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linker_set.h (3903B) - Raw

      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  * Private macros, not to be used outside this header file.
     54  */
     55 
     56 /*
     57  * The userspace address sanitizer inserts redzones around global variables,
     58  * violating the assumption that linker set elements are packed.
     59  */
     60 #ifdef _KERNEL
     61 #define	__NOASAN
     62 #else
     63 #define	__NOASAN	__nosanitizeaddress
     64 #endif
     65 
     66 #define __MAKE_SET_QV(set, sym, qv)			\
     67 	__WEAK(__CONCAT(__start_set_,set));		\
     68 	__WEAK(__CONCAT(__stop_set_,set));		\
     69 	static void const * qv				\
     70 	__NOASAN					\
     71 	__set_##set##_sym_##sym __section("set_" #set)	\
     72 	__used = &(sym)
     73 #define __MAKE_SET(set, sym)	__MAKE_SET_QV(set, sym, __MAKE_SET_CONST)
     74 
     75 /*
     76  * Public macros.
     77  */
     78 #define TEXT_SET(set, sym)	__MAKE_SET(set, sym)
     79 #define DATA_SET(set, sym)	__MAKE_SET(set, sym)
     80 #define DATA_WSET(set, sym)	__MAKE_SET_QV(set, sym, )
     81 #define BSS_SET(set, sym)	__MAKE_SET(set, sym)
     82 #define ABS_SET(set, sym)	__MAKE_SET(set, sym)
     83 #define SET_ENTRY(set, sym)	__MAKE_SET(set, sym)
     84 
     85 /*
     86  * Initialize before referring to a given linker set.
     87  */
     88 #define SET_DECLARE(set, ptype)					\
     89 	extern ptype __weak_symbol *__CONCAT(__start_set_,set);	\
     90 	extern ptype __weak_symbol *__CONCAT(__stop_set_,set)
     91 
     92 #define SET_BEGIN(set)							\
     93 	(&__CONCAT(__start_set_,set))
     94 #define SET_LIMIT(set)							\
     95 	(&__CONCAT(__stop_set_,set))
     96 
     97 /*
     98  * Iterate over all the elements of a set.
     99  *
    100  * Sets always contain addresses of things, and "pvar" points to words
    101  * containing those addresses.  Thus is must be declared as "type **pvar",
    102  * and the address of each set item is obtained inside the loop by "*pvar".
    103  */
    104 #define SET_FOREACH(pvar, set)						\
    105 	for (pvar = SET_BEGIN(set); pvar < SET_LIMIT(set); pvar++)
    106 
    107 #define SET_ITEM(set, i)						\
    108 	((SET_BEGIN(set))[i])
    109 
    110 /*
    111  * Provide a count of the items in a set.
    112  */
    113 #define SET_COUNT(set)							\
    114 	(SET_LIMIT(set) - SET_BEGIN(set))
    115 
    116 #endif	/* _SYS_LINKER_SET_H_ */