gcc/config/i386/cet.h

   1 /* ELF program property for Intel CET.
   2    Copyright (C) 2017-2018 Free Software Foundation, Inc.
   3
   4    This file is free software; you can redistribute it and/or modify it
   5    under the terms of the GNU General Public License as published by the
   6    Free Software Foundation; either version 3, or (at your option) any
   7    later version.
   8
   9    This file is distributed in the hope that it will be useful, but
  10    WITHOUT ANY WARRANTY; without even the implied warranty of
  11    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12    General Public License for more details.
  13
  14    Under Section 7 of GPL version 3, you are granted additional
  15    permissions described in the GCC Runtime Library Exception, version
  16    3.1, as published by the Free Software Foundation.
  17
  18    You should have received a copy of the GNU General Public License and
  19    a copy of the GCC Runtime Library Exception along with this program;
  20    see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
  21    <http://www.gnu.org/licenses/>.
  22  */
  23
  24 /* Add x86 feature with IBT and/or SHSTK bits to ELF program property
  25    if they are enabled.  Otherwise, contents in this header file are
  26    unused.  Define _CET_ENDBR for assembly codes.  _CET_ENDBR should be
  27    placed unconditionally at the entrance of a function whose address
  28    may be taken.  */
  29
  30 #ifndef _CET_H_INCLUDED
  31 #define _CET_H_INCLUDED
  32
  33 #ifdef __ASSEMBLER__
  34
  35 # if defined __CET__ && (__CET__ & 1) != 0
  36 #  ifdef __x86_64__
  37 #   define _CET_ENDBR endbr64
  38 #  else
  39 #   define _CET_ENDBR endbr32
  40 #  endif
  41 # else
  42 #  define _CET_ENDBR
  43 # endif
  44
  45 # ifdef __ELF__
  46 #  ifdef __CET__
  47 #   if (__CET__ & 1) != 0
  48 /* GNU_PROPERTY_X86_FEATURE_1_IBT.  */
  49 #    define __PROPERTY_IBT 0x1
  50 #   else
  51 #    define __PROPERTY_IBT 0x0
  52 #   endif
  53
  54 #   if (__CET__ & 2) != 0
  55 /* GNU_PROPERTY_X86_FEATURE_1_SHSTK.  */
  56 #    define __PROPERTY_SHSTK 0x2
  57 #   else
  58 #    define __PROPERTY_SHSTK 0x0
  59 #   endif
  60
  61 #   define __PROPERTY_BITS (__PROPERTY_IBT | __PROPERTY_SHSTK)
  62
  63 #   ifdef __LP64__
  64 #    define __PROPERTY_ALIGN 3
  65 #   else
  66 #    define __PROPERTY_ALIGN 2
  67 #   endif
  68
  69         .pushsection ".note.gnu.property", "a"
  70         .p2align __PROPERTY_ALIGN
  71         .long 1f - 0f           /* name length.  */
  72         .long 4f - 1f           /* data length.  */
  73         /* NT_GNU_PROPERTY_TYPE_0.   */
  74         .long 5                 /* note type.  */
  75 0:
  76         .asciz "GNU"            /* vendor name.  */
  77 1:
  78         .p2align __PROPERTY_ALIGN
  79         /* GNU_PROPERTY_X86_FEATURE_1_AND.  */
  80         .long 0xc0000002        /* pr_type.  */
  81         .long 3f - 2f           /* pr_datasz.  */
  82 2:
  83         /* GNU_PROPERTY_X86_FEATURE_1_XXX.  */
  84         .long __PROPERTY_BITS
  85 3:
  86         .p2align __PROPERTY_ALIGN
  87 4:
  88         .popsection
  89 #  endif /* __CET__ */
  90 # endif /* __ELF__ */
  91 #endif /* __ASSEMBLER__ */
  92
  93 #endif /* _CET_H_INCLUDED */