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  *  - Remove uprobe: -:[GRP/]EVENT
 431  */
 432 static int trace_uprobe_create(int argc, const char **argv)
 433 {
 434         struct trace_uprobe *tu;
 435         const char *event = NULL, *group = UPROBE_EVENT_SYSTEM;
 436         char *arg, *filename, *rctr, *rctr_end, *tmp;
 437         char buf[MAX_EVENT_NAME_LEN];
 438         struct path path;
 439         unsigned long offset, ref_ctr_offset;
 440         bool is_return = false;
 441         int i, ret;
 442
 443         ret = 0;
 444         ref_ctr_offset = 0;
 445
 446         /* argc must be >= 1 */
 447         if (argv[0][0] == 'r')
 448                 is_return = true;
 449         else if (argv[0][0] != 'p' || argc < 2)
 450                 return -ECANCELED;
 451
 452         if (argv[0][1] == ':')
 453                 event = &argv[0][2];
 454
 455         if (!strchr(argv[1], '/'))
 456                 return -ECANCELED;
 457
 458         filename = kstrdup(argv[1], GFP_KERNEL);
 459         if (!filename)
 460                 return -ENOMEM;
 461
 462         /* Find the last occurrence, in case the path contains ':' too. */
 463         arg = strrchr(filename, ':');
 464         if (!arg || !isdigit(arg[1])) {
 465                 kfree(filename);
 466                 return -ECANCELED;
 467         }
 468
 469         trace_probe_log_init("trace_uprobe", argc, argv);
 470         trace_probe_log_set_index(1);   /* filename is the 2nd argument */
 471
 472         *arg++ = '\0';
 473         ret = kern_path(filename, LOOKUP_FOLLOW, &path);
 474         if (ret) {
 475                 trace_probe_log_err(0, FILE_NOT_FOUND);
 476                 kfree(filename);
 477                 trace_probe_log_clear();
 478                 return ret;
 479         }
 480         if (!d_is_reg(path.dentry)) {
 481                 trace_probe_log_err(0, NO_REGULAR_FILE);
 482                 ret = -EINVAL;
 483                 goto fail_address_parse;
 484         }
 485
 486         /* Parse reference counter offset if specified. */
 487         rctr = strchr(arg, '(');
 488         if (rctr) {
 489                 rctr_end = strchr(rctr, ')');
 490                 if (!rctr_end) {
 491                         ret = -EINVAL;
 492                         rctr_end = rctr + strlen(rctr);
 493                         trace_probe_log_err(rctr_end - filename,
 494                                             REFCNT_OPEN_BRACE);
 495                         goto fail_address_parse;
 496                 } else if (rctr_end[1] != '\0') {
 497                         ret = -EINVAL;
 498                         trace_probe_log_err(rctr_end + 1 - filename,
 499                                             BAD_REFCNT_SUFFIX);
 500                         goto fail_address_parse;
 501                 }
 502
 503                 *rctr++ = '\0';
 504                 *rctr_end = '\0';
 505                 ret = kstrtoul(rctr, 0, &ref_ctr_offset);
 506                 if (ret) {
 507                         trace_probe_log_err(rctr - filename, BAD_REFCNT);
 508                         goto fail_address_parse;
 509                 }
 510         }
 511
 512         /* Parse uprobe offset. */
 513         ret = kstrtoul(arg, 0, &offset);
 514         if (ret) {
 515                 trace_probe_log_err(arg - filename, BAD_UPROBE_OFFS);
 516                 goto fail_address_parse;
 517         }
 518
 519         /* setup a probe */
 520         trace_probe_log_set_index(0);
 521         if (event) {
 522                 ret = traceprobe_parse_event_name(&event, &group, buf,
 523                                                   event - argv[0]);
 524                 if (ret)
 525                         goto fail_address_parse;
 526         } else {
 527                 char *tail;
 528                 char *ptr;
 529
 530                 tail = kstrdup(kbasename(filename), GFP_KERNEL);
 531                 if (!tail) {
 532                         ret = -ENOMEM;
 533                         goto fail_address_parse;
 534                 }
 535
 536                 ptr = strpbrk(tail, ".-_");
 537                 if (ptr)
 538                         *ptr = '\0';
