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- /* Copyright (C) 2001-2026 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
- <https://www.gnu.org/licenses/>. */
- /* This file contains a bit of information about the stack allocation
- of the processor. */
- #ifndef _STACKINFO_H
- #define _STACKINFO_H 1
- #include <elf.h>
- #ifdef __ILP32__
- # define RSP_REG "esp"
- #else
- # define RSP_REG "rsp"
- #endif
- /* On x86_64 the stack grows down. */
- #define _STACK_GROWS_DOWN 1
- /* Default to an executable stack. PROT_EXEC can be overridden if PT_GNU_STACK
- * is present, but it is presumed absent. */
- #define DEFAULT_STACK_PROT_PERMS (PROT_READ|PROT_WRITE|PROT_EXEC)
- /* Access to the stack pointer. The macros are used in alloca_account
- for which they need to act as barriers as well, hence the additional
- (unnecessary) parameters. */
- #define stackinfo_get_sp() \
- ({ register void * p__ __asm__(RSP_REG); \
- asm volatile("" : "=r" (p__)); \
- p__; })
- #define stackinfo_sub_sp(ptr) \
- ({ ptrdiff_t d__; \
- asm volatile ("sub %%" RSP_REG " , %0" : "=r" (d__) : "0" (ptr)); \
- d__; })
- #endif /* stackinfo.h */
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