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-rw-r--r--include/linux/export.h177
1 files changed, 60 insertions, 117 deletions
diff --git a/include/linux/export.h b/include/linux/export.h
index fd8711ed9ac4..a686fd0ba406 100644
--- a/include/linux/export.h
+++ b/include/linux/export.h
@@ -1,87 +1,42 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
#ifndef _LINUX_EXPORT_H
#define _LINUX_EXPORT_H
+#include <linux/compiler.h>
+#include <linux/linkage.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.
+ * This comment block is used by fixdep. Please do not remove.
*
- * Try not to add #includes here. It slows compilation and makes kernel
- * hackers place grumpy comments in header files.
+ * 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)
+#ifdef CONFIG_64BIT
+#define __EXPORT_SYMBOL_REF(sym) \
+ .balign 8 ASM_NL \
+ .quad sym
#else
-#define THIS_MODULE ((struct module *)0)
+#define __EXPORT_SYMBOL_REF(sym) \
+ .balign 4 ASM_NL \
+ .long sym
#endif
-#ifdef CONFIG_MODULES
-
-#if defined(__KERNEL__) && !defined(__GENKSYMS__)
-#ifdef CONFIG_MODVERSIONS
-/* Mark the CRC weak since genksyms apparently decides not to
- * generate a checksums for some symbols */
-#if defined(CONFIG_MODULE_REL_CRCS)
-#define __CRC_SYMBOL(sym, sec) \
- asm(" .section \"___kcrctab" sec "+" #sym "\", \"a\" \n" \
- " .weak __crc_" #sym " \n" \
- " .long __crc_" #sym " - . \n" \
- " .previous \n");
-#else
-#define __CRC_SYMBOL(sym, sec) \
- asm(" .section \"___kcrctab" sec "+" #sym "\", \"a\" \n" \
- " .weak __crc_" #sym " \n" \
- " .long __crc_" #sym " \n" \
- " .previous \n");
-#endif
-#else
-#define __CRC_SYMBOL(sym, sec)
-#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.
+ * LLVM integrated assembler cam merge adjacent string literals (like
+ * C and GNU-as) passed to '.ascii', but not to '.asciz' and chokes on:
+ *
+ * .asciz "MODULE_" "kvm" ;
*/
-#define __KSYMTAB_ENTRY(sym, sec) \
- __ADDRESSABLE(sym) \
- asm(" .section \"___ksymtab" sec "+" #sym "\", \"a\" \n" \
- " .balign 8 \n" \
- "__ksymtab_" #sym ": \n" \
- " .long " #sym "- . \n" \
- " .long __kstrtab_" #sym "- . \n" \
- " .previous \n")
-
-struct kernel_symbol {
- int value_offset;
- int name_offset;
-};
-#else
-#define __KSYMTAB_ENTRY(sym, sec) \
- static const struct kernel_symbol __ksymtab_##sym \
- __attribute__((section("___ksymtab" sec "+" #sym), used)) \
- = { (unsigned long)&sym, __kstrtab_##sym }
-
-struct kernel_symbol {
- unsigned long value;
- const char *name;
-};
-#endif
-
-/* For every exported symbol, place a struct in the __ksymtab section */
-#define ___EXPORT_SYMBOL(sym, sec) \
- extern typeof(sym) sym; \
- __CRC_SYMBOL(sym, sec) \
- static const char __kstrtab_##sym[] \
- __attribute__((section("__ksymtab_strings"), used, aligned(1))) \
- = #sym; \
- __KSYMTAB_ENTRY(sym, sec)
+#define ___EXPORT_SYMBOL(sym, license, ns...) \
+ .section ".export_symbol","a" ASM_NL \
+ __export_symbol_##sym: ASM_NL \
+ .asciz license ASM_NL \
+ .ascii ns "\0" ASM_NL \
+ __EXPORT_SYMBOL_REF(sym) ASM_NL \
+ .previous
#if defined(__DISABLE_EXPORTS)
@@ -90,64 +45,52 @@ struct kernel_symbol {
* be reused in other execution contexts such as the UEFI stub or the
* decompressor.
*/
-#define __EXPORT_SYMBOL(sym, sec)
+#define __EXPORT_SYMBOL(sym, license, ns)
+
+#elif defined(__GENKSYMS__)
+
+#define __EXPORT_SYMBOL(sym, license, ns) __GENKSYMS_EXPORT_SYMBOL(sym)
-#elif defined(CONFIG_TRIM_UNUSED_KSYMS)
+#elif defined(__ASSEMBLY__)
-#include <generated/autoksyms.h>
+#define __EXPORT_SYMBOL(sym, license, ns) \
+ ___EXPORT_SYMBOL(sym, license, ns)
+
+#else
+#ifdef CONFIG_GENDWARFKSYMS
/*
- * 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.
