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/ctype.h>
  11 #include <linux/module.h>
  12 #include <linux/uaccess.h>
  13 #include <linux/uprobes.h>
  14 #include <linux/namei.h>
  15 #include <linux/string.h>
  16 #include <linux/rculist.h>
  17
  18 #include "trace_dynevent.h"
  19 #include "trace_probe.h"
  20 #include "trace_probe_tmpl.h"
  21
  22 #define UPROBE_EVENT_SYSTEM     "uprobes"
  23
  24 struct uprobe_trace_entry_head {
  25         struct trace_entry      ent;
  26         unsigned long           vaddr[];
  27 };
  28
  29 #define SIZEOF_TRACE_ENTRY(is_return)                   \
  30         (sizeof(struct uprobe_trace_entry_head) +       \
  31          sizeof(unsigned long) * (is_return ? 2 : 1))
  32
  33 #define DATAOF_TRACE_ENTRY(entry, is_return)            \
  34         ((void*)(entry) + SIZEOF_TRACE_ENTRY(is_return))
  35
  36 struct trace_uprobe_filter {
  37         rwlock_t                rwlock;
  38         int                     nr_systemwide;
  39         struct list_head        perf_events;
  40 };
  41
  42 static int trace_uprobe_create(int argc, const char **argv);
  43 static int trace_uprobe_show(struct seq_file *m, struct dyn_event *ev);
  44 static int trace_uprobe_release(struct dyn_event *ev);
  45 static bool trace_uprobe_is_busy(struct dyn_event *ev);
  46 static bool trace_uprobe_match(const char *system, const char *event,
  47                                struct dyn_event *ev);
  48
  49 static struct dyn_event_operations trace_uprobe_ops = {
  50         .create = trace_uprobe_create,
  51         .show = trace_uprobe_show,
  52         .is_busy = trace_uprobe_is_busy,
  53         .free = trace_uprobe_release,
  54         .match = trace_uprobe_match,
  55 };
  56
  57 /*
  58  * uprobe event core functions
  59  */
  60 struct trace_uprobe {
  61         struct dyn_event                devent;
  62         struct trace_uprobe_filter      filter;
  63         struct uprobe_consumer          consumer;
  64         struct path                     path;
  65         struct inode                    *inode;
  66         char                            *filename;
  67         unsigned long                   offset;
  68         unsigned long                   ref_ctr_offset;
  69         unsigned long                   nhit;
  70         struct trace_probe              tp;
  71 };
  72
  73 static bool is_trace_uprobe(struct dyn_event *ev)
  74 {
  75         return ev->ops == &trace_uprobe_ops;
  76 }
  77
  78 static struct trace_uprobe *to_trace_uprobe(struct dyn_event *ev)
  79 {
  80         return container_of(ev, struct trace_uprobe, devent);
  81 }
  82
  83 /**
  84  * for_each_trace_uprobe - iterate over the trace_uprobe list
  85  * @pos:        the struct trace_uprobe * for each entry
  86  * @dpos:       the struct dyn_event * to use as a loop cursor
  87  */
  88 #define for_each_trace_uprobe(pos, dpos)        \
  89         for_each_dyn_event(dpos)                \
  90                 if (is_trace_uprobe(dpos) && (pos = to_trace_uprobe(dpos)))
  91
  92 #define SIZEOF_TRACE_UPROBE(n)                          \
  93         (offsetof(struct trace_uprobe, tp.args) +       \
  94         (sizeof(struct probe_arg) * (n)))
  95
  96 static int register_uprobe_event(struct trace_uprobe *tu);
  97 static int unregister_uprobe_event(struct trace_uprobe *tu);
  98
  99 struct uprobe_dispatch_data {
 100         struct trace_uprobe     *tu;
 101         unsigned long           bp_addr;
 102 };
 103
 104 static int uprobe_dispatcher(struct uprobe_consumer *con, struct pt_regs *regs);
 105 static int uretprobe_dispatcher(struct uprobe_consumer *con,
 106                                 unsigned long func, struct pt_regs *regs);
 107
 108 #ifdef CONFIG_STACK_GROWSUP
 109 static unsigned long adjust_stack_addr(unsigned long addr, unsigned int n)
 110 {
 111         return addr - (n * sizeof(long));
 112 }
 113 #else
 114 static unsigned long adjust_stack_addr(unsigned long addr, unsigned int n)
 115 {
 116         return addr + (n * sizeof(long));
 117 }
 118 #endif
 119
 120 static unsigned long get_user_stack_nth(struct pt_regs *regs, unsigned int n)
 121 {
 122         unsigned long ret;
 123         unsigned long addr = user_stack_pointer(regs);
 124
 125         addr = adjust_stack_addr(addr, n);
 126
 127         if (copy_from_user(&ret, (void __force __user *) addr, sizeof(ret)))
 128                 return 0;
 129
 130         return ret;
 131 }
 132
 133 /*
 134  * Uprobes-specific fetch functions
 135  */
 136 static nokprobe_inline int
 137 probe_mem_read(void *dest, void *src, size_t size)
 138 {
 139         void __user *vaddr = (void __force __user *)src;
 140
 141         return copy_from_user(dest, vaddr, size) ? -EFAULT : 0;
 142 }
 143
 144 static nokprobe_inline int
 145 probe_mem_read_user(void *dest, void *src, size_t size)
 146 {
 147         return probe_mem_read(dest, src, size);
 148 }
 149
 150 /*
 151  * Fetch a null-terminated string. Caller MUST set *(u32 *)dest with max
 152  * length and relative data location.
 153  */
 154 static nokprobe_inline int
 155 fetch_store_string(unsigned long addr, void *dest, void *base)
 156 {
 157         long ret;
 158         u32 loc = *(u32 *)dest;
 159         int maxlen  = get_loc_len(loc);
 160         u8 *dst = get_loc_data(dest, base);
 161         void __user *src = (void __force __user *) addr;
 162
 163         if (unlikely(!maxlen))
 164                 return -ENOMEM;
 165
 166         if (addr == FETCH_TOKEN_COMM)
 167                 ret = strlcpy(dst, current->comm, maxlen);
 168         else
 169                 ret = strncpy_from_user(dst, src, maxlen);
 170         if (ret >= 0) {
 171                 if (ret == maxlen)
 172                         dst[ret - 1] = '\0';
 173                 else
 174                         /*
 175                          * Include the terminating null byte. In this case it
 176                          * was copied by strncpy_from_user but not accounted
 177                          * for in ret.
