| /* SPDX-License-Identifier: GPL-2.0-only */ |
| #ifndef _LINUX_EXPORT_H |
| #define _LINUX_EXPORT_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. |
| */ |
| |
| #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 |
| #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. |
| */ |
| #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: |
| * |
| * - 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. |
| */ |
| #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 |
| |
| #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) |
| |
| #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) |
| #define __cond_export_sym_0(sym, sec, ns) /* nothing */ |
| |
| #else |
| |
| #define __EXPORT_SYMBOL(sym, sec, ns) ___EXPORT_SYMBOL(sym, sec, ns) |
| |
| #endif /* CONFIG_MODULES */ |
| |
| #ifdef DEFAULT_SYMBOL_NAMESPACE |
| #include <linux/stringify.h> |
| #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, "") |
| #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__ */ |
| |
| #endif /* _LINUX_EXPORT_H */ |