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 #define pr_fmt(fmt)     "trace_kprobe: " fmt
  21
  22 #include <linux/module.h>
  23 #include <linux/uaccess.h>
  24 #include <linux/uprobes.h>
  25 #include <linux/namei.h>
  26 #include <linux/string.h>
  27 #include <linux/rculist.h>
  28
  29 #include "trace_probe.h"
  30
  31 #define UPROBE_EVENT_SYSTEM     "uprobes"
  32
  33 struct uprobe_trace_entry_head {
  34         struct trace_entry      ent;
  35         unsigned long           vaddr[];
  36 };
  37
  38 #define SIZEOF_TRACE_ENTRY(is_return)                   \
  39         (sizeof(struct uprobe_trace_entry_head) +       \
  40          sizeof(unsigned long) * (is_return ? 2 : 1))
  41
  42 #define DATAOF_TRACE_ENTRY(entry, is_return)            \
  43         ((void*)(entry) + SIZEOF_TRACE_ENTRY(is_return))
  44
  45 struct trace_uprobe_filter {
  46         rwlock_t                rwlock;
  47         int                     nr_systemwide;
  48         struct list_head        perf_events;
  49 };
  50
  51 /*
  52  * uprobe event core functions
  53  */
  54 struct trace_uprobe {
  55         struct list_head                list;
  56         struct trace_uprobe_filter      filter;
  57         struct uprobe_consumer          consumer;
  58         struct inode                    *inode;
  59         char                            *filename;
  60         unsigned long                   offset;
  61         unsigned long                   nhit;
  62         struct trace_probe              tp;
  63 };
  64
  65 #define SIZEOF_TRACE_UPROBE(n)                          \
  66         (offsetof(struct trace_uprobe, tp.args) +       \
  67         (sizeof(struct probe_arg) * (n)))
  68
  69 static int register_uprobe_event(struct trace_uprobe *tu);
  70 static int unregister_uprobe_event(struct trace_uprobe *tu);
  71
  72 static DEFINE_MUTEX(uprobe_lock);
  73 static LIST_HEAD(uprobe_list);
  74
  75 struct uprobe_dispatch_data {
  76         struct trace_uprobe     *tu;
  77         unsigned long           bp_addr;
  78 };
  79
  80 static int uprobe_dispatcher(struct uprobe_consumer *con, struct pt_regs *regs);
  81 static int uretprobe_dispatcher(struct uprobe_consumer *con,
  82                                 unsigned long func, struct pt_regs *regs);
  83
  84 #ifdef CONFIG_STACK_GROWSUP
  85 static unsigned long adjust_stack_addr(unsigned long addr, unsigned int n)
  86 {
  87         return addr - (n * sizeof(long));
  88 }
  89 #else
  90 static unsigned long adjust_stack_addr(unsigned long addr, unsigned int n)
  91 {
  92         return addr + (n * sizeof(long));
  93 }
  94 #endif
  95
  96 static unsigned long get_user_stack_nth(struct pt_regs *regs, unsigned int n)
  97 {
  98         unsigned long ret;
  99         unsigned long addr = user_stack_pointer(regs);
 100
 101         addr = adjust_stack_addr(addr, n);
 102
 103         if (copy_from_user(&ret, (void __force __user *) addr, sizeof(ret)))
 104                 return 0;
 105
 106         return ret;
 107 }
 108
 109 /*
 110  * Uprobes-specific fetch functions
 111  */
 112 #define DEFINE_FETCH_stack(type)                                        \
 113 static void FETCH_FUNC_NAME(stack, type)(struct pt_regs *regs,          \
 114                                          void *offset, void *dest)      \
 115 {                                                                       \
 116         *(type *)dest = (type)get_user_stack_nth(regs,                  \
 117                                               ((unsigned long)offset)); \
 118 }
 119 DEFINE_BASIC_FETCH_FUNCS(stack)
 120 /* No string on the stack entry */
 121 #define fetch_stack_string      NULL
 122 #define fetch_stack_string_size NULL
 123
 124 #define DEFINE_FETCH_memory(type)                                       \
 125 static void FETCH_FUNC_NAME(memory, type)(struct pt_regs *regs,         \
 126                                           void *addr, void *dest)       \
 127 {                                                                       \
 128         type retval;                                                    \
 129         void __user *vaddr = (void __force __user *) addr;              \
 130                                                                         \
 131         if (copy_from_user(&retval, vaddr, sizeof(type)))               \
 132                 *(type *)dest = 0;                                      \
 133         else                                                            \
 134                 *(type *) dest = retval;                                \
 135 }
 136 DEFINE_BASIC_FETCH_FUNCS(memory)
 137 /*
 138  * Fetch a null-terminated string. Caller MUST set *(u32 *)dest with max
 139  * length and relative data location.