 539
 540                 snprintf(buf, MAX_EVENT_NAME_LEN, "%c_%s_0x%lx", 'p', tail, offset);
 541                 event = buf;
 542                 kfree(tail);
 543         }
 544
 545         argc -= 2;
 546         argv += 2;
 547
 548         tu = alloc_trace_uprobe(group, event, argc, is_return);
 549         if (IS_ERR(tu)) {
 550                 ret = PTR_ERR(tu);
 551                 /* This must return -ENOMEM otherwise there is a bug */
 552                 WARN_ON_ONCE(ret != -ENOMEM);
 553                 goto fail_address_parse;
 554         }
 555         tu->offset = offset;
 556         tu->ref_ctr_offset = ref_ctr_offset;
 557         tu->path = path;
 558         tu->filename = filename;
 559
 560         /* parse arguments */
 561         for (i = 0; i < argc && i < MAX_TRACE_ARGS; i++) {
 562                 tmp = kstrdup(argv[i], GFP_KERNEL);
 563                 if (!tmp) {
 564                         ret = -ENOMEM;
 565                         goto error;
 566                 }
 567
 568                 trace_probe_log_set_index(i + 2);
 569                 ret = traceprobe_parse_probe_arg(&tu->tp, i, tmp,
 570                                         is_return ? TPARG_FL_RETURN : 0);
 571                 kfree(tmp);
 572                 if (ret)
 573                         goto error;
 574         }
 575
 576         ret = register_trace_uprobe(tu);
 577         if (!ret)
 578                 goto out;
 579
 580 error:
 581         free_trace_uprobe(tu);
 582 out:
 583         trace_probe_log_clear();
 584         return ret;
 585
 586 fail_address_parse:
 587         trace_probe_log_clear();
 588         path_put(&path);
 589         kfree(filename);
 590
 591         return ret;
 592 }
 593
 594 static int create_or_delete_trace_uprobe(int argc, char **argv)
 595 {
 596         int ret;
 597
 598         if (argv[0][0] == '-')
 599                 return dyn_event_release(argc, argv, &trace_uprobe_ops);
 600
 601         ret = trace_uprobe_create(argc, (const char **)argv);
 602         return ret == -ECANCELED ? -EINVAL : ret;
 603 }
 604
 605 static int trace_uprobe_release(struct dyn_event *ev)
 606 {
 607         struct trace_uprobe *tu = to_trace_uprobe(ev);
 608
 609         return unregister_trace_uprobe(tu);
 610 }
 611
 612 /* Probes listing interfaces */
 613 static int trace_uprobe_show(struct seq_file *m, struct dyn_event *ev)
 614 {
 615         struct trace_uprobe *tu = to_trace_uprobe(ev);
 616         char c = is_ret_probe(tu) ? 'r' : 'p';
 617         int i;
 618
 619         seq_printf(m, "%c:%s/%s %s:0x%0*lx", c, tu->tp.call.class->system,
 620                         trace_event_name(&tu->tp.call), tu->filename,
 621                         (int)(sizeof(void *) * 2), tu->offset);
 622
 623         if (tu->ref_ctr_offset)
 624                 seq_printf(m, "(0x%lx)", tu->ref_ctr_offset);
 625
 626         for (i = 0; i < tu->tp.nr_args; i++)
 627                 seq_printf(m, " %s=%s", tu->tp.args[i].name, tu->tp.args[i].comm);
 628
 629         seq_putc(m, '\n');
 630         return 0;
 631 }
 632
 633 static int probes_seq_show(struct seq_file *m, void *v)
 634 {
 635         struct dyn_event *ev = v;
 636
 637         if (!is_trace_uprobe(ev))
 638                 return 0;
 639
 640         return trace_uprobe_show(m, ev);
 641 }
 642
 643 static const struct seq_operations probes_seq_op = {
 644         .start  = dyn_event_seq_start,
 645         .next   = dyn_event_seq_next,
 646         .stop   = dyn_event_seq_stop,
 647         .show   = probes_seq_show
 648 };
 649
 650 static int probes_open(struct inode *inode, struct file *file)
 651 {
 652         int ret;
 653
 654         if ((file->f_mode & FMODE_WRITE) && (file->f_flags & O_TRUNC)) {
 655                 ret = dyn_events_release_all(&trace_uprobe_ops);
 656                 if (ret)
 657                         return ret;
 658         }
 659
 660         return seq_open(file, &probes_seq_op);
 661 }
 662
 663 static ssize_t probes_write(struct file *file, const char __user *buffer,
 664                             size_t count, loff_t *ppos)
 665 {
 666         return trace_parse_run_command(file, buffer, count, ppos,
