1  /* Reading the per-thread memory protection key, powerpc64 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     <http://www.gnu.org/licenses/>.  */
      18  
      19  #include <arch-pkey.h>
      20  #include <errno.h>
      21  #include <sys/mman.h>
      22  
      23  int
      24  pkey_get (int key)
      25  {
      26    if (key < 0 || key > PKEY_MAX)
      27      {
      28        __set_errno (EINVAL);
      29        return -1;
      30      }
      31    unsigned int index = pkey_index (key);
      32    unsigned long int amr = pkey_read ();
      33    unsigned int bits = (amr >> index) & 3;
      34  
      35    /* Translate from AMR values.  PKEY_AMR_READ standing alone is not
      36       currently representable.  */
      37    if (bits & PKEY_AMR_READ)
      38      return PKEY_DISABLE_ACCESS;
      39    else if (bits == PKEY_AMR_WRITE)
      40      return PKEY_DISABLE_WRITE;
      41    return 0;
      42  }