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 #define __VMLINUX_SYMBOL(x) x 14 #define __VMLINUX_SYMBOL_STR(x) #x 15 16 /* Indirect, so macros are expanded before pasting. */ 17 #define VMLINUX_SYMBOL(x) __VMLINUX_SYMBOL(x) 18 #define VMLINUX_SYMBOL_STR(x) __VMLINUX_SYMBOL_STR(x) 19 20 #ifndef __ASSEMBLY__ 21 struct kernel_symbol 22 { 23 unsigned long value; 24 const char *name; 25 }; 26 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 34 #ifdef CONFIG_MODULES 35 36 #if defined(__KERNEL__) && !defined(__GENKSYMS__) 37 #ifdef CONFIG_MODVERSIONS 38 /* Mark the CRC weak since genksyms apparently decides not to 39 * generate a checksums for some symbols */ 40 #if defined(CONFIG_MODULE_REL_CRCS) 41 #define __CRC_SYMBOL(sym, sec) \ 42 asm(" .section \"___kcrctab" sec "+" #sym "\", \"a\" \n" \ 43 " .weak __crc_" #sym " \n" \ 44 " .long __crc_" #sym " - . \n" \ 45 " .previous \n"); 46 #else 47 #define __CRC_SYMBOL(sym, sec) \ 48 asm(" .section \"___kcrctab" sec "+" #sym "\", \"a\" \n" \ 49 " .weak __crc_" #sym " \n" \ 50 " .long __crc_" #sym " \n" \ 51 " .previous \n"); 52 #endif 53 #else 54 #define __CRC_SYMBOL(sym, sec) 55 #endif 56 57 /* For every exported symbol, place a struct in the __ksymtab section */ 58 #define ___EXPORT_SYMBOL(sym, sec) \ 59 extern typeof(sym) sym; \ 60 __CRC_SYMBOL(sym, sec) \ 61 static const char __kstrtab_##sym[] \ 62 __attribute__((section("__ksymtab_strings"), aligned(1))) \ 63 = #sym; \ 64 static const struct kernel_symbol __ksymtab_##sym \ 65 __used \ 66 __attribute__((section("___ksymtab" sec "+" #sym), used)) \ 67 = { (unsigned long)&sym, __kstrtab_##sym } 68 69 #if defined(__KSYM_DEPS__) 70 71 /* 72 * For fine grained build dependencies, we want to tell the build system 73 * about each possible exported symbol even if they're not actually exported. 74 * We use a string pattern that is unlikely to be valid code that the build 75 * system filters out from the preprocessor output (see ksym_dep_filter 76 * in scripts/Kbuild.include). 77 */ 78 #define __EXPORT_SYMBOL(sym, sec) === __KSYM_##sym === 79 80 #elif defined(CONFIG_TRIM_UNUSED_KSYMS) 81 82 #include <generated/autoksyms.h> 83 84 #define __EXPORT_SYMBOL(sym, sec) \ 85 __cond_export_sym(sym, sec, __is_defined(__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