1 /* Inline functions for dynamic linking. 2 Copyright (C) 1995-2021 Free Software Foundation, Inc. 3 This file is part of the GNU C Library. 4 5 The GNU C 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 The GNU C 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 the GNU C Library; if not, see 17 <https://www.gnu.org/licenses/>. */ 18 19 #ifndef _DL_STATIC_TLS_H 20 #define _DL_STATIC_TLS_H 21 22 /* This macro is used as a callback from elf_machine_rel{a,} when a 23 static TLS reloc is about to be performed. Since (in dl-load.c) we 24 permit dynamic loading of objects that might use such relocs, we 25 have to check whether each use is actually doable. If the object 26 whose TLS segment the reference resolves to was allocated space in 27 the static TLS block at startup, then it's ok. Otherwise, we make 28 an attempt to allocate it in surplus space on the fly. If that 29 can't be done, we fall back to the error that DF_STATIC_TLS is 30 intended to produce. */ 31 #define HAVE_STATIC_TLS(map, sym_map) \ 32 (__builtin_expect ((sym_map)->l_tls_offset != NO_TLS_OFFSET \ 33 && ((sym_map)->l_tls_offset \ 34 != FORCED_DYNAMIC_TLS_OFFSET), 1)) 35 36 #define CHECK_STATIC_TLS(map, sym_map) \ 37 do { \ 38 if (!HAVE_STATIC_TLS (map, sym_map)) \ 39 _dl_allocate_static_tls (sym_map); \ 40 } while (0) 41 42 #define TRY_STATIC_TLS(map, sym_map) \ 43 (__builtin_expect ((sym_map)->l_tls_offset \ 44 != FORCED_DYNAMIC_TLS_OFFSET, 1) \ 45 && (__builtin_expect ((sym_map)->l_tls_offset != NO_TLS_OFFSET, 1) \ 46 || _dl_try_allocate_static_tls (sym_map, true) == 0)) 47 48 int _dl_try_allocate_static_tls (struct link_map *map, bool optional) 49 attribute_hidden; 50 51 #endif 52