libust/tracepoint.c

   1 /*
   2  * Copyright (C) 2008 Mathieu Desnoyers
   3  * Copyright (C) 2009 Pierre-Marc Fournier
   4  *
   5  * This program is free software; you can redistribute it and/or
   6  * modify it under the terms of the GNU General Public License
   7  * as published by the Free Software Foundation; either version 2
   8  * of the License, or (at your option) any later version.
   9  *
  10  * This program is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13  * GNU General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU General Public License
  16  * along with this program; if not, write to the Free Software
  17  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
  18  *
  19  * Ported to userspace by Pierre-Marc Fournier.
  20  */
  21
  22 //ust// #include <linux/module.h>
  23 //ust// #include <linux/mutex.h>
  24 //ust// #include <linux/types.h>
  25 //ust// #include <linux/jhash.h>
  26 //ust// #include <linux/list.h>
  27 //ust// #include <linux/rcupdate.h>
  28 //ust// #include <linux/tracepoint.h>
  29 //ust// #include <linux/err.h>
  30 //ust// #include <linux/slab.h>
  31 //ust// #include <linux/immediate.h>
  32
  33 #include <errno.h>
  34
  35 #include "kernelcompat.h"
  36 #include "tracepoint.h"
  37 #include "usterr.h"
  38 #include "list.h"
  39
  40 //extern struct tracepoint __start___tracepoints[] __attribute__((visibility("hidden")));
  41 //extern struct tracepoint __stop___tracepoints[] __attribute__((visibility("hidden")));
  42
  43 /* Set to 1 to enable tracepoint debug output */
  44 static const int tracepoint_debug;
  45
  46 /* libraries that contain tracepoints (struct tracepoint_lib) */
  47 static LIST_HEAD(libs);
  48
  49 /*
  50  * tracepoints_mutex nests inside module_mutex. Tracepoints mutex protects the
  51  * builtin and module tracepoints and the hash table.
  52  */
  53 static DEFINE_MUTEX(tracepoints_mutex);
  54
  55 /*
  56  * Tracepoint hash table, containing the active tracepoints.
  57  * Protected by tracepoints_mutex.
  58  */
  59 #define TRACEPOINT_HASH_BITS 6
  60 #define TRACEPOINT_TABLE_SIZE (1 << TRACEPOINT_HASH_BITS)
  61 static struct hlist_head tracepoint_table[TRACEPOINT_TABLE_SIZE];
  62
  63 /*
  64  * Note about RCU :
  65  * It is used to to delay the free of multiple probes array until a quiescent
  66  * state is reached.
  67  * Tracepoint entries modifications are protected by the tracepoints_mutex.
  68  */
  69 struct tracepoint_entry {
  70         struct hlist_node hlist;
  71         void **funcs;
  72         int refcount;   /* Number of times armed. 0 if disarmed. */
  73         char name[0];
  74 };
  75
  76 struct tp_probes {
  77         union {
  78 //ust//         struct rcu_head rcu;
  79                 struct list_head list;
  80         } u;
  81         void *probes[0];
  82 };
  83
  84 static inline void *allocate_probes(int count)
  85 {
  86         struct tp_probes *p  = kmalloc(count * sizeof(void *)
  87                         + sizeof(struct tp_probes), GFP_KERNEL);
  88         return p == NULL ? NULL : p->probes;
  89 }
  90
  91 //ust// static void rcu_free_old_probes(struct rcu_head *head)
  92 //ust// {
  93 //ust//         kfree(container_of(head, struct tp_probes, u.rcu));
  94 //ust// }
  95
  96 static inline void release_probes(void *old)
  97 {
  98         if (old) {
  99                 struct tp_probes *tp_probes = container_of(old,
 100                         struct tp_probes, probes[0]);
 101 //ust//         call_rcu_sched(&tp_probes->u.rcu, rcu_free_old_probes);
 102                 synchronize_rcu();
 103                 kfree(tp_probes);
 104         }
 105 }
 106
 107 static void debug_print_probes(struct tracepoint_entry *entry)
 108 {
 109         int i;
 110
 111         if (!tracepoint_debug || !entry->funcs)
 112                 return;
 113
 114         for (i = 0; entry->funcs[i]; i++)
 115                 printk(KERN_DEBUG "Probe %d : %p\n", i, entry->funcs[i]);
 116 }
 117
 118 static void *
 119 tracepoint_entry_add_probe(struct tracepoint_entry *entry, void *probe)
 120 {
 121         int nr_probes = 0;
 122         void **old, **new;