+ * With CONFIG_GENDWARFKSYMS, ensure the compiler emits debugging
+ * information for all exported symbols, including those defined in
+ * different TUs, by adding a __gendwarfksyms_ptr_<symbol> pointer
+ * that's discarded during the final link.
*/
-#define __ksym_marker(sym) \
- static int __ksym_marker_##sym[0] __section(".discard.ksym") __used
-
-#define __EXPORT_SYMBOL(sym, sec) \
- __ksym_marker(sym); \
- __cond_export_sym(sym, sec, __is_defined(__KSYM_##sym))
-#define __cond_export_sym(sym, sec, conf) \
- ___cond_export_sym(sym, sec, conf)
-#define ___cond_export_sym(sym, sec, enabled) \
- __cond_export_sym_##enabled(sym, sec)
-#define __cond_export_sym_1(sym, sec) ___EXPORT_SYMBOL(sym, sec)
-#define __cond_export_sym_0(sym, sec) /* nothing */
-
+#define __GENDWARFKSYMS_EXPORT(sym) \
+ static typeof(sym) *__gendwarfksyms_ptr_##sym __used \
+ __section(".discard.gendwarfksyms") = &sym;
#else
-#define __EXPORT_SYMBOL ___EXPORT_SYMBOL
+#define __GENDWARFKSYMS_EXPORT(sym)
#endif
-#define EXPORT_SYMBOL(sym) \
- __EXPORT_SYMBOL(sym, "")
-
-#define EXPORT_SYMBOL_GPL(sym) \
- __EXPORT_SYMBOL(sym, "_gpl")
+#define __EXPORT_SYMBOL(sym, license, ns) \
+ extern typeof(sym) sym; \
+ __ADDRESSABLE(sym) \
+ __GENDWARFKSYMS_EXPORT(sym) \
+ asm(__stringify(___EXPORT_SYMBOL(sym, license, ns)))
-#define EXPORT_SYMBOL_GPL_FUTURE(sym) \
- __EXPORT_SYMBOL(sym, "_gpl_future")
+#endif
-#ifdef CONFIG_UNUSED_SYMBOLS
-#define EXPORT_UNUSED_SYMBOL(sym) __EXPORT_SYMBOL(sym, "_unused")
-#define EXPORT_UNUSED_SYMBOL_GPL(sym) __EXPORT_SYMBOL(sym, "_unused_gpl")
+#ifdef DEFAULT_SYMBOL_NAMESPACE
+#define _EXPORT_SYMBOL(sym, license) __EXPORT_SYMBOL(sym, license, DEFAULT_SYMBOL_NAMESPACE)
#else
-#define EXPORT_UNUSED_SYMBOL(sym)
-#define EXPORT_UNUSED_SYMBOL_GPL(sym)
+#define _EXPORT_SYMBOL(sym, license) __EXPORT_SYMBOL(sym, license, "")
#endif
-#endif /* __GENKSYMS__ */
-
-#else /* !CONFIG_MODULES... */
-
-#define EXPORT_SYMBOL(sym)
-#define EXPORT_SYMBOL_GPL(sym)
-#define EXPORT_SYMBOL_GPL_FUTURE(sym)
-#define EXPORT_UNUSED_SYMBOL(sym)
-#define EXPORT_UNUSED_SYMBOL_GPL(sym)
+#define EXPORT_SYMBOL(sym) _EXPORT_SYMBOL(sym, "")
+#define EXPORT_SYMBOL_GPL(sym) _EXPORT_SYMBOL(sym, "GPL")
+#define EXPORT_SYMBOL_NS(sym, ns) __EXPORT_SYMBOL(sym, "", ns)
+#define EXPORT_SYMBOL_NS_GPL(sym, ns) __EXPORT_SYMBOL(sym, "GPL", ns)
-#endif /* CONFIG_MODULES */
-#endif /* !__ASSEMBLY__ */
+#define EXPORT_SYMBOL_FOR_MODULES(sym, mods) __EXPORT_SYMBOL(sym, "GPL", "module:" mods)
#endif /* _LINUX_EXPORT_H */
generated by cgit (git 2.34.1) at 2025-12-22 13:08:56 +0000