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- /* SPDX-License-Identifier: GPL-2.0-only */
- #ifndef _LINUX_EXPORT_H
- #define _LINUX_EXPORT_H
- #include <linux/stringify.h>
- /*
- * Export symbols from the kernel to modules. Forked from module.h
- * to reduce the amount of pointless cruft we feed to gcc when only
- * exporting a simple symbol or two.
- *
- * Try not to add #includes here. It slows compilation and makes kernel
- * hackers place grumpy comments in header files.
- */
- /*
- * This comment block is used by fixdep. Please do not remove.
- *
- * When CONFIG_MODVERSIONS is changed from n to y, all source files having
- * EXPORT_SYMBOL variants must be re-compiled because genksyms is run as a
- * side effect of the *.o build rule.
- */
- #ifndef __ASSEMBLY__
- #ifdef MODULE
- extern struct module __this_module;
- #define THIS_MODULE (&__this_module)
- #else
- #define THIS_MODULE ((struct module *)0)
- #endif
- #ifdef CONFIG_HAVE_ARCH_PREL32_RELOCATIONS
- #include <linux/compiler.h>
- /*
- * Emit the ksymtab entry as a pair of relative references: this reduces
- * the size by half on 64-bit architectures, and eliminates the need for
- * absolute relocations that require runtime processing on relocatable
- * kernels.
- */
- #define __KSYMTAB_ENTRY(sym, sec) \
- __ADDRESSABLE(sym) \
- asm(" .section \"___ksymtab" sec "+" #sym "\", \"a\" \n" \
- " .balign 4 \n" \
- "__ksymtab_" #sym ": \n" \
- " .long " #sym "- . \n" \
- " .long __kstrtab_" #sym "- . \n" \
- " .long __kstrtabns_" #sym "- . \n" \
- " .previous \n")
- struct kernel_symbol {
- int value_offset;
- int name_offset;
- int namespace_offset;
- };
- #else
- #define __KSYMTAB_ENTRY(sym, sec) \
- static const struct kernel_symbol __ksymtab_##sym \
- __attribute__((section("___ksymtab" sec "+" #sym), used)) \
- __aligned(sizeof(void *)) \
- = { (unsigned long)&sym, __kstrtab_##sym, __kstrtabns_##sym }
- struct kernel_symbol {
- unsigned long value;
- const char *name;
- const char *namespace;
- };
- #endif
- #ifdef __GENKSYMS__
- #define ___EXPORT_SYMBOL(sym, sec, ns) __GENKSYMS_EXPORT_SYMBOL(sym)
- #else
- /*
- * For every exported symbol, do the following:
- *
- * - Put the name of the symbol and namespace (empty string "" for none) in
- * __ksymtab_strings.
- * - Place a struct kernel_symbol entry in the __ksymtab section.
- *
- * note on .section use: we specify progbits since usage of the "M" (SHF_MERGE)
- * section flag requires it. Use '%progbits' instead of '@progbits' since the
- * former apparently works on all arches according to the binutils source.
- */
- #define ___EXPORT_SYMBOL(sym, sec, ns) \
- extern typeof(sym) sym; \
- extern const char __kstrtab_##sym[]; \
- extern const char __kstrtabns_##sym[]; \
- asm(" .section \"__ksymtab_strings\",\"aMS\",%progbits,1 \n" \
- "__kstrtab_" #sym ": \n" \
- " .asciz \"" #sym "\" \n" \
- "__kstrtabns_" #sym ": \n" \
- " .asciz \"" ns "\" \n" \
- " .previous \n"); \
- __KSYMTAB_ENTRY(sym, sec)
- #endif
- #if !defined(CONFIG_MODULES) || defined(__DISABLE_EXPORTS)
- /*
- * Allow symbol exports to be disabled completely so that C code may
- * be reused in other execution contexts such as the UEFI stub or the
- * decompressor.
- */
- #define __EXPORT_SYMBOL(sym, sec, ns)
- #elif defined(CONFIG_TRIM_UNUSED_KSYMS) && !defined(MODULE)
- #include <generated/autoksyms.h>
- /*
- * For fine grained build dependencies, we want to tell the build system
- * about each possible exported symbol even if they're not actually exported.
- * We use a symbol pattern __ksym_marker_<symbol> that the build system filters
- * from the $(NM) output (see scripts/gen_ksymdeps.sh). These symbols are
- * discarded in the final link stage.
- */
- #define __ksym_marker(sym) \
- static int __ksym_marker_##sym[0] __section(".discard.ksym") __used
- #define __EXPORT_SYMBOL(sym, sec, ns) \
- __ksym_marker(sym); \
- __cond_export_sym(sym, sec, ns, __is_defined(__KSYM_##sym))
- #define __cond_export_sym(sym, sec, ns, conf) \
- ___cond_export_sym(sym, sec, ns, conf)
- #define ___cond_export_sym(sym, sec, ns, enabled) \
- __cond_export_sym_##enabled(sym, sec, ns)
- #define __cond_export_sym_1(sym, sec, ns) ___EXPORT_SYMBOL(sym, sec, ns)
- #ifdef __GENKSYMS__
- #define __cond_export_sym_0(sym, sec, ns) __GENKSYMS_EXPORT_SYMBOL(sym)
- #else
- #define __cond_export_sym_0(sym, sec, ns) /* nothing */
- #endif
- #else
- #define __EXPORT_SYMBOL(sym, sec, ns) ___EXPORT_SYMBOL(sym, sec, ns)
- #endif /* CONFIG_MODULES */
- #ifdef DEFAULT_SYMBOL_NAMESPACE
- #define _EXPORT_SYMBOL(sym, sec) __EXPORT_SYMBOL(sym, sec, __stringify(DEFAULT_SYMBOL_NAMESPACE))
- #else
- #define _EXPORT_SYMBOL(sym, sec) __EXPORT_SYMBOL(sym, sec, "")
- #endif
- #define EXPORT_SYMBOL(sym) _EXPORT_SYMBOL(sym, "")
- #if IS_ENABLED(CONFIG_SEC_KUNIT) && IS_ENABLED(CONFIG_KUNIT)
- #define EXPORT_SYMBOL_KUNIT(sym) _EXPORT_SYMBOL(sym, "")
- #else
- #define EXPORT_SYMBOL_KUNIT(sym) /* nothing */
- #endif
- #define EXPORT_SYMBOL_GPL(sym) _EXPORT_SYMBOL(sym, "_gpl")
- #define EXPORT_SYMBOL_NS(sym, ns) __EXPORT_SYMBOL(sym, "", __stringify(ns))
- #define EXPORT_SYMBOL_NS_GPL(sym, ns) __EXPORT_SYMBOL(sym, "_gpl", __stringify(ns))
- #endif /* !__ASSEMBLY__ */
- #endif /* _LINUX_EXPORT_H */
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