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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 | |
d143b9db GKH |
5 | #include <linux/stringify.h> |
6 | ||
f5016932 PG |
7 | /* |
8 | * Export symbols from the kernel to modules. Forked from module.h | |
9 | * to reduce the amount of pointless cruft we feed to gcc when only | |
10 | * exporting a simple symbol or two. | |
11 | * | |
b92021b0 RR |
12 | * Try not to add #includes here. It slows compilation and makes kernel |
13 | * hackers place grumpy comments in header files. | |
f5016932 PG |
14 | */ |
15 | ||
7b453719 MY |
16 | /* |
17 | * This comment block is used by fixdep. Please do not remove. | |
18 | * | |
19 | * When CONFIG_MODVERSIONS is changed from n to y, all source files having | |
20 | * EXPORT_SYMBOL variants must be re-compiled because genksyms is run as a | |
21 | * side effect of the *.o build rule. | |
22 | */ | |
23 | ||
b92021b0 | 24 | #ifndef __ASSEMBLY__ |
f5016932 PG |
25 | #ifdef MODULE |
26 | extern struct module __this_module; | |
27 | #define THIS_MODULE (&__this_module) | |
28 | #else | |
29 | #define THIS_MODULE ((struct module *)0) | |
30 | #endif | |
31 | ||
7290d580 AB |
32 | #ifdef CONFIG_HAVE_ARCH_PREL32_RELOCATIONS |
33 | #include <linux/compiler.h> | |
34 | /* | |
35 | * Emit the ksymtab entry as a pair of relative references: this reduces | |
36 | * the size by half on 64-bit architectures, and eliminates the need for | |
37 | * absolute relocations that require runtime processing on relocatable | |
38 | * kernels. | |
39 | */ | |
c3a6cf19 | 40 | #define __KSYMTAB_ENTRY(sym, sec) \ |
8651ec01 MM |
41 | __ADDRESSABLE(sym) \ |
42 | asm(" .section \"___ksymtab" sec "+" #sym "\", \"a\" \n" \ | |
43 | " .balign 4 \n" \ | |
69923208 | 44 | "__ksymtab_" #sym ": \n" \ |
8651ec01 MM |
45 | " .long " #sym "- . \n" \ |
46 | " .long __kstrtab_" #sym "- . \n" \ | |
fa6643cd | 47 | " .long __kstrtabns_" #sym "- . \n" \ |
8651ec01 MM |
48 | " .previous \n") |
49 | ||
7290d580 AB |
50 | struct kernel_symbol { |
51 | int value_offset; | |
52 | int name_offset; | |
8651ec01 | 53 | int namespace_offset; |
7290d580 AB |
54 | }; |
55 | #else | |
56 | #define __KSYMTAB_ENTRY(sym, sec) \ | |
57 | static const struct kernel_symbol __ksymtab_##sym \ | |
58 | __attribute__((section("___ksymtab" sec "+" #sym), used)) \ | |
ed13fc33 | 59 | __aligned(sizeof(void *)) \ |
c3a6cf19 | 60 | = { (unsigned long)&sym, __kstrtab_##sym, __kstrtabns_##sym } |
7290d580 AB |
61 | |
62 | struct kernel_symbol { | |
63 | unsigned long value; | |
64 | const char *name; | |
8651ec01 | 65 | const char *namespace; |
7290d580 AB |
66 | }; |
67 | #endif | |
68 | ||
69a94abb MY |
69 | #ifdef __GENKSYMS__ |
70 | ||
c3a6cf19 | 71 | #define ___EXPORT_SYMBOL(sym, sec, ns) __GENKSYMS_EXPORT_SYMBOL(sym) |
69a94abb MY |
72 | |
73 | #else | |
74 | ||
ce2b617c JY |
75 | /* |
76 | * For every exported symbol, do the following: | |
77 | * | |
ce2b617c JY |
78 | * - Put the name of the symbol and namespace (empty string "" for none) in |
79 | * __ksymtab_strings. | |
80 | * - Place a struct kernel_symbol entry in the __ksymtab section. | |
81 | * | |
82 | * note on .section use: we specify progbits since usage of the "M" (SHF_MERGE) | |
83 | * section flag requires it. Use '%progbits' instead of '@progbits' since the | |
84 | * former apparently works on all arches according to the binutils source. | |
