1 /* Copyright (C) 2002-2022 Free Software Foundation, Inc. 2 This file is part of the GNU C Library. 3 4 The GNU C Library is free software; you can redistribute it and/or 5 modify it under the terms of the GNU Lesser General Public 6 License as published by the Free Software Foundation; either 7 version 2.1 of the License, or (at your option) any later version. 8 9 The GNU C Library is distributed in the hope that it will be useful, 10 but WITHOUT ANY WARRANTY; without even the implied warranty of 11 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 12 Lesser General Public License for more details. 13 14 You should have received a copy of the GNU Lesser General Public 15 License along with the GNU C Library; if not, see 16 <https://www.gnu.org/licenses/>. */ 17 18 /* Default stack size. */ 19 #define ARCH_STACK_DEFAULT_SIZE (2 * 1024 * 1024) 20 21 /* Minimum guard size. */ 22 #define ARCH_MIN_GUARD_SIZE 0 23 24 /* Required stack pointer alignment at beginning. SSE requires 16 25 bytes. */ 26 #define STACK_ALIGN 16 27 28 /* Minimal stack size after allocating thread descriptor and guard size. */ 29 #define MINIMAL_REST_STACK 2048 30 31 /* Alignment requirement for TCB. 32 33 Some processors such as Intel Atom pay a big penalty on every 34 access using a segment override if that segment's base is not 35 aligned to the size of a cache line. (See Intel 64 and IA-32 36 Architectures Optimization Reference Manual, section 13.3.3.3, 37 "Segment Base".) On such machines, a cache line is 64 bytes. */ 38 #define TCB_ALIGNMENT 64 39 40 41 /* Location of current stack frame. */ 42 #ifdef __x86_64__ 43 /* The frame pointer is not usable. */ 44 # define CURRENT_STACK_FRAME \ 45 ({ register char *frame __asm__("rsp"); frame; }) 46 #else 47 # define CURRENT_STACK_FRAME __builtin_frame_address (0) 48 #endif 49