# git gc # git rev-parse -q --verify 01b0f0eae0812e80efeee4ee17687e5386335e08^{commit} # git fetch -q -n -f git://gitlab.ozlabs.ibm.com/linuxppc/linux.git fixes-test # git rev-parse -q --verify 01b0f0eae0812e80efeee4ee17687e5386335e08^{commit} 01b0f0eae0812e80efeee4ee17687e5386335e08 # git checkout -q -f -B kisskb 01b0f0eae0812e80efeee4ee17687e5386335e08 # git clean -qxdf # < git log -1 # commit 01b0f0eae0812e80efeee4ee17687e5386335e08 # Author: Nicholas Piggin # 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 # Reviewed-by: Aneesh Kumar K.V # Debugged-by: Milton Miller # Debugged-by: Aneesh Kumar K.V # Debugged-by: Paul Mackerras # Signed-off-by: Michael Ellerman # Link: https://lore.kernel.org/r/20201126102530.691335-5-npiggin@gmail.com # < /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 01b0f0eae0812e80efeee4ee17687e5386335e08 # < make -s -j 48 ARCH=x86_64 O=/kisskb/build/powerpc-fixes_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 48 ARCH=x86_64 O=/kisskb/build/powerpc-fixes_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 48 ARCH=x86_64 O=/kisskb/build/powerpc-fixes_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 48 ARCH=x86_64 O=/kisskb/build/powerpc-fixes_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/powerpc-fixes_x86_64-allnoconfig_x86_64-gcc4.9 # Build took: 0:04:10.994035