From: Sven Schnelle svens@linux.ibm.com
[ Upstream commit 8b202ee218395319aec1ef44f72043e1fbaccdd6 ]
gcc-12 shows a lot of array bound warnings on s390. This is caused by the S390_lowcore macro which uses a hardcoded address of 0.
Wrapping that with absolute_pointer() works, but gcc no longer knows that a 12 bit displacement is sufficient to access lowcore. So it emits instructions like 'lghi %r1,0; l %rx,xxx(%r1)' instead of a single load/store instruction. As s390 stores variables often read/written in lowcore, this is considered problematic. Therefore disable -Warray-bounds on s390 for gcc-12 for the time being, until there is a better solution.
Signed-off-by: Sven Schnelle svens@linux.ibm.com Link: https://lore.kernel.org/r/yt9dzgkelelc.fsf@linux.ibm.com Link: https://lore.kernel.org/r/20220422134308.1613610-1-svens@linux.ibm.com Link: https://lore.kernel.org/r/20220425121742.3222133-1-svens@linux.ibm.com Signed-off-by: Heiko Carstens hca@linux.ibm.com Signed-off-by: Sasha Levin sashal@kernel.org --- arch/s390/Makefile | 10 ++++++++++ 1 file changed, 10 insertions(+)
diff --git a/arch/s390/Makefile b/arch/s390/Makefile index 609e3697324b..6e42252214dd 100644 --- a/arch/s390/Makefile +++ b/arch/s390/Makefile @@ -30,6 +30,16 @@ KBUILD_CFLAGS_DECOMPRESSOR += -fno-stack-protector KBUILD_CFLAGS_DECOMPRESSOR += $(call cc-disable-warning, address-of-packed-member) KBUILD_CFLAGS_DECOMPRESSOR += $(if $(CONFIG_DEBUG_INFO),-g) KBUILD_CFLAGS_DECOMPRESSOR += $(if $(CONFIG_DEBUG_INFO_DWARF4), $(call cc-option, -gdwarf-4,)) + +ifdef CONFIG_CC_IS_GCC + ifeq ($(call cc-ifversion, -ge, 1200, y), y) + ifeq ($(call cc-ifversion, -lt, 1300, y), y) + KBUILD_CFLAGS += $(call cc-disable-warning, array-bounds) + KBUILD_CFLAGS_DECOMPRESSOR += $(call cc-disable-warning, array-bounds) + endif + endif +endif + UTS_MACHINE := s390x STACK_SIZE := $(if $(CONFIG_KASAN),65536,16384) CHECKFLAGS += -D__s390__ -D__s390x__