libmarkers/tracepoint.c

   1 /*
   2  * Copyright (C) 2008 Mathieu Desnoyers
   3  *
   4  * This program is free software; you can redistribute it and/or modify
   5  * it under the terms of the GNU General Public License as published by
   6  * the Free Software Foundation; either version 2 of the License, or
   7  * (at your option) any later version.
   8  *
   9  * This program is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  * GNU General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU General Public License
  15  * along with this program; if not, write to the Free Software
  16  * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
  17  */
  18 //ust// #include <linux/module.h>
  19 //ust// #include <linux/mutex.h>
  20 //ust// #include <linux/types.h>
  21 //ust// #include <linux/jhash.h>
  22 //ust// #include <linux/list.h>
  23 //ust// #include <linux/rcupdate.h>
  24 //ust// #include <linux/tracepoint.h>
  25 //ust// #include <linux/err.h>
  26 //ust// #include <linux/slab.h>
  27 //ust// #include <linux/immediate.h>
  28
  29 #include <errno.h>
  30
  31 #include "kernelcompat.h"
  32 #include "tracepoint.h"
  33 #include "usterr.h"
  34 #include "list.h"
  35
  36 //extern struct tracepoint __start___tracepoints[] __attribute__((visibility("hidden")));
  37 //extern struct tracepoint __stop___tracepoints[] __attribute__((visibility("hidden")));
  38
  39 /* Set to 1 to enable tracepoint debug output */
  40 static const int tracepoint_debug;
  41
  42 /* libraries that contain tracepoints (struct tracepoint_lib) */
  43 static LIST_HEAD(libs);
  44
  45 /*
  46  * tracepoints_mutex nests inside module_mutex. Tracepoints mutex protects the
  47  * builtin and module tracepoints and the hash table.
  48  */
  49 static DEFINE_MUTEX(tracepoints_mutex);
  50
  51 /*
  52  * Tracepoint hash table, containing the active tracepoints.
  53  * Protected by tracepoints_mutex.
  54  */
  55 #define TRACEPOINT_HASH_BITS 6
  56 #define TRACEPOINT_TABLE_SIZE (1 << TRACEPOINT_HASH_BITS)
  57 static struct hlist_head tracepoint_table[TRACEPOINT_TABLE_SIZE];
  58
  59 /*
  60  * Note about RCU :
  61  * It is used to to delay the free of multiple probes array until a quiescent
  62  * state is reached.
  63  * Tracepoint entries modifications are protected by the tracepoints_mutex.
  64  */
  65 struct tracepoint_entry {
  66         struct hlist_node hlist;
  67         void **funcs;
  68         int refcount;   /* Number of times armed. 0 if disarmed. */
  69         char name[0];
  70 };
  71
  72 struct tp_probes {
  73         union {
  74 //ust//         struct rcu_head rcu;
  75                 struct list_head list;
  76         } u;
  77         void *probes[0];
  78 };
  79
  80 static inline void *allocate_probes(int count)
  81 {
  82         struct tp_probes *p  = kmalloc(count * sizeof(void *)
  83                         + sizeof(struct tp_probes), GFP_KERNEL);
  84         return p == NULL ? NULL : p->probes;
  85 }
  86
  87 //ust// static void rcu_free_old_probes(struct rcu_head *head)
  88 //ust// {
  89 //ust//         kfree(container_of(head, struct tp_probes, u.rcu));
  90 //ust// }
  91
  92 static inline void release_probes(void *old)
  93 {
  94         if (old) {
  95                 struct tp_probes *tp_probes = container_of(old,
  96                         struct tp_probes, probes[0]);
  97 //ust//         call_rcu_sched(&tp_probes->u.rcu, rcu_free_old_probes);
  98                 synchronize_rcu();
  99                 kfree(tp_probes);
 100         }
 101 }
 102
 103 static void debug_print_probes(struct tracepoint_entry *entry)
 104 {
 105         int i;
 106
 107         if (!tracepoint_debug || !entry->funcs)
 108                 return;
 109
 110         for (i = 0; entry->funcs[i]; i++)
 111                 printk(KERN_DEBUG "Probe %d : %p\n", i, entry->funcs[i]);
 112 }
 113
 114 static void *
 115 tracepoint_entry_add_probe(struct tracepoint_entry *entry, void *probe)
 116 {
 117         int nr_probes = 0;
 118         void **old, **new;
 119
 120         WARN_ON(!probe);
 121
