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s390: disable -Warray-bounds

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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>
This commit is contained in:
Sven Schnelle 2022-04-25 14:17:42 +02:00 committed by Heiko Carstens
parent af2d861d4c
commit 8b202ee218
1 changed files with 10 additions and 0 deletions
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10
arch/s390/Makefile
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@ -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__