xref: /linux/include/linux/export.h (revision e91c37f1)
1 /* SPDX-License-Identifier: GPL-2.0-only */
2 #ifndef _LINUX_EXPORT_H
3 #define _LINUX_EXPORT_H
4 
5 #include <linux/compiler.h>
6 #include <linux/linkage.h>
7 #include <linux/stringify.h>
8 
9 /*
10  * This comment block is used by fixdep. Please do not remove.
11  *
12  * When CONFIG_MODVERSIONS is changed from n to y, all source files having
13  * EXPORT_SYMBOL variants must be re-compiled because genksyms is run as a
14  * side effect of the *.o build rule.
15  */
16 
17 #ifdef CONFIG_64BIT
18 #define __EXPORT_SYMBOL_REF(sym)			\
19 	.balign 8				ASM_NL	\
20 	.quad sym
21 #else
22 #define __EXPORT_SYMBOL_REF(sym)			\
23 	.balign 4				ASM_NL	\
24 	.long sym
25 #endif
26 
27 #define ___EXPORT_SYMBOL(sym, license, ns)		\
28 	.section ".export_symbol","a"		ASM_NL	\
29 	__export_symbol_##sym:			ASM_NL	\
30 		.asciz license			ASM_NL	\
31 		.asciz ns			ASM_NL	\
32 		__EXPORT_SYMBOL_REF(sym)	ASM_NL	\
33 	.previous
34 
35 #if defined(__DISABLE_EXPORTS)
36 
37 /*
38  * Allow symbol exports to be disabled completely so that C code may
39  * be reused in other execution contexts such as the UEFI stub or the
40  * decompressor.
41  */
42 #define __EXPORT_SYMBOL(sym, license, ns)
43 
44 #elif defined(__GENKSYMS__)
45 
46 #define __EXPORT_SYMBOL(sym, license, ns)	__GENKSYMS_EXPORT_SYMBOL(sym)
47 
48 #elif defined(__ASSEMBLY__)
49 
50 #define __EXPORT_SYMBOL(sym, license, ns) \
51 	___EXPORT_SYMBOL(sym, license, ns)
52 
53 #else
54 
55 #define __EXPORT_SYMBOL(sym, license, ns)			\
56 	extern typeof(sym) sym;					\
57 	__ADDRESSABLE(sym)					\
58 	asm(__stringify(___EXPORT_SYMBOL(sym, license, ns)))
59 
60 #endif
61 
62 #ifdef DEFAULT_SYMBOL_NAMESPACE
63 #define _EXPORT_SYMBOL(sym, license)	__EXPORT_SYMBOL(sym, license, __stringify(DEFAULT_SYMBOL_NAMESPACE))
64 #else
65 #define _EXPORT_SYMBOL(sym, license)	__EXPORT_SYMBOL(sym, license, "")
66 #endif
67 
68 #define EXPORT_SYMBOL(sym)		_EXPORT_SYMBOL(sym, "")
69 #define EXPORT_SYMBOL_GPL(sym)		_EXPORT_SYMBOL(sym, "GPL")
70 #define EXPORT_SYMBOL_NS(sym, ns)	__EXPORT_SYMBOL(sym, "", __stringify(ns))
71 #define EXPORT_SYMBOL_NS_GPL(sym, ns)	__EXPORT_SYMBOL(sym, "GPL", __stringify(ns))
72 
73 #endif /* _LINUX_EXPORT_H */
74