 140  */
 141 static void FETCH_FUNC_NAME(memory, string)(struct pt_regs *regs,
 142                                             void *addr, void *dest)
 143 {
 144         long ret;
 145         u32 rloc = *(u32 *)dest;
 146         int maxlen  = get_rloc_len(rloc);
 147         u8 *dst = get_rloc_data(dest);
 148         void __user *src = (void __force __user *) addr;
 149
 150         if (!maxlen)
 151                 return;
 152
 153         ret = strncpy_from_user(dst, src, maxlen);
 154         if (ret == maxlen)
 155                 dst[--ret] = '\0';
 156
 157         if (ret < 0) {  /* Failed to fetch string */
 158                 ((u8 *)get_rloc_data(dest))[0] = '\0';
 159                 *(u32 *)dest = make_data_rloc(0, get_rloc_offs(rloc));
 160         } else {
 161                 *(u32 *)dest = make_data_rloc(ret, get_rloc_offs(rloc));
 162         }
 163 }
 164
 165 static void FETCH_FUNC_NAME(memory, string_size)(struct pt_regs *regs,
 166                                                  void *addr, void *dest)
 167 {
 168         int len;
 169         void __user *vaddr = (void __force __user *) addr;
 170
 171         len = strnlen_user(vaddr, MAX_STRING_SIZE);
 172
 173         if (len == 0 || len > MAX_STRING_SIZE)  /* Failed to check length */
 174                 *(u32 *)dest = 0;
 175         else
 176                 *(u32 *)dest = len;
 177 }
 178
 179 static unsigned long translate_user_vaddr(void *file_offset)
 180 {
 181         unsigned long base_addr;
 182         struct uprobe_dispatch_data *udd;
 183
 184         udd = (void *) current->utask->vaddr;
 185
 186         base_addr = udd->bp_addr - udd->tu->offset;
 187         return base_addr + (unsigned long)file_offset;
 188 }
 189
 190 #define DEFINE_FETCH_file_offset(type)                                  \
 191 static void FETCH_FUNC_NAME(file_offset, type)(struct pt_regs *regs,    \
 192                                                void *offset, void *dest)\
 193 {                                                                       \
 194         void *vaddr = (void *)translate_user_vaddr(offset);             \
 195                                                                         \
 196         FETCH_FUNC_NAME(memory, type)(regs, vaddr, dest);               \
 197 }
 198 DEFINE_BASIC_FETCH_FUNCS(file_offset)
 199 DEFINE_FETCH_file_offset(string)
 200 DEFINE_FETCH_file_offset(string_size)
 201
 202 /* Fetch type information table */
 203 static const struct fetch_type uprobes_fetch_type_table[] = {
 204         /* Special types */
 205         [FETCH_TYPE_STRING] = __ASSIGN_FETCH_TYPE("string", string, string,
 206                                         sizeof(u32), 1, "__data_loc char[]"),
 207         [FETCH_TYPE_STRSIZE] = __ASSIGN_FETCH_TYPE("string_size", u32,
 208                                         string_size, sizeof(u32), 0, "u32"),
 209         /* Basic types */
 210         ASSIGN_FETCH_TYPE(u8,  u8,  0),
 211         ASSIGN_FETCH_TYPE(u16, u16, 0),
 212         ASSIGN_FETCH_TYPE(u32, u32, 0),
 213         ASSIGN_FETCH_TYPE(u64, u64, 0),
 214         ASSIGN_FETCH_TYPE(s8,  u8,  1),
 215         ASSIGN_FETCH_TYPE(s16, u16, 1),
 216         ASSIGN_FETCH_TYPE(s32, u32, 1),
 217         ASSIGN_FETCH_TYPE(s64, u64, 1),
 218         ASSIGN_FETCH_TYPE_ALIAS(x8,  u8,  u8,  0),
 219         ASSIGN_FETCH_TYPE_ALIAS(x16, u16, u16, 0),
 220         ASSIGN_FETCH_TYPE_ALIAS(x32, u32, u32, 0),
 221         ASSIGN_FETCH_TYPE_ALIAS(x64, u64, u64, 0),
 222
 223         ASSIGN_FETCH_TYPE_END
 224 };
 225
 226 static inline void init_trace_uprobe_filter(struct trace_uprobe_filter *filter)
 227 {
 228         rwlock_init(&filter->rwlock);
 229         filter->nr_systemwide = 0;
 230         INIT_LIST_HEAD(&filter->perf_events);
 231 }
 232
 233 static inline bool uprobe_filter_is_empty(struct trace_uprobe_filter *filter)
 234 {
 235         return !filter->nr_systemwide && list_empty(&filter->perf_events);
 236 }
 237
 238 static inline bool is_ret_probe(struct trace_uprobe *tu)
 239 {
 240         return tu->consumer.ret_handler != NULL;
 241 }
 242
 243 /*
 244  * Allocate new trace_uprobe and initialize it (including uprobes).
 245  */
 246 static struct trace_uprobe *
 247 alloc_trace_uprobe(const char *group, const char *event, int nargs, bool is_ret)
 248 {
 249         struct trace_uprobe *tu;
 250
 251         if (!event || !is_good_name(event))
 252                 return ERR_PTR(-EINVAL);
 253
 254         if (!group || !is_good_name(group))
 255                 return ERR_PTR(-EINVAL);
 256
 257         tu = kzalloc(SIZEOF_TRACE_UPROBE(nargs), GFP_KERNEL);
 258         if (!tu)
 259                 return ERR_PTR(-ENOMEM);
 260
 261         tu->tp.call.class = &tu->tp.class;
 262         tu->tp.call.name = kstrdup(event, GFP_KERNEL);
 263         if (!tu->tp.call.name)
 264                 goto error;
 265
 266         tu->tp.class.system = kstrdup(group, GFP_KERNEL);
 267         if (!tu->tp.class.system)
 268                 goto error;
 269
 270         INIT_LIST_HEAD(&tu->list);
 271         INIT_LIST_HEAD(&tu->tp.files);
 272         tu->consumer.handler = uprobe_dispatcher;
 273         if (is_ret)
 274                 tu->consumer.ret_handler = uretprobe_dispatcher;
 275         init_trace_uprobe_filter(&tu->filter);
 276         return tu;
 277
 278 error:
 279         kfree(tu->tp.call.name);
 280         kfree(tu);
 281
 282         return ERR_PTR(-ENOMEM);
 283 }
 284
 285 static void free_trace_uprobe(struct trace_uprobe *tu)
 286 {
 287         int i;
 288
 289         for (i = 0; i < tu->tp.nr_args; i++)
 290                 traceprobe_free_probe_arg(&tu->tp.args[i]);
 291
 292         iput(tu->inode);
 293         kfree(tu->tp.call.class->system);
 294         kfree(tu->tp.call.name);
 295         kfree(tu->filename);
 296         kfree(tu);
 297 }
 298
 299 static struct trace_uprobe *find_probe_event(const char *event, const char *group)
 300 {
 301         struct trace_uprobe *tu;
 302
 303         list_for_each_entry(tu, &uprobe_list, list)
 304                 if (strcmp(trace_event_name(&tu->tp.call), event) == 0 &&
 305                     strcmp(tu->tp.call.class->system, group) == 0)
 306                         return tu;
 307
 308         return NULL;
 309 }
 310
 311 /* Unregister a trace_uprobe and probe_event: call with locking uprobe_lock */
 312 static int unregister_trace_uprobe(struct trace_uprobe *tu)
 313 {
 314         int ret;
 315
 316         ret = unregister_uprobe_event(tu);
 317         if (ret)
 318                 return ret;
 319
 320         list_del(&tu->list);
 321         free_trace_uprobe(tu);
 322         return 0;
 323 }
 324
 325 /* Register a trace_uprobe and probe_event */
 326 static int register_trace_uprobe(struct trace_uprobe *tu)
 327 {
 328         struct trace_uprobe *old_tu;
 329         int ret;
 330
 331         mutex_lock(&uprobe_lock);
 332
 333         /* register as an event */
 334         old_tu = find_probe_event(trace_event_name(&tu->tp.call),
 335                         tu->tp.call.class->system);
 336         if (old_tu) {
 337                 /* delete old event */
 338                 ret = unregister_trace_uprobe(old_tu);