 123
 124         WARN_ON(!probe);
 125
 126         debug_print_probes(entry);
 127         old = entry->funcs;
 128         if (old) {
 129                 /* (N -> N+1), (N != 0, 1) probes */
 130                 for (nr_probes = 0; old[nr_probes]; nr_probes++)
 131                         if (old[nr_probes] == probe)
 132                                 return ERR_PTR(-EEXIST);
 133         }
 134         /* + 2 : one for new probe, one for NULL func */
 135         new = allocate_probes(nr_probes + 2);
 136         if (new == NULL)
 137                 return ERR_PTR(-ENOMEM);
 138         if (old)
 139                 memcpy(new, old, nr_probes * sizeof(void *));
 140         new[nr_probes] = probe;
 141         new[nr_probes + 1] = NULL;
 142         entry->refcount = nr_probes + 1;
 143         entry->funcs = new;
 144         debug_print_probes(entry);
 145         return old;
 146 }
 147
 148 static void *
 149 tracepoint_entry_remove_probe(struct tracepoint_entry *entry, void *probe)
 150 {
 151         int nr_probes = 0, nr_del = 0, i;
 152         void **old, **new;
 153
 154         old = entry->funcs;
 155
 156         if (!old)
 157                 return ERR_PTR(-ENOENT);
 158
 159         debug_print_probes(entry);
 160         /* (N -> M), (N > 1, M >= 0) probes */
 161         for (nr_probes = 0; old[nr_probes]; nr_probes++) {
 162                 if ((!probe || old[nr_probes] == probe))
 163                         nr_del++;
 164         }
 165
 166         if (nr_probes - nr_del == 0) {
 167                 /* N -> 0, (N > 1) */
 168                 entry->funcs = NULL;
 169                 entry->refcount = 0;
 170                 debug_print_probes(entry);
 171                 return old;
 172         } else {
 173                 int j = 0;
 174                 /* N -> M, (N > 1, M > 0) */
 175                 /* + 1 for NULL */
 176                 new = allocate_probes(nr_probes - nr_del + 1);
 177                 if (new == NULL)
 178                         return ERR_PTR(-ENOMEM);
 179                 for (i = 0; old[i]; i++)
 180                         if ((probe && old[i] != probe))
 181                                 new[j++] = old[i];
 182                 new[nr_probes - nr_del] = NULL;
 183                 entry->refcount = nr_probes - nr_del;
 184                 entry->funcs = new;
 185         }
 186         debug_print_probes(entry);
 187         return old;
 188 }
 189
 190 /*
 191  * Get tracepoint if the tracepoint is present in the tracepoint hash table.
 192  * Must be called with tracepoints_mutex held.
 193  * Returns NULL if not present.
 194  */
 195 static struct tracepoint_entry *get_tracepoint(const char *name)
 196 {
 197         struct hlist_head *head;
 198         struct hlist_node *node;
 199         struct tracepoint_entry *e;
 200         u32 hash = jhash(name, strlen(name), 0);
 201
 202         head = &tracepoint_table[hash & (TRACEPOINT_TABLE_SIZE - 1)];
 203         hlist_for_each_entry(e, node, head, hlist) {
 204                 if (!strcmp(name, e->name))
 205                         return e;
 206         }
 207         return NULL;
 208 }
 209
 210 /*
 211  * Add the tracepoint to the tracepoint hash table. Must be called with
 212  * tracepoints_mutex held.
 213  */
 214 static struct tracepoint_entry *add_tracepoint(const char *name)
 215 {
 216         struct hlist_head *head;
 217         struct hlist_node *node;
 218         struct tracepoint_entry *e;
 219         size_t name_len = strlen(name) + 1;
 220         u32 hash = jhash(name, name_len-1, 0);
 221
 222         head = &tracepoint_table[hash & (TRACEPOINT_TABLE_SIZE - 1)];
 223         hlist_for_each_entry(e, node, head, hlist) {
 224                 if (!strcmp(name, e->name)) {
 225                         printk(KERN_NOTICE
 226                                 "tracepoint %s busy\n", name);
 227                         return ERR_PTR(-EEXIST);        /* Already there */
 228                 }
 229         }
 230         /*
 231          * Using kmalloc here to allocate a variable length element. Could
 232          * cause some memory fragmentation if overused.
