Merge remote-tracking branch 'omap_dss2/for-next'
[deliverable/linux.git] / include / linux / export.h
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 /* 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
17 #else
18 #define __VMLINUX_SYMBOL(x) x
19 #define __VMLINUX_SYMBOL_STR(x) #x
20 #endif
21
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)
25
26 #ifndef __ASSEMBLY__
27 struct kernel_symbol
28 {
29 unsigned long value;
30 const char *name;
31 };
32
33 #ifdef MODULE
34 extern struct module __this_module;
35 #define THIS_MODULE (&__this_module)
36 #else
37 #define THIS_MODULE ((struct module *)0)
38 #endif
39
40 #ifdef CONFIG_MODULES
41
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 #define __CRC_SYMBOL(sym, sec) \
47 extern __visible void *__crc_##sym __attribute__((weak)); \
48 static const unsigned long __kcrctab_##sym \
49 __used \
50 __attribute__((section("___kcrctab" sec "+" #sym), used)) \
51 = (unsigned long) &__crc_##sym;
52 #else
53 #define __CRC_SYMBOL(sym, sec)
54 #endif
55
56 /* For every exported symbol, place a struct in the __ksymtab section */
57 #define ___EXPORT_SYMBOL(sym, sec) \
58 extern typeof(sym) sym; \
59 __CRC_SYMBOL(sym, sec) \
60 static const char __kstrtab_##sym[] \
61 __attribute__((section("__ksymtab_strings"), aligned(1))) \
62 = VMLINUX_SYMBOL_STR(sym); \
63 static const struct kernel_symbol __ksymtab_##sym \
64 __used \
65 __attribute__((section("___ksymtab" sec "+" #sym), used)) \
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, __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 */
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