 339                 if (ret)
 340                         goto end;
 341         }
 342
 343         ret = register_uprobe_event(tu);
 344         if (ret) {
 345                 pr_warn("Failed to register probe event(%d)\n", ret);
 346                 goto end;
 347         }
 348
 349         list_add_tail(&tu->list, &uprobe_list);
 350
 351 end:
 352         mutex_unlock(&uprobe_lock);
 353
 354         return ret;
 355 }
 356
 357 /*
 358  * Argument syntax:
 359  *  - Add uprobe: p|r[:[GRP/]EVENT] PATH:OFFSET [FETCHARGS]
 360  *
 361  *  - Remove uprobe: -:[GRP/]EVENT
 362  */
 363 static int create_trace_uprobe(int argc, char **argv)
 364 {
 365         struct trace_uprobe *tu;
 366         struct inode *inode;
 367         char *arg, *event, *group, *filename;
 368         char buf[MAX_EVENT_NAME_LEN];
 369         struct path path;
 370         unsigned long offset;
 371         bool is_delete, is_return;
 372         int i, ret;
 373
 374         inode = NULL;
 375         ret = 0;
 376         is_delete = false;
 377         is_return = false;
 378         event = NULL;
 379         group = NULL;
 380
 381         /* argc must be >= 1 */
 382         if (argv[0][0] == '-')
 383                 is_delete = true;
 384         else if (argv[0][0] == 'r')
 385                 is_return = true;
 386         else if (argv[0][0] != 'p') {
 387                 pr_info("Probe definition must be started with 'p', 'r' or '-'.\n");
 388                 return -EINVAL;
 389         }
 390
 391         if (argv[0][1] == ':') {
 392                 event = &argv[0][2];
 393                 arg = strchr(event, '/');
 394
 395                 if (arg) {
 396                         group = event;
 397                         event = arg + 1;
 398                         event[-1] = '\0';
 399
 400                         if (strlen(group) == 0) {
 401                                 pr_info("Group name is not specified\n");
 402                                 return -EINVAL;
 403                         }
 404                 }
 405                 if (strlen(event) == 0) {
 406                         pr_info("Event name is not specified\n");
 407                         return -EINVAL;
 408                 }
 409         }
 410         if (!group)
 411                 group = UPROBE_EVENT_SYSTEM;
 412
 413         if (is_delete) {
 414                 int ret;
 415
 416                 if (!event) {
 417                         pr_info("Delete command needs an event name.\n");
 418                         return -EINVAL;
 419                 }
 420                 mutex_lock(&uprobe_lock);
 421                 tu = find_probe_event(event, group);
 422
 423                 if (!tu) {
 424                         mutex_unlock(&uprobe_lock);
 425                         pr_info("Event %s/%s doesn't exist.\n", group, event);
 426                         return -ENOENT;
 427                 }
 428                 /* delete an event */
 429                 ret = unregister_trace_uprobe(tu);
 430                 mutex_unlock(&uprobe_lock);
 431                 return ret;
 432         }
 433
 434         if (argc < 2) {
 435                 pr_info("Probe point is not specified.\n");
 436                 return -EINVAL;
 437         }
 438         /* Find the last occurrence, in case the path contains ':' too. */
 439         arg = strrchr(argv[1], ':');
 440         if (!arg) {
 441                 ret = -EINVAL;
 442                 goto fail_address_parse;
 443         }
 444
 445         *arg++ = '\0';
 446         filename = argv[1];
 447         ret = kern_path(filename, LOOKUP_FOLLOW, &path);
 448         if (ret)
 449                 goto fail_address_parse;
 450
 451         inode = igrab(d_real_inode(path.dentry));
 452         path_put(&path);
 453
 454         if (!inode || !S_ISREG(inode->i_mode)) {
 455                 ret = -EINVAL;
 456                 goto fail_address_parse;
 457         }
 458
 459         ret = kstrtoul(arg, 0, &offset);
 460         if (ret)
 461                 goto fail_address_parse;
 462
 463         argc -= 2;
 464         argv += 2;
 465
 466         /* setup a probe */
 467         if (!event) {
 468                 char *tail;
 469                 char *ptr;
 470
 471                 tail = kstrdup(kbasename(filename), GFP_KERNEL);
 472                 if (!tail) {
 473                         ret = -ENOMEM;
 474                         goto fail_address_parse;
 475                 }
 476
 477                 ptr = strpbrk(tail, ".-_");
 478                 if (ptr)
 479                         *ptr = '\0';
 480
 481                 snprintf(buf, MAX_EVENT_NAME_LEN, "%c_%s_0x%lx", 'p', tail, offset);
 482                 event = buf;
 483                 kfree(tail);
 484         }
 485
 486         tu = alloc_trace_uprobe(group, event, argc, is_return);
 487         if (IS_ERR(tu)) {
 488                 pr_info("Failed to allocate trace_uprobe.(%d)\n", (int)PTR_ERR(tu));
 489                 ret = PTR_ERR(tu);
 490                 goto fail_address_parse;
 491         }
 492         tu->offset = offset;
 493         tu->inode = inode;
 494         tu->filename = kstrdup(filename, GFP_KERNEL);
 495
 496         if (!tu->filename) {
 497                 pr_info("Failed to allocate filename.\n");
 498                 ret = -ENOMEM;
 499                 goto error;
 500         }
 501
 502         /* parse arguments */
 503         ret = 0;
 504         for (i = 0; i < argc && i < MAX_TRACE_ARGS; i++) {
 505                 struct probe_arg *parg = &tu->tp.args[i];
 506
 507                 /* Increment count for freeing args in error case */
 508                 tu->tp.nr_args++;
 509
 510                 /* Parse argument name */
 511                 arg = strchr(argv[i], '=');
 512                 if (arg) {
 513                         *arg++ = '\0';
 514                         parg->name = kstrdup(argv[i], GFP_KERNEL);
 515                 } else {
 516                         arg = argv[i];
 517                         /* If argument name is omitted, set "argN" */
 518                         snprintf(buf, MAX_EVENT_NAME_LEN, "arg%d", i + 1);
 519                         parg->name = kstrdup(buf, GFP_KERNEL);
 520                 }
 521
 522                 if (!parg->name) {
 523                         pr_info("Failed to allocate argument[%d] name.\n", i);
 524                         ret = -ENOMEM;
 525                         goto error;
 526                 }
 527
 528                 if (!is_good_name(parg->name)) {
 529                         pr_info("Invalid argument[%d] name: %s\n", i, parg->name);
 530                         ret = -EINVAL;
 531                         goto error;
 532                 }
 533
 534                 if (traceprobe_conflict_field_name(parg->name, tu->tp.args, i)) {
 535                         pr_info("Argument[%d] name '%s' conflicts with "
 536                                 "another field.\n", i, argv[i]);
 537                         ret = -EINVAL;
 538                         goto error;
 539                 }
 540
 541                 /* Parse fetch argument */
