1/* Copyright (C) 2002-2023 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 void * p__ __asm__(RSP_REG); \
46 asm volatile("" : "=r" (p__)); \
47 p__; })
48#else
49# define CURRENT_STACK_FRAME __builtin_frame_address (0)
50#endif
51