From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-19.4 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 555CDC433ED for ; Mon, 10 May 2021 10:47:54 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 3848A619AD for ; Mon, 10 May 2021 10:47:54 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232408AbhEJKs5 (ORCPT ); Mon, 10 May 2021 06:48:57 -0400 Received: from mail.kernel.org ([198.145.29.99]:49878 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232788AbhEJKke (ORCPT ); Mon, 10 May 2021 06:40:34 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 8A07961962; Mon, 10 May 2021 10:31:02 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1620642663; bh=SVOuE3lKZ+7W5j0ZS6Z5RC2vmw3qtcOexv18YUv8hhg=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=C0fO+RwUHD4B/gMwljJH8phC52v078wHmPF0Ibb8eu1tiVDLZILCL6hS2ek3FHnou IRwKAHjE/WhK+txsB3QMIfqkC4G6uUnwjhc/lLbsMXFbiHMtQfKmrMyXbLjSiokX8G ip7BloZnvUWtt0pUT3FBVNrmeYKVuX8wzjT7YLpI= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Elliot Berman , Masahiro Yamada Subject: [PATCH 5.4 162/184] kbuild: update config_data.gz only when the content of .config is changed Date: Mon, 10 May 2021 12:20:56 +0200 Message-Id: <20210510101955.422273898@linuxfoundation.org> X-Mailer: git-send-email 2.31.1 In-Reply-To: <20210510101950.200777181@linuxfoundation.org> References: <20210510101950.200777181@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Masahiro Yamada commit 46b41d5dd8019b264717978c39c43313a524d033 upstream. If the timestamp of the .config file is updated, config_data.gz is regenerated, then vmlinux is re-linked. This occurs even if the content of the .config has not changed at all. This issue was mitigated by commit 67424f61f813 ("kconfig: do not write .config if the content is the same"); Kconfig does not update the .config when it ends up with the identical configuration. The issue is remaining when the .config is created by *_defconfig with some config fragment(s) applied on top. This is typical for powerpc and mips, where several *_defconfig targets are constructed by using merge_config.sh. One workaround is to have the copy of the .config. The filechk rule updates the copy, kernel/config_data, by checking the content instead of the timestamp. With this commit, the second run with the same configuration avoids the needless rebuilds. $ make ARCH=mips defconfig all [ snip ] $ make ARCH=mips defconfig all *** Default configuration is based on target '32r2el_defconfig' Using ./arch/mips/configs/generic_defconfig as base Merging arch/mips/configs/generic/32r2.config Merging arch/mips/configs/generic/el.config Merging ./arch/mips/configs/generic/board-boston.config Merging ./arch/mips/configs/generic/board-ni169445.config Merging ./arch/mips/configs/generic/board-ocelot.config Merging ./arch/mips/configs/generic/board-ranchu.config Merging ./arch/mips/configs/generic/board-sead-3.config Merging ./arch/mips/configs/generic/board-xilfpga.config # # configuration written to .config # SYNC include/config/auto.conf CALL scripts/checksyscalls.sh CALL scripts/atomic/check-atomics.sh CHK include/generated/compile.h CHK include/generated/autoksyms.h Reported-by: Elliot Berman Signed-off-by: Masahiro Yamada Signed-off-by: Greg Kroah-Hartman --- kernel/.gitignore | 1 + kernel/Makefile | 9 +++++++-- 2 files changed, 8 insertions(+), 2 deletions(-) --- a/kernel/.gitignore +++ b/kernel/.gitignore @@ -1,4 +1,5 @@ # +/config_data # Generated files # kheaders.md5 --- a/kernel/Makefile +++ b/kernel/Makefile @@ -122,10 +122,15 @@ KCOV_INSTRUMENT_stackleak.o := n $(obj)/configs.o: $(obj)/config_data.gz -targets += config_data.gz -$(obj)/config_data.gz: $(KCONFIG_CONFIG) FORCE +targets += config_data config_data.gz +$(obj)/config_data.gz: $(obj)/config_data FORCE $(call if_changed,gzip) +filechk_cat = cat $< + +$(obj)/config_data: $(KCONFIG_CONFIG) FORCE + $(call filechk,cat) + $(obj)/kheaders.o: $(obj)/kheaders_data.tar.xz quiet_cmd_genikh = CHK $(obj)/kheaders_data.tar.xz