[mirror_ubuntu-focal-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.
 */

#ifndef __ASSEMBLY__
#ifdef MODULE
extern struct module __this_module;
#define THIS_MODULE (&__this_module)
#else
#define THIS_MODULE ((struct module *)0)
#endif

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

#ifdef CONFIG_HAVE_ARCH_PREL32_RELOCATIONS
#include <linux/compiler.h>
/*
 * Emit the ksymtab entry as a pair of relative references: this reduces
 * the size by half on 64-bit architectures, and eliminates the need for
 * absolute relocations that require runtime processing on relocatable
 * kernels.
 */
#define __KSYMTAB_ENTRY_NS(sym, sec)					\
	__ADDRESSABLE(sym)						\
	asm("	.section \"___ksymtab" sec "+" #sym "\", \"a\"	\n"	\
	    "	.balign	4					\n"	\
	    "__ksymtab_" #sym ":				\n"	\
	    "	.long	" #sym "- .				\n"	\
	    "	.long	__kstrtab_" #sym "- .			\n"	\
	    "	.long	__kstrtabns_" #sym "- .			\n"	\
	    "	.previous					\n")

#define __KSYMTAB_ENTRY(sym, sec)					\
	__ADDRESSABLE(sym)						\
	asm("	.section \"___ksymtab" sec "+" #sym "\", \"a\"	\n"	\
	    "	.balign 4					\n"	\
	    "__ksymtab_" #sym ":				\n"	\
	    "	.long	" #sym "- .				\n"	\
	    "	.long	__kstrtab_" #sym "- .			\n"	\
	    "	.long	0					\n"	\
	    "	.previous					\n")

struct kernel_symbol {
	int value_offset;
	int name_offset;
	int namespace_offset;
};
#else
#define __KSYMTAB_ENTRY_NS(sym, sec)					\
	static const struct kernel_symbol __ksymtab_##sym		\
	__attribute__((section("___ksymtab" sec "+" #sym), used))	\
	__aligned(sizeof(void *))					\
	= { (unsigned long)&sym, __kstrtab_##sym, __kstrtabns_##sym }

#define __KSYMTAB_ENTRY(sym, sec)					\
	static const struct kernel_symbol __ksymtab_##sym		\
	__attribute__((section("___ksymtab" sec "+" #sym), used))	\
	__aligned(sizeof(void *))					\
	= { (unsigned long)&sym, __kstrtab_##sym, NULL }

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

#ifdef __GENKSYMS__

#define ___EXPORT_SYMBOL(sym,sec)	__GENKSYMS_EXPORT_SYMBOL(sym)
#define ___EXPORT_SYMBOL_NS(sym,sec,ns)	__GENKSYMS_EXPORT_SYMBOL(sym)

#else

#define ___export_symbol_common(sym, sec)				\
	extern typeof(sym) sym;						\
	__CRC_SYMBOL(sym, sec);						\
	static const char __kstrtab_##sym[]				\
	__attribute__((section("__ksymtab_strings"), used, aligned(1)))	\
	= #sym								\

/* For every exported symbol, place a struct in the __ksymtab section */
#define ___EXPORT_SYMBOL_NS(sym, sec, ns)				\
	___export_symbol_common(sym, sec);				\
	static const char __kstrtabns_##sym[]				\
	__attribute__((section("__ksymtab_strings"), used, aligned(1)))	\
	= #ns;								\
	__KSYMTAB_ENTRY_NS(sym, sec)

#define ___EXPORT_SYMBOL(sym, sec)					\
	___export_symbol_common(sym, sec);				\
	__KSYMTAB_ENTRY(sym, sec)

#endif

#if !defined(CONFIG_MODULES) || defined(__DISABLE_EXPORTS)

/*
 * Allow symbol exports to be disabled completely so that C code may
 * be reused in other execution contexts such as the UEFI stub or the
 * decompressor.
 */
#define __EXPORT_SYMBOL_NS(sym, sec, ns)
#define __EXPORT_SYMBOL(sym, sec)

#elif defined(CONFIG_TRIM_UNUSED_KSYMS)

#include <generated/autoksyms.h>

/*
 * 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 symbol pattern __ksym_marker_<symbol> that the build system filters
 * from the $(NM) output (see scripts/gen_ksymdeps.sh). These symbols are
 * discarded in the final link stage.
 */
#define __ksym_marker(sym)	\
	static int __ksym_marker_##sym[0] __section(".discard.ksym") __used

