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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
26 #include "trace_probe.h"
27
28 #define UPROBE_EVENT_SYSTEM     "uprobes"
29
30 /*
31  * uprobe event core functions
32  */
33 struct trace_uprobe;
34 struct uprobe_trace_consumer {
35         struct uprobe_consumer          cons;
36         struct trace_uprobe             *tu;
37 };
38
39 struct trace_uprobe {
40         struct list_head                list;
41         struct ftrace_event_class       class;
42         struct ftrace_event_call        call;
43         struct uprobe_trace_consumer    *consumer;
44         struct inode                    *inode;
45         char                            *filename;
46         unsigned long                   offset;
47         unsigned long                   nhit;
48         unsigned int                    flags;  /* For TP_FLAG_* */
49         ssize_t                         size;   /* trace entry size */
50         unsigned int                    nr_args;
51         struct probe_arg                args[];
52 };
53
54 #define SIZEOF_TRACE_UPROBE(n)                  \
55         (offsetof(struct trace_uprobe, args) +  \
56         (sizeof(struct probe_arg) * (n)))
57
58 static int register_uprobe_event(struct trace_uprobe *tu);
59 static void unregister_uprobe_event(struct trace_uprobe *tu);
60
61 static DEFINE_MUTEX(uprobe_lock);
62 static LIST_HEAD(uprobe_list);
63
64 static int uprobe_dispatcher(struct uprobe_consumer *con, struct pt_regs *regs);
65
66 /*
67  * Allocate new trace_uprobe and initialize it (including uprobes).
68  */
69 static struct trace_uprobe *
70 alloc_trace_uprobe(const char *group, const char *event, int nargs)
71 {
72         struct trace_uprobe *tu;
73
74         if (!event || !is_good_name(event))
75                 return ERR_PTR(-EINVAL);
76
77         if (!group || !is_good_name(group))
78                 return ERR_PTR(-EINVAL);
79
80         tu = kzalloc(SIZEOF_TRACE_UPROBE(nargs), GFP_KERNEL);
81         if (!tu)
82                 return ERR_PTR(-ENOMEM);
83
84         tu->call.class = &tu->class;
85         tu->call.name = kstrdup(event, GFP_KERNEL);
86         if (!tu->call.name)
87                 goto error;
88
89         tu->class.system = kstrdup(group, GFP_KERNEL);
90         if (!tu->class.system)
91                 goto error;
92
93         INIT_LIST_HEAD(&tu->list);
94         return tu;
95
96 error:
97         kfree(tu->call.name);
98         kfree(tu);
99
100         return ERR_PTR(-ENOMEM);
101 }
102
103 static void free_trace_uprobe(struct trace_uprobe *tu)
104 {
105         int i;
106
107         for (i = 0; i < tu->nr_args; i++)
108                 traceprobe_free_probe_arg(&tu->args[i]);
109
110         iput(tu->inode);
111         kfree(tu->call.class->system);
112         kfree(tu->call.name);
113         kfree(tu->filename);
114         kfree(tu);
115 }
116
117 static struct trace_uprobe *find_probe_event(const char *event, const char *group)
118 {
119         struct trace_uprobe *tu;
120
121         list_for_each_entry(tu, &uprobe_list, list)
122                 if (strcmp(tu->call.name, event) == 0 &&
123                     strcmp(tu->call.class->system, group) == 0)
124                         return tu;
125
126         return NULL;
127 }
128
129 /* Unregister a trace_uprobe and probe_event: call with locking uprobe_lock */
130 static void unregister_trace_uprobe(struct trace_uprobe *tu)
131 {
132         list_del(&tu->list);
133         unregister_uprobe_event(tu);
134         free_trace_uprobe(tu);
135 }
136
137 /* Register a trace_uprobe and probe_event */
138 static int register_trace_uprobe(struct trace_uprobe *tu)
139 {
140         struct trace_uprobe *old_tp;
141         int ret;
142
143         mutex_lock(&uprobe_lock);
144
145         /* register as an event */
146         old_tp = find_probe_event(tu->call.name, tu->call.class->system);
147         if (old_tp)
148                 /* delete old event */
149                 unregister_trace_uprobe(old_tp);
150
151         ret = register_uprobe_event(tu);
152         if (ret) {
153                 pr_warning("Failed to register probe event(%d)\n", ret);
154                 goto end;
155         }
156
