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bf49d9dd | 1 | /* SPDX-License-Identifier: GPL-2.0-only */ |
f5016932 PG |
2 | #ifndef _LINUX_EXPORT_H |
3 | #define _LINUX_EXPORT_H | |
b67067f1 | 4 | |
f5016932 PG |
5 | /* |
6 | * Export symbols from the kernel to modules. Forked from module.h | |
7 | * to reduce the amount of pointless cruft we feed to gcc when only | |
8 | * exporting a simple symbol or two. | |
9 | * | |
b92021b0 RR |
10 | * Try not to add #includes here. It slows compilation and makes kernel |
11 | * hackers place grumpy comments in header files. | |
f5016932 PG |
12 | */ |
13 | ||
b92021b0 | 14 | #ifndef __ASSEMBLY__ |
f5016932 PG |
15 | #ifdef MODULE |
16 | extern struct module __this_module; | |
17 | #define THIS_MODULE (&__this_module) | |
18 | #else | |
19 | #define THIS_MODULE ((struct module *)0) | |
20 | #endif | |
21 | ||
f5016932 PG |
22 | #ifdef CONFIG_MODVERSIONS |
23 | /* Mark the CRC weak since genksyms apparently decides not to | |
24 | * generate a checksums for some symbols */ | |
71810db2 AB |
25 | #if defined(CONFIG_MODULE_REL_CRCS) |
26 | #define __CRC_SYMBOL(sym, sec) \ | |
27 | asm(" .section \"___kcrctab" sec "+" #sym "\", \"a\" \n" \ | |
94e58e0a MY |
28 | " .weak __crc_" #sym " \n" \ |
29 | " .long __crc_" #sym " - . \n" \ | |
8651ec01 | 30 | " .previous \n") |
f5016932 | 31 | #else |
71810db2 AB |
32 | #define __CRC_SYMBOL(sym, sec) \ |
33 | asm(" .section \"___kcrctab" sec "+" #sym "\", \"a\" \n" \ | |
94e58e0a MY |
34 | " .weak __crc_" #sym " \n" \ |
35 | " .long __crc_" #sym " \n" \ | |
8651ec01 | 36 | " .previous \n") |
71810db2 AB |
37 | #endif |
38 | #else | |
f5016932 PG |
39 | #define __CRC_SYMBOL(sym, sec) |
40 | #endif | |
41 | ||
7290d580 AB |
42 | #ifdef CONFIG_HAVE_ARCH_PREL32_RELOCATIONS |
43 | #include <linux/compiler.h> | |
44 | /* | |
45 | * Emit the ksymtab entry as a pair of relative references: this reduces | |
46 | * the size by half on 64-bit architectures, and eliminates the need for | |
47 | * absolute relocations that require runtime processing on relocatable | |
48 | * kernels. | |
49 | */ | |
c3a6cf19 | 50 | #define __KSYMTAB_ENTRY(sym, sec) \ |
8651ec01 MM |
51 | __ADDRESSABLE(sym) \ |
52 | asm(" .section \"___ksymtab" sec "+" #sym "\", \"a\" \n" \ | |
53 | " .balign 4 \n" \ | |
69923208 | 54 | "__ksymtab_" #sym ": \n" \ |
8651ec01 MM |
55 | " .long " #sym "- . \n" \ |
56 | " .long __kstrtab_" #sym "- . \n" \ | |
fa6643cd | 57 | " .long __kstrtabns_" #sym "- . \n" \ |
8651ec01 MM |
58 | " .previous \n") |
59 | ||
7290d580 AB |
60 | struct kernel_symbol { |
61 | int value_offset; | |
62 | int name_offset; | |
8651ec01 | 63 | int namespace_offset; |
7290d580 AB |
64 | }; |
65 | #else | |
66 | #define __KSYMTAB_ENTRY(sym, sec) \ | |
67 | static const struct kernel_symbol __ksymtab_##sym \ | |
68 | __attribute__((section("___ksymtab" sec "+" #sym), used)) \ | |
ed13fc33 | 69 | __aligned(sizeof(void *)) \ |
c3a6cf19 | 70 | = { (unsigned long)&sym, __kstrtab_##sym, __kstrtabns_##sym } |
7290d580 AB |
71 | |
72 | struct kernel_symbol { | |
73 | unsigned long value; | |
74 | const char *name; | |
8651ec01 | 75 | const char *namespace; |
7290d580 AB |
76 | }; |
77 | #endif | |
78 | ||
69a94abb MY |
79 | #ifdef __GENKSYMS__ |
80 | ||
c3a6cf19 | 81 | #define ___EXPORT_SYMBOL(sym, sec, ns) __GENKSYMS_EXPORT_SYMBOL(sym) |
69a94abb MY |
82 | |
83 | #else | |
84 | ||
c3a6cf19 MY |
85 | /* For every exported symbol, place a struct in the __ksymtab section */ |
86 | #define ___EXPORT_SYMBOL(sym, sec, ns) \ | |
b67067f1 | 87 | extern typeof(sym) sym; \ |