 122         debug_print_probes(entry);
 123         old = entry->funcs;
 124         if (old) {
 125                 /* (N -> N+1), (N != 0, 1) probes */
 126                 for (nr_probes = 0; old[nr_probes]; nr_probes++)
 127                         if (old[nr_probes] == probe)
 128                                 return ERR_PTR(-EEXIST);
 129         }
 130         /* + 2 : one for new probe, one for NULL func */
 131         new = allocate_probes(nr_probes + 2);
 132         if (new == NULL)
 133                 return ERR_PTR(-ENOMEM);
 134         if (old)
 135                 memcpy(new, old, nr_probes * sizeof(void *));
 136         new[nr_probes] = probe;
 137         new[nr_probes + 1] = NULL;
 138         entry->refcount = nr_probes + 1;
 139         entry->funcs = new;
 140         debug_print_probes(entry);
 141         return old;
 142 }
 143
 144 static void *
 145 tracepoint_entry_remove_probe(struct tracepoint_entry *entry, void *probe)
 146 {
 147         int nr_probes = 0, nr_del = 0, i;
 148         void **old, **new;
 149
 150         old = entry->funcs;
 151
 152         if (!old)
 153                 return ERR_PTR(-ENOENT);
 154
 155         debug_print_probes(entry);
 156         /* (N -> M), (N > 1, M >= 0) probes */
 157         for (nr_probes = 0; old[nr_probes]; nr_probes++) {
 158                 if ((!probe || old[nr_probes] == probe))
 159                         nr_del++;
 160         }
 161
 162         if (nr_probes - nr_del == 0) {
 163                 /* N -> 0, (N > 1) */
 164                 entry->funcs = NULL;
 165                 entry->refcount = 0;
 166                 debug_print_probes(entry);
 167                 return old;
 168         } else {
 169                 int j = 0;
 170                 /* N -> M, (N > 1, M > 0) */
 171                 /* + 1 for NULL */
 172                 new = allocate_probes(nr_probes - nr_del + 1);
 173                 if (new == NULL)
 174                         return ERR_PTR(-ENOMEM);
 175                 for (i = 0; old[i]; i++)
 176                         if ((probe && old[i] != probe))
 177                                 new[j++] = old[i];
 178                 new[nr_probes - nr_del] = NULL;
 179                 entry->refcount = nr_probes - nr_del;
 180                 entry->funcs = new;
 181         }
 182         debug_print_probes(entry);
 183         return old;
 184 }
 185
 186 /*
 187  * Get tracepoint if the tracepoint is present in the tracepoint hash table.
 188  * Must be called with tracepoints_mutex held.
 189  * Returns NULL if not present.
 190  */
 191 static struct tracepoint_entry *get_tracepoint(const char *name)
 192 {
 193         struct hlist_head *head;
 194         struct hlist_node *node;
 195         struct tracepoint_entry *e;
 196         u32 hash = jhash(name, strlen(name), 0);
 197
 198         head = &tracepoint_table[hash & (TRACEPOINT_TABLE_SIZE - 1)];
 199         hlist_for_each_entry(e, node, head, hlist) {
 200                 if (!strcmp(name, e->name))
 201                         return e;
 202         }
 203         return NULL;
 204 }
 205
 206 /*
 207  * Add the tracepoint to the tracepoint hash table. Must be called with
 208  * tracepoints_mutex held.
 209  */
 210 static struct tracepoint_entry *add_tracepoint(const char *name)
 211 {
 212         struct hlist_head *head;
 213         struct hlist_node *node;
 214         struct tracepoint_entry *e;
 215         size_t name_len = strlen(name) + 1;
 216         u32 hash = jhash(name, name_len-1, 0);
 217
 218         head = &tracepoint_table[hash & (TRACEPOINT_TABLE_SIZE - 1)];
 219         hlist_for_each_entry(e, node, head, hlist) {
 220                 if (!strcmp(name, e->name)) {
 221                         printk(KERN_NOTICE
 222                                 "tracepoint %s busy\n", name);
 223                         return ERR_PTR(-EEXIST);        /* Already there */
 224                 }
 225         }
 226         /*
 227          * Using kmalloc here to allocate a variable length element. Could
 228          * cause some memory fragmentation if overused.
