# git rev-parse -q --verify aee101d7b95a03078945681dd7f7ea5e4a1e7686^{commit}
aee101d7b95a03078945681dd7f7ea5e4a1e7686
already have revision, skipping fetch
# git checkout -q -f -B kisskb aee101d7b95a03078945681dd7f7ea5e4a1e7686
# git clean -qxdf
# < git log -1
# commit aee101d7b95a03078945681dd7f7ea5e4a1e7686
# Author: Nicholas Piggin <npiggin@gmail.com>
# Date:   Mon Jan 17 23:44:03 2022 +1000
# 
#     powerpc/64s: Mask SRR0 before checking against the masked NIP
#     
#     Commit 314f6c23dd8d ("powerpc/64s: Mask NIP before checking against
#     SRR0") masked off the low 2 bits of the NIP value in the interrupt
#     stack frame in case they are non-zero and mis-compare against a SRR0
#     register value of a CPU which always reads back 0 from the 2 low bits
#     which are reserved.
#     
#     This now causes the opposite problem that an implementation which does
#     implement those bits in SRR0 will mis-compare against the masked NIP
#     value in which they have been cleared. QEMU is one such implementation,
#     and this is allowed by the architecture.
#     
#     This can be triggered by sigfuz by setting low bits of PT_NIP in the
#     signal context.
#     
#     Fix this for now by masking the SRR0 bits as well. Cleaner is probably
#     to sanitise these values before putting them in registers or stack, but
#     this is the quick and backportable fix.
#     
#     Fixes: 314f6c23dd8d ("powerpc/64s: Mask NIP before checking against SRR0")
#     Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
#     Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
#     Link: https://lore.kernel.org/r/20220117134403.2995059-1-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 aee101d7b95a03078945681dd7f7ea5e4a1e7686
# < make -s -j 32 ARCH=powerpc O=/kisskb/build/powerpc-fixes_44x_bluestone_defconfig_powerpc-gcc5 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-5.5.0-nolibc/powerpc64-linux/bin/powerpc64-linux-  44x/bluestone_defconfig
# < make -s -j 32 ARCH=powerpc O=/kisskb/build/powerpc-fixes_44x_bluestone_defconfig_powerpc-gcc5 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-5.5.0-nolibc/powerpc64-linux/bin/powerpc64-linux-  help
# make -s -j 32 ARCH=powerpc O=/kisskb/build/powerpc-fixes_44x_bluestone_defconfig_powerpc-gcc5 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-5.5.0-nolibc/powerpc64-linux/bin/powerpc64-linux-  olddefconfig
# make -s -j 32 ARCH=powerpc O=/kisskb/build/powerpc-fixes_44x_bluestone_defconfig_powerpc-gcc5 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-5.5.0-nolibc/powerpc64-linux/bin/powerpc64-linux-  
Completed OK
# rm -rf /kisskb/build/powerpc-fixes_44x_bluestone_defconfig_powerpc-gcc5
# Build took: 0:00:29.916448