sysdeps/x86/sysdep.h

   1 /* Assembler macros for x86.
   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 #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 /* Offset for fxsave/xsave area used by _dl_runtime_resolve.  Also need
  52    space to preserve RCX, RDX, RSI, RDI, R8, R9 and RAX.  It must be
  53    aligned to 16 bytes for fxsave and 64 bytes for xsave.  */
  54 #define STATE_SAVE_OFFSET (8 * 7 + 8)
  55
  56 /* Save SSE, AVX, AVX512, mask and bound registers.  */
  57 #define STATE_SAVE_MASK \
  58   ((1 << 1) | (1 << 2) | (1 << 3) | (1 << 5) | (1 << 6) | (1 << 7))
  59
  60 /* Constants for bits in __x86_string_control:  */
  61
  62 /* Avoid short distance REP MOVSB.  */
  63 #define X86_STRING_CONTROL_AVOID_SHORT_DISTANCE_REP_MOVSB       (1 << 0)
  64
  65 #ifdef  __ASSEMBLER__
  66
  67 /* Syntactic details of assembler.  */
  68
  69 #ifdef _CET_ENDBR
  70 # define _CET_NOTRACK notrack
  71 #else
  72 # define _CET_ENDBR
  73 # define _CET_NOTRACK
  74 #endif
  75
  76 /* ELF uses byte-counts for .align, most others use log2 of count of bytes.  */
  77 #define ALIGNARG(log2) 1<<log2
  78 #define ASM_SIZE_DIRECTIVE(name) .size name,.-name;
  79
  80 /* Define an entry point visible from C.  */
  81 #define ENTRY_P2ALIGN(name, alignment)                                        \
  82   .globl C_SYMBOL_NAME(name);                                                 \
  83   .type C_SYMBOL_NAME(name),@function;                                        \
  84   .align ALIGNARG(alignment);                                                 \
  85   C_LABEL(name)                                                               \
  86   cfi_startproc;                                                              \
  87   _CET_ENDBR;                                                                 \
  88   CALL_MCOUNT
  89
  90 /* Common entry 16 byte aligns.  */
  91 #define ENTRY(name) ENTRY_P2ALIGN (name, 4)
  92
  93 #undef  END
  94 #define END(name)                                                             \
  95   cfi_endproc;                                                                \
  96   ASM_SIZE_DIRECTIVE(name)
  97
  98 #define ENTRY_CHK(name) ENTRY (name)
  99 #define END_CHK(name) END (name)
 100
 101 /* Since C identifiers are not normally prefixed with an underscore
 102    on this system, the asm identifier `syscall_error' intrudes on the
 103    C name space.  Make sure we use an innocuous name.  */
 104 #define syscall_error   __syscall_error
 105 #define mcount          _mcount
 106
 107 #undef  PSEUDO_END
 108 #define PSEUDO_END(name)                                                      \
 109   END (name)
 110
 111 /* Local label name for asm code. */
 112 #ifndef L
 113 /* ELF-like local names start with `.L'.  */
 114 # define LOCAL_LABEL(name) .L##name
 115 # define L(name)        LOCAL_LABEL(name)
 116 #endif
 117
 118 #define atom_text_section .section ".text.atom", "ax"
 119
 120 #endif  /* __ASSEMBLER__ */
 121
 122 #endif  /* _X86_SYSDEP_H */