sysdeps/unix/sysv/linux/powerpc/powerpc64/arch-pkey.h

   1 /* Helper functions for manipulating memory protection keys, for powerpc64.
   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    <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
  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
  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
  50 pkey_index (int key)
  51 {
  52   return 2 * (PKEY_MAX - key);
  53 }
  54
  55 #endif /* _ARCH_PKEY_H */