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 | #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 | |