 229          */
 230         e = kmalloc(sizeof(struct tracepoint_entry) + name_len, GFP_KERNEL);
 231         if (!e)
 232                 return ERR_PTR(-ENOMEM);
 233         memcpy(&e->name[0], name, name_len);
 234         e->funcs = NULL;
 235         e->refcount = 0;
 236         hlist_add_head(&e->hlist, head);
 237         return e;
 238 }
 239
 240 /*
 241  * Remove the tracepoint from the tracepoint hash table. Must be called with
 242  * mutex_lock held.
 243  */
 244 static inline void remove_tracepoint(struct tracepoint_entry *e)
 245 {
 246         hlist_del(&e->hlist);
 247         kfree(e);
 248 }
 249
 250 /*
 251  * Sets the probe callback corresponding to one tracepoint.
 252  */
 253 static void set_tracepoint(struct tracepoint_entry **entry,
 254         struct tracepoint *elem, int active)
 255 {
 256         WARN_ON(strcmp((*entry)->name, elem->name) != 0);
 257
 258         /*
 259          * rcu_assign_pointer has a smp_wmb() which makes sure that the new
 260          * probe callbacks array is consistent before setting a pointer to it.
 261          * This array is referenced by __DO_TRACE from
 262          * include/linux/tracepoints.h. A matching smp_read_barrier_depends()
 263          * is used.
 264          */
 265         rcu_assign_pointer(elem->funcs, (*entry)->funcs);
 266         elem->state__imv = active;
 267 }
 268
 269 /*
 270  * Disable a tracepoint and its probe callback.
 271  * Note: only waiting an RCU period after setting elem->call to the empty
 272  * function insures that the original callback is not used anymore. This insured
 273  * by preempt_disable around the call site.
 274  */
 275 static void disable_tracepoint(struct tracepoint *elem)
 276 {
 277         elem->state__imv = 0;
 278         rcu_assign_pointer(elem->funcs, NULL);
 279 }
 280
 281 /**
 282  * tracepoint_update_probe_range - Update a probe range
 283  * @begin: beginning of the range
 284  * @end: end of the range
 285  *
 286  * Updates the probe callback corresponding to a range of tracepoints.
 287  */
 288 void tracepoint_update_probe_range(struct tracepoint *begin,
 289         struct tracepoint *end)
 290 {
 291         struct tracepoint *iter;
 292         struct tracepoint_entry *mark_entry;
 293
 294         mutex_lock(&tracepoints_mutex);
 295         for (iter = begin; iter < end; iter++) {
 296                 mark_entry = get_tracepoint(iter->name);
 297                 if (mark_entry) {
 298                         set_tracepoint(&mark_entry, iter,
 299                                         !!mark_entry->refcount);
 300                 } else {
 301                         disable_tracepoint(iter);
 302                 }
 303         }
 304         mutex_unlock(&tracepoints_mutex);
 305 }
 306
 307 /*
 308  * Update probes, removing the faulty probes.
 309  */
 310 static void tracepoint_update_probes(void)
 311 {
 312         /* Core kernel tracepoints */
 313 //ust// tracepoint_update_probe_range(__start___tracepoints,
 314 //ust//         __stop___tracepoints);
 315         /* tracepoints in modules. */
 316         lib_update_tracepoints();
 317         /* Update immediate values */
 318         core_imv_update();
 319 //ust// module_imv_update();
 320 }
 321
 322 static void *tracepoint_add_probe(const char *name, void *probe)
 323 {
 324         struct tracepoint_entry *entry;
 325         void *old;
 326
 327         entry = get_tracepoint(name);
 328         if (!entry) {
 329                 entry = add_tracepoint(name);
 330                 if (IS_ERR(entry))
 331                         return entry;
 332         }
 333         old = tracepoint_entry_add_probe(entry, probe);
 334         if (IS_ERR(old) && !entry->refcount)
 335                 remove_tracepoint(entry);
 336         return old;
 337 }
 338
 339 /**
 340  * tracepoint_probe_register -  Connect a probe to a tracepoint
 341  * @name: tracepoint name
 342  * @probe: probe handler
 343  *
 344  * Returns 0 if ok, error value on error.
 345  * The probe address must at least be aligned on the architecture pointer size.
