include/linux/export.h

   1 /* SPDX-License-Identifier: GPL-2.0-only */
   2 #ifndef _LINUX_EXPORT_H
   3 #define _LINUX_EXPORT_H
   4
   5 #include <linux/compiler.h>
   6 #include <linux/linkage.h>
   7 #include <linux/stringify.h>
   8
   9 /*
  10  * This comment block is used by fixdep. Please do not remove.
  11  *
  12  * When CONFIG_MODVERSIONS is changed from n to y, all source files having
  13  * EXPORT_SYMBOL variants must be re-compiled because genksyms is run as a
  14  * side effect of the *.o build rule.
  15  */
  16
  17 #ifdef CONFIG_64BIT
  18 #define __EXPORT_SYMBOL_REF(sym)                        \
  19         .balign 8                               ASM_NL  \
  20         .quad sym
  21 #else
  22 #define __EXPORT_SYMBOL_REF(sym)                        \
  23         .balign 4                               ASM_NL  \
  24         .long sym
  25 #endif
  26
  27 #define ___EXPORT_SYMBOL(sym, license, ns)              \
  28         .section ".export_symbol","a"           ASM_NL  \
  29         __export_symbol_##sym:                  ASM_NL  \
  30                 .asciz license                  ASM_NL  \
  31                 .asciz ns                       ASM_NL  \
  32                 __EXPORT_SYMBOL_REF(sym)        ASM_NL  \
  33         .previous
  34
  35 #if defined(__DISABLE_EXPORTS)
  36
  37 /*
  38  * Allow symbol exports to be disabled completely so that C code may
  39  * be reused in other execution contexts such as the UEFI stub or the
  40  * decompressor.
  41  */
  42 #define __EXPORT_SYMBOL(sym, license, ns)
  43
  44 #elif defined(__GENKSYMS__)
  45
  46 #define __EXPORT_SYMBOL(sym, license, ns)       __GENKSYMS_EXPORT_SYMBOL(sym)
  47
  48 #elif defined(__ASSEMBLY__)
  49
  50 #define __EXPORT_SYMBOL(sym, license, ns) \
  51         ___EXPORT_SYMBOL(sym, license, ns)
  52
  53 #else
  54
  55 #define __EXPORT_SYMBOL(sym, license, ns)                       \
  56         extern typeof(sym) sym;                                 \
  57         __ADDRESSABLE(sym)                                      \
  58         asm(__stringify(___EXPORT_SYMBOL(sym, license, ns)))
  59
  60 #endif
  61
  62 #ifdef DEFAULT_SYMBOL_NAMESPACE
  63 #define _EXPORT_SYMBOL(sym, license)    __EXPORT_SYMBOL(sym, license, __stringify(DEFAULT_SYMBOL_NAMESPACE))
  64 #else
  65 #define _EXPORT_SYMBOL(sym, license)    __EXPORT_SYMBOL(sym, license, "")
  66 #endif
  67
  68 #define EXPORT_SYMBOL(sym)              _EXPORT_SYMBOL(sym, "")
  69 #define EXPORT_SYMBOL_GPL(sym)          _EXPORT_SYMBOL(sym, "GPL")
  70 #define EXPORT_SYMBOL_NS(sym, ns)       __EXPORT_SYMBOL(sym, "", __stringify(ns))
  71 #define EXPORT_SYMBOL_NS_GPL(sym, ns)   __EXPORT_SYMBOL(sym, "GPL", __stringify(ns))
  72
  73 #endif /* _LINUX_EXPORT_H */