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