196 lines
6.2 KiB
C
196 lines
6.2 KiB
C
#ifndef _LINUX_EXPORT_H
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#define _LINUX_EXPORT_H
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/*
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* Export symbols from the kernel to modules. Forked from module.h
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* to reduce the amount of pointless cruft we feed to gcc when only
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* exporting a simple symbol or two.
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*
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* Try not to add #includes here. It slows compilation and makes kernel
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* hackers place grumpy comments in header files.
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*/
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#ifndef __ASSEMBLY__
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#ifdef MODULE
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extern struct module __this_module;
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#define THIS_MODULE (&__this_module)
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#else
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#define THIS_MODULE ((struct module *)0)
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#endif
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#ifdef CONFIG_MODVERSIONS
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/* Mark the CRC weak since genksyms apparently decides not to
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* generate a checksums for some symbols */
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#if defined(CONFIG_MODULE_REL_CRCS)
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#define __CRC_SYMBOL(sym, sec) \
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asm(" .section \"___kcrctab" sec "+" #sym "\", \"a\" \n" \
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" .weak __crc_" #sym " \n" \
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" .long __crc_" #sym " - . \n" \
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" .previous \n")
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#else
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#define __CRC_SYMBOL(sym, sec) \
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asm(" .section \"___kcrctab" sec "+" #sym "\", \"a\" \n" \
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" .weak __crc_" #sym " \n" \
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" .long __crc_" #sym " \n" \
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" .previous \n")
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#endif
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#else
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#define __CRC_SYMBOL(sym, sec)
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#endif
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#ifdef CONFIG_HAVE_ARCH_PREL32_RELOCATIONS
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#include <linux/compiler.h>
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/*
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* Emit the ksymtab entry as a pair of relative references: this reduces
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* the size by half on 64-bit architectures, and eliminates the need for
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* absolute relocations that require runtime processing on relocatable
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* kernels.
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*/
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#define __KSYMTAB_ENTRY_NS(sym, sec) \
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__ADDRESSABLE(sym) \
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asm(" .section \"___ksymtab" sec "+" #sym "\", \"a\" \n" \
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" .balign 4 \n" \
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"__ksymtab_" #sym ": \n" \
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" .long " #sym "- . \n" \
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" .long __kstrtab_" #sym "- . \n" \
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" .long __kstrtabns_" #sym "- . \n" \
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" .previous \n")
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#define __KSYMTAB_ENTRY(sym, sec) \
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__ADDRESSABLE(sym) \
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asm(" .section \"___ksymtab" sec "+" #sym "\", \"a\" \n" \
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" .balign 4 \n" \
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"__ksymtab_" #sym ": \n" \
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" .long " #sym "- . \n" \
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" .long __kstrtab_" #sym "- . \n" \
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" .long 0 \n" \
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" .previous \n")
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struct kernel_symbol {
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int value_offset;
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int name_offset;
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int namespace_offset;
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};
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#else
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#define __KSYMTAB_ENTRY_NS(sym, sec) \
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static const struct kernel_symbol __ksymtab_##sym \
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__attribute__((section("___ksymtab" sec "+" #sym), used)) \
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__aligned(sizeof(void *)) \
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= { (unsigned long)&sym, __kstrtab_##sym, __kstrtabns_##sym }
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#define __KSYMTAB_ENTRY(sym, sec) \
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static const struct kernel_symbol __ksymtab_##sym \
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__attribute__((section("___ksymtab" sec "+" #sym), used)) \
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__aligned(sizeof(void *)) \
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= { (unsigned long)&sym, __kstrtab_##sym, NULL }
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struct kernel_symbol {
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unsigned long value;
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const char *name;
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const char *namespace;
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};
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#endif
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#ifdef __GENKSYMS__
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#define ___EXPORT_SYMBOL(sym,sec) __GENKSYMS_EXPORT_SYMBOL(sym)
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#define ___EXPORT_SYMBOL_NS(sym,sec,ns) __GENKSYMS_EXPORT_SYMBOL(sym)
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#else
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#define ___export_symbol_common(sym, sec) \
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extern typeof(sym) sym; \
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__CRC_SYMBOL(sym, sec); \
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static const char __kstrtab_##sym[] \
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__attribute__((section("__ksymtab_strings"), used, aligned(1))) \
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= #sym \
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/* For every exported symbol, place a struct in the __ksymtab section */
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#define ___EXPORT_SYMBOL_NS(sym, sec, ns) \
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___export_symbol_common(sym, sec); \
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static const char __kstrtabns_##sym[] \
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__attribute__((section("__ksymtab_strings"), used, aligned(1))) \
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= #ns; \
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__KSYMTAB_ENTRY_NS(sym, sec)
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#define ___EXPORT_SYMBOL(sym, sec) \
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___export_symbol_common(sym, sec); \
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__KSYMTAB_ENTRY(sym, sec)
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#endif
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#if !defined(CONFIG_MODULES) || defined(__DISABLE_EXPORTS)
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/*
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* Allow symbol exports to be disabled completely so that C code may
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* be reused in other execution contexts such as the UEFI stub or the
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* decompressor.
