libust/tracepoint.c

   1 /*
   2  * Copyright (C) 2008 Mathieu Desnoyers
   3  * Copyright (C) 2009 Pierre-Marc Fournier
   4  *
   5  * This library is free software; you can redistribute it and/or
   6  * modify it under the terms of the GNU Lesser General Public
   7  * License as published by the Free Software Foundation; either
   8  * version 2.1 of the License, or (at your option) any later version.
   9  *
  10  * This library 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 GNU
  13  * Lesser General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU Lesser General Public
  16  * License along with this library; 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 <ust/kernelcompat.h>
  36 #include <ust/tracepoint.h>
  37 #include "usterr.h"
  38 //#include "list.h"
  39
  40 #define _LGPL_SOURCE
  41 #include <urcu-bp.h>
  42
  43 //extern struct tracepoint __start___tracepoints[] __attribute__((visibility("hidden")));
  44 //extern struct tracepoint __stop___tracepoints[] __attribute__((visibility("hidden")));
  45
  46 /* Set to 1 to enable tracepoint debug output */
  47 static const int tracepoint_debug;
  48
  49 /* libraries that contain tracepoints (struct tracepoint_lib) */
  50 static LIST_HEAD(libs);
  51
  52 /*
  53  * tracepoints_mutex nests inside module_mutex. Tracepoints mutex protects the
  54  * builtin and module tracepoints and the hash table.
  55  */
  56 static DEFINE_MUTEX(tracepoints_mutex);
  57
  58 /*
  59  * Tracepoint hash table, containing the active tracepoints.
  60  * Protected by tracepoints_mutex.
  61  */
  62 #define TRACEPOINT_HASH_BITS 6
  63 #define TRACEPOINT_TABLE_SIZE (1 << TRACEPOINT_HASH_BITS)
  64 static struct hlist_head tracepoint_table[TRACEPOINT_TABLE_SIZE];
  65
  66 /*
  67  * Note about RCU :
  68  * It is used to to delay the free of multiple probes array until a quiescent
  69  * state is reached.
  70  * Tracepoint entries modifications are protected by the tracepoints_mutex.
  71  */
  72 struct tracepoint_entry {
  73         struct hlist_node hlist;
  74         void **funcs;
  75         int refcount;   /* Number of times armed. 0 if disarmed. */
  76         char name[0];
  77 };
  78
  79 struct tp_probes {
  80         union {
  81 //ust//         struct rcu_head rcu;
  82                 struct list_head list;
  83         } u;
  84         void *probes[0];
  85 };
  86
  87 static inline void *allocate_probes(int count)
  88 {
  89         struct tp_probes *p  = kmalloc(count * sizeof(void *)
  90                         + sizeof(struct tp_probes), GFP_KERNEL);
  91         return p == NULL ? NULL : p->probes;
  92 }
  93
  94 //ust// static void rcu_free_old_probes(struct rcu_head *head)
  95 //ust// {
  96 //ust//         kfree(container_of(head, struct tp_probes, u.rcu));
  97 //ust// }
  98
  99 static inline void release_probes(void *old)
 100 {
 101         if (old) {
 102                 struct tp_probes *tp_probes = container_of(old,
 103                         struct tp_probes, probes[0]);
 104 //ust//         call_rcu_sched(&tp_probes->u.rcu, rcu_free_old_probes);
 105                 synchronize_rcu();
 106                 kfree(tp_probes);
 107         }
 108 }
 109
 110 static void debug_print_probes(struct tracepoint_entry *entry)
 111 {
 112         int i;
 113
 114         if (!tracepoint_debug || !entry->funcs)
 115                 return;
 116
 117         for (i = 0; entry->funcs[i]; i++)
 118                 printk(KERN_DEBUG "Probe %d : %p\n", i, entry->funcs[i]);
 119 }
 120
 121 static void *
 122 tracepoint_entry_add_probe(struct tracepoint_entry *entry, void *probe)
 123 {
 124         int nr_probes = 0;
 125         void **old, **new;
 126
 127         WARN_ON(!probe);
 128
 129         debug_print_probes(entry);
 130         old = entry->funcs;
 131         if (old) {
 132                 /* (N -> N+1), (N != 0, 1) probes */
