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
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#ifdef __ASSEMBLER__
52
53/* Syntactic details of assembler. */
54
55#ifdef _CET_ENDBR
56# define _CET_NOTRACK notrack
57#else
58# define _CET_ENDBR
59# define _CET_NOTRACK
60#endif
61
62/* ELF uses byte-counts for .align, most others use log2 of count of bytes. */
63#define ALIGNARG(log2) 1<<log2
64#define ASM_SIZE_DIRECTIVE(name) .size name,.-name;
65
66/* Define an entry point visible from C. */
67#define ENTRY(name) \
68 .globl C_SYMBOL_NAME(name); \
69 .type C_SYMBOL_NAME(name),@function; \
70 .align ALIGNARG(4); \
71 C_LABEL(name) \
72 cfi_startproc; \
73 _CET_ENDBR; \
74 CALL_MCOUNT
75
76#undef END
77#define END(name) \
78 cfi_endproc; \
79 ASM_SIZE_DIRECTIVE(name)
80
81#define ENTRY_CHK(name) ENTRY (name)
82#define END_CHK(name) END (name)
83
84/* Since C identifiers are not normally prefixed with an underscore
85 on this system, the asm identifier `syscall_error' intrudes on the
86 C name space. Make sure we use an innocuous name. */
87#define syscall_error __syscall_error
88#define mcount _mcount
89
90#undef PSEUDO_END
91#define PSEUDO_END(name) \
92 END (name)
93
94/* Local label name for asm code. */
95#ifndef L
96/* ELF-like local names start with `.L'. */
97# define L(name) .L##name
98#endif
99
100#define atom_text_section .section ".text.atom", "ax"
101
102#endif /* __ASSEMBLER__ */
103
104#endif /* _X86_SYSDEP_H */
105