kernel/trace/trace_uprobe.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * uprobes-based tracing events
   4  *
   5  * Copyright (C) IBM Corporation, 2010-2012
   6  * Author:      Srikar Dronamraju <srikar@linux.vnet.ibm.com>
   7  */
   8 #define pr_fmt(fmt)     "trace_uprobe: " fmt
   9
  10 #include <linux/module.h>
  11 #include <linux/uaccess.h>
  12 #include <linux/uprobes.h>
  13 #include <linux/namei.h>
  14 #include <linux/string.h>
  15 #include <linux/rculist.h>
  16
  17 #include "trace_probe.h"
  18
  19 #define UPROBE_EVENT_SYSTEM     "uprobes"
  20
  21 struct uprobe_trace_entry_head {
  22         struct trace_entry      ent;
  23         unsigned long           vaddr[];
  24 };
  25
  26 #define SIZEOF_TRACE_ENTRY(is_return)                   \
  27         (sizeof(struct uprobe_trace_entry_head) +       \
  28          sizeof(unsigned long) * (is_return ? 2 : 1))
  29
  30 #define DATAOF_TRACE_ENTRY(entry, is_return)            \
  31         ((void*)(entry) + SIZEOF_TRACE_ENTRY(is_return))
  32
  33 struct trace_uprobe_filter {
  34         rwlock_t                rwlock;
  35         int                     nr_systemwide;
  36         struct list_head        perf_events;
  37 };
  38
  39 /*
  40  * uprobe event core functions
  41  */
  42 struct trace_uprobe {
  43         struct list_head                list;
  44         struct trace_uprobe_filter      filter;
  45         struct uprobe_consumer          consumer;
  46         struct path                     path;
  47         struct inode                    *inode;
  48         char                            *filename;
  49         unsigned long                   offset;
  50         unsigned long                   nhit;
  51         struct trace_probe              tp;
  52 };
  53
  54 #define SIZEOF_TRACE_UPROBE(n)                          \
  55         (offsetof(struct trace_uprobe, tp.args) +       \
  56         (sizeof(struct probe_arg) * (n)))
  57
  58 static int register_uprobe_event(struct trace_uprobe *tu);
  59 static int unregister_uprobe_event(struct trace_uprobe *tu);
  60
  61 static DEFINE_MUTEX(uprobe_lock);
  62 static LIST_HEAD(uprobe_list);
  63
  64 struct uprobe_dispatch_data {
  65         struct trace_uprobe     *tu;
  66         unsigned long           bp_addr;
  67 };
  68
  69 static int uprobe_dispatcher(struct uprobe_consumer *con, struct pt_regs *regs);
  70 static int uretprobe_dispatcher(struct uprobe_consumer *con,
  71                                 unsigned long func, struct pt_regs *regs);
  72
  73 #ifdef CONFIG_STACK_GROWSUP
  74 static unsigned long adjust_stack_addr(unsigned long addr, unsigned int n)
  75 {
  76         return addr - (n * sizeof(long));
  77 }
  78 #else
  79 static unsigned long adjust_stack_addr(unsigned long addr, unsigned int n)
  80 {
  81         return addr + (n * sizeof(long));
  82 }
  83 #endif
  84
  85 static unsigned long get_user_stack_nth(struct pt_regs *regs, unsigned int n)
  86 {
  87         unsigned long ret;
  88         unsigned long addr = user_stack_pointer(regs);
  89
  90         addr = adjust_stack_addr(addr, n);
  91
  92         if (copy_from_user(&ret, (void __force __user *) addr, sizeof(ret)))
  93                 return 0;
  94
  95         return ret;
  96 }
  97
  98 /*
  99  * Uprobes-specific fetch functions
 100  */
 101 #define DEFINE_FETCH_stack(type)                                        \
 102 static void FETCH_FUNC_NAME(stack, type)(struct pt_regs *regs,          \
 103                                          void *offset, void *dest)      \
 104 {                                                                       \
 105         *(type *)dest = (type)get_user_stack_nth(regs,                  \
 106                                               ((unsigned long)offset)); \
 107 }
 108 DEFINE_BASIC_FETCH_FUNCS(stack)
 109 /* No string on the stack entry */
 110 #define fetch_stack_string      NULL
 111 #define fetch_stack_string_size NULL
 112
 113 #define DEFINE_FETCH_memory(type)                                       \
 114 static void FETCH_FUNC_NAME(memory, type)(struct pt_regs *regs,         \
 115                                           void *addr, void *dest)       \
 116 {                                                                       \
 117         type retval;                                                    \
 118         void __user *vaddr = (void __force __user *) addr;              \
 119                                                                         \
 120         if (copy_from_user(&retval, vaddr, sizeof(type)))               \
 121                 *(type *)dest = 0;                                      \
 122         else                                                            \
 123                 *(type *) dest = retval;                                \
 124 }
 125 DEFINE_BASIC_FETCH_FUNCS(memory)
 126 /*
 127  * Fetch a null-terminated string. Caller MUST set *(u32 *)dest with max
 128  * length and relative data location.
 129  */
 130 static void FETCH_FUNC_NAME(memory, string)(struct pt_regs *regs,
 131                                             void *addr, void *dest)
 132 {
 133         long ret;
 134         u32 rloc = *(u32 *)dest;
 135         int maxlen  = get_rloc_len(rloc);
 136         u8 *dst = get_rloc_data(dest);
 137         void __user *src = (void __force __user *) addr;
 138
 139         if (!maxlen)
 140                 return;
 141
 142         ret = strncpy_from_user(dst, src, maxlen);
 143         if (ret == maxlen)
 144                 dst[ret - 1] = '\0';
 145         else if (ret >= 0)
 146                 /*
 147                  * Include the terminating null byte. In this case it
 148                  * was copied by strncpy_from_user but not accounted
 149                  * for in ret.