#define __EXPORT_SYMBOL(sym, sec)				\
	__ksym_marker(sym);					\
	__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 */

#define __EXPORT_SYMBOL_NS(sym, sec, ns)				\
	__ksym_marker(sym);						\
	__cond_export_ns_sym(sym, sec, ns, __is_defined(__KSYM_##sym))
#define __cond_export_ns_sym(sym, sec, ns, conf)			\
	___cond_export_ns_sym(sym, sec, ns, conf)
#define ___cond_export_ns_sym(sym, sec, ns, enabled)			\
	__cond_export_ns_sym_##enabled(sym, sec, ns)
#define __cond_export_ns_sym_1(sym, sec, ns) ___EXPORT_SYMBOL_NS(sym, sec, ns)
#define __cond_export_ns_sym_0(sym, sec, ns) /* nothing */

#else

#define __EXPORT_SYMBOL_NS(sym,sec,ns)	___EXPORT_SYMBOL_NS(sym,sec,ns)
#define __EXPORT_SYMBOL(sym,sec)	___EXPORT_SYMBOL(sym,sec)

#endif /* CONFIG_MODULES */

#ifdef DEFAULT_SYMBOL_NAMESPACE
#undef __EXPORT_SYMBOL
#define __EXPORT_SYMBOL(sym, sec)				\
	__EXPORT_SYMBOL_NS(sym, sec, DEFAULT_SYMBOL_NAMESPACE)
#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")
#define EXPORT_SYMBOL_NS(sym, ns)	__EXPORT_SYMBOL_NS(sym, "", ns)
#define EXPORT_SYMBOL_NS_GPL(sym, ns)	__EXPORT_SYMBOL_NS(sym, "_gpl", ns)