85 | */ | |
86 | #define ___EXPORT_SYMBOL(sym, sec, ns) \ | |
87 | extern typeof(sym) sym; \ | |
88 | extern const char __kstrtab_##sym[]; \ | |
89 | extern const char __kstrtabns_##sym[]; \ | |
ce2b617c JY |
90 | asm(" .section \"__ksymtab_strings\",\"aMS\",%progbits,1 \n" \ |
91 | "__kstrtab_" #sym ": \n" \ | |
92 | " .asciz \"" #sym "\" \n" \ | |
93 | "__kstrtabns_" #sym ": \n" \ | |
94 | " .asciz \"" ns "\" \n" \ | |
95 | " .previous \n"); \ | |
7290d580 | 96 | __KSYMTAB_ENTRY(sym, sec) |
f5016932 | 97 | |
69a94abb MY |
98 | #endif |
99 | ||
100 | #if !defined(CONFIG_MODULES) || defined(__DISABLE_EXPORTS) | |
f922c4ab AB |
101 | |
102 | /* | |
103 | * Allow symbol exports to be disabled completely so that C code may | |
104 | * be reused in other execution contexts such as the UEFI stub or the | |
105 | * decompressor. | |
106 | */ | |
c3a6cf19 | 107 | #define __EXPORT_SYMBOL(sym, sec, ns) |
f922c4ab | 108 | |
bbda5ec6 MY |
109 | #elif defined(CONFIG_TRIM_UNUSED_KSYMS) |
110 | ||
111 | #include <generated/autoksyms.h> | |
c1a95fda NP |
112 | |
113 | /* | |
114 | * For fine grained build dependencies, we want to tell the build system | |
115 | * about each possible exported symbol even if they're not actually exported. | |
bbda5ec6 MY |
116 | * We use a symbol pattern __ksym_marker_<symbol> that the build system filters |
117 | * from the $(NM) output (see scripts/gen_ksymdeps.sh). These symbols are | |
118 | * discarded in the final link stage. | |
c1a95fda | 119 | */ |
bbda5ec6 | 120 | #define __ksym_marker(sym) \ |
33def849 | 121 | static int __ksym_marker_##sym[0] __section(".discard.ksym") __used |
f2355416 | 122 | |
c3a6cf19 | 123 | #define __EXPORT_SYMBOL(sym, sec, ns) \ |
8651ec01 | 124 | __ksym_marker(sym); \ |
c3a6cf19 MY |
125 | __cond_export_sym(sym, sec, ns, __is_defined(__KSYM_##sym)) |
126 | #define __cond_export_sym(sym, sec, ns, conf) \ | |
127 | ___cond_export_sym(sym, sec, ns, conf) | |
128 | #define ___cond_export_sym(sym, sec, ns, enabled) \ | |
129 | __cond_export_sym_##enabled(sym, sec, ns) | |
130 | #define __cond_export_sym_1(sym, sec, ns) ___EXPORT_SYMBOL(sym, sec, ns) | |
e1327a12 QP |
131 | |
132 | #ifdef __GENKSYMS__ | |
133 | #define __cond_export_sym_0(sym, sec, ns) __GENKSYMS_EXPORT_SYMBOL(sym) | |
134 | #else | |
c3a6cf19 | 135 | #define __cond_export_sym_0(sym, sec, ns) /* nothing */ |
e1327a12 | 136 | #endif |
8651ec01 | 137 | |
f2355416 | 138 | #else |
f2355416 | 139 | |
c3a6cf19 | 140 | #define __EXPORT_SYMBOL(sym, sec, ns) ___EXPORT_SYMBOL(sym, sec, ns) |
f5016932 | 141 | |
69a94abb | 142 | #endif /* CONFIG_MODULES */ |
f5016932 | 143 | |
8e2adc6a | 144 | #ifdef DEFAULT_SYMBOL_NAMESPACE |
c3a6cf19 MY |
145 | #define _EXPORT_SYMBOL(sym, sec) __EXPORT_SYMBOL(sym, sec, __stringify(DEFAULT_SYMBOL_NAMESPACE)) |
146 | #else | |
147 | #define _EXPORT_SYMBOL(sym, sec) __EXPORT_SYMBOL(sym, sec, "") | |
8e2adc6a MM |
148 | #endif |
149 | ||
c3a6cf19 MY |
150 | #define EXPORT_SYMBOL(sym) _EXPORT_SYMBOL(sym, "") |
151 | #define EXPORT_SYMBOL_GPL(sym) _EXPORT_SYMBOL(sym, "_gpl") | |
d143b9db GKH |
152 | #define EXPORT_SYMBOL_NS(sym, ns) __EXPORT_SYMBOL(sym, "", __stringify(ns)) |
153 | #define EXPORT_SYMBOL_NS_GPL(sym, ns) __EXPORT_SYMBOL(sym, "_gpl", __stringify(ns)) | |
f5016932 | 154 | |
b92021b0 | 155 | #endif /* !__ASSEMBLY__ */ |
f5016932 PG |
156 | |
157 | #endif /* _LINUX_EXPORT_H */ |