 346  */
 347 int tracepoint_probe_register(const char *name, void *probe)
 348 {
 349         void *old;
 350
 351         mutex_lock(&tracepoints_mutex);
 352         old = tracepoint_add_probe(name, probe);
 353         mutex_unlock(&tracepoints_mutex);
 354         if (IS_ERR(old))
 355                 return PTR_ERR(old);
 356
 357         tracepoint_update_probes();             /* may update entry */
 358         release_probes(old);
 359         return 0;
 360 }
 361 //ust// EXPORT_SYMBOL_GPL(tracepoint_probe_register);
 362
 363 static void *tracepoint_remove_probe(const char *name, void *probe)
 364 {
 365         struct tracepoint_entry *entry;
 366         void *old;
 367
 368         entry = get_tracepoint(name);
 369         if (!entry)
 370                 return ERR_PTR(-ENOENT);
 371         old = tracepoint_entry_remove_probe(entry, probe);
 372         if (IS_ERR(old))
 373                 return old;
 374         if (!entry->refcount)
 375                 remove_tracepoint(entry);
 376         return old;
 377 }
 378
 379 /**
 380  * tracepoint_probe_unregister -  Disconnect a probe from a tracepoint
 381  * @name: tracepoint name
 382  * @probe: probe function pointer
 383  *
 384  * We do not need to call a synchronize_sched to make sure the probes have
 385  * finished running before doing a module unload, because the module unload
 386  * itself uses stop_machine(), which insures that every preempt disabled section
 387  * have finished.
 388  */
 389 int tracepoint_probe_unregister(const char *name, void *probe)
 390 {
 391         void *old;
 392
 393         mutex_lock(&tracepoints_mutex);
 394         old = tracepoint_remove_probe(name, probe);
 395         mutex_unlock(&tracepoints_mutex);
 396         if (IS_ERR(old))
 397                 return PTR_ERR(old);
 398
 399         tracepoint_update_probes();             /* may update entry */
 400         release_probes(old);
 401         return 0;
 402 }
 403 //ust// EXPORT_SYMBOL_GPL(tracepoint_probe_unregister);
 404
 405 static LIST_HEAD(old_probes);
 406 static int need_update;
 407
 408 static void tracepoint_add_old_probes(void *old)
 409 {
 410         need_update = 1;
 411         if (old) {
 412                 struct tp_probes *tp_probes = container_of(old,
 413                         struct tp_probes, probes[0]);
 414                 list_add(&tp_probes->u.list, &old_probes);
 415         }
 416 }
 417
 418 /**
 419  * tracepoint_probe_register_noupdate -  register a probe but not connect
 420  * @name: tracepoint name
 421  * @probe: probe handler
 422  *
 423  * caller must call tracepoint_probe_update_all()
 424  */
 425 int tracepoint_probe_register_noupdate(const char *name, void *probe)
 426 {
 427         void *old;
 428
 429         mutex_lock(&tracepoints_mutex);
 430         old = tracepoint_add_probe(name, probe);
 431         if (IS_ERR(old)) {
 432                 mutex_unlock(&tracepoints_mutex);
 433                 return PTR_ERR(old);
 434         }
 435         tracepoint_add_old_probes(old);
 436         mutex_unlock(&tracepoints_mutex);
 437         return 0;
 438 }
 439 //ust// EXPORT_SYMBOL_GPL(tracepoint_probe_register_noupdate);
 440
 441 /**
 442  * tracepoint_probe_unregister_noupdate -  remove a probe but not disconnect
 443  * @name: tracepoint name
 444  * @probe: probe function pointer
 445  *
 446  * caller must call tracepoint_probe_update_all()
 447  */
 448 int tracepoint_probe_unregister_noupdate(const char *name, void *probe)
 449 {
 450         void *old;
 451
 452         mutex_lock(&tracepoints_mutex);
 453         old = tracepoint_remove_probe(name, probe);
 454         if (IS_ERR(old)) {
 455                 mutex_unlock(&tracepoints_mutex);
 456                 return PTR_ERR(old);
 457         }
 458         tracepoint_add_old_probes(old);
 459         mutex_unlock(&tracepoints_mutex);
 460         return 0;
 461 }
 462 //ust// EXPORT_SYMBOL_GPL(tracepoint_probe_unregister_noupdate);
 463
 464 /**
 465  * tracepoint_probe_update_all -  update tracepoints
 466  */
 467 void tracepoint_probe_update_all(void)
 468 {
 469         LIST_HEAD(release_probes);
 470         struct tp_probes *pos, *next;
 471
 472         mutex_lock(&tracepoints_mutex);
 473         if (!need_update) {
 474                 mutex_unlock(&tracepoints_mutex);
 475                 return;
 476         }
 477         if (!list_empty(&old_probes))
 478                 list_replace_init(&old_probes, &release_probes);
 479         need_update = 0;
 480         mutex_unlock(&tracepoints_mutex);
 481
 482         tracepoint_update_probes();
 483         list_for_each_entry_safe(pos, next, &release_probes, u.list) {
 484                 list_del(&pos->u.list);
 485 //ust//         call_rcu_sched(&pos->u.rcu, rcu_free_old_probes);
 486                 synchronize_rcu();
 487                 kfree(pos);
 488         }
 489 }
 490 //ust// EXPORT_SYMBOL_GPL(tracepoint_probe_update_all);
 491
 492 /**
 493  * tracepoint_get_iter_range - Get a next tracepoint iterator given a range.
