Re: [PATCH mm-unstable 2/2] mseal sysmap: enable s390

[Lorenzo Stoakes <lorenzo.stoakes@oracle.com>]

On Tue, Mar 11, 2025 at 01:33:26PM +0100, Heiko Carstens wrote:
> Provide support for CONFIG_MSEAL_SYSTEM_MAPPINGS on s390, covering the
> vdso.
>
> Signed-off-by: Heiko Carstens <hca@linux.ibm.com>

Reviewed-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>

> ---
>  arch/s390/Kconfig       | 1 +
>  arch/s390/kernel/vdso.c | 2 +-
>  2 files changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/arch/s390/Kconfig b/arch/s390/Kconfig
> index 608a965e2344..93b880992596 100644
> --- a/arch/s390/Kconfig
> +++ b/arch/s390/Kconfig
> @@ -141,6 +141,7 @@ config S390
>  	select ARCH_SUPPORTS_DEBUG_PAGEALLOC
>  	select ARCH_SUPPORTS_HUGETLBFS
>  	select ARCH_SUPPORTS_INT128 if CC_HAS_INT128 && CC_IS_CLANG
> +	select ARCH_SUPPORTS_MSEAL_SYSTEM_MAPPINGS

As discussed in 0/2, s390 does not rely on remapping system mappings in any
kind of bizarre way so this is all good.

>  	select ARCH_SUPPORTS_NUMA_BALANCING
>  	select ARCH_SUPPORTS_PER_VMA_LOCK
>  	select ARCH_USE_BUILTIN_BSWAP
> diff --git a/arch/s390/kernel/vdso.c b/arch/s390/kernel/vdso.c
> index 70c8f9ad13cd..430feb1a5013 100644
> --- a/arch/s390/kernel/vdso.c
> +++ b/arch/s390/kernel/vdso.c
> @@ -80,7 +80,7 @@ static int map_vdso(unsigned long addr, unsigned long vdso_mapping_len)
>  	vdso_text_start = vvar_start + VDSO_NR_PAGES * PAGE_SIZE;
>  	/* VM_MAYWRITE for COW so gdb can set breakpoints */
>  	vma = _install_special_mapping(mm, vdso_text_start, vdso_text_len,
> -				       VM_READ|VM_EXEC|
> +				       VM_READ|VM_EXEC|VM_SEALED_SYSMAP|
>  				       VM_MAYREAD|VM_MAYWRITE|VM_MAYEXEC,
>  				       vdso_mapping);
>  	if (IS_ERR(vma)) {
> --
> 2.45.2
>