xref: /xnu-12377.41.6/libkern/libkern/section_keywords.h (revision bbb1b6f9e71b8cdde6e5cd6f4841f207dee3d828)
1 /*
2  * Copyright (c) 2015 Apple Inc. All rights reserved.
3  *
4  * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
5  *
6  * This file contains Original Code and/or Modifications of Original Code
7  * as defined in and that are subject to the Apple Public Source License
8  * Version 2.0 (the 'License'). You may not use this file except in
9  * compliance with the License. The rights granted to you under the License
10  * may not be used to create, or enable the creation or redistribution of,
11  * unlawful or unlicensed copies of an Apple operating system, or to
12  * circumvent, violate, or enable the circumvention or violation of, any
13  * terms of an Apple operating system software license agreement.
14  *
15  * Please obtain a copy of the License at
16  * http://www.opensource.apple.com/apsl/ and read it before using this file.
17  *
18  * The Original Code and all software distributed under the License are
19  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
20  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
21  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
22  * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
23  * Please see the License for the specific language governing rights and
24  * limitations under the License.
25  *
26  * @APPLE_OSREFERENCE_LICENSE_HEADER_END@
27  */
28 
29 #ifndef _SECTION_KEYWORDS_H
30 #define _SECTION_KEYWORDS_H
31 
32 #define __PLACE_IN_SECTION(__segment__section) \
33 	__attribute__((used, section(__segment__section)))
34 
35 #define __SEGMENT_START_SYM(seg)       asm("segment$start$" seg)
36 #define __SEGMENT_END_SYM(seg)         asm("segment$end$" seg)
37 
38 #define __SECTION_START_SYM(seg, sect) asm("section$start$" seg "$" sect)
39 #define __SECTION_END_SYM(seg, sect)   asm("section$end$" seg "$" sect)
40 
41 #if defined(__arm64__) || defined (__x86_64__)
42 
43 #define SECURITY_SEGMENT_NAME           "__DATA"
44 #define SECURITY_SECTION_NAME           "__const"
45 #define SECURITY_SEGMENT_SECTION_NAME   "__DATA,__const"
46 
47 #ifndef __BUILDING_XNU_LIBRARY__
48 #define __security_const_early const
49 #define __security_const_late __attribute__((section(SECURITY_SEGMENT_SECTION_NAME)))
50 #define __security_read_write
51 
52 #if HIBERNATION
53 #define MARK_AS_HIBERNATE_TEXT __attribute__((section("__HIB, __text, regular, pure_instructions")))
54 #define MARK_AS_HIBERNATE_DATA __attribute__((section("__HIB, __data")))
55 #define MARK_AS_HIBERNATE_DATA_CONST_LATE __attribute__((section("__HIB, __const")))
56 #endif /* HIBERNATION */
57 
58 #else /* __BUILDING_XNU_LIBRARY__ */
59 /* Special segments are not used when building for user-mode */
60 #define __security_const_early
61 #define __security_const_late
62 #define __security_read_write
63 #define MARK_AS_HIBERNATE_TEXT
64 #define MARK_AS_HIBERNATE_DATA
65 #define MARK_AS_HIBERNATE_DATA_CONST_LATE
66 #endif /* __BUILDING_XNU_LIBRARY__ */
67 
68 #endif /* __arm64__ || __x86_64__ */
69 
70 #ifndef __security_const_early
71 #define __security_const_early const
72 #endif
73 #ifndef __security_const_late
74 #define __security_const_late
75 #endif
76 #ifndef __security_read_write
77 #define __security_read_write
78 #endif
79 #ifndef MARK_AS_HIBERNATE_TEXT
80 #define MARK_AS_HIBERNATE_TEXT
81 #endif
82 #ifndef MARK_AS_HIBERNATE_DATA
83 #define MARK_AS_HIBERNATE_DATA
84 #endif
85 #ifndef MARK_AS_HIBERNATE_DATA_CONST_LATE
86 #define MARK_AS_HIBERNATE_DATA_CONST_LATE
87 #endif
88 
89 #define SECURITY_READ_ONLY_EARLY(_t) _t __security_const_early __attribute__((used))
90 #define SECURITY_READ_ONLY_LATE(_t)  _t __security_const_late  __attribute__((used))
91 #define SECURITY_READ_WRITE(_t)      _t __security_read_write  __attribute__((used))
92 
93 #if CONFIG_SPTM
94 /*
95  * Place a function in a special segment, __TEXT_BOOT_EXEC. Code placed
96  * in this segment will be allowed by the SPTM to execute during the fixups
97  * phase; the rest of the code will be mapped as RW, so that it can be overwritten.
98  * Code that is required to execute in order to apply fixups MUST be contained
99  * in this special segment.
100  */
101 #define MARK_AS_FIXUP_TEXT __attribute__((used, section("__TEXT_BOOT_EXEC,__bootcode,regular,pure_instructions")))
102 #else
103 #define MARK_AS_FIXUP_TEXT
104 #endif
105 
106 #endif /* _SECTION_KEYWORDS_H_ */
107