 494  * @tracepoint: current tracepoints (in), next tracepoint (out)
 495  * @begin: beginning of the range
 496  * @end: end of the range
 497  *
 498  * Returns whether a next tracepoint has been found (1) or not (0).
 499  * Will return the first tracepoint in the range if the input tracepoint is
 500  * NULL.
 501  */
 502 int tracepoint_get_iter_range(struct tracepoint **tracepoint,
 503         struct tracepoint *begin, struct tracepoint *end)
 504 {
 505         if (!*tracepoint && begin != end) {
 506                 *tracepoint = begin;
 507                 return 1;
 508         }
 509         if (*tracepoint >= begin && *tracepoint < end)
 510                 return 1;
 511         return 0;
 512 }
 513 //ust// EXPORT_SYMBOL_GPL(tracepoint_get_iter_range);
 514
 515 static void tracepoint_get_iter(struct tracepoint_iter *iter)
 516 {
 517         int found = 0;
 518
 519 //ust// /* Core kernel tracepoints */
 520 //ust// if (!iter->module) {
 521 //ust//         found = tracepoint_get_iter_range(&iter->tracepoint,
 522 //ust//                         __start___tracepoints, __stop___tracepoints);
 523 //ust//         if (found)
 524 //ust//                 goto end;
 525 //ust// }
 526         /* tracepoints in libs. */
 527         found = lib_get_iter_tracepoints(iter);
 528 end:
 529         if (!found)
 530                 tracepoint_iter_reset(iter);
 531 }
 532
 533 void tracepoint_iter_start(struct tracepoint_iter *iter)
 534 {
 535         tracepoint_get_iter(iter);
 536 }
 537 //ust// EXPORT_SYMBOL_GPL(tracepoint_iter_start);
 538
 539 void tracepoint_iter_next(struct tracepoint_iter *iter)
 540 {
 541         iter->tracepoint++;
 542         /*
 543          * iter->tracepoint may be invalid because we blindly incremented it.
 544          * Make sure it is valid by marshalling on the tracepoints, getting the
 545          * tracepoints from following modules if necessary.
