diff options
Diffstat (limited to 'elf/tlsdeschtab.h')
| -rw-r--r-- | elf/tlsdeschtab.h | 164 |
1 files changed, 0 insertions, 164 deletions
diff --git a/elf/tlsdeschtab.h b/elf/tlsdeschtab.h deleted file mode 100644 index 3091d8b420..0000000000 --- a/elf/tlsdeschtab.h +++ /dev/null @@ -1,164 +0,0 @@ -/* Hash table for TLS descriptors. - Copyright (C) 2005-2017 Free Software Foundation, Inc. - This file is part of the GNU C Library. - Contributed by Alexandre Oliva <aoliva@redhat.com> - - The GNU C Library is free software; you can redistribute it and/or - modify it under the terms of the GNU Lesser General Public - License as published by the Free Software Foundation; either - version 2.1 of the License, or (at your option) any later version. - - The GNU C Library is distributed in the hope that it will be useful, - but WITHOUT ANY WARRANTY; without even the implied warranty of - MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU - Lesser General Public License for more details. - - You should have received a copy of the GNU Lesser General Public - License along with the GNU C Library; if not, see - <http://www.gnu.org/licenses/>. */ - -#ifndef TLSDESCHTAB_H -# define TLSDESCHTAB_H 1 - -#include <atomic.h> - -# ifdef SHARED - -# include <inline-hashtab.h> - -inline static int -hash_tlsdesc (void *p) -{ - struct tlsdesc_dynamic_arg *td = p; - - /* We know all entries are for the same module, so ti_offset is the - only distinguishing entry. */ - return td->tlsinfo.ti_offset; -} - -inline static int -eq_tlsdesc (void *p, void *q) -{ - struct tlsdesc_dynamic_arg *tdp = p, *tdq = q; - - return tdp->tlsinfo.ti_offset == tdq->tlsinfo.ti_offset; -} - -inline static size_t -map_generation (struct link_map *map) -{ - size_t idx = map->l_tls_modid; - struct dtv_slotinfo_list *listp = GL(dl_tls_dtv_slotinfo_list); - - /* Find the place in the dtv slotinfo list. */ - do - { - /* Does it fit in the array of this list element? */ - if (idx < listp->len) - { - /* We should never get here for a module in static TLS, so - we can assume that, if the generation count is zero, we - still haven't determined the generation count for this - module. */ - if (listp->slotinfo[idx].map == map && listp->slotinfo[idx].gen) - return listp->slotinfo[idx].gen; - else - break; - } - idx -= listp->len; - listp = listp->next; - } - while (listp != NULL); - - /* If we get to this point, the module still hasn't been assigned an - entry in the dtv slotinfo data structures, and it will when we're - done with relocations. At that point, the module will get a - generation number that is one past the current generation, so - return exactly that. */ - return GL(dl_tls_generation) + 1; -} - -void * -internal_function -_dl_make_tlsdesc_dynamic (struct link_map *map, size_t ti_offset) -{ - struct hashtab *ht; - void **entry; - struct tlsdesc_dynamic_arg *td, test; - - /* FIXME: We could use a per-map lock here, but is it worth it? */ - __rtld_lock_lock_recursive (GL(dl_load_lock)); - - ht = map->l_mach.tlsdesc_table; - if (! ht) - { - ht = htab_create (); - if (! ht) - { - __rtld_lock_unlock_recursive (GL(dl_load_lock)); - return 0; - } - map->l_mach.tlsdesc_table = ht; - } - - test.tlsinfo.ti_module = map->l_tls_modid; - test.tlsinfo.ti_offset = ti_offset; - entry = htab_find_slot (ht, &test, 1, hash_tlsdesc, eq_tlsdesc); - if (! entry) - { - __rtld_lock_unlock_recursive (GL(dl_load_lock)); - return 0; - } - - if (*entry) - { - td = *entry; - __rtld_lock_unlock_recursive (GL(dl_load_lock)); - return td; - } - - *entry = td = malloc (sizeof (struct tlsdesc_dynamic_arg)); - /* This may be higher than the map's generation, but it doesn't - matter much. Worst case, we'll have one extra DTV update per - thread. */ - td->gen_count = map_generation (map); - td->tlsinfo = test.tlsinfo; - - __rtld_lock_unlock_recursive (GL(dl_load_lock)); - return td; -} - -# endif /* SHARED */ - -/* The idea of the following two functions is to stop multiple threads - from attempting to resolve the same TLS descriptor without busy - waiting. Ideally, we should be able to release the lock right - after changing td->entry, and then using say a condition variable - or a futex wake to wake up any waiting threads, but let's try to - avoid introducing such dependencies. */ - -static int -_dl_tlsdesc_resolve_early_return_p (struct tlsdesc volatile *td, void *caller) -{ - if (caller != atomic_load_relaxed (&td->entry)) - return 1; - - __rtld_lock_lock_recursive (GL(dl_load_lock)); - if (caller != atomic_load_relaxed (&td->entry)) - { - __rtld_lock_unlock_recursive (GL(dl_load_lock)); - return 1; - } - - atomic_store_relaxed (&td->entry, _dl_tlsdesc_resolve_hold); - - return 0; -} - -static void -_dl_tlsdesc_wake_up_held_fixups (void) -{ - __rtld_lock_unlock_recursive (GL(dl_load_lock)); -} - -#endif |