157         list_add_tail(&tu->list, &uprobe_list);
158
159 end:
160         mutex_unlock(&uprobe_lock);
161
162         return ret;
163 }
164
165 /*
166  * Argument syntax:
167  *  - Add uprobe: p[:[GRP/]EVENT] PATH:SYMBOL[+offs] [FETCHARGS]
168  *
169  *  - Remove uprobe: -:[GRP/]EVENT
170  */
171 static int create_trace_uprobe(int argc, char **argv)
172 {
173         struct trace_uprobe *tu;
174         struct inode *inode;
175         char *arg, *event, *group, *filename;
176         char buf[MAX_EVENT_NAME_LEN];
177         struct path path;
178         unsigned long offset;
179         bool is_delete;
180         int i, ret;
181
182         inode = NULL;
183         ret = 0;
184         is_delete = false;
185         event = NULL;
186         group = NULL;
187
188         /* argc must be >= 1 */
189         if (argv[0][0] == '-')
190                 is_delete = true;
191         else if (argv[0][0] != 'p') {
192                 pr_info("Probe definition must be started with 'p' or '-'.\n");
193                 return -EINVAL;
194         }
195
196         if (argv[0][1] == ':') {
197                 event = &argv[0][2];
198                 arg = strchr(event, '/');
199
200                 if (arg) {
201                         group = event;
202                         event = arg + 1;
203                         event[-1] = '\0';
204
205                         if (strlen(group) == 0) {
206                                 pr_info("Group name is not specified\n");
207                                 return -EINVAL;
208                         }
209                 }
210                 if (strlen(event) == 0) {
211                         pr_info("Event name is not specified\n");
212                         return -EINVAL;
213                 }
214         }
215         if (!group)
216                 group = UPROBE_EVENT_SYSTEM;
217
218         if (is_delete) {
219                 if (!event) {
220                         pr_info("Delete command needs an event name.\n");
221                         return -EINVAL;
222                 }
223                 mutex_lock(&uprobe_lock);
224                 tu = find_probe_event(event, group);
225
226                 if (!tu) {
227                         mutex_unlock(&uprobe_lock);
228                         pr_info("Event %s/%s doesn't exist.\n", group, event);
229                         return -ENOENT;
230                 }
231                 /* delete an event */
232                 unregister_trace_uprobe(tu);
233                 mutex_unlock(&uprobe_lock);
234                 return 0;
235         }
236
237         if (argc < 2) {
238                 pr_info("Probe point is not specified.\n");
239                 return -EINVAL;
240         }
241         if (isdigit(argv[1][0])) {
242                 pr_info("probe point must be have a filename.\n");
243                 return -EINVAL;
244         }
245         arg = strchr(argv[1], ':');
246         if (!arg)
247                 goto fail_address_parse;
248
249         *arg++ = '\0';
250         filename = argv[1];
251         ret = kern_path(filename, LOOKUP_FOLLOW, &path);
252         if (ret)
253                 goto fail_address_parse;
254
255         ret = strict_strtoul(arg, 0, &offset);
256         if (ret)
257                 goto fail_address_parse;
258
259         inode = igrab(path.dentry->d_inode);
260
261         argc -= 2;
262         argv += 2;
263
264         /* setup a probe */
265         if (!event) {
266                 char *tail = strrchr(filename, '/');
267                 char *ptr;
268
269                 ptr = kstrdup((tail ? tail + 1 : filename), GFP_KERNEL);
270                 if (!ptr) {
271                         ret = -ENOMEM;
272                         goto fail_address_parse;
273                 }
274
275                 tail = ptr;
276                 ptr = strpbrk(tail, ".-_");
277                 if (ptr)
278                         *ptr = '\0';
279
280                 snprintf(buf, MAX_EVENT_NAME_LEN, "%c_%s_0x%lx", 'p', tail, offset);
281                 event = buf;
282                 kfree(tail);
283         }
284
285         tu = alloc_trace_uprobe(group, event, argc);
286         if (IS_ERR(tu)) {
