sysdeps/x86/sysdep.h

   1 /* Assembler macros for x86.
   2    Copyright (C) 2017-2018 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 #ifndef _X86_SYSDEP_H
  20 #define _X86_SYSDEP_H 1
  21
  22 #include <sysdeps/generic/sysdep.h>
  23
  24 /* __CET__ is defined by GCC with Control-Flow Protection values:
  25
  26 enum cf_protection_level
  27 {
  28   CF_NONE = 0,
  29   CF_BRANCH = 1 << 0,
  30   CF_RETURN = 1 << 1,
  31   CF_FULL = CF_BRANCH | CF_RETURN,
  32   CF_SET = 1 << 2
  33 };
  34 */
  35
  36 /* Set if CF_BRANCH (IBT) is enabled.  */
  37 #define X86_FEATURE_1_IBT       (1U << 0)
  38 /* Set if CF_RETURN (SHSTK) is enabled.  */
  39 #define X86_FEATURE_1_SHSTK     (1U << 1)
  40
  41 #ifdef __CET__
  42 # define CET_ENABLED    1
  43 # define IBT_ENABLED    (__CET__ & X86_FEATURE_1_IBT)
  44 # define SHSTK_ENABLED  (__CET__ & X86_FEATURE_1_SHSTK)
  45 #else
  46 # define CET_ENABLED    0
  47 # define IBT_ENABLED    0
  48 # define SHSTK_ENABLED  0
  49 #endif
  50
  51 #ifdef  __ASSEMBLER__
  52
  53 /* Syntactic details of assembler.  */
  54
  55 /* ELF uses byte-counts for .align, most others use log2 of count of bytes.  */
  56 #define ALIGNARG(log2) 1<<log2
  57 #define ASM_SIZE_DIRECTIVE(name) .size name,.-name;
  58
  59 /* Define an entry point visible from C.  */
  60 #define ENTRY(name)                                                           \
  61   .globl C_SYMBOL_NAME(name);                                                 \
  62   .type C_SYMBOL_NAME(name),@function;                                        \
  63   .align ALIGNARG(4);                                                         \
  64   C_LABEL(name)                                                               \
  65   cfi_startproc;                                                              \
  66   CALL_MCOUNT
  67
  68 #undef  END
  69 #define END(name)                                                             \
  70   cfi_endproc;                                                                \
  71   ASM_SIZE_DIRECTIVE(name)
  72
  73 #define ENTRY_CHK(name) ENTRY (name)
  74 #define END_CHK(name) END (name)
  75
  76 /* Since C identifiers are not normally prefixed with an underscore
  77    on this system, the asm identifier `syscall_error' intrudes on the
  78    C name space.  Make sure we use an innocuous name.  */
  79 #define syscall_error   __syscall_error
  80 #define mcount          _mcount
  81
  82 #undef  PSEUDO_END
  83 #define PSEUDO_END(name)                                                      \
  84   END (name)
  85
  86 /* Local label name for asm code. */
  87 #ifndef L
  88 /* ELF-like local names start with `.L'.  */
  89 # define L(name)        .L##name
  90 #endif
  91
  92 #define atom_text_section .section ".text.atom", "ax"
  93
  94 #endif  /* __ASSEMBLER__ */
  95
  96 #endif  /* _X86_SYSDEP_H */