 233          */
 234         e = kmalloc(sizeof(struct tracepoint_entry) + name_len, GFP_KERNEL);
 235         if (!e)
 236                 return ERR_PTR(-ENOMEM);
 237         memcpy(&e->name[0], name, name_len);
 238         e->funcs = NULL;
 239         e->refcount = 0;
 240         hlist_add_head(&e->hlist, head);
 241         return e;
 242 }
 243
 244 /*
 245  * Remove the tracepoint from the tracepoint hash table. Must be called with
 246  * mutex_lock held.
 247  */
 248 static inline void remove_tracepoint(struct tracepoint_entry *e)
 249 {
 250         hlist_del(&e->hlist);
 251         kfree(e);
 252 }
 253
 254 /*
 255  * Sets the probe callback corresponding to one tracepoint.
 256  */
 257 static void set_tracepoint(struct tracepoint_entry **entry,
 258         struct tracepoint *elem, int active)
 259 {
 260         WARN_ON(strcmp((*entry)->name, elem->name) != 0);
 261
 262         /*
 263          * rcu_assign_pointer has a smp_wmb() which makes sure that the new
 264          * probe callbacks array is consistent before setting a pointer to it.
 265          * This array is referenced by __DO_TRACE from
 266          * include/linux/tracepoints.h. A matching smp_read_barrier_depends()
 267          * is used.
 268          */
 269         rcu_assign_pointer(elem->funcs, (*entry)->funcs);
 270         elem->state__imv = active;
 271 }
 272
 273 /*
 274  * Disable a tracepoint and its probe callback.
 275  * Note: only waiting an RCU period after setting elem->call to the empty
 276  * function insures that the original callback is not used anymore. This insured
 277  * by preempt_disable around the call site.
 278  */
 279 static void disable_tracepoint(struct tracepoint *elem)
 280 {
 281         elem->state__imv = 0;
 282         rcu_assign_pointer(elem->funcs, NULL);
 283 }
 284
 285 /**
 286  * tracepoint_update_probe_range - Update a probe range
 287  * @begin: beginning of the range
 288  * @end: end of the range
 289  *
 290  * Updates the probe callback corresponding to a range of tracepoints.
 291  */
 292 void tracepoint_update_probe_range(struct tracepoint *begin,
 293         struct tracepoint *end)
 294 {
 295         struct tracepoint *iter;
 296         struct tracepoint_entry *mark_entry;
 297
 298         mutex_lock(&tracepoints_mutex);
 299         for (iter = begin; iter < end; iter++) {
 300                 mark_entry = get_tracepoint(iter->name);
 301                 if (mark_entry) {
 302                         set_tracepoint(&mark_entry, iter,
 303                                         !!mark_entry->refcount);
 304                 } else {
 305                         disable_tracepoint(iter);
 306                 }
 307         }
 308         mutex_unlock(&tracepoints_mutex);
 309 }
 310
 311 /*
 312  * Update probes, removing the faulty probes.
 313  */
 314 static void tracepoint_update_probes(void)
 315 {
 316         /* Core kernel tracepoints */
 317 //ust// tracepoint_update_probe_range(__start___tracepoints,
 318 //ust//         __stop___tracepoints);
 319         /* tracepoints in modules. */
 320         lib_update_tracepoints();
 321         /* Update immediate values */
 322         core_imv_update();
 323 //ust// module_imv_update();
 324 }
 325
 326 static void *tracepoint_add_probe(const char *name, void *probe)
 327 {
 328         struct tracepoint_entry *entry;
 329         void *old;
 330
 331         entry = get_tracepoint(name);
 332         if (!entry) {
 333                 entry = add_tracepoint(name);
 334                 if (IS_ERR(entry))
 335                         return entry;
 336         }
 337         old = tracepoint_entry_add_probe(entry, probe);
 338         if (IS_ERR(old) && !entry->refcount)
 339                 remove_tracepoint(entry);
 340         return old;
 341 }
 342
 343 /**
 344  * tracepoint_probe_register -  Connect a probe to a tracepoint
 345  * @name: tracepoint name
 346  * @probe: probe handler
 347  *
 348  * Returns 0 if ok, error value on error.