287                 pr_info("Failed to allocate trace_uprobe.(%d)\n", (int)PTR_ERR(tu));
288                 ret = PTR_ERR(tu);
289                 goto fail_address_parse;
290         }
291         tu->offset = offset;
292         tu->inode = inode;
293         tu->filename = kstrdup(filename, GFP_KERNEL);
294
295         if (!tu->filename) {
296                 pr_info("Failed to allocate filename.\n");
297                 ret = -ENOMEM;
298                 goto error;
299         }
300
301         /* parse arguments */
302         ret = 0;
303         for (i = 0; i < argc && i < MAX_TRACE_ARGS; i++) {
304                 /* Increment count for freeing args in error case */
305                 tu->nr_args++;
306
307                 /* Parse argument name */
308                 arg = strchr(argv[i], '=');
309                 if (arg) {
310                         *arg++ = '\0';
311                         tu->args[i].name = kstrdup(argv[i], GFP_KERNEL);
312                 } else {
313                         arg = argv[i];
314                         /* If argument name is omitted, set "argN" */
315                         snprintf(buf, MAX_EVENT_NAME_LEN, "arg%d", i + 1);
316                         tu->args[i].name = kstrdup(buf, GFP_KERNEL);
317                 }
318
319                 if (!tu->args[i].name) {
320                         pr_info("Failed to allocate argument[%d] name.\n", i);
321                         ret = -ENOMEM;
322                         goto error;
323                 }
324
325                 if (!is_good_name(tu->args[i].name)) {
326                         pr_info("Invalid argument[%d] name: %s\n", i, tu->args[i].name);
327                         ret = -EINVAL;
328                         goto error;
329                 }
330
331                 if (traceprobe_conflict_field_name(tu->args[i].name, tu->args, i)) {
332                         pr_info("Argument[%d] name '%s' conflicts with "
333                                 "another field.\n", i, argv[i]);
334                         ret = -EINVAL;
335                         goto error;
336                 }
337
338                 /* Parse fetch argument */
339                 ret = traceprobe_parse_probe_arg(arg, &tu->size, &tu->args[i], false, false);
340                 if (ret) {
341                         pr_info("Parse error at argument[%d]. (%d)\n", i, ret);
342                         goto error;
343                 }
344         }
345
346         ret = register_trace_uprobe(tu);
347         if (ret)
348                 goto error;
349         return 0;
350
351 error:
352         free_trace_uprobe(tu);
353         return ret;
354
355 fail_address_parse:
356         if (inode)
357                 iput(inode);
358
359         pr_info("Failed to parse address.\n");
360
361         return ret;
362 }
363
364 static void cleanup_all_probes(void)
365 {
366         struct trace_uprobe *tu;
367
368         mutex_lock(&uprobe_lock);
369         while (!list_empty(&uprobe_list)) {
370                 tu = list_entry(uprobe_list.next, struct trace_uprobe, list);
371                 unregister_trace_uprobe(tu);
372         }
373         mutex_unlock(&uprobe_lock);
374 }
375
376 /* Probes listing interfaces */
377 static void *probes_seq_start(struct seq_file *m, loff_t *pos)
378 {
379         mutex_lock(&uprobe_lock);
380         return seq_list_start(&uprobe_list, *pos);
381 }
382
383 static void *probes_seq_next(struct seq_file *m, void *v, loff_t *pos)
384 {
385         return seq_list_next(v, &uprobe_list, pos);
386 }
387
388 static void probes_seq_stop(struct seq_file *m, void *v)
389 {
390         mutex_unlock(&uprobe_lock);
391 }
392
393 static int probes_seq_show(struct seq_file *m, void *v)
394 {
395         struct trace_uprobe *tu = v;
396         int i;
397
398         seq_printf(m, "p:%s/%s", tu->call.class->system, tu->call.name);
399         seq_printf(m, " %s:0x%p", tu->filename, (void *)tu->offset);
400
401         for (i = 0; i < tu->nr_args; i++)
402                 seq_printf(m, " %s=%s", tu->args[i].name, tu->args[i].comm);
403
404         seq_printf(m, "\n");
405         return 0;
406 }
407
408 static const struct seq_operations probes_seq_op = {
409         .start  = probes_seq_start,