 178                          */
 179                         ret++;
 180                 *(u32 *)dest = make_data_loc(ret, (void *)dst - base);
 181         }
 182
 183         return ret;
 184 }
 185
 186 static nokprobe_inline int
 187 fetch_store_string_user(unsigned long addr, void *dest, void *base)
 188 {
 189         return fetch_store_string(addr, dest, base);
 190 }
 191
 192 /* Return the length of string -- including null terminal byte */
 193 static nokprobe_inline int
 194 fetch_store_strlen(unsigned long addr)
 195 {
 196         int len;
 197         void __user *vaddr = (void __force __user *) addr;
 198
 199         if (addr == FETCH_TOKEN_COMM)
 200                 len = strlen(current->comm) + 1;
 201         else
 202                 len = strnlen_user(vaddr, MAX_STRING_SIZE);
 203
 204         return (len > MAX_STRING_SIZE) ? 0 : len;
 205 }
 206
 207 static nokprobe_inline int
 208 fetch_store_strlen_user(unsigned long addr)
 209 {
 210         return fetch_store_strlen(addr);
 211 }
 212
 213 static unsigned long translate_user_vaddr(unsigned long file_offset)
 214 {
 215         unsigned long base_addr;
 216         struct uprobe_dispatch_data *udd;
 217
 218         udd = (void *) current->utask->vaddr;
 219
 220         base_addr = udd->bp_addr - udd->tu->offset;
 221         return base_addr + file_offset;
 222 }
 223
 224 /* Note that we don't verify it, since the code does not come from user space */
 225 static int
 226 process_fetch_insn(struct fetch_insn *code, struct pt_regs *regs, void *dest,
 227                    void *base)
 228 {
 229         unsigned long val;
 230
 231         /* 1st stage: get value from context */
 232         switch (code->op) {
 233         case FETCH_OP_REG:
 234                 val = regs_get_register(regs, code->param);
 235                 break;
 236         case FETCH_OP_STACK:
 237                 val = get_user_stack_nth(regs, code->param);
 238                 break;
 239         case FETCH_OP_STACKP:
 240                 val = user_stack_pointer(regs);
 241                 break;
 242         case FETCH_OP_RETVAL:
 243                 val = regs_return_value(regs);
 244                 break;
 245         case FETCH_OP_IMM:
 246                 val = code->immediate;
 247                 break;
 248         case FETCH_OP_COMM:
 249                 val = FETCH_TOKEN_COMM;
 250                 break;
 251         case FETCH_OP_FOFFS:
 252                 val = translate_user_vaddr(code->immediate);
 253                 break;
 254         default:
 255                 return -EILSEQ;
 256         }
 257         code++;
 258
 259         return process_fetch_insn_bottom(code, val, dest, base);
 260 }
 261 NOKPROBE_SYMBOL(process_fetch_insn)
 262
 263 static inline void init_trace_uprobe_filter(struct trace_uprobe_filter *filter)
 264 {
 265         rwlock_init(&filter->rwlock);
 266         filter->nr_systemwide = 0;
 267         INIT_LIST_HEAD(&filter->perf_events);
 268 }
 269
 270 static inline bool uprobe_filter_is_empty(struct trace_uprobe_filter *filter)
 271 {
 272         return !filter->nr_systemwide && list_empty(&filter->perf_events);
 273 }
 274
 275 static inline bool is_ret_probe(struct trace_uprobe *tu)
 276 {
 277         return tu->consumer.ret_handler != NULL;
 278 }
 279
 280 static bool trace_uprobe_is_busy(struct dyn_event *ev)
 281 {
 282         struct trace_uprobe *tu = to_trace_uprobe(ev);
 283
 284         return trace_probe_is_enabled(&tu->tp);
 285 }
 286
 287 static bool trace_uprobe_match(const char *system, const char *event,
 288                                struct dyn_event *ev)
 289 {
 290         struct trace_uprobe *tu = to_trace_uprobe(ev);
 291
 292         return strcmp(trace_event_name(&tu->tp.call), event) == 0 &&
 293                 (!system || strcmp(tu->tp.call.class->system, system) == 0);
 294 }
 295
 296 /*
 297  * Allocate new trace_uprobe and initialize it (including uprobes).
 298  */
 299 static struct trace_uprobe *
 300 alloc_trace_uprobe(const char *group, const char *event, int nargs, bool is_ret)
 301 {
 302         struct trace_uprobe *tu;
 303
 304         if (!event || !group)
 305                 return ERR_PTR(-EINVAL);
 306
 307         tu = kzalloc(SIZEOF_TRACE_UPROBE(nargs), GFP_KERNEL);
 308         if (!tu)
 309                 return ERR_PTR(-ENOMEM);
 310
 311         tu->tp.call.class = &tu->tp.class;
 312         tu->tp.call.name = kstrdup(event, GFP_KERNEL);
 313         if (!tu->tp.call.name)
 314                 goto error;
 315
 316         tu->tp.class.system = kstrdup(group, GFP_KERNEL);
 317         if (!tu->tp.class.system)
 318                 goto error;
 319
 320         dyn_event_init(&tu->devent, &trace_uprobe_ops);
 321         INIT_LIST_HEAD(&tu->tp.files);
 322         tu->consumer.handler = uprobe_dispatcher;
 323         if (is_ret)
 324                 tu->consumer.ret_handler = uretprobe_dispatcher;
 325         init_trace_uprobe_filter(&tu->filter);
 326         return tu;
 327
 328 error:
 329         kfree(tu->tp.call.name);
 330         kfree(tu);
 331
 332         return ERR_PTR(-ENOMEM);
 333 }
 334
 335 static void free_trace_uprobe(struct trace_uprobe *tu)
 336 {
 337         int i;
 338
 339         if (!tu)
 340                 return;
 341
 342         for (i = 0; i < tu->tp.nr_args; i++)
 343                 traceprobe_free_probe_arg(&tu->tp.args[i]);
 344
 345         path_put(&tu->path);
 346         kfree(tu->tp.call.class->system);
 347         kfree(tu->tp.call.name);
 348         kfree(tu->tp.call.print_fmt);
 349         kfree(tu->filename);
 350         kfree(tu);
 351 }
 352
 353 static struct trace_uprobe *find_probe_event(const char *event, const char *group)
 354 {
 355         struct dyn_event *pos;
 356         struct trace_uprobe *tu;
 357
 358         for_each_trace_uprobe(tu, pos)
 359                 if (strcmp(trace_event_name(&tu->tp.call), event) == 0 &&
 360                     strcmp(tu->tp.call.class->system, group) == 0)
 361                         return tu;
 362
 363         return NULL;
 364 }
 365
 366 /* Unregister a trace_uprobe and probe_event */
 367 static int unregister_trace_uprobe(struct trace_uprobe *tu)
 368 {
 369         int ret;
 370
 371         ret = unregister_uprobe_event(tu);
 372         if (ret)
 373                 return ret;
 374
 375         dyn_event_remove(&tu->devent);
 376         free_trace_uprobe(tu);
 377         return 0;
 378 }
 379
 380 /*
 381  * Uprobe with multiple reference counter is not allowed. i.e.
