From patchwork Mon Mar 14 02:42:10 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Nicolas Pitre X-Patchwork-Id: 63781 Delivered-To: patch@linaro.org Received: by 10.112.199.169 with SMTP id jl9csp2245246lbc; Sun, 13 Mar 2016 19:43:11 -0700 (PDT) X-Received: by 10.98.65.14 with SMTP id o14mr26303616pfa.151.1457923391843; Sun, 13 Mar 2016 19:43:11 -0700 (PDT) Return-Path: Received: from vger.kernel.org (vger.kernel.org. [209.132.180.67]) by mx.google.com with ESMTP id n79si10532336pfi.149.2016.03.13.19.43.11; Sun, 13 Mar 2016 19:43:11 -0700 (PDT) Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67; Authentication-Results: mx.google.com; spf=pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754602AbcCNCnJ (ORCPT + 30 others); Sun, 13 Mar 2016 22:43:09 -0400 Received: from alt32.smtp-out.videotron.ca ([24.53.0.21]:17290 "EHLO alt32.smtp-out.videotron.ca" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754047AbcCNCnE (ORCPT ); Sun, 13 Mar 2016 22:43:04 -0400 Received: from yoda.home ([96.23.157.65]) by Videotron with SMTP id fITFaWxF4HvYOfITGapee1; Sun, 13 Mar 2016 22:43:02 -0400 X-Authority-Analysis: v=2.1 cv=c6sLOUJl c=1 sm=1 tr=0 a=keA3yYpnlypCNW5BNWqu+w==:117 a=keA3yYpnlypCNW5BNWqu+w==:17 a=L9H7d07YOLsA:10 a=9cW_t1CCXrUA:10 a=s5jvgZ67dGcA:10 a=7OsogOcEt9IA:10 a=KKAkSRfTAAAA:8 a=Tty9oNO6AAAA:8 a=V4Nnv2rFfRtn8YTrWvgA:9 Received: from xanadu.home (xanadu.home [192.168.2.2]) by yoda.home (Postfix) with ESMTP id 1566D2DA045C; Sun, 13 Mar 2016 22:43:01 -0400 (EDT) From: Nicolas Pitre To: Michal Marek Cc: linux-kbuild@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH v6 2/8] allow for per-symbol configurable EXPORT_SYMBOL() Date: Sun, 13 Mar 2016 22:42:10 -0400 Message-Id: <1457923336-2732-3-git-send-email-nicolas.pitre@linaro.org> X-Mailer: git-send-email 2.5.0 In-Reply-To: <1457923336-2732-1-git-send-email-nicolas.pitre@linaro.org> References: <1457923336-2732-1-git-send-email-nicolas.pitre@linaro.org> X-CMAE-Envelope: MS4wfOLspFvt5zNuaVCPIlAovgah+5GHfh6g1Jl1gxo71rCtpGYbZH56wHARW4myYIJ5zPZF536UiXzFcuuv4f7VlwlS9PgH5914BtHKwd1GM6nSdmNu/u80 BjKoEBgLIe/a8CURT3nI9Y86qGKSiacIULGipLlkZ0p/g+Z3aFrOB5N4xwIufohY8bL8sZVjmGs0ThsKrS4vk6Z2Ahg1jdc7hL4BwPz/LglRTuNZrbjVe/dF jniDThYdzEo3f7KR1VyaXg== Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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_ 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: Nicolas Pitre Acked-by: Rusty Russell --- Makefile | 2 ++ include/linux/export.h | 22 ++++++++++++++++++++-- 2 files changed, 22 insertions(+), 2 deletions(-) -- 2.5.0 diff --git a/Makefile b/Makefile index 6c1a3c2479..e916428cf7 100644 --- a/Makefile +++ b/Makefile @@ -986,6 +986,8 @@ 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 diff --git a/include/linux/export.h b/include/linux/export.h index 96e45ea463..77afdb2a25 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_KSYMS + +#include +#include + +#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, "")