 133                 for (nr_probes = 0; old[nr_probes]; nr_probes++)
 134                         if (old[nr_probes] == probe)
 135                                 return ERR_PTR(-EEXIST);
 136         }
 137         /* + 2 : one for new probe, one for NULL func */
 138         new = allocate_probes(nr_probes + 2);
 139         if (new == NULL)
 140                 return ERR_PTR(-ENOMEM);
 141         if (old)
 142                 memcpy(new, old, nr_probes * sizeof(void *));
 143         new[nr_probes] = probe;
 144         new[nr_probes + 1] = NULL;
 145         entry->refcount = nr_probes + 1;
 146         entry->funcs = new;
 147         debug_print_probes(entry);
 148         return old;
 149 }
 150
 151 static void *
 152 tracepoint_entry_remove_probe(struct tracepoint_entry *entry, void *probe)
 153 {
 154         int nr_probes = 0, nr_del = 0, i;
 155         void **old, **new;
 156
 157         old = entry->funcs;
 158
 159         if (!old)
 160                 return ERR_PTR(-ENOENT);
 161
 162         debug_print_probes(entry);
 163         /* (N -> M), (N > 1, M >= 0) probes */
 164         for (nr_probes = 0; old[nr_probes]; nr_probes++) {
 165                 if ((!probe || old[nr_probes] == probe))
 166                         nr_del++;
 167         }
 168
 169         if (nr_probes - nr_del == 0) {
 170                 /* N -> 0, (N > 1) */
 171                 entry->funcs = NULL;
 172                 entry->refcount = 0;
 173                 debug_print_probes(entry);
 174                 return old;
 175         } else {
 176                 int j = 0;
 177                 /* N -> M, (N > 1, M > 0) */
 178                 /* + 1 for NULL */
 179                 new = allocate_probes(nr_probes - nr_del + 1);
 180                 if (new == NULL)
 181                         return ERR_PTR(-ENOMEM);
 182                 for (i = 0; old[i]; i++)
 183                         if ((probe && old[i] != probe))
 184                                 new[j++] = old[i];
 185                 new[nr_probes - nr_del] = NULL;
 186                 entry->refcount = nr_probes - nr_del;
 187                 entry->funcs = new;
 188         }
 189         debug_print_probes(entry);
 190         return old;
 191 }
 192
 193 /*
 194  * Get tracepoint if the tracepoint is present in the tracepoint hash table.
 195  * Must be called with tracepoints_mutex held.
 196  * Returns NULL if not present.
 197  */
 198 static struct tracepoint_entry *get_tracepoint(const char *name)
 199 {
 200         struct hlist_head *head;
 201         struct hlist_node *node;
 202         struct tracepoint_entry *e;
 203         u32 hash = jhash(name, strlen(name), 0);
 204
 205         head = &tracepoint_table[hash & (TRACEPOINT_TABLE_SIZE - 1)];
 206         hlist_for_each_entry(e, node, head, hlist) {
 207                 if (!strcmp(name, e->name))
 208                         return e;
 209         }
 210         return NULL;
 211 }
 212
 213 /*
 214  * Add the tracepoint to the tracepoint hash table. Must be called with
 215  * tracepoints_mutex held.
 216  */
 217 static struct tracepoint_entry *add_tracepoint(const char *name)
 218 {
 219         struct hlist_head *head;
 220         struct hlist_node *node;
 221         struct tracepoint_entry *e;
 222         size_t name_len = strlen(name) + 1;
 223         u32 hash = jhash(name, name_len-1, 0);
 224
 225         head = &tracepoint_table[hash & (TRACEPOINT_TABLE_SIZE - 1)];
 226         hlist_for_each_entry(e, node, head, hlist) {
 227                 if (!strcmp(name, e->name)) {
 228                         printk(KERN_NOTICE
 229                                 "tracepoint %s busy\n", name);
 230                         return ERR_PTR(-EEXIST);        /* Already there */
 231                 }
 232         }
 233         /*
 234          * Using kmalloc here to allocate a variable length element. Could
 235          * cause some memory fragmentation if overused.
