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 /* 28 * LLVM integrated assembler cam merge adjacent string literals (like 29 * C and GNU-as) passed to '.ascii', but not to '.asciz' and chokes on: 30 * 31 * .asciz "MODULE_" "kvm" ; 32 */ 33 #define ___EXPORT_SYMBOL(sym, license, ns...) \ 34 .section ".export_symbol","a" ASM_NL \ 35 __export_symbol_##sym: ASM_NL \ 36 .asciz license ASM_NL \ 37 .ascii ns "\0" ASM_NL \ 38 __EXPORT_SYMBOL_REF(sym) ASM_NL \ 39 .previous 40 41 #if defined(__DISABLE_EXPORTS) 42 43 /* 44 * Allow symbol exports to be disabled completely so that C code may 45 * be reused in other execution contexts such as the UEFI stub or the 46 * decompressor. 47 */ 48 #define __EXPORT_SYMBOL(sym, license, ns) 49 50 #elif defined(__GENKSYMS__) 51 52 #define __EXPORT_SYMBOL(sym, license, ns) __GENKSYMS_EXPORT_SYMBOL(sym) 53 54 #elif defined(__ASSEMBLY__) 55 56 #define __EXPORT_SYMBOL(sym, license, ns) \ 57 ___EXPORT_SYMBOL(sym, license, ns) 58 59 #else 60 61 #ifdef CONFIG_GENDWARFKSYMS 62 /* 63 * With CONFIG_GENDWARFKSYMS, ensure the compiler emits debugging 64 * information for all exported symbols, including those defined in 65 * different TUs, by adding a __gendwarfksyms_ptr_<symbol> pointer 66 * that's discarded during the final link. 67 */ 68 #define __GENDWARFKSYMS_EXPORT(sym) \ 69 static typeof(sym) *__gendwarfksyms_ptr_##sym __used \ 70 __section(".discard.gendwarfksyms") = &sym; 71 #else 72 #define __GENDWARFKSYMS_EXPORT(sym) 73 #endif 74 75 #define __EXPORT_SYMBOL(sym, license, ns) \ 76 extern typeof(sym) sym; \ 77 __ADDRESSABLE(sym) \ 78 __GENDWARFKSYMS_EXPORT(sym) \ 79 asm(__stringify(___EXPORT_SYMBOL(sym, license, ns))) 80 81 #endif 82 83 #ifdef DEFAULT_SYMBOL_NAMESPACE 84 #define _EXPORT_SYMBOL(sym, license) __EXPORT_SYMBOL(sym, license, DEFAULT_SYMBOL_NAMESPACE) 85 #else 86 #define _EXPORT_SYMBOL(sym, license) __EXPORT_SYMBOL(sym, license, "") 87 #endif 88 89 #define EXPORT_SYMBOL(sym) _EXPORT_SYMBOL(sym, "") 90 #define EXPORT_SYMBOL_GPL(sym) _EXPORT_SYMBOL(sym, "GPL") 91 #define EXPORT_SYMBOL_NS(sym, ns) __EXPORT_SYMBOL(sym, "", ns) 92 #define EXPORT_SYMBOL_NS_GPL(sym, ns) __EXPORT_SYMBOL(sym, "GPL", ns) 93 94 #define EXPORT_SYMBOL_GPL_FOR_MODULES(sym, mods) __EXPORT_SYMBOL(sym, "GPL", "module:" mods) 95 96 #endif /* _LINUX_EXPORT_H */ 97