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=-19.7 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,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 7EBD5C12002 for ; Wed, 14 Jul 2021 19:58:46 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 6B0E1613D0 for ; Wed, 14 Jul 2021 19:58:46 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S243258AbhGNUA4 (ORCPT ); Wed, 14 Jul 2021 16:00:56 -0400 Received: from mail.kernel.org ([198.145.29.99]:45596 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S240876AbhGNTuK (ORCPT ); Wed, 14 Jul 2021 15:50:10 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id B738E61459; Wed, 14 Jul 2021 19:46:11 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1626291972; bh=QW36ld2fStFSJxihXCR04GodtNzwukOib+jE0kNjqpE=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=FYDaw/jgcv+AaJ+/oVxZfxxAcNxC0lgWmijoyZ9a+U+cgTmQ88VpOCj/jNxlsRwPJ 94zJuDpTzSrZmriNpus1guFX4yK5EB9EaAysNmRUWru6jGQSwAsYAV2OqtwPbeXl+B Ft2tFYFVO3oZo7iOFot2a7wE0Uw/LETRpuhZn/K2tKDBK1DjEP1/cKAz9QkxthZ6jw 07jkEnoNSNWD2I+IOAh5vmJ73EC3kT+ixB5ZpNLHdrwhdnMEsnhxQrwMKbic0Sibnk wRQHAhc4izKIMEpXQx6wt4BUueJ1/8ZS17PskMv/o0Z/PBkNlcKURxDi8G5r2qMBZN UiSA82V/jFc7A== From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Matthias Maennich , Masahiro Yamada , Sasha Levin , linux-kbuild@vger.kernel.org Subject: [PATCH AUTOSEL 5.4 42/51] kbuild: mkcompile_h: consider timestamp if KBUILD_BUILD_TIMESTAMP is set Date: Wed, 14 Jul 2021 15:45:04 -0400 Message-Id: <20210714194513.54827-42-sashal@kernel.org> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20210714194513.54827-1-sashal@kernel.org> References: <20210714194513.54827-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore 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 d1d757c6edf4..06c1e9e3bc38 100755 --- a/scripts/mkcompile_h +++ b/scripts/mkcompile_h @@ -80,15 +80,23 @@ UTS_TRUNCATE="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