410         .next   = probes_seq_next,
411         .stop   = probes_seq_stop,
412         .show   = probes_seq_show
413 };
414
415 static int probes_open(struct inode *inode, struct file *file)
416 {
417         if ((file->f_mode & FMODE_WRITE) && (file->f_flags & O_TRUNC))
418                 cleanup_all_probes();
419
420         return seq_open(file, &probes_seq_op);
421 }
422
423 static ssize_t probes_write(struct file *file, const char __user *buffer,
424                             size_t count, loff_t *ppos)
425 {
426         return traceprobe_probes_write(file, buffer, count, ppos, create_trace_uprobe);
427 }
428
429 static const struct file_operations uprobe_events_ops = {
430         .owner          = THIS_MODULE,
431         .open           = probes_open,
432         .read           = seq_read,
433         .llseek         = seq_lseek,
434         .release        = seq_release,
435         .write          = probes_write,
436 };
437
438 /* Probes profiling interfaces */
439 static int probes_profile_seq_show(struct seq_file *m, void *v)
440 {
441         struct trace_uprobe *tu = v;
442
443         seq_printf(m, "  %s %-44s %15lu\n", tu->filename, tu->call.name, tu->nhit);
444         return 0;
445 }
446
447 static const struct seq_operations profile_seq_op = {
448         .start  = probes_seq_start,
449         .next   = probes_seq_next,
450         .stop   = probes_seq_stop,
451         .show   = probes_profile_seq_show
452 };
453
454 static int profile_open(struct inode *inode, struct file *file)
455 {
456         return seq_open(file, &profile_seq_op);
457 }
458
459 static const struct file_operations uprobe_profile_ops = {
460         .owner          = THIS_MODULE,
461         .open           = profile_open,
462         .read           = seq_read,
463         .llseek         = seq_lseek,
464         .release        = seq_release,
465 };
466
467 /* uprobe handler */
468 static void uprobe_trace_func(struct trace_uprobe *tu, struct pt_regs *regs)
469 {
470         struct uprobe_trace_entry_head *entry;
471         struct ring_buffer_event *event;
472         struct ring_buffer *buffer;
473         u8 *data;
474         int size, i, pc;
475         unsigned long irq_flags;
476         struct ftrace_event_call *call = &tu->call;
477
478         tu->nhit++;
479
480         local_save_flags(irq_flags);
481         pc = preempt_count();
482
483         size = sizeof(*entry) + tu->size;
484
485         event = trace_current_buffer_lock_reserve(&buffer, call->event.type,
486                                                   size, irq_flags, pc);
487         if (!event)
488                 return;
489
490         entry = ring_buffer_event_data(event);
491         entry->ip = uprobe_get_swbp_addr(task_pt_regs(current));
492         data = (u8 *)&entry[1];
493         for (i = 0; i < tu->nr_args; i++)
494                 call_fetch(&tu->args[i].fetch, regs, data + tu->args[i].offset);
495
496         if (!filter_current_check_discard(buffer, call, entry, event))
497                 trace_buffer_unlock_commit(buffer, event, irq_flags, pc);
498 }
499
500 /* Event entry printers */
501 static enum print_line_t
502 print_uprobe_event(struct trace_iterator *iter, int flags, struct trace_event *event)
503 {
504         struct uprobe_trace_entry_head *field;
505         struct trace_seq *s = &iter->seq;
506         struct trace_uprobe *tu;
507         u8 *data;
508         int i;
509
510         field = (struct uprobe_trace_entry_head *)iter->ent;
511         tu = container_of(event, struct trace_uprobe, call.event);
512
513         if (!trace_seq_printf(s, "%s: (", tu->call.name))
514                 goto partial;
515
516         if (!seq_print_ip_sym(s, field->ip, flags | TRACE_ITER_SYM_OFFSET))
517                 goto partial;
518
519         if (!trace_seq_puts(s, ")"))
520                 goto partial;
521
522         data = (u8 *)&field[1];
523         for (i = 0; i < tu->nr_args; i++) {
524                 if (!tu->args[i].type->print(s, tu->args[i].name,
525                                              data + tu->args[i].offset, field))
526                         goto partial;
527         }
528
529         if (trace_seq_puts(s, "\n"))
530                 return TRACE_TYPE_HANDLED;
