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
  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', 'r' 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);