 542                 ret = traceprobe_parse_probe_arg(arg, &tu->tp.size, parg,
 543                                                  is_return, false,
 544                                                  uprobes_fetch_type_table);
 545                 if (ret) {
 546                         pr_info("Parse error at argument[%d]. (%d)\n", i, ret);
 547                         goto error;
 548                 }
 549         }
 550
 551         ret = register_trace_uprobe(tu);
 552         if (ret)
 553                 goto error;
 554         return 0;
 555
 556 error:
 557         free_trace_uprobe(tu);
 558         return ret;
 559
 560 fail_address_parse:
 561         iput(inode);
 562
 563         pr_info("Failed to parse address or file.\n");
 564
 565         return ret;
 566 }
 567
 568 static int cleanup_all_probes(void)
 569 {
 570         struct trace_uprobe *tu;
 571         int ret = 0;
 572
 573         mutex_lock(&uprobe_lock);
 574         while (!list_empty(&uprobe_list)) {
 575                 tu = list_entry(uprobe_list.next, struct trace_uprobe, list);
 576                 ret = unregister_trace_uprobe(tu);
 577                 if (ret)
 578                         break;
 579         }
 580         mutex_unlock(&uprobe_lock);
 581         return ret;
 582 }
 583
 584 /* Probes listing interfaces */
 585 static void *probes_seq_start(struct seq_file *m, loff_t *pos)
 586 {
 587         mutex_lock(&uprobe_lock);
 588         return seq_list_start(&uprobe_list, *pos);
 589 }
 590
 591 static void *probes_seq_next(struct seq_file *m, void *v, loff_t *pos)
 592 {
 593         return seq_list_next(v, &uprobe_list, pos);
 594 }
 595
 596 static void probes_seq_stop(struct seq_file *m, void *v)
 597 {
 598         mutex_unlock(&uprobe_lock);
 599 }
 600
 601 static int probes_seq_show(struct seq_file *m, void *v)
 602 {
 603         struct trace_uprobe *tu = v;
 604         char c = is_ret_probe(tu) ? 'r' : 'p';
 605         int i;
 606
 607         seq_printf(m, "%c:%s/%s %s:0x%0*lx", c, tu->tp.call.class->system,
 608                         trace_event_name(&tu->tp.call), tu->filename,
 609                         (int)(sizeof(void *) * 2), tu->offset);
 610
 611         for (i = 0; i < tu->tp.nr_args; i++)
 612                 seq_printf(m, " %s=%s", tu->tp.args[i].name, tu->tp.args[i].comm);
 613
 614         seq_putc(m, '\n');
 615         return 0;
 616 }
 617
 618 static const struct seq_operations probes_seq_op = {
 619         .start  = probes_seq_start,
 620         .next   = probes_seq_next,
 621         .stop   = probes_seq_stop,
 622         .show   = probes_seq_show
 623 };
 624
 625 static int probes_open(struct inode *inode, struct file *file)
 626 {
 627         int ret;
 628
 629         if ((file->f_mode & FMODE_WRITE) && (file->f_flags & O_TRUNC)) {
 630                 ret = cleanup_all_probes();
 631                 if (ret)
 632                         return ret;
 633         }
 634
 635         return seq_open(file, &probes_seq_op);
 636 }
 637
 638 static ssize_t probes_write(struct file *file, const char __user *buffer,
 639                             size_t count, loff_t *ppos)
 640 {
 641         return trace_parse_run_command(file, buffer, count, ppos, create_trace_uprobe);
 642 }
 643
 644 static const struct file_operations uprobe_events_ops = {
 645         .owner          = THIS_MODULE,
 646         .open           = probes_open,
 647         .read           = seq_read,
 648         .llseek         = seq_lseek,
 649         .release        = seq_release,
 650         .write          = probes_write,
 651 };
 652
 653 /* Probes profiling interfaces */
 654 static int probes_profile_seq_show(struct seq_file *m, void *v)
 655 {
 656         struct trace_uprobe *tu = v;
 657
 658         seq_printf(m, "  %s %-44s %15lu\n", tu->filename,
 659                         trace_event_name(&tu->tp.call), tu->nhit);
 660         return 0;
 661 }
 662
 663 static const struct seq_operations profile_seq_op = {
 664         .start  = probes_seq_start,
 665         .next   = probes_seq_next,
 666         .stop   = probes_seq_stop,
 667         .show   = probes_profile_seq_show
 668 };
 669
 670 static int profile_open(struct inode *inode, struct file *file)
 671 {
 672         return seq_open(file, &profile_seq_op);
 673 }
 674
 675 static const struct file_operations uprobe_profile_ops = {
 676         .owner          = THIS_MODULE,
 677         .open           = profile_open,
 678         .read           = seq_read,
 679         .llseek         = seq_lseek,
 680         .release        = seq_release,
 681 };
 682
 683 struct uprobe_cpu_buffer {
 684         struct mutex mutex;
 685         void *buf;
 686 };
 687 static struct uprobe_cpu_buffer __percpu *uprobe_cpu_buffer;
 688 static int uprobe_buffer_refcnt;
 689
 690 static int uprobe_buffer_init(void)
 691 {
 692         int cpu, err_cpu;
 693
 694         uprobe_cpu_buffer = alloc_percpu(struct uprobe_cpu_buffer);
 695         if (uprobe_cpu_buffer == NULL)
 696                 return -ENOMEM;
 697
 698         for_each_possible_cpu(cpu) {
 699                 struct page *p = alloc_pages_node(cpu_to_node(cpu),
 700                                                   GFP_KERNEL, 0);
 701                 if (p == NULL) {
 702                         err_cpu = cpu;
 703                         goto err;
 704                 }
 705                 per_cpu_ptr(uprobe_cpu_buffer, cpu)->buf = page_address(p);
 706                 mutex_init(&per_cpu_ptr(uprobe_cpu_buffer, cpu)->mutex);
 707         }
 708
 709         return 0;
 710
 711 err:
 712         for_each_possible_cpu(cpu) {
 713                 if (cpu == err_cpu)
 714                         break;
 715                 free_page((unsigned long)per_cpu_ptr(uprobe_cpu_buffer, cpu)->buf);
 716         }
 717
 718         free_percpu(uprobe_cpu_buffer);
 719         return -ENOMEM;
 720 }
 721
 722 static int uprobe_buffer_enable(void)
 723 {
 724         int ret = 0;
 725
 726         BUG_ON(!mutex_is_locked(&event_mutex));
 727
 728         if (uprobe_buffer_refcnt++ == 0) {
 729                 ret = uprobe_buffer_init();
 730                 if (ret < 0)
 731                         uprobe_buffer_refcnt--;
 732         }
 733
 734         return ret;
 735 }
 736
 737 static void uprobe_buffer_disable(void)
 738 {
 739         int cpu;
 740
 741         BUG_ON(!mutex_is_locked(&event_mutex));
 742
 743         if (--uprobe_buffer_refcnt == 0) {
 744                 for_each_possible_cpu(cpu)
 745                         free_page((unsigned long)per_cpu_ptr(uprobe_cpu_buffer,
 746                                                              cpu)->buf);
 747
 748                 free_percpu(uprobe_cpu_buffer);
 749                 uprobe_cpu_buffer = NULL;
 750         }
 751 }
 752
 753 static struct uprobe_cpu_buffer *uprobe_buffer_get(void)
 754 {
 755         struct uprobe_cpu_buffer *ucb;
 756         int cpu;
 757
 758         cpu = raw_smp_processor_id();
 759         ucb = per_cpu_ptr(uprobe_cpu_buffer, cpu);
 760
 761         /*
 762          * Use per-cpu buffers for fastest access, but we might migrate
 763          * so the mutex makes sure we have sole access to it.