 382  * If inode and offset matches, reference counter offset *must*
 383  * match as well. Though, there is one exception: If user is
 384  * replacing old trace_uprobe with new one(same group/event),
 385  * then we allow same uprobe with new reference counter as far
 386  * as the new one does not conflict with any other existing
 387  * ones.
 388  */
 389 static struct trace_uprobe *find_old_trace_uprobe(struct trace_uprobe *new)
 390 {
 391         struct dyn_event *pos;
 392         struct trace_uprobe *tmp, *old = NULL;
 393         struct inode *new_inode = d_real_inode(new->path.dentry);
 394
 395         old = find_probe_event(trace_event_name(&new->tp.call),
 396                                 new->tp.call.class->system);
 397
 398         for_each_trace_uprobe(tmp, pos) {
 399                 if ((old ? old != tmp : true) &&
 400                     new_inode == d_real_inode(tmp->path.dentry) &&
 401                     new->offset == tmp->offset &&
 402                     new->ref_ctr_offset != tmp->ref_ctr_offset) {
 403                         pr_warn("Reference counter offset mismatch.");
 404                         return ERR_PTR(-EINVAL);
 405                 }
 406         }
 407         return old;
 408 }
 409
 410 /* Register a trace_uprobe and probe_event */
 411 static int register_trace_uprobe(struct trace_uprobe *tu)
 412 {
 413         struct trace_uprobe *old_tu;
 414         int ret;
 415
 416         mutex_lock(&event_mutex);
 417
 418         /* register as an event */
 419         old_tu = find_old_trace_uprobe(tu);
 420         if (IS_ERR(old_tu)) {
 421                 ret = PTR_ERR(old_tu);
 422                 goto end;
 423         }
 424
 425         if (old_tu) {
 426                 /* delete old event */
 427                 ret = unregister_trace_uprobe(old_tu);
 428                 if (ret)
 429                         goto end;
 430         }
 431
 432         ret = register_uprobe_event(tu);
 433         if (ret) {
 434                 pr_warn("Failed to register probe event(%d)\n", ret);
 435                 goto end;
 436         }
 437
 438         dyn_event_add(&tu->devent);
 439
 440 end:
 441         mutex_unlock(&event_mutex);
 442
 443         return ret;
 444 }
 445
 446 /*
 447  * Argument syntax:
 448  *  - Add uprobe: p|r[:[GRP/]EVENT] PATH:OFFSET [FETCHARGS]
 449  *
 450  *  - Remove uprobe: -:[GRP/]EVENT
 451  */
 452 static int trace_uprobe_create(int argc, const char **argv)
 453 {
 454         struct trace_uprobe *tu;
 455         const char *event = NULL, *group = UPROBE_EVENT_SYSTEM;
 456         char *arg, *filename, *rctr, *rctr_end, *tmp;
 457         char buf[MAX_EVENT_NAME_LEN];
 458         struct path path;
 459         unsigned long offset, ref_ctr_offset;
 460         bool is_return = false;
 461         int i, ret;
 462
 463         ret = 0;
 464         ref_ctr_offset = 0;
 465
 466         /* argc must be >= 1 */
 467         if (argv[0][0] == 'r')
 468                 is_return = true;
 469         else if (argv[0][0] != 'p' || argc < 2)
 470                 return -ECANCELED;
 471
 472         if (argv[0][1] == ':')
 473                 event = &argv[0][2];
 474
 475         if (!strchr(argv[1], '/'))
 476                 return -ECANCELED;
 477
 478         filename = kstrdup(argv[1], GFP_KERNEL);
 479         if (!filename)
 480                 return -ENOMEM;
 481
 482         /* Find the last occurrence, in case the path contains ':' too. */
 483         arg = strrchr(filename, ':');
 484         if (!arg || !isdigit(arg[1])) {
 485                 kfree(filename);
 486                 return -ECANCELED;
 487         }
 488
 489         trace_probe_log_init("trace_uprobe", argc, argv);
 490         trace_probe_log_set_index(1);   /* filename is the 2nd argument */
 491
 492         *arg++ = '\0';
 493         ret = kern_path(filename, LOOKUP_FOLLOW, &path);
 494         if (ret) {
 495                 trace_probe_log_err(0, FILE_NOT_FOUND);
 496                 kfree(filename);
 497                 trace_probe_log_clear();
 498                 return ret;
 499         }
 500         if (!d_is_reg(path.dentry)) {
 501                 trace_probe_log_err(0, NO_REGULAR_FILE);
 502                 ret = -EINVAL;
 503                 goto fail_address_parse;
 504         }
 505
 506         /* Parse reference counter offset if specified. */
 507         rctr = strchr(arg, '(');
 508         if (rctr) {
 509                 rctr_end = strchr(rctr, ')');
 510                 if (!rctr_end) {
 511                         ret = -EINVAL;
 512                         rctr_end = rctr + strlen(rctr);
 513                         trace_probe_log_err(rctr_end - filename,
 514                                             REFCNT_OPEN_BRACE);
 515                         goto fail_address_parse;
 516                 } else if (rctr_end[1] != '\0') {
 517                         ret = -EINVAL;
 518                         trace_probe_log_err(rctr_end + 1 - filename,
 519                                             BAD_REFCNT_SUFFIX);
 520                         goto fail_address_parse;
 521                 }
 522
 523                 *rctr++ = '\0';
 524                 *rctr_end = '\0';
 525                 ret = kstrtoul(rctr, 0, &ref_ctr_offset);
 526                 if (ret) {
 527                         trace_probe_log_err(rctr - filename, BAD_REFCNT);
 528                         goto fail_address_parse;
 529                 }
 530         }
 531
 532         /* Parse uprobe offset. */
 533         ret = kstrtoul(arg, 0, &offset);
 534         if (ret) {
 535                 trace_probe_log_err(arg - filename, BAD_UPROBE_OFFS);
 536                 goto fail_address_parse;
 537         }
 538
 539         /* setup a probe */
 540         trace_probe_log_set_index(0);
 541         if (event) {
 542                 ret = traceprobe_parse_event_name(&event, &group, buf,
 543                                                   event - argv[0]);
 544                 if (ret)
 545                         goto fail_address_parse;
 546         } else {
 547                 char *tail;
 548                 char *ptr;
 549
 550                 tail = kstrdup(kbasename(filename), GFP_KERNEL);
 551                 if (!tail) {
 552                         ret = -ENOMEM;
