# git rev-parse -q --verify b03897cf318dfc47de33a7ecbc7655584266f034^{commit}
b03897cf318dfc47de33a7ecbc7655584266f034
already have revision, skipping fetch
# git checkout -q -f -B kisskb b03897cf318dfc47de33a7ecbc7655584266f034
# git clean -qxdf
# < git log -1
# commit b03897cf318dfc47de33a7ecbc7655584266f034
# Author: Gautham R. Shenoy <ego@linux.vnet.ibm.com>
# Date:   Wed Jul 18 14:03:16 2018 +0530
# 
#     powerpc/powernv: Fix save/restore of SPRG3 on entry/exit from stop (idle)
#     
#     On 64-bit servers, SPRN_SPRG3 and its userspace read-only mirror
#     SPRN_USPRG3 are used as userspace VDSO write and read registers
#     respectively.
#     
#     SPRN_SPRG3 is lost when we enter stop4 and above, and is currently not
#     restored.  As a result, any read from SPRN_USPRG3 returns zero on an
#     exit from stop4 (Power9 only) and above.
#     
#     Thus in this situation, on POWER9, any call from sched_getcpu() always
#     returns zero, as on powerpc, we call __kernel_getcpu() which relies
#     upon SPRN_USPRG3 to report the CPU and NUMA node information.
#     
#     Fix this by restoring SPRN_SPRG3 on wake up from a deep stop state
#     with the sprg_vdso value that is cached in PACA.
#     
#     Fixes: e1c1cfed5432 ("powerpc/powernv: Save/Restore additional SPRs for stop4 cpuidle")
#     Cc: stable@vger.kernel.org # v4.14+
#     Reported-by: Florian Weimer <fweimer@redhat.com>
#     Signed-off-by: Gautham R. Shenoy <ego@linux.vnet.ibm.com>
#     Reviewed-by: Michael Ellerman <mpe@ellerman.id.au>
#     Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
# < /opt/cross/kisskb/br-aarch64-glibc-2016.08-613-ge98b4dd/bin/aarch64-linux-gcc --version
# < git log --format=%s --max-count=1 b03897cf318dfc47de33a7ecbc7655584266f034
# < make -s -j 48 ARCH=arm64 O=/kisskb/build/powerpc-fixes_arm64-defconfig_arm64 CROSS_COMPILE=/opt/cross/kisskb/br-aarch64-glibc-2016.08-613-ge98b4dd/bin/aarch64-linux-  defconfig
# make -s -j 48 ARCH=arm64 O=/kisskb/build/powerpc-fixes_arm64-defconfig_arm64 CROSS_COMPILE=/opt/cross/kisskb/br-aarch64-glibc-2016.08-613-ge98b4dd/bin/aarch64-linux-  
arch/arm64/Makefile:27: ld does not support --fix-cortex-a53-843419; kernel may be susceptible to erratum
arch/arm64/Makefile:40: LSE atomics not supported by binutils
<stdin>:1335:2: warning: #warning syscall rseq not implemented [-Wcpp]
Completed OK
# rm -rf /kisskb/build/powerpc-fixes_arm64-defconfig_arm64
# Build took: 0:03:24.072659