linux-kernel - Re: [PATCH V2 14/30] s390/mm: Enable ARCH_HAS_VM_GET_PAGE

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Message-ID: <yt9d7d9oy9uj.fsf@linux.ibm.com>
Date:   Mon, 21 Feb 2022 08:09:24 +0100
From:   Sven Schnelle <svens@...ux.ibm.com>
To:     Anshuman Khandual <anshuman.khandual@....com>
Cc:     linux-mm@...ck.org, akpm@...ux-foundation.org,
        linux-kernel@...r.kernel.org,
        Christoph Hellwig <hch@...radead.org>,
        linux-arch@...r.kernel.org, Heiko Carstens <hca@...ux.ibm.com>,
        Vasily Gorbik <gor@...ux.ibm.com>, linux-s390@...r.kernel.org
Subject: Re: [PATCH V2 14/30] s390/mm: Enable ARCH_HAS_VM_GET_PAGE_PROT

Anshuman Khandual <anshuman.khandual@....com> writes:

> 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@...ux.ibm.com>
> Cc: Vasily Gorbik <gor@...ux.ibm.com>
> Cc: linux-s390@...r.kernel.org
> Cc: linux-kernel@...r.kernel.org
> Signed-off-by: Anshuman Khandual <anshuman.khandual@....com>

Acked-by: Sven Schnelle <svens@...ux.ibm.com>

> ---
>  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);