 150                  */
 151                 ret++;
 152
 153         if (ret < 0) {  /* Failed to fetch string */
 154                 ((u8 *)get_rloc_data(dest))[0] = '\0';
 155                 *(u32 *)dest = make_data_rloc(0, get_rloc_offs(rloc));
 156         } else {
 157                 *(u32 *)dest = make_data_rloc(ret, get_rloc_offs(rloc));
 158         }
 159 }
 160
 161 static void FETCH_FUNC_NAME(memory, string_size)(struct pt_regs *regs,
 162                                                  void *addr, void *dest)
 163 {
 164         int len;
 165         void __user *vaddr = (void __force __user *) addr;
 166
 167         len = strnlen_user(vaddr, MAX_STRING_SIZE);
 168
 169         if (len == 0 || len > MAX_STRING_SIZE)  /* Failed to check length */
 170                 *(u32 *)dest = 0;
 171         else
 172                 *(u32 *)dest = len;
 173 }
 174
 175 static unsigned long translate_user_vaddr(void *file_offset)
 176 {
 177         unsigned long base_addr;
 178         struct uprobe_dispatch_data *udd;
 179
 180         udd = (void *) current->utask->vaddr;
 181
 182         base_addr = udd->bp_addr - udd->tu->offset;
 183         return base_addr + (unsigned long)file_offset;
 184 }
 185
 186 #define DEFINE_FETCH_file_offset(type)                                  \
 187 static void FETCH_FUNC_NAME(file_offset, type)(struct pt_regs *regs,    \
 188                                                void *offset, void *dest)\
 189 {                                                                       \
 190         void *vaddr = (void *)translate_user_vaddr(offset);             \
 191                                                                         \
 192         FETCH_FUNC_NAME(memory, type)(regs, vaddr, dest);               \
 193 }
 194 DEFINE_BASIC_FETCH_FUNCS(file_offset)
 195 DEFINE_FETCH_file_offset(string)
 196 DEFINE_FETCH_file_offset(string_size)
 197
 198 /* Fetch type information table */
 199 static const struct fetch_type uprobes_fetch_type_table[] = {
 200         /* Special types */
 201         [FETCH_TYPE_STRING] = __ASSIGN_FETCH_TYPE("string", string, string,
 202                                         sizeof(u32), 1, "__data_loc char[]"),
 203         [FETCH_TYPE_STRSIZE] = __ASSIGN_FETCH_TYPE("string_size", u32,
 204                                         string_size, sizeof(u32), 0, "u32"),
 205         /* Basic types */
 206         ASSIGN_FETCH_TYPE(u8,  u8,  0),
 207         ASSIGN_FETCH_TYPE(u16, u16, 0),
 208         ASSIGN_FETCH_TYPE(u32, u32, 0),
 209         ASSIGN_FETCH_TYPE(u64, u64, 0),
 210         ASSIGN_FETCH_TYPE(s8,  u8,  1),
 211         ASSIGN_FETCH_TYPE(s16, u16, 1),
 212         ASSIGN_FETCH_TYPE(s32, u32, 1),
 213         ASSIGN_FETCH_TYPE(s64, u64, 1),
 214         ASSIGN_FETCH_TYPE_ALIAS(x8,  u8,  u8,  0),
 215         ASSIGN_FETCH_TYPE_ALIAS(x16, u16, u16, 0),
 216         ASSIGN_FETCH_TYPE_ALIAS(x32, u32, u32, 0),
 217         ASSIGN_FETCH_TYPE_ALIAS(x64, u64, u64, 0),
 218
 219         ASSIGN_FETCH_TYPE_END
 220 };
 221
 222 static inline void init_trace_uprobe_filter(struct trace_uprobe_filter *filter)
 223 {
 224         rwlock_init(&filter->rwlock);
 225         filter->nr_systemwide = 0;
 226         INIT_LIST_HEAD(&filter->perf_events);
 227 }
 228
 229 static inline bool uprobe_filter_is_empty(struct trace_uprobe_filter *filter)
 230 {
 231         return !filter->nr_systemwide && list_empty(&filter->perf_events);
 232 }
 233
 234 static inline bool is_ret_probe(struct trace_uprobe *tu)
 235 {
 236         return tu->consumer.ret_handler != NULL;
 237 }
 238
 239 /*
 240  * Allocate new trace_uprobe and initialize it (including uprobes).
 241  */
 242 static struct trace_uprobe *
 243 alloc_trace_uprobe(const char *group, const char *event, int nargs, bool is_ret)
 244 {
 245         struct trace_uprobe *tu;
 246
 247         if (!event || !is_good_name(event))
 248                 return ERR_PTR(-EINVAL);
 249
 250         if (!group || !is_good_name(group))
 251                 return ERR_PTR(-EINVAL);
 252
 253         tu = kzalloc(SIZEOF_TRACE_UPROBE(nargs), GFP_KERNEL);
 254         if (!tu)
 255                 return ERR_PTR(-ENOMEM);
 256
 257         tu->tp.call.class = &tu->tp.class;
 258         tu->tp.call.name = kstrdup(event, GFP_KERNEL);
 259         if (!tu->tp.call.name)
 260                 goto error;
 261
 262         tu->tp.class.system = kstrdup(group, GFP_KERNEL);
 263         if (!tu->tp.class.system)
 264                 goto error;
 265
 266         INIT_LIST_HEAD(&tu->list);
 267         INIT_LIST_HEAD(&tu->tp.files);
 268         tu->consumer.handler = uprobe_dispatcher;
 269         if (is_ret)
 270                 tu->consumer.ret_handler = uretprobe_dispatcher;
 271         init_trace_uprobe_filter(&tu->filter);
 272         return tu;
 273
 274 error:
 275         kfree(tu->tp.call.name);
 276         kfree(tu);
 277
 278         return ERR_PTR(-ENOMEM);
 279 }
 280
 281 static void free_trace_uprobe(struct trace_uprobe *tu)
 282 {
 283         int i;
 284
 285         for (i = 0; i < tu->tp.nr_args; i++)
 286                 traceprobe_free_probe_arg(&tu->tp.args[i]);
 287
 288         path_put(&tu->path);
 289         kfree(tu->tp.call.class->system);
 290         kfree(tu->tp.call.name);
 291         kfree(tu->filename);
 292         kfree(tu);
 293 }
 294
 295 static struct trace_uprobe *find_probe_event(const char *event, const char *group)
 296 {
 297         struct trace_uprobe *tu;
 298
 299         list_for_each_entry(tu, &uprobe_list, list)
 300                 if (strcmp(trace_event_name(&tu->tp.call), event) == 0 &&
 301                     strcmp(tu->tp.call.class->system, group) == 0)
 302                         return tu;
 303
 304         return NULL;
 305 }
 306
 307 /* Unregister a trace_uprobe and probe_event: call with locking uprobe_lock */
 308 static int unregister_trace_uprobe(struct trace_uprobe *tu)
 309 {
 310         int ret;
 311
 312         ret = unregister_uprobe_event(tu);
 313         if (ret)
 314                 return ret;
 315
 316         list_del(&tu->list);
 317         free_trace_uprobe(tu);
 318         return 0;
 319 }
 320
 321 /* Register a trace_uprobe and probe_event */
 322 static int register_trace_uprobe(struct trace_uprobe *tu)
 323 {
 324         struct trace_uprobe *old_tu;
 325         int ret;
 326
 327         mutex_lock(&uprobe_lock);
 328
 329         /* register as an event */
 330         old_tu = find_probe_event(trace_event_name(&tu->tp.call),
 331                         tu->tp.call.class->system);
 332         if (old_tu) {
 333                 /* delete old event */
 334                 ret = unregister_trace_uprobe(old_tu);
 335                 if (ret)
 336                         goto end;
 337         }
 338
 339         ret = register_uprobe_event(tu);
 340         if (ret) {
 341                 pr_warn("Failed to register probe event(%d)\n", ret);
