Linux Kernel  3.7.1
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export.h
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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  * If you feel the need to add #include <linux/foo.h> to this file
9  * then you are doing something wrong and should go away silently.
10  */
11 
12 /* Some toolchains use a `_' prefix for all user symbols. */
13 #ifdef CONFIG_SYMBOL_PREFIX
14 #define MODULE_SYMBOL_PREFIX CONFIG_SYMBOL_PREFIX
15 #else
16 #define MODULE_SYMBOL_PREFIX ""
17 #endif
18 
20 {
21  unsigned long value;
22  const char *name;
23 };
24 
25 #ifdef MODULE
26 extern struct module __this_module;
27 #define THIS_MODULE (&__this_module)
28 #else
29 #define THIS_MODULE ((struct module *)0)
30 #endif
31 
32 #ifdef CONFIG_MODULES
33 
34 #ifndef __GENKSYMS__
35 #ifdef CONFIG_MODVERSIONS
36 /* Mark the CRC weak since genksyms apparently decides not to
37  * generate a checksums for some symbols */
38 #define __CRC_SYMBOL(sym, sec) \
39  extern void *__crc_##sym __attribute__((weak)); \
40  static const unsigned long __kcrctab_##sym \
41  __used \
42  __attribute__((section("___kcrctab" sec "+" #sym), unused)) \
43  = (unsigned long) &__crc_##sym;
44 #else
45 #define __CRC_SYMBOL(sym, sec)
46 #endif
47 
48 /* For every exported symbol, place a struct in the __ksymtab section */
49 #define __EXPORT_SYMBOL(sym, sec) \
50  extern typeof(sym) sym; \
51  __CRC_SYMBOL(sym, sec) \
52  static const char __kstrtab_##sym[] \
53  __attribute__((section("__ksymtab_strings"), aligned(1))) \
54  = MODULE_SYMBOL_PREFIX #sym; \
55  static const struct kernel_symbol __ksymtab_##sym \
56  __used \
57  __attribute__((section("___ksymtab" sec "+" #sym), unused)) \
58  = { (unsigned long)&sym, __kstrtab_##sym }
59 
60 #define EXPORT_SYMBOL(sym) \
61  __EXPORT_SYMBOL(sym, "")
62 
63 #define EXPORT_SYMBOL_GPL(sym) \
64  __EXPORT_SYMBOL(sym, "_gpl")
65 
66 #define EXPORT_SYMBOL_GPL_FUTURE(sym) \
67  __EXPORT_SYMBOL(sym, "_gpl_future")
68 
69 #ifdef CONFIG_UNUSED_SYMBOLS
70 #define EXPORT_UNUSED_SYMBOL(sym) __EXPORT_SYMBOL(sym, "_unused")
71 #define EXPORT_UNUSED_SYMBOL_GPL(sym) __EXPORT_SYMBOL(sym, "_unused_gpl")
72 #else
73 #define EXPORT_UNUSED_SYMBOL(sym)
74 #define EXPORT_UNUSED_SYMBOL_GPL(sym)
75 #endif
76 
77 #endif /* __GENKSYMS__ */
78 
79 #else /* !CONFIG_MODULES... */
80 
81 #define EXPORT_SYMBOL(sym)
82 #define EXPORT_SYMBOL_GPL(sym)
83 #define EXPORT_SYMBOL_GPL_FUTURE(sym)
84 #define EXPORT_UNUSED_SYMBOL(sym)
85 #define EXPORT_UNUSED_SYMBOL_GPL(sym)
86 
87 #endif /* CONFIG_MODULES */
88 
89 #endif /* _LINUX_EXPORT_H */