diff options
Diffstat (limited to 'include/linux/export.h')
| -rw-r--r-- | include/linux/export.h | 194 |
1 files changed, 58 insertions, 136 deletions
diff --git a/include/linux/export.h b/include/linux/export.h index 8933ff6ad23a..f35d03b4113b 100644 --- a/include/linux/export.h +++ b/include/linux/export.h @@ -2,173 +2,95 @@ #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) -#else -#define THIS_MODULE ((struct module *)0) -#endif - -#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 +#ifdef CONFIG_64BIT +#define __EXPORT_SYMBOL_REF(sym) \ + .balign 8 ASM_NL \ + .quad sym #else -#define __CRC_SYMBOL(sym, sec) +#define __EXPORT_SYMBOL_REF(sym) \ + .balign 4 ASM_NL \ + .long sym #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: + * LLVM integrated assembler cam merge adjacent string literals (like + * C and GNU-as) passed to '.ascii', but not to '.asciz' and chokes on: * - * - If applicable, place a CRC entry in the __kcrctab section. - * - 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. + * .asciz "MODULE_" "kvm" ; */ -#define ___EXPORT_SYMBOL(sym, sec, ns) \ - extern typeof(sym) sym; \ - extern const char __kstrtab_##sym[]; \ - extern const char __kstrtabns_##sym[]; \ - __CRC_SYMBOL(sym, sec); \ - 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 +#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(CONFIG_MODULES) || defined(__DISABLE_EXPORTS) +#if 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) +#define __EXPORT_SYMBOL(sym, license, ns) + +#elif defined(__GENKSYMS__) -#elif defined(CONFIG_TRIM_UNUSED_KSYMS) +#define __EXPORT_SYMBOL(sym, license, ns) __GENKSYMS_EXPORT_SYMBOL(sym) -#include <generated/autoksyms.h> +#elif defined(__ASSEMBLY__) +#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, 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) -#define __cond_export_sym_0(sym, sec, ns) /* nothing */ - +#define __GENDWARFKSYMS_EXPORT(sym) \ + static typeof(sym) *__gendwarfksyms_ptr_##sym __used \ + __section(".discard.gendwarfksyms") = &sym; #else +#define __GENDWARFKSYMS_EXPORT(sym) +#endif -#define __EXPORT_SYMBOL(sym, sec, ns) ___EXPORT_SYMBOL(sym, sec, ns) +#define __EXPORT_SYMBOL(sym, license, ns) \ + extern typeof(sym) sym; \ + __ADDRESSABLE(sym) \ + __GENDWARFKSYMS_EXPORT(sym) \ + asm(__stringify(___EXPORT_SYMBOL(sym, license, ns))) -#endif /* CONFIG_MODULES */ +#endif #ifdef DEFAULT_SYMBOL_NAMESPACE -#include <linux/stringify.h> -#define _EXPORT_SYMBOL(sym, sec) __EXPORT_SYMBOL(sym, sec, __stringify(DEFAULT_SYMBOL_NAMESPACE)) +#define _EXPORT_SYMBOL(sym, license) __EXPORT_SYMBOL(sym, license, DEFAULT_SYMBOL_NAMESPACE) #else -#define _EXPORT_SYMBOL(sym, sec) __EXPORT_SYMBOL(sym, sec, "") +#define _EXPORT_SYMBOL(sym, license) __EXPORT_SYMBOL(sym, license, "") #endif #define EXPORT_SYMBOL(sym) _EXPORT_SYMBOL(sym, "") -#define EXPORT_SYMBOL_GPL(sym) _EXPORT_SYMBOL(sym, "_gpl") -#define EXPORT_SYMBOL_GPL_FUTURE(sym) _EXPORT_SYMBOL(sym, "_gpl_future") -#define EXPORT_SYMBOL_NS(sym, ns) __EXPORT_SYMBOL(sym, "", #ns) -#define EXPORT_SYMBOL_NS_GPL(sym, ns) __EXPORT_SYMBOL(sym, "_gpl", #ns) - -#ifdef CONFIG_UNUSED_SYMBOLS -#define EXPORT_UNUSED_SYMBOL(sym) _EXPORT_SYMBOL(sym, "_unused") -#define EXPORT_UNUSED_SYMBOL_GPL(sym) _EXPORT_SYMBOL(sym, "_unused_gpl") -#else -#define EXPORT_UNUSED_SYMBOL(sym) -#define EXPORT_UNUSED_SYMBOL_GPL(sym) -#endif +#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 /* !__ASSEMBLY__ */ +#define EXPORT_SYMBOL_GPL_FOR_MODULES(sym, mods) __EXPORT_SYMBOL(sym, "GPL", "module:" mods) #endif /* _LINUX_EXPORT_H */ |