531
532 partial:
533         return TRACE_TYPE_PARTIAL_LINE;
534 }
535
536 static int probe_event_enable(struct trace_uprobe *tu, int flag)
537 {
538         struct uprobe_trace_consumer *utc;
539         int ret = 0;
540
541         if (!tu->inode || tu->consumer)
542                 return -EINTR;
543
544         utc = kzalloc(sizeof(struct uprobe_trace_consumer), GFP_KERNEL);
545         if (!utc)
546                 return -EINTR;
547
548         utc->cons.handler = uprobe_dispatcher;
549         utc->cons.filter = NULL;
550         ret = uprobe_register(tu->inode, tu->offset, &utc->cons);
551         if (ret) {
552                 kfree(utc);
553                 return ret;
554         }
555
556         tu->flags |= flag;
557         utc->tu = tu;
558         tu->consumer = utc;
559
560         return 0;
561 }
562
563 static void probe_event_disable(struct trace_uprobe *tu, int flag)
564 {
565         if (!tu->inode || !tu->consumer)
566                 return;
567
568         uprobe_unregister(tu->inode, tu->offset, &tu->consumer->cons);
569         tu->flags &= ~flag;
570         kfree(tu->consumer);
571         tu->consumer = NULL;
572 }
573
574 static int uprobe_event_define_fields(struct ftrace_event_call *event_call)
575 {
576         int ret, i;
577         struct uprobe_trace_entry_head field;
578         struct trace_uprobe *tu = (struct trace_uprobe *)event_call->data;
579
580         DEFINE_FIELD(unsigned long, ip, FIELD_STRING_IP, 0);
581         /* Set argument names as fields */
582         for (i = 0; i < tu->nr_args; i++) {
583                 ret = trace_define_field(event_call, tu->args[i].type->fmttype,
584                                          tu->args[i].name,
585                                          sizeof(field) + tu->args[i].offset,
586                                          tu->args[i].type->size,
587                                          tu->args[i].type->is_signed,
588                                          FILTER_OTHER);
589
590                 if (ret)
591                         return ret;
592         }
593         return 0;
594 }
595
596 #define LEN_OR_ZERO             (len ? len - pos : 0)
597 static int __set_print_fmt(struct trace_uprobe *tu, char *buf, int len)
598 {
599         const char *fmt, *arg;
600         int i;
601         int pos = 0;
602
603         fmt = "(%lx)";
604         arg = "REC->" FIELD_STRING_IP;
605
606         /* When len=0, we just calculate the needed length */
607
608         pos += snprintf(buf + pos, LEN_OR_ZERO, "\"%s", fmt);
609
610         for (i = 0; i < tu->nr_args; i++) {
611                 pos += snprintf(buf + pos, LEN_OR_ZERO, " %s=%s",
612                                 tu->args[i].name, tu->args[i].type->fmt);
613         }
614
615         pos += snprintf(buf + pos, LEN_OR_ZERO, "\", %s", arg);
616
617         for (i = 0; i < tu->nr_args; i++) {
618                 pos += snprintf(buf + pos, LEN_OR_ZERO, ", REC->%s",
619                                 tu->args[i].name);
620         }
621
622         return pos;     /* return the length of print_fmt */
623 }
624 #undef LEN_OR_ZERO
625
626 static int set_print_fmt(struct trace_uprobe *tu)
627 {
628         char *print_fmt;
629         int len;
630
631         /* First: called with 0 length to calculate the needed length */
632         len = __set_print_fmt(tu, NULL, 0);
633         print_fmt = kmalloc(len + 1, GFP_KERNEL);
634         if (!print_fmt)
635                 return -ENOMEM;
636
637         /* Second: actually write the @print_fmt */
638         __set_print_fmt(tu, print_fmt, len + 1);
639         tu->call.print_fmt = print_fmt;
640
641         return 0;
642 }
643
644 #ifdef CONFIG_PERF_EVENTS
645 /* uprobe profile handler */
646 static void uprobe_perf_func(struct trace_uprobe *tu, struct pt_regs *regs)
647 {
648         struct ftrace_event_call *call = &tu->call;
649         struct uprobe_trace_entry_head *entry;
650         struct hlist_head *head;
651         u8 *data;
652         int size, __size, i;
653         int rctx;
654
655         __size = sizeof(*entry) + tu->size;
656         size = ALIGN(__size + sizeof(u32), sizeof(u64));
657         size -= sizeof(u32);
