# git rev-parse -q --verify 01b0f0eae0812e80efeee4ee17687e5386335e08^{commit}
01b0f0eae0812e80efeee4ee17687e5386335e08
already have revision, skipping fetch
# git checkout -q -f -B kisskb 01b0f0eae0812e80efeee4ee17687e5386335e08
# git clean -qxdf
# < git log -1
# commit 01b0f0eae0812e80efeee4ee17687e5386335e08
# Author: Nicholas Piggin <npiggin@gmail.com>
# Date:   Thu Nov 26 20:25:30 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.
#     
#     A cast of many were involved in working this out, but in particular
#     Milton, Aneesh, Paul made key discoveries.
#     
#     Fixes: 0cef77c7798a7 ("powerpc/64s/radix: flush remote CPUs out of single-threaded mm_cpumask")
#     Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
#     Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
#     Debugged-by: Milton Miller <miltonm@us.ibm.com>
#     Debugged-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
#     Debugged-by: Paul Mackerras <paulus@samba.org>
#     Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
#     Link: https://lore.kernel.org/r/20201126102530.691335-5-npiggin@gmail.com
# < /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 01b0f0eae0812e80efeee4ee17687e5386335e08
# < make -s -j 120 ARCH=powerpc O=/kisskb/build/powerpc-fixes_pmac32_defconfig+KVM_powerpc-gcc5 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-5.5.0-nolibc/powerpc64-linux/bin/powerpc64-linux-  pmac32_defconfig
# Added to kconfig CONFIG_VIRTUALIZATION=y
# Added to kconfig CONFIG_KVM=y
# Added to kconfig CONFIG_KVM_BOOK3S_32=m
# Added to kconfig 
# yes \n | make -s -j 120 ARCH=powerpc O=/kisskb/build/powerpc-fixes_pmac32_defconfig+KVM_powerpc-gcc5 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-5.5.0-nolibc/powerpc64-linux/bin/powerpc64-linux-  oldconfig
yes: standard output: Broken pipe
# make -s -j 120 ARCH=powerpc O=/kisskb/build/powerpc-fixes_pmac32_defconfig+KVM_powerpc-gcc5 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-5.5.0-nolibc/powerpc64-linux/bin/powerpc64-linux-  
INFO: Uncompressed kernel (size 0xa138e4) overlaps the address of the wrapper(0x400000)
INFO: Fixing the link_address of wrapper to (0xb00000)
Completed OK
# rm -rf /kisskb/build/powerpc-fixes_pmac32_defconfig+KVM_powerpc-gcc5
# Build took: 0:01:02.457226