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=-20.2 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 4DECAC6379F for ; Thu, 22 Jul 2021 16:50:33 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 3659260BD3 for ; Thu, 22 Jul 2021 16:50:33 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235451AbhGVQJU (ORCPT ); Thu, 22 Jul 2021 12:09:20 -0400 Received: from mail.kernel.org ([198.145.29.99]:43148 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234947AbhGVQFg (ORCPT ); Thu, 22 Jul 2021 12:05:36 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 9F0A361CBF; Thu, 22 Jul 2021 16:46:08 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1626972369; bh=0DfvojDQtsTjKzPBJI6fP0XKs1/zGyGKKVN5ampn9VE=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=FJTpUKydcRKnQ74UR6E/zwpy4VEmkZ5c9mTRTILAPZD7x8xh82qoA5e5K7LLVl0qU F299+W56EntsF29Q3IQcOGTwKEJ6p8u+bLtf54ONHSzWSooJOf7lr07kbeqfT/eyHP xYJZkTNvamO2gfs8M5SvR4jUH60AYBP1mW16eWrw= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Matthias Maennich , Masahiro Yamada , Sasha Levin Subject: [PATCH 5.13 088/156] kbuild: mkcompile_h: consider timestamp if KBUILD_BUILD_TIMESTAMP is set Date: Thu, 22 Jul 2021 18:31:03 +0200 Message-Id: <20210722155631.229329270@linuxfoundation.org> X-Mailer: git-send-email 2.32.0 In-Reply-To: <20210722155628.371356843@linuxfoundation.org> References: <20210722155628.371356843@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: Matthias Maennich [ Upstream commit a979522a1a88556e42a22ce61bccc58e304cb361 ] To avoid unnecessary recompilations, mkcompile_h does not regenerate compile.h if just the timestamp changed. Though, if KBUILD_BUILD_TIMESTAMP is set, an explicit timestamp for the build was requested, in which case we should not ignore it. If a user follows the documentation for reproducible builds [1] and defines KBUILD_BUILD_TIMESTAMP as the git commit timestamp, a clean build will have the correct timestamp. A subsequent cherry-pick (or amend) changes the commit timestamp and if an incremental build is done with a different KBUILD_BUILD_TIMESTAMP now, that new value is not taken into consideration. But it should for reproducibility. Hence, whenever KBUILD_BUILD_TIMESTAMP is explicitly set, do not ignore UTS_VERSION when making a decision about whether the regenerated version of compile.h should be moved into place. [1] https://www.kernel.org/doc/html/latest/kbuild/reproducible-builds.html Signed-off-by: Matthias Maennich Signed-off-by: Masahiro Yamada Signed-off-by: Sasha Levin --- scripts/mkcompile_h | 14 +++++++++++--- 1 file changed, 11 insertions(+), 3 deletions(-) diff --git a/scripts/mkcompile_h b/scripts/mkcompile_h index 4ae735039daf..a72b154de7b0 100755 --- a/scripts/mkcompile_h +++ b/scripts/mkcompile_h @@ -70,15 +70,23 @@ UTS_VERSION="$(echo $UTS_VERSION $CONFIG_FLAGS $TIMESTAMP | cut -b -$UTS_LEN)" # Only replace the real compile.h if the new one is different, # in order to preserve the timestamp and avoid unnecessary # recompilations. -# We don't consider the file changed if only the date/time changed. +# We don't consider the file changed if only the date/time changed, +# unless KBUILD_BUILD_TIMESTAMP was explicitly set (e.g. for +# reproducible builds with that value referring to a commit timestamp). # A kernel config change will increase the generation number, thus # causing compile.h to be updated (including date/time) due to the # changed comment in the # first line. +if [ -z "$KBUILD_BUILD_TIMESTAMP" ]; then + IGNORE_PATTERN="UTS_VERSION" +else + IGNORE_PATTERN="NOT_A_PATTERN_TO_BE_MATCHED" +fi + if [ -r $TARGET ] && \ - grep -v 'UTS_VERSION' $TARGET > .tmpver.1 && \ - grep -v 'UTS_VERSION' .tmpcompile > .tmpver.2 && \ + grep -v $IGNORE_PATTERN $TARGET > .tmpver.1 && \ + grep -v $IGNORE_PATTERN .tmpcompile > .tmpver.2 && \ cmp -s .tmpver.1 .tmpver.2; then rm -f .tmpcompile else -- 2.30.2