 667                                         create_or_delete_trace_uprobe);
 668 }
 669
 670 static const struct file_operations uprobe_events_ops = {
 671         .owner          = THIS_MODULE,
 672         .open           = probes_open,
 673         .read           = seq_read,
 674         .llseek         = seq_lseek,
 675         .release        = seq_release,
 676         .write          = probes_write,
 677 };
 678
 679 /* Probes profiling interfaces */
 680 static int probes_profile_seq_show(struct seq_file *m, void *v)
 681 {
 682         struct dyn_event *ev = v;
 683         struct trace_uprobe *tu;
 684
 685         if (!is_trace_uprobe(ev))
 686                 return 0;
 687
 688         tu = to_trace_uprobe(ev);
 689         seq_printf(m, "  %s %-44s %15lu\n", tu->filename,
 690                         trace_event_name(&tu->tp.call), tu->nhit);
 691         return 0;
 692 }
 693
 694 static const struct seq_operations profile_seq_op = {
 695         .start  = dyn_event_seq_start,
 696         .next   = dyn_event_seq_next,
 697         .stop   = dyn_event_seq_stop,
 698         .show   = probes_profile_seq_show
 699 };
 700
 701 static int profile_open(struct inode *inode, struct file *file)
 702 {
 703         return seq_open(file, &profile_seq_op);
 704 }
 705
 706 static const struct file_operations uprobe_profile_ops = {
 707         .owner          = THIS_MODULE,
 708         .open           = profile_open,
 709         .read           = seq_read,
 710         .llseek         = seq_lseek,
 711         .release        = seq_release,
 712 };
 713
 714 struct uprobe_cpu_buffer {
 715         struct mutex mutex;
 716         void *buf;
 717 };
 718 static struct uprobe_cpu_buffer __percpu *uprobe_cpu_buffer;
 719 static int uprobe_buffer_refcnt;
 720
 721 static int uprobe_buffer_init(void)
 722 {
 723         int cpu, err_cpu;
 724
 725         uprobe_cpu_buffer = alloc_percpu(struct uprobe_cpu_buffer);
 726         if (uprobe_cpu_buffer == NULL)
 727                 return -ENOMEM;
 728
 729         for_each_possible_cpu(cpu) {
 730                 struct page *p = alloc_pages_node(cpu_to_node(cpu),
 731                                                   GFP_KERNEL, 0);
 732                 if (p == NULL) {
 733                         err_cpu = cpu;
 734                         goto err;
 735                 }
 736                 per_cpu_ptr(uprobe_cpu_buffer, cpu)->buf = page_address(p);
 737                 mutex_init(&per_cpu_ptr(uprobe_cpu_buffer, cpu)->mutex);
 738         }
 739
 740         return 0;
 741
 742 err:
 743         for_each_possible_cpu(cpu) {
 744                 if (cpu == err_cpu)
 745                         break;
 746                 free_page((unsigned long)per_cpu_ptr(uprobe_cpu_buffer, cpu)->buf);
 747         }
 748
 749         free_percpu(uprobe_cpu_buffer);
 750         return -ENOMEM;
 751 }
 752
 753 static int uprobe_buffer_enable(void)
 754 {
 755         int ret = 0;
 756
 757         BUG_ON(!mutex_is_locked(&event_mutex));
 758
 759         if (uprobe_buffer_refcnt++ == 0) {
 760                 ret = uprobe_buffer_init();
 761                 if (ret < 0)
 762                         uprobe_buffer_refcnt--;
 763         }
 764
 765         return ret;
 766 }
 767
 768 static void uprobe_buffer_disable(void)
 769 {
 770         int cpu;
 771
 772         BUG_ON(!mutex_is_locked(&event_mutex));
 773
 774         if (--uprobe_buffer_refcnt == 0) {
 775                 for_each_possible_cpu(cpu)
 776                         free_page((unsigned long)per_cpu_ptr(uprobe_cpu_buffer,
 777                                                              cpu)->buf);
 778
 779                 free_percpu(uprobe_cpu_buffer);
 780                 uprobe_cpu_buffer = NULL;
 781         }
 782 }
 783
 784 static struct uprobe_cpu_buffer *uprobe_buffer_get(void)
 785 {
 786         struct uprobe_cpu_buffer *ucb;
 787         int cpu;
 788
 789         cpu = raw_smp_processor_id();
 790         ucb = per_cpu_ptr(uprobe_cpu_buffer, cpu);
 791
 792         /*
 793          * Use per-cpu buffers for fastest access, but we might migrate
 794          * so the mutex makes sure we have sole access to it.
