# git rev-parse -q --verify d5c243989fb0cb03c74d7340daca3b819f706ee7^{commit}
# git fetch -q -n -f git://gitlab.ozlabs.ibm.com/linuxppc/linux.git fixes-test
warning: The last gc run reported the following. Please correct the root cause
and remove .git/gc.log.
Automatic cleanup will not be performed until the file is removed.

warning: There are too many unreachable loose objects; run 'git prune' to remove them.

# git rev-parse -q --verify d5c243989fb0cb03c74d7340daca3b819f706ee7^{commit}
d5c243989fb0cb03c74d7340daca3b819f706ee7
# git checkout -q -f -B kisskb d5c243989fb0cb03c74d7340daca3b819f706ee7
# git clean -qxdf
# < git log -1
# commit d5c243989fb0cb03c74d7340daca3b819f706ee7
# Author: Christophe Leroy <christophe.leroy@csgroup.eu>
# Date:   Mon Dec 21 06:18:03 2020 +0000
# 
#     powerpc/32: Fix vmap stack - Properly set r1 before activating MMU on syscall too
#     
#     We need r1 to be properly set before activating MMU, otherwise any new
#     exception taken while saving registers into the stack in syscall
#     prologs will use the user stack, which is wrong and will even lockup
#     or crash when KUAP is selected.
#     
#     Do that by switching the meaning of r11 and r1 until we have saved r1
#     to the stack: copy r1 into r11 and setup the new stack pointer in r1.
#     To avoid complicating and impacting all generic and specific prolog
#     code (and more), copy back r1 into r11 once r11 is save onto
#     the stack.
#     
#     We could get rid of copying r1 back and forth at the cost of rewriting
#     everything to use r1 instead of r11 all the way when CONFIG_VMAP_STACK
#     is set, but the effort is probably not worth it for now.
#     
#     Fixes: da7bb43ab9da ("powerpc/32: Fix vmap stack - Properly set r1 before activating MMU")
#     Cc: stable@vger.kernel.org # v5.10+
#     Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
#     Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
#     Link: https://lore.kernel.org/r/a3d819d5c348cee9783a311d5d3f3ba9b48fd219.1608531452.git.christophe.leroy@csgroup.eu
# < /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 d5c243989fb0cb03c74d7340daca3b819f706ee7
# < make -s -j 48 ARCH=powerpc O=/kisskb/build/powerpc-fixes_ppc64le_defconfig_powerpc-gcc5 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-5.5.0-nolibc/powerpc64-linux/bin/powerpc64-linux-  ppc64le_defconfig
# < make -s -j 48 ARCH=powerpc O=/kisskb/build/powerpc-fixes_ppc64le_defconfig_powerpc-gcc5 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-5.5.0-nolibc/powerpc64-linux/bin/powerpc64-linux-  help
# make -s -j 48 ARCH=powerpc O=/kisskb/build/powerpc-fixes_ppc64le_defconfig_powerpc-gcc5 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-5.5.0-nolibc/powerpc64-linux/bin/powerpc64-linux-  olddefconfig
# make -s -j 48 ARCH=powerpc O=/kisskb/build/powerpc-fixes_ppc64le_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_ppc64le_defconfig_powerpc-gcc5
# Build took: 0:03:41.715135