 349  * The probe address must at least be aligned on the architecture pointer size.
 350  */
 351 int tracepoint_probe_register(const char *name, void *probe)
 352 {
 353         void *old;
 354
 355         mutex_lock(&tracepoints_mutex);
 356         old = tracepoint_add_probe(name, probe);
 357         mutex_unlock(&tracepoints_mutex);
 358         if (IS_ERR(old))
 359                 return PTR_ERR(old);
 360
 361         tracepoint_update_probes();             /* may update entry */
 362         release_probes(old);
 363         return 0;
 364 }
 365 //ust// EXPORT_SYMBOL_GPL(tracepoint_probe_register);
 366
 367 static void *tracepoint_remove_probe(const char *name, void *probe)
 368 {
 369         struct tracepoint_entry *entry;
 370         void *old;
 371
 372         entry = get_tracepoint(name);
 373         if (!entry)
 374                 return ERR_PTR(-ENOENT);
 375         old = tracepoint_entry_remove_probe(entry, probe);
 376         if (IS_ERR(old))
 377                 return old;
 378         if (!entry->refcount)
 379                 remove_tracepoint(entry);
 380         return old;
 381 }
 382
 383 /**
 384  * tracepoint_probe_unregister -  Disconnect a probe from a tracepoint
 385  * @name: tracepoint name
 386  * @probe: probe function pointer
 387  *
 388  * We do not need to call a synchronize_sched to make sure the probes have
 389  * finished running before doing a module unload, because the module unload
 390  * itself uses stop_machine(), which insures that every preempt disabled section
 391  * have finished.
 392  */
 393 int tracepoint_probe_unregister(const char *name, void *probe)
 394 {
 395         void *old;
 396
 397         mutex_lock(&tracepoints_mutex);
 398         old = tracepoint_remove_probe(name, probe);
 399         mutex_unlock(&tracepoints_mutex);
 400         if (IS_ERR(old))
 401                 return PTR_ERR(old);
 402
 403         tracepoint_update_probes();             /* may update entry */
 404         release_probes(old);
 405         return 0;
 406 }
 407 //ust// EXPORT_SYMBOL_GPL(tracepoint_probe_unregister);
 408
 409 static LIST_HEAD(old_probes);
 410 static int need_update;
 411
 412 static void tracepoint_add_old_probes(void *old)
 413 {
 414         need_update = 1;
 415         if (old) {
 416                 struct tp_probes *tp_probes = container_of(old,
 417                         struct tp_probes, probes[0]);
 418                 list_add(&tp_probes->u.list, &old_probes);
 419         }
 420 }
 421
 422 /**
 423  * tracepoint_probe_register_noupdate -  register a probe but not connect
 424  * @name: tracepoint name
 425  * @probe: probe handler
 426  *
 427  * caller must call tracepoint_probe_update_all()
 428  */
 429 int tracepoint_probe_register_noupdate(const char *name, void *probe)
 430 {
 431         void *old;
 432
 433         mutex_lock(&tracepoints_mutex);
 434         old = tracepoint_add_probe(name, probe);
 435         if (IS_ERR(old)) {
 436                 mutex_unlock(&tracepoints_mutex);
 437                 return PTR_ERR(old);
 438         }
 439         tracepoint_add_old_probes(old);
 440         mutex_unlock(&tracepoints_mutex);
 441         return 0;
 442 }
 443 //ust// EXPORT_SYMBOL_GPL(tracepoint_probe_register_noupdate);
 444
 445 /**
 446  * tracepoint_probe_unregister_noupdate -  remove a probe but not disconnect
 447  * @name: tracepoint name
 448  * @probe: probe function pointer
 449  *
 450  * caller must call tracepoint_probe_update_all()
 451  */
 452 int tracepoint_probe_unregister_noupdate(const char *name, void *probe)
 453 {
 454         void *old;
 455
 456         mutex_lock(&tracepoints_mutex);
 457         old = tracepoint_remove_probe(name, probe);
 458         if (IS_ERR(old)) {
 459                 mutex_unlock(&tracepoints_mutex);
 460                 return PTR_ERR(old);
 461         }
 462         tracepoint_add_old_probes(old);
 463         mutex_unlock(&tracepoints_mutex);
 464         return 0;
 465 }
 466 //ust// EXPORT_SYMBOL_GPL(tracepoint_probe_unregister_noupdate);
 467
 468 /**
 469  * tracepoint_probe_update_all -  update tracepoints
 470  */
 471 void tracepoint_probe_update_all(void)
 472 {
 473         LIST_HEAD(release_probes);
 474         struct tp_probes *pos, *next;
 475
 476         mutex_lock(&tracepoints_mutex);
 477         if (!need_update) {
 478                 mutex_unlock(&tracepoints_mutex);
 479                 return;
 480         }
 481         if (!list_empty(&old_probes))
 482                 list_replace_init(&old_probes, &release_probes);
 483         need_update = 0;
 484         mutex_unlock(&tracepoints_mutex);
 485
 486         tracepoint_update_probes();
 487         list_for_each_entry_safe(pos, next, &release_probes, u.list) {
 488                 list_del(&pos->u.list);
 489 //ust//         call_rcu_sched(&pos->u.rcu, rcu_free_old_probes);
 490                 synchronize_rcu();
 491                 kfree(pos);
 492         }
 493 }
 494 //ust// EXPORT_SYMBOL_GPL(tracepoint_probe_update_all);
 495
 496 /**
 497  * tracepoint_get_iter_range - Get a next tracepoint iterator given a range.
