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linux-next/include/linux/export.h
Masahiro Yamada 6023d2369b export.h: use __is_defined() to check if __KSYM_* is defined
Here the need is for a macro that checks whether the given symbol is
defined or not, which has nothing to do with config.

The new macro __is_defined() is a better fit for this case.

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Acked-by: Nicolas Pitre <nico@linaro.org>
Signed-off-by: Michal Marek <mmarek@suse.com>
2016-06-20 22:42:32 +02:00

128 lines
3.7 KiB
C

#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 */
#define __CRC_SYMBOL(sym, sec) \
extern __visible void *__crc_##sym __attribute__((weak)); \
static const unsigned long __kcrctab_##sym \
__used \
__attribute__((section("___kcrctab" sec "+" #sym), unused)) \
= (unsigned long) &__crc_##sym;
#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); \
extern const struct kernel_symbol __ksymtab_##sym; \
__visible const struct kernel_symbol __ksymtab_##sym \
__used \
__attribute__((section("___ksymtab" sec "+" #sym), unused)) \
= { (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 <linux/kconfig.h>
#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 */