1  /* Changing 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_set (int key, unsigned int rights)
      25  {
      26    if (key < 0 || key > PKEY_MAX || rights > 3)
      27      {
      28        __set_errno (EINVAL);
      29        return -1;
      30      }
      31  
      32    /* Translate to AMR bit values.  */
      33    unsigned long int bits;
      34    if (rights & PKEY_DISABLE_ACCESS)
      35      /* The PKEY_DISABLE_WRITE bit does not matter.  */
      36      bits = PKEY_AMR_READ | PKEY_AMR_WRITE;
      37    else if (rights == PKEY_DISABLE_WRITE)
      38      bits = PKEY_AMR_WRITE;
      39    else
      40      bits = 0;
      41  
      42    unsigned int index = pkey_index (key);
      43    unsigned long int mask = 3UL << index;
      44    unsigned long int amr = pkey_read ();
      45    amr = (amr & ~mask) | (bits << index);
      46    pkey_write (amr);
      47    return 0;
      48  }