 342                 goto end;
 343         }
 344
 345         list_add_tail(&tu->list, &uprobe_list);
 346
 347 end:
 348         mutex_unlock(&uprobe_lock);
 349
 350         return ret;
 351 }
 352
 353 /*
 354  * Argument syntax:
 355  *  - Add uprobe: p|r[:[GRP/]EVENT] PATH:OFFSET [FETCHARGS]
 356  *
 357  *  - Remove uprobe: -:[GRP/]EVENT
 358  */
 359 static int create_trace_uprobe(int argc, char **argv)
 360 {
 361         struct trace_uprobe *tu;
 362         char *arg, *event, *group, *filename;
 363         char buf[MAX_EVENT_NAME_LEN];
 364         struct path path;
 365         unsigned long offset;
 366         bool is_delete, is_return;
 367         int i, ret;
 368
 369         ret = 0;
 370         is_delete = false;
 371         is_return = false;
 372         event = NULL;
 373         group = NULL;
 374
 375         /* argc must be >= 1 */
 376         if (argv[0][0] == '-')
 377                 is_delete = true;
 378         else if (argv[0][0] == 'r')
 379                 is_return = true;
 380         else if (argv[0][0] != 'p') {
 381                 pr_info("Probe definition must be started with 'p', 'r' or '-'.\n");
 382                 return -EINVAL;
 383         }
 384
 385         if (argv[0][1] == ':') {
 386                 event = &argv[0][2];
 387                 arg = strchr(event, '/');
 388
 389                 if (arg) {
 390                         group = event;
 391                         event = arg + 1;
 392                         event[-1] = '\0';
 393
 394                         if (strlen(group) == 0) {
 395                                 pr_info("Group name is not specified\n");
 396                                 return -EINVAL;
 397                         }
 398                 }
 399                 if (strlen(event) == 0) {
 400                         pr_info("Event name is not specified\n");
 401                         return -EINVAL;
 402                 }
 403         }
 404         if (!group)
 405                 group = UPROBE_EVENT_SYSTEM;
 406
 407         if (is_delete) {
 408                 int ret;
 409
 410                 if (!event) {
 411                         pr_info("Delete command needs an event name.\n");
 412                         return -EINVAL;
 413                 }
 414                 mutex_lock(&uprobe_lock);
 415                 tu = find_probe_event(event, group);
 416
 417                 if (!tu) {
 418                         mutex_unlock(&uprobe_lock);
 419                         pr_info("Event %s/%s doesn't exist.\n", group, event);
 420                         return -ENOENT;
 421                 }
 422                 /* delete an event */
 423                 ret = unregister_trace_uprobe(tu);
 424                 mutex_unlock(&uprobe_lock);
 425                 return ret;
 426         }
 427
 428         if (argc < 2) {
 429                 pr_info("Probe point is not specified.\n");
 430                 return -EINVAL;
 431         }
 432         /* Find the last occurrence, in case the path contains ':' too. */
 433         arg = strrchr(argv[1], ':');
 434         if (!arg)
 435                 return -EINVAL;
 436
 437         *arg++ = '\0';
 438         filename = argv[1];
 439         ret = kern_path(filename, LOOKUP_FOLLOW, &path);
 440         if (ret)
 441                 return ret;
 442
 443         if (!d_is_reg(path.dentry)) {
 444                 ret = -EINVAL;
 445                 goto fail_address_parse;
 446         }
 447
 448         ret = kstrtoul(arg, 0, &offset);
 449         if (ret)
 450                 goto fail_address_parse;
 451
 452         argc -= 2;
 453         argv += 2;
 454
 455         /* setup a probe */
 456         if (!event) {
 457                 char *tail;
 458                 char *ptr;
 459
 460                 tail = kstrdup(kbasename(filename), GFP_KERNEL);
 461                 if (!tail) {
 462                         ret = -ENOMEM;
 463                         goto fail_address_parse;
 464                 }
 465
 466                 ptr = strpbrk(tail, ".-_");
 467                 if (ptr)
 468                         *ptr = '\0';
 469
 470                 snprintf(buf, MAX_EVENT_NAME_LEN, "%c_%s_0x%lx", 'p', tail, offset);
 471                 event = buf;
 472                 kfree(tail);
 473         }
 474
 475         tu = alloc_trace_uprobe(group, event, argc, is_return);
 476         if (IS_ERR(tu)) {
 477                 pr_info("Failed to allocate trace_uprobe.(%d)\n", (int)PTR_ERR(tu));
 478                 ret = PTR_ERR(tu);
 479                 goto fail_address_parse;
 480         }
 481         tu->offset = offset;
 482         tu->path = path;
 483         tu->filename = kstrdup(filename, GFP_KERNEL);
 484
 485         if (!tu->filename) {
 486                 pr_info("Failed to allocate filename.\n");
 487                 ret = -ENOMEM;
 488                 goto error;
 489         }
 490
 491         /* parse arguments */
 492         ret = 0;
 493         for (i = 0; i < argc && i < MAX_TRACE_ARGS; i++) {
 494                 struct probe_arg *parg = &tu->tp.args[i];
 495
 496                 /* Increment count for freeing args in error case */
 497                 tu->tp.nr_args++;
 498
 499                 /* Parse argument name */
 500                 arg = strchr(argv[i], '=');
 501                 if (arg) {
 502                         *arg++ = '\0';
 503                         parg->name = kstrdup(argv[i], GFP_KERNEL);
 504                 } else {
 505                         arg = argv[i];
 506                         /* If argument name is omitted, set "argN" */
 507                         snprintf(buf, MAX_EVENT_NAME_LEN, "arg%d", i + 1);
 508                         parg->name = kstrdup(buf, GFP_KERNEL);
 509                 }
 510
 511                 if (!parg->name) {
 512                         pr_info("Failed to allocate argument[%d] name.\n", i);
 513                         ret = -ENOMEM;
 514                         goto error;
 515                 }
 516
 517                 if (!is_good_name(parg->name)) {
 518                         pr_info("Invalid argument[%d] name: %s\n", i, parg->name);
 519                         ret = -EINVAL;
 520                         goto error;
 521                 }
 522
 523                 if (traceprobe_conflict_field_name(parg->name, tu->tp.args, i)) {
 524                         pr_info("Argument[%d] name '%s' conflicts with "
 525                                 "another field.\n", i, argv[i]);
 526                         ret = -EINVAL;
 527                         goto error;
 528                 }
 529
 530                 /* Parse fetch argument */
 531                 ret = traceprobe_parse_probe_arg(arg, &tu->tp.size, parg,
 532                                                  is_return, false,
 533                                                  uprobes_fetch_type_table);
 534                 if (ret) {