8651ec01 | 88 | __CRC_SYMBOL(sym, sec); \ |
b67067f1 | 89 | static const char __kstrtab_##sym[] \ |
7290d580 | 90 | __attribute__((section("__ksymtab_strings"), used, aligned(1))) \ |
c3a6cf19 | 91 | = #sym; \ |
fa6643cd | 92 | static const char __kstrtabns_##sym[] \ |
8651ec01 | 93 | __attribute__((section("__ksymtab_strings"), used, aligned(1))) \ |
c3a6cf19 | 94 | = ns; \ |
7290d580 | 95 | __KSYMTAB_ENTRY(sym, sec) |
f5016932 | 96 | |
69a94abb MY |
97 | #endif |
98 | ||
99 | #if !defined(CONFIG_MODULES) || defined(__DISABLE_EXPORTS) | |
f922c4ab AB |
100 | |
101 | /* | |
102 | * Allow symbol exports to be disabled completely so that C code may | |
103 | * be reused in other execution contexts such as the UEFI stub or the | |
104 | * decompressor. | |
105 | */ | |
c3a6cf19 | 106 | #define __EXPORT_SYMBOL(sym, sec, ns) |
f922c4ab | 107 | |
bbda5ec6 MY |
108 | #elif defined(CONFIG_TRIM_UNUSED_KSYMS) |
109 | ||
110 | #include <generated/autoksyms.h> | |
c1a95fda NP |
111 | |
112 | /* | |
113 | * For fine grained build dependencies, we want to tell the build system | |
114 | * about each possible exported symbol even if they're not actually exported. | |
bbda5ec6 MY |
115 | * We use a symbol pattern __ksym_marker_<symbol> that the build system filters |
116 | * from the $(NM) output (see scripts/gen_ksymdeps.sh). These symbols are | |
117 | * discarded in the final link stage. | |
c1a95fda | 118 | */ |
bbda5ec6 MY |
119 | #define __ksym_marker(sym) \ |
120 | static int __ksym_marker_##sym[0] __section(".discard.ksym") __used | |
f2355416 | 121 | |
c3a6cf19 | 122 | #define __EXPORT_SYMBOL(sym, sec, ns) \ |
8651ec01 | 123 | __ksym_marker(sym); \ |
c3a6cf19 MY |
124 | __cond_export_sym(sym, sec, ns, __is_defined(__KSYM_##sym)) |
125 | #define __cond_export_sym(sym, sec, ns, conf) \ | |
126 | ___cond_export_sym(sym, sec, ns, conf) | |
127 | #define ___cond_export_sym(sym, sec, ns, enabled) \ | |
128 | __cond_export_sym_##enabled(sym, sec, ns) | |
129 | #define __cond_export_sym_1(sym, sec, ns) ___EXPORT_SYMBOL(sym, sec, ns) | |
130 | #define __cond_export_sym_0(sym, sec, ns) /* nothing */ | |
8651ec01 | 131 | |
f2355416 | 132 | #else |
f2355416 | 133 | |
c3a6cf19 | 134 | #define __EXPORT_SYMBOL(sym, sec, ns) ___EXPORT_SYMBOL(sym, sec, ns) |
f5016932 | 135 | |
69a94abb | 136 | #endif /* CONFIG_MODULES */ |
f5016932 | 137 | |
8e2adc6a | 138 | #ifdef DEFAULT_SYMBOL_NAMESPACE |
c3a6cf19 MY |
139 | #include <linux/stringify.h> |
140 | #define _EXPORT_SYMBOL(sym, sec) __EXPORT_SYMBOL(sym, sec, __stringify(DEFAULT_SYMBOL_NAMESPACE)) | |
141 | #else | |
142 | #define _EXPORT_SYMBOL(sym, sec) __EXPORT_SYMBOL(sym, sec, "") | |
8e2adc6a MM |
143 | #endif |
144 | ||
c3a6cf19 MY |
145 | #define EXPORT_SYMBOL(sym) _EXPORT_SYMBOL(sym, "") |
146 | #define EXPORT_SYMBOL_GPL(sym) _EXPORT_SYMBOL(sym, "_gpl") | |
147 | #define EXPORT_SYMBOL_GPL_FUTURE(sym) _EXPORT_SYMBOL(sym, "_gpl_future") | |
148 | #define EXPORT_SYMBOL_NS(sym, ns) __EXPORT_SYMBOL(sym, "", #ns) | |
149 | #define EXPORT_SYMBOL_NS_GPL(sym, ns) __EXPORT_SYMBOL(sym, "_gpl", #ns) | |
f5016932 PG |
150 | |
151 | #ifdef CONFIG_UNUSED_SYMBOLS | |
c3a6cf19 MY |
152 | #define EXPORT_UNUSED_SYMBOL(sym) _EXPORT_SYMBOL(sym, "_unused") |
153 | #define EXPORT_UNUSED_SYMBOL_GPL(sym) _EXPORT_SYMBOL(sym, "_unused_gpl") | |
f5016932 PG |
154 | #else |
155 | #define EXPORT_UNUSED_SYMBOL(sym) | |
156 | #define EXPORT_UNUSED_SYMBOL_GPL(sym) | |
157 | #endif | |
158 | ||
b92021b0 | 159 | #endif /* !__ASSEMBLY__ */ |
f5016932 PG |
160 | |
161 | #endif /* _LINUX_EXPORT_H */ |