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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 | ||
ce2b617c JY |
85 | /* |
86 | * For every exported symbol, do the following: | |
87 | * | |
88 | * - If applicable, place a CRC entry in the __kcrctab section. | |
89 | * - Put the name of the symbol and namespace (empty string "" for none) in | |
90 | * __ksymtab_strings. | |
91 | * - Place a struct kernel_symbol entry in the __ksymtab section. | |
92 | * | |
93 | * note on .section use: we specify progbits since usage of the "M" (SHF_MERGE) | |
94 | * section flag requires it. Use '%progbits' instead of '@progbits' since the | |
95 | * former apparently works on all arches according to the binutils source. | |
96 | */ | |
97 | #define ___EXPORT_SYMBOL(sym, sec, ns) \ | |
98 | extern typeof(sym) sym; \ | |
99 | extern const char __kstrtab_##sym[]; \ | |
100 | extern const char __kstrtabns_##sym[]; \ | |
101 | __CRC_SYMBOL(sym, sec); \ | |
102 | asm(" .section \"__ksymtab_strings\",\"aMS\",%progbits,1 \n" \ | |
103 | "__kstrtab_" #sym ": \n" \ | |
104 | " .asciz \"" #sym "\" \n" \ | |
105 | "__kstrtabns_" #sym ": \n" \ | |
106 | " .asciz \"" ns "\" \n" \ | |
107 | " .previous \n"); \ | |
7290d580 | 108 | __KSYMTAB_ENTRY(sym, sec) |
f5016932 | 109 | |
69a94abb MY |
110 | #endif |
111 | ||
112 | #if !defined(CONFIG_MODULES) || defined(__DISABLE_EXPORTS) | |
f922c4ab AB |
113 | |
114 | /* | |
115 | * Allow symbol exports to be disabled completely so that C code may | |
116 | * be reused in other execution contexts such as the UEFI stub or the | |
117 | * decompressor. | |
118 | */ | |
c3a6cf19 | 119 | #define __EXPORT_SYMBOL(sym, sec, ns) |
f922c4ab | 120 | |
bbda5ec6 MY |
121 | #elif defined(CONFIG_TRIM_UNUSED_KSYMS) |
122 | ||
123 | #include <generated/autoksyms.h> | |
c1a95fda NP |
124 | |
125 | /* | |
126 | * For fine grained build dependencies, we want to tell the build system | |
127 | * about each possible exported symbol even if they're not actually exported. | |
bbda5ec6 MY |
128 | * We use a symbol pattern __ksym_marker_<symbol> that the build system filters |
129 | * from the $(NM) output (see scripts/gen_ksymdeps.sh). These symbols are | |
130 | * discarded in the final link stage. | |
c1a95fda | 131 | */ |
bbda5ec6 | 132 | #define __ksym_marker(sym) \ |
33def849 | 133 | static int __ksym_marker_##sym[0] __section(".discard.ksym") __used |
f2355416 | 134 | |
c3a6cf19 | 135 | #define __EXPORT_SYMBOL(sym, sec, ns) \ |
8651ec01 | 136 | __ksym_marker(sym); \ |
c3a6cf19 MY |
137 | __cond_export_sym(sym, sec, ns, __is_defined(__KSYM_##sym)) |
138 | #define __cond_export_sym(sym, sec, ns, conf) \ | |
139 | ___cond_export_sym(sym, sec, ns, conf) | |
140 | #define ___cond_export_sym(sym, sec, ns, enabled) \ | |
141 | __cond_export_sym_##enabled(sym, sec, ns) | |
142 | #define __cond_export_sym_1(sym, sec, ns) ___EXPORT_SYMBOL(sym, sec, ns) | |
e1327a12 QP |
143 | |
144 | #ifdef __GENKSYMS__ | |
145 | #define __cond_export_sym_0(sym, sec, ns) __GENKSYMS_EXPORT_SYMBOL(sym) | |
146 | #else | |
c3a6cf19 | 147 | #define __cond_export_sym_0(sym, sec, ns) /* nothing */ |
e1327a12 | 148 | #endif |
8651ec01 | 149 | |
f2355416 | 150 | #else |
f2355416 | 151 | |
c3a6cf19 | 152 | #define __EXPORT_SYMBOL(sym, sec, ns) ___EXPORT_SYMBOL(sym, sec, ns) |
f5016932 | 153 | |
69a94abb | 154 | #endif /* CONFIG_MODULES */ |
f5016932 | 155 | |
8e2adc6a | 156 | #ifdef DEFAULT_SYMBOL_NAMESPACE |
c3a6cf19 MY |
157 | #include <linux/stringify.h> |
158 | #define _EXPORT_SYMBOL(sym, sec) __EXPORT_SYMBOL(sym, sec, __stringify(DEFAULT_SYMBOL_NAMESPACE)) | |
159 | #else | |
160 | #define _EXPORT_SYMBOL(sym, sec) __EXPORT_SYMBOL(sym, sec, "") | |
8e2adc6a MM |
161 | #endif |
162 | ||
c3a6cf19 MY |
163 | #define EXPORT_SYMBOL(sym) _EXPORT_SYMBOL(sym, "") |
164 | #define EXPORT_SYMBOL_GPL(sym) _EXPORT_SYMBOL(sym, "_gpl") | |
c3a6cf19 MY |
165 | #define EXPORT_SYMBOL_NS(sym, ns) __EXPORT_SYMBOL(sym, "", #ns) |
166 | #define EXPORT_SYMBOL_NS_GPL(sym, ns) __EXPORT_SYMBOL(sym, "_gpl", #ns) | |
f5016932 | 167 | |
b92021b0 | 168 | #endif /* !__ASSEMBLY__ */ |
f5016932 PG |
169 | |
170 | #endif /* _LINUX_EXPORT_H */ |