 764          */
 765         mutex_lock(&ucb->mutex);
 766
 767         return ucb;
 768 }
 769
 770 static void uprobe_buffer_put(struct uprobe_cpu_buffer *ucb)
 771 {
 772         mutex_unlock(&ucb->mutex);
 773 }
 774
 775 static void __uprobe_trace_func(struct trace_uprobe *tu,
 776                                 unsigned long func, struct pt_regs *regs,
 777                                 struct uprobe_cpu_buffer *ucb, int dsize,
 778                                 struct trace_event_file *trace_file)
 779 {
 780         struct uprobe_trace_entry_head *entry;
 781         struct ring_buffer_event *event;
 782         struct ring_buffer *buffer;
 783         void *data;
 784         int size, esize;
 785         struct trace_event_call *call = &tu->tp.call;
 786
 787         WARN_ON(call != trace_file->event_call);
 788
 789         if (WARN_ON_ONCE(tu->tp.size + dsize > PAGE_SIZE))
 790                 return;
 791
 792         if (trace_trigger_soft_disabled(trace_file))
 793                 return;
 794
 795         esize = SIZEOF_TRACE_ENTRY(is_ret_probe(tu));
 796         size = esize + tu->tp.size + dsize;
 797         event = trace_event_buffer_lock_reserve(&buffer, trace_file,
 798                                                 call->event.type, size, 0, 0);
 799         if (!event)
 800                 return;
 801
 802         entry = ring_buffer_event_data(event);
 803         if (is_ret_probe(tu)) {
 804                 entry->vaddr[0] = func;
 805                 entry->vaddr[1] = instruction_pointer(regs);
 806                 data = DATAOF_TRACE_ENTRY(entry, true);
 807         } else {
 808                 entry->vaddr[0] = instruction_pointer(regs);
 809                 data = DATAOF_TRACE_ENTRY(entry, false);
 810         }
 811
 812         memcpy(data, ucb->buf, tu->tp.size + dsize);
 813
 814         event_trigger_unlock_commit(trace_file, buffer, event, entry, 0, 0);
 815 }
 816
 817 /* uprobe handler */
 818 static int uprobe_trace_func(struct trace_uprobe *tu, struct pt_regs *regs,
 819                              struct uprobe_cpu_buffer *ucb, int dsize)
 820 {
 821         struct event_file_link *link;
 822
 823         if (is_ret_probe(tu))
 824                 return 0;
 825
 826         rcu_read_lock();
 827         list_for_each_entry_rcu(link, &tu->tp.files, list)
 828                 __uprobe_trace_func(tu, 0, regs, ucb, dsize, link->file);
 829         rcu_read_unlock();
 830
 831         return 0;
 832 }
 833
 834 static void uretprobe_trace_func(struct trace_uprobe *tu, unsigned long func,
 835                                  struct pt_regs *regs,
 836                                  struct uprobe_cpu_buffer *ucb, int dsize)
 837 {
 838         struct event_file_link *link;
 839
 840         rcu_read_lock();
 841         list_for_each_entry_rcu(link, &tu->tp.files, list)
 842                 __uprobe_trace_func(tu, func, regs, ucb, dsize, link->file);
 843         rcu_read_unlock();
 844 }
 845
 846 /* Event entry printers */
 847 static enum print_line_t
 848 print_uprobe_event(struct trace_iterator *iter, int flags, struct trace_event *event)
 849 {
 850         struct uprobe_trace_entry_head *entry;
 851         struct trace_seq *s = &iter->seq;
 852         struct trace_uprobe *tu;
 853         u8 *data;
 854         int i;
 855
 856         entry = (struct uprobe_trace_entry_head *)iter->ent;
 857         tu = container_of(event, struct trace_uprobe, tp.call.event);
 858
 859         if (is_ret_probe(tu)) {
 860                 trace_seq_printf(s, "%s: (0x%lx <- 0x%lx)",
 861                                  trace_event_name(&tu->tp.call),
 862                                  entry->vaddr[1], entry->vaddr[0]);
 863                 data = DATAOF_TRACE_ENTRY(entry, true);
 864         } else {
 865                 trace_seq_printf(s, "%s: (0x%lx)",
 866                                  trace_event_name(&tu->tp.call),
 867                                  entry->vaddr[0]);
 868                 data = DATAOF_TRACE_ENTRY(entry, false);
 869         }
 870
 871         for (i = 0; i < tu->tp.nr_args; i++) {
 872                 struct probe_arg *parg = &tu->tp.args[i];
 873
 874                 if (!parg->type->print(s, parg->name, data + parg->offset, entry))
 875                         goto out;
 876         }
 877
 878         trace_seq_putc(s, '\n');
 879
 880  out:
 881         return trace_handle_return(s);
 882 }
 883
 884 typedef bool (*filter_func_t)(struct uprobe_consumer *self,
 885                                 enum uprobe_filter_ctx ctx,
 886                                 struct mm_struct *mm);
 887
 888 static int
 889 probe_event_enable(struct trace_uprobe *tu, struct trace_event_file *file,
 890                    filter_func_t filter)
 891 {
 892         bool enabled = trace_probe_is_enabled(&tu->tp);
 893         struct event_file_link *link = NULL;
 894         int ret;
 895
 896         if (file) {
 897                 if (tu->tp.flags & TP_FLAG_PROFILE)
 898                         return -EINTR;
 899
 900                 link = kmalloc(sizeof(*link), GFP_KERNEL);
 901                 if (!link)
 902                         return -ENOMEM;
 903
 904                 link->file = file;
 905                 list_add_tail_rcu(&link->list, &tu->tp.files);
 906
 907                 tu->tp.flags |= TP_FLAG_TRACE;
