sysdeps/unix/sysv/linux/x86/pkey_get.c

   1 /* Reading the per-thread memory protection key, x86_64 version.
   2    Copyright (C) 2017-2022 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_get (int key)
  24 {
  25   if (key < 0 || key > 15)
  26     {
  27       __set_errno (EINVAL);
  28       return -1;
  29     }
  30   unsigned int pkru = pkey_read ();
  31   return (pkru >> (2 * key)) & 3;
  32   return 0;
  33 }