#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 /* !__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	*/
f5016932 PG	12
b92021b0	13	#ifndef __ASSEMBLY__
f5016932 PG	14	#ifdef MODULE
	15	extern struct module __this_module;
	16	#define THIS_MODULE (&__this_module)
	17	#else
	18	#define THIS_MODULE ((struct module *)0)
	19	#endif
	20
f5016932 PG	21	#ifdef CONFIG_MODVERSIONS
	22	/* Mark the CRC weak since genksyms apparently decides not to
	23	* generate a checksums for some symbols */
71810db2 AB	24	#if defined(CONFIG_MODULE_REL_CRCS)
	25	#define __CRC_SYMBOL(sym, sec) \
	26	asm(" .section \"___kcrctab" sec "+" #sym "\", \"a\" \n" \
94e58e0a MY	27	" .weak __crc_" #sym " \n" \
94e58e0a MY	28	" .long __crc_" #sym " - . \n" \
8651ec01	29	" .previous \n")
f5016932	30	#else
71810db2 AB	31	#define __CRC_SYMBOL(sym, sec) \
71810db2 AB	32	asm(" .section \"___kcrctab" sec "+" #sym "\", \"a\" \n" \
94e58e0a MY	33	" .weak __crc_" #sym " \n" \
94e58e0a MY	34	" .long __crc_" #sym " \n" \
8651ec01	35	" .previous \n")
71810db2 AB	36	#endif
71810db2 AB	37	#else
f5016932 PG	38	#define __CRC_SYMBOL(sym, sec)
	39	#endif
	40
7290d580 AB	41	#ifdef CONFIG_HAVE_ARCH_PREL32_RELOCATIONS
	42	#include <linux/compiler.h>
	43	/*
	44	* Emit the ksymtab entry as a pair of relative references: this reduces
	45	* the size by half on 64-bit architectures, and eliminates the need for
	46	* absolute relocations that require runtime processing on relocatable
	47	* kernels.
	48	*/
69923208	49	#define __KSYMTAB_ENTRY_NS(sym, sec) \
8651ec01 MM	50	__ADDRESSABLE(sym) \
	51	asm(" .section \"___ksymtab" sec "+" #sym "\", \"a\" \n" \
	52	" .balign 4 \n" \
69923208	53	"__ksymtab_" #sym ": \n" \
8651ec01 MM	54	" .long " #sym "- . \n" \
8651ec01 MM	55	" .long __kstrtab_" #sym "- . \n" \
fa6643cd	56	" .long __kstrtabns_" #sym "- . \n" \
8651ec01 MM	57	" .previous \n")
8651ec01 MM	58
7290d580 AB	59	#define __KSYMTAB_ENTRY(sym, sec) \
	60	__ADDRESSABLE(sym) \
	61	asm(" .section \"___ksymtab" sec "+" #sym "\", \"a\" \n" \
ed13fc33	62	" .balign 4 \n" \
7290d580 AB	63	"__ksymtab_" #sym ": \n" \
	64	" .long " #sym "- . \n" \
	65	" .long __kstrtab_" #sym "- . \n" \
069e1c07	66	" .long 0 \n" \
7290d580 AB	67	" .previous \n")
	68
	69	struct kernel_symbol {
	70	int value_offset;
	71	int name_offset;
8651ec01	72	int namespace_offset;
7290d580 AB	73	};
7290d580 AB	74	#else
69923208 MM	75	#define __KSYMTAB_ENTRY_NS(sym, sec) \
69923208 MM	76	static const struct kernel_symbol __ksymtab_##sym \
8651ec01 MM	77	__attribute__((section("___ksymtab" sec "+" #sym), used)) \
8651ec01 MM	78	__aligned(sizeof(void *)) \
fa6643cd	79	= { (unsigned long)&sym, __kstrtab_##sym, __kstrtabns_##sym }
8651ec01	80
7290d580 AB	81	#define __KSYMTAB_ENTRY(sym, sec) \
	82	static const struct kernel_symbol __ksymtab_##sym \
	83	__attribute__((section("___ksymtab" sec "+" #sym), used)) \
ed13fc33	84	__aligned(sizeof(void *)) \
8651ec01	85	= { (unsigned long)&sym, __kstrtab_##sym, NULL }
7290d580 AB	86
	87	struct kernel_symbol {
	88	unsigned long value;
	89	const char *name;
8651ec01	90	const char *namespace;
7290d580 AB	91	};
	92	#endif
	93
69a94abb MY	94	#ifdef __GENKSYMS__
69a94abb MY	95
e0703556 LT	96	#define ___EXPORT_SYMBOL(sym,sec) __GENKSYMS_EXPORT_SYMBOL(sym)
e0703556 LT	97	#define ___EXPORT_SYMBOL_NS(sym,sec,ns) __GENKSYMS_EXPORT_SYMBOL(sym)
69a94abb MY	98
	99	#else
	100
8651ec01	101	#define ___export_symbol_common(sym, sec) \
b67067f1	102	extern typeof(sym) sym; \
8651ec01	103	__CRC_SYMBOL(sym, sec); \
b67067f1	104	static const char __kstrtab_##sym[] \
7290d580	105	__attribute__((section("__ksymtab_strings"), used, aligned(1))) \
8651ec01 MM	106	= #sym \
	107
	108	/* For every exported symbol, place a struct in the __ksymtab section */
	109	#define ___EXPORT_SYMBOL_NS(sym, sec, ns) \
