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);