 553                         goto fail_address_parse;
 554                 }
 555
 556                 ptr = strpbrk(tail, ".-_");
 557                 if (ptr)
 558                         *ptr = '\0';
 559
 560                 snprintf(buf, MAX_EVENT_NAME_LEN, "%c_%s_0x%lx", 'p', tail, offset);
 561                 event = buf;
 562                 kfree(tail);
 563         }
 564
 565         argc -= 2;
 566         argv += 2;
 567
 568         tu = alloc_trace_uprobe(group, event, argc, is_return);
 569         if (IS_ERR(tu)) {
 570                 ret = PTR_ERR(tu);
 571                 /* This must return -ENOMEM otherwise there is a bug */
 572                 WARN_ON_ONCE(ret != -ENOMEM);
 573                 goto fail_address_parse;
 574         }
 575         tu->offset = offset;
 576         tu->ref_ctr_offset = ref_ctr_offset;
 577         tu->path = path;
 578         tu->filename = filename;
 579
 580         /* parse arguments */
 581         for (i = 0; i < argc && i < MAX_TRACE_ARGS; i++) {
 582                 tmp = kstrdup(argv[i], GFP_KERNEL);
 583                 if (!tmp) {
 584                         ret = -ENOMEM;
 585                         goto error;
 586                 }
 587
 588                 trace_probe_log_set_index(i + 2);
 589                 ret = traceprobe_parse_probe_arg(&tu->tp, i, tmp,
 590                                         is_return ? TPARG_FL_RETURN : 0);
 591                 kfree(tmp);
 592                 if (ret)
 593                         goto error;
 594         }
 595
 596         ret = traceprobe_set_print_fmt(&tu->tp, is_ret_probe(tu));
 597         if (ret < 0)
 598                 goto error;
 599
 600         ret = register_trace_uprobe(tu);
 601         if (!ret)
 602                 goto out;
 603
 604 error:
 605         free_trace_uprobe(tu);
 606 out:
 607         trace_probe_log_clear();
 608         return ret;
 609
 610 fail_address_parse:
 611         trace_probe_log_clear();
 612         path_put(&path);
 613         kfree(filename);
 614
 615         return ret;
 616 }
 617
 618 static int create_or_delete_trace_uprobe(int argc, char **argv)
 619 {
 620         int ret;
 621
 622         if (argv[0][0] == '-')
 623                 return dyn_event_release(argc, argv, &trace_uprobe_ops);
 624
 625         ret = trace_uprobe_create(argc, (const char **)argv);
 626         return ret == -ECANCELED ? -EINVAL : ret;
 627 }
 628
 629 static int trace_uprobe_release(struct dyn_event *ev)
 630 {
 631         struct trace_uprobe *tu = to_trace_uprobe(ev);
 632
 633         return unregister_trace_uprobe(tu);
 634 }
 635
 636 /* Probes listing interfaces */
 637 static int trace_uprobe_show(struct seq_file *m, struct dyn_event *ev)
 638 {
 639         struct trace_uprobe *tu = to_trace_uprobe(ev);
 640         char c = is_ret_probe(tu) ? 'r' : 'p';
 641         int i;
 642
 643         seq_printf(m, "%c:%s/%s %s:0x%0*lx", c, tu->tp.call.class->system,
 644                         trace_event_name(&tu->tp.call), tu->filename,
 645                         (int)(sizeof(void *) * 2), tu->offset);
 646
 647         if (tu->ref_ctr_offset)
 648                 seq_printf(m, "(0x%lx)", tu->ref_ctr_offset);
 649
 650         for (i = 0; i < tu->tp.nr_args; i++)
 651                 seq_printf(m, " %s=%s", tu->tp.args[i].name, tu->tp.args[i].comm);
 652
 653         seq_putc(m, '\n');
 654         return 0;
 655 }
 656
 657 static int probes_seq_show(struct seq_file *m, void *v)
 658 {
 659         struct dyn_event *ev = v;
 660
 661         if (!is_trace_uprobe(ev))
 662                 return 0;
 663
 664         return trace_uprobe_show(m, ev);
 665 }
 666
 667 static const struct seq_operations probes_seq_op = {
 668         .start  = dyn_event_seq_start,
 669         .next   = dyn_event_seq_next,
 670         .stop   = dyn_event_seq_stop,
 671         .show   = probes_seq_show
 672 };
 673
 674 static int probes_open(struct inode *inode, struct file *file)
 675 {
 676         int ret;
 677
 678         if ((file->f_mode & FMODE_WRITE) && (file->f_flags & O_TRUNC)) {
 679                 ret = dyn_events_release_all(&trace_uprobe_ops);
 680                 if (ret)
 681                         return ret;
 682         }
 683
 684         return seq_open(file, &probes_seq_op);
 685 }
 686
 687 static ssize_t probes_write(struct file *file, const char __user *buffer,
 688                             size_t count, loff_t *ppos)
 689 {
 690         return trace_parse_run_command(file, buffer, count, ppos,
 691                                         create_or_delete_trace_uprobe);
 692 }
 693
 694 static const struct file_operations uprobe_events_ops = {
 695         .owner          = THIS_MODULE,
 696         .open           = probes_open,
 697         .read           = seq_read,
 698         .llseek         = seq_lseek,
 699         .release        = seq_release,
 700         .write          = probes_write,
 701 };
 702
 703 /* Probes profiling interfaces */
 704 static int probes_profile_seq_show(struct seq_file *m, void *v)
 705 {
 706         struct dyn_event *ev = v;
 707         struct trace_uprobe *tu;
 708
 709         if (!is_trace_uprobe(ev))
 710                 return 0;
 711
 712         tu = to_trace_uprobe(ev);
 713         seq_printf(m, "  %s %-44s %15lu\n", tu->filename,
 714                         trace_event_name(&tu->tp.call), tu->nhit);
 715         return 0;
 716 }
 717
 718 static const struct seq_operations profile_seq_op = {
 719         .start  = dyn_event_seq_start,
 720         .next   = dyn_event_seq_next,
 721         .stop   = dyn_event_seq_stop,
 722         .show   = probes_profile_seq_show
 723 };
 724
 725 static int profile_open(struct inode *inode, struct file *file)
 726 {
 727         return seq_open(file, &profile_seq_op);
 728 }
 729
 730 static const struct file_operations uprobe_profile_ops = {
 731         .owner          = THIS_MODULE,
 732         .open           = profile_open,
 733         .read           = seq_read,
 734         .llseek         = seq_lseek,
 735         .release        = seq_release,
 736 };
 737
 738 struct uprobe_cpu_buffer {
 739         struct mutex mutex;
 740         void *buf;
 741 };
 742 static struct uprobe_cpu_buffer __percpu *uprobe_cpu_buffer;
 743 static int uprobe_buffer_refcnt;
 744
 745 static int uprobe_buffer_init(void)
 746 {
