# git rev-parse -q --verify b1fbfcb4a20949df08dd995927cdc5ad220c128d^{commit}
b1fbfcb4a20949df08dd995927cdc5ad220c128d
already have revision, skipping fetch
# git checkout -q -f -B kisskb b1fbfcb4a20949df08dd995927cdc5ad220c128d
# git clean -qxdf
# < git log -1
# commit b1fbfcb4a20949df08dd995927cdc5ad220c128d
# Author: Masahiro Yamada <yamada.masahiro@socionext.com>
# Date:   Mon Nov 18 13:52:47 2019 +0900
# 
#     kbuild: make single target builds even faster
#     
#     Commit 2dffd23f81a3 ("kbuild: make single target builds much faster")
#     made the situation much better.
#     
#     To improve it even more, apply the similar idea to the top Makefile.
#     Trim unrelated directories from build-dirs.
#     
#     The single build code must be moved above the 'descend' target.
#     
#     Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
#     Tested-by: Jens Axboe <axboe@kernel.dk>
# < /opt/cross/kisskb/korg/gcc-5.5.0-nolibc/powerpc64-linux/bin/powerpc64-linux-gcc --version
# < /opt/cross/kisskb/korg/gcc-5.5.0-nolibc/powerpc64-linux/bin/powerpc64-linux-ld --version
# < git log --format=%s --max-count=1 b1fbfcb4a20949df08dd995927cdc5ad220c128d
# < make -s -j 80 ARCH=powerpc O=/kisskb/build/kbuild_powernv_defconfig_ppc64le-gcc5 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-5.5.0-nolibc/powerpc64-linux/bin/powerpc64-linux-  powernv_defconfig
# make -s -j 80 ARCH=powerpc O=/kisskb/build/kbuild_powernv_defconfig_ppc64le-gcc5 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-5.5.0-nolibc/powerpc64-linux/bin/powerpc64-linux-  
WARNING: vmlinux.o(.text+0x2fc8): Section mismatch in reference from the variable start_here_common to the function .init.text:start_kernel()
The function start_here_common() references
the function __init start_kernel().
This is often because start_here_common lacks a __init 
annotation or the annotation of start_kernel is wrong.

Completed OK
# rm -rf /kisskb/build/kbuild_powernv_defconfig_ppc64le-gcc5
# Build took: 0:02:51.716678