 236          */
 237         e = kmalloc(sizeof(struct tracepoint_entry) + name_len, GFP_KERNEL);
 238         if (!e)
 239                 return ERR_PTR(-ENOMEM);
 240         memcpy(&e->name[0], name, name_len);
 241         e->funcs = NULL;
 242         e->refcount = 0;
 243         hlist_add_head(&e->hlist, head);
 244         return e;
 245 }
 246
 247 /*
 248  * Remove the tracepoint from the tracepoint hash table. Must be called with
 249  * mutex_lock held.
 250  */
 251 static inline void remove_tracepoint(struct tracepoint_entry *e)
 252 {
 253         hlist_del(&e->hlist);
 254         kfree(e);
 255 }
 256
 257 /*
 258  * Sets the probe callback corresponding to one tracepoint.
 259  */
 260 static void set_tracepoint(struct tracepoint_entry **entry,
 261         struct tracepoint *elem, int active)
 262 {
 263         WARN_ON(strcmp((*entry)->name, elem->name) != 0);
 264
 265         /*
 266          * rcu_assign_pointer has a smp_wmb() which makes sure that the new
 267          * probe callbacks array is consistent before setting a pointer to it.
 268          * This array is referenced by __DO_TRACE from
 269          * include/linux/tracepoints.h. A matching smp_read_barrier_depends()
 270          * is used.
 271          */
 272         rcu_assign_pointer(elem->funcs, (*entry)->funcs);
 273         elem->state__imv = active;
 274 }
 275
 276 /*
 277  * Disable a tracepoint and its probe callback.
 278  * Note: only waiting an RCU period after setting elem->call to the empty
 279  * function insures that the original callback is not used anymore. This insured
 280  * by preempt_disable around the call site.
 281  */
 282 static void disable_tracepoint(struct tracepoint *elem)
 283 {
 284         elem->state__imv = 0;
 285         rcu_assign_pointer(elem->funcs, NULL);
 286 }
 287
 288 /**
 289  * tracepoint_update_probe_range - Update a probe range
 290  * @begin: beginning of the range
 291  * @end: end of the range
 292  *
 293  * Updates the probe callback corresponding to a range of tracepoints.
 294  */
 295 void tracepoint_update_probe_range(struct tracepoint *begin,
 296         struct tracepoint *end)
 297 {
 298         struct tracepoint *iter;
 299         struct tracepoint_entry *mark_entry;
 300
 301         mutex_lock(&tracepoints_mutex);
 302         for (iter = begin; iter < end; iter++) {
 303                 mark_entry = get_tracepoint(iter->name);
 304                 if (mark_entry) {
 305                         set_tracepoint(&mark_entry, iter,
 306                                         !!mark_entry->refcount);
 307                 } else {
 308                         disable_tracepoint(iter);
 309                 }
 310         }
 311         mutex_unlock(&tracepoints_mutex);
 312 }
 313
 314 static void lib_update_tracepoints(void)
 315 {
 316         struct tracepoint_lib *lib;
 317
 318 //ust// mutex_lock(&module_mutex);
 319         list_for_each_entry(lib, &libs, list)
 320                 tracepoint_update_probe_range(lib->tracepoints_start,
 321                                 lib->tracepoints_start + lib->tracepoints_count);
 322 //ust// mutex_unlock(&module_mutex);
 323 }
 324
 325 /*
 326  * Update probes, removing the faulty probes.
 327  */
 328 static void tracepoint_update_probes(void)
 329 {
 330         /* Core kernel tracepoints */
 331 //ust// tracepoint_update_probe_range(__start___tracepoints,
 332 //ust//         __stop___tracepoints);
 333         /* tracepoints in modules. */
 334         lib_update_tracepoints();
 335         /* Update immediate values */
 336         core_imv_update();
 337 //ust// module_imv_update();
 338 }
 339
 340 static void *tracepoint_add_probe(const char *name, void *probe)
 341 {
 342         struct tracepoint_entry *entry;
 343         void *old;
 344
 345         entry = get_tracepoint(name);
 346         if (!entry) {
 347                 entry = add_tracepoint(name);
 348                 if (IS_ERR(entry))
 349                         return entry;
 350         }
 351         old = tracepoint_entry_add_probe(entry, probe);
 352         if (IS_ERR(old) && !entry->refcount)
 353                 remove_tracepoint(entry);
 354         return old;
 355 }
 356
 357 /**
 358  * tracepoint_probe_register -  Connect a probe to a tracepoint
 359  * @name: tracepoint name
 360  * @probe: probe handler
 361  *
 362  * Returns 0 if ok, error value on error.
