/* $NetBSD: cdefs_elf.h,v 1.58 2021/06/04 01:58:02 thorpej Exp $ */ /* * Copyright (c) 1995, 1996 Carnegie-Mellon University. * All rights reserved. * * Author: Chris G. Demetriou * * Permission to use, copy, modify and distribute this software and * its documentation is hereby granted, provided that both the copyright * notice and this permission notice appear in all copies of the * software, derivative works or modified versions, and any portions * thereof, and that both notices appear in supporting documentation. * * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS" * CONDITION. CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND * FOR ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE. * * Carnegie Mellon requests users of this software to return to * * Software Distribution Coordinator or Software.Distribution@CS.CMU.EDU * School of Computer Science * Carnegie Mellon University * Pittsburgh PA 15213-3890 * * any improvements or extensions that they make and grant Carnegie the * rights to redistribute these changes. */ #ifndef _SYS_CDEFS_ELF_H_ #define _SYS_CDEFS_ELF_H_ #ifdef __LEADING_UNDERSCORE #define _C_LABEL(x) __CONCAT(_,x) #define _C_LABEL_STRING(x) "_"x #else #define _C_LABEL(x) x #define _C_LABEL_STRING(x) x #endif #if __STDC__ #define ___RENAME(x) __asm(___STRING(_C_LABEL(x))) #else #ifdef __LEADING_UNDERSCORE #define ___RENAME(x) ____RENAME(_/**/x) #define ____RENAME(x) __asm(___STRING(x)) #else #define ___RENAME(x) __asm(___STRING(x)) #endif #endif #define __indr_reference(sym,alias) /* nada, since we do weak refs */ #if __STDC__ #define __strong_alias(alias,sym) \ __asm(".global " _C_LABEL_STRING(#alias) "\n" \ _C_LABEL_STRING(#alias) " = " _C_LABEL_STRING(#sym)); #define __weak_alias(alias,sym) \ __asm(".weak " _C_LABEL_STRING(#alias) "\n" \ _C_LABEL_STRING(#alias) " = " _C_LABEL_STRING(#sym)); /* Do not use __weak_extern, use __weak_reference instead */ #define __weak_extern(sym) \ __asm(".weak " _C_LABEL_STRING(#sym)); #if __GNUC_PREREQ__(4, 0) #define __weak __attribute__((__weak__)) #else #define __weak #endif #if __GNUC_PREREQ__(4, 0) #define __weak_reference(sym) __attribute__((__weakref__(#sym))) #else #define __weak_reference(sym) ; __asm(".weak " _C_LABEL_STRING(#sym)) #endif #if __GNUC_PREREQ__(4, 2) #define __weakref_visible static #else #define __weakref_visible extern #endif #define __warn_references(sym,msg) \ __asm(".pushsection .gnu.warning." #sym "\n" \ ".ascii \"" msg "\"\n" \ ".popsection"); #else /* !__STDC__ */ #ifdef __LEADING_UNDERSCORE #define __weak_alias(alias,sym) ___weak_alias(_/**/alias,_/**/sym) #define ___weak_alias(alias,sym) \ __asm(".weak alias\nalias = sym"); #else #define __weak_alias(alias,sym) \ __asm(".weak alias\nalias = sym"); #endif #ifdef __LEADING_UNDERSCORE #define __weak_extern(sym) ___weak_extern(_/**/sym) #define ___weak_extern(sym) \ __asm(".weak sym"); #else #define __weak_extern(sym) \ __asm(".weak sym"); #endif #define __warn_references(sym,msg) \ __asm(".pushsection .gnu.warning.sym\n" \ ".ascii \"" msg "\"\n" \ ".popsection"); #endif /* !__STDC__ */ #if __arm__ #define __ifunc(name, resolver) \ __asm(".globl " _C_LABEL_STRING(#name) "\n" \ ".type " _C_LABEL_STRING(#name) ", %gnu_indirect_function\n" \ _C_LABEL_STRING(#name) " = " _C_LABEL_STRING(#resolver)) #define __hidden_ifunc(name, resolver) \ __asm(".globl " _C_LABEL_STRING(#name) "\n" \ ".hidden " _C_LABEL_STRING(#name) "\n" \ ".type " _C_LABEL_STRING(#name) ", %gnu_indirect_function\n" \ _C_LABEL_STRING(#name) " = " _C_LABEL_STRING(#resolver)) #else #define __ifunc(name, resolver) \ __asm(".globl " _C_LABEL_STRING(#name) "\n" \ ".type " _C_LABEL_STRING(#name) ", @gnu_indirect_function\n" \ _C_LABEL_STRING(#name) " = " _C_LABEL_STRING(#resolver)) #define __hidden_ifunc(name, resolver) \ __asm(".globl " _C_LABEL_STRING(#name) "\n" \ ".hidden " _C_LABEL_STRING(#name) "\n" \ ".type " _C_LABEL_STRING(#name) ", @gnu_indirect_function\n" \ _C_LABEL_STRING(#name) " = " _C_LABEL_STRING(#resolver)) #endif #ifdef __arm__ #if __STDC__ # define __SECTIONSTRING(_sec, _str) \ __asm(".pushsection " #_sec ",\"MS\",%progbits,1\n" \ ".asciz \"" _str "\"\n" \ ".popsection") #else # define __SECTIONSTRING(_sec, _str) \ __asm(".pushsection " _sec ",\"MS\",%progbits,1\n" \ ".asciz \"" _str "\"\n" \ ".popsection") # endif #else # if __STDC__ # define __SECTIONSTRING(_sec, _str) \ __asm(".pushsection " #_sec ",\"MS\",@progbits,1\n" \ ".asciz \"" _str "\"\n" \ ".popsection") # else # define __SECTIONSTRING(_sec, _str) \ __asm(".pushsection " _sec ",\"MS\",@progbits,1\n" \ ".asciz \"" _str "\"\n" \ ".popsection") # endif #endif #define __IDSTRING(_n,_s) __SECTIONSTRING(.ident,_s) #define __RCSID(_s) __IDSTRING(rcsid,_s) #define __SCCSID(_s) #define __SCCSID2(_s) #define __COPYRIGHT(_s) __SECTIONSTRING(.copyright,_s) #define __KERNEL_RCSID(_n, _s) __RCSID(_s) #define __KERNEL_SCCSID(_n, _s) #define __KERNEL_COPYRIGHT(_n, _s) __COPYRIGHT(_s) #ifndef __lint__ #define __link_set_make_entry(set, sym) \ static void const * const __link_set_##set##_sym_##sym \ __section("link_set_" #set) __used = (const void *)&sym #define __link_set_make_entry2(set, sym, n) \ static void const * const __link_set_##set##_sym_##sym##_##n \ __section("link_set_" #set) __used = (const void *)&sym[n] #else #define __link_set_make_entry(set, sym) \ extern void const * const __link_set_##set##_sym_##sym #define __link_set_make_entry2(set, sym, n) \ extern void const * const __link_set_##set##_sym_##sym##_##n #endif /* __lint__ */ #define __link_set_add_text(set, sym) __link_set_make_entry(set, sym) #define __link_set_add_rodata(set, sym) __link_set_make_entry(set, sym) #define __link_set_add_data(set, sym) __link_set_make_entry(set, sym) #define __link_set_add_bss(set, sym) __link_set_make_entry(set, sym) #define __link_set_add_text2(set, sym, n) __link_set_make_entry2(set, sym, n) #define __link_set_add_rodata2(set, sym, n) __link_set_make_entry2(set, sym, n) #define __link_set_add_data2(set, sym, n) __link_set_make_entry2(set, sym, n) #define __link_set_add_bss2(set, sym, n) __link_set_make_entry2(set, sym, n) #define __link_set_start(set) (__start_link_set_##set) #define __link_set_end(set) (__stop_link_set_##set) #define __link_set_decl(set, ptype) \ extern ptype * const __link_set_start(set)[] __dso_hidden; \ __asm__(".hidden " __STRING(__stop_link_set_##set)); \ extern ptype * const __link_set_end(set)[] __weak __dso_hidden #define __link_set_count(set) \ (__link_set_end(set) - __link_set_start(set)) #ifdef _KERNEL /* * On multiprocessor systems we can gain an improvement in performance * by being mindful of which cachelines data is placed in. * * __read_mostly: * * It makes sense to ensure that rarely modified data is not * placed in the same cacheline as frequently modified data. * To mitigate the phenomenon known as "false-sharing" we * can annotate rarely modified variables with __read_mostly. * All such variables are placed into the .data.read_mostly * section in the kernel ELF. * * Prime candidates for __read_mostly annotation are variables * which are hardly ever modified and which are used in code * hot-paths, e.g. pmap_initialized. * * __cacheline_aligned: * * Some data structures (mainly locks) benefit from being aligned * on a cacheline boundary, and having a cacheline to themselves. * This way, the modification of other data items cannot adversely * affect the lock and vice versa. * * Any variables annotated with __cacheline_aligned will be * placed into the .data.cacheline_aligned ELF section. */ #define __read_mostly \ __attribute__((__section__(".data.read_mostly"))) #define __cacheline_aligned \ __attribute__((__aligned__(COHERENCY_UNIT), \ __section__(".data.cacheline_aligned"))) #endif /* _KERNEL */ #endif /* !_SYS_CDEFS_ELF_H_ */