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Message-Id: <20220510154614.154187-5-sashal@kernel.org>
Date: Tue, 10 May 2022 11:46:13 -0400
From: Sasha Levin <sashal@...nel.org>
To: linux-kernel@...r.kernel.org, stable@...r.kernel.org
Cc: Sven Schnelle <svens@...ux.ibm.com>,
Heiko Carstens <hca@...ux.ibm.com>,
Sasha Levin <sashal@...nel.org>, gor@...ux.ibm.com,
agordeev@...ux.ibm.com, linux-s390@...r.kernel.org
Subject: [PATCH AUTOSEL 4.19 5/6] s390: disable -Warray-bounds
From: Sven Schnelle <svens@...ux.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@...ux.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@...ux.ibm.com>
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
arch/s390/Makefile | 10 ++++++++++
1 file changed, 10 insertions(+)
diff --git a/arch/s390/Makefile b/arch/s390/Makefile
index 9a3a698c8fca..4d0082f3de47 100644
--- a/arch/s390/Makefile
+++ b/arch/s390/Makefile
@@ -27,6 +27,16 @@ KBUILD_CFLAGS_DECOMPRESSOR += $(call cc-option,-ffreestanding)
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 := 16384
CHECKFLAGS += -D__s390__ -D__s390x__
--
2.35.1
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