1/* Assembler macros for x86.
2 Copyright (C) 2017-2021 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
26enum 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#ifdef __ASSEMBLER__
61
62/* Syntactic details of assembler. */
63
64#ifdef _CET_ENDBR
65# define _CET_NOTRACK notrack
66#else
67# define _CET_ENDBR
68# define _CET_NOTRACK
69#endif
70
71/* ELF uses byte-counts for .align, most others use log2 of count of bytes. */
72#define ALIGNARG(log2) 1<<log2
73#define ASM_SIZE_DIRECTIVE(name) .size name,.-name;
74
75/* Define an entry point visible from C. */
76#define ENTRY(name) \
77 .globl C_SYMBOL_NAME(name); \
78 .type C_SYMBOL_NAME(name),@function; \
79 .align ALIGNARG(4); \
80 C_LABEL(name) \
81 cfi_startproc; \
82 _CET_ENDBR; \
83 CALL_MCOUNT
84
85#undef END
86#define END(name) \
87 cfi_endproc; \
88 ASM_SIZE_DIRECTIVE(name)
89
90#define ENTRY_CHK(name) ENTRY (name)
91#define END_CHK(name) END (name)
92
93/* Since C identifiers are not normally prefixed with an underscore
94 on this system, the asm identifier `syscall_error' intrudes on the
95 C name space. Make sure we use an innocuous name. */
96#define syscall_error __syscall_error
97#define mcount _mcount
98
99#undef PSEUDO_END
100#define PSEUDO_END(name) \
101 END (name)
102
103/* Local label name for asm code. */
104#ifndef L
105/* ELF-like local names start with `.L'. */
106# define L(name) .L##name
107#endif
108
109#define atom_text_section .section ".text.atom", "ax"
110
111#endif /* __ASSEMBLER__ */
112
113#endif /* _X86_SYSDEP_H */
114