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*/
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#define __EXPORT_SYMBOL_NS(sym, sec, ns)
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#define __EXPORT_SYMBOL(sym, sec)
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#elif defined(CONFIG_TRIM_UNUSED_KSYMS)
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#include <generated/autoksyms.h>
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/*
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* For fine grained build dependencies, we want to tell the build system
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* about each possible exported symbol even if they're not actually exported.
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* We use a symbol pattern __ksym_marker_<symbol> that the build system filters
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* from the $(NM) output (see scripts/gen_ksymdeps.sh). These symbols are
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* discarded in the final link stage.
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*/
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#define __ksym_marker(sym) \
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static int __ksym_marker_##sym[0] __section(".discard.ksym") __used
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#define __EXPORT_SYMBOL(sym, sec) \
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__ksym_marker(sym); \
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__cond_export_sym(sym, sec, __is_defined(__KSYM_##sym))
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#define __cond_export_sym(sym, sec, conf) \
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___cond_export_sym(sym, sec, conf)
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#define ___cond_export_sym(sym, sec, enabled) \
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__cond_export_sym_##enabled(sym, sec)
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#define __cond_export_sym_1(sym, sec) ___EXPORT_SYMBOL(sym, sec)
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#define __cond_export_sym_0(sym, sec) /* nothing */
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#define __EXPORT_SYMBOL_NS(sym, sec, ns) \
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__ksym_marker(sym); \
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__cond_export_ns_sym(sym, sec, ns, __is_defined(__KSYM_##sym))
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#define __cond_export_ns_sym(sym, sec, ns, conf) \
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___cond_export_ns_sym(sym, sec, ns, conf)
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#define ___cond_export_ns_sym(sym, sec, ns, enabled) \
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__cond_export_ns_sym_##enabled(sym, sec, ns)
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#define __cond_export_ns_sym_1(sym, sec, ns) ___EXPORT_SYMBOL_NS(sym, sec, ns)
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#define __cond_export_ns_sym_0(sym, sec, ns) /* nothing */
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#else
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#define __EXPORT_SYMBOL_NS(sym,sec,ns) ___EXPORT_SYMBOL_NS(sym,sec,ns)
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#define __EXPORT_SYMBOL(sym,sec) ___EXPORT_SYMBOL(sym,sec)
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#endif /* CONFIG_MODULES */
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#ifdef DEFAULT_SYMBOL_NAMESPACE
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#undef __EXPORT_SYMBOL
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#define __EXPORT_SYMBOL(sym, sec) \
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__EXPORT_SYMBOL_NS(sym, sec, DEFAULT_SYMBOL_NAMESPACE)
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#endif
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#define EXPORT_SYMBOL(sym) __EXPORT_SYMBOL(sym, "")
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#define EXPORT_SYMBOL_GPL(sym) __EXPORT_SYMBOL(sym, "_gpl")
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#define EXPORT_SYMBOL_GPL_FUTURE(sym) __EXPORT_SYMBOL(sym, "_gpl_future")
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#define EXPORT_SYMBOL_NS(sym, ns) __EXPORT_SYMBOL_NS(sym, "", ns)
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#define EXPORT_SYMBOL_NS_GPL(sym, ns) __EXPORT_SYMBOL_NS(sym, "_gpl", ns)
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#ifdef CONFIG_UNUSED_SYMBOLS
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#define EXPORT_UNUSED_SYMBOL(sym) __EXPORT_SYMBOL(sym, "_unused")
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#define EXPORT_UNUSED_SYMBOL_GPL(sym) __EXPORT_SYMBOL(sym, "_unused_gpl")
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#else
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#define EXPORT_UNUSED_SYMBOL(sym)
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#define EXPORT_UNUSED_SYMBOL_GPL(sym)
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#endif
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#endif /* !__ASSEMBLY__ */
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#endif /* _LINUX_EXPORT_H */
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