 795          */
 796         mutex_lock(&ucb->mutex);
 797
 798         return ucb;
 799 }
 800
 801 static void uprobe_buffer_put(struct uprobe_cpu_buffer *ucb)
 802 {
 803         mutex_unlock(&ucb->mutex);
 804 }
 805
 806 static void __uprobe_trace_func(struct trace_uprobe *tu,
 807                                 unsigned long func, struct pt_regs *regs,
 808                                 struct uprobe_cpu_buffer *ucb, int dsize,
 809                                 struct trace_event_file *trace_file)
 810 {
 811         struct uprobe_trace_entry_head *entry;
 812         struct ring_buffer_event *event;
 813         struct ring_buffer *buffer;
 814         void *data;
 815         int size, esize;
 816         struct trace_event_call *call = &tu->tp.call;
 817
 818         WARN_ON(call != trace_file->event_call);
 819
 820         if (WARN_ON_ONCE(tu->tp.size + dsize > PAGE_SIZE))
 821                 return;
 822
 823         if (trace_trigger_soft_disabled(trace_file))
 824                 return;
 825
 826         esize = SIZEOF_TRACE_ENTRY(is_ret_probe(tu));
 827         size = esize + tu->tp.size + dsize;
 828         event = trace_event_buffer_lock_reserve(&buffer, trace_file,
 829                                                 call->event.type, size, 0, 0);
 830         if (!event)
 831                 return;
 832
 833         entry = ring_buffer_event_data(event);
 834         if (is_ret_probe(tu)) {
 835                 entry->vaddr[0] = func;
 836                 entry->vaddr[1] = instruction_pointer(regs);
 837                 data = DATAOF_TRACE_ENTRY(entry, true);
 838         } else {
 839                 entry->vaddr[0] = instruction_pointer(regs);
 840                 data = DATAOF_TRACE_ENTRY(entry, false);
 841         }
 842
 843         memcpy(data, ucb->buf, tu->tp.size + dsize);
 844
 845         event_trigger_unlock_commit(trace_file, buffer, event, entry, 0, 0);
 846 }
 847
 848 /* uprobe handler */
 849 static int uprobe_trace_func(struct trace_uprobe *tu, struct pt_regs *regs,
 850                              struct uprobe_cpu_buffer *ucb, int dsize)
 851 {
 852         struct event_file_link *link;
 853
 854         if (is_ret_probe(tu))
 855                 return 0;
 856
 857         rcu_read_lock();
 858         list_for_each_entry_rcu(link, &tu->tp.files, list)
 859                 __uprobe_trace_func(tu, 0, regs, ucb, dsize, link->file);
 860         rcu_read_unlock();
 861
 862         return 0;
 863 }
 864
 865 static void uretprobe_trace_func(struct trace_uprobe *tu, unsigned long func,
 866                                  struct pt_regs *regs,
 867                                  struct uprobe_cpu_buffer *ucb, int dsize)
 868 {
 869         struct event_file_link *link;
 870
 871         rcu_read_lock();
 872         list_for_each_entry_rcu(link, &tu->tp.files, list)
 873                 __uprobe_trace_func(tu, func, regs, ucb, dsize, link->file);
 874         rcu_read_unlock();
 875 }
 876
 877 /* Event entry printers */
 878 static enum print_line_t
 879 print_uprobe_event(struct trace_iterator *iter, int flags, struct trace_event *event)
 880 {
 881         struct uprobe_trace_entry_head *entry;
 882         struct trace_seq *s = &iter->seq;
 883         struct trace_uprobe *tu;
 884         u8 *data;
 885
 886         entry = (struct uprobe_trace_entry_head *)iter->ent;
 887         tu = container_of(event, struct trace_uprobe, tp.call.event);
 888
 889         if (is_ret_probe(tu)) {
 890                 trace_seq_printf(s, "%s: (0x%lx <- 0x%lx)",
 891                                  trace_event_name(&tu->tp.call),
 892                                  entry->vaddr[1], entry->vaddr[0]);
 893                 data = DATAOF_TRACE_ENTRY(entry, true);
 894         } else {
 895                 trace_seq_printf(s, "%s: (0x%lx)",
 896                                  trace_event_name(&tu->tp.call),
 897                                  entry->vaddr[0]);
 898                 data = DATAOF_TRACE_ENTRY(entry, false);
 899         }
 900
 901         if (print_probe_args(s, tu->tp.args, tu->tp.nr_args, data, entry) < 0)
 902                 goto out;
 903
 904         trace_seq_putc(s, '\n');
 905
 906  out:
 907         return trace_handle_return(s);
 908 }
 909
 910 typedef bool (*filter_func_t)(struct uprobe_consumer *self,
 911                                 enum uprobe_filter_ctx ctx,
 912                                 struct mm_struct *mm);
 913
 914 static int
 915 probe_event_enable(struct trace_uprobe *tu, struct trace_event_file *file,
 916                    filter_func_t filter)
 917 {
 918         bool enabled = trace_probe_is_enabled(&tu->tp);
 919         struct event_file_link *link = NULL;
 920         int ret;
 921
 922         if (file) {
 923                 if (tu->tp.flags & TP_FLAG_PROFILE)
 924                         return -EINTR;
 925
 926                 link = kmalloc(sizeof(*link), GFP_KERNEL);
 927                 if (!link)
 928                         return -ENOMEM;
 929
 930                 link->file = file;
