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 void 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;
 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
 519 /* Event entry printers */
 520 static enum print_line_t
 521 print_uprobe_event(struct trace_iterator *iter, int flags, struct trace_event *event)
 522 {
 523         struct uprobe_trace_entry_head *field;
 524         struct trace_seq *s = &iter->seq;
 525         struct trace_uprobe *tu;
 526         u8 *data;
 527         int i;
 528
 529         field = (struct uprobe_trace_entry_head *)iter->ent;
 530         tu = container_of(event, struct trace_uprobe, call.event);
 531
 532         if (!trace_seq_printf(s, "%s: (", tu->call.name))
 533                 goto partial;
 534
 535         if (!seq_print_ip_sym(s, field->ip, flags | TRACE_ITER_SYM_OFFSET))
 536                 goto partial;
 537
 538         if (!trace_seq_puts(s, ")"))
 539                 goto partial;
 540
 541         data = (u8 *)&field[1];
 542         for (i = 0; i < tu->nr_args; i++) {
 543                 if (!tu->args[i].type->print(s, tu->args[i].name,
 544                                              data + tu->args[i].offset, field))
 545                         goto partial;
 546         }
 547
 548         if (trace_seq_puts(s, "\n"))
 549                 return TRACE_TYPE_HANDLED;
 550
 551 partial:
 552         return TRACE_TYPE_PARTIAL_LINE;
 553 }
 554
 555 static inline bool is_trace_uprobe_enabled(struct trace_uprobe *tu)
 556 {
 557         return tu->flags & (TP_FLAG_TRACE | TP_FLAG_PROFILE);
 558 }
 559
 560 static int probe_event_enable(struct trace_uprobe *tu, int flag)
 561 {
 562         int ret = 0;
 563
 564         if (is_trace_uprobe_enabled(tu))
 565                 return -EINTR;
 566
 567         WARN_ON(!uprobe_filter_is_empty(&tu->filter));
 568
 569         tu->flags |= flag;
 570         ret = uprobe_register(tu->inode, tu->offset, &tu->consumer);
 571         if (ret)
 572                 tu->flags &= ~flag;
 573
 574         return ret;
 575 }
 576
 577 static void probe_event_disable(struct trace_uprobe *tu, int flag)
 578 {
 579         if (!is_trace_uprobe_enabled(tu))
 580                 return;
 581
 582         WARN_ON(!uprobe_filter_is_empty(&tu->filter));
 583
 584         uprobe_unregister(tu->inode, tu->offset, &tu->consumer);
 585         tu->flags &= ~flag;
 586 }
 587
 588 static int uprobe_event_define_fields(struct ftrace_event_call *event_call)
 589 {
 590         int ret, i;
 591         struct uprobe_trace_entry_head field;
 592         struct trace_uprobe *tu = (struct trace_uprobe *)event_call->data;
 593
 594         DEFINE_FIELD(unsigned long, ip, FIELD_STRING_IP, 0);
 595         /* Set argument names as fields */
 596         for (i = 0; i < tu->nr_args; i++) {
 597                 ret = trace_define_field(event_call, tu->args[i].type->fmttype,
 598                                          tu->args[i].name,
 599                                          sizeof(field) + tu->args[i].offset,
 600                                          tu->args[i].type->size,
 601                                          tu->args[i].type->is_signed,
 602                                          FILTER_OTHER);
 603
 604                 if (ret)
 605                         return ret;
 606         }
 607         return 0;
 608 }
 609
 610 #define LEN_OR_ZERO             (len ? len - pos : 0)
 611 static int __set_print_fmt(struct trace_uprobe *tu, char *buf, int len)
 612 {
 613         const char *fmt, *arg;
 614         int i;
 615         int pos = 0;