 747         int cpu, err_cpu;
 748
 749         uprobe_cpu_buffer = alloc_percpu(struct uprobe_cpu_buffer);
 750         if (uprobe_cpu_buffer == NULL)
 751                 return -ENOMEM;
 752
 753         for_each_possible_cpu(cpu) {
 754                 struct page *p = alloc_pages_node(cpu_to_node(cpu),
 755                                                   GFP_KERNEL, 0);
 756                 if (p == NULL) {
 757                         err_cpu = cpu;
 758                         goto err;
 759                 }
 760                 per_cpu_ptr(uprobe_cpu_buffer, cpu)->buf = page_address(p);
 761                 mutex_init(&per_cpu_ptr(uprobe_cpu_buffer, cpu)->mutex);
 762         }
 763
 764         return 0;
 765
 766 err:
 767         for_each_possible_cpu(cpu) {
 768                 if (cpu == err_cpu)
 769                         break;
 770                 free_page((unsigned long)per_cpu_ptr(uprobe_cpu_buffer, cpu)->buf);
 771         }
 772
 773         free_percpu(uprobe_cpu_buffer);
 774         return -ENOMEM;
 775 }
 776
 777 static int uprobe_buffer_enable(void)
 778 {
 779         int ret = 0;
 780
 781         BUG_ON(!mutex_is_locked(&event_mutex));
 782
 783         if (uprobe_buffer_refcnt++ == 0) {
 784                 ret = uprobe_buffer_init();
 785                 if (ret < 0)
 786                         uprobe_buffer_refcnt--;
 787         }
 788
 789         return ret;
 790 }
 791
 792 static void uprobe_buffer_disable(void)
 793 {
 794         int cpu;
 795
 796         BUG_ON(!mutex_is_locked(&event_mutex));
 797
 798         if (--uprobe_buffer_refcnt == 0) {
 799                 for_each_possible_cpu(cpu)
 800                         free_page((unsigned long)per_cpu_ptr(uprobe_cpu_buffer,
 801                                                              cpu)->buf);
 802
 803                 free_percpu(uprobe_cpu_buffer);
 804                 uprobe_cpu_buffer = NULL;
 805         }
 806 }
 807
 808 static struct uprobe_cpu_buffer *uprobe_buffer_get(void)
 809 {
 810         struct uprobe_cpu_buffer *ucb;
 811         int cpu;
 812
 813         cpu = raw_smp_processor_id();
 814         ucb = per_cpu_ptr(uprobe_cpu_buffer, cpu);
 815
 816         /*
 817          * Use per-cpu buffers for fastest access, but we might migrate
 818          * so the mutex makes sure we have sole access to it.
 819          */
 820         mutex_lock(&ucb->mutex);
 821
 822         return ucb;
 823 }
 824
 825 static void uprobe_buffer_put(struct uprobe_cpu_buffer *ucb)
 826 {
 827         mutex_unlock(&ucb->mutex);
 828 }
 829
 830 static void __uprobe_trace_func(struct trace_uprobe *tu,
 831                                 unsigned long func, struct pt_regs *regs,
 832                                 struct uprobe_cpu_buffer *ucb, int dsize,
 833                                 struct trace_event_file *trace_file)
 834 {
 835         struct uprobe_trace_entry_head *entry;
 836         struct ring_buffer_event *event;
 837         struct ring_buffer *buffer;
 838         void *data;
 839         int size, esize;
 840         struct trace_event_call *call = &tu->tp.call;
 841
 842         WARN_ON(call != trace_file->event_call);
 843
 844         if (WARN_ON_ONCE(tu->tp.size + dsize > PAGE_SIZE))
 845                 return;
 846
 847         if (trace_trigger_soft_disabled(trace_file))
 848                 return;
 849
 850         esize = SIZEOF_TRACE_ENTRY(is_ret_probe(tu));
 851         size = esize + tu->tp.size + dsize;
 852         event = trace_event_buffer_lock_reserve(&buffer, trace_file,
 853                                                 call->event.type, size, 0, 0);
 854         if (!event)
 855                 return;
 856
 857         entry = ring_buffer_event_data(event);
 858         if (is_ret_probe(tu)) {
 859                 entry->vaddr[0] = func;
 860                 entry->vaddr[1] = instruction_pointer(regs);
 861                 data = DATAOF_TRACE_ENTRY(entry, true);
 862         } else {
 863                 entry->vaddr[0] = instruction_pointer(regs);
 864                 data = DATAOF_TRACE_ENTRY(entry, false);
 865         }
 866
 867         memcpy(data, ucb->buf, tu->tp.size + dsize);
 868
 869         event_trigger_unlock_commit(trace_file, buffer, event, entry, 0, 0);
 870 }
 871
 872 /* uprobe handler */
 873 static int uprobe_trace_func(struct trace_uprobe *tu, struct pt_regs *regs,
 874                              struct uprobe_cpu_buffer *ucb, int dsize)
 875 {
 876         struct event_file_link *link;
 877
 878         if (is_ret_probe(tu))
 879                 return 0;
 880
 881         rcu_read_lock();
 882         list_for_each_entry_rcu(link, &tu->tp.files, list)
 883                 __uprobe_trace_func(tu, 0, regs, ucb, dsize, link->file);
 884         rcu_read_unlock();
 885
 886         return 0;
 887 }
 888
 889 static void uretprobe_trace_func(struct trace_uprobe *tu, unsigned long func,
 890                                  struct pt_regs *regs,
 891                                  struct uprobe_cpu_buffer *ucb, int dsize)
 892 {
 893         struct event_file_link *link;
 894
 895         rcu_read_lock();
 896         list_for_each_entry_rcu(link, &tu->tp.files, list)
 897                 __uprobe_trace_func(tu, func, regs, ucb, dsize, link->file);
 898         rcu_read_unlock();
 899 }
 900
 901 /* Event entry printers */
 902 static enum print_line_t
 903 print_uprobe_event(struct trace_iterator *iter, int flags, struct trace_event *event)
 904 {
 905         struct uprobe_trace_entry_head *entry;
 906         struct trace_seq *s = &iter->seq;
 907         struct trace_uprobe *tu;
 908         u8 *data;
 909
 910         entry = (struct uprobe_trace_entry_head *)iter->ent;
 911         tu = container_of(event, struct trace_uprobe, tp.call.event);
 912
 913         if (is_ret_probe(tu)) {
 914                 trace_seq_printf(s, "%s: (0x%lx <- 0x%lx)",
 915                                  trace_event_name(&tu->tp.call),
 916                                  entry->vaddr[1], entry->vaddr[0]);
 917                 data = DATAOF_TRACE_ENTRY(entry, true);
 918         } else {
 919                 trace_seq_printf(s, "%s: (0x%lx)",
 920                                  trace_event_name(&tu->tp.call),
 921                                  entry->vaddr[0]);
 922                 data = DATAOF_TRACE_ENTRY(entry, false);