 498  * @tracepoint: current tracepoints (in), next tracepoint (out)
 499  * @begin: beginning of the range
 500  * @end: end of the range
 501  *
 502  * Returns whether a next tracepoint has been found (1) or not (0).
 503  * Will return the first tracepoint in the range if the input tracepoint is
 504  * NULL.
 505  */
 506 int tracepoint_get_iter_range(struct tracepoint **tracepoint,
 507         struct tracepoint *begin, struct tracepoint *end)
 508 {
 509         if (!*tracepoint && begin != end) {
 510                 *tracepoint = begin;
 511                 return 1;
 512         }
 513         if (*tracepoint >= begin && *tracepoint < end)
 514                 return 1;
 515         return 0;
 516 }
 517 //ust// EXPORT_SYMBOL_GPL(tracepoint_get_iter_range);
 518
 519 static void tracepoint_get_iter(struct tracepoint_iter *iter)
 520 {
 521         int found = 0;
 522
 523 //ust// /* Core kernel tracepoints */
 524 //ust// if (!iter->module) {
 525 //ust//         found = tracepoint_get_iter_range(&iter->tracepoint,
 526 //ust//                         __start___tracepoints, __stop___tracepoints);
 527 //ust//         if (found)
 528 //ust//                 goto end;
 529 //ust// }
 530         /* tracepoints in libs. */
 531         found = lib_get_iter_tracepoints(iter);
 532 end:
 533         if (!found)
 534                 tracepoint_iter_reset(iter);
 535 }
 536
 537 void tracepoint_iter_start(struct tracepoint_iter *iter)
 538 {
 539         tracepoint_get_iter(iter);
 540 }
 541 //ust// EXPORT_SYMBOL_GPL(tracepoint_iter_start);
 542
 543 void tracepoint_iter_next(struct tracepoint_iter *iter)
 544 {
 545         iter->tracepoint++;
 546         /*
 547          * iter->tracepoint may be invalid because we blindly incremented it.
 548          * Make sure it is valid by marshalling on the tracepoints, getting the
 549          * tracepoints from following modules if necessary.