 931                 list_add_tail_rcu(&link->list, &tu->tp.files);
 932
 933                 tu->tp.flags |= TP_FLAG_TRACE;
 934         } else {
 935                 if (tu->tp.flags & TP_FLAG_TRACE)
 936                         return -EINTR;
 937
 938                 tu->tp.flags |= TP_FLAG_PROFILE;
 939         }
 940
 941         WARN_ON(!uprobe_filter_is_empty(&tu->filter));
 942
 943         if (enabled)
 944                 return 0;
 945
 946         ret = uprobe_buffer_enable();
 947         if (ret)
 948                 goto err_flags;
 949
 950         tu->consumer.filter = filter;
 951         tu->inode = d_real_inode(tu->path.dentry);
 952         if (tu->ref_ctr_offset) {
 953                 ret = uprobe_register_refctr(tu->inode, tu->offset,
 954                                 tu->ref_ctr_offset, &tu->consumer);
 955         } else {
 956                 ret = uprobe_register(tu->inode, tu->offset, &tu->consumer);
 957         }
 958
 959         if (ret)
 960                 goto err_buffer;
 961
 962         return 0;
 963
 964  err_buffer:
 965         uprobe_buffer_disable();
 966
 967  err_flags:
 968         if (file) {
 969                 list_del(&link->list);
 970                 kfree(link);
 971                 tu->tp.flags &= ~TP_FLAG_TRACE;
 972         } else {
 973                 tu->tp.flags &= ~TP_FLAG_PROFILE;
 974         }
 975         return ret;
 976 }
 977
 978 static void
 979 probe_event_disable(struct trace_uprobe *tu, struct trace_event_file *file)
 980 {
 981         if (!trace_probe_is_enabled(&tu->tp))
 982                 return;
 983
 984         if (file) {
 985                 struct event_file_link *link;
 986
 987                 link = find_event_file_link(&tu->tp, file);
 988                 if (!link)
 989                         return;
 990
 991                 list_del_rcu(&link->list);
 992                 /* synchronize with u{,ret}probe_trace_func */
 993                 synchronize_rcu();
 994                 kfree(link);
 995
 996                 if (!list_empty(&tu->tp.files))
 997                         return;
 998         }
 999
1000         WARN_ON(!uprobe_filter_is_empty(&tu->filter));
1001
1002         uprobe_unregister(tu->inode, tu->offset, &tu->consumer);
1003         tu->inode = NULL;
1004         tu->tp.flags &= file ? ~TP_FLAG_TRACE : ~TP_FLAG_PROFILE;
1005
1006         uprobe_buffer_disable();
1007 }
1008
1009 static int uprobe_event_define_fields(struct trace_event_call *event_call)
1010 {
1011         int ret, size;
1012         struct uprobe_trace_entry_head field;
1013         struct trace_uprobe *tu = event_call->data;
1014
1015         if (is_ret_probe(tu)) {
1016                 DEFINE_FIELD(unsigned long, vaddr[0], FIELD_STRING_FUNC, 0);
1017                 DEFINE_FIELD(unsigned long, vaddr[1], FIELD_STRING_RETIP, 0);
1018                 size = SIZEOF_TRACE_ENTRY(true);
1019         } else {
1020                 DEFINE_FIELD(unsigned long, vaddr[0], FIELD_STRING_IP, 0);
1021                 size = SIZEOF_TRACE_ENTRY(false);
1022         }
1023
1024         return traceprobe_define_arg_fields(event_call, size, &tu->tp);
1025 }
1026
1027 #ifdef CONFIG_PERF_EVENTS
1028 static bool
1029 __uprobe_perf_filter(struct trace_uprobe_filter *filter, struct mm_struct *mm)
1030 {
1031         struct perf_event *event;
1032
1033         if (filter->nr_systemwide)
1034                 return true;
1035
1036         list_for_each_entry(event, &filter->perf_events, hw.tp_list) {
1037                 if (event->hw.target->mm == mm)
1038                         return true;
1039         }
1040
1041         return false;
1042 }
1043
1044 static inline bool
1045 uprobe_filter_event(struct trace_uprobe *tu, struct perf_event *event)
1046 {
1047         return __uprobe_perf_filter(&tu->filter, event->hw.target->mm);
1048 }
1049
1050 static int uprobe_perf_close(struct trace_uprobe *tu, struct perf_event *event)
1051 {
1052         bool done;
1053
1054         write_lock(&tu->filter.rwlock);
1055         if (event->hw.target) {
1056                 list_del(&event->hw.tp_list);
1057                 done = tu->filter.nr_systemwide ||
1058                         (event->hw.target->flags & PF_EXITING) ||
1059                         uprobe_filter_event(tu, event);
1060         } else {
1061                 tu->filter.nr_systemwide--;
1062                 done = tu->filter.nr_systemwide;
1063         }
1064         write_unlock(&tu->filter.rwlock);
1065
1066         if (!done)
1067                 return uprobe_apply(tu->inode, tu->offset, &tu->consumer, false);
1068
1069         return 0;
1070 }
1071
1072 static int uprobe_perf_open(struct trace_uprobe *tu, struct perf_event *event)
1073 {
1074         bool done;
1075         int err;
1076
1077         write_lock(&tu->filter.rwlock);
1078         if (event->hw.target) {
1079                 /*
1080                  * event->parent != NULL means copy_process(), we can avoid
1081                  * uprobe_apply(). current->mm must be probed and we can rely
1082                  * on dup_mmap() which preserves the already installed bp's.
