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      1 /* ELF program property for Intel CET.
      2    Copyright (C) 2017-2022 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 */
     94