forked from mirrors/linux
4b9eee96fc
The previous patch introduced a separate inline asm version of the krcrctab declaration template for use with 64-bit architectures, which cannot refer to ELF symbols using 32-bit quantities. This declaration should be equivalent to the C one for 32-bit architectures, but just in case - unify them in a separate patch, which can simply be dropped if it turns out to break anything. Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
133 lines
3.9 KiB
C
133 lines
3.9 KiB
C
#ifndef _LINUX_EXPORT_H
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#define _LINUX_EXPORT_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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/* Some toolchains use a `_' prefix for all user symbols. */
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#ifdef CONFIG_HAVE_UNDERSCORE_SYMBOL_PREFIX
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#define __VMLINUX_SYMBOL(x) _##x
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#define __VMLINUX_SYMBOL_STR(x) "_" #x
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#else
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#define __VMLINUX_SYMBOL(x) x
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#define __VMLINUX_SYMBOL_STR(x) #x
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#endif
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/* Indirect, so macros are expanded before pasting. */
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#define VMLINUX_SYMBOL(x) __VMLINUX_SYMBOL(x)
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#define VMLINUX_SYMBOL_STR(x) __VMLINUX_SYMBOL_STR(x)
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#ifndef __ASSEMBLY__
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struct kernel_symbol
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{
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unsigned long value;
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const char *name;
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};
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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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#ifdef CONFIG_MODULES
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#if defined(__KERNEL__) && !defined(__GENKSYMS__)
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#ifdef CONFIG_MODVERSIONS
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/* Mark the CRC weak since genksyms apparently decides not to
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* generate a checksums for some symbols */
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#if defined(CONFIG_MODULE_REL_CRCS)
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#define __CRC_SYMBOL(sym, sec) \
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asm(" .section \"___kcrctab" sec "+" #sym "\", \"a\" \n" \
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" .weak " VMLINUX_SYMBOL_STR(__crc_##sym) " \n" \
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" .long " VMLINUX_SYMBOL_STR(__crc_##sym) " - . \n" \
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" .previous \n");
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#else
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#define __CRC_SYMBOL(sym, sec) \
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asm(" .section \"___kcrctab" sec "+" #sym "\", \"a\" \n" \
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" .weak " VMLINUX_SYMBOL_STR(__crc_##sym) " \n" \
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" .long " VMLINUX_SYMBOL_STR(__crc_##sym) " \n" \
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" .previous \n");
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#endif
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#else
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#define __CRC_SYMBOL(sym, sec)
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#endif
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/* For every exported symbol, place a struct in the __ksymtab section */
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#define ___EXPORT_SYMBOL(sym, sec) \
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extern typeof(sym) sym; \
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__CRC_SYMBOL(sym, sec) \
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static const char __kstrtab_##sym[] \
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__attribute__((section("__ksymtab_strings"), aligned(1))) \
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= VMLINUX_SYMBOL_STR(sym); \
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static const struct kernel_symbol __ksymtab_##sym \
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__used \
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__attribute__((section("___ksymtab" sec "+" #sym), used)) \
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= { (unsigned long)&sym, __kstrtab_##sym }
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#if defined(__KSYM_DEPS__)
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/*
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* For fine grained build dependencies, we want to tell the build system
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* about each possible exported symbol even if they're not actually exported.
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* We use a string pattern that is unlikely to be valid code that the build
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* system filters out from the preprocessor output (see ksym_dep_filter
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* in scripts/Kbuild.include).
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*/
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#define __EXPORT_SYMBOL(sym, sec) === __KSYM_##sym ===
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#elif defined(CONFIG_TRIM_UNUSED_KSYMS)
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#include <generated/autoksyms.h>
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#define __EXPORT_SYMBOL(sym, sec) \
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__cond_export_sym(sym, sec, __is_defined(__KSYM_##sym))
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#define __cond_export_sym(sym, sec, conf) \
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___cond_export_sym(sym, sec, conf)
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#define ___cond_export_sym(sym, sec, enabled) \
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__cond_export_sym_##enabled(sym, sec)
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#define __cond_export_sym_1(sym, sec) ___EXPORT_SYMBOL(sym, sec)
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#define __cond_export_sym_0(sym, sec) /* nothing */
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#else
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#define __EXPORT_SYMBOL ___EXPORT_SYMBOL
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#endif
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#define EXPORT_SYMBOL(sym) \
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__EXPORT_SYMBOL(sym, "")
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#define EXPORT_SYMBOL_GPL(sym) \
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__EXPORT_SYMBOL(sym, "_gpl")
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#define EXPORT_SYMBOL_GPL_FUTURE(sym) \
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__EXPORT_SYMBOL(sym, "_gpl_future")
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#ifdef CONFIG_UNUSED_SYMBOLS
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#define EXPORT_UNUSED_SYMBOL(sym) __EXPORT_SYMBOL(sym, "_unused")
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#define EXPORT_UNUSED_SYMBOL_GPL(sym) __EXPORT_SYMBOL(sym, "_unused_gpl")
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#else
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#define EXPORT_UNUSED_SYMBOL(sym)
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#define EXPORT_UNUSED_SYMBOL_GPL(sym)
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#endif
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#endif /* __GENKSYMS__ */
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#else /* !CONFIG_MODULES... */
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#define EXPORT_SYMBOL(sym)
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#define EXPORT_SYMBOL_GPL(sym)
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#define EXPORT_SYMBOL_GPL_FUTURE(sym)
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#define EXPORT_UNUSED_SYMBOL(sym)
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#define EXPORT_UNUSED_SYMBOL_GPL(sym)
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#endif /* CONFIG_MODULES */
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#endif /* !__ASSEMBLY__ */
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#endif /* _LINUX_EXPORT_H */
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