 908         } else {
 909                 if (tu->tp.flags & TP_FLAG_TRACE)
 910                         return -EINTR;
 911
 912                 tu->tp.flags |= TP_FLAG_PROFILE;
 913         }
 914
 915         WARN_ON(!uprobe_filter_is_empty(&tu->filter));
 916
 917         if (enabled)
 918                 return 0;
 919
 920         ret = uprobe_buffer_enable();
 921         if (ret)
 922                 goto err_flags;
 923
 924         tu->consumer.filter = filter;
 925         ret = uprobe_register(tu->inode, tu->offset, &tu->consumer);
 926         if (ret)
 927                 goto err_buffer;
 928
 929         return 0;
 930
 931  err_buffer:
 932         uprobe_buffer_disable();
 933
 934  err_flags:
 935         if (file) {
 936                 list_del(&link->list);
 937                 kfree(link);
 938                 tu->tp.flags &= ~TP_FLAG_TRACE;
 939         } else {
 940                 tu->tp.flags &= ~TP_FLAG_PROFILE;
 941         }
 942         return ret;
 943 }
 944
 945 static void
 946 probe_event_disable(struct trace_uprobe *tu, struct trace_event_file *file)
 947 {
 948         if (!trace_probe_is_enabled(&tu->tp))
 949                 return;
 950
 951         if (file) {
 952                 struct event_file_link *link;
 953
 954                 link = find_event_file_link(&tu->tp, file);
 955                 if (!link)
 956                         return;
 957
 958                 list_del_rcu(&link->list);
 959                 /* synchronize with u{,ret}probe_trace_func */
 960                 synchronize_sched();
 961                 kfree(link);
 962
 963                 if (!list_empty(&tu->tp.files))
 964                         return;
 965         }
 966
 967         WARN_ON(!uprobe_filter_is_empty(&tu->filter));
 968
 969         uprobe_unregister(tu->inode, tu->offset, &tu->consumer);
 970         tu->tp.flags &= file ? ~TP_FLAG_TRACE : ~TP_FLAG_PROFILE;
 971
 972         uprobe_buffer_disable();
 973 }
 974
 975 static int uprobe_event_define_fields(struct trace_event_call *event_call)
 976 {
 977         int ret, i, size;
 978         struct uprobe_trace_entry_head field;
 979         struct trace_uprobe *tu = event_call->data;
 980
 981         if (is_ret_probe(tu)) {
 982                 DEFINE_FIELD(unsigned long, vaddr[0], FIELD_STRING_FUNC, 0);
 983                 DEFINE_FIELD(unsigned long, vaddr[1], FIELD_STRING_RETIP, 0);
 984                 size = SIZEOF_TRACE_ENTRY(true);
 985         } else {
 986                 DEFINE_FIELD(unsigned long, vaddr[0], FIELD_STRING_IP, 0);
 987                 size = SIZEOF_TRACE_ENTRY(false);
 988         }
 989         /* Set argument names as fields */
 990         for (i = 0; i < tu->tp.nr_args; i++) {
 991                 struct probe_arg *parg = &tu->tp.args[i];
 992
 993                 ret = trace_define_field(event_call, parg->type->fmttype,
 994                                          parg->name, size + parg->offset,
 995                                          parg->type->size, parg->type->is_signed,
 996                                          FILTER_OTHER);
 997
 998                 if (ret)
 999                         return ret;
1000         }
1001         return 0;
1002 }
1003
1004 #ifdef CONFIG_PERF_EVENTS
1005 static bool
1006 __uprobe_perf_filter(struct trace_uprobe_filter *filter, struct mm_struct *mm)
1007 {
1008         struct perf_event *event;
1009
1010         if (filter->nr_systemwide)
1011                 return true;
1012
1013         list_for_each_entry(event, &filter->perf_events, hw.tp_list) {
1014                 if (event->hw.target->mm == mm)
1015                         return true;
1016         }
1017
1018         return false;
1019 }
1020
1021 static inline bool
1022 uprobe_filter_event(struct trace_uprobe *tu, struct perf_event *event)
1023 {
1024         return __uprobe_perf_filter(&tu->filter, event->hw.target->mm);
1025 }
1026
1027 static int uprobe_perf_close(struct trace_uprobe *tu, struct perf_event *event)
1028 {
1029         bool done;
1030
1031         write_lock(&tu->filter.rwlock);
1032         if (event->hw.target) {
1033                 list_del(&event->hw.tp_list);
1034                 done = tu->filter.nr_systemwide ||
1035                         (event->hw.target->flags & PF_EXITING) ||
1036                         uprobe_filter_event(tu, event);
1037         } else {
1038                 tu->filter.nr_systemwide--;
1039                 done = tu->filter.nr_systemwide;
1040         }
1041         write_unlock(&tu->filter.rwlock);
1042
1043         if (!done)
1044                 return uprobe_apply(tu->inode, tu->offset, &tu->consumer, false);
1045
1046         return 0;
1047 }
1048
1049 static int uprobe_perf_open(struct trace_uprobe *tu, struct perf_event *event)
1050 {
1051         bool done;
1052         int err;
1053
1054         write_lock(&tu->filter.rwlock);
1055         if (event->hw.target) {
1056                 /*
1057                  * event->parent != NULL means copy_process(), we can avoid
1058                  * uprobe_apply(). current->mm must be probed and we can rely
1059                  * on dup_mmap() which preserves the already installed bp's.
1060                  *
1061                  * attr.enable_on_exec means that exec/mmap will install the
1062                  * breakpoints we need.