 546          */
 547         tracepoint_get_iter(iter);
 548 }
 549 //ust// EXPORT_SYMBOL_GPL(tracepoint_iter_next);
 550
 551 void tracepoint_iter_stop(struct tracepoint_iter *iter)
 552 {
 553 }
 554 //ust// EXPORT_SYMBOL_GPL(tracepoint_iter_stop);
 555
 556 void tracepoint_iter_reset(struct tracepoint_iter *iter)
 557 {
 558 //ust// iter->module = NULL;
 559         iter->tracepoint = NULL;
 560 }
 561 //ust// EXPORT_SYMBOL_GPL(tracepoint_iter_reset);
 562
 563 //ust// #ifdef CONFIG_MODULES
 564
 565 //ust// int tracepoint_module_notify(struct notifier_block *self,
 566 //ust//                              unsigned long val, void *data)
 567 //ust// {
 568 //ust//         struct module *mod = data;
 569 //ust//
 570 //ust//         switch (val) {
 571 //ust//         case MODULE_STATE_COMING:
 572 //ust//                 tracepoint_update_probe_range(mod->tracepoints,
 573 //ust//                         mod->tracepoints + mod->num_tracepoints);
 574 //ust//                 break;
 575 //ust//         case MODULE_STATE_GOING:
 576 //ust//                 tracepoint_update_probe_range(mod->tracepoints,
 577 //ust//                         mod->tracepoints + mod->num_tracepoints);
 578 //ust//                 break;
 579 //ust//         }
 580 //ust//         return 0;
 581 //ust// }
 582
 583 //ust// struct notifier_block tracepoint_module_nb = {
 584 //ust//         .notifier_call = tracepoint_module_notify,
 585 //ust//         .priority = 0,
 586 //ust// };
 587
 588 //ust// static int init_tracepoints(void)
 589 //ust// {
 590 //ust//         return register_module_notifier(&tracepoint_module_nb);
 591 //ust// }
 592 //ust// __initcall(init_tracepoints);
 593
 594 //ust// #endif /* CONFIG_MODULES */
 595
 596 /*
 597  * Returns 0 if current not found.
 598  * Returns 1 if current found.
 599  */
 600 int lib_get_iter_tracepoints(struct tracepoint_iter *iter)
 601 {
 602         struct tracepoint_lib *iter_lib;
 603         int found = 0;
 604
 605 //ust// mutex_lock(&module_mutex);
 606         list_for_each_entry(iter_lib, &libs, list) {
 607                 if (iter_lib < iter->lib)
 608                         continue;
 609                 else if (iter_lib > iter->lib)
 610                         iter->tracepoint = NULL;
 611                 found = marker_get_iter_range(&iter->tracepoint,
 612                         iter_lib->tracepoints_start,
 613                         iter_lib->tracepoints_start + iter_lib->tracepoints_count);
 614                 if (found) {
 615                         iter->lib = iter_lib;
 616                         break;
 617                 }
 618         }
 619 //ust// mutex_unlock(&module_mutex);
 620         return found;
 621 }
 622
 623 void lib_update_tracepoints(void)
 624 {
 625         struct tracepoint_lib *lib;
 626
 627 //ust// mutex_lock(&module_mutex);
 628         list_for_each_entry(lib, &libs, list)
 629                 tracepoint_update_probe_range(lib->tracepoints_start,
 630                                 lib->tracepoints_start + lib->tracepoints_count);
 631 //ust// mutex_unlock(&module_mutex);
 632 }
 633
 634 static void (*new_tracepoint_cb)(struct tracepoint *) = NULL;
 635
 636 void tracepoint_set_new_tracepoint_cb(void (*cb)(struct tracepoint *))
 637 {
 638         new_tracepoint_cb = cb;
 639 }
 640
 641 static void new_tracepoints(struct tracepoint *start, struct tracepoint *end)
 642 {
 643         if(new_tracepoint_cb) {
 644                 struct tracepoint *t;
 645                 for(t=start; t < end; t++) {
 646                         new_tracepoint_cb(t);
 647                 }
 648         }
 649 }
 650
 651 int tracepoint_register_lib(struct tracepoint *tracepoints_start, int tracepoints_count)
 652 {
 653         struct tracepoint_lib *pl;
 654
 655         pl = (struct tracepoint_lib *) malloc(sizeof(struct tracepoint_lib));
 656
 657         pl->tracepoints_start = tracepoints_start;
 658         pl->tracepoints_count = tracepoints_count;
 659
 660         /* FIXME: maybe protect this with its own mutex? */
 661         mutex_lock(&tracepoints_mutex);
 662         list_add(&pl->list, &libs);
 663         mutex_unlock(&tracepoints_mutex);
 664
 665         new_tracepoints(tracepoints_start, tracepoints_start + tracepoints_count);
 666
 667         /* FIXME: update just the loaded lib */
 668         lib_update_tracepoints();
 669
 670         DBG("just registered a tracepoints section from %p and having %d tracepoints", tracepoints_start, tracepoints_count);
 671
 672         return 0;
 673 }
 674
 675 int tracepoint_unregister_lib(struct tracepoint *tracepoints_start, int tracepoints_count)
 676 {
 677         /*FIXME: implement; but before implementing, tracepoint_register_lib must
 678           have appropriate locking. */
 679
 680         return 0;
 681 }