s390: disable -Warray-bounds

Bugzilla: https://bugzilla.redhat.com/2159468

commit 8b202ee
Author: Sven Schnelle <svens@linux.ibm.com>
Date:   Mon Apr 25 14:17:42 2022 +0200

    s390: disable -Warray-bounds

    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: Eric Chanudet <echanude@redhat.com>

Author: eric-ch

arch/s390/Makefile

@@ -32,6 +32,16 @@ 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__