 535                         pr_info("Parse error at argument[%d]. (%d)\n", i, ret);
 536                         goto error;
 537                 }
 538         }
 539
 540         ret = register_trace_uprobe(tu);
 541         if (ret)
 542                 goto error;
 543         return 0;
 544
 545 error:
 546         free_trace_uprobe(tu);
 547         return ret;
 548
 549 fail_address_parse:
 550         path_put(&path);
 551
 552         pr_info("Failed to parse address or file.\n");
 553
 554         return ret;
 555 }
 556
 557 static int cleanup_all_probes(void)
 558 {
 559         struct trace_uprobe *tu;
 560         int ret = 0;
 561
 562         mutex_lock(&uprobe_lock);
 563         while (!list_empty(&uprobe_list)) {
 564                 tu = list_entry(uprobe_list.next, struct trace_uprobe, list);
 565                 ret = unregister_trace_uprobe(tu);
 566                 if (ret)
 567                         break;
 568         }
 569         mutex_unlock(&uprobe_lock);
 570         return ret;
 571 }
 572
 573 /* Probes listing interfaces */
 574 static void *probes_seq_start(struct seq_file *m, loff_t *pos)
 575 {
 576         mutex_lock(&uprobe_lock);
 577         return seq_list_start(&uprobe_list, *pos);
 578 }
 579
 580 static void *probes_seq_next(struct seq_file *m, void *v, loff_t *pos)
 581 {
 582         return seq_list_next(v, &uprobe_list, pos);
 583 }
 584
 585 static void probes_seq_stop(struct seq_file *m, void *v)
 586 {
 587         mutex_unlock(&uprobe_lock);
 588 }
 589
 590 static int probes_seq_show(struct seq_file *m, void *v)
 591 {
 592         struct trace_uprobe *tu = v;
 593         char c = is_ret_probe(tu) ? 'r' : 'p';
 594         int i;
 595
 596         seq_printf(m, "%c:%s/%s %s:0x%0*lx", c, tu->tp.call.class->system,
 597                         trace_event_name(&tu->tp.call), tu->filename,
 598                         (int)(sizeof(void *) * 2), tu->offset);
 599
 600         for (i = 0; i < tu->tp.nr_args; i++)
 601                 seq_printf(m, " %s=%s", tu->tp.args[i].name, tu->tp.args[i].comm);
 602
 603         seq_putc(m, '\n');
 604         return 0;
 605 }
 606
 607 static const struct seq_operations probes_seq_op = {
 608         .start  = probes_seq_start,
 609         .next   = probes_seq_next,
 610         .stop   = probes_seq_stop,
 611         .show   = probes_seq_show
 612 };
 613
 614 static int probes_open(struct inode *inode, struct file *file)
 615 {
 616         int ret;
 617
 618         if ((file->f_mode & FMODE_WRITE) && (file->f_flags & O_TRUNC)) {
 619                 ret = cleanup_all_probes();
 620                 if (ret)
 621                         return ret;
 622         }
 623
 624         return seq_open(file, &probes_seq_op);
 625 }
 626
 627 static ssize_t probes_write(struct file *file, const char __user *buffer,
 628                             size_t count, loff_t *ppos)
 629 {
 630         return trace_parse_run_command(file, buffer, count, ppos, create_trace_uprobe);
 631 }
 632
 633 static const struct file_operations uprobe_events_ops = {
 634         .owner          = THIS_MODULE,
 635         .open           = probes_open,
 636         .read           = seq_read,
 637         .llseek         = seq_lseek,
 638         .release        = seq_release,
 639         .write          = probes_write,
 640 };
 641
 642 /* Probes profiling interfaces */
 643 static int probes_profile_seq_show(struct seq_file *m, void *v)
 644 {
 645         struct trace_uprobe *tu = v;
 646
 647         seq_printf(m, "  %s %-44s %15lu\n", tu->filename,
 648                         trace_event_name(&tu->tp.call), tu->nhit);
 649         return 0;
 650 }
 651
 652 static const struct seq_operations profile_seq_op = {
 653         .start  = probes_seq_start,
 654         .next   = probes_seq_next,
 655         .stop   = probes_seq_stop,
 656         .show   = probes_profile_seq_show
 657 };
 658
 659 static int profile_open(struct inode *inode, struct file *file)
 660 {
 661         return seq_open(file, &profile_seq_op);
 662 }
 663
 664 static const struct file_operations uprobe_profile_ops = {
 665         .owner          = THIS_MODULE,
 666         .open           = profile_open,
 667         .read           = seq_read,
 668         .llseek         = seq_lseek,
 669         .release        = seq_release,
 670 };
 671
 672 struct uprobe_cpu_buffer {
 673         struct mutex mutex;
 674         void *buf;
 675 };
 676 static struct uprobe_cpu_buffer __percpu *uprobe_cpu_buffer;
 677 static int uprobe_buffer_refcnt;
 678
 679 static int uprobe_buffer_init(void)
 680 {
 681         int cpu, err_cpu;
 682
 683         uprobe_cpu_buffer = alloc_percpu(struct uprobe_cpu_buffer);
 684         if (uprobe_cpu_buffer == NULL)
 685                 return -ENOMEM;
 686
 687         for_each_possible_cpu(cpu) {
 688                 struct page *p = alloc_pages_node(cpu_to_node(cpu),
 689                                                   GFP_KERNEL, 0);
 690                 if (p == NULL) {
 691                         err_cpu = cpu;
 692                         goto err;
 693                 }
 694                 per_cpu_ptr(uprobe_cpu_buffer, cpu)->buf = page_address(p);
 695                 mutex_init(&per_cpu_ptr(uprobe_cpu_buffer, cpu)->mutex);
 696         }
 697
 698         return 0;
 699
 700 err:
 701         for_each_possible_cpu(cpu) {
 702                 if (cpu == err_cpu)
 703                         break;
 704                 free_page((unsigned long)per_cpu_ptr(uprobe_cpu_buffer, cpu)->buf);
 705         }
 706
 707         free_percpu(uprobe_cpu_buffer);
 708         return -ENOMEM;
 709 }
 710
 711 static int uprobe_buffer_enable(void)
 712 {
 713         int ret = 0;
 714
 715         BUG_ON(!mutex_is_locked(&event_mutex));
 716
 717         if (uprobe_buffer_refcnt++ == 0) {
 718                 ret = uprobe_buffer_init();
 719                 if (ret < 0)
 720                         uprobe_buffer_refcnt--;
 721         }
 722
 723         return ret;
 724 }
 725
 726 static void uprobe_buffer_disable(void)
 727 {
 728         int cpu;
 729
 730         BUG_ON(!mutex_is_locked(&event_mutex));
 731
 732         if (--uprobe_buffer_refcnt == 0) {
 733                 for_each_possible_cpu(cpu)
 734                         free_page((unsigned long)per_cpu_ptr(uprobe_cpu_buffer,
 735                                                              cpu)->buf);
 736
 737                 free_percpu(uprobe_cpu_buffer);
 738                 uprobe_cpu_buffer = NULL;
 739         }
 740 }
 741
 742 static struct uprobe_cpu_buffer *uprobe_buffer_get(void)
 743 {
 744         struct uprobe_cpu_buffer *ucb;
 745         int cpu;
 746
 747         cpu = raw_smp_processor_id();
 748         ucb = per_cpu_ptr(uprobe_cpu_buffer, cpu);
 749
 750         /*
 751          * Use per-cpu buffers for fastest access, but we might migrate
 752          * so the mutex makes sure we have sole access to it.
