# git rev-parse -q --verify a9f675f950a07d5c1dbcbb97aabac56f5ed085e3^{commit}
a9f675f950a07d5c1dbcbb97aabac56f5ed085e3
already have revision, skipping fetch
# git checkout -q -f -B kisskb a9f675f950a07d5c1dbcbb97aabac56f5ed085e3
# git clean -qxdf
# < git log -1
# commit a9f675f950a07d5c1dbcbb97aabac56f5ed085e3
# Author: Milton Miller <miltonm@us.ibm.com>
# Date:   Thu Jul 16 09:37:04 2020 +1000
# 
#     powerpc/vdso: Fix vdso cpu truncation
#     
#     The code in vdso_cpu_init that exposes the cpu and numa node to
#     userspace via SPRG_VDSO incorrctly masks the cpu to 12 bits. This means
#     that any kernel running on a box with more than 4096 threads (NR_CPUS
#     advertises a limit of of 8192 cpus) would expose userspace to two cpu
#     contexts running at the same time with the same cpu number.
#     
#     Note: I'm not aware of any distro shipping a kernel with support for more
#     than 4096 threads today, nor of any system image that currently exceeds
#     4096 threads. Found via code browsing.
#     
#     Fixes: 18ad51dd342a7eb09dbcd059d0b451b616d4dafc ("powerpc: Add VDSO version of getcpu")
#     Signed-off-by: Milton Miller <miltonm@us.ibm.com>
#     Signed-off-by: Anton Blanchard <anton@linux.ibm.com>
#     Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
#     Link: https://lore.kernel.org/r/20200715233704.1352257-1-anton@ozlabs.org
# < /opt/cross/kisskb/br-sparc64-full-2016.08-613-ge98b4dd/bin/sparc64-linux-gcc --version
# < /opt/cross/kisskb/br-sparc64-full-2016.08-613-ge98b4dd/bin/sparc64-linux-ld --version
# < git log --format=%s --max-count=1 a9f675f950a07d5c1dbcbb97aabac56f5ed085e3
# < make -s -j 10 ARCH=sparc64 O=/kisskb/build/powerpc-next_sparc64-defconfig_sparc64 CROSS_COMPILE=/opt/cross/kisskb/br-sparc64-full-2016.08-613-ge98b4dd/bin/sparc64-linux-  defconfig
# < make -s -j 10 ARCH=sparc64 O=/kisskb/build/powerpc-next_sparc64-defconfig_sparc64 CROSS_COMPILE=/opt/cross/kisskb/br-sparc64-full-2016.08-613-ge98b4dd/bin/sparc64-linux-  help
# make -s -j 10 ARCH=sparc64 O=/kisskb/build/powerpc-next_sparc64-defconfig_sparc64 CROSS_COMPILE=/opt/cross/kisskb/br-sparc64-full-2016.08-613-ge98b4dd/bin/sparc64-linux-  olddefconfig
# make -s -j 10 ARCH=sparc64 O=/kisskb/build/powerpc-next_sparc64-defconfig_sparc64 CROSS_COMPILE=/opt/cross/kisskb/br-sparc64-full-2016.08-613-ge98b4dd/bin/sparc64-linux-  
<stdin>:1511:2: warning: #warning syscall clone3 not implemented [-Wcpp]
WARNING: modpost: EXPORT symbol "_mcount" [vmlinux] version generation failed, symbol will not be versioned.
  kernel: arch/sparc/boot/image is ready
  kernel: arch/sparc/boot/zImage is ready
Completed OK
# rm -rf /kisskb/build/powerpc-next_sparc64-defconfig_sparc64
# Build took: 0:02:40.262341