 616
 617         fmt = "(%lx)";
 618         arg = "REC->" FIELD_STRING_IP;
 619
 620         /* When len=0, we just calculate the needed length */
 621
 622         pos += snprintf(buf + pos, LEN_OR_ZERO, "\"%s", fmt);
 623
 624         for (i = 0; i < tu->nr_args; i++) {
 625                 pos += snprintf(buf + pos, LEN_OR_ZERO, " %s=%s",
 626                                 tu->args[i].name, tu->args[i].type->fmt);
 627         }
 628
 629         pos += snprintf(buf + pos, LEN_OR_ZERO, "\", %s", arg);
 630
 631         for (i = 0; i < tu->nr_args; i++) {
 632                 pos += snprintf(buf + pos, LEN_OR_ZERO, ", REC->%s",
 633                                 tu->args[i].name);
 634         }
 635
 636         return pos;     /* return the length of print_fmt */
 637 }
 638 #undef LEN_OR_ZERO
 639
 640 static int set_print_fmt(struct trace_uprobe *tu)
 641 {
 642         char *print_fmt;
 643         int len;
 644
 645         /* First: called with 0 length to calculate the needed length */
 646         len = __set_print_fmt(tu, NULL, 0);
 647         print_fmt = kmalloc(len + 1, GFP_KERNEL);
 648         if (!print_fmt)
 649                 return -ENOMEM;
 650
 651         /* Second: actually write the @print_fmt */
 652         __set_print_fmt(tu, print_fmt, len + 1);
 653         tu->call.print_fmt = print_fmt;
 654
 655         return 0;
 656 }
 657
 658 #ifdef CONFIG_PERF_EVENTS
 659 static int uprobe_perf_open(struct trace_uprobe *tu, struct perf_event *event)
 660 {
 661         write_lock(&tu->filter.rwlock);
 662         if (event->hw.tp_target)
 663                 list_add(&event->hw.tp_list, &tu->filter.perf_events);
 664         else
 665                 tu->filter.nr_systemwide++;
 666         write_unlock(&tu->filter.rwlock);
 667
 668         return 0;
 669 }
 670
 671 static int uprobe_perf_close(struct trace_uprobe *tu, struct perf_event *event)
 672 {
 673         write_lock(&tu->filter.rwlock);
 674         if (event->hw.tp_target)
 675                 list_del(&event->hw.tp_list);
 676         else
 677                 tu->filter.nr_systemwide--;
 678         write_unlock(&tu->filter.rwlock);
 679
 680         return 0;
 681 }
 682
 683 /* uprobe profile handler */
 684 static void uprobe_perf_func(struct trace_uprobe *tu, struct pt_regs *regs)
 685 {
 686         struct ftrace_event_call *call = &tu->call;
 687         struct uprobe_trace_entry_head *entry;
 688         struct hlist_head *head;
 689         u8 *data;
 690         int size, __size, i;
 691         int rctx;
 692
 693         __size = sizeof(*entry) + tu->size;
 694         size = ALIGN(__size + sizeof(u32), sizeof(u64));
 695         size -= sizeof(u32);
 696         if (WARN_ONCE(size > PERF_MAX_TRACE_SIZE, "profile buffer not large enough"))
 697                 return;
 698
 699         preempt_disable();
 700
 701         entry = perf_trace_buf_prepare(size, call->event.type, regs, &rctx);
 702         if (!entry)
 703                 goto out;
 704
 705         entry->ip = instruction_pointer(task_pt_regs(current));
 706         data = (u8 *)&entry[1];
 707         for (i = 0; i < tu->nr_args; i++)
 708                 call_fetch(&tu->args[i].fetch, regs, data + tu->args[i].offset);
 709
 710         head = this_cpu_ptr(call->perf_events);
 711         perf_trace_buf_submit(entry, size, rctx, entry->ip, 1, regs, head, NULL);
 712
 713  out:
 714         preempt_enable();
 715 }
 716 #endif  /* CONFIG_PERF_EVENTS */
 717
 718 static
 719 int trace_uprobe_register(struct ftrace_event_call *event, enum trace_reg type, void *data)
