# git rev-parse -q --verify 81b654c273914704a4bdf580f28d67aaba1094e4^{commit} 81b654c273914704a4bdf580f28d67aaba1094e4 already have revision, skipping fetch # git checkout -q -f -B kisskb 81b654c273914704a4bdf580f28d67aaba1094e4 # git clean -qxdf # < git log -1 # commit 81b654c273914704a4bdf580f28d67aaba1094e4 # Author: Michael Ellerman # 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") # Reviewed-by: Nicholas Piggin # Signed-off-by: Michael Ellerman # < /opt/cross/kisskb/gcc-4.6.3-nolibc/i386-linux/bin/i386-linux-gcc --version # < git log --format=%s --max-count=1 81b654c273914704a4bdf580f28d67aaba1094e4 # < make -s -j 48 ARCH=i386 O=/kisskb/build/powerpc-fixes_i386_defconfig_i386 CROSS_COMPILE=/opt/cross/kisskb/gcc-4.6.3-nolibc/i386-linux/bin/i386-linux- i386_defconfig # make -s -j 48 ARCH=i386 O=/kisskb/build/powerpc-fixes_i386_defconfig_i386 CROSS_COMPILE=/opt/cross/kisskb/gcc-4.6.3-nolibc/i386-linux/bin/i386-linux- CONFIG_CC_STACKPROTECTOR_AUTO: -fstack-protector available but compiler is broken: disabling /kisskb/src/arch/x86/kernel/e820.c: In function 'e820__setup_pci_gap': /kisskb/src/arch/x86/kernel/e820.c:652:2: warning: 'gapstart' 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/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/kernel/rcu/srcutree.c: In function 'init_srcu_struct_fields': /kisskb/src/kernel/rcu/srcutree.c:146:32: warning: 'levelspread[]' may be used uninitialized in this function [-Wuninitialized] /kisskb/src/kernel/rcu/srcutree.c:94:6: note: 'levelspread[]' was declared here /kisskb/src/arch/x86/kernel/apic/io_apic.c: In function 'mp_map_pin_to_irq': /kisskb/src/arch/x86/kernel/apic/io_apic.c:1033:6: warning: 'irq' 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/sound/hda/hdac_regmap.c: In function 'hda_reg_write': /kisskb/src/sound/hda/hdac_regmap.c:282:16: warning: 'err' 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/drivers/dma-buf/reservation.c: In function 'reservation_object_add_shared_fence': /kisskb/src/drivers/dma-buf/reservation.c:207:2: warning: 'k' may be used uninitialized in this function [-Wuninitialized] /kisskb/src/drivers/dma-buf/reservation.c:160:17: note: 'k' was declared here /kisskb/src/net/mac80211/mlme.c: In function 'ieee80211_rx_mgmt_beacon': /kisskb/src/net/mac80211/mlme.c:1352:3: warning: 'pwr_level_cisco' may be used uninitialized in this function [-Wuninitialized] /kisskb/src/net/mac80211/mlme.c:1309:6: note: 'pwr_level_cisco' was declared here Completed OK # rm -rf /kisskb/build/powerpc-fixes_i386_defconfig_i386 # Build took: 0:01:19.144481