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 * Export symbols from the kernel to modules. Forked from module.h 11 * to reduce the amount of pointless cruft we feed to gcc when only 12 * exporting a simple symbol or two. 13 * 14 * Try not to add #includes here. It slows compilation and makes kernel 15 * hackers place grumpy comments in header files. 16 */ 17 18 /* 19 * This comment block is used by fixdep. Please do not remove. 20 * 21 * When CONFIG_MODVERSIONS is changed from n to y, all source files having 22 * EXPORT_SYMBOL variants must be re-compiled because genksyms is run as a 23 * side effect of the *.o build rule. 24 */ 25 26 #ifndef __ASSEMBLY__ 27 #ifdef MODULE 28 extern struct module __this_module; 29 #define THIS_MODULE (&__this_module) 30 #else 31 #define THIS_MODULE ((struct module *)0) 32 #endif 33 #endif /* __ASSEMBLY__ */ 34 35 #ifdef CONFIG_64BIT 36 #define __EXPORT_SYMBOL_REF(sym) \ 37 .balign 8 ASM_NL \ 38 .quad sym 39 #else 40 #define __EXPORT_SYMBOL_REF(sym) \ 41 .balign 4 ASM_NL \ 42 .long sym 43 #endif 44 45 #define ____EXPORT_SYMBOL(sym, license, ns) \ 46 .section ".export_symbol","a" ASM_NL \ 47 __export_symbol_##sym: ASM_NL \ 48 .asciz license ASM_NL \ 49 .asciz ns ASM_NL \ 50 __EXPORT_SYMBOL_REF(sym) ASM_NL \ 51 .previous 52 53 #ifdef __GENKSYMS__ 54 55 #define ___EXPORT_SYMBOL(sym, sec, ns) __GENKSYMS_EXPORT_SYMBOL(sym) 56 57 #elif defined(__ASSEMBLY__) 58 59 #define ___EXPORT_SYMBOL(sym, license, ns) \ 60 ____EXPORT_SYMBOL(sym, license, ns) 61 62 #else 63 64 #define ___EXPORT_SYMBOL(sym, license, ns) \ 65 extern typeof(sym) sym; \ 66 __ADDRESSABLE(sym) \ 67 asm(__stringify(____EXPORT_SYMBOL(sym, license, ns))) 68 69 #endif 70 71 #if !defined(CONFIG_MODULES) || defined(__DISABLE_EXPORTS) 72 73 /* 74 * Allow symbol exports to be disabled completely so that C code may 75 * be reused in other execution contexts such as the UEFI stub or the 76 * decompressor. 77 */ 78 #define __EXPORT_SYMBOL(sym, sec, ns) 79 80 #elif defined(CONFIG_TRIM_UNUSED_KSYMS) 81 82 #include <generated/autoksyms.h> 83 84 /* 85 * For fine grained build dependencies, we want to tell the build system 86 * about each possible exported symbol even if they're not actually exported. 87 * We use a symbol pattern __ksym_marker_<symbol> that the build system filters 88 * from the $(NM) output (see scripts/gen_ksymdeps.sh). These symbols are 89 * discarded in the final link stage. 90 */ 91 92 #ifdef __ASSEMBLY__ 93 94 #define __ksym_marker(sym) \ 95 .section ".discard.ksym","a" ; \ 96 __ksym_marker_##sym: ; \ 97 .previous 98 99 #else 100 101 #define __ksym_marker(sym) \ 102 static int __ksym_marker_##sym[0] __section(".discard.ksym") __used 103 104 #endif 105 106 #define __EXPORT_SYMBOL(sym, sec, ns) \ 107 __ksym_marker(sym); \ 108 __cond_export_sym(sym, sec, ns, __is_defined(__KSYM_##sym)) 109 #define __cond_export_sym(sym, sec, ns, conf) \ 110 ___cond_export_sym(sym, sec, ns, conf) 111 #define ___cond_export_sym(sym, sec, ns, enabled) \ 112 __cond_export_sym_##enabled(sym, sec, ns) 113 #define __cond_export_sym_1(sym, sec, ns) ___EXPORT_SYMBOL(sym, sec, ns) 114 115 #ifdef __GENKSYMS__ 116 #define __cond_export_sym_0(sym, sec, ns) __GENKSYMS_EXPORT_SYMBOL(sym) 117 #else 118 #define __cond_export_sym_0(sym, sec, ns) /* nothing */ 119 #endif 120 121 #else 122 123 #define __EXPORT_SYMBOL(sym, sec, ns) ___EXPORT_SYMBOL(sym, sec, ns) 124 125 #endif /* CONFIG_MODULES */ 126 127 #ifdef DEFAULT_SYMBOL_NAMESPACE 128 #define _EXPORT_SYMBOL(sym, sec) __EXPORT_SYMBOL(sym, sec, __stringify(DEFAULT_SYMBOL_NAMESPACE)) 129 #else 130 #define _EXPORT_SYMBOL(sym, sec) __EXPORT_SYMBOL(sym, sec, "") 131 #endif 132 133 #define EXPORT_SYMBOL(sym) _EXPORT_SYMBOL(sym, "") 134 #define EXPORT_SYMBOL_GPL(sym) _EXPORT_SYMBOL(sym, "GPL") 135 #define EXPORT_SYMBOL_NS(sym, ns) __EXPORT_SYMBOL(sym, "", __stringify(ns)) 136 #define EXPORT_SYMBOL_NS_GPL(sym, ns) __EXPORT_SYMBOL(sym, "GPL", __stringify(ns)) 137 138 #endif /* _LINUX_EXPORT_H */ 139