Re: [PATCH 5/6] s390/Kconfig: Select ARCH_SUPPORTS_CFI

[Nathan Chancellor <nathan@kernel.org>]

Hi Heiko,

On Fri, Jul 24, 2026 at 04:13:17PM +0200, Heiko Carstens wrote:
> With all prerequisites in place select ARCH_SUPPORTS_CFI.
> 
> Note that this support is supposed to work with the generic kcfi support
> which is provided by clang. This comes with a couple of limitations:

Consider adding

  select ARCH_USES_CFI_GENERIC_LLVM_PASS if CC_IS_CLANG

to this change in case there are problems such as the one worked around
by commit c57f5fee54df ("libeth: xdp: Disable generic kCFI pass for
libeth_xdp_tx_xmit_bulk()"). Whenever clang grows an s390 backend
expansion for kCFI, that can be version gated pretty easily.

I will test this series fully next week.

> ---
>  arch/s390/Kconfig | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/arch/s390/Kconfig b/arch/s390/Kconfig
> index 84404e6778d5..d57a6c02f51d 100644
> --- a/arch/s390/Kconfig
> +++ b/arch/s390/Kconfig
> @@ -144,6 +144,7 @@ config S390
>  	select ARCH_MHP_MEMMAP_ON_MEMORY_ENABLE
>  	select ARCH_STACKWALK
>  	select ARCH_SUPPORTS_ATOMIC_RMW
> +	select ARCH_SUPPORTS_CFI
>  	select ARCH_SUPPORTS_DEBUG_PAGEALLOC
>  	select ARCH_SUPPORTS_HUGETLBFS
>  	select ARCH_SUPPORTS_INT128 if CC_HAS_INT128 && CC_IS_CLANG
> -- 
> 2.53.0
> 

-- 
Cheers,
Nathan