mirror of
https://github.com/torvalds/linux.git
synced 2025-11-04 02:30:34 +02:00
a979522a1a
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 <maennich@google.com> Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
94 lines
2.5 KiB
Bash
Executable file
94 lines
2.5 KiB
Bash
Executable file
#!/bin/sh
|
|
# SPDX-License-Identifier: GPL-2.0
|
|
|
|
TARGET=$1
|
|
ARCH=$2
|
|
SMP=$3
|
|
PREEMPT=$4
|
|
PREEMPT_RT=$5
|
|
CC_VERSION="$6"
|
|
LD=$7
|
|
|
|
# Do not expand names
|
|
set -f
|
|
|
|
# Fix the language to get consistent output
|
|
LC_ALL=C
|
|
export LC_ALL
|
|
|
|
if [ -z "$KBUILD_BUILD_VERSION" ]; then
|
|
VERSION=$(cat .version 2>/dev/null || echo 1)
|
|
else
|
|
VERSION=$KBUILD_BUILD_VERSION
|
|
fi
|
|
|
|
if [ -z "$KBUILD_BUILD_TIMESTAMP" ]; then
|
|
TIMESTAMP=`date`
|
|
else
|
|
TIMESTAMP=$KBUILD_BUILD_TIMESTAMP
|
|
fi
|
|
if test -z "$KBUILD_BUILD_USER"; then
|
|
LINUX_COMPILE_BY=$(whoami | sed 's/\\/\\\\/')
|
|
else
|
|
LINUX_COMPILE_BY=$KBUILD_BUILD_USER
|
|
fi
|
|
if test -z "$KBUILD_BUILD_HOST"; then
|
|
LINUX_COMPILE_HOST=`uname -n`
|
|
else
|
|
LINUX_COMPILE_HOST=$KBUILD_BUILD_HOST
|
|
fi
|
|
|
|
UTS_VERSION="#$VERSION"
|
|
CONFIG_FLAGS=""
|
|
if [ -n "$SMP" ] ; then CONFIG_FLAGS="SMP"; fi
|
|
if [ -n "$PREEMPT" ] ; then CONFIG_FLAGS="$CONFIG_FLAGS PREEMPT"; fi
|
|
if [ -n "$PREEMPT_RT" ] ; then CONFIG_FLAGS="$CONFIG_FLAGS PREEMPT_RT"; fi
|
|
|
|
# Truncate to maximum length
|
|
UTS_LEN=64
|
|
UTS_VERSION="$(echo $UTS_VERSION $CONFIG_FLAGS $TIMESTAMP | cut -b -$UTS_LEN)"
|
|
|
|
# Generate a temporary compile.h
|
|
|
|
{ echo /\* This file is auto generated, version $VERSION \*/
|
|
if [ -n "$CONFIG_FLAGS" ] ; then echo "/* $CONFIG_FLAGS */"; fi
|
|
|
|
echo \#define UTS_MACHINE \"$ARCH\"
|
|
|
|
echo \#define UTS_VERSION \"$UTS_VERSION\"
|
|
|
|
printf '#define LINUX_COMPILE_BY "%s"\n' "$LINUX_COMPILE_BY"
|
|
echo \#define LINUX_COMPILE_HOST \"$LINUX_COMPILE_HOST\"
|
|
|
|
LD_VERSION=$($LD -v | head -n1 | sed 's/(compatible with [^)]*)//' \
|
|
| sed 's/[[:space:]]*$//')
|
|
printf '#define LINUX_COMPILER "%s"\n' "$CC_VERSION, $LD_VERSION"
|
|
} > .tmpcompile
|
|
|
|
# Only replace the real compile.h if the new one is different,
|
|
# in order to preserve the timestamp and avoid unnecessary
|
|
# recompilations.
|
|
# We don't consider the file changed if only the date/time changed,
|
|
# unless KBUILD_BUILD_TIMESTAMP was explicitly set (e.g. for
|
|
# reproducible builds with that value referring to a commit timestamp).
|
|
# A kernel config change will increase the generation number, thus
|
|
# causing compile.h to be updated (including date/time) due to the
|
|
# changed comment in the
|
|
# first line.
|
|
|
|
if [ -z "$KBUILD_BUILD_TIMESTAMP" ]; then
|
|
IGNORE_PATTERN="UTS_VERSION"
|
|
else
|
|
IGNORE_PATTERN="NOT_A_PATTERN_TO_BE_MATCHED"
|
|
fi
|
|
|
|
if [ -r $TARGET ] && \
|
|
grep -v $IGNORE_PATTERN $TARGET > .tmpver.1 && \
|
|
grep -v $IGNORE_PATTERN .tmpcompile > .tmpver.2 && \
|
|
cmp -s .tmpver.1 .tmpver.2; then
|
|
rm -f .tmpcompile
|
|
else
|
|
echo " UPD $TARGET"
|
|
mv -f .tmpcompile $TARGET
|
|
fi
|
|
rm -f .tmpver.1 .tmpver.2
|