabled(struct trace_uprobe *tu)
558 {
559         return tu->flags & (TP_FLAG_TRACE | TP_FLAG_PROFILE);
560 }
561
562 typedef bool (*filter_func_t)(struct uprobe_consumer *self,
563                                 enum uprobe_filter_ctx ctx,
564                                 struct mm_struct *mm);
565
566 static int
567 probe_event_enable(struct trace_uprobe *tu, int flag, filter_func_t filter)
568 {
569         int ret = 0;
570
571         if (is_trace_uprobe_enabled(tu))
572                 return -EINTR;
573
574         WARN_ON(!uprobe_filter_is_empty(&tu->filter));
575
576         tu->flags |= flag;
577         tu->consumer.filter = filter;
578         ret = uprobe_register(tu->inode, tu->offset, &tu->consumer);
579         if (ret)
580                 tu->flags &= ~flag;
581
582         return ret;
583 }
584
585 static void probe_event_disable(struct trace_uprobe *tu, int flag)
586 {
587         if (!is_trace_uprobe_enabled(tu))
588                 return;
589
590         WARN_ON(!uprobe_filter_is_empty(&tu->filter));
591
592         uprobe_unregister(tu->inode, tu->offset, &tu->consumer);
593         tu->flags &= ~flag;
594 }
595
596 static int uprobe_event_define_fields(struct ftrace_event_call *event_call)
597 {
598         int ret, i;
599         struct uprobe_trace_entry_head field;
600         struct trace_uprobe *tu = (struct trace_uprobe *)event_call->data;
601
602         DEFINE_FIELD(unsigned long, ip, FIELD_STRING_IP, 0);
603         /* Set argument names as fields */
604         for (i = 0; i < tu->nr_args; i++) {
605                 ret = trace_define_field(event_call, tu->args[i].type->fmttype,
606                                          tu->args[i].name,
607                                          sizeof(field) + tu->args[i].offset,
608                                          tu->args[i].type->size,
609                                          tu->args[i].type->is_signed,
610                                          FILTER_OTHER);
611
612                 if (ret)
613                         return ret;
614         }
615         return 0;
616 }
617
618 #define LEN_OR_ZERO             (len ? len - pos : 0)
619 static int __set_print_fmt(struct trace_uprobe *tu, char *buf, int len)
620 {
621         const char *fmt, *arg;
622         int i;
623         int pos = 0;
624
625         fmt = "(%lx)";
626         arg = "REC->" FIELD_STRING_IP;
627
628         /* When len=0, we just calculate the needed length */
629
630         pos += snprintf(buf + pos, LEN_OR_ZERO, "\"%s", fmt);
631
632         for (i = 0; i < tu->nr_args; i++) {
633                 pos += snprintf(buf + pos, LEN_OR_ZERO, " %s=%s",
634                                 tu->args[i].name, tu->args[i].type->fmt);
635         }
636
637         pos += snprintf(buf + pos, LEN_OR_ZERO, "\", %s", arg);
638
639         for (i = 0; i < tu->nr_args; i++) {
640                 pos += snprintf(buf + pos, LEN_OR_ZERO, ", REC->%s",
641                                 tu->args[i].name);
642         }
643
644         return pos;     /* return the length of print_fmt */
645 }
646 #undef LEN_OR_ZERO
647
648 static int set_print_fmt(struct trace_uprobe *tu)
649 {
650         char *print_fmt;
651         int len;
652
653         /* First: called with 0 length to calculate the needed length */
654         len = __set_print_fmt(tu, NULL, 0);
655         print_fmt = kmalloc(len + 1, GFP_KERNEL);
656         if (!print_fmt)
657                 return -ENOMEM;
658
659         /* Second: actually write the @print_fmt */
660         __set_print_fmt(tu, print_fmt, len + 1);
661         tu->call.print_fmt = print_fmt;
662
663         return 0;
664 }
665
666 #ifdef CONFIG_PERF_EVENTS
667 static bool
668 __uprobe_perf_filter(struct trace_uprobe_filter *filter, struct mm_struct *mm)
669 {
670         struct perf_event *event;
671
672         if (filter->nr_systemwide)
673                 return true;
674
675         list_for_each_entry(event, &filter->perf_events, hw.tp_list) {
676                 if (event->hw.tp_target->mm == mm)
677                         return true;
678         }
679
680         return false;
681 }
682
683 static inline bool
684 uprobe_filter_event(struct trace_uprobe *tu, struct perf_event *event)
685 {
686         return __uprobe_perf_filter(&tu->filter, event->hw.tp_target->mm);
687 }
688
689 static int uprobe_perf_open(struct trace_uprobe *tu, struct perf_event *event)
690 {
691         bool done;
692
693         write_lock(&tu->filter.rwlock);
694         if (event->hw.tp_target) {
695                 /*
696                  * event->parent != NULL means copy_process(), we can avoid
697                  * uprobe_apply(). current->mm must be probed and we can rely
698                  * on dup_mmap() which preserves the already installed bp's.