 923         }
 924
 925         if (print_probe_args(s, tu->tp.args, tu->tp.nr_args, data, entry) < 0)
 926                 goto out;
 927
 928         trace_seq_putc(s, '\n');
 929
 930  out:
 931         return trace_handle_return(s);
 932 }
 933
 934 typedef bool (*filter_func_t)(struct uprobe_consumer *self,
 935                                 enum uprobe_filter_ctx ctx,
 936                                 struct mm_struct *mm);
 937
 938 static int
 939 probe_event_enable(struct trace_uprobe *tu, struct trace_event_file *file,
 940                    filter_func_t filter)
 941 {
 942         bool enabled = trace_probe_is_enabled(&tu->tp);
 943         struct event_file_link *link = NULL;
 944         int ret;
 945
 946         if (file) {
 947                 if (tu->tp.flags & TP_FLAG_PROFILE)
 948                         return -EINTR;
 949
 950                 link = kmalloc(sizeof(*link), GFP_KERNEL);
 951                 if (!link)
 952                         return -ENOMEM;
 953
 954                 link->file = file;
 955                 list_add_tail_rcu(&link->list, &tu->tp.files);
 956
 957                 tu->tp.flags |= TP_FLAG_TRACE;
 958         } else {
 959                 if (tu->tp.flags & TP_FLAG_TRACE)
 960                         return -EINTR;
 961
 962                 tu->tp.flags |= TP_FLAG_PROFILE;
 963         }
 964
 965         WARN_ON(!uprobe_filter_is_empty(&tu->filter));
 966
 967         if (enabled)
 968                 return 0;
 969
 970         ret = uprobe_buffer_enable();
 971         if (ret)
 972                 goto err_flags;
 973
 974         tu->consumer.filter = filter;
 975         tu->inode = d_real_inode(tu->path.dentry);
 976         if (tu->ref_ctr_offset) {
 977                 ret = uprobe_register_refctr(tu->inode, tu->offset,
 978                                 tu->ref_ctr_offset, &tu->consumer);
 979         } else {
 980                 ret = uprobe_register(tu->inode, tu->offset, &tu->consumer);
 981         }
 982
 983         if (ret)
 984                 goto err_buffer;
 985
 986         return 0;
 987
 988  err_buffer:
 989         uprobe_buffer_disable();
 990
 991  err_flags:
 992         if (file) {
 993                 list_del(&link->list);
 994                 kfree(link);
 995                 tu->tp.flags &= ~TP_FLAG_TRACE;
 996         } else {
 997                 tu->tp.flags &= ~TP_FLAG_PROFILE;
 998         }
 999         return ret;
1000 }
1001
1002 static void
1003 probe_event_disable(struct trace_uprobe *tu, struct trace_event_file *file)
1004 {
1005         if (!trace_probe_is_enabled(&tu->tp))
1006                 return;
1007
1008         if (file) {
1009                 struct event_file_link *link;
1010
1011                 link = find_event_file_link(&tu->tp, file);
1012                 if (!link)
1013                         return;
1014
1015                 list_del_rcu(&link->list);
1016                 /* synchronize with u{,ret}probe_trace_func */
1017                 synchronize_rcu();
1018                 kfree(link);
1019
1020                 if (!list_empty(&tu->tp.files))
1021                         return;
1022         }
1023
1024         WARN_ON(!uprobe_filter_is_empty(&tu->filter));
1025
1026         uprobe_unregister(tu->inode, tu->offset, &tu->consumer);
1027         tu->inode = NULL;
1028         tu->tp.flags &= file ? ~TP_FLAG_TRACE : ~TP_FLAG_PROFILE;
1029
1030         uprobe_buffer_disable();
1031 }
1032
1033 static int uprobe_event_define_fields(struct trace_event_call *event_call)
1034 {
1035         int ret, size;
1036         struct uprobe_trace_entry_head field;
1037         struct trace_uprobe *tu = event_call->data;
1038
1039         if (is_ret_probe(tu)) {
1040                 DEFINE_FIELD(unsigned long, vaddr[0], FIELD_STRING_FUNC, 0);
1041                 DEFINE_FIELD(unsigned long, vaddr[1], FIELD_STRING_RETIP, 0);
1042                 size = SIZEOF_TRACE_ENTRY(true);
1043         } else {
1044                 DEFINE_FIELD(unsigned long, vaddr[0], FIELD_STRING_IP, 0);
1045                 size = SIZEOF_TRACE_ENTRY(false);
1046         }
1047
1048         return traceprobe_define_arg_fields(event_call, size, &tu->tp);
1049 }
1050
1051 #ifdef CONFIG_PERF_EVENTS
1052 static bool
1053 __uprobe_perf_filter(struct trace_uprobe_filter *filter, struct mm_struct *mm)
1054 {
1055         struct perf_event *event;
1056
1057         if (filter->nr_systemwide)
1058                 return true;
1059
1060         list_for_each_entry(event, &filter->perf_events, hw.tp_list) {
1061                 if (event->hw.target->mm == mm)
1062                         return true;
1063         }
1064
1065         return false;
1066 }
1067
1068 static inline bool
1069 uprobe_filter_event(struct trace_uprobe *tu, struct perf_event *event)
1070 {
1071         return __uprobe_perf_filter(&tu->filter, event->hw.target->mm);
1072 }
1073
1074 static int uprobe_perf_close(struct trace_uprobe *tu, struct perf_event *event)
1075 {
1076         bool done;
1077
1078         write_lock(&tu->filter.rwlock);
1079         if (event->hw.target) {
1080                 list_del(&event->hw.tp_list);
1081                 done = tu->filter.nr_systemwide ||
1082                         (event->hw.target->flags & PF_EXITING) ||
1083                         uprobe_filter_event(tu, event);
1084         } else {
1085                 tu->filter.nr_systemwide--;
1086                 done = tu->filter.nr_systemwide;
1087         }
1088         write_unlock(&tu->filter.rwlock);
1089
1090         if (!done)
1091                 return uprobe_apply(tu->inode, tu->offset, &tu->consumer, false);
1092
1093         return 0;
1094 }
1095
1096 static int uprobe_perf_open(struct trace_uprobe *tu, struct perf_event *event)
1097 {
1098         bool done;
1099         int err;
1100
1101         write_lock(&tu->filter.rwlock);
1102         if (event->hw.target) {
1103                 /*
1104                  * event->parent != NULL means copy_process(), we can avoid
1105                  * uprobe_apply(). current->mm must be probed and we can rely
1106                  * on dup_mmap() which preserves the already installed bp's.
1107                  *
1108                  * attr.enable_on_exec means that exec/mmap will install the
1109                  * breakpoints we need.