 753          */
 754         mutex_lock(&ucb->mutex);
 755
 756         return ucb;
 757 }
 758
 759 static void uprobe_buffer_put(struct uprobe_cpu_buffer *ucb)
 760 {
 761         mutex_unlock(&ucb->mutex);
 762 }
 763
 764 static void __uprobe_trace_func(struct trace_uprobe *tu,
 765                                 unsigned long func, struct pt_regs *regs,
 766                                 struct uprobe_cpu_buffer *ucb, int dsize,
 767                                 struct trace_event_file *trace_file)
 768 {
 769         struct uprobe_trace_entry_head *entry;
 770         struct ring_buffer_event *event;
 771         struct ring_buffer *buffer;
 772         void *data;
 773         int size, esize;
 774         struct trace_event_call *call = &tu->tp.call;
 775
 776         WARN_ON(call != trace_file->event_call);
 777
 778         if (WARN_ON_ONCE(tu->tp.size + dsize > PAGE_SIZE))
 779                 return;
 780
 781         if (trace_trigger_soft_disabled(trace_file))
 782                 return;
 783
 784         esize = SIZEOF_TRACE_ENTRY(is_ret_probe(tu));
 785         size = esize + tu->tp.size + dsize;
 786         event = trace_event_buffer_lock_reserve(&buffer, trace_file,
 787                                                 call->event.type, size, 0, 0);
 788         if (!event)
 789                 return;
 790
 791         entry = ring_buffer_event_data(event);
 792         if (is_ret_probe(tu)) {
 793                 entry->vaddr[0] = func;
 794                 entry->vaddr[1] = instruction_pointer(regs);
 795                 data = DATAOF_TRACE_ENTRY(entry, true);
 796         } else {
 797                 entry->vaddr[0] = instruction_pointer(regs);
 798                 data = DATAOF_TRACE_ENTRY(entry, false);
 799         }
 800
 801         memcpy(data, ucb->buf, tu->tp.size + dsize);
 802
 803         event_trigger_unlock_commit(trace_file, buffer, event, entry, 0, 0);
 804 }
 805
 806 /* uprobe handler */
 807 static int uprobe_trace_func(struct trace_uprobe *tu, struct pt_regs *regs,
 808                              struct uprobe_cpu_buffer *ucb, int dsize)
 809 {
 810         struct event_file_link *link;
 811
 812         if (is_ret_probe(tu))
 813                 return 0;
 814
 815         rcu_read_lock();
 816         list_for_each_entry_rcu(link, &tu->tp.files, list)
 817                 __uprobe_trace_func(tu, 0, regs, ucb, dsize, link->file);
 818         rcu_read_unlock();
 819
 820         return 0;
 821 }
 822
 823 static void uretprobe_trace_func(struct trace_uprobe *tu, unsigned long func,
 824                                  struct pt_regs *regs,
 825                                  struct uprobe_cpu_buffer *ucb, int dsize)
 826 {
 827         struct event_file_link *link;
 828
 829         rcu_read_lock();
 830         list_for_each_entry_rcu(link, &tu->tp.files, list)
 831                 __uprobe_trace_func(tu, func, regs, ucb, dsize, link->file);
 832         rcu_read_unlock();
 833 }
 834
 835 /* Event entry printers */
 836 static enum print_line_t
 837 print_uprobe_event(struct trace_iterator *iter, int flags, struct trace_event *event)
 838 {
 839         struct uprobe_trace_entry_head *entry;
 840         struct trace_seq *s = &iter->seq;
 841         struct trace_uprobe *tu;
 842         u8 *data;
 843         int i;
 844
 845         entry = (struct uprobe_trace_entry_head *)iter->ent;
 846         tu = container_of(event, struct trace_uprobe, tp.call.event);
 847
 848         if (is_ret_probe(tu)) {
 849                 trace_seq_printf(s, "%s: (0x%lx <- 0x%lx)",
 850                                  trace_event_name(&tu->tp.call),
 851                                  entry->vaddr[1], entry->vaddr[0]);
 852                 data = DATAOF_TRACE_ENTRY(entry, true);
 853         } else {
 854                 trace_seq_printf(s, "%s: (0x%lx)",
 855                                  trace_event_name(&tu->tp.call),
 856                                  entry->vaddr[0]);
 857                 data = DATAOF_TRACE_ENTRY(entry, false);
 858         }
 859
 860         for (i = 0; i < tu->tp.nr_args; i++) {
 861                 struct probe_arg *parg = &tu->tp.args[i];
 862
 863                 if (!parg->type->print(s, parg->name, data + parg->offset, entry))
 864                         goto out;
 865         }
 866
 867         trace_seq_putc(s, '\n');
 868
 869  out:
 870         return trace_handle_return(s);
 871 }
 872
 873 typedef bool (*filter_func_t)(struct uprobe_consumer *self,
 874                                 enum uprobe_filter_ctx ctx,
 875                                 struct mm_struct *mm);
 876
 877 static int
 878 probe_event_enable(struct trace_uprobe *tu, struct trace_event_file *file,
 879                    filter_func_t filter)
 880 {
 881         bool enabled = trace_probe_is_enabled(&tu->tp);
 882         struct event_file_link *link = NULL;
 883         int ret;
 884
 885         if (file) {
 886                 if (tu->tp.flags & TP_FLAG_PROFILE)
 887                         return -EINTR;
 888
 889                 link = kmalloc(sizeof(*link), GFP_KERNEL);
 890                 if (!link)
 891                         return -ENOMEM;
 892
 893                 link->file = file;
 894                 list_add_tail_rcu(&link->list, &tu->tp.files);
 895
 896                 tu->tp.flags |= TP_FLAG_TRACE;
 897         } else {