1083                  *
1084                  * attr.enable_on_exec means that exec/mmap will install the
1085                  * breakpoints we need.
1086                  */
1087                 done = tu->filter.nr_systemwide ||
1088                         event->parent || event->attr.enable_on_exec ||
1089                         uprobe_filter_event(tu, event);
1090                 list_add(&event->hw.tp_list, &tu->filter.perf_events);
1091         } else {
1092                 done = tu->filter.nr_systemwide;
1093                 tu->filter.nr_systemwide++;
1094         }
1095         write_unlock(&tu->filter.rwlock);
1096
1097         err = 0;
1098         if (!done) {
1099                 err = uprobe_apply(tu->inode, tu->offset, &tu->consumer, true);
1100                 if (err)
1101                         uprobe_perf_close(tu, event);
1102         }
1103         return err;
1104 }
1105
1106 static bool uprobe_perf_filter(struct uprobe_consumer *uc,
1107                                 enum uprobe_filter_ctx ctx, struct mm_struct *mm)
1108 {
1109         struct trace_uprobe *tu;
1110         int ret;
1111
1112         tu = container_of(uc, struct trace_uprobe, consumer);
1113         read_lock(&tu->filter.rwlock);
1114         ret = __uprobe_perf_filter(&tu->filter, mm);
1115         read_unlock(&tu->filter.rwlock);
1116
1117         return ret;
1118 }
1119
1120 static void __uprobe_perf_func(struct trace_uprobe *tu,
1121                                unsigned long func, struct pt_regs *regs,
1122                                struct uprobe_cpu_buffer *ucb, int dsize)
1123 {
1124         struct trace_event_call *call = &tu->tp.call;
1125         struct uprobe_trace_entry_head *entry;
1126         struct hlist_head *head;
1127         void *data;
1128         int size, esize;
1129         int rctx;
1130
1131         if (bpf_prog_array_valid(call) && !trace_call_bpf(call, regs))
1132                 return;
1133
1134         esize = SIZEOF_TRACE_ENTRY(is_ret_probe(tu));
1135
1136         size = esize + tu->tp.size + dsize;
1137         size = ALIGN(size + sizeof(u32), sizeof(u64)) - sizeof(u32);
1138         if (WARN_ONCE(size > PERF_MAX_TRACE_SIZE, "profile buffer not large enough"))
1139                 return;
1140
1141         preempt_disable();
1142         head = this_cpu_ptr(call->perf_events);
1143         if (hlist_empty(head))
1144                 goto out;
1145
1146         entry = perf_trace_buf_alloc(size, NULL, &rctx);
1147         if (!entry)
1148                 goto out;
1149
1150         if (is_ret_probe(tu)) {
1151                 entry->vaddr[0] = func;
1152                 entry->vaddr[1] = instruction_pointer(regs);
1153                 data = DATAOF_TRACE_ENTRY(entry, true);
1154         } else {
1155                 entry->vaddr[0] = instruction_pointer(regs);
1156                 data = DATAOF_TRACE_ENTRY(entry, false);
1157         }
1158
1159         memcpy(data, ucb->buf, tu->tp.size + dsize);
1160
1161         if (size - esize > tu->tp.size + dsize) {
1162                 int len = tu->tp.size + dsize;
1163
1164                 memset(data + len, 0, size - esize - len);
1165         }
1166
1167         perf_trace_buf_submit(entry, size, rctx, call->event.type, 1, regs,
1168                               head, NULL);
1169  out:
1170         preempt_enable();
1171 }
1172
1173 /* uprobe profile handler */
1174 static int uprobe_perf_func(struct trace_uprobe *tu, struct pt_regs *regs,
1175                             struct uprobe_cpu_buffer *ucb, int dsize)
1176 {
1177         if (!uprobe_perf_filter(&tu->consumer, 0, current->mm))
1178                 return UPROBE_HANDLER_REMOVE;
1179
1180         if (!is_ret_probe(tu))
1181                 __uprobe_perf_func(tu, 0, regs, ucb, dsize);
1182         return 0;
1183 }
1184
1185 static void uretprobe_perf_func(struct trace_uprobe *tu, unsigned long func,
1186                                 struct pt_regs *regs,
1187                                 struct uprobe_cpu_buffer *ucb, int dsize)
1188 {
1189         __uprobe_perf_func(tu, func, regs, ucb, dsize);
1190 }
1191
1192 int bpf_get_uprobe_info(const struct perf_event *event, u32 *fd_type,
1193                         const char **filename, u64 *probe_offset,
1194                         bool perf_type_tracepoint)