1063                  */
1064                 done = tu->filter.nr_systemwide ||
1065                         event->parent || event->attr.enable_on_exec ||
1066                         uprobe_filter_event(tu, event);
1067                 list_add(&event->hw.tp_list, &tu->filter.perf_events);
1068         } else {
1069                 done = tu->filter.nr_systemwide;
1070                 tu->filter.nr_systemwide++;
1071         }
1072         write_unlock(&tu->filter.rwlock);
1073
1074         err = 0;
1075         if (!done) {
1076                 err = uprobe_apply(tu->inode, tu->offset, &tu->consumer, true);
1077                 if (err)
1078                         uprobe_perf_close(tu, event);
1079         }
1080         return err;
1081 }
1082
1083 static bool uprobe_perf_filter(struct uprobe_consumer *uc,
1084                                 enum uprobe_filter_ctx ctx, struct mm_struct *mm)
1085 {
1086         struct trace_uprobe *tu;
1087         int ret;
1088
1089         tu = container_of(uc, struct trace_uprobe, consumer);
1090         read_lock(&tu->filter.rwlock);
1091         ret = __uprobe_perf_filter(&tu->filter, mm);
1092         read_unlock(&tu->filter.rwlock);
1093
1094         return ret;
1095 }
1096
1097 static void __uprobe_perf_func(struct trace_uprobe *tu,
1098                                unsigned long func, struct pt_regs *regs,
1099                                struct uprobe_cpu_buffer *ucb, int dsize)
1100 {
1101         struct trace_event_call *call = &tu->tp.call;
1102         struct uprobe_trace_entry_head *entry;
1103         struct hlist_head *head;
1104         void *data;
1105         int size, esize;
1106         int rctx;
1107
1108         if (bpf_prog_array_valid(call) && !trace_call_bpf(call, regs))
1109                 return;
1110
1111         esize = SIZEOF_TRACE_ENTRY(is_ret_probe(tu));
1112
1113         size = esize + tu->tp.size + dsize;
1114         size = ALIGN(size + sizeof(u32), sizeof(u64)) - sizeof(u32);
1115         if (WARN_ONCE(size > PERF_MAX_TRACE_SIZE, "profile buffer not large enough"))
1116                 return;
1117
1118         preempt_disable();
1119         head = this_cpu_ptr(call->perf_events);
1120         if (hlist_empty(head))
1121                 goto out;
1122
1123         entry = perf_trace_buf_alloc(size, NULL, &rctx);
1124         if (!entry)
1125                 goto out;
1126
1127         if (is_ret_probe(tu)) {
1128                 entry->vaddr[0] = func;
1129                 entry->vaddr[1] = instruction_pointer(regs);
1130                 data = DATAOF_TRACE_ENTRY(entry, true);
1131         } else {
1132                 entry->vaddr[0] = instruction_pointer(regs);
1133                 data = DATAOF_TRACE_ENTRY(entry, false);
1134         }
1135
1136         memcpy(data, ucb->buf, tu->tp.size + dsize);
1137
1138         if (size - esize > tu->tp.size + dsize) {
1139                 int len = tu->tp.size + dsize;
1140
1141                 memset(data + len, 0, size - esize - len);
1142         }
1143
1144         perf_trace_buf_submit(entry, size, rctx, call->event.type, 1, regs,
1145                               head, NULL);
1146  out:
1147         preempt_enable();
1148 }
1149
1150 /* uprobe profile handler */
1151 static int uprobe_perf_func(struct trace_uprobe *tu, struct pt_regs *regs,
1152                             struct uprobe_cpu_buffer *ucb, int dsize)
1153 {
1154         if (!uprobe_perf_filter(&tu->consumer, 0, current->mm))
1155                 return UPROBE_HANDLER_REMOVE;
1156
1157         if (!is_ret_probe(tu))
1158                 __uprobe_perf_func(tu, 0, regs, ucb, dsize);
1159         return 0;
1160 }
1161
1162 static void uretprobe_perf_func(struct trace_uprobe *tu, unsigned long func,
1163                                 struct pt_regs *regs,
1164                                 struct uprobe_cpu_buffer *ucb, int dsize)
1165 {
1166         __uprobe_perf_func(tu, func, regs, ucb, dsize);
1167 }
1168 #endif  /* CONFIG_PERF_EVENTS */
1169
1170 static int
1171 trace_uprobe_register(struct trace_event_call *event, enum trace_reg type,
1172                       void *data)
1173 {
1174         struct trace_uprobe *tu = event->data;
1175         struct trace_event_file *file = data;
1176
1177         switch (type) {
1178         case TRACE_REG_REGISTER:
1179                 return probe_event_enable(tu, file, NULL);
1180
1181         case TRACE_REG_UNREGISTER:
1182                 probe_event_disable(tu, file);
1183                 return 0;
1184
1185 #ifdef CONFIG_PERF_EVENTS
1186         case TRACE_REG_PERF_REGISTER:
1187                 return probe_event_enable(tu, NULL, uprobe_perf_filter);
1188
1189         case TRACE_REG_PERF_UNREGISTER:
1190                 probe_event_disable(tu, NULL);
1191                 return 0;
1192
1193         case TRACE_REG_PERF_OPEN:
1194                 return uprobe_perf_open(tu, data);
1195
1196         case TRACE_REG_PERF_CLOSE:
1197                 return uprobe_perf_close(tu, data);
1198
1199 #endif
1200         default:
1201                 return 0;
1202         }
1203         return 0;
1204 }
1205
1206 static int uprobe_dispatcher(struct uprobe_consumer *con, struct pt_regs *regs)
1207 {
1208         struct trace_uprobe *tu;
1209         struct uprobe_dispatch_data udd;
1210         struct uprobe_cpu_buffer *ucb;
1211         int dsize, esize;
1212         int ret = 0;
1213
1214
1215         tu = container_of(con, struct trace_uprobe, consumer);
1216         tu->nhit++;
1217
1218         udd.tu = tu;
1219         udd.bp_addr = instruction_pointer(regs);
1220
1221         current->utask->vaddr = (unsigned long) &udd;
1222
1223         if (WARN_ON_ONCE(!uprobe_cpu_buffer))
1224                 return 0;
1225
1226         dsize = __get_data_size(&tu->tp, regs);
1227         esize = SIZEOF_TRACE_ENTRY(is_ret_probe(tu));
1228
1229         ucb = uprobe_buffer_get();
1230         store_trace_args(esize, &tu->tp, regs, ucb->buf, dsize);
1231
1232         if (tu->tp.flags & TP_FLAG_TRACE)
