Re: [PATCH V6 21/26] m68k/mm: Enable ARCH_HAS_VM_GET_PAGE_PROT

[Geert Uytterhoeven <geert@linux-m68k.org>]

Hi Anshuman,

On Thu, Jun 30, 2022 at 7:19 AM Anshuman Khandual
<anshuman.khandual@arm.com> wrote:
> This enables ARCH_HAS_VM_GET_PAGE_PROT on the platform and exports standard
> vm_get_page_prot() implementation via DECLARE_VM_GET_PAGE_PROT, which looks
> up a private and static protection_map[] array. Subsequently all __SXXX and
> __PXXX macros can be dropped which are no longer needed.
>
> Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
> Cc: linux-m68k@lists.linux-m68k.org
> Cc: linux-kernel@vger.kernel.org
> Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com>

Thanks for your patch!

> --- a/arch/m68k/include/asm/mcf_pgtable.h
> +++ b/arch/m68k/include/asm/mcf_pgtable.h
> @@ -91,60 +91,6 @@
>   * for use. In general, the bit positions are xwr, and P-items are
>   * private, the S-items are shared.
>   */

The comment above should be removed, too.

> -#define __P000         PAGE_NONE
> -#define __P001         __pgprot(CF_PAGE_VALID \
> -                                | CF_PAGE_ACCESSED \
> -                                | CF_PAGE_READABLE)

> --- a/arch/m68k/include/asm/motorola_pgtable.h
> +++ b/arch/m68k/include/asm/motorola_pgtable.h
> @@ -83,28 +83,6 @@ extern unsigned long mm_cachebits;
>  #define PAGE_COPY_C    __pgprot(_PAGE_PRESENT | _PAGE_RONLY | _PAGE_ACCESSED)
>  #define PAGE_READONLY_C        __pgprot(_PAGE_PRESENT | _PAGE_RONLY | _PAGE_ACCESSED)

You might move the *_C definitions above into arch/m68k/mm/motorola.c
as well, as they are only used in the latter.

>
> -/*
> - * The m68k can't do page protection for execute, and considers that the same are read.
> - * Also, write permissions imply read permissions. This is the closest we can get..
> - */
> -#define __P000 PAGE_NONE_C
> -#define __P001 PAGE_READONLY_C
> -#define __P010 PAGE_COPY_C
> -#define __P011 PAGE_COPY_C
> -#define __P100 PAGE_READONLY_C
> -#define __P101 PAGE_READONLY_C
> -#define __P110 PAGE_COPY_C
> -#define __P111 PAGE_COPY_C
> -
> -#define __S000 PAGE_NONE_C
> -#define __S001 PAGE_READONLY_C
> -#define __S010 PAGE_SHARED_C
> -#define __S011 PAGE_SHARED_C
> -#define __S100 PAGE_READONLY_C
> -#define __S101 PAGE_READONLY_C
> -#define __S110 PAGE_SHARED_C
> -#define __S111 PAGE_SHARED_C
> -
>  #define pmd_pgtable(pmd) ((pgtable_t)pmd_page_vaddr(pmd))
>
>  /*
> diff --git a/arch/m68k/include/asm/sun3_pgtable.h b/arch/m68k/include/asm/sun3_pgtable.h
> index 5e4e753f0d24..9d919491765b 100644
> --- a/arch/m68k/include/asm/sun3_pgtable.h
> +++ b/arch/m68k/include/asm/sun3_pgtable.h
> @@ -71,23 +71,6 @@
>   * protection settings, valid (implying read and execute) and writeable. These
>   * are as close as we can get...
>   */

The comment above should be removed, too.

> -#define __P000 PAGE_NONE
> -#define __P001 PAGE_READONLY

With the above fixed:
Reviewed-by: Geert Uytterhoeven <geert@linux-m68k.org>
Acked-by: Geert Uytterhoeven <geert@linux-m68k.org>

Gr{oetje,eeting}s,

                        Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds