1  /* Helper functions for manipulating memory protection keys.
       2     Copyright (C) 2017-2023 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 _ARCH_PKEY_H
      20  #define _ARCH_PKEY_H
      21  
      22  /* Return the value of the PKRU register.  */
      23  static inline unsigned int
      24  pkey_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.  */
      33  static inline void
      34  pkey_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 */