 363  * The probe address must at least be aligned on the architecture pointer size.
 364  */
 365 int tracepoint_probe_register(const char *name, void *probe)
 366 {
 367         void *old;
 368
 369         mutex_lock(&tracepoints_mutex);
 370         old = tracepoint_add_probe(name, probe);
 371         mutex_unlock(&tracepoints_mutex);
 372         if (IS_ERR(old))
 373                 return PTR_ERR(old);
 374
 375         tracepoint_update_probes();             /* may update entry */
 376         release_probes(old);
 377         return 0;
 378 }
 379 //ust// EXPORT_SYMBOL_GPL(tracepoint_probe_register);
 380
 381 static void *tracepoint_remove_probe(const char *name, void *probe)
 382 {
 383         struct tracepoint_entry *entry;
 384         void *old;
 385
 386         entry = get_tracepoint(name);
 387         if (!entry)
 388                 return ERR_PTR(-ENOENT);
 389         old = tracepoint_entry_remove_probe(entry, probe);
 390         if (IS_ERR(old))
 391                 return old;
 392         if (!entry->refcount)
 393                 remove_tracepoint(entry);
 394         return old;
 395 }
 396
 397 /**
 398  * tracepoint_probe_unregister -  Disconnect a probe from a tracepoint
 399  * @name: tracepoint name
 400  * @probe: probe function pointer
 401  *
 402  * We do not need to call a synchronize_sched to make sure the probes have
 403  * finished running before doing a module unload, because the module unload
 404  * itself uses stop_machine(), which insures that every preempt disabled section
 405  * have finished.
 406  */
 407 int tracepoint_probe_unregister(const char *name, void *probe)
 408 {
 409         void *old;
 410
 411         mutex_lock(&tracepoints_mutex);
 412         old = tracepoint_remove_probe(name, probe);
 413         mutex_unlock(&tracepoints_mutex);
 414         if (IS_ERR(old))
 415                 return PTR_ERR(old);
 416
 417         tracepoint_update_probes();             /* may update entry */
 418         release_probes(old);
 419         return 0;
 420 }
 421 //ust// EXPORT_SYMBOL_GPL(tracepoint_probe_unregister);
 422
 423 static LIST_HEAD(old_probes);
 424 static int need_update;
 425
 426 static void tracepoint_add_old_probes(void *old)
 427 {
 428         need_update = 1;
 429         if (old) {
 430                 struct tp_probes *tp_probes = container_of(old,
 431                         struct tp_probes, probes[0]);
 432                 list_add(&tp_probes->u.list, &old_probes);
 433         }
 434 }
 435
 436 /**
 437  * tracepoint_probe_register_noupdate -  register a probe but not connect
 438  * @name: tracepoint name
 439  * @probe: probe handler
 440  *
 441  * caller must call tracepoint_probe_update_all()
 442  */
 443 int tracepoint_probe_register_noupdate(const char *name, void *probe)
 444 {
 445         void *old;
 446
 447         mutex_lock(&tracepoints_mutex);
 448         old = tracepoint_add_probe(name, probe);
 449         if (IS_ERR(old)) {
 450                 mutex_unlock(&tracepoints_mutex);
 451                 return PTR_ERR(old);
 452         }
 453         tracepoint_add_old_probes(old);
 454         mutex_unlock(&tracepoints_mutex);
 455         return 0;
 456 }
 457 //ust// EXPORT_SYMBOL_GPL(tracepoint_probe_register_noupdate);
 458
 459 /**
 460  * tracepoint_probe_unregister_noupdate -  remove a probe but not disconnect
 461  * @name: tracepoint name
 462  * @probe: probe function pointer
 463  *
 464  * caller must call tracepoint_probe_update_all()
 465  */
 466 int tracepoint_probe_unregister_noupdate(const char *name, void *probe)
 467 {
 468         void *old;
 469
 470         mutex_lock(&tracepoints_mutex);
 471         old = tracepoint_remove_probe(name, probe);
 472         if (IS_ERR(old)) {
 473                 mutex_unlock(&tracepoints_mutex);
 474                 return PTR_ERR(old);
 475         }
 476         tracepoint_add_old_probes(old);
 477         mutex_unlock(&tracepoints_mutex);
