diff options
Diffstat (limited to 'sysdeps/i386/tlsdesc.c')
| -rw-r--r-- | sysdeps/i386/tlsdesc.c | 268 |
1 files changed, 0 insertions, 268 deletions
diff --git a/sysdeps/i386/tlsdesc.c b/sysdeps/i386/tlsdesc.c deleted file mode 100644 index 90de2bb05e..0000000000 --- a/sysdeps/i386/tlsdesc.c +++ /dev/null @@ -1,268 +0,0 @@ -/* Manage TLS descriptors. i386 version. - Copyright (C) 2005-2017 Free Software Foundation, Inc. - This file is part of the GNU C Library. - - 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/>. */ - -#include <link.h> -#include <ldsodefs.h> -#include <elf/dynamic-link.h> -#include <tls.h> -#include <dl-tlsdesc.h> -#include <dl-unmap-segments.h> -#include <tlsdeschtab.h> - -/* The following 4 functions take an entry_check_offset argument. - It's computed by the caller as an offset between its entry point - and the call site, such that by adding the built-in return address - that is implicitly passed to the function with this offset, we can - easily obtain the caller's entry point to compare with the entry - point given in the TLS descriptor. If it's changed, we want to - return immediately. */ - -/* This function is used to lazily resolve TLS_DESC REL relocations - that reference the *ABS* segment in their own link maps. The - argument is the addend originally stored there. */ - -void -__attribute__ ((regparm (3))) attribute_hidden -_dl_tlsdesc_resolve_abs_plus_addend_fixup (struct tlsdesc volatile *td, - struct link_map *l, - ptrdiff_t entry_check_offset) -{ - ptrdiff_t addend = (ptrdiff_t) td->arg; - - if (_dl_tlsdesc_resolve_early_return_p (td, __builtin_return_address (0) - - entry_check_offset)) - return; - -#ifndef SHARED - CHECK_STATIC_TLS (l, l); -#else - if (!TRY_STATIC_TLS (l, l)) - { - td->arg = _dl_make_tlsdesc_dynamic (l, addend); - td->entry = _dl_tlsdesc_dynamic; - } - else -#endif - { - td->arg = (void*) (addend - l->l_tls_offset); - td->entry = _dl_tlsdesc_return; - } - - _dl_tlsdesc_wake_up_held_fixups (); -} - -/* This function is used to lazily resolve TLS_DESC REL relocations - that originally had zero addends. The argument location, that - originally held the addend, is used to hold a pointer to the - relocation, but it has to be restored before we call the function - that applies relocations. */ - -void -__attribute__ ((regparm (3))) attribute_hidden -_dl_tlsdesc_resolve_rel_fixup (struct tlsdesc volatile *td, - struct link_map *l, - ptrdiff_t entry_check_offset) -{ - const ElfW(Rel) *reloc = td->arg; - - if (_dl_tlsdesc_resolve_early_return_p (td, __builtin_return_address (0) - - entry_check_offset)) - return; - - /* The code below was borrowed from _dl_fixup(), - except for checking for STB_LOCAL. */ - const ElfW(Sym) *const symtab - = (const void *) D_PTR (l, l_info[DT_SYMTAB]); - const char *strtab = (const void *) D_PTR (l, l_info[DT_STRTAB]); - const ElfW(Sym) *sym = &symtab[ELFW(R_SYM) (reloc->r_info)]; - lookup_t result; - - /* Look up the target symbol. If the normal lookup rules are not - used don't look in the global scope. */ - if (ELFW(ST_BIND) (sym->st_info) != STB_LOCAL - && __builtin_expect (ELFW(ST_VISIBILITY) (sym->st_other), 0) == 0) - { - const struct r_found_version *version = NULL; - - if (l->l_info[VERSYMIDX (DT_VERSYM)] != NULL) - { - const ElfW(Half) *vernum = - (const void *) D_PTR (l, l_info[VERSYMIDX (DT_VERSYM)]); - ElfW(Half) ndx = vernum[ELFW(R_SYM) (reloc->r_info)] & 0x7fff; - version = &l->l_versions[ndx]; - if (version->hash == 0) - version = NULL; - } - - result = _dl_lookup_symbol_x (strtab + sym->st_name, l, &sym, - l->l_scope, version, ELF_RTYPE_CLASS_PLT, - DL_LOOKUP_ADD_DEPENDENCY, NULL); - } - else - { - /* We already found the symbol. The module (and therefore its load - address) is also known. */ - result = l; - } - - if (!sym) - { - td->arg = 0; - td->entry = _dl_tlsdesc_undefweak; - } - else - { -# ifndef SHARED - CHECK_STATIC_TLS (l, result); -# else - if (!TRY_STATIC_TLS (l, result)) - { - td->arg = _dl_make_tlsdesc_dynamic (result, sym->st_value); - td->entry = _dl_tlsdesc_dynamic; - } - else -# endif - { - td->arg = (void*)(sym->st_value - result->l_tls_offset); - td->entry = _dl_tlsdesc_return; - } - } - - _dl_tlsdesc_wake_up_held_fixups (); -} - -/* This function is used to lazily resolve TLS_DESC RELA relocations. - The argument location is used to hold a pointer to the relocation. */ - -void -__attribute__ ((regparm (3))) attribute_hidden -_dl_tlsdesc_resolve_rela_fixup (struct tlsdesc volatile *td, - struct link_map *l, - ptrdiff_t entry_check_offset) -{ - const ElfW(Rela) *reloc = td->arg; - - if (_dl_tlsdesc_resolve_early_return_p (td, __builtin_return_address (0) - - entry_check_offset)) - return; - - /* The code below was borrowed from _dl_fixup(), - except for checking for STB_LOCAL. */ - const ElfW(Sym) *const symtab - = (const void *) D_PTR (l, l_info[DT_SYMTAB]); - const char *strtab = (const void *) D_PTR (l, l_info[DT_STRTAB]); - const ElfW(Sym) *sym = &symtab[ELFW(R_SYM) (reloc->r_info)]; - lookup_t result; - - /* Look up the target symbol. If the normal lookup rules are not - used don't look in the global scope. */ - if (ELFW(ST_BIND) (sym->st_info) != STB_LOCAL - && __builtin_expect (ELFW(ST_VISIBILITY) (sym->st_other), 0) == 0) - { - const struct r_found_version *version = NULL; - - if (l->l_info[VERSYMIDX (DT_VERSYM)] != NULL) - { - const ElfW(Half) *vernum = - (const void *) D_PTR (l, l_info[VERSYMIDX (DT_VERSYM)]); - ElfW(Half) ndx = vernum[ELFW(R_SYM) (reloc->r_info)] & 0x7fff; - version = &l->l_versions[ndx]; - if (version->hash == 0) - version = NULL; - } - - result = _dl_lookup_symbol_x (strtab + sym->st_name, l, &sym, - l->l_scope, version, ELF_RTYPE_CLASS_PLT, - DL_LOOKUP_ADD_DEPENDENCY, NULL); - } - else - { - /* We already found the symbol. The module (and therefore its load - address) is also known. */ - result = l; - } - - if (!sym) - { - td->arg = (void*) reloc->r_addend; - td->entry = _dl_tlsdesc_undefweak; - } - else - { -# ifndef SHARED - CHECK_STATIC_TLS (l, result); -# else - if (!TRY_STATIC_TLS (l, result)) - { - td->arg = _dl_make_tlsdesc_dynamic (result, sym->st_value - + reloc->r_addend); - td->entry = _dl_tlsdesc_dynamic; - } - else -# endif - { - td->arg = (void*) (sym->st_value - result->l_tls_offset - + reloc->r_addend); - td->entry = _dl_tlsdesc_return; - } - } - - _dl_tlsdesc_wake_up_held_fixups (); -} - -/* This function is used to avoid busy waiting for other threads to - complete the lazy relocation. Once another thread wins the race to - relocate a TLS descriptor, it sets the descriptor up such that this - function is called to wait until the resolver releases the - lock. */ - -void -__attribute__ ((regparm (3))) attribute_hidden -_dl_tlsdesc_resolve_hold_fixup (struct tlsdesc volatile *td, - struct link_map *l __attribute__((__unused__)), - ptrdiff_t entry_check_offset) -{ - /* Maybe we're lucky and can return early. */ - if (__builtin_return_address (0) - entry_check_offset != td->entry) - return; - - /* Locking here will stop execution until the running resolver runs - _dl_tlsdesc_wake_up_held_fixups(), releasing the lock. - - FIXME: We'd be better off waiting on a condition variable, such - that we didn't have to hold the lock throughout the relocation - processing. */ - __rtld_lock_lock_recursive (GL(dl_load_lock)); - __rtld_lock_unlock_recursive (GL(dl_load_lock)); -} - - -/* Unmap the dynamic object, but also release its TLS descriptor table - if there is one. */ - -void -internal_function -_dl_unmap (struct link_map *map) -{ - _dl_unmap_segments (map); - -#ifdef SHARED - if (map->l_mach.tlsdesc_table) - htab_delete (map->l_mach.tlsdesc_table); -#endif -} |