Re: [PATCH] s390: disable -Warray-bounds

Nathan Chancellor
2022-06-09T14:55:26Z

On Wed, Jun 08, 2022 at 04:59:29PM -0700, Linus Torvalds wrote:

Just one small drive by comment in case this ends up going in in one
form or another.

> Makefile | 4 ++++
> arch/s390/Makefile | 10 +---------
> drivers/gpu/drm/imx/ipuv3-crtc.c | 2 +-
> init/Kconfig | 5 +++++
> 4 files changed, 11 insertions(+), 10 deletions(-)
>
> diff --git a/Makefile b/Makefile
> index c43d825a3c4c..b2e93c1a8021 100644
> --- a/Makefile
> +++ b/Makefile
> @@ -788,6 +788,7 @@ stackp-flags-$(CONFIG_STACKPROTECTOR_STRONG) := -fstack-protector-strong
> KBUILD_CFLAGS += $(stackp-flags-y)
>
> KBUILD_CFLAGS-$(CONFIG_WERROR) += -Werror
> +KBUILD_CFLAGS-$(CONFIG_CC_NO_ARRAY_BOUNDS) += -Wno-array-bounds
> KBUILD_CFLAGS += $(KBUILD_CFLAGS-y) $(CONFIG_CC_IMPLICIT_FALLTHROUGH)
>
> ifdef CONFIG_CC_IS_CLANG
> @@ -805,6 +806,9 @@ endif
> KBUILD_CFLAGS += $(call cc-disable-warning, unused-but-set-variable)
> KBUILD_CFLAGS += $(call cc-disable-warning, unused-const-variable)
>
> +# These result in bogus false positives
> +KBUILD_CFLAGS += $(call cc-disable-warning, dangling-pointer)
> +
> ifdef CONFIG_FRAME_POINTER
> KBUILD_CFLAGS += -fno-omit-frame-pointer -fno-optimize-sibling-calls
> else
> diff --git a/arch/s390/Makefile b/arch/s390/Makefile
> index d73611b35164..e1abb0d03824 100644
> --- a/arch/s390/Makefile
> +++ b/arch/s390/Makefile
> @@ -32,15 +32,7 @@ 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
> +KBUILD_CFLAGS_DECOMPRESSOR += $(if $(CC_NO_ARRAY_BOUNDS),-Wno-array-bounds)

I think this should be $(CONFIG_CC_NO_ARRAY_BOUNDS)?

>
> UTS_MACHINE := s390x
> STACK_SIZE := $(if $(CONFIG_KASAN),65536,16384)
> diff --git a/drivers/gpu/drm/imx/ipuv3-crtc.c b/drivers/gpu/drm/imx/ipuv3-crtc.c
> index 9c8829f945b2..f7863d6dea80 100644
> --- a/drivers/gpu/drm/imx/ipuv3-crtc.c
> +++ b/drivers/gpu/drm/imx/ipuv3-crtc.c
> @@ -69,7 +69,7 @@ static void ipu_crtc_disable_planes(struct ipu_crtc *ipu_crtc,
> drm_atomic_crtc_state_for_each_plane(plane, old_crtc_state) {
> if (plane == &ipu_crtc->plane[0]->base)
> disable_full = true;
> - if (&ipu_crtc->plane[1] && plane == &ipu_crtc->plane[1]->base)
> + if (ipu_crtc->plane[1] && plane == &ipu_crtc->plane[1]->base)
> disable_partial = true;
> }
>
> diff --git a/init/Kconfig b/init/Kconfig
> index c984afc489de..ccb1302d6edd 100644
> --- a/init/Kconfig
> +++ b/init/Kconfig
> @@ -885,6 +885,11 @@ config CC_IMPLICIT_FALLTHROUGH
> default "-Wimplicit-fallthrough=5" if CC_IS_GCC && $(cc-option,-Wimplicit-fallthrough=5)
> default "-Wimplicit-fallthrough" if CC_IS_CLANG && $(cc-option,-Wunreachable-code-fallthrough)
>
> +config CC_NO_ARRAY_BOUNDS
> + bool
> + depends on CC_IS_GCC
> + default y if GCC_VERSION >= 120000 && GCC_VERSION < 130000
> +
> #
> # For architectures that know their GCC __int128 support is sound
> #

Cheers,
Nathan