[mirror_ubuntu-bionic-kernel.git] / include / linux / export.h

#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), used))	\
	= (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);					\
	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 */
Commit	Line	Data
f5016932 PG	1	#ifndef _LINUX_EXPORT_H
f5016932 PG	2	#define _LINUX_EXPORT_H
b67067f1	3
f5016932 PG	4	/*
	5	* Export symbols from the kernel to modules. Forked from module.h
	6	* to reduce the amount of pointless cruft we feed to gcc when only
	7	* exporting a simple symbol or two.
	8	*
b92021b0 RR	9	* Try not to add #includes here. It slows compilation and makes kernel
b92021b0 RR	10	* hackers place grumpy comments in header files.
f5016932 PG	11	*/
	12
	13	/* Some toolchains use a `_' prefix for all user symbols. */
b92021b0 RR	14	#ifdef CONFIG_HAVE_UNDERSCORE_SYMBOL_PREFIX
	15	#define __VMLINUX_SYMBOL(x) _##x
	16	#define __VMLINUX_SYMBOL_STR(x) "_" #x
f5016932	17	#else
b92021b0 RR	18	#define __VMLINUX_SYMBOL(x) x
b92021b0 RR	19	#define __VMLINUX_SYMBOL_STR(x) #x
f5016932 PG	20	#endif
f5016932 PG	21
b92021b0 RR	22	/* Indirect, so macros are expanded before pasting. */
	23	#define VMLINUX_SYMBOL(x) __VMLINUX_SYMBOL(x)
	24	#define VMLINUX_SYMBOL_STR(x) __VMLINUX_SYMBOL_STR(x)
	25
	26	#ifndef __ASSEMBLY__
f5016932 PG	27	struct kernel_symbol
	28	{
	29	unsigned long value;
	30	const char *name;
	31	};
	32
	33	#ifdef MODULE
	34	extern struct module __this_module;
	35	#define THIS_MODULE (&__this_module)
	36	#else
	37	#define THIS_MODULE ((struct module *)0)
	38	#endif
	39
	40	#ifdef CONFIG_MODULES
	41
f2355416	42	#if defined(__KERNEL__) && !defined(__GENKSYMS__)
f5016932 PG	43	#ifdef CONFIG_MODVERSIONS
	44	/* Mark the CRC weak since genksyms apparently decides not to
	45	* generate a checksums for some symbols */
b67067f1 NP	46	#define __CRC_SYMBOL(sym, sec) \
	47	extern __visible void *__crc_##sym __attribute__((weak)); \
	48	static const unsigned long __kcrctab_##sym \
	49	__used \
	50	__attribute__((section("___kcrctab" sec "+" #sym), used)) \
f5016932 PG	51	= (unsigned long) &__crc_##sym;
	52	#else
	53	#define __CRC_SYMBOL(sym, sec)
	54	#endif
	55
	56	/* For every exported symbol, place a struct in the __ksymtab section */
b67067f1 NP	57	#define ___EXPORT_SYMBOL(sym, sec) \
	58	extern typeof(sym) sym; \
	59	__CRC_SYMBOL(sym, sec) \
	60	static const char __kstrtab_##sym[] \
	61	__attribute__((section("__ksymtab_strings"), aligned(1))) \
	62	= VMLINUX_SYMBOL_STR(sym); \
	63	static const struct kernel_symbol __ksymtab_##sym \
	64	__used \
	65	__attribute__((section("___ksymtab" sec "+" #sym), used)) \
f5016932 PG	66	= { (unsigned long)&sym, __kstrtab_##sym }
f5016932 PG	67
c1a95fda NP	68	#if defined(__KSYM_DEPS__)
	69
	70	/*
	71	* For fine grained build dependencies, we want to tell the build system
	72	* about each possible exported symbol even if they're not actually exported.
	73	* We use a string pattern that is unlikely to be valid code that the build
	74	* system filters out from the preprocessor output (see ksym_dep_filter
	75	* in scripts/Kbuild.include).
	76	*/
	77	#define __EXPORT_SYMBOL(sym, sec) === __KSYM_##sym ===
	78
	79	#elif defined(CONFIG_TRIM_UNUSED_KSYMS)
f2355416	80
f2355416 NP	81	#include <generated/autoksyms.h>
	82
	83	#define __EXPORT_SYMBOL(sym, sec) \
6023d236	84	__cond_export_sym(sym, sec, __is_defined(__KSYM_##sym))
f2355416 NP	85	#define __cond_export_sym(sym, sec, conf) \
	86	___cond_export_sym(sym, sec, conf)
	87	#define ___cond_export_sym(sym, sec, enabled) \
	88	__cond_export_sym_##enabled(sym, sec)
	89	#define __cond_export_sym_1(sym, sec) ___EXPORT_SYMBOL(sym, sec)
	90	#define __cond_export_sym_0(sym, sec) /* nothing */
	91
	92	#else
	93	#define __EXPORT_SYMBOL ___EXPORT_SYMBOL
	94	#endif
	95
f5016932 PG	96	#define EXPORT_SYMBOL(sym) \
	97	__EXPORT_SYMBOL(sym, "")
	98
	99	#define EXPORT_SYMBOL_GPL(sym) \
	100	__EXPORT_SYMBOL(sym, "_gpl")
	101
	102	#define EXPORT_SYMBOL_GPL_FUTURE(sym) \
	103	__EXPORT_SYMBOL(sym, "_gpl_future")
	104
	105	#ifdef CONFIG_UNUSED_SYMBOLS
	106	#define EXPORT_UNUSED_SYMBOL(sym) __EXPORT_SYMBOL(sym, "_unused")
	107	#define EXPORT_UNUSED_SYMBOL_GPL(sym) __EXPORT_SYMBOL(sym, "_unused_gpl")
	108	#else
	109	#define EXPORT_UNUSED_SYMBOL(sym)
	110	#define EXPORT_UNUSED_SYMBOL_GPL(sym)
	111	#endif
	112
	113	#endif /* __GENKSYMS__ */
	114
	115	#else /* !CONFIG_MODULES... */
	116
	117	#define EXPORT_SYMBOL(sym)
	118	#define EXPORT_SYMBOL_GPL(sym)
	119	#define EXPORT_SYMBOL_GPL_FUTURE(sym)
	120	#define EXPORT_UNUSED_SYMBOL(sym)
	121	#define EXPORT_UNUSED_SYMBOL_GPL(sym)
	122
	123	#endif /* CONFIG_MODULES */
b92021b0	124	#endif /* !__ASSEMBLY__ */
f5016932 PG	125
f5016932 PG	126	#endif /* _LINUX_EXPORT_H */