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https://git.kernel.org/pub/scm/linux/kernel/git/chenhuacai/linux-loongson
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707f853d7f
Helper macro to more easily limit the export of a symbol to a given list of modules. Eg: EXPORT_SYMBOL_GPL_FOR_MODULES(preempt_notifier_inc, "kvm"); will limit the use of said function to kvm.ko, any other module trying to use this symbol will refure to load (and get modpost build failures). Requested-by: Masahiro Yamada <masahiroy@kernel.org> Requested-by: Christoph Hellwig <hch@infradead.org> Signed-off-by: Peter Zijlstra <peterz@infradead.org> Reviewed-by: Petr Pavlu <petr.pavlu@suse.com> Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
97 lines
2.7 KiB
C
97 lines
2.7 KiB
C
/* SPDX-License-Identifier: GPL-2.0-only */
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#ifndef _LINUX_EXPORT_H
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#define _LINUX_EXPORT_H
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#include <linux/compiler.h>
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#include <linux/linkage.h>
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#include <linux/stringify.h>
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/*
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* This comment block is used by fixdep. Please do not remove.
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*
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* When CONFIG_MODVERSIONS is changed from n to y, all source files having
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* EXPORT_SYMBOL variants must be re-compiled because genksyms is run as a
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* side effect of the *.o build rule.
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*/
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#ifdef CONFIG_64BIT
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#define __EXPORT_SYMBOL_REF(sym) \
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.balign 8 ASM_NL \
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.quad sym
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#else
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#define __EXPORT_SYMBOL_REF(sym) \
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.balign 4 ASM_NL \
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.long sym
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#endif
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/*
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* LLVM integrated assembler cam merge adjacent string literals (like
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* C and GNU-as) passed to '.ascii', but not to '.asciz' and chokes on:
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*
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* .asciz "MODULE_" "kvm" ;
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*/
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#define ___EXPORT_SYMBOL(sym, license, ns...) \
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.section ".export_symbol","a" ASM_NL \
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__export_symbol_##sym: ASM_NL \
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.asciz license ASM_NL \
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.ascii ns "\0" ASM_NL \
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__EXPORT_SYMBOL_REF(sym) ASM_NL \
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.previous
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#if defined(__DISABLE_EXPORTS)
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/*
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* Allow symbol exports to be disabled completely so that C code may
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* be reused in other execution contexts such as the UEFI stub or the
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* decompressor.
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*/
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#define __EXPORT_SYMBOL(sym, license, ns)
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#elif defined(__GENKSYMS__)
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#define __EXPORT_SYMBOL(sym, license, ns) __GENKSYMS_EXPORT_SYMBOL(sym)
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#elif defined(__ASSEMBLY__)
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#define __EXPORT_SYMBOL(sym, license, ns) \
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___EXPORT_SYMBOL(sym, license, ns)
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#else
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#ifdef CONFIG_GENDWARFKSYMS
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/*
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* With CONFIG_GENDWARFKSYMS, ensure the compiler emits debugging
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* information for all exported symbols, including those defined in
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* different TUs, by adding a __gendwarfksyms_ptr_<symbol> pointer
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* that's discarded during the final link.
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*/
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#define __GENDWARFKSYMS_EXPORT(sym) \
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static typeof(sym) *__gendwarfksyms_ptr_##sym __used \
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__section(".discard.gendwarfksyms") = &sym;
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#else
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#define __GENDWARFKSYMS_EXPORT(sym)
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#endif
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#define __EXPORT_SYMBOL(sym, license, ns) \
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extern typeof(sym) sym; \
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__ADDRESSABLE(sym) \
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__GENDWARFKSYMS_EXPORT(sym) \
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asm(__stringify(___EXPORT_SYMBOL(sym, license, ns)))
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#endif
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#ifdef DEFAULT_SYMBOL_NAMESPACE
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#define _EXPORT_SYMBOL(sym, license) __EXPORT_SYMBOL(sym, license, DEFAULT_SYMBOL_NAMESPACE)
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#else
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#define _EXPORT_SYMBOL(sym, license) __EXPORT_SYMBOL(sym, license, "")
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#endif
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#define EXPORT_SYMBOL(sym) _EXPORT_SYMBOL(sym, "")
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#define EXPORT_SYMBOL_GPL(sym) _EXPORT_SYMBOL(sym, "GPL")
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#define EXPORT_SYMBOL_NS(sym, ns) __EXPORT_SYMBOL(sym, "", ns)
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#define EXPORT_SYMBOL_NS_GPL(sym, ns) __EXPORT_SYMBOL(sym, "GPL", ns)
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#define EXPORT_SYMBOL_GPL_FOR_MODULES(sym, mods) __EXPORT_SYMBOL(sym, "GPL", "module:" mods)
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#endif /* _LINUX_EXPORT_H */
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