Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
tjh.dev
kernel
os
linux
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__
27struct kernel_symbol
28{
29 unsigned long value;
30 const char *name;
31};
32
33#ifdef MODULE
34extern 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 <generated/autoksyms.h>
82
83#define __EXPORT_SYMBOL(sym, sec) \
84 __cond_export_sym(sym, sec, __is_defined(__KSYM_##sym))
85#define __cond_export_sym(sym, sec, conf) \
86 ___cond_export_sym(sym, sec, conf)
87#define ___cond_export_sym(sym, sec, enabled) \
88 __cond_export_sym_##enabled(sym, sec)
89#define __cond_export_sym_1(sym, sec) ___EXPORT_SYMBOL(sym, sec)
90#define __cond_export_sym_0(sym, sec) /* nothing */
91
92#else
93#define __EXPORT_SYMBOL ___EXPORT_SYMBOL
94#endif
95
96#define EXPORT_SYMBOL(sym) \
97 __EXPORT_SYMBOL(sym, "")
98
99#define EXPORT_SYMBOL_GPL(sym) \
100 __EXPORT_SYMBOL(sym, "_gpl")
101
102#define EXPORT_SYMBOL_GPL_FUTURE(sym) \
103 __EXPORT_SYMBOL(sym, "_gpl_future")
104
105#ifdef CONFIG_UNUSED_SYMBOLS
106#define EXPORT_UNUSED_SYMBOL(sym) __EXPORT_SYMBOL(sym, "_unused")
107#define EXPORT_UNUSED_SYMBOL_GPL(sym) __EXPORT_SYMBOL(sym, "_unused_gpl")
108#else
109#define EXPORT_UNUSED_SYMBOL(sym)
110#define EXPORT_UNUSED_SYMBOL_GPL(sym)
111#endif
112
113#endif /* __GENKSYMS__ */
114
115#else /* !CONFIG_MODULES... */
116
117#define EXPORT_SYMBOL(sym)
118#define EXPORT_SYMBOL_GPL(sym)
119#define EXPORT_SYMBOL_GPL_FUTURE(sym)
120#define EXPORT_UNUSED_SYMBOL(sym)
121#define EXPORT_UNUSED_SYMBOL_GPL(sym)
122
123#endif /* CONFIG_MODULES */
124#endif /* !__ASSEMBLY__ */
125
126#endif /* _LINUX_EXPORT_H */