Re: [PATCH V5 01/26] mm/mmap: Build protect protection_map[] with __P000

[Christophe Leroy <christophe.leroy@csgroup.eu>]

Le 27/06/2022 à 06:58, Anshuman Khandual a écrit :
> Build protect generic protection_map[] array with __P000, so that it can be
> moved inside all the platforms one after the other. Otherwise there will be
> build failures during this process. CONFIG_ARCH_HAS_VM_GET_PAGE_PROT cannot
> be used for this purpose as only certain platforms enable this config now.
> 
> Cc: Andrew Morton <akpm@linux-foundation.org>
> Cc: linux-mm@kvack.org
> Cc: linux-kernel@vger.kernel.org
> Reviewed-by: Christoph Hellwig <hch@lst.de>
> Suggested-by: Christophe Leroy <christophe.leroy@csgroup.eu>
> Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com>

Reviewed-by: Christophe Leroy <christophe.leroy@csgroup.eu>

> ---
>   include/linux/mm.h | 2 ++
>   mm/mmap.c          | 2 ++
>   2 files changed, 4 insertions(+)
> 
> diff --git a/include/linux/mm.h b/include/linux/mm.h
> index bc8f326be0ce..47bfe038d46e 100644
> --- a/include/linux/mm.h
> +++ b/include/linux/mm.h
> @@ -424,7 +424,9 @@ extern unsigned int kobjsize(const void *objp);
>    * mapping from the currently active vm_flags protection bits (the
>    * low four bits) to a page protection mask..
>    */
> +#ifdef __P000
>   extern pgprot_t protection_map[16];
> +#endif
>   
>   /*
>    * The default fault flags that should be used by most of the
> diff --git a/mm/mmap.c b/mm/mmap.c
> index 61e6135c54ef..b01f0280bda2 100644
> --- a/mm/mmap.c
> +++ b/mm/mmap.c
> @@ -101,6 +101,7 @@ static void unmap_region(struct mm_struct *mm,
>    *								w: (no) no
>    *								x: (yes) yes
>    */
> +#ifdef __P000
>   pgprot_t protection_map[16] __ro_after_init = {
>   	[VM_NONE]					= __P000,
>   	[VM_READ]					= __P001,
> @@ -119,6 +120,7 @@ pgprot_t protection_map[16] __ro_after_init = {
>   	[VM_SHARED | VM_EXEC | VM_WRITE]		= __S110,
>   	[VM_SHARED | VM_EXEC | VM_WRITE | VM_READ]	= __S111
>   };
> +#endif
>   
>   #ifndef CONFIG_ARCH_HAS_VM_GET_PAGE_PROT
>   pgprot_t vm_get_page_prot(unsigned long vm_flags)