 898                 if (tu->tp.flags & TP_FLAG_TRACE)
 899                         return -EINTR;
 900
 901                 tu->tp.flags |= TP_FLAG_PROFILE;
 902         }
 903
 904         WARN_ON(!uprobe_filter_is_empty(&tu->filter));
 905
 906         if (enabled)
 907                 return 0;
 908
 909         ret = uprobe_buffer_enable();
 910         if (ret)
 911                 goto err_flags;
 912
 913         tu->consumer.filter = filter;
 914         tu->inode = d_real_inode(tu->path.dentry);
 915         ret = uprobe_register(tu->inode, tu->offset, &tu->consumer);
 916         if (ret)
 917                 goto err_buffer;
 918
 919         return 0;
 920
 921  err_buffer:
 922         uprobe_buffer_disable();
 923
 924  err_flags:
 925         if (file) {
 926                 list_del(&link->list);
 927                 kfree(link);
 928                 tu->tp.flags &= ~TP_FLAG_TRACE;
 929         } else {
 930                 tu->tp.flags &= ~TP_FLAG_PROFILE;
 931         }
 932         return ret;
 933 }
 934
 935 static void
 936 probe_event_disable(struct trace_uprobe *tu, struct trace_event_file *file)
 937 {
 938         if (!trace_probe_is_enabled(&tu->tp))
 939                 return;
 940
 941         if (file) {
 942                 struct event_file_link *link;
 943
 944                 link = find_event_file_link(&tu->tp, file);
 945                 if (!link)
 946                         return;
 947
 948                 list_del_rcu(&link->list);
 949                 /* synchronize with u{,ret}probe_trace_func */
 950                 synchronize_rcu();
 951                 kfree(link);
 952
 953                 if (!list_empty(&tu->tp.files))
 954                         return;
 955         }
 956
 957         WARN_ON(!uprobe_filter_is_empty(&tu->filter));
 958
 959         uprobe_unregister(tu->inode, tu->offset, &tu->consumer);
 960         tu->inode = NULL;
 961         tu->tp.flags &= file ? ~TP_FLAG_TRACE : ~TP_FLAG_PROFILE;
 962
 963         uprobe_buffer_disable();
 964 }
 965
 966 static int uprobe_event_define_fields(struct trace_event_call *event_call)
 967 {
 968         int ret, i, size;
 969         struct uprobe_trace_entry_head field;
 970         struct trace_uprobe *tu = event_call->data;
 971
 972         if (is_ret_probe(tu)) {
 973                 DEFINE_FIELD(unsigned long, vaddr[0], FIELD_STRING_FUNC, 0);
 974                 DEFINE_FIELD(unsigned long, vaddr[1], FIELD_STRING_RETIP, 0);
 975                 size = SIZEOF_TRACE_ENTRY(true);
 976         } else {
 977                 DEFINE_FIELD(unsigned long, vaddr[0], FIELD_STRING_IP, 0);
 978                 size = SIZEOF_TRACE_ENTRY(false);
 979         }
 980         /* Set argument names as fields */
 981         for (i = 0; i < tu->tp.nr_args; i++) {
 982                 struct probe_arg *parg = &tu->tp.args[i];
 983
 984                 ret = trace_define_field(event_call, parg->type->fmttype,
 985                                          parg->name, size + parg->offset,
 986                                          parg->type->size, parg->type->is_signed,
 987                                          FILTER_OTHER);
 988
 989                 if (ret)
 990                         return ret;
 991         }
 992         return 0;
 993 }
 994
 995 #ifdef CONFIG_PERF_EVENTS
 996 static bool
 997 __uprobe_perf_filter(struct trace_uprobe_filter *filter, struct mm_struct *mm)
 998 {
 999         struct perf_event *event;
1000
1001         if (filter->nr_systemwide)
1002                 return true;
1003
1004         list_for_each_entry(event, &filter->perf_events, hw.tp_list) {
1005                 if (event->hw.target->mm == mm)
1006                         return true;
1007         }
1008
1009         return false;
1010 }
1011
1012 static inline bool
1013 uprobe_filter_event(struct trace_uprobe *tu, struct perf_event *event)
1014 {
1015         return __uprobe_perf_filter(&tu->filter, event->hw.target->mm);
1016 }
1017
1018 static int uprobe_perf_close(struct trace_uprobe *tu, struct perf_event *event)
1019 {
1020         bool done;
1021
1022         write_lock(&tu->filter.rwlock);
1023         if (event->hw.target) {
1024                 list_del(&event->hw.tp_list);
1025                 done = tu->filter.nr_systemwide ||
1026                         (event->hw.target->flags & PF_EXITING) ||
1027                         uprobe_filter_event(tu, event);
1028         } else {
1029                 tu->filter.nr_systemwide--;
1030                 done = tu->filter.nr_systemwide;
1031         }
1032         write_unlock(&tu->filter.rwlock);
1033
1034         if (!done)
1035                 return uprobe_apply(tu->inode, tu->offset, &tu->consumer, false);
1036
1037         return 0;
1038 }
1039
1040 static int uprobe_perf_open(struct trace_uprobe *tu, struct perf_event *event)
1041 {
1042         bool done;
1043         int err;
1044
1045         write_lock(&tu->filter.rwlock);
1046         if (event->hw.target) {
1047                 /*
1048                  * event->parent != NULL means copy_process(), we can avoid
1049                  * uprobe_apply(). current->mm must be probed and we can rely
1050                  * on dup_mmap() which preserves the already installed bp's.
1051                  *
1052                  * attr.enable_on_exec means that exec/mmap will install the
1053                  * breakpoints we need.
