FreeBSD/Linux Kernel Cross Reference
sys/sys/linker_set.h
1 /*-
2 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
3 *
4 * Copyright (c) 1999 John D. Polstra
5 * Copyright (c) 1999,2001 Peter Wemm <peter@FreeBSD.org>
6 * All rights reserved.
7 *
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
10 * are met:
11 * 1. Redistributions of source code must retain the above copyright
12 * notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 * notice, this list of conditions and the following disclaimer in the
15 * documentation and/or other materials provided with the distribution.
16 *
17 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27 * SUCH DAMAGE.
28 *
29 * $FreeBSD$
30 */
31
32 #ifndef _SYS_LINKER_SET_H_
33 #define _SYS_LINKER_SET_H_
34
35 /*
36 * The following macros are used to declare global sets of objects, which
37 * are collected by the linker into a `linker_set' as defined below.
38 * For ELF, this is done by constructing a separate segment for each set.
39 */
40
41 #if defined(__powerpc64__) && (!defined(_CALL_ELF) || _CALL_ELF == 1)
42 /*
43 * ELFv1 pointers to functions are actaully pointers to function
44 * descriptors.
45 *
46 * Move the symbol pointer from ".text" to ".data" segment, to make
47 * the GCC compiler happy:
48 */
49 #define __MAKE_SET_CONST
50 #else
51 #define __MAKE_SET_CONST const
52 #endif
53
54 /*
55 * Private macros, not to be used outside this header file.
56 */
57
58 /*
59 * The userspace address sanitizer inserts redzones around global variables,
60 * violating the assumption that linker set elements are packed.
61 */
62 #ifdef _KERNEL
63 #define __NOASAN
64 #else
65 #define __NOASAN __nosanitizeaddress
66 #endif
67
68 #define __MAKE_SET_QV(set, sym, qv) \
69 __WEAK(__CONCAT(__start_set_,set)); \
70 __WEAK(__CONCAT(__stop_set_,set)); \
71 static void const * qv \
72 __NOASAN \
73 __set_##set##_sym_##sym __section("set_" #set) \
74 __used = &(sym)
75 #define __MAKE_SET(set, sym) __MAKE_SET_QV(set, sym, __MAKE_SET_CONST)
76
77 /*
78 * Public macros.
79 */
80 #define TEXT_SET(set, sym) __MAKE_SET(set, sym)
81 #define DATA_SET(set, sym) __MAKE_SET(set, sym)
82 #define DATA_WSET(set, sym) __MAKE_SET_QV(set, sym, )
83 #define BSS_SET(set, sym) __MAKE_SET(set, sym)
84 #define ABS_SET(set, sym) __MAKE_SET(set, sym)
85 #define SET_ENTRY(set, sym) __MAKE_SET(set, sym)
86
87 /*
88 * Initialize before referring to a given linker set.
89 */
90 #define SET_DECLARE(set, ptype) \
91 extern ptype __weak_symbol *__CONCAT(__start_set_,set); \
92 extern ptype __weak_symbol *__CONCAT(__stop_set_,set)
93
94 #define SET_BEGIN(set) \
95 (&__CONCAT(__start_set_,set))
96 #define SET_LIMIT(set) \
97 (&__CONCAT(__stop_set_,set))
98
99 /*
100 * Iterate over all the elements of a set.
101 *
102 * Sets always contain addresses of things, and "pvar" points to words
103 * containing those addresses. Thus is must be declared as "type **pvar",
104 * and the address of each set item is obtained inside the loop by "*pvar".
105 */
106 #define SET_FOREACH(pvar, set) \
107 for (pvar = SET_BEGIN(set); pvar < SET_LIMIT(set); pvar++)
108
109 #define SET_ITEM(set, i) \
110 ((SET_BEGIN(set))[i])
111
112 /*
113 * Provide a count of the items in a set.
114 */
115 #define SET_COUNT(set) \
116 (SET_LIMIT(set) - SET_BEGIN(set))
117
118 #endif /* _SYS_LINKER_SET_H_ */
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