From nobody Tue Dec 16 12:38:42 2025 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 589E729AAF4; Fri, 9 May 2025 20:18:25 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1746821905; cv=none; b=iyXyZBNWsJV/Fe3NKYHI3aCwiw3VbaI+5dy3dObnV7KHgVAvbR6n9KpoCUUHrdXf73thJ3hgU0AH42fWGc039k17ey+XRjdpTYuo2jSbEWykBNVW3P1upIzPMPoCbtRnmxQP7oqlPySW5btJF1ans4MH2U/uA3yvkkwaRKp+pts= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1746821905; c=relaxed/simple; bh=J92Bg9zXyMxGmwqrjnS9kK9B64dzel95HCv0iSVLp0Y=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=H67xDazo+MFVgu1EPHvPGFivCXAWdnsk2Cjfc/sffdpMulLi0dTn8RK+ks9Zc7vChrxa3lBF2mZD339AQppLLjIeBLJVWn+FtoBsqI7knit9rz+nh5wW/33z/YuGtUOOabQQJCo0dVw6rEy6aZo2MgGosWNPHI28npveVJztgnQ= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=kfmVj/sw; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="kfmVj/sw" Received: by smtp.kernel.org (Postfix) with ESMTPSA id A8A3FC4CEF0; Fri, 9 May 2025 20:18:24 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1746821905; bh=J92Bg9zXyMxGmwqrjnS9kK9B64dzel95HCv0iSVLp0Y=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=kfmVj/swclUa0eXpVXNHBVpDrISySXGVn4ArNqUzazp9vgYAnOajrfrnE6uLI+Zc3 GyMLFn3Yqp8TQLm0CM291tJSuwwACkvuVQSVaW2RgKv99W67ef5JYNlyXLKE3EieeF oKTmSgT6O1M6ms9Wv65Pw2flIRBnPnSXJZoUTps8vPyt52OMbXvaXD0o1/ZCsabsnd 7dK9Orj2aJ9ubbQuVRQv50I6hfGSt9zEqLgonvM3N/wsolZHL4r3Amq4I8dmwAbA95 0/S1hMpFMEoJhoMJzxNqw0CfoTIecjEeGFPCF6BQDZtsWxQytCviBC809dKmpUpPS5 KVhALdERi9D7w== From: Josh Poimboeuf To: x86@kernel.org Cc: linux-kernel@vger.kernel.org, Petr Mladek , Miroslav Benes , Joe Lawrence , live-patching@vger.kernel.org, Song Liu , laokz , Jiri Kosina , Marcos Paulo de Souza , Weinan Liu , Fazla Mehrab , Chen Zhongjin , Puranjay Mohan Subject: [PATCH v2 57/62] livepatch/klp-build: Introduce fix-patch-lines script to avoid __LINE__ diff noise Date: Fri, 9 May 2025 13:17:21 -0700 Message-ID: <9de1929a526c40454bb0e839085eaa3ce5bde5ed.1746821544.git.jpoimboe@kernel.org> X-Mailer: git-send-email 2.49.0 In-Reply-To: References: Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" The __LINE__ macro creates challenges for binary diffing. When a .patch file adds or removes lines, it shifts the line numbers for all code below it. This can cause the code generation of functions using __LINE__ to change due to the line number constant being embedded in a MOV instruction, despite there being no semantic difference. Avoid such false positives by adding a fix-patch-lines script which can be used to insert a #line directive in each patch hunk affecting the line numbering. This script will be used by klp-build, which will be introduced in a subsequent patch. Signed-off-by: Josh Poimboeuf --- MAINTAINERS | 1 + scripts/livepatch/fix-patch-lines | 79 +++++++++++++++++++++++++++++++ 2 files changed, 80 insertions(+) create mode 100755 scripts/livepatch/fix-patch-lines diff --git a/MAINTAINERS b/MAINTAINERS index 06f4a10c7209..20f8be69c558 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -13792,6 +13792,7 @@ F: include/linux/livepatch*.h F: kernel/livepatch/ F: kernel/module/livepatch.c F: samples/livepatch/ +F: scripts/livepatch/ F: tools/testing/selftests/livepatch/ =20 LLC (802.2) diff --git a/scripts/livepatch/fix-patch-lines b/scripts/livepatch/fix-patc= h-lines new file mode 100755 index 000000000000..73c5e3dea46e --- /dev/null +++ b/scripts/livepatch/fix-patch-lines @@ -0,0 +1,79 @@ +#!/usr/bin/awk -f +# SPDX-License-Identifier: GPL-2.0 +# +# Use #line directives to preserve original __LINE__ numbers across patche= s to +# avoid unwanted compilation changes. + +BEGIN { + in_hunk =3D 0 + skip =3D 0 +} + +/^--- / { + skip =3D $2 !~ /\.(c|h)$/ + print + next +} + +/^@@/ { + if (skip) { + print + next + } + + in_hunk =3D 1 + + # for @@ -1,3 +1,4 @@: + # 1: line number in old file + # 3: how many lines the hunk covers in old file + # 1: line number in new file + # 4: how many lines the hunk covers in new file + + match($0, /^@@ -([0-9]+)(,([0-9]+))? \+([0-9]+)(,([0-9]+))? @@/, m) + + # Set 'cur' to the old file's line number at the start of the hunk. It + # gets incremented for every context line and every line removal, so + # that it always represents the old file's current line number. + cur =3D m[1] + + # last =3D last line number of current hunk + last =3D cur + (m[3] ? m[3] : 1) - 1 + + need_line_directive =3D 0 + + print + next +} + +{ + if (skip || !in_hunk || $0 ~ /^\\ No newline at end of file/) { + print + next + } + + # change line + if ($0 ~ /^[+-]/) { + # inject #line after this group of changes + need_line_directive =3D 1 + + if ($0 ~ /^-/) + cur++ + + print + next + } + + # If this is the first context line after a group of changes, inject + # the #line directive to force the compiler to correct the line + # numbering to match the original file. + if (need_line_directive) { + print "+#line " cur + need_line_directive =3D 0 + } + + if (cur =3D=3D last) + in_hunk =3D 0 + + cur++ + print +} --=20 2.49.0