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 #ifndef __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 #define EXPORT_SYMBOL(sym) \ 69 __EXPORT_SYMBOL(sym, "") 70 71 #define EXPORT_SYMBOL_GPL(sym) \ 72 __EXPORT_SYMBOL(sym, "_gpl") 73 74 #define EXPORT_SYMBOL_GPL_FUTURE(sym) \ 75 __EXPORT_SYMBOL(sym, "_gpl_future") 76 77 #ifdef CONFIG_UNUSED_SYMBOLS 78 #define EXPORT_UNUSED_SYMBOL(sym) __EXPORT_SYMBOL(sym, "_unused") 79 #define EXPORT_UNUSED_SYMBOL_GPL(sym) __EXPORT_SYMBOL(sym, "_unused_gpl") 80 #else 81 #define EXPORT_UNUSED_SYMBOL(sym) 82 #define EXPORT_UNUSED_SYMBOL_GPL(sym) 83 #endif 84 85 #endif /* __GENKSYMS__ */ 86 87 #else /* !CONFIG_MODULES... */ 88 89 #define EXPORT_SYMBOL(sym) 90 #define EXPORT_SYMBOL_GPL(sym) 91 #define EXPORT_SYMBOL_GPL_FUTURE(sym) 92 #define EXPORT_UNUSED_SYMBOL(sym) 93 #define EXPORT_UNUSED_SYMBOL_GPL(sym) 94 95 #endif /* CONFIG_MODULES */ 96 #endif /* !__ASSEMBLY__ */ 97 98 #endif /* _LINUX_EXPORT_H */ 99