699                  *
700                  * attr.enable_on_exec means that exec/mmap will install the
701                  * breakpoints we need.
702                  */
703                 done = tu->filter.nr_systemwide ||
704                         event->parent || event->attr.enable_on_exec ||
705                         uprobe_filter_event(tu, event);
706                 list_add(&event->hw.tp_list, &tu->filter.perf_events);
707         } else {
708                 done = tu->filter.nr_systemwide;
709                 tu->filter.nr_systemwide++;
710         }
711         write_unlock(&tu->filter.rwlock);
712
713         if (!done)
714                 uprobe_apply(tu->inode, tu->offset, &tu->consumer, true);
715
716         return 0;
717 }
718
719 static int uprobe_perf_close(struct trace_uprobe *tu, struct perf_event *event)
720 {
721         bool done;
722
723         write_lock(&tu->filter.rwlock);
724         if (event->hw.tp_target) {
725                 list_del(&event->hw.tp_list);
726                 done = tu->filter.nr_systemwide ||
727                         (event->hw.tp_target->flags & PF_EXITING) ||
728                         uprobe_filter_event(tu, event);
729         } else {
730                 tu->filter.nr_systemwide--;
731                 done = tu->filter.nr_systemwide;
732         }
733         write_unlock(&tu->filter.rwlock);
734
735         if (!done)
736                 uprobe_apply(tu->inode, tu->offset, &tu->consumer, false);
737
738         return 0;
739 }
740
741 static bool uprobe_perf_filter(struct uprobe_consumer *uc,
742                                 enum uprobe_filter_ctx ctx, struct mm_struct *mm)
743 {
744         struct trace_uprobe *tu;
745         int ret;
746
747         tu = container_of(uc, struct trace_uprobe, consumer);
748         read_lock(&tu->filter.rwlock);
749         ret = __uprobe_perf_filter(&tu->filter, mm);
750         read_unlock(&tu->filter.rwlock);
751
752         return ret;
753 }
754
755 /* uprobe profile handler */
756 static int uprobe_perf_func(struct trace_uprobe *tu, struct pt_regs *regs)
757 {
758         struct ftrace_event_call *call = &tu->call;
759         struct uprobe_trace_entry_head *entry;
760         struct hlist_head *head;
761         u8 *data;
762         int size, __size, i;
763         int rctx;
764
765         if (!uprobe_perf_filter(&tu->consumer, 0, current->mm))
766                 return UPROBE_HANDLER_REMOVE;
767
768         __size = sizeof(*entry) + tu->size;
769         size = ALIGN(__size + sizeof(u32), sizeof(u64));
770         size -= sizeof(u32);
771         if (WARN_ONCE(size > PERF_MAX_TRACE_SIZE, "profile buffer not large enough"))
772                 return 0;
773
774         preempt_disable();
775
776         entry = perf_trace_buf_prepare(size, call->event.type, regs, &rctx);
777         if (!entry)
778                 goto out;
779
780         entry->ip = instruction_pointer(task_pt_regs(current));
781         data = (u8 *)&entry[1];
782         for (i = 0; i < tu->nr_args; i++)
783                 call_fetch(&tu->args[i].fetch, regs, data + tu->args[i].offset);
784
785         head = this_cpu_ptr(call->perf_events);
786         perf_trace_buf_submit(entry, size, rctx, entry->ip, 1, regs, head, NULL);
787
788  out:
789         preempt_enable();
790         return 0;
791 }
792 #endif  /* CONFIG_PERF_EVENTS */
793
794 static
795 int trace_uprobe_register(struct ftrace_event_call *event, enum trace_reg type, void *data)
796 {
