sysdeps/x86_64/feature-control.h

   1 /* x86-64 feature tuning.
   2    This file is part of the GNU C Library.
   3    Copyright (C) 2018-2024 Free Software Foundation, Inc.
   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 _X86_64_FEATURE_CONTROL_H
  20 #define _X86_64_FEATURE_CONTROL_H
  21
  22 /* For each CET feature, IBT and SHSTK, valid control values.  */
  23 enum dl_x86_cet_control
  24 {
  25   /* Enable CET features based on ELF property note.  */
  26   cet_elf_property = 0,
  27   /* Always enable CET features.  */
  28   cet_always_on,
  29   /* Always disable CET features.  */
  30   cet_always_off,
  31   /* Enable CET features permissively.  */
  32   cet_permissive
  33 };
  34
  35 /* PLT rewrite control.  */
  36 enum dl_plt_rewrite_control
  37 {
  38   /* No PLT rewrite.  */
  39   plt_rewrite_none,
  40   /* Rewrite PLT with JMP at run-time.  */
  41   plt_rewrite_jmp,
  42   /* Rewrite PLT with JMP and JMPABS at run-time.  */
  43   plt_rewrite_jmpabs
  44 };
  45
  46 struct dl_x86_feature_control
  47 {
  48   enum dl_x86_cet_control ibt : 2;
  49   enum dl_x86_cet_control shstk : 2;
  50   enum dl_plt_rewrite_control plt_rewrite : 2;
  51 };
  52
  53 #endif /* feature-control.h */