sysdeps/x86/nptl/pthreaddef.h

   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