. file- and functionality-compatible with previous situation
          (FreeBSD csu) (with a crt1.o -> crt0.o symlink in /usr/lib)
        . harmonizes source with netbsd
        . harmonizes linker invocation (e.g. clang) with netbsd
        . helpful to get some arm code in there for the arm port project
		
	
			
		
			
				
	
	
		
			209 lines
		
	
	
		
			6.8 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
			
		
		
	
	
			209 lines
		
	
	
		
			6.8 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
/*	$NetBSD: cdefs_elf.h,v 1.34 2010/12/08 01:18:55 joerg Exp $	*/
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/*
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 * Copyright (c) 1995, 1996 Carnegie-Mellon University.
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 * All rights reserved.
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 *
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 * Author: Chris G. Demetriou
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 *
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 * Permission to use, copy, modify and distribute this software and
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 * its documentation is hereby granted, provided that both the copyright
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 * notice and this permission notice appear in all copies of the
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 * software, derivative works or modified versions, and any portions
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 * thereof, and that both notices appear in supporting documentation.
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 *
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 * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
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 * CONDITION.  CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND
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 * FOR ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
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 *
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 * Carnegie Mellon requests users of this software to return to
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 *
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 *  Software Distribution Coordinator  or  Software.Distribution@CS.CMU.EDU
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 *  School of Computer Science
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 *  Carnegie Mellon University
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 *  Pittsburgh PA 15213-3890
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 *
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 * any improvements or extensions that they make and grant Carnegie the
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 * rights to redistribute these changes.
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 */
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#ifndef _SYS_CDEFS_ELF_H_
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#define	_SYS_CDEFS_ELF_H_
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#ifdef __LEADING_UNDERSCORE
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#define	_C_LABEL(x)	__CONCAT(_,x)
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#define _C_LABEL_STRING(x)	"_"x
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#else
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#define	_C_LABEL(x)	x
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#define _C_LABEL_STRING(x)	x
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#endif
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#if __STDC__
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#define	___RENAME(x)	__asm(___STRING(_C_LABEL(x)))
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#else
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#ifdef __LEADING_UNDERSCORE
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#define	___RENAME(x)	____RENAME(_/**/x)
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#define	____RENAME(x)	__asm(___STRING(x))
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#else
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#define	___RENAME(x)	__asm(___STRING(x))
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#endif
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#endif
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#define	__indr_reference(sym,alias)	/* nada, since we do weak refs */
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#if __STDC__
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#define	__strong_alias(alias,sym)	       				\
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    __asm(".global " _C_LABEL_STRING(#alias) "\n"			\
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	    _C_LABEL_STRING(#alias) " = " _C_LABEL_STRING(#sym));
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#define	__weak_alias(alias,sym)						\
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    __asm(".weak " _C_LABEL_STRING(#alias) "\n"			\
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	    _C_LABEL_STRING(#alias) " = " _C_LABEL_STRING(#sym));
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/* Do not use __weak_extern, use __weak_reference instead */
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#define	__weak_extern(sym)						\
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    __asm(".weak " _C_LABEL_STRING(#sym));
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#if __GNUC_PREREQ__(4, 0)
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#define	__weak_reference(sym)	__attribute__((__weakref__))
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#else
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#define	__weak_reference(sym)	; __asm(".weak " _C_LABEL_STRING(#sym))
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#endif
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#if defined(__clang__)
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#define	__warn_references(sym,msg)					\
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    static __attribute__((__used__, __section__(".gnu.warning." #sym))) \
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    const char ___CONCAT(__warn_reference_##sym,__COUNTER__)[] = msg;
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#else
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#define	__warn_references(sym,msg)					\
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    __asm(".pushsection .gnu.warning." #sym "\n"			\
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	  ".ascii \"" msg "\"\n"					\
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	  ".popsection");
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#endif
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#else /* !__STDC__ */
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#ifdef __LEADING_UNDERSCORE
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#define __weak_alias(alias,sym) ___weak_alias(_/**/alias,_/**/sym)
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#define	___weak_alias(alias,sym)					\
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    __asm(".weak alias\nalias = sym");
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#else
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#define	__weak_alias(alias,sym)						\
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    __asm(".weak alias\nalias = sym");
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#endif
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#ifdef __LEADING_UNDERSCORE
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#define __weak_extern(sym) ___weak_extern(_/**/sym)
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#define	___weak_extern(sym)						\
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    __asm(".weak sym");
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#else
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#define	__weak_extern(sym)						\
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    __asm(".weak sym");
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#endif
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#define	__warn_references(sym,msg)					\
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    __asm(".pushsection .gnu.warning.sym\n"				\