658         if (WARN_ONCE(size > PERF_MAX_TRACE_SIZE, "profile buffer not large enough"))
659                 return;
660
661         preempt_disable();
662
663         entry = perf_trace_buf_prepare(size, call->event.type, regs, &rctx);
664         if (!entry)
665                 goto out;
666
667         entry->ip = uprobe_get_swbp_addr(task_pt_regs(current));
668         data = (u8 *)&entry[1];
669         for (i = 0; i < tu->nr_args; i++)
670                 call_fetch(&tu->args[i].fetch, regs, data + tu->args[i].offset);
671
672         head = this_cpu_ptr(call->perf_events);
673         perf_trace_buf_submit(entry, size, rctx, entry->ip, 1, regs, head, NULL);
674
675  out:
676         preempt_enable();
677 }
678 #endif  /* CONFIG_PERF_EVENTS */
679
680 static
681 int trace_uprobe_register(struct ftrace_event_call *event, enum trace_reg type, void *data)
682 {
683         struct trace_uprobe *tu = (struct trace_uprobe *)event->data;
684
685         switch (type) {
686         case TRACE_REG_REGISTER:
687                 return probe_event_enable(tu, TP_FLAG_TRACE);
688
689         case TRACE_REG_UNREGISTER:
690                 probe_event_disable(tu, TP_FLAG_TRACE);
691                 return 0;
692
693 #ifdef CONFIG_PERF_EVENTS
694         case TRACE_REG_PERF_REGISTER:
695                 return probe_event_enable(tu, TP_FLAG_PROFILE);
696
697         case TRACE_REG_PERF_UNREGISTER:
698                 probe_event_disable(tu, TP_FLAG_PROFILE);
699                 return 0;
700 #endif
701         default:
702                 return 0;
703         }
704         return 0;
705 }
706
707 static int uprobe_dispatcher(struct uprobe_consumer *con, struct pt_regs *regs)
708 {
709         struct uprobe_trace_consumer *utc;
710         struct trace_uprobe *tu;
711
712         utc = container_of(con, struct uprobe_trace_consumer, cons);
713         tu = utc->tu;
714         if (!tu || tu->consumer != utc)
715                 return 0;
716
717         if (tu->flags & TP_FLAG_TRACE)
718                 uprobe_trace_func(tu, regs);
719
720 #ifdef CONFIG_PERF_EVENTS
721         if (tu->flags & TP_FLAG_PROFILE)
722                 uprobe_perf_func(tu, regs);
723 #endif
724         return 0;
725 }
726
727 static struct trace_event_functions uprobe_funcs = {
728         .trace          = print_uprobe_event
729 };
730
731 static int register_uprobe_event(struct trace_uprobe *tu)
732 {
733         struct ftrace_event_call *call = &tu->call;
734         int ret;
735
736         /* Initialize ftrace_event_call */
737         INIT_LIST_HEAD(&call->class->fields);
738         call->event.funcs = &uprobe_funcs;
739         call->class->define_fields = uprobe_event_define_fields;
740
741         if (set_print_fmt(tu) < 0)
742                 return -ENOMEM;
743
744         ret = register_ftrace_event(&call->event);
745         if (!ret) {
746                 kfree(call->print_fmt);
747                 return -ENODEV;
748         }
749         call->flags = 0;
750         call->class->reg = trace_uprobe_register;
751         call->data = tu;
752         ret = trace_add_event_call(call);
753
754         if (ret) {
755                 pr_info("Failed to register uprobe event: %s\n", call->name);
756                 kfree(call->print_fmt);
757                 unregister_ftrace_event(&call->event);
758         }
759
760         return ret;
761 }
762
763 static void unregister_uprobe_event(struct trace_uprobe *tu)
764 {
765         /* tu->event is unregistered in trace_remove_event_call() */
766         trace_remove_event_call(&tu->call);
767         kfree(tu->call.print_fmt);
768         tu->call.print_fmt = NULL;
769 }
770
771 /* Make a trace interface for controling probe points */
772 static __init int init_uprobe_trace(void)
773 {
774         struct dentry *d_tracer;
775
776         d_tracer = tracing_init_dentry();
777         if (!d_tracer)
778                 return 0;
779
780         trace_create_file("uprobe_events", 0644, d_tracer,
781                                     NULL, &uprobe_events_ops);
782         /* Profile interface */
783         trace_create_file("uprobe_profile", 0444, d_tracer,
784                                     NULL, &uprobe_profile_ops);
785         return 0;
786 }
787
788 fs_initcall(init_uprobe_trace);