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