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	  ".ascii \"" msg "\"\n"					\
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	  ".popsection");
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#endif /* !__STDC__ */
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#if defined(__clang__)
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#define	__SECTIONSTRING(_sec, _str)					\
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	static __attribute__((__used__, __section__(#_sec))) const char \
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	___CONCAT(__sectstr,__COUNTER__)[] = _str
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#elif __STDC__
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#define	__SECTIONSTRING(_sec, _str)					\
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	__asm(".pushsection " #_sec "\n"				\
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	      ".asciz \"" _str "\"\n"					\
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	      ".popsection")
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#else
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#define	__SECTIONSTRING(_sec, _str)					\
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	__asm(".pushsection _sec\n"					\
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	      ".asciz \"" _str "\"\n"					\
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	      ".popsection")
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#endif
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#define	__IDSTRING(_n,_s)		__SECTIONSTRING(.ident,_s)
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#define	__RCSID(_s)			__IDSTRING(rcsid,_s)
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#define	__SCCSID(_s)
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#define __SCCSID2(_s)
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#define	__COPYRIGHT(_s)			__SECTIONSTRING(.copyright,_s)
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#define	__KERNEL_RCSID(_n, _s)		__RCSID(_s)
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#define	__KERNEL_SCCSID(_n, _s)
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#define	__KERNEL_COPYRIGHT(_n, _s)	__COPYRIGHT(_s)
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#ifndef __lint__
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#define	__link_set_make_entry(set, sym)					\
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	static void const * const __link_set_##set##_sym_##sym		\
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	    __section("link_set_" #set) __used = &sym
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#define	__link_set_make_entry2(set, sym, n)				\
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	static void const * const __link_set_##set##_sym_##sym##_##n	\
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	    __section("link_set_" #set) __used = &sym[n]
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#else
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#define	__link_set_make_entry(set, sym)					\
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	extern void const * const __link_set_##set##_sym_##sym
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#define	__link_set_make_entry2(set, sym, n)				\
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	extern void const * const __link_set_##set##_sym_##sym##_##n
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#endif /* __lint__ */
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#define	__link_set_add_text(set, sym)	__link_set_make_entry(set, sym)
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#define	__link_set_add_rodata(set, sym)	__link_set_make_entry(set, sym)
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#define	__link_set_add_data(set, sym)	__link_set_make_entry(set, sym)
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#define	__link_set_add_bss(set, sym)	__link_set_make_entry(set, sym)
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#define	__link_set_add_text2(set, sym, n)   __link_set_make_entry2(set, sym, n)
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#define	__link_set_add_rodata2(set, sym, n) __link_set_make_entry2(set, sym, n)
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#define	__link_set_add_data2(set, sym, n)   __link_set_make_entry2(set, sym, n)
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#define	__link_set_add_bss2(set, sym, n)    __link_set_make_entry2(set, sym, n)
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#define	__link_set_decl(set, ptype)					\
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	extern ptype * const __start_link_set_##set[];			\
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	extern ptype * const __stop_link_set_##set[]			\
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#define	__link_set_start(set)	(__start_link_set_##set)
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#define	__link_set_end(set)	(__stop_link_set_##set)
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#define	__link_set_count(set)						\
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	(__link_set_end(set) - __link_set_start(set))
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#ifdef _KERNEL
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/*
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 * On multiprocessor systems we can gain an improvement in performance
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 * by being mindful of which cachelines data is placed in.
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 *
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 * __read_mostly:
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 *
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 *	It makes sense to ensure that rarely modified data is not
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 *	placed in the same cacheline as frequently modified data.
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 *	To mitigate the phenomenon known as "false-sharing" we
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 *	can annotate rarely modified variables with __read_mostly.
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 *	All such variables are placed into the .data.read_mostly
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 *	section in the kernel ELF.
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 *
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 *	Prime candidates for __read_mostly annotation are variables
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 *	which are hardly ever modified and which are used in code
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 *	hot-paths, e.g. pmap_initialized.
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 *
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 * __cacheline_aligned:
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 *
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 *	Some data structures (mainly locks) benefit from being aligned
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 *	on a cacheline boundary, and having a cacheline to themselves.
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 *	This way, the modification of other data items cannot adversely
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 *	affect the lock and vice versa.
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 *
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 *	Any variables annotated with __cacheline_aligned will be
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 *	placed into the .data.cacheline_aligned ELF section.
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 */
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#define	__read_mostly						\
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    __attribute__((__section__(".data.read_mostly")))
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#define	__cacheline_aligned					\
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    __attribute__((__aligned__(COHERENCY_UNIT)			\
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		 __section__(".data.cacheline_aligned")))
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#endif /* _KERNEL */
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#endif /* !_SYS_CDEFS_ELF_H_ */
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