 720 {
 721         struct trace_uprobe *tu = (struct trace_uprobe *)event->data;
 722
 723         switch (type) {
 724         case TRACE_REG_REGISTER:
 725                 return probe_event_enable(tu, TP_FLAG_TRACE);
 726
 727         case TRACE_REG_UNREGISTER:
 728                 probe_event_disable(tu, TP_FLAG_TRACE);
 729                 return 0;
 730
 731 #ifdef CONFIG_PERF_EVENTS
 732         case TRACE_REG_PERF_REGISTER:
 733                 return probe_event_enable(tu, TP_FLAG_PROFILE);
 734
 735         case TRACE_REG_PERF_UNREGISTER:
 736                 probe_event_disable(tu, TP_FLAG_PROFILE);
 737                 return 0;
 738
 739         case TRACE_REG_PERF_OPEN:
 740                 return uprobe_perf_open(tu, data);
 741
 742         case TRACE_REG_PERF_CLOSE:
 743                 return uprobe_perf_close(tu, data);
 744
 745 #endif
 746         default:
 747                 return 0;
 748         }
 749         return 0;
 750 }
 751
 752 static int uprobe_dispatcher(struct uprobe_consumer *con, struct pt_regs *regs)
 753 {
 754         struct trace_uprobe *tu;
 755
 756         tu = container_of(con, struct trace_uprobe, consumer);
 757         tu->nhit++;
 758
 759         if (tu->flags & TP_FLAG_TRACE)
 760                 uprobe_trace_func(tu, regs);
 761
 762 #ifdef CONFIG_PERF_EVENTS
 763         if (tu->flags & TP_FLAG_PROFILE)
 764                 uprobe_perf_func(tu, regs);
 765 #endif
 766         return 0;
 767 }
 768
 769 static struct trace_event_functions uprobe_funcs = {
 770         .trace          = print_uprobe_event
 771 };
 772
 773 static int register_uprobe_event(struct trace_uprobe *tu)
 774 {
 775         struct ftrace_event_call *call = &tu->call;
 776         int ret;
 777
 778         /* Initialize ftrace_event_call */
 779         INIT_LIST_HEAD(&call->class->fields);
 780         call->event.funcs = &uprobe_funcs;
 781         call->class->define_fields = uprobe_event_define_fields;
 782
 783         if (set_print_fmt(tu) < 0)
 784                 return -ENOMEM;
 785
 786         ret = register_ftrace_event(&call->event);
 787         if (!ret) {
 788                 kfree(call->print_fmt);
 789                 return -ENODEV;
 790         }
 791         call->flags = 0;
 792         call->class->reg = trace_uprobe_register;
 793         call->data = tu;
 794         ret = trace_add_event_call(call);
 795
 796         if (ret) {
 797                 pr_info("Failed to register uprobe event: %s\n", call->name);
 798                 kfree(call->print_fmt);
 799                 unregister_ftrace_event(&call->event);
 800         }
 801
 802         return ret;
 803 }
 804
 805 static void unregister_uprobe_event(struct trace_uprobe *tu)
 806 {
 807         /* tu->event is unregistered in trace_remove_event_call() */
 808         trace_remove_event_call(&tu->call);
 809         kfree(tu->call.print_fmt);
 810         tu->call.print_fmt = NULL;
 811 }
 812
 813 /* Make a trace interface for controling probe points */
 814 static __init int init_uprobe_trace(void)
 815 {
 816         struct dentry *d_tracer;
 817
 818         d_tracer = tracing_init_dentry();
 819         if (!d_tracer)
 820                 return 0;
 821
 822         trace_create_file("uprobe_events", 0644, d_tracer,
 823                                     NULL, &uprobe_events_ops);
 824         /* Profile interface */
 825         trace_create_file("uprobe_profile", 0444, d_tracer,
 826                                     NULL, &uprobe_profile_ops);
 827         return 0;
 828 }
 829
 830 fs_initcall(init_uprobe_trace);