 478         return 0;
 479 }
 480 //ust// EXPORT_SYMBOL_GPL(tracepoint_probe_unregister_noupdate);
 481
 482 /**
 483  * tracepoint_probe_update_all -  update tracepoints
 484  */
 485 void tracepoint_probe_update_all(void)
 486 {
 487         LIST_HEAD(release_probes);
 488         struct tp_probes *pos, *next;
 489
 490         mutex_lock(&tracepoints_mutex);
 491         if (!need_update) {
 492                 mutex_unlock(&tracepoints_mutex);
 493                 return;
 494         }
 495         if (!list_empty(&old_probes))
 496                 list_replace_init(&old_probes, &release_probes);
 497         need_update = 0;
 498         mutex_unlock(&tracepoints_mutex);
 499
 500         tracepoint_update_probes();
 501         list_for_each_entry_safe(pos, next, &release_probes, u.list) {
 502                 list_del(&pos->u.list);
 503 //ust//         call_rcu_sched(&pos->u.rcu, rcu_free_old_probes);
 504                 synchronize_rcu();
 505                 kfree(pos);
 506         }
 507 }
 508 //ust// EXPORT_SYMBOL_GPL(tracepoint_probe_update_all);
 509
 510 /*
 511  * Returns 0 if current not found.
 512  * Returns 1 if current found.
 513  */
 514 int lib_get_iter_tracepoints(struct tracepoint_iter *iter)
 515 {
 516         struct tracepoint_lib *iter_lib;
 517         int found = 0;
 518
 519 //ust// mutex_lock(&module_mutex);
 520         list_for_each_entry(iter_lib, &libs, list) {
 521                 if (iter_lib < iter->lib)
 522                         continue;
 523                 else if (iter_lib > iter->lib)
 524                         iter->tracepoint = NULL;
 525                 found = tracepoint_get_iter_range(&iter->tracepoint,
 526                         iter_lib->tracepoints_start,
 527                         iter_lib->tracepoints_start + iter_lib->tracepoints_count);
 528                 if (found) {
 529                         iter->lib = iter_lib;
 530                         break;
 531                 }
 532         }
 533 //ust// mutex_unlock(&module_mutex);
 534         return found;
 535 }
 536
 537 /**
 538  * tracepoint_get_iter_range - Get a next tracepoint iterator given a range.
 539  * @tracepoint: current tracepoints (in), next tracepoint (out)
 540  * @begin: beginning of the range
 541  * @end: end of the range
 542  *
 543  * Returns whether a next tracepoint has been found (1) or not (0).
 544  * Will return the first tracepoint in the range if the input tracepoint is
 545  * NULL.
 546  */
 547 int tracepoint_get_iter_range(struct tracepoint **tracepoint,
 548         struct tracepoint *begin, struct tracepoint *end)
 549 {
 550         if (!*tracepoint && begin != end) {
 551                 *tracepoint = begin;
 552                 return 1;
 553         }
 554         if (*tracepoint >= begin && *tracepoint < end)
 555                 return 1;
 556         return 0;
 557 }
 558 //ust// EXPORT_SYMBOL_GPL(tracepoint_get_iter_range);
 559
 560 static void tracepoint_get_iter(struct tracepoint_iter *iter)
 561 {
 562         int found = 0;
 563
 564 //ust// /* Core kernel tracepoints */
 565 //ust// if (!iter->module) {
 566 //ust//         found = tracepoint_get_iter_range(&iter->tracepoint,
 567 //ust//                         __start___tracepoints, __stop___tracepoints);
 568 //ust//         if (found)
 569 //ust//                 goto end;
 570 //ust// }
 571         /* tracepoints in libs. */
 572         found = lib_get_iter_tracepoints(iter);
 573 //ust// end:
 574         if (!found)
 575                 tracepoint_iter_reset(iter);
 576 }
 577
 578 void tracepoint_iter_start(struct tracepoint_iter *iter)
 579 {
 580         tracepoint_get_iter(iter);
 581 }
 582 //ust// EXPORT_SYMBOL_GPL(tracepoint_iter_start);
 583
 584 void tracepoint_iter_next(struct tracepoint_iter *iter)
 585 {
 586         iter->tracepoint++;
 587         /*
 588          * iter->tracepoint may be invalid because we blindly incremented it.