797         struct trace_uprobe *tu = (struct trace_uprobe *)event->data;
798
799         switch (type) {
800         case TRACE_REG_REGISTER:
801                 return probe_event_enable(tu, TP_FLAG_TRACE, NULL);
802
803         case TRACE_REG_UNREGISTER:
804                 probe_event_disable(tu, TP_FLAG_TRACE);
805                 return 0;
806
807 #ifdef CONFIG_PERF_EVENTS
808         case TRACE_REG_PERF_REGISTER:
809                 return probe_event_enable(tu, TP_FLAG_PROFILE, uprobe_perf_filter);
810
811         case TRACE_REG_PERF_UNREGISTER:
812                 probe_event_disable(tu, TP_FLAG_PROFILE);
813                 return 0;
814
815         case TRACE_REG_PERF_OPEN:
816                 return uprobe_perf_open(tu, data);
817
818         case TRACE_REG_PERF_CLOSE:
819                 return uprobe_perf_close(tu, data);
820
821 #endif
822         default:
823                 return 0;
824         }
825         return 0;
826 }
827
828 static int uprobe_dispatcher(struct uprobe_consumer *con, struct pt_regs *regs)
829 {
830         struct trace_uprobe *tu;
831         int ret = 0;
832
833         tu = container_of(con, struct trace_uprobe, consumer);
834         tu->nhit++;
835
836         if (tu->flags & TP_FLAG_TRACE)
837                 ret |= uprobe_trace_func(tu, regs);
838
839 #ifdef CONFIG_PERF_EVENTS
840         if (tu->flags & TP_FLAG_PROFILE)
841                 ret |= uprobe_perf_func(tu, regs);
842 #endif
843         return ret;
844 }
845
846 static struct trace_event_functions uprobe_funcs = {
847         .trace          = print_uprobe_event
848 };
849
850 static int register_uprobe_event(struct trace_uprobe *tu)
851 {
852         struct ftrace_event_call *call = &tu->call;
853         int ret;
854
855         /* Initialize ftrace_event_call */
856         INIT_LIST_HEAD(&call->class->fields);
857         call->event.funcs = &uprobe_funcs;
858         call->class->define_fields = uprobe_event_define_fields;
859
860         if (set_print_fmt(tu) < 0)
861                 return -ENOMEM;
862
863         ret = register_ftrace_event(&call->event);
864         if (!ret) {
865                 kfree(call->print_fmt);
866                 return -ENODEV;
867         }
868         call->flags = 0;
869         call->class->reg = trace_uprobe_register;
870         call->data = tu;
871         ret = trace_add_event_call(call);
872
873         if (ret) {
874                 pr_info("Failed to register uprobe event: %s\n", call->name);
875                 kfree(call->print_fmt);
876                 unregister_ftrace_event(&call->event);
877         }
878
879         return ret;
880 }
881
882 static void unregister_uprobe_event(struct trace_uprobe *tu)
883 {
884         /* tu->event is unregistered in trace_remove_event_call() */
885         trace_remove_event_call(&tu->call);
886         kfree(tu->call.print_fmt);
887         tu->call.print_fmt = NULL;
888 }
889
890 /* Make a trace interface for controling probe points */
891 static __init int init_uprobe_trace(void)
892 {
893         struct dentry *d_tracer;
894
895         d_tracer = tracing_init_dentry();
896         if (!d_tracer)
897                 return 0;
898
899         trace_create_file("uprobe_events", 0644, d_tracer,
900                                     NULL, &uprobe_events_ops);
901         /* Profile interface */
902         trace_create_file("uprobe_profile", 0444, d_tracer,
903                                     NULL, &uprobe_profile_ops);
904         return 0;
905 }
906
907 fs_initcall(init_uprobe_trace);