 550          */
 551         tracepoint_get_iter(iter);
 552 }
 553 //ust// EXPORT_SYMBOL_GPL(tracepoint_iter_next);
 554
 555 void tracepoint_iter_stop(struct tracepoint_iter *iter)
 556 {
 557 }
 558 //ust// EXPORT_SYMBOL_GPL(tracepoint_iter_stop);
 559
 560 void tracepoint_iter_reset(struct tracepoint_iter *iter)
 561 {
 562 //ust// iter->module = NULL;
 563         iter->tracepoint = NULL;
 564 }
 565 //ust// EXPORT_SYMBOL_GPL(tracepoint_iter_reset);
 566
 567 //ust// #ifdef CONFIG_MODULES
 568
 569 //ust// int tracepoint_module_notify(struct notifier_block *self,
 570 //ust//                              unsigned long val, void *data)
 571 //ust// {
 572 //ust//         struct module *mod = data;
 573 //ust//
 574 //ust//         switch (val) {
 575 //ust//         case MODULE_STATE_COMING:
 576 //ust//                 tracepoint_update_probe_range(mod->tracepoints,
 577 //ust//                         mod->tracepoints + mod->num_tracepoints);
 578 //ust//                 break;
 579 //ust//         case MODULE_STATE_GOING:
 580 //ust//                 tracepoint_update_probe_range(mod->tracepoints,
 581 //ust//                         mod->tracepoints + mod->num_tracepoints);
 582 //ust//                 break;
 583 //ust//         }
 584 //ust//         return 0;
 585 //ust// }
 586
 587 //ust// struct notifier_block tracepoint_module_nb = {
 588 //ust//         .notifier_call = tracepoint_module_notify,
 589 //ust//         .priority = 0,
 590 //ust// };
 591
 592 //ust// static int init_tracepoints(void)
 593 //ust// {
 594 //ust//         return register_module_notifier(&tracepoint_module_nb);
 595 //ust// }
 596 //ust// __initcall(init_tracepoints);
 597
 598 //ust// #endif /* CONFIG_MODULES */
 599
 600 /*
 601  * Returns 0 if current not found.
 602  * Returns 1 if current found.
 603  */
 604 int lib_get_iter_tracepoints(struct tracepoint_iter *iter)
 605 {
 606         struct tracepoint_lib *iter_lib;
 607         int found = 0;
 608
 609 //ust// mutex_lock(&module_mutex);
 610         list_for_each_entry(iter_lib, &libs, list) {
 611                 if (iter_lib < iter->lib)
 612                         continue;
 613                 else if (iter_lib > iter->lib)
 614                         iter->tracepoint = NULL;
 615                 found = marker_get_iter_range(&iter->tracepoint,
 616                         iter_lib->tracepoints_start,
 617                         iter_lib->tracepoints_start + iter_lib->tracepoints_count);
 618                 if (found) {
 619                         iter->lib = iter_lib;
 620                         break;
 621                 }
 622         }
 623 //ust// mutex_unlock(&module_mutex);
 624         return found;
 625 }
 626
 627 void lib_update_tracepoints(void)
 628 {
 629         struct tracepoint_lib *lib;
 630
 631 //ust// mutex_lock(&module_mutex);
 632         list_for_each_entry(lib, &libs, list)
 633                 tracepoint_update_probe_range(lib->tracepoints_start,
 634                                 lib->tracepoints_start + lib->tracepoints_count);
 635 //ust// mutex_unlock(&module_mutex);
 636 }
 637
 638 static void (*new_tracepoint_cb)(struct tracepoint *) = NULL;
 639
 640 void tracepoint_set_new_tracepoint_cb(void (*cb)(struct tracepoint *))
 641 {
 642         new_tracepoint_cb = cb;
 643 }
 644
 645 static void new_tracepoints(struct tracepoint *start, struct tracepoint *end)
 646 {
 647         if(new_tracepoint_cb) {
 648                 struct tracepoint *t;
 649                 for(t=start; t < end; t++) {
 650                         new_tracepoint_cb(t);
 651                 }
 652         }
 653 }
 654
 655 int tracepoint_register_lib(struct tracepoint *tracepoints_start, int tracepoints_count)
 656 {
 657         struct tracepoint_lib *pl;
 658
 659         pl = (struct tracepoint_lib *) malloc(sizeof(struct tracepoint_lib));
 660
 661         pl->tracepoints_start = tracepoints_start;
 662         pl->tracepoints_count = tracepoints_count;
 663
 664         /* FIXME: maybe protect this with its own mutex? */
 665         mutex_lock(&tracepoints_mutex);
 666         list_add(&pl->list, &libs);
 667         mutex_unlock(&tracepoints_mutex);
 668
 669         new_tracepoints(tracepoints_start, tracepoints_start + tracepoints_count);
 670
 671         /* FIXME: update just the loaded lib */
 672         lib_update_tracepoints();
 673
 674         DBG("just registered a tracepoints section from %p and having %d tracepoints", tracepoints_start, tracepoints_count);
 675
 676         return 0;
 677 }
 678
 679 int tracepoint_unregister_lib(struct tracepoint *tracepoints_start, int tracepoints_count)
 680 {
 681         /*FIXME: implement; but before implementing, tracepoint_register_lib must
 682           have appropriate locking. */
 683
 684         return 0;
 685 }