1  /* Changing the per-thread memory protection key, x86_64 version.
       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  #include <arch-pkey.h>
      20  #include <errno.h>
      21  
      22  int
      23  pkey_set (int key, unsigned int rights)
      24  {
      25    if (key < 0 || key > 15 || rights > 3)
      26      {
      27        __set_errno (EINVAL);
      28        return -1;
      29      }
      30    unsigned int mask = 3 << (2 * key);
      31    unsigned int pkru = pkey_read ();
      32    pkru = (pkru & ~mask) | (rights << (2 * key));
      33    pkey_write (pkru);
      34    return 0;
      35  }