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 */ 123