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#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" \
51 " .previous \n");
52#else
53#define __CRC_SYMBOL(sym, sec) \
54 asm(" .section \"___kcrctab" sec "+" #sym "\", \"a\" \n" \
55 " .weak " VMLINUX_SYMBOL_STR(__crc_##sym) " \n" \
56 " .long " VMLINUX_SYMBOL_STR(__crc_##sym) " \n" \
57 " .previous \n");
58#endif
59#else
60#define __CRC_SYMBOL(sym, sec)
61#endif
62
63/* For every exported symbol, place a struct in the __ksymtab section */
64#define ___EXPORT_SYMBOL(sym, sec) \
65 extern typeof(sym) sym; \
66 __CRC_SYMBOL(sym, sec) \
67 static const char __kstrtab_##sym[] \
68 __attribute__((section("__ksymtab_strings"), aligned(1))) \
69 = VMLINUX_SYMBOL_STR(sym); \
70 static const struct kernel_symbol __ksymtab_##sym \
71 __used \
72 __attribute__((section("___ksymtab" sec "+" #sym), used)) \
73 = { (unsigned long)&sym, __kstrtab_##sym }
74
75#if defined(__KSYM_DEPS__)
76
77/*
78 * For fine grained build dependencies, we want to tell the build system
79 * about each possible exported symbol even if they're not actually exported.
80 * We use a string pattern that is unlikely to be valid code that the build
81 * system filters out from the preprocessor output (see ksym_dep_filter
82 * in scripts/Kbuild.include).
83 */
84#define __EXPORT_SYMBOL(sym, sec) === __KSYM_##sym ===
85
86#elif defined(CONFIG_TRIM_UNUSED_KSYMS)
87
88#include <generated/autoksyms.h>
89
90#define __EXPORT_SYMBOL(sym, sec) \
91 __cond_export_sym(sym, sec, __is_defined(__KSYM_##sym))
92#define __cond_export_sym(sym, sec, conf) \
93 ___cond_export_sym(sym, sec, conf)
94#define ___cond_export_sym(sym, sec, enabled) \
95 __cond_export_sym_##enabled(sym, sec)
96#define __cond_export_sym_1(sym, sec) ___EXPORT_SYMBOL(sym, sec)
97#define __cond_export_sym_0(sym, sec) /* nothing */
98
99#else
100#define __EXPORT_SYMBOL ___EXPORT_SYMBOL
101#endif
102
103#define EXPORT_SYMBOL(sym) \
104 __EXPORT_SYMBOL(sym, "")
105
106#define EXPORT_SYMBOL_GPL(sym) \
107 __EXPORT_SYMBOL(sym, "_gpl")
108
109#define EXPORT_SYMBOL_GPL_FUTURE(sym) \
110 __EXPORT_SYMBOL(sym, "_gpl_future")
111
112#ifdef CONFIG_UNUSED_SYMBOLS
113#define EXPORT_UNUSED_SYMBOL(sym) __EXPORT_SYMBOL(sym, "_unused")
114#define EXPORT_UNUSED_SYMBOL_GPL(sym) __EXPORT_SYMBOL(sym, "_unused_gpl")
115#else
116#define EXPORT_UNUSED_SYMBOL(sym)
117#define EXPORT_UNUSED_SYMBOL_GPL(sym)
118#endif
119
120#endif /* __GENKSYMS__ */
121
122#else /* !CONFIG_MODULES... */
123
124#define EXPORT_SYMBOL(sym)
125#define EXPORT_SYMBOL_GPL(sym)
126#define EXPORT_SYMBOL_GPL_FUTURE(sym)
127#define EXPORT_UNUSED_SYMBOL(sym)
128#define EXPORT_UNUSED_SYMBOL_GPL(sym)
129
130#endif /* CONFIG_MODULES */
131#endif /* !__ASSEMBLY__ */
132
133#endif /* _LINUX_EXPORT_H */