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1 /*-
2  * SPDX-License-Identifier: BSD-2-Clause
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 
30 #ifndef _SYS_LINKER_SET_H_
31 #define _SYS_LINKER_SET_H_
32 
33 /*
34  * The following macros are used to declare global sets of objects, which
35  * are collected by the linker into a `linker_set' as defined below.
36  * For ELF, this is done by constructing a separate segment for each set.
37  */
38 
39 #if defined(__powerpc64__) && (!defined(_CALL_ELF) || _CALL_ELF == 1)
40 /*
41  * ELFv1 pointers to functions are actaully pointers to function
42  * descriptors.
43  *
44  * Move the symbol pointer from ".text" to ".data" segment, to make
45  * the GCC compiler happy:
46  */
47 #define	__MAKE_SET_CONST
48 #else
49 #define	__MAKE_SET_CONST const
50 #endif
51 
52 /*
53  * Function or variable should not be sanitized, i.e. by AddressSanitizer.
54  * GCC has the nosanitize attribute, but as a function attribute only, and
55  * warns on use as a variable attribute.
56  */
57 #if __has_attribute(no_sanitize) && defined(__clang__)
58 #define __nosanitizeaddress     __attribute__((no_sanitize("address")))
59 #else
60 #define __nosanitizeaddress
61 #endif
62 
63 /*
64  * Private macros, not to be used outside this header file.
65  */
66 #ifdef __GNUCLIKE___SECTION
67 #define __MAKE_SET_QV(set, sym, qv)			\
68 	__GLOBL(__CONCAT(__start_set_,set));		\
69 	__GLOBL(__CONCAT(__stop_set_,set));		\
70 	static void const * qv				\
71 	__set_##set##_sym_##sym __section(".set_" #set)	\
72 	__nosanitizeaddress				\
73 	__used = &(sym)
74 #define __MAKE_SET(set, sym)	__MAKE_SET_QV(set, sym, __MAKE_SET_CONST)
75 #else /* !__GNUCLIKE___SECTION */
76 #error this file needs to be ported to your compiler
77 #endif /* __GNUCLIKE___SECTION */
78 
79 /*
80  * Public macros.
81  */
82 #define TEXT_SET(set, sym)	__MAKE_SET(set, sym)
83 #define DATA_SET(set, sym)	__MAKE_SET(set, sym)
84 #define DATA_WSET(set, sym)	__MAKE_SET_QV(set, sym, )
85 #define BSS_SET(set, sym)	__MAKE_SET(set, sym)
86 #define ABS_SET(set, sym)	__MAKE_SET(set, sym)
87 #define SET_ENTRY(set, sym)	__MAKE_SET(set, sym)
88 
89 /*
90  * Initialize before referring to a given linker set.
91  */
92 #define SET_DECLARE(set, ptype)					\
93 	extern ptype __attribute__((__weak__)) *__CONCAT(__start_set_,set);	\
94 	extern ptype __attribute__((__weak__)) *__CONCAT(__stop_set_,set)
95 
96 #define SET_BEGIN(set)							\
97 	(&__CONCAT(__start_set_,set))
98 #define SET_LIMIT(set)							\
99 	(&__CONCAT(__stop_set_,set))
100 
101 /*
102  * Iterate over all the elements of a set.
103  *
104  * Sets always contain addresses of things, and "pvar" points to words
105  * containing those addresses.  Thus is must be declared as "type **pvar",
106  * and the address of each set item is obtained inside the loop by "*pvar".
107  */
108 #define SET_FOREACH(pvar, set)						\
109 	for (pvar = SET_BEGIN(set); pvar < SET_LIMIT(set); pvar++)
110 
111 #define SET_ITEM(set, i)						\
112 	((SET_BEGIN(set))[i])
113 
114 /*
115  * Provide a count of the items in a set.
116  */
117 #define SET_COUNT(set)							\
118 	(SET_LIMIT(set) - SET_BEGIN(set))
119 
120 #endif	/* _SYS_LINKER_SET_H_ */
121