# git rev-parse -q --verify a048a07d7f4535baa4cbad6bc024f175317ab938^{commit}
a048a07d7f4535baa4cbad6bc024f175317ab938
already have revision, skipping fetch
# git checkout -q -f -B kisskb a048a07d7f4535baa4cbad6bc024f175317ab938
# git clean -qxdf
# < git log -1
# commit a048a07d7f4535baa4cbad6bc024f175317ab938
# Author: Nicholas Piggin <npiggin@gmail.com>
# Date:   Tue May 22 09:00:00 2018 +1000
# 
#     powerpc/64s: Add support for a store forwarding barrier at kernel entry/exit
#     
#     On some CPUs we can prevent a vulnerability related to store-to-load
#     forwarding by preventing store forwarding between privilege domains,
#     by inserting a barrier in kernel entry and exit paths.
#     
#     This is known to be the case on at least Power7, Power8 and Power9
#     powerpc CPUs.
#     
#     Barriers must be inserted generally before the first load after moving
#     to a higher privilege, and after the last store before moving to a
#     lower privilege, HV and PR privilege transitions must be protected.
#     
#     Barriers are added as patch sections, with all kernel/hypervisor entry
#     points patched, and the exit points to lower privilge levels patched
#     similarly to the RFI flush patching.
#     
#     Firmware advertisement is not implemented yet, so CPU flush types
#     are hard coded.
#     
#     Thanks to Michal Suchánek for bug fixes and review.
#     
#     Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
#     Signed-off-by: Mauricio Faria de Oliveira <mauricfo@linux.vnet.ibm.com>
#     Signed-off-by: Michael Neuling <mikey@neuling.org>
#     Signed-off-by: Michal Suchánek <msuchanek@suse.de>
#     Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
#     Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
# < /opt/cross/kisskb/gcc-5.2.0-nolibc/powerpc64le-linux/bin/powerpc64le-linux-gcc --version
# < git log --format=%s --max-count=1 a048a07d7f4535baa4cbad6bc024f175317ab938
# < make -s -j 48 ARCH=powerpc O=/kisskb/build/linus_pseries_le_defconfig_ppc64le CROSS_COMPILE=/opt/cross/kisskb/gcc-5.2.0-nolibc/powerpc64le-linux/bin/powerpc64le-linux-  pseries_le_defconfig
# make -s -j 48 ARCH=powerpc O=/kisskb/build/linus_pseries_le_defconfig_ppc64le CROSS_COMPILE=/opt/cross/kisskb/gcc-5.2.0-nolibc/powerpc64le-linux/bin/powerpc64le-linux-  
WARNING: modpost: Found 3 section mismatch(es).
To see full details build your kernel with:
'make CONFIG_DEBUG_SECTION_MISMATCH=y'
Completed OK
# rm -rf /kisskb/build/linus_pseries_le_defconfig_ppc64le
# Build took: 0:02:17.384862