1 #ifndef _LINUX_EXPORT_H 2 #define _LINUX_EXPORT_H 3 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 * 9 * Try not to add #includes here. It slows compilation and makes kernel 10 * hackers place grumpy comments in header files. 11 */ 12 13 /* Some toolchains use a `_' prefix for all user symbols. */ 14 #ifdef CONFIG_HAVE_UNDERSCORE_SYMBOL_PREFIX 15 #define __VMLINUX_SYMBOL(x) _##x 16 #define __VMLINUX_SYMBOL_STR(x) "_" #x 17 #else 18 #define __VMLINUX_SYMBOL(x) x 19 #define __VMLINUX_SYMBOL_STR(x) #x 20 #endif 21 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__ 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 42 #if defined(__KERNEL__) && !defined(__GENKSYMS__) 43 #ifdef CONFIG_MODVERSIONS 44 /* Mark the CRC weak since genksyms apparently decides not to 45 * generate a checksums for some symbols */ 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)) \ 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 */ 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)) \ 66 = { (unsigned long)&sym, __kstrtab_##sym } 67 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) 80 81 #include <generated/autoksyms.h> 82 83 #define __EXPORT_SYMBOL(sym, sec) \ 84 __cond_export_sym(sym, sec, __is_defined(__KSYM_##sym)) 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 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 */ 124 #endif /* !__ASSEMBLY__ */ 125 126 #endif /* _LINUX_EXPORT_H */ 127