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/* Pointer guard implementation. AArch64 version.
Copyright (C) 2014-2023 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/>. */
#ifndef POINTER_GUARD_H
#define POINTER_GUARD_H
/* Pointer mangling is supported for AArch64. */
#if (IS_IN (rtld) \
|| (!defined SHARED && (IS_IN (libc) \
|| IS_IN (libpthread))))
# ifdef __ASSEMBLER__
/* Note, dst, src, guard, and tmp are all register numbers rather than
register names so they will work with both ILP32 and LP64. */
# define PTR_MANGLE(dst, src, guard, tmp) \
LDST_PCREL (ldr, guard, tmp, C_SYMBOL_NAME(__pointer_chk_guard_local)); \
PTR_MANGLE2 (dst, src, guard)
/* Use PTR_MANGLE2 for efficiency if guard is already loaded. */
# define PTR_MANGLE2(dst, src, guard)\
eor x##dst, x##src, x##guard
# define PTR_DEMANGLE(dst, src, guard, tmp)\
PTR_MANGLE (dst, src, guard, tmp)
# define PTR_DEMANGLE2(dst, src, guard)\
PTR_MANGLE2 (dst, src, guard)
# else
extern uintptr_t __pointer_chk_guard_local attribute_relro attribute_hidden;
# define PTR_MANGLE(var) \
(var) = (__typeof (var)) ((uintptr_t) (var) ^ __pointer_chk_guard_local)
# define PTR_DEMANGLE(var) PTR_MANGLE (var)
# endif
#else
# ifdef __ASSEMBLER__
/* Note, dst, src, guard, and tmp are all register numbers rather than
register names so they will work with both ILP32 and LP64. */
# define PTR_MANGLE(dst, src, guard, tmp) \
LDST_GLOBAL (ldr, guard, tmp, C_SYMBOL_NAME(__pointer_chk_guard)); \
PTR_MANGLE2 (dst, src, guard)
/* Use PTR_MANGLE2 for efficiency if guard is already loaded. */
# define PTR_MANGLE2(dst, src, guard)\
eor x##dst, x##src, x##guard
# define PTR_DEMANGLE(dst, src, guard, tmp)\
PTR_MANGLE (dst, src, guard, tmp)
# define PTR_DEMANGLE2(dst, src, guard)\
PTR_MANGLE2 (dst, src, guard)
# else
# include <stdint.h>
extern uintptr_t __pointer_chk_guard attribute_relro;
# define PTR_MANGLE(var) \
(var) = (__typeof (var)) ((uintptr_t) (var) ^ __pointer_chk_guard)
# define PTR_DEMANGLE(var) PTR_MANGLE (var)
# endif
#endif
#endif /* POINTER_GUARD_H */
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