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7b4537199a
include/{linux,asm-generic}/export.h defines a weak symbol, __crc_*
as a placeholder.
Genksyms writes the version CRCs into the linker script, which will be
used for filling the __crc_* symbols. The linker script format depends
on CONFIG_MODULE_REL_CRCS. If it is enabled, __crc_* holds the offset
to the reference of CRC.
It is time to get rid of this complexity.
Now that modpost parses text files (.*.cmd) to collect all the CRCs,
it can generate C code that will be linked to the vmlinux or modules.
Generate a new C file, .vmlinux.export.c, which contains the CRCs of
symbols exported by vmlinux. It is compiled and linked to vmlinux in
scripts/link-vmlinux.sh.
Put the CRCs of symbols exported by modules into the existing *.mod.c
files. No additional build step is needed for modules. As before,
*.mod.c are compiled and linked to *.ko in scripts/Makefile.modfinal.
No linker magic is used here. The new C implementation works in the
same way, whether CONFIG_RELOCATABLE is enabled or not.
CONFIG_MODULE_REL_CRCS is no longer needed.
Previously, Kbuild invoked additional $(LD) to update the CRCs in
objects, but this step is unneeded too.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Tested-by: Nathan Chancellor <nathan@kernel.org>
Tested-by: Nicolas Schier <nicolas@fjasle.eu>
Reviewed-by: Nicolas Schier <nicolas@fjasle.eu>
Tested-by: Sedat Dilek <sedat.dilek@gmail.com> # LLVM-14 (x86-64)
88 lines
2.3 KiB
C
88 lines
2.3 KiB
C
/* SPDX-License-Identifier: GPL-2.0-only */
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#ifndef __ASM_GENERIC_EXPORT_H
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#define __ASM_GENERIC_EXPORT_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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#ifndef KSYM_FUNC
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#define KSYM_FUNC(x) x
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#endif
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#ifdef CONFIG_HAVE_ARCH_PREL32_RELOCATIONS
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#define KSYM_ALIGN 4
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#elif defined(CONFIG_64BIT)
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#define KSYM_ALIGN 8
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#else
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#define KSYM_ALIGN 4
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#endif
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.macro __put, val, name
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#ifdef CONFIG_HAVE_ARCH_PREL32_RELOCATIONS
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.long \val - ., \name - ., 0
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#elif defined(CONFIG_64BIT)
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.quad \val, \name, 0
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#else
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.long \val, \name, 0
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#endif
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.endm
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/*
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* note on .section use: we specify progbits since usage of the "M" (SHF_MERGE)
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* section flag requires it. Use '%progbits' instead of '@progbits' since the
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* former apparently works on all arches according to the binutils source.
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*/
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.macro ___EXPORT_SYMBOL name,val,sec
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#if defined(CONFIG_MODULES) && !defined(__DISABLE_EXPORTS)
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.section ___ksymtab\sec+\name,"a"
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.balign KSYM_ALIGN
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__ksymtab_\name:
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__put \val, __kstrtab_\name
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.previous
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.section __ksymtab_strings,"aMS",%progbits,1
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__kstrtab_\name:
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.asciz "\name"
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.previous
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#endif
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.endm
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#if defined(CONFIG_TRIM_UNUSED_KSYMS)
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#include <linux/kconfig.h>
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#include <generated/autoksyms.h>
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.macro __ksym_marker sym
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.section ".discard.ksym","a"
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__ksym_marker_\sym:
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.previous
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.endm
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#define __EXPORT_SYMBOL(sym, val, sec) \
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__ksym_marker sym; \
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__cond_export_sym(sym, val, sec, __is_defined(__KSYM_##sym))
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#define __cond_export_sym(sym, val, sec, conf) \
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___cond_export_sym(sym, val, sec, conf)
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#define ___cond_export_sym(sym, val, sec, enabled) \
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__cond_export_sym_##enabled(sym, val, sec)
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#define __cond_export_sym_1(sym, val, sec) ___EXPORT_SYMBOL sym, val, sec
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#define __cond_export_sym_0(sym, val, sec) /* nothing */
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#else
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#define __EXPORT_SYMBOL(sym, val, sec) ___EXPORT_SYMBOL sym, val, sec
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#endif
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#define EXPORT_SYMBOL(name) \
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__EXPORT_SYMBOL(name, KSYM_FUNC(name),)
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#define EXPORT_SYMBOL_GPL(name) \
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__EXPORT_SYMBOL(name, KSYM_FUNC(name), _gpl)
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#define EXPORT_DATA_SYMBOL(name) \
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__EXPORT_SYMBOL(name, name,)
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#define EXPORT_DATA_SYMBOL_GPL(name) \
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__EXPORT_SYMBOL(name, name,_gpl)
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#endif
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