cregit-Linux how code gets into the kernel

Release 4.15 include/linux/export.h

Directory: include/linux
#ifndef _LINUX_EXPORT_H

#define _LINUX_EXPORT_H

/*
 * Export symbols from the kernel to modules.  Forked from module.h
 * to reduce the amount of pointless cruft we feed to gcc when only
 * exporting a simple symbol or two.
 *
 * Try not to add #includes here.  It slows compilation and makes kernel
 * hackers place grumpy comments in header files.
 */

/* Some toolchains use a `_' prefix for all user symbols. */
#ifdef CONFIG_HAVE_UNDERSCORE_SYMBOL_PREFIX

#define __VMLINUX_SYMBOL(x) _##x

#define __VMLINUX_SYMBOL_STR(x) "_" #x
#else

#define __VMLINUX_SYMBOL(x) x

#define __VMLINUX_SYMBOL_STR(x) #x
#endif

/* Indirect, so macros are expanded before pasting. */

#define VMLINUX_SYMBOL(x) __VMLINUX_SYMBOL(x)

#define VMLINUX_SYMBOL_STR(x) __VMLINUX_SYMBOL_STR(x)

#ifndef __ASSEMBLY__

struct kernel_symbol
{
	
unsigned long value;
	
const char *name;
};

#ifdef MODULE
extern struct module __this_module;

#define THIS_MODULE (&__this_module)
#else

#define THIS_MODULE ((struct module *)0)
#endif

#ifdef CONFIG_MODULES

#if defined(__KERNEL__) && !defined(__GENKSYMS__)
#ifdef CONFIG_MODVERSIONS
/* Mark the CRC weak since genksyms apparently decides not to
 * generate a checksums for some symbols */
#if defined(CONFIG_MODULE_REL_CRCS)

#define __CRC_SYMBOL(sym, sec)						\
	asm("   .section \"___kcrctab" sec "+" #sym "\", \"a\"  \n"     \
            "   .weak   " VMLINUX_SYMBOL_STR(__crc_##sym) "     \n"     \
            "   .long   " VMLINUX_SYMBOL_STR(__crc_##sym) " - . \n"     \
            "   .previous                                       \n");
#else

#define __CRC_SYMBOL(sym, sec)						\
	asm("   .section \"___kcrctab" sec "+" #sym "\", \"a\"  \n"     \
            "   .weak   " VMLINUX_SYMBOL_STR(__crc_##sym) "     \n"     \
            "   .long   " VMLINUX_SYMBOL_STR(__crc_##sym) "     \n"     \
            "   .previous                                       \n");
#endif
#else

#define __CRC_SYMBOL(sym, sec)
#endif

/* For every exported symbol, place a struct in the __ksymtab section */

#define ___EXPORT_SYMBOL(sym, sec)					\
	extern typeof(sym) sym;                                         \
        __CRC_SYMBOL(sym, sec)                                          \
        static const char __kstrtab_##sym[]                             \
        __attribute__((section("__ksymtab_strings"), aligned(1)))       \
        = VMLINUX_SYMBOL_STR(sym);                                      \
        static const struct kernel_symbol __ksymtab_##sym               \
        __used                                                          \
        __attribute__((section("___ksymtab" sec "+" #sym), used))       \
        = { (unsigned long)&sym, __kstrtab_##sym }

#if defined(__KSYM_DEPS__)

/*
 * For fine grained build dependencies, we want to tell the build system
 * about each possible exported symbol even if they're not actually exported.
 * We use a string pattern that is unlikely to be valid code that the build
 * system filters out from the preprocessor output (see ksym_dep_filter
 * in scripts/Kbuild.include).
 */

#define __EXPORT_SYMBOL(sym, sec)	=== __KSYM_##sym ===

#elif defined(CONFIG_TRIM_UNUSED_KSYMS)

#include <generated/autoksyms.h>


#define __EXPORT_SYMBOL(sym, sec)				\
	__cond_export_sym(sym, sec, __is_defined(__KSYM_##sym))

#define __cond_export_sym(sym, sec, conf)			\
	___cond_export_sym(sym, sec, conf)

#define ___cond_export_sym(sym, sec, enabled)			\
	__cond_export_sym_##enabled(sym, sec)

#define __cond_export_sym_1(sym, sec) ___EXPORT_SYMBOL(sym, sec)

#define __cond_export_sym_0(sym, sec) 
/* nothing */

#else

#define __EXPORT_SYMBOL ___EXPORT_SYMBOL
#endif


#define EXPORT_SYMBOL(sym)					\
	__EXPORT_SYMBOL(sym, "")


#define EXPORT_SYMBOL_GPL(sym)					\
	__EXPORT_SYMBOL(sym, "_gpl")


#define EXPORT_SYMBOL_GPL_FUTURE(sym)				\
	__EXPORT_SYMBOL(sym, "_gpl_future")

#ifdef CONFIG_UNUSED_SYMBOLS

#define EXPORT_UNUSED_SYMBOL(sym) __EXPORT_SYMBOL(sym, "_unused")

#define EXPORT_UNUSED_SYMBOL_GPL(sym) __EXPORT_SYMBOL(sym, "_unused_gpl")
#else

#define EXPORT_UNUSED_SYMBOL(sym)

#define EXPORT_UNUSED_SYMBOL_GPL(sym)
#endif

#endif	/* __GENKSYMS__ */

#else /* !CONFIG_MODULES... */


#define EXPORT_SYMBOL(sym)

#define EXPORT_SYMBOL_GPL(sym)

#define EXPORT_SYMBOL_GPL_FUTURE(sym)

#define EXPORT_UNUSED_SYMBOL(sym)

#define EXPORT_UNUSED_SYMBOL_GPL(sym)

#endif /* CONFIG_MODULES */
#endif /* !__ASSEMBLY__ */

#endif /* _LINUX_EXPORT_H */

Overall Contributors

PersonTokensPropCommitsCommitProp
Paul Gortmaker18050.85%114.29%
Nico Pitre9526.84%228.57%
Rusty Russell4713.28%114.29%
Ard Biesheuvel308.47%114.29%
Masahiro Yamada10.28%114.29%
Nicholas Piggin10.28%114.29%
Total354100.00%7100.00%
Directory: include/linux
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