1195 {
1196         const char *pevent = trace_event_name(event->tp_event);
1197         const char *group = event->tp_event->class->system;
1198         struct trace_uprobe *tu;
1199
1200         if (perf_type_tracepoint)
1201                 tu = find_probe_event(pevent, group);
1202         else
1203                 tu = event->tp_event->data;
1204         if (!tu)
1205                 return -EINVAL;
1206
1207         *fd_type = is_ret_probe(tu) ? BPF_FD_TYPE_URETPROBE
1208                                     : BPF_FD_TYPE_UPROBE;
1209         *filename = tu->filename;
1210         *probe_offset = tu->offset;
1211         return 0;
1212 }
1213 #endif  /* CONFIG_PERF_EVENTS */
1214
1215 static int
1216 trace_uprobe_register(struct trace_event_call *event, enum trace_reg type,
1217                       void *data)
1218 {
1219         struct trace_uprobe *tu = event->data;
1220         struct trace_event_file *file = data;
1221
1222         switch (type) {
1223         case TRACE_REG_REGISTER:
1224                 return probe_event_enable(tu, file, NULL);
1225
1226         case TRACE_REG_UNREGISTER:
1227                 probe_event_disable(tu, file);
1228                 return 0;
1229
1230 #ifdef CONFIG_PERF_EVENTS
1231         case TRACE_REG_PERF_REGISTER:
1232                 return probe_event_enable(tu, NULL, uprobe_perf_filter);
1233
1234         case TRACE_REG_PERF_UNREGISTER:
1235                 probe_event_disable(tu, NULL);
1236                 return 0;
1237
1238         case TRACE_REG_PERF_OPEN:
1239                 return uprobe_perf_open(tu, data);
1240
1241         case TRACE_REG_PERF_CLOSE:
1242                 return uprobe_perf_close(tu, data);
1243
1244 #endif
1245         default:
1246                 return 0;
1247         }
1248         return 0;
1249 }
1250
1251 static int uprobe_dispatcher(struct uprobe_consumer *con, struct pt_regs *regs)
1252 {
1253         struct trace_uprobe *tu;
1254         struct uprobe_dispatch_data udd;
1255         struct uprobe_cpu_buffer *ucb;
1256         int dsize, esize;
1257         int ret = 0;
1258
1259
1260         tu = container_of(con, struct trace_uprobe, consumer);
1261         tu->nhit++;
1262
1263         udd.tu = tu;
1264         udd.bp_addr = instruction_pointer(regs);
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                 ret |= uprobe_trace_func(tu, regs, ucb, dsize);
1279
1280 #ifdef CONFIG_PERF_EVENTS
1281         if (tu->tp.flags & TP_FLAG_PROFILE)
1282                 ret |= uprobe_perf_func(tu, regs, ucb, dsize);
1283 #endif
1284         uprobe_buffer_put(ucb);
1285         return ret;
1286 }
1287
1288 static int uretprobe_dispatcher(struct uprobe_consumer *con,
1289                                 unsigned long func, struct pt_regs *regs)
1290 {
1291         struct trace_uprobe *tu;
1292         struct uprobe_dispatch_data udd;
1293         struct uprobe_cpu_buffer *ucb;
1294         int dsize, esize;
1295
1296         tu = container_of(con, struct trace_uprobe, consumer);
1297
1298         udd.tu = tu;
1299         udd.bp_addr = func;
1300
1301         current->utask->vaddr = (unsigned long) &udd;
1302
1303         if (WARN_ON_ONCE(!uprobe_cpu_buffer))
1304                 return 0;
1305
1306         dsize = __get_data_size(&tu->tp, regs);
1307         esize = SIZEOF_TRACE_ENTRY(is_ret_probe(tu));
1308
1309         ucb = uprobe_buffer_get();
1310         store_trace_args(ucb->buf, &tu->tp, regs, esize, dsize);
1311
1312         if (tu->tp.flags & TP_FLAG_TRACE)
1313                 uretprobe_trace_func(tu, func, regs, ucb, dsize);
1314
1315 #ifdef CONFIG_PERF_EVENTS
1316         if (tu->tp.flags & TP_FLAG_PROFILE)
1317                 uretprobe_perf_func(tu, func, regs, ucb, dsize);
1318 #endif
1319         uprobe_buffer_put(ucb);
1320         return 0;
1321 }
1322
1323 static struct trace_event_functions uprobe_funcs = {
1324         .trace          = print_uprobe_event
1325 };
1326
1327 static inline void init_trace_event_call(struct trace_uprobe *tu,
1328                                          struct trace_event_call *call)
1329 {
1330         INIT_LIST_HEAD(&call->class->fields);
1331         call->event.funcs = &uprobe_funcs;
1332         call->class->define_fields = uprobe_event_define_fields;
1333
