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Commit f2355416 authored by Nicolas Pitre's avatar Nicolas Pitre
Browse files

export.h: allow for per-symbol configurable EXPORT_SYMBOL() 



Similar to include/generated/autoconf.h, include/generated/autoksyms.h
will contain a list of defines for each EXPORT_SYMBOL() that we want
active. The format is:

  #define __KSYM_<symbol_name> 1

This list will be auto-generated with another patch.  For now we only
include the preprocessor magic to automatically create or omit the
corresponding struct kernel_symbol declaration.

Given the content of include/generated/autoksyms.h may not be known in
advance, an empty file is created early on to let the build proceed.

Signed-off-by: default avatarNicolas Pitre <nico@linaro.org>
Acked-by: default avatarRusty Russell <rusty@rustcorp.com.au>
parent 9895c03d

Makefile

+2 −0
Original line number Diff line number Diff line
@@ -998,6 +998,8 @@ prepare2: prepare3 outputmakefile asm-generic 
prepare1: prepare2 $(version_h) include/generated/utsrelease.h \

                   include/config/auto.conf

	$(cmd_crmodverdir)

	$(Q)test -e include/generated/autoksyms.h || \

	    touch   include/generated/autoksyms.h



archprepare: archheaders archscripts prepare1 scripts_basic

include/linux/export.h

+20 −2
Original line number Diff line number Diff line
@@ -38,7 +38,7 @@ extern struct module __this_module; 


#ifdef CONFIG_MODULES



#ifndef __GENKSYMS__

#if defined(__KERNEL__) && !defined(__GENKSYMS__)

#ifdef CONFIG_MODVERSIONS

/* Mark the CRC weak since genksyms apparently decides not to

 * generate a checksums for some symbols */
@@ -53,7 +53,7 @@ extern struct module __this_module; 
#endif



/* For every exported symbol, place a struct in the __ksymtab section */

#define __EXPORT_SYMBOL(sym, sec)				\

#define ___EXPORT_SYMBOL(sym, sec)				\

	extern typeof(sym) sym;					\

	__CRC_SYMBOL(sym, sec)					\

	static const char __kstrtab_##sym[]			\
@@ -65,6 +65,24 @@ extern struct module __this_module; 
	__attribute__((section("___ksymtab" sec "+" #sym), unused))	\

	= { (unsigned long)&sym, __kstrtab_##sym }



#ifdef CONFIG_TRIM_UNUSED_KSYMS



#include <linux/kconfig.h>

#include <generated/autoksyms.h>



#define __EXPORT_SYMBOL(sym, sec)				\

	__cond_export_sym(sym, sec, config_enabled(__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 */



#else

#define __EXPORT_SYMBOL ___EXPORT_SYMBOL

#endif



#define EXPORT_SYMBOL(sym)					\

	__EXPORT_SYMBOL(sym, "")