1 #ifndef _LINUX_EXPORT_H
2 #define _LINUX_EXPORT_H
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.
9 * Try not to add #includes here. It slows compilation and makes kernel
10 * hackers place grumpy comments in header files.
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
18 #define __VMLINUX_SYMBOL(x) x
19 #define __VMLINUX_SYMBOL_STR(x) #x
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)
34 extern struct module __this_module;
35 #define THIS_MODULE (&__this_module)
37 #define THIS_MODULE ((struct module *)0)
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 #if defined(CONFIG_MODULE_REL_CRCS)
47 #define __CRC_SYMBOL(sym, sec) \
48 asm(" .section \"___kcrctab" sec "+" #sym "\", \"a\" \n" \
49 " .weak " VMLINUX_SYMBOL_STR(__crc_##sym) " \n" \
50 " .long " VMLINUX_SYMBOL_STR(__crc_##sym) " - . \n" \
52 #elif !defined(CONFIG_64BIT)
53 #define __CRC_SYMBOL(sym, sec) \
54 extern __visible void *__crc_##sym __attribute__((weak)); \
55 static const unsigned long __kcrctab_##sym \
57 __attribute__((section("___kcrctab" sec "+" #sym), used)) \
58 = (unsigned long) &__crc_##sym;
60 #define __CRC_SYMBOL(sym, sec) \
61 asm(" .section \"___kcrctab" sec "+" #sym "\", \"a\" \n" \
62 " .weak " VMLINUX_SYMBOL_STR(__crc_##sym) " \n" \
63 " .long " VMLINUX_SYMBOL_STR(__crc_##sym) " \n" \
67 #define __CRC_SYMBOL(sym, sec)
70 /* For every exported symbol, place a struct in the __ksymtab section */
71 #define ___EXPORT_SYMBOL(sym, sec) \
72 extern typeof(sym) sym; \
73 __CRC_SYMBOL(sym, sec) \
74 static const char __kstrtab_##sym[] \
75 __attribute__((section("__ksymtab_strings"), aligned(1))) \
76 = VMLINUX_SYMBOL_STR(sym); \
77 static const struct kernel_symbol __ksymtab_##sym \
79 __attribute__((section("___ksymtab" sec "+" #sym), used)) \
80 = { (unsigned long)&sym, __kstrtab_##sym }
82 #if defined(__KSYM_DEPS__)
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 string pattern that is unlikely to be valid code that the build
88 * system filters out from the preprocessor output (see ksym_dep_filter
89 * in scripts/Kbuild.include).
91 #define __EXPORT_SYMBOL(sym, sec) === __KSYM_##sym ===
93 #elif defined(CONFIG_TRIM_UNUSED_KSYMS)
95 #include <generated/autoksyms.h>
97 #define __EXPORT_SYMBOL(sym, sec) \
98 __cond_export_sym(sym, sec, __is_defined(__KSYM_##sym))
99 #define __cond_export_sym(sym, sec, conf) \
100 ___cond_export_sym(sym, sec, conf)
101 #define ___cond_export_sym(sym, sec, enabled) \
102 __cond_export_sym_##enabled(sym, sec)
103 #define __cond_export_sym_1(sym, sec) ___EXPORT_SYMBOL(sym, sec)
104 #define __cond_export_sym_0(sym, sec) /* nothing */
107 #define __EXPORT_SYMBOL ___EXPORT_SYMBOL
110 #define EXPORT_SYMBOL(sym) \
111 __EXPORT_SYMBOL(sym, "")
113 #define EXPORT_SYMBOL_GPL(sym) \
114 __EXPORT_SYMBOL(sym, "_gpl")
116 #define EXPORT_SYMBOL_GPL_FUTURE(sym) \
117 __EXPORT_SYMBOL(sym, "_gpl_future")
119 #ifdef CONFIG_UNUSED_SYMBOLS
120 #define EXPORT_UNUSED_SYMBOL(sym) __EXPORT_SYMBOL(sym, "_unused")
121 #define EXPORT_UNUSED_SYMBOL_GPL(sym) __EXPORT_SYMBOL(sym, "_unused_gpl")
123 #define EXPORT_UNUSED_SYMBOL(sym)
124 #define EXPORT_UNUSED_SYMBOL_GPL(sym)
127 #endif /* __GENKSYMS__ */
129 #else /* !CONFIG_MODULES... */
131 #define EXPORT_SYMBOL(sym)
132 #define EXPORT_SYMBOL_GPL(sym)
133 #define EXPORT_SYMBOL_GPL_FUTURE(sym)
134 #define EXPORT_UNUSED_SYMBOL(sym)
135 #define EXPORT_UNUSED_SYMBOL_GPL(sym)
137 #endif /* CONFIG_MODULES */
138 #endif /* !__ASSEMBLY__ */
140 #endif /* _LINUX_EXPORT_H */