1110                  */
1111                 done = tu->filter.nr_systemwide ||
1112                         event->parent || event->attr.enable_on_exec ||
1113                         uprobe_filter_event(tu, event);
1114                 list_add(&event->hw.tp_list, &tu->filter.perf_events);
1115         } else {
1116                 done = tu->filter.nr_systemwide;
1117                 tu->filter.nr_systemwide++;
1118         }
1119         write_unlock(&tu->filter.rwlock);
1120
1121         err = 0;
1122         if (!done) {
1123                 err = uprobe_apply(tu->inode, tu->offset, &tu->consumer, true);
1124                 if (err)
1125                         uprobe_perf_close(tu, event);
1126         }
1127         return err;
1128 }
1129
1130 static bool uprobe_perf_filter(struct uprobe_consumer *uc,
1131                                 enum uprobe_filter_ctx ctx, struct mm_struct *mm)
1132 {
1133         struct trace_uprobe *tu;
1134         int ret;
1135
1136         tu = container_of(uc, struct trace_uprobe, consumer);
1137         read_lock(&tu->filter.rwlock);
1138         ret = __uprobe_perf_filter(&tu->filter, mm);
1139         read_unlock(&tu->filter.rwlock);
1140
1141         return ret;
1142 }
1143
1144 static void __uprobe_perf_func(struct trace_uprobe *tu,
1145                                unsigned long func, struct pt_regs *regs,
1146                                struct uprobe_cpu_buffer *ucb, int dsize)
1147 {
1148         struct trace_event_call *call = &tu->tp.call;
1149         struct uprobe_trace_entry_head *entry;
1150         struct hlist_head *head;
1151         void *data;
1152         int size, esize;
1153         int rctx;
1154
1155         if (bpf_prog_array_valid(call) && !trace_call_bpf(call, regs))
1156                 return;
1157
1158         esize = SIZEOF_TRACE_ENTRY(is_ret_probe(tu));
1159
1160         size = esize + tu->tp.size + dsize;
1161         size = ALIGN(size + sizeof(u32), sizeof(u64)) - sizeof(u32);
1162         if (WARN_ONCE(size > PERF_MAX_TRACE_SIZE, "profile buffer not large enough"))
1163                 return;
1164
1165         preempt_disable();
1166         head = this_cpu_ptr(call->perf_events);
1167         if (hlist_empty(head))
1168                 goto out;
1169
1170         entry = perf_trace_buf_alloc(size, NULL, &rctx);
1171         if (!entry)
1172                 goto out;
1173
1174         if (is_ret_probe(tu)) {
1175                 entry->vaddr[0] = func;
1176                 entry->vaddr[1] = instruction_pointer(regs);
1177                 data = DATAOF_TRACE_ENTRY(entry, true);
1178         } else {
1179                 entry->vaddr[0] = instruction_pointer(regs);
1180                 data = DATAOF_TRACE_ENTRY(entry, false);
1181         }
1182
1183         memcpy(data, ucb->buf, tu->tp.size + dsize);
1184
1185         if (size - esize > tu->tp.size + dsize) {
1186                 int len = tu->tp.size + dsize;
1187
1188                 memset(data + len, 0, size - esize - len);
1189         }
1190
1191         perf_trace_buf_submit(entry, size, rctx, call->event.type, 1, regs,
1192                               head, NULL);
1193  out:
1194         preempt_enable();
1195 }
1196
1197 /* uprobe profile handler */
1198 static int uprobe_perf_func(struct trace_uprobe *tu, struct pt_regs *regs,
1199                             struct uprobe_cpu_buffer *ucb, int dsize)
1200 {
1201         if (!uprobe_perf_filter(&tu->consumer, 0, current->mm))
1202                 return UPROBE_HANDLER_REMOVE;
1203
1204         if (!is_ret_probe(tu))
1205                 __uprobe_perf_func(tu, 0, regs, ucb, dsize);
1206         return 0;
1207 }
1208
1209 static void uretprobe_perf_func(struct trace_uprobe *tu, unsigned long func,
1210                                 struct pt_regs *regs,
1211                                 struct uprobe_cpu_buffer *ucb, int dsize)
1212 {
1213         __uprobe_perf_func(tu, func, regs, ucb, dsize);
1214 }
1215
1216 int bpf_get_uprobe_info(const struct perf_event *event, u32 *fd_type,
1217                         const char **filename, u64 *probe_offset,
1218                         bool perf_type_tracepoint)
1219 {
1220         const char *pevent = trace_event_name(event->tp_event);
1221         const char *group = event->tp_event->class->system;
1222         struct trace_uprobe *tu;
1223
1224         if (perf_type_tracepoint)
1225                 tu = find_probe_event(pevent, group);
1226         else
1227                 tu = event->tp_event->data;
1228         if (!tu)
1229                 return -EINVAL;
1230
1231         *fd_type = is_ret_probe(tu) ? BPF_FD_TYPE_URETPROBE
1232                                     : BPF_FD_TYPE_UPROBE;
1233         *filename = tu->filename;
1234         *probe_offset = tu->offset;
1235         return 0;
1236 }
1237 #endif  /* CONFIG_PERF_EVENTS */
1238
1239 static int
1240 trace_uprobe_register(struct trace_event_call *event, enum trace_reg type,
1241                       void *data)
1242 {
1243         struct trace_uprobe *tu = event->data;
1244         struct trace_event_file *file = data;
1245
1246         switch (type) {
1247         case TRACE_REG_REGISTER:
1248                 return probe_event_enable(tu, file, NULL);
1249
1250         case TRACE_REG_UNREGISTER:
1251                 probe_event_disable(tu, file);
1252                 return 0;
1253
1254 #ifdef CONFIG_PERF_EVENTS
1255         case TRACE_REG_PERF_REGISTER:
1256                 return probe_event_enable(tu, NULL, uprobe_perf_filter);
1257
1258         case TRACE_REG_PERF_UNREGISTER:
1259                 probe_event_disable(tu, NULL);
1260                 return 0;
1261
1262         case TRACE_REG_PERF_OPEN:
1263                 return uprobe_perf_open(tu, data);
1264
1265         case TRACE_REG_PERF_CLOSE:
1266                 return uprobe_perf_close(tu, data);
1267
1268 #endif
1269         default:
1270                 return 0;
1271         }
1272         return 0;
1273 }
1274
1275 static int uprobe_dispatcher(struct uprobe_consumer *con, struct pt_regs *regs)
1276 {
1277         struct trace_uprobe *tu;
1278         struct uprobe_dispatch_data udd;
1279         struct uprobe_cpu_buffer *ucb;
1280         int dsize, esize;
1281         int ret = 0;
1282
1283
1284         tu = container_of(con, struct trace_uprobe, consumer);
