# git rev-parse -q --verify 7c8db8431b5bc1c37f6d2ce73d2e18a42b52c87d^{commit}
7c8db8431b5bc1c37f6d2ce73d2e18a42b52c87d
already have revision, skipping fetch
# git checkout -q -f -B kisskb 7c8db8431b5bc1c37f6d2ce73d2e18a42b52c87d
# git clean -qxdf
# < git log -1
# commit 7c8db8431b5bc1c37f6d2ce73d2e18a42b52c87d
# Author: Michael Ellerman <mpe@ellerman.id.au>
# Date:   Thu Apr 12 22:24:45 2018 +1000
# 
#     powerpc/64s: Fix CPU_FTRS_ALWAYS vs DT CPU features
#     
#     The cpu_has_feature() mechanism has an optimisation where at build
#     time we construct a mask of the CPU feature bits that will always be
#     true for the given .config, based on the platform/bitness/etc. that we
#     are building for.
#     
#     That is incompatible with DT CPU features, where the set of CPU
#     features is dependent on feature flags that are given to us by
#     firmware.
#     
#     The result is that some feature bits can not be *disabled* by DT CPU
#     features. Or more accurately, they can be disabled but they will still
#     appear in the ALWAYS mask, meaning cpu_has_feature() will always
#     return true for them.
#     
#     In the past this hasn't really been a problem because on Book3S
#     64 (where we support DT CPU features), the set of ALWAYS bits has been
#     very small. That was because we always built for POWER4 and later,
#     meaning the set of common bits was small.
#     
#     The only bit that could be cleared by DT CPU features that was also in
#     the ALWAYS mask was CPU_FTR_NODSISRALIGN, and that was only used in
#     the alignment handler to create a fake DSISR. That code was itself
#     deleted in 31bfdb036f12 ("powerpc: Use instruction emulation
#     infrastructure to handle alignment faults") (Sep 2017).
#     
#     However the set of ALWAYS features changed with the recent commit
#     db5ae1c155af ("powerpc/64s: Refine feature sets for little endian
#     builds") which restricted the set of feature flags when building
#     little endian to Power7 or later. That caused the ALWAYS mask to
#     become much larger for little endian builds.
#     
#     The result is that the following feature bits can currently not
#     be *disabled* by DT CPU features:
#     
#       CPU_FTR_REAL_LE, CPU_FTR_MMCRA, CPU_FTR_CTRL, CPU_FTR_SMT,
#       CPU_FTR_PURR, CPU_FTR_SPURR, CPU_FTR_DSCR, CPU_FTR_PKEY,
#       CPU_FTR_VMX_COPY, CPU_FTR_CFAR, CPU_FTR_HAS_PPR.
#     
#     To fix it we need to mask the set of ALWAYS features with the base set
#     of DT CPU features, ie. the features that are always enabled by DT CPU
#     features. That way there are no bits in the ALWAYS mask that are not
#     also always set by DT CPU features.
#     
#     Fixes: db5ae1c155af ("powerpc/64s: Refine feature sets for little endian builds")
#     Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
# < /opt/cross/kisskb/gcc-4.6.3-nolibc/powerpc-linux/bin/powerpc-linux-gcc --version
# < git log --format=%s --max-count=1 7c8db8431b5bc1c37f6d2ce73d2e18a42b52c87d
# < make -s -j 80 ARCH=powerpc O=/kisskb/build/powerpc-fixes_pseries_defconfig+POWERNV=n_powerpc CROSS_COMPILE=/opt/cross/kisskb/gcc-4.6.3-nolibc/powerpc-linux/bin/powerpc-linux-  pseries_defconfig
# Added to kconfig CONFIG_PPC_POWERNV=n
# yes \n | make -s -j 80 ARCH=powerpc O=/kisskb/build/powerpc-fixes_pseries_defconfig+POWERNV=n_powerpc CROSS_COMPILE=/opt/cross/kisskb/gcc-4.6.3-nolibc/powerpc-linux/bin/powerpc-linux-  oldconfig
yes: standard output: Broken pipe
yes: write error
# make -s -j 80 ARCH=powerpc O=/kisskb/build/powerpc-fixes_pseries_defconfig+POWERNV=n_powerpc CROSS_COMPILE=/opt/cross/kisskb/gcc-4.6.3-nolibc/powerpc-linux/bin/powerpc-linux-  
/kisskb/src/net/bridge/br_netlink.c: In function 'br_afspec':
/kisskb/src/net/bridge/br_netlink.c:635:7: warning: 'err' may be used uninitialized in this function [-Wuninitialized]
/kisskb/src/kernel/printk/printk.c: In function 'devkmsg_sysctl_set_loglvl':
/kisskb/src/kernel/printk/printk.c:182:16: warning: 'old' may be used uninitialized in this function [-Wuninitialized]
/kisskb/src/kernel/cgroup/cgroup-v1.c: In function 'cgroup1_mount':
/kisskb/src/kernel/cgroup/cgroup-v1.c:1268:20: warning: 'root' may be used uninitialized in this function [-Wuninitialized]
/kisskb/src/drivers/base/regmap/regmap.c: In function 'regmap_raw_read':
/kisskb/src/drivers/base/regmap/regmap.c:2497:6: warning: 'ret' may be used uninitialized in this function [-Wuninitialized]
/kisskb/src/drivers/base/regmap/regmap.c: In function '_regmap_raw_write':
/kisskb/src/drivers/base/regmap/regmap.c:1819:6: warning: 'ret' may be used uninitialized in this function [-Wuninitialized]
/kisskb/src/mm/swap_state.c: In function '__add_to_swap_cache':
/kisskb/src/mm/swap_state.c:135:5: warning: 'error' may be used uninitialized in this function [-Wuninitialized]
/kisskb/src/mm/hugetlb.c: In function 'alloc_pool_huge_page':
/kisskb/src/mm/hugetlb.c:1433:5: warning: 'page' may be used uninitialized in this function [-Wuninitialized]
/kisskb/src/fs/nfsd/nfs4xdr.c: In function 'nfsd4_encode_components_esc':
/kisskb/src/fs/nfsd/nfs4xdr.c:2041:9: warning: 'str' may be used uninitialized in this function [-Wuninitialized]
/kisskb/src/drivers/net/tun.c: In function 'tun_get_user':
/kisskb/src/drivers/net/tun.c:1820:30: warning: 'copylen' may be used uninitialized in this function [-Wuninitialized]
/kisskb/src/drivers/net/tun.c:1730:46: warning: 'linear' may be used uninitialized in this function [-Wuninitialized]
/kisskb/src/drivers/tty/serial/8250/8250_core.c: In function 'univ8250_release_irq':
/kisskb/src/drivers/tty/serial/8250/8250_core.c:251:18: warning: 'i' may be used uninitialized in this function [-Wuninitialized]
/kisskb/src/drivers/tty/serial/8250/8250_core.c:231:19: note: 'i' was declared here
Completed OK
# rm -rf /kisskb/build/powerpc-fixes_pseries_defconfig+POWERNV=n_powerpc
# Build took: 0:02:45.553562