1/* Helper functions for manipulating memory protection keys.
2 Copyright (C) 2017-2021 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 _ARCH_PKEY_H
20#define _ARCH_PKEY_H
21
22/* Return the value of the PKRU register. */
23static inline unsigned int
24pkey_read (void)
25{
26 unsigned int result;
27 __asm__ volatile (".byte 0x0f, 0x01, 0xee"
28 : "=a" (result) : "c" (0) : "rdx");
29 return result;
30}
31
32/* Overwrite the PKRU register with VALUE. */
33static inline void
34pkey_write (unsigned int value)
35{
36 __asm__ volatile (".byte 0x0f, 0x01, 0xef"
37 : : "a" (value), "c" (0), "d" (0));
38}
39
40#endif /* _ARCH_PKEY_H */
41