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__
21struct kernel_symbol
22{
23 unsigned long value;
24 const char *name;
25};
26
27#ifdef MODULE
28extern 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