1/* Pointer obfuscation implenentation. x86-64 version.
2 Copyright (C) 2005-2023 Free Software Foundation, Inc.
3 This file is part of the GNU C Library.
4
5 The GNU C Library is free software; you can redistribute it and/or
6 modify it under the terms of the GNU Lesser General Public
7 License as published by the Free Software Foundation; either
8 version 2.1 of the License, or (at your option) any later version.
9
10 The GNU C Library is distributed in the hope that it will be useful,
11 but WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 Lesser General Public License for more details.
14
15 You should have received a copy of the GNU Lesser General Public
16 License along with the GNU C Library; if not, see
17 <https://www.gnu.org/licenses/>. */
18
19#ifndef POINTER_GUARD_H
20#define POINTER_GUARD_H
21
22#include <x86-lp_size.h>
23#include <tcb-offsets.h>
24
25#if IS_IN (rtld)
26/* We cannot use the thread descriptor because in ld.so we use setjmp
27 earlier than the descriptor is initialized. */
28# ifdef __ASSEMBLER__
29# define PTR_MANGLE(reg) xor __pointer_chk_guard_local(%rip), reg; \
30 rol $2*LP_SIZE+1, reg
31# define PTR_DEMANGLE(reg) ror $2*LP_SIZE+1, reg; \
32 xor __pointer_chk_guard_local(%rip), reg
33# else
34# define PTR_MANGLE(reg) asm ("xor __pointer_chk_guard_local(%%rip), %0\n" \
35 "rol $2*" LP_SIZE "+1, %0" \
36 : "=r" (reg) : "0" (reg))
37# define PTR_DEMANGLE(reg) asm ("ror $2*" LP_SIZE "+1, %0\n" \
38 "xor __pointer_chk_guard_local(%%rip), %0" \
39 : "=r" (reg) : "0" (reg))
40# endif
41#else
42# ifdef __ASSEMBLER__
43# define PTR_MANGLE(reg) xor %fs:POINTER_GUARD, reg; \
44 rol $2*LP_SIZE+1, reg
45# define PTR_DEMANGLE(reg) ror $2*LP_SIZE+1, reg; \
46 xor %fs:POINTER_GUARD, reg
47# else
48# define PTR_MANGLE(var) asm ("xor %%fs:%c2, %0\n" \
49 "rol $2*" LP_SIZE "+1, %0" \
50 : "=r" (var) \
51 : "0" (var), \
52 "i" (POINTER_GUARD))
53# define PTR_DEMANGLE(var) asm ("ror $2*" LP_SIZE "+1, %0\n" \
54 "xor %%fs:%c2, %0" \
55 : "=r" (var) \
56 : "0" (var), \
57 "i" (POINTER_GUARD))
58# endif
59#endif
60
61#endif /* POINTER_GUARD_H */
62