1054                  */
1055                 done = tu->filter.nr_systemwide ||
1056                         event->parent || event->attr.enable_on_exec ||
1057                         uprobe_filter_event(tu, event);
1058                 list_add(&event->hw.tp_list, &tu->filter.perf_events);
1059         } else {
1060                 done = tu->filter.nr_systemwide;
1061                 tu->filter.nr_systemwide++;
1062         }
1063         write_unlock(&tu->filter.rwlock);
1064
1065         err = 0;
1066         if (!done) {
1067                 err = uprobe_apply(tu->inode, tu->offset, &tu->consumer, true);
1068                 if (err)
1069                         uprobe_perf_close(tu, event);
1070         }
1071         return err;
1072 }
1073
1074 static bool uprobe_perf_filter(struct uprobe_consumer *uc,
1075                                 enum uprobe_filter_ctx ctx, struct mm_struct *mm)
1076 {
1077         struct trace_uprobe *tu;
1078         int ret;
1079
1080         tu = container_of(uc, struct trace_uprobe, consumer);
1081         read_lock(&tu->filter.rwlock);
1082         ret = __uprobe_perf_filter(&tu->filter, mm);
1083         read_unlock(&tu->filter.rwlock);
1084
1085         return ret;
1086 }
1087
1088 static void __uprobe_perf_func(struct trace_uprobe *tu,
1089                                unsigned long func, struct pt_regs *regs,
1090                                struct uprobe_cpu_buffer *ucb, int dsize)
1091 {
1092         struct trace_event_call *call = &tu->tp.call;
1093         struct uprobe_trace_entry_head *entry;
1094         struct hlist_head *head;
1095         void *data;
1096         int size, esize;
1097         int rctx;
1098
1099         if (bpf_prog_array_valid(call) && !trace_call_bpf(call, regs))
1100                 return;
1101
1102         esize = SIZEOF_TRACE_ENTRY(is_ret_probe(tu));
1103
1104         size = esize + tu->tp.size + dsize;
1105         size = ALIGN(size + sizeof(u32), sizeof(u64)) - sizeof(u32);
1106         if (WARN_ONCE(size > PERF_MAX_TRACE_SIZE, "profile buffer not large enough"))
1107                 return;
1108
1109         preempt_disable();
1110         head = this_cpu_ptr(call->perf_events);
1111         if (hlist_empty(head))
1112                 goto out;
1113
1114         entry = perf_trace_buf_alloc(size, NULL, &rctx);
1115         if (!entry)
1116                 goto out;
1117
1118         if (is_ret_probe(tu)) {
1119                 entry->vaddr[0] = func;
1120                 entry->vaddr[1] = instruction_pointer(regs);
1121                 data = DATAOF_TRACE_ENTRY(entry, true);
1122         } else {
1123                 entry->vaddr[0] = instruction_pointer(regs);
1124                 data = DATAOF_TRACE_ENTRY(entry, false);
1125         }
1126
1127         memcpy(data, ucb->buf, tu->tp.size + dsize);
1128
1129         if (size - esize > tu->tp.size + dsize) {
1130                 int len = tu->tp.size + dsize;
1131
1132                 memset(data + len, 0, size - esize - len);
1133         }
1134
1135         perf_trace_buf_submit(entry, size, rctx, call->event.type, 1, regs,
1136                               head, NULL);
1137  out:
1138         preempt_enable();
1139 }
1140
1141 /* uprobe profile handler */
1142 static int uprobe_perf_func(struct trace_uprobe *tu, struct pt_regs *regs,
1143                             struct uprobe_cpu_buffer *ucb, int dsize)
1144 {
1145         if (!uprobe_perf_filter(&tu->consumer, 0, current->mm))
1146                 return UPROBE_HANDLER_REMOVE;
1147
1148         if (!is_ret_probe(tu))
1149                 __uprobe_perf_func(tu, 0, regs, ucb, dsize);
1150         return 0;
1151 }
1152
1153 static void uretprobe_perf_func(struct trace_uprobe *tu, unsigned long func,
1154                                 struct pt_regs *regs,
1155                                 struct uprobe_cpu_buffer *ucb, int dsize)
1156 {
1157         __uprobe_perf_func(tu, func, regs, ucb, dsize);
1158 }
1159
1160 int bpf_get_uprobe_info(const struct perf_event *event, u32 *fd_type,
1161                         const char **filename, u64 *probe_offset,
1162                         bool perf_type_tracepoint)
1163 {
1164         const char *pevent = trace_event_name(event->tp_event);
1165         const char *group = event->tp_event->class->system;
1166         struct trace_uprobe *tu;
1167
1168         if (perf_type_tracepoint)
1169                 tu = find_probe_event(pevent, group);
1170         else
1171                 tu = event->tp_event->data;
1172         if (!tu)
1173                 return -EINVAL;
1174
1175         *fd_type = is_ret_probe(tu) ? BPF_FD_TYPE_URETPROBE
1176                                     : BPF_FD_TYPE_UPROBE;
1177         *filename = tu->filename;
1178         *probe_offset = tu->offset;
1179         return 0;
1180 }
1181 #endif  /* CONFIG_PERF_EVENTS */
1182
1183 static int
1184 trace_uprobe_register(struct trace_event_call *event, enum trace_reg type,
1185                       void *data)
1186 {
1187         struct trace_uprobe *tu = event->data;
1188         struct trace_event_file *file = data;
1189
1190         switch (type) {
1191         case TRACE_REG_REGISTER:
1192                 return probe_event_enable(tu, file, NULL);
1193
1194         case TRACE_REG_UNREGISTER:
1195                 probe_event_disable(tu, file);
1196                 return 0;
1197
1198 #ifdef CONFIG_PERF_EVENTS
1199         case TRACE_REG_PERF_REGISTER:
1200                 return probe_event_enable(tu, NULL, uprobe_perf_filter);
1201
1202         case TRACE_REG_PERF_UNREGISTER:
1203                 probe_event_disable(tu, NULL);
1204                 return 0;
1205
1206         case TRACE_REG_PERF_OPEN:
1207                 return uprobe_perf_open(tu, data);
1208
1209         case TRACE_REG_PERF_CLOSE:
1210                 return uprobe_perf_close(tu, data);
1211
1212 #endif
1213         default:
1214                 return 0;
1215         }
1216         return 0;
1217 }
1218
1219 static int uprobe_dispatcher(struct uprobe_consumer *con, struct pt_regs *regs)
1220 {
1221         struct trace_uprobe *tu;
1222         struct uprobe_dispatch_data udd;
1223         struct uprobe_cpu_buffer *ucb;
1224         int dsize, esize;
1225         int ret = 0;
1226
1227
1228         tu = container_of(con, struct trace_uprobe, consumer);
1229         tu->nhit++;
1230
1231         udd.tu = tu;
1232         udd.bp_addr = instruction_pointer(regs);
