1 #ifndef _LINUX_EXPORT_H 2 #define _LINUX_EXPORT_H 3 /* 4 * Export symbols from the kernel to modules. Forked from module.h 5 * to reduce the amount of pointless cruft we feed to gcc when only 6 * exporting a simple symbol or two. 7 * 8 * Try not to add #includes here. It slows compilation and makes kernel 9 * hackers place grumpy comments in header files. 10 */ 11 12 /* Some toolchains use a `_' prefix for all user symbols. */ 13 #ifdef CONFIG_HAVE_UNDERSCORE_SYMBOL_PREFIX 14 #define __VMLINUX_SYMBOL(x) _##x 15 #define __VMLINUX_SYMBOL_STR(x) "_" #x 16 #else 17 #define __VMLINUX_SYMBOL(x) x 18 #define __VMLINUX_SYMBOL_STR(x) #x 19 #endif 20 21 /* Indirect, so macros are expanded before pasting. */ 22 #define VMLINUX_SYMBOL(x) __VMLINUX_SYMBOL(x) 23 #define VMLINUX_SYMBOL_STR(x) __VMLINUX_SYMBOL_STR(x) 24 25 #ifndef __ASSEMBLY__ 26 struct kernel_symbol 27 { 28 unsigned long value; 29 const char *name; 30 }; 31 32 #ifdef MODULE 33 extern struct module __this_module; 34 #define THIS_MODULE (&__this_module) 35 #else 36 #define THIS_MODULE ((struct module *)0) 37 #endif 38 39 #ifdef CONFIG_MODULES 40 41 #if defined(__KERNEL__) && !defined(__GENKSYMS__) 42 #ifdef CONFIG_MODVERSIONS 43 /* Mark the CRC weak since genksyms apparently decides not to 44 * generate a checksums for some symbols */ 45 #define __CRC_SYMBOL(sym, sec) \ 46 extern __visible void *__crc_##sym __attribute__((weak)); \ 47 static const unsigned long __kcrctab_##sym \ 48 __used \ 49 __attribute__((section("___kcrctab" sec "+" #sym), unused)) \ 50 = (unsigned long) &__crc_##sym; 51 #else 52 #define __CRC_SYMBOL(sym, sec) 53 #endif 54 55 /* For every exported symbol, place a struct in the __ksymtab section */ 56 #define ___EXPORT_SYMBOL(sym, sec) \ 57 extern typeof(sym) sym; \ 58 __CRC_SYMBOL(sym, sec) \ 59 static const char __kstrtab_##sym[] \ 60 __attribute__((section("__ksymtab_strings"), aligned(1))) \ 61 = VMLINUX_SYMBOL_STR(sym); \ 62 extern const struct kernel_symbol __ksymtab_##sym; \ 63 __visible const struct kernel_symbol __ksymtab_##sym \ 64 __used \ 65 __attribute__((section("___ksymtab" sec "+" #sym), unused)) \ 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 <linux/kconfig.h> 82 #include <generated/autoksyms.h> 83 84 #define __EXPORT_SYMBOL(sym, sec) \ 85 __cond_export_sym(sym, sec, config_enabled(__KSYM_##sym)) 86 #define __cond_export_sym(sym, sec, conf) \ 87 ___cond_export_sym(sym, sec, conf) 88 #define ___cond_export_sym(sym, sec, enabled) \ 89 __cond_export_sym_##enabled(sym, sec) 90 #define __cond_export_sym_1(sym, sec) ___EXPORT_SYMBOL(sym, sec) 91 #define __cond_export_sym_0(sym, sec) /* nothing */ 92 93 #else 94 #define __EXPORT_SYMBOL ___EXPORT_SYMBOL 95 #endif 96 97 #define EXPORT_SYMBOL(sym) \ 98 __EXPORT_SYMBOL(sym, "") 99 100 #define EXPORT_SYMBOL_GPL(sym) \ 101 __EXPORT_SYMBOL(sym, "_gpl") 102 103 #define EXPORT_SYMBOL_GPL_FUTURE(sym) \ 104 __EXPORT_SYMBOL(sym, "_gpl_future") 105 106 #ifdef CONFIG_UNUSED_SYMBOLS 107 #define EXPORT_UNUSED_SYMBOL(sym) __EXPORT_SYMBOL(sym, "_unused") 108 #define EXPORT_UNUSED_SYMBOL_GPL(sym) __EXPORT_SYMBOL(sym, "_unused_gpl") 109 #else 110 #define EXPORT_UNUSED_SYMBOL(sym) 111 #define EXPORT_UNUSED_SYMBOL_GPL(sym) 112 #endif 113 114 #endif /* __GENKSYMS__ */ 115 116 #else /* !CONFIG_MODULES... */ 117 118 #define EXPORT_SYMBOL(sym) 119 #define EXPORT_SYMBOL_GPL(sym) 120 #define EXPORT_SYMBOL_GPL_FUTURE(sym) 121 #define EXPORT_UNUSED_SYMBOL(sym) 122 #define EXPORT_UNUSED_SYMBOL_GPL(sym) 123 124 #endif /* CONFIG_MODULES */ 125 #endif /* !__ASSEMBLY__ */ 126 127 #endif /* _LINUX_EXPORT_H */ 128