1285         tu->nhit++;
1286
1287         udd.tu = tu;
1288         udd.bp_addr = instruction_pointer(regs);
1289
1290         current->utask->vaddr = (unsigned long) &udd;
1291
1292         if (WARN_ON_ONCE(!uprobe_cpu_buffer))
1293                 return 0;
1294
1295         dsize = __get_data_size(&tu->tp, regs);
1296         esize = SIZEOF_TRACE_ENTRY(is_ret_probe(tu));
1297
1298         ucb = uprobe_buffer_get();
1299         store_trace_args(ucb->buf, &tu->tp, regs, esize, dsize);
1300
1301         if (tu->tp.flags & TP_FLAG_TRACE)
1302                 ret |= uprobe_trace_func(tu, regs, ucb, dsize);
1303
1304 #ifdef CONFIG_PERF_EVENTS
1305         if (tu->tp.flags & TP_FLAG_PROFILE)
1306                 ret |= uprobe_perf_func(tu, regs, ucb, dsize);
1307 #endif
1308         uprobe_buffer_put(ucb);
1309         return ret;
1310 }
1311
1312 static int uretprobe_dispatcher(struct uprobe_consumer *con,
1313                                 unsigned long func, struct pt_regs *regs)
1314 {
1315         struct trace_uprobe *tu;
1316         struct uprobe_dispatch_data udd;
1317         struct uprobe_cpu_buffer *ucb;
1318         int dsize, esize;
1319
1320         tu = container_of(con, struct trace_uprobe, consumer);
1321
1322         udd.tu = tu;
1323         udd.bp_addr = func;
1324
1325         current->utask->vaddr = (unsigned long) &udd;
1326
1327         if (WARN_ON_ONCE(!uprobe_cpu_buffer))
1328                 return 0;
1329
1330         dsize = __get_data_size(&tu->tp, regs);
1331         esize = SIZEOF_TRACE_ENTRY(is_ret_probe(tu));
1332
1333         ucb = uprobe_buffer_get();
1334         store_trace_args(ucb->buf, &tu->tp, regs, esize, dsize);
1335
1336         if (tu->tp.flags & TP_FLAG_TRACE)
1337                 uretprobe_trace_func(tu, func, regs, ucb, dsize);
1338
1339 #ifdef CONFIG_PERF_EVENTS
1340         if (tu->tp.flags & TP_FLAG_PROFILE)
1341                 uretprobe_perf_func(tu, func, regs, ucb, dsize);
1342 #endif
1343         uprobe_buffer_put(ucb);
1344         return 0;
1345 }
1346
1347 static struct trace_event_functions uprobe_funcs = {
1348         .trace          = print_uprobe_event
1349 };
1350
1351 static inline void init_trace_event_call(struct trace_uprobe *tu,
1352                                          struct trace_event_call *call)
1353 {
1354         INIT_LIST_HEAD(&call->class->fields);
1355         call->event.funcs = &uprobe_funcs;
1356         call->class->define_fields = uprobe_event_define_fields;
1357
1358         call->flags = TRACE_EVENT_FL_UPROBE;
1359         call->class->reg = trace_uprobe_register;
1360         call->data = tu;
1361 }
1362
1363 static int register_uprobe_event(struct trace_uprobe *tu)
1364 {
1365         struct trace_event_call *call = &tu->tp.call;
1366         int ret = 0;
1367
1368         init_trace_event_call(tu, call);
1369
1370         ret = register_trace_event(&call->event);
1371         if (!ret)
1372                 return -ENODEV;
1373
1374         ret = trace_add_event_call(call);
1375
1376         if (ret) {
1377                 pr_info("Failed to register uprobe event: %s\n",
1378                         trace_event_name(call));
1379                 unregister_trace_event(&call->event);
1380         }
1381
1382         return ret;
1383 }
1384
1385 static int unregister_uprobe_event(struct trace_uprobe *tu)
1386 {
1387         /* tu->event is unregistered in trace_remove_event_call() */
1388         return trace_remove_event_call(&tu->tp.call);
1389 }
1390
1391 #ifdef CONFIG_PERF_EVENTS
1392 struct trace_event_call *
1393 create_local_trace_uprobe(char *name, unsigned long offs,
1394                           unsigned long ref_ctr_offset, bool is_return)
1395 {
1396         struct trace_uprobe *tu;
1397         struct path path;
1398         int ret;
1399
1400         ret = kern_path(name, LOOKUP_FOLLOW, &path);
1401         if (ret)
1402                 return ERR_PTR(ret);
1403
1404         if (!d_is_reg(path.dentry)) {
1405                 path_put(&path);
1406                 return ERR_PTR(-EINVAL);
1407         }
1408
1409         /*
1410          * local trace_kprobes are not added to dyn_event, so they are never
1411          * searched in find_trace_kprobe(). Therefore, there is no concern of
1412          * duplicated name "DUMMY_EVENT" here.
1413          */
1414         tu = alloc_trace_uprobe(UPROBE_EVENT_SYSTEM, "DUMMY_EVENT", 0,
1415                                 is_return);
1416
1417         if (IS_ERR(tu)) {
1418                 pr_info("Failed to allocate trace_uprobe.(%d)\n",
1419                         (int)PTR_ERR(tu));
1420                 path_put(&path);
1421                 return ERR_CAST(tu);
1422         }
1423
1424         tu->offset = offs;
1425         tu->path = path;
1426         tu->ref_ctr_offset = ref_ctr_offset;
1427         tu->filename = kstrdup(name, GFP_KERNEL);
1428         init_trace_event_call(tu, &tu->tp.call);
1429
1430         if (traceprobe_set_print_fmt(&tu->tp, is_ret_probe(tu)) < 0) {
1431                 ret = -ENOMEM;
1432                 goto error;
1433         }
1434
1435         return &tu->tp.call;
1436 error:
1437         free_trace_uprobe(tu);
1438         return ERR_PTR(ret);
1439 }
1440
1441 void destroy_local_trace_uprobe(struct trace_event_call *event_call)
1442 {
1443         struct trace_uprobe *tu;
1444
1445         tu = container_of(event_call, struct trace_uprobe, tp.call);
1446
1447         free_trace_uprobe(tu);
1448 }
1449 #endif /* CONFIG_PERF_EVENTS */
1450
1451 /* Make a trace interface for controling probe points */
1452 static __init int init_uprobe_trace(void)
1453 {
1454         struct dentry *d_tracer;
1455         int ret;
1456
1457         ret = dyn_event_register(&trace_uprobe_ops);
1458         if (ret)
1459                 return ret;
1460
1461         d_tracer = tracing_init_dentry();
1462         if (IS_ERR(d_tracer))
1463                 return 0;
1464
1465         trace_create_file("uprobe_events", 0644, d_tracer,
1466                                     NULL, &uprobe_events_ops);
1467         /* Profile interface */
1468         trace_create_file("uprobe_profile", 0444, d_tracer,
1469                                     NULL, &uprobe_profile_ops);
1470         return 0;
1471 }
1472
1473 fs_initcall(init_uprobe_trace);