	110	___export_symbol_common(sym, sec); \
fa6643cd	111	static const char __kstrtabns_##sym[] \
8651ec01 MM	112	__attribute__((section("__ksymtab_strings"), used, aligned(1))) \
8651ec01 MM	113	= #ns; \
69923208	114	__KSYMTAB_ENTRY_NS(sym, sec)
8651ec01 MM	115
	116	#define ___EXPORT_SYMBOL(sym, sec) \
	117	___export_symbol_common(sym, sec); \
7290d580	118	__KSYMTAB_ENTRY(sym, sec)
f5016932	119
69a94abb MY	120	#endif
	121
	122	#if !defined(CONFIG_MODULES) \|\| defined(__DISABLE_EXPORTS)
f922c4ab AB	123
	124	/*
	125	* Allow symbol exports to be disabled completely so that C code may
	126	* be reused in other execution contexts such as the UEFI stub or the
	127	* decompressor.
	128	*/
8651ec01	129	#define __EXPORT_SYMBOL_NS(sym, sec, ns)
f922c4ab AB	130	#define __EXPORT_SYMBOL(sym, sec)
f922c4ab AB	131
bbda5ec6 MY	132	#elif defined(CONFIG_TRIM_UNUSED_KSYMS)
	133
	134	#include <generated/autoksyms.h>
c1a95fda NP	135
	136	/*
	137	* For fine grained build dependencies, we want to tell the build system
	138	* about each possible exported symbol even if they're not actually exported.
bbda5ec6 MY	139	* We use a symbol pattern __ksym_marker_<symbol> that the build system filters
	140	* from the $(NM) output (see scripts/gen_ksymdeps.sh). These symbols are
	141	* discarded in the final link stage.
c1a95fda	142	*/
bbda5ec6 MY	143	#define __ksym_marker(sym) \
bbda5ec6 MY	144	static int __ksym_marker_##sym[0] __section(".discard.ksym") __used
f2355416 NP	145
f2355416 NP	146	#define __EXPORT_SYMBOL(sym, sec) \
bbda5ec6	147	__ksym_marker(sym); \
6023d236	148	__cond_export_sym(sym, sec, __is_defined(__KSYM_##sym))
f2355416 NP	149	#define __cond_export_sym(sym, sec, conf) \
	150	___cond_export_sym(sym, sec, conf)
	151	#define ___cond_export_sym(sym, sec, enabled) \
	152	__cond_export_sym_##enabled(sym, sec)
	153	#define __cond_export_sym_1(sym, sec) ___EXPORT_SYMBOL(sym, sec)
	154	#define __cond_export_sym_0(sym, sec) /* nothing */
	155
8651ec01 MM	156	#define __EXPORT_SYMBOL_NS(sym, sec, ns) \
	157	__ksym_marker(sym); \
	158	__cond_export_ns_sym(sym, sec, ns, __is_defined(__KSYM_##sym))
	159	#define __cond_export_ns_sym(sym, sec, ns, conf) \
	160	___cond_export_ns_sym(sym, sec, ns, conf)
	161	#define ___cond_export_ns_sym(sym, sec, ns, enabled) \
	162	__cond_export_ns_sym_##enabled(sym, sec, ns)
	163	#define __cond_export_ns_sym_1(sym, sec, ns) ___EXPORT_SYMBOL_NS(sym, sec, ns)
	164	#define __cond_export_ns_sym_0(sym, sec, ns) /* nothing */
	165
f2355416	166	#else
f2355416	167
e0703556 LT	168	#define __EXPORT_SYMBOL_NS(sym,sec,ns) ___EXPORT_SYMBOL_NS(sym,sec,ns)
e0703556 LT	169	#define __EXPORT_SYMBOL(sym,sec) ___EXPORT_SYMBOL(sym,sec)
f5016932	170
69a94abb	171	#endif /* CONFIG_MODULES */
f5016932	172
8e2adc6a MM	173	#ifdef DEFAULT_SYMBOL_NAMESPACE
	174	#undef __EXPORT_SYMBOL
	175	#define __EXPORT_SYMBOL(sym, sec) \
	176	__EXPORT_SYMBOL_NS(sym, sec, DEFAULT_SYMBOL_NAMESPACE)
	177	#endif
	178
69a94abb MY	179	#define EXPORT_SYMBOL(sym) __EXPORT_SYMBOL(sym, "")
	180	#define EXPORT_SYMBOL_GPL(sym) __EXPORT_SYMBOL(sym, "_gpl")
	181	#define EXPORT_SYMBOL_GPL_FUTURE(sym) __EXPORT_SYMBOL(sym, "_gpl_future")
e0703556 LT	182	#define EXPORT_SYMBOL_NS(sym, ns) __EXPORT_SYMBOL_NS(sym, "", ns)
e0703556 LT	183	#define EXPORT_SYMBOL_NS_GPL(sym, ns) __EXPORT_SYMBOL_NS(sym, "_gpl", ns)
f5016932 PG	184
f5016932 PG	185	#ifdef CONFIG_UNUSED_SYMBOLS
69a94abb MY	186	#define EXPORT_UNUSED_SYMBOL(sym) __EXPORT_SYMBOL(sym, "_unused")
69a94abb MY	187	#define EXPORT_UNUSED_SYMBOL_GPL(sym) __EXPORT_SYMBOL(sym, "_unused_gpl")
f5016932 PG	188	#else
	189	#define EXPORT_UNUSED_SYMBOL(sym)
	190	#define EXPORT_UNUSED_SYMBOL_GPL(sym)
	191	#endif
	192
b92021b0	193	#endif /* !__ASSEMBLY__ */
f5016932 PG	194
f5016932 PG	195	#endif /* _LINUX_EXPORT_H */