From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932387AbcBHUo2 (ORCPT ); Mon, 8 Feb 2016 15:44:28 -0500 Received: from relais.videotron.ca ([24.201.245.36]:61322 "EHLO relais.videotron.ca" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755892AbcBHUnq (ORCPT ); Mon, 8 Feb 2016 15:43:46 -0500 Content-transfer-encoding: 7BIT From: Nicolas Pitre To: Michal Marek , linux-kbuild@vger.kernel.org Cc: linux-kernel@vger.kernel.org, Al Viro , Rusty Russell Subject: [PATCH 2/6] allow for per-symbol configurable EXPORT_SYMBOL() Date: Mon, 08 Feb 2016 15:28:31 -0500 Message-id: <1454963315-20468-3-git-send-email-nicolas.pitre@linaro.org> X-Mailer: git-send-email 2.5.0 In-reply-to: <1454963315-20468-1-git-send-email-nicolas.pitre@linaro.org> References: <1454963315-20468-1-git-send-email-nicolas.pitre@linaro.org> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Similar to include/generated/autoconf.h, include/generated/expsyms.h will contain a list of defines for each EXPORT_SYMBOL() that we want active. The format is: #define __EXPSYM_ 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/expsyms.h may not be known in advance, an empty file is created early on to let the build proceed. Signed-off-by: Nicolas Pitre --- Makefile | 1 + include/linux/export.h | 22 ++++++++++++++++++++-- 2 files changed, 21 insertions(+), 2 deletions(-) diff --git a/Makefile b/Makefile index 6c1a3c2479..3a264129f8 100644 --- a/Makefile +++ b/Makefile @@ -986,6 +986,7 @@ prepare2: prepare3 outputmakefile asm-generic prepare1: prepare2 $(version_h) include/generated/utsrelease.h \ include/config/auto.conf $(cmd_crmodverdir) + $(Q)touch include/generated/expsyms.h archprepare: archheaders archscripts prepare1 scripts_basic diff --git a/include/linux/export.h b/include/linux/export.h index 96e45ea463..f8e4d9da35 100644 --- a/include/linux/export.h +++ b/include/linux/export.h @@ -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_EXPSYMS + +#include +#include + +#define __EXPORT_SYMBOL(sym, sec) \ + __cond_export_sym(sym, sec, config_enabled(__EXPSYM_##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, "") -- 2.5.0