# git rev-parse -q --verify 8077155dce6c20909682788466ddb25af743cb73^{commit}
8077155dce6c20909682788466ddb25af743cb73
already have revision, skipping fetch
# git checkout -q -f -B kisskb 8077155dce6c20909682788466ddb25af743cb73
# git clean -qxdf
# < git log -1
# commit 8077155dce6c20909682788466ddb25af743cb73
# Author: Nicholas Piggin <npiggin@gmail.com>
# Date:   Fri Nov 20 12:57:57 2020 +1000
# 
#     powerpc/64s: Trim offlined CPUs from mm_cpumasks
#     
#     When offlining a CPU, powerpc/64s does not flush TLBs, rather it just
#     leaves the CPU set in mm_cpumasks, so it continues to receive TLBIEs
#     to manage its TLBs.
#     
#     However the exit_flush_lazy_tlbs() function expects that after
#     returning, all CPUs (except self) have flushed TLBs for that mm, in
#     which case TLBIEL can be used for this flush. This breaks for offline
#     CPUs because they don't get the IPI to flush their TLB. This can lead
#     to stale translations.
#     
#     Fix this by clearing the CPU from mm_cpumasks, then flushing all TLBs
#     before going offline.
#     
#     These offlined CPU bits stuck in the cpumask also prevents the cpumask
#     from being trimmed back to local mode, which means continual broadcast
#     IPIs or TLBIEs are needed for TLB flushing. This patch prevents that
#     situation too.
#     
#     Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
#     Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
#     Link: https://lore.kernel.org/r/20201120025757.325930-3-npiggin@gmail.com
# < /opt/cross/kisskb/korg/gcc-4.9.4-nolibc/powerpc64-linux/bin/powerpc64-linux-gcc --version
# < /opt/cross/kisskb/korg/gcc-4.9.4-nolibc/powerpc64-linux/bin/powerpc64-linux-ld --version
# < git log --format=%s --max-count=1 8077155dce6c20909682788466ddb25af743cb73
# < make -s -j 120 ARCH=powerpc O=/kisskb/build/powerpc-fixes_44x_redwood_defconfig_powerpc-gcc4.9 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-4.9.4-nolibc/powerpc64-linux/bin/powerpc64-linux-  44x/redwood_defconfig
# make -s -j 120 ARCH=powerpc O=/kisskb/build/powerpc-fixes_44x_redwood_defconfig_powerpc-gcc4.9 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-4.9.4-nolibc/powerpc64-linux/bin/powerpc64-linux-  
/kisskb/src/block/genhd.c: In function 'diskstats_show':
/kisskb/src/block/genhd.c:1659:1: warning: the frame size of 1160 bytes is larger than 1024 bytes [-Wframe-larger-than=]
 }
 ^
Completed OK
# rm -rf /kisskb/build/powerpc-fixes_44x_redwood_defconfig_powerpc-gcc4.9
# Build took: 0:00:26.649090