1 /* Helper functions for manipulating memory protection keys, for powerpc64.
2 Copyright (C) 2017-2022 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 <http://www.gnu.org/licenses/>. */
18
19 #ifndef _ARCH_PKEY_H
20 #define _ARCH_PKEY_H
21
22 /* Read and write access bits in the AMR register. Needs to be
23 translated from and to PKEY_DISABLE_* flags. */
24 #define PKEY_AMR_READ 1UL
25 #define PKEY_AMR_WRITE 2UL
26
27 /* Return the value of the AMR register. */
28 static inline unsigned long int
pkey_read(void)29 pkey_read (void)
30 {
31 unsigned long int result;
32 __asm__ volatile ("mfspr %0, 13" : "=r" (result));
33 return result;
34 }
35
36 /* Overwrite the AMR register with VALUE. */
37 static inline void
pkey_write(unsigned long int value)38 pkey_write (unsigned long int value)
39 {
40 __asm__ volatile ("isync; mtspr 13, %0; isync" : : "r" (value));
41 }
42
43 /* Number of the largest supported key. This depends on the width of
44 the AMR register. */
45 #define PKEY_MAX (sizeof (unsigned long int) * 8 / 2 - 1)
46 _Static_assert (PKEY_MAX == 15 || PKEY_MAX == 31, "PKEY_MAX value");
47
48 /* Translate key number into AMR index position. */
49 static inline int
pkey_index(int key)50 pkey_index (int key)
51 {
52 return 2 * (PKEY_MAX - key);
53 }
54
55 #endif /* _ARCH_PKEY_H */
56