From: Sven Schnelle <svens@linux.ibm.com>
To: Heiko Carstens <hca@linux.ibm.com>
Cc: Vasily Gorbik <gor@linux.ibm.com>,
Alexander Gordeev <agordeev@linux.ibm.com>,
Linus Torvalds <torvalds@linux-foundation.org>,
Kees Cook <keescook@chromium.org>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: [PATCH v2] s390: disable -Warray-bounds
Date: Mon, 25 Apr 2022 14:17:42 +0200 [thread overview]
Message-ID: <20220425121742.3222133-1-svens@linux.ibm.com> (raw)
gcc-12 shows a lot of array bound warnings on s390. This is caused
by our S390_lowcore macro:
which uses an hardcoded address of 0. Wrapping that with
absolute_pointer() works, but gcc no longer knows that a 12 bit
instruction 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 when gcc-12 is used until there is a better real solution.
Signed-off-by: Sven Schnelle <svens@linux.ibm.com>
---
Changes in v2:
- only remove -Warray-bounds for gcc-12
arch/s390/Makefile | 10 ++++++++++
1 file changed, 10 insertions(+)
diff --git a/arch/s390/Makefile b/arch/s390/Makefile
index e441b60b1812..df325eacf62d 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__
--
2.35.1
next reply other threads:[~2022-04-25 12:17 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-04-25 12:17 Sven Schnelle [this message]
2022-04-26 12:18 ` [PATCH v2] s390: disable -Warray-bounds Heiko Carstens
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