Re: [PATCH V2 14/30] s390/mm: Enable ARCH_HAS_VM_GET_PAGE_PROT

[Alexander Gordeev]

On Mon, Feb 21, 2022 at 12:08:23PM +0530, Anshuman Khandual wrote:
> This defines and exports a platform specific custom vm_get_page_prot() via
> subscribing ARCH_HAS_VM_GET_PAGE_PROT. Subsequently all __SXXX and __PXXX
> macros can be dropped which are no longer needed.
> 
> Cc: Heiko Carstens <hca@xxxxxxxxxxxxx>
> Cc: Vasily Gorbik <gor@xxxxxxxxxxxxx>
> Cc: linux-s390@xxxxxxxxxxxxxxx
> Cc: linux-kernel@xxxxxxxxxxxxxxx
> Signed-off-by: Anshuman Khandual <anshuman.khandual@xxxxxxx>

Acked-by: Alexander Gordeev <agordeev@xxxxxxxxxxxxx>

> ---
>  arch/s390/Kconfig               |  1 +
>  arch/s390/include/asm/pgtable.h | 17 -----------------
>  arch/s390/mm/mmap.c             | 33 +++++++++++++++++++++++++++++++++
>  3 files changed, 34 insertions(+), 17 deletions(-)
> 
> diff --git a/arch/s390/Kconfig b/arch/s390/Kconfig
> index be9f39fd06df..cb1b487e8201 100644
> --- a/arch/s390/Kconfig
> +++ b/arch/s390/Kconfig
> @@ -78,6 +78,7 @@ config S390
>  	select ARCH_HAS_SYSCALL_WRAPPER
>  	select ARCH_HAS_UBSAN_SANITIZE_ALL
>  	select ARCH_HAS_VDSO_DATA
> +	select ARCH_HAS_VM_GET_PAGE_PROT
>  	select ARCH_HAVE_NMI_SAFE_CMPXCHG
>  	select ARCH_INLINE_READ_LOCK
>  	select ARCH_INLINE_READ_LOCK_BH
> diff --git a/arch/s390/include/asm/pgtable.h b/arch/s390/include/asm/pgtable.h
> index 008a6c856fa4..3893ef64b439 100644
> --- a/arch/s390/include/asm/pgtable.h
> +++ b/arch/s390/include/asm/pgtable.h
> @@ -422,23 +422,6 @@ static inline int is_module_addr(void *addr)
>   * implies read permission.
>   */
>           /*xwr*/
> -#define __P000	PAGE_NONE
> -#define __P001	PAGE_RO
> -#define __P010	PAGE_RO
> -#define __P011	PAGE_RO
> -#define __P100	PAGE_RX
> -#define __P101	PAGE_RX
> -#define __P110	PAGE_RX
> -#define __P111	PAGE_RX
> -
> -#define __S000	PAGE_NONE
> -#define __S001	PAGE_RO
> -#define __S010	PAGE_RW
> -#define __S011	PAGE_RW
> -#define __S100	PAGE_RX
> -#define __S101	PAGE_RX
> -#define __S110	PAGE_RWX
> -#define __S111	PAGE_RWX
>  
>  /*
>   * Segment entry (large page) protection definitions.
> diff --git a/arch/s390/mm/mmap.c b/arch/s390/mm/mmap.c
> index e54f928503c5..e99c198aa5de 100644
> --- a/arch/s390/mm/mmap.c
> +++ b/arch/s390/mm/mmap.c
> @@ -188,3 +188,36 @@ void arch_pick_mmap_layout(struct mm_struct *mm, struct rlimit *rlim_stack)
>  		mm->get_unmapped_area = arch_get_unmapped_area_topdown;
>  	}
>  }
> +
> +pgprot_t vm_get_page_prot(unsigned long vm_flags)
> +{
> +	switch (vm_flags & (VM_READ | VM_WRITE | VM_EXEC | VM_SHARED)) {
> +	case VM_NONE:
> +		return PAGE_NONE;
> +	case VM_READ:
> +	case VM_WRITE:
> +	case VM_WRITE | VM_READ:
> +		return PAGE_RO;
> +	case VM_EXEC:
> +	case VM_EXEC | VM_READ:
> +	case VM_EXEC | VM_WRITE:
> +	case VM_EXEC | VM_WRITE | VM_READ:
> +		return PAGE_RX;
> +	case VM_SHARED:
> +		return PAGE_NONE;
> +	case VM_SHARED | VM_READ:
> +		return PAGE_RO;
> +	case VM_SHARED | VM_WRITE:
> +	case VM_SHARED | VM_WRITE | VM_READ:
> +		return PAGE_RW;
> +	case VM_SHARED | VM_EXEC:
> +	case VM_SHARED | VM_EXEC | VM_READ:
> +		return PAGE_RX;
> +	case VM_SHARED | VM_EXEC | VM_WRITE:
> +	case VM_SHARED | VM_EXEC | VM_WRITE | VM_READ:
> +		return PAGE_RWX;
> +	default:
> +		BUILD_BUG();
> +	}
> +}
> +EXPORT_SYMBOL(vm_get_page_prot);
> -- 
> 2.25.1
>