1334         call->flags = TRACE_EVENT_FL_UPROBE;
1335         call->class->reg = trace_uprobe_register;
1336         call->data = tu;
1337 }
1338
1339 static int register_uprobe_event(struct trace_uprobe *tu)
1340 {
1341         struct trace_event_call *call = &tu->tp.call;
1342         int ret = 0;
1343
1344         init_trace_event_call(tu, call);
1345
1346         if (traceprobe_set_print_fmt(&tu->tp, is_ret_probe(tu)) < 0)
1347                 return -ENOMEM;
1348
1349         ret = register_trace_event(&call->event);
1350         if (!ret) {
1351                 kfree(call->print_fmt);
1352                 return -ENODEV;
1353         }
1354
1355         ret = trace_add_event_call(call);
1356
1357         if (ret) {
1358                 pr_info("Failed to register uprobe event: %s\n",
1359                         trace_event_name(call));
1360                 kfree(call->print_fmt);
1361                 unregister_trace_event(&call->event);
1362         }
1363
1364         return ret;
1365 }
1366
1367 static int unregister_uprobe_event(struct trace_uprobe *tu)
1368 {
1369         int ret;
1370
1371         /* tu->event is unregistered in trace_remove_event_call() */
1372         ret = trace_remove_event_call(&tu->tp.call);
1373         if (ret)
1374                 return ret;
1375         kfree(tu->tp.call.print_fmt);
1376         tu->tp.call.print_fmt = NULL;
1377         return 0;
1378 }
1379
1380 #ifdef CONFIG_PERF_EVENTS
1381 struct trace_event_call *
1382 create_local_trace_uprobe(char *name, unsigned long offs,
1383                           unsigned long ref_ctr_offset, bool is_return)
1384 {
1385         struct trace_uprobe *tu;
1386         struct path path;
1387         int ret;
1388
1389         ret = kern_path(name, LOOKUP_FOLLOW, &path);
1390         if (ret)
1391                 return ERR_PTR(ret);
1392
1393         if (!d_is_reg(path.dentry)) {
1394                 path_put(&path);
1395                 return ERR_PTR(-EINVAL);
1396         }
1397
1398         /*
1399          * local trace_kprobes are not added to dyn_event, so they are never
1400          * searched in find_trace_kprobe(). Therefore, there is no concern of
1401          * duplicated name "DUMMY_EVENT" here.
1402          */
1403         tu = alloc_trace_uprobe(UPROBE_EVENT_SYSTEM, "DUMMY_EVENT", 0,
1404                                 is_return);
1405
1406         if (IS_ERR(tu)) {
1407                 pr_info("Failed to allocate trace_uprobe.(%d)\n",
1408                         (int)PTR_ERR(tu));
1409                 path_put(&path);
1410                 return ERR_CAST(tu);
1411         }
1412
1413         tu->offset = offs;
1414         tu->path = path;
1415         tu->ref_ctr_offset = ref_ctr_offset;
1416         tu->filename = kstrdup(name, GFP_KERNEL);
1417         init_trace_event_call(tu, &tu->tp.call);
1418
1419         if (traceprobe_set_print_fmt(&tu->tp, is_ret_probe(tu)) < 0) {
1420                 ret = -ENOMEM;
1421                 goto error;
1422         }
1423
1424         return &tu->tp.call;
1425 error:
1426         free_trace_uprobe(tu);
1427         return ERR_PTR(ret);
1428 }
1429
1430 void destroy_local_trace_uprobe(struct trace_event_call *event_call)
1431 {
1432         struct trace_uprobe *tu;
1433
1434         tu = container_of(event_call, struct trace_uprobe, tp.call);
1435
1436         kfree(tu->tp.call.print_fmt);
1437         tu->tp.call.print_fmt = NULL;
1438
1439         free_trace_uprobe(tu);
1440 }
1441 #endif /* CONFIG_PERF_EVENTS */
1442
1443 /* Make a trace interface for controling probe points */
1444 static __init int init_uprobe_trace(void)
1445 {
1446         struct dentry *d_tracer;
1447         int ret;
1448
1449         ret = dyn_event_register(&trace_uprobe_ops);
1450         if (ret)
1451                 return ret;
1452
1453         d_tracer = tracing_init_dentry();
1454         if (IS_ERR(d_tracer))
1455                 return 0;
1456
1457         trace_create_file("uprobe_events", 0644, d_tracer,
1458                                     NULL, &uprobe_events_ops);
1459         /* Profile interface */
1460         trace_create_file("uprobe_profile", 0444, d_tracer,
1461                                     NULL, &uprobe_profile_ops);
1462         return 0;
1463 }
1464
1465 fs_initcall(init_uprobe_trace);