# git rev-parse -q --verify a979522a1a88556e42a22ce61bccc58e304cb361^{commit}
# git fetch -q -n -f git://gitlab.ozlabs.ibm.com/mirror/linux-kbuild.git for-next
warning: The last gc run reported the following. Please correct the root cause
and remove .git/gc.log.
Automatic cleanup will not be performed until the file is removed.

warning: There are too many unreachable loose objects; run 'git prune' to remove them.

# git rev-parse -q --verify a979522a1a88556e42a22ce61bccc58e304cb361^{commit}
a979522a1a88556e42a22ce61bccc58e304cb361
# git checkout -q -f -B kisskb a979522a1a88556e42a22ce61bccc58e304cb361
# git clean -qxdf
# < git log -1
# commit a979522a1a88556e42a22ce61bccc58e304cb361
# Author: Matthias Maennich <maennich@google.com>
# Date:   Sat Jun 12 15:18:38 2021 +0100
# 
#     kbuild: mkcompile_h: consider timestamp if KBUILD_BUILD_TIMESTAMP is set
#     
#     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>
# < /opt/cross/kisskb/korg/gcc-4.9.4-nolibc/x86_64-linux/bin/x86_64-linux-gcc --version
# < /opt/cross/kisskb/korg/gcc-4.9.4-nolibc/x86_64-linux/bin/x86_64-linux-ld --version
# < git log --format=%s --max-count=1 a979522a1a88556e42a22ce61bccc58e304cb361
# < make -s -j 8 ARCH=x86_64 O=/kisskb/build/kbuild_x86_64-allnoconfig_x86_64-gcc4.9 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-4.9.4-nolibc/x86_64-linux/bin/x86_64-linux-  allnoconfig
# < make -s -j 8 ARCH=x86_64 O=/kisskb/build/kbuild_x86_64-allnoconfig_x86_64-gcc4.9 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-4.9.4-nolibc/x86_64-linux/bin/x86_64-linux-  help
# make -s -j 8 ARCH=x86_64 O=/kisskb/build/kbuild_x86_64-allnoconfig_x86_64-gcc4.9 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-4.9.4-nolibc/x86_64-linux/bin/x86_64-linux-  olddefconfig
# make -s -j 8 ARCH=x86_64 O=/kisskb/build/kbuild_x86_64-allnoconfig_x86_64-gcc4.9 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-4.9.4-nolibc/x86_64-linux/bin/x86_64-linux-  
Completed OK
# rm -rf /kisskb/build/kbuild_x86_64-allnoconfig_x86_64-gcc4.9
# Build took: 0:00:51.886658