1233                 ret |= uprobe_trace_func(tu, regs, ucb, dsize);
1234
1235 #ifdef CONFIG_PERF_EVENTS
1236         if (tu->tp.flags & TP_FLAG_PROFILE)
1237                 ret |= uprobe_perf_func(tu, regs, ucb, dsize);
1238 #endif
1239         uprobe_buffer_put(ucb);
1240         return ret;
1241 }
1242
1243 static int uretprobe_dispatcher(struct uprobe_consumer *con,
1244                                 unsigned long func, struct pt_regs *regs)
1245 {
1246         struct trace_uprobe *tu;
1247         struct uprobe_dispatch_data udd;
1248         struct uprobe_cpu_buffer *ucb;
1249         int dsize, esize;
1250
1251         tu = container_of(con, struct trace_uprobe, consumer);
1252
1253         udd.tu = tu;
1254         udd.bp_addr = func;
1255
1256         current->utask->vaddr = (unsigned long) &udd;
1257
1258         if (WARN_ON_ONCE(!uprobe_cpu_buffer))
1259                 return 0;
1260
1261         dsize = __get_data_size(&tu->tp, regs);
1262         esize = SIZEOF_TRACE_ENTRY(is_ret_probe(tu));
1263
1264         ucb = uprobe_buffer_get();
1265         store_trace_args(esize, &tu->tp, regs, ucb->buf, dsize);
1266
1267         if (tu->tp.flags & TP_FLAG_TRACE)
1268                 uretprobe_trace_func(tu, func, regs, ucb, dsize);
1269
1270 #ifdef CONFIG_PERF_EVENTS
1271         if (tu->tp.flags & TP_FLAG_PROFILE)
1272                 uretprobe_perf_func(tu, func, regs, ucb, dsize);
1273 #endif
1274         uprobe_buffer_put(ucb);
1275         return 0;
1276 }
1277
1278 static struct trace_event_functions uprobe_funcs = {
1279         .trace          = print_uprobe_event
1280 };
1281
1282 static inline void init_trace_event_call(struct trace_uprobe *tu,
1283                                          struct trace_event_call *call)
1284 {
1285         INIT_LIST_HEAD(&call->class->fields);
1286         call->event.funcs = &uprobe_funcs;
1287         call->class->define_fields = uprobe_event_define_fields;
1288
1289         call->flags = TRACE_EVENT_FL_UPROBE;
1290         call->class->reg = trace_uprobe_register;
1291         call->data = tu;
1292 }
1293
1294 static int register_uprobe_event(struct trace_uprobe *tu)
1295 {
1296         struct trace_event_call *call = &tu->tp.call;
1297         int ret = 0;
1298
1299         init_trace_event_call(tu, call);
1300
1301         if (set_print_fmt(&tu->tp, is_ret_probe(tu)) < 0)
1302                 return -ENOMEM;
1303
1304         ret = register_trace_event(&call->event);
1305         if (!ret) {
1306                 kfree(call->print_fmt);
1307                 return -ENODEV;
1308         }
1309
1310         ret = trace_add_event_call(call);
1311
1312         if (ret) {
1313                 pr_info("Failed to register uprobe event: %s\n",
1314                         trace_event_name(call));
1315                 kfree(call->print_fmt);
1316                 unregister_trace_event(&call->event);
1317         }
1318
1319         return ret;
1320 }
1321
1322 static int unregister_uprobe_event(struct trace_uprobe *tu)
1323 {
1324         int ret;
1325
1326         /* tu->event is unregistered in trace_remove_event_call() */
1327         ret = trace_remove_event_call(&tu->tp.call);
1328         if (ret)
1329                 return ret;
1330         kfree(tu->tp.call.print_fmt);
1331         tu->tp.call.print_fmt = NULL;
1332         return 0;
1333 }
1334
1335 #ifdef CONFIG_PERF_EVENTS
1336 struct trace_event_call *
1337 create_local_trace_uprobe(char *name, unsigned long offs, bool is_return)
1338 {
1339         struct trace_uprobe *tu;
1340         struct inode *inode;
1341         struct path path;
1342         int ret;
1343
1344         ret = kern_path(name, LOOKUP_FOLLOW, &path);
1345         if (ret)
1346                 return ERR_PTR(ret);
1347
1348         inode = igrab(d_inode(path.dentry));
1349         path_put(&path);
1350
1351         if (!inode || !S_ISREG(inode->i_mode)) {
1352                 iput(inode);
1353                 return ERR_PTR(-EINVAL);
1354         }
1355
1356         /*
1357          * local trace_kprobes are not added to probe_list, so they are never
1358          * searched in find_trace_kprobe(). Therefore, there is no concern of
1359          * duplicated name "DUMMY_EVENT" here.
1360          */
1361         tu = alloc_trace_uprobe(UPROBE_EVENT_SYSTEM, "DUMMY_EVENT", 0,
1362                                 is_return);
1363
1364         if (IS_ERR(tu)) {
1365                 pr_info("Failed to allocate trace_uprobe.(%d)\n",
1366                         (int)PTR_ERR(tu));
1367                 return ERR_CAST(tu);
1368         }
1369
1370         tu->offset = offs;
1371         tu->inode = inode;
1372         tu->filename = kstrdup(name, GFP_KERNEL);
1373         init_trace_event_call(tu, &tu->tp.call);
1374
1375         if (set_print_fmt(&tu->tp, is_ret_probe(tu)) < 0) {
1376                 ret = -ENOMEM;
1377                 goto error;
1378         }
1379
1380         return &tu->tp.call;
1381 error:
1382         free_trace_uprobe(tu);
1383         return ERR_PTR(ret);
1384 }
1385
1386 void destroy_local_trace_uprobe(struct trace_event_call *event_call)
1387 {
1388         struct trace_uprobe *tu;
1389
1390         tu = container_of(event_call, struct trace_uprobe, tp.call);
1391
1392         kfree(tu->tp.call.print_fmt);
1393         tu->tp.call.print_fmt = NULL;
1394
1395         free_trace_uprobe(tu);
1396 }
1397 #endif /* CONFIG_PERF_EVENTS */
1398
1399 /* Make a trace interface for controling probe points */
1400 static __init int init_uprobe_trace(void)
1401 {
1402         struct dentry *d_tracer;
1403
1404         d_tracer = tracing_init_dentry();
1405         if (IS_ERR(d_tracer))
1406                 return 0;
1407
1408         trace_create_file("uprobe_events", 0644, d_tracer,
1409                                     NULL, &uprobe_events_ops);
1410         /* Profile interface */
1411         trace_create_file("uprobe_profile", 0444, d_tracer,
1412                                     NULL, &uprobe_profile_ops);
1413         return 0;
1414 }
1415
1416 fs_initcall(init_uprobe_trace);