forked from mirrors/linux
481461f510
Currently, all files with EXPORT_SYMBOL() are rebuilt when CONFIG_MODULES is flipped due to <linux/export.h> depending on CONFIG_MODULES. Now that modpost can make a final decision about export symbols, <linux/export.h> does not need to make EXPORT_SYMBOL() no-op. Instead, modpost can skip emitting KSYMTAB when CONFIG_MODULES is unset. This commit will reduce the number of recompilation when CONFIG_MODULES is toggled. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
91 lines
2.4 KiB
C
91 lines
2.4 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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* Export symbols from the kernel to modules. Forked from module.h
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* to reduce the amount of pointless cruft we feed to gcc when only
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* exporting a simple symbol or two.
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*
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* Try not to add #includes here. It slows compilation and makes kernel
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* hackers place grumpy comments in header files.
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*/
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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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#ifndef __ASSEMBLY__
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#ifdef MODULE
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extern struct module __this_module;
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#define THIS_MODULE (&__this_module)
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#else
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#define THIS_MODULE ((struct module *)0)
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#endif
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#endif /* __ASSEMBLY__ */
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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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#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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.asciz ns 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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#define __EXPORT_SYMBOL(sym, license, ns) \
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extern typeof(sym) sym; \
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__ADDRESSABLE(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, __stringify(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, "", __stringify(ns))
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#define EXPORT_SYMBOL_NS_GPL(sym, ns) __EXPORT_SYMBOL(sym, "GPL", __stringify(ns))
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#endif /* _LINUX_EXPORT_H */
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