 589          * Make sure it is valid by marshalling on the tracepoints, getting the
 590          * tracepoints from following modules if necessary.
 591          */
 592         tracepoint_get_iter(iter);
 593 }
 594 //ust// EXPORT_SYMBOL_GPL(tracepoint_iter_next);
 595
 596 void tracepoint_iter_stop(struct tracepoint_iter *iter)
 597 {
 598 }
 599 //ust// EXPORT_SYMBOL_GPL(tracepoint_iter_stop);
 600
 601 void tracepoint_iter_reset(struct tracepoint_iter *iter)
 602 {
 603 //ust// iter->module = NULL;
 604         iter->tracepoint = NULL;
 605 }
 606 //ust// EXPORT_SYMBOL_GPL(tracepoint_iter_reset);
 607
 608 //ust// #ifdef CONFIG_MODULES
 609
 610 //ust// int tracepoint_module_notify(struct notifier_block *self,
 611 //ust//                              unsigned long val, void *data)
 612 //ust// {
 613 //ust//         struct module *mod = data;
 614 //ust//
 615 //ust//         switch (val) {
 616 //ust//         case MODULE_STATE_COMING:
 617 //ust//                 tracepoint_update_probe_range(mod->tracepoints,
 618 //ust//                         mod->tracepoints + mod->num_tracepoints);
 619 //ust//                 break;
 620 //ust//         case MODULE_STATE_GOING:
 621 //ust//                 tracepoint_update_probe_range(mod->tracepoints,
 622 //ust//                         mod->tracepoints + mod->num_tracepoints);
 623 //ust//                 break;
 624 //ust//         }
 625 //ust//         return 0;
 626 //ust// }
 627
 628 //ust// struct notifier_block tracepoint_module_nb = {
 629 //ust//         .notifier_call = tracepoint_module_notify,
 630 //ust//         .priority = 0,
 631 //ust// };
 632
 633 //ust// static int init_tracepoints(void)
 634 //ust// {
 635 //ust//         return register_module_notifier(&tracepoint_module_nb);
 636 //ust// }
 637 //ust// __initcall(init_tracepoints);
 638
 639 //ust// #endif /* CONFIG_MODULES */
 640
 641 static void (*new_tracepoint_cb)(struct tracepoint *) = NULL;
 642
 643 void tracepoint_set_new_tracepoint_cb(void (*cb)(struct tracepoint *))
 644 {
 645         new_tracepoint_cb = cb;
 646 }
 647
 648 static void new_tracepoints(struct tracepoint *start, struct tracepoint *end)
 649 {
 650         if(new_tracepoint_cb) {
 651                 struct tracepoint *t;
 652                 for(t=start; t < end; t++) {
 653                         new_tracepoint_cb(t);
 654                 }
 655         }
 656 }
 657
 658 int tracepoint_register_lib(struct tracepoint *tracepoints_start, int tracepoints_count)
 659 {
 660         struct tracepoint_lib *pl;
 661
 662         pl = (struct tracepoint_lib *) malloc(sizeof(struct tracepoint_lib));
 663
 664         pl->tracepoints_start = tracepoints_start;
 665         pl->tracepoints_count = tracepoints_count;
 666
 667         /* FIXME: maybe protect this with its own mutex? */
 668         mutex_lock(&tracepoints_mutex);
 669         list_add(&pl->list, &libs);
 670         mutex_unlock(&tracepoints_mutex);
 671
 672         new_tracepoints(tracepoints_start, tracepoints_start + tracepoints_count);
 673
 674         /* FIXME: update just the loaded lib */
 675         lib_update_tracepoints();
 676
 677         DBG("just registered a tracepoints section from %p and having %d tracepoints", tracepoints_start, tracepoints_count);
 678
 679         return 0;
 680 }
 681
 682 int tracepoint_unregister_lib(struct tracepoint *tracepoints_start, int tracepoints_count)
 683 {
 684         /*FIXME: implement; but before implementing, tracepoint_register_lib must
 685           have appropriate locking. */
 686
 687         return 0;
 688 }