1233
1234         current->utask->vaddr = (unsigned long) &udd;
1235
1236         if (WARN_ON_ONCE(!uprobe_cpu_buffer))
1237                 return 0;
1238
1239         dsize = __get_data_size(&tu->tp, regs);
1240         esize = SIZEOF_TRACE_ENTRY(is_ret_probe(tu));
1241
1242         ucb = uprobe_buffer_get();
1243         store_trace_args(esize, &tu->tp, regs, ucb->buf, dsize);
1244
1245         if (tu->tp.flags & TP_FLAG_TRACE)
1246                 ret |= uprobe_trace_func(tu, regs, ucb, dsize);
1247
1248 #ifdef CONFIG_PERF_EVENTS
1249         if (tu->tp.flags & TP_FLAG_PROFILE)
1250                 ret |= uprobe_perf_func(tu, regs, ucb, dsize);
1251 #endif
1252         uprobe_buffer_put(ucb);
1253         return ret;
1254 }
1255
1256 static int uretprobe_dispatcher(struct uprobe_consumer *con,
1257                                 unsigned long func, struct pt_regs *regs)
1258 {
1259         struct trace_uprobe *tu;
1260         struct uprobe_dispatch_data udd;
1261         struct uprobe_cpu_buffer *ucb;
1262         int dsize, esize;
1263
1264         tu = container_of(con, struct trace_uprobe, consumer);
1265
1266         udd.tu = tu;
1267         udd.bp_addr = func;
1268
1269         current->utask->vaddr = (unsigned long) &udd;
1270
1271         if (WARN_ON_ONCE(!uprobe_cpu_buffer))
1272                 return 0;
1273
1274         dsize = __get_data_size(&tu->tp, regs);
1275         esize = SIZEOF_TRACE_ENTRY(is_ret_probe(tu));
1276
1277         ucb = uprobe_buffer_get();
1278         store_trace_args(esize, &tu->tp, regs, ucb->buf, dsize);
1279
1280         if (tu->tp.flags & TP_FLAG_TRACE)
1281                 uretprobe_trace_func(tu, func, regs, ucb, dsize);
1282
1283 #ifdef CONFIG_PERF_EVENTS
1284         if (tu->tp.flags & TP_FLAG_PROFILE)
1285                 uretprobe_perf_func(tu, func, regs, ucb, dsize);
1286 #endif
1287         uprobe_buffer_put(ucb);
1288         return 0;
1289 }
1290
1291 static struct trace_event_functions uprobe_funcs = {
1292         .trace          = print_uprobe_event
1293 };
1294
1295 static inline void init_trace_event_call(struct trace_uprobe *tu,
1296                                          struct trace_event_call *call)
1297 {
1298         INIT_LIST_HEAD(&call->class->fields);
1299         call->event.funcs = &uprobe_funcs;
1300         call->class->define_fields = uprobe_event_define_fields;
1301
1302         call->flags = TRACE_EVENT_FL_UPROBE;
1303         call->class->reg = trace_uprobe_register;
1304         call->data = tu;
1305 }
1306
1307 static int register_uprobe_event(struct trace_uprobe *tu)
1308 {
1309         struct trace_event_call *call = &tu->tp.call;
1310         int ret = 0;
1311
1312         init_trace_event_call(tu, call);
1313
1314         if (set_print_fmt(&tu->tp, is_ret_probe(tu)) < 0)
1315                 return -ENOMEM;
1316
1317         ret = register_trace_event(&call->event);
1318         if (!ret) {
1319                 kfree(call->print_fmt);
1320                 return -ENODEV;
1321         }
1322
1323         ret = trace_add_event_call(call);
1324
1325         if (ret) {
1326                 pr_info("Failed to register uprobe event: %s\n",
1327                         trace_event_name(call));
1328                 kfree(call->print_fmt);
1329                 unregister_trace_event(&call->event);
1330         }
1331
1332         return ret;
1333 }
1334
1335 static int unregister_uprobe_event(struct trace_uprobe *tu)
1336 {
1337         int ret;
1338
1339         /* tu->event is unregistered in trace_remove_event_call() */
1340         ret = trace_remove_event_call(&tu->tp.call);
1341         if (ret)
1342                 return ret;
1343         kfree(tu->tp.call.print_fmt);
1344         tu->tp.call.print_fmt = NULL;
1345         return 0;
1346 }
1347
1348 #ifdef CONFIG_PERF_EVENTS
1349 struct trace_event_call *
1350 create_local_trace_uprobe(char *name, unsigned long offs, bool is_return)
1351 {
1352         struct trace_uprobe *tu;
1353         struct path path;
1354         int ret;
1355
1356         ret = kern_path(name, LOOKUP_FOLLOW, &path);
1357         if (ret)
1358                 return ERR_PTR(ret);
1359
1360         if (!d_is_reg(path.dentry)) {
1361                 path_put(&path);
1362                 return ERR_PTR(-EINVAL);
1363         }
1364
1365         /*
1366          * local trace_kprobes are not added to probe_list, so they are never
1367          * searched in find_trace_kprobe(). Therefore, there is no concern of
1368          * duplicated name "DUMMY_EVENT" here.
1369          */
1370         tu = alloc_trace_uprobe(UPROBE_EVENT_SYSTEM, "DUMMY_EVENT", 0,
1371                                 is_return);
1372
1373         if (IS_ERR(tu)) {
1374                 pr_info("Failed to allocate trace_uprobe.(%d)\n",
1375                         (int)PTR_ERR(tu));
1376                 path_put(&path);
1377                 return ERR_CAST(tu);
1378         }
1379
1380         tu->offset = offs;
1381         tu->path = path;
1382         tu->filename = kstrdup(name, GFP_KERNEL);
1383         init_trace_event_call(tu, &tu->tp.call);
1384
1385         if (set_print_fmt(&tu->tp, is_ret_probe(tu)) < 0) {
1386                 ret = -ENOMEM;
1387                 goto error;
1388         }
1389
1390         return &tu->tp.call;
1391 error:
1392         free_trace_uprobe(tu);
1393         return ERR_PTR(ret);
1394 }
1395
1396 void destroy_local_trace_uprobe(struct trace_event_call *event_call)
1397 {
1398         struct trace_uprobe *tu;
1399
1400         tu = container_of(event_call, struct trace_uprobe, tp.call);
1401
1402         kfree(tu->tp.call.print_fmt);
1403         tu->tp.call.print_fmt = NULL;
1404
1405         free_trace_uprobe(tu);
1406 }
1407 #endif /* CONFIG_PERF_EVENTS */
1408
1409 /* Make a trace interface for controling probe points */
1410 static __init int init_uprobe_trace(void)
1411 {
1412         struct dentry *d_tracer;
1413
1414         d_tracer = tracing_init_dentry();
1415         if (IS_ERR(d_tracer))
1416                 return 0;
1417
1418         trace_create_file("uprobe_events", 0644, d_tracer,
1419                                     NULL, &uprobe_events_ops);
1420         /* Profile interface */
1421         trace_create_file("uprobe_profile", 0444, d_tracer,
1422                                     NULL, &uprobe_profile_ops);
1423         return 0;
1424 }
1425
1426 fs_initcall(init_uprobe_trace);