Re: [PATCH V4 10/26] openrisc/mm: Enable ARCH_HAS_VM_GET_PAGE_PROT

[Stafford Horne]

On Fri, Jun 24, 2022 at 10:13:23AM +0530, Anshuman Khandual 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: Jonas Bonn <jonas@xxxxxxxxxxxx>
> Cc: openrisc@xxxxxxxxxxxxxxxxxxxx
> Cc: linux-kernel@xxxxxxxxxxxxxxx
> Signed-off-by: Anshuman Khandual <anshuman.khandual@xxxxxxx>
> ---
>  arch/openrisc/Kconfig               |  1 +
>  arch/openrisc/include/asm/pgtable.h | 18 ------------------
>  arch/openrisc/mm/init.c             | 20 ++++++++++++++++++++
>  3 files changed, 21 insertions(+), 18 deletions(-)
> 
> diff --git a/arch/openrisc/Kconfig b/arch/openrisc/Kconfig
> index e814df4c483c..fe0dfb50eb86 100644
> --- a/arch/openrisc/Kconfig
> +++ b/arch/openrisc/Kconfig
> @@ -10,6 +10,7 @@ config OPENRISC
>  	select ARCH_HAS_DMA_SET_UNCACHED
>  	select ARCH_HAS_DMA_CLEAR_UNCACHED
>  	select ARCH_HAS_SYNC_DMA_FOR_DEVICE
> +	select ARCH_HAS_VM_GET_PAGE_PROT
>  	select COMMON_CLK
>  	select OF
>  	select OF_EARLY_FLATTREE
> diff --git a/arch/openrisc/include/asm/pgtable.h b/arch/openrisc/include/asm/pgtable.h
> index c3abbf71e09f..dcae8aea132f 100644
> --- a/arch/openrisc/include/asm/pgtable.h
> +++ b/arch/openrisc/include/asm/pgtable.h
> @@ -176,24 +176,6 @@ extern void paging_init(void);
>  	__pgprot(_PAGE_ALL | _PAGE_SRE | _PAGE_SWE \
>  		 | _PAGE_SHARED | _PAGE_DIRTY | _PAGE_EXEC | _PAGE_CI)
>  
> -#define __P000	PAGE_NONE
> -#define __P001	PAGE_READONLY_X
> -#define __P010	PAGE_COPY
> -#define __P011	PAGE_COPY_X
> -#define __P100	PAGE_READONLY
> -#define __P101	PAGE_READONLY_X
> -#define __P110	PAGE_COPY
> -#define __P111	PAGE_COPY_X
> -
> -#define __S000	PAGE_NONE
> -#define __S001	PAGE_READONLY_X
> -#define __S010	PAGE_SHARED
> -#define __S011	PAGE_SHARED_X
> -#define __S100	PAGE_READONLY
> -#define __S101	PAGE_READONLY_X
> -#define __S110	PAGE_SHARED
> -#define __S111	PAGE_SHARED_X
> -
>  /* zero page used for uninitialized stuff */
>  extern unsigned long empty_zero_page[2048];
>  #define ZERO_PAGE(vaddr) (virt_to_page(empty_zero_page))
> diff --git a/arch/openrisc/mm/init.c b/arch/openrisc/mm/init.c
> index 3a021ab6f1ae..a654b9dcba91 100644
> --- a/arch/openrisc/mm/init.c
> +++ b/arch/openrisc/mm/init.c
> @@ -208,3 +208,23 @@ void __init mem_init(void)
>  	mem_init_done = 1;
>  	return;
>  }
> +
> +static pgprot_t protection_map[16] __ro_after_init = {
> +	[VM_NONE]					= PAGE_NONE,
> +	[VM_READ]					= PAGE_READONLY_X,
> +	[VM_WRITE]					= PAGE_COPY,
> +	[VM_WRITE | VM_READ]				= PAGE_COPY_X,
> +	[VM_EXEC]					= PAGE_READONLY,
> +	[VM_EXEC | VM_READ]				= PAGE_READONLY_X,
> +	[VM_EXEC | VM_WRITE]				= PAGE_COPY,
> +	[VM_EXEC | VM_WRITE | VM_READ]			= PAGE_COPY_X,
> +	[VM_SHARED]					= PAGE_NONE,
> +	[VM_SHARED | VM_READ]				= PAGE_READONLY_X,
> +	[VM_SHARED | VM_WRITE]				= PAGE_SHARED,
> +	[VM_SHARED | VM_WRITE | VM_READ]		= PAGE_SHARED_X,
> +	[VM_SHARED | VM_EXEC]				= PAGE_READONLY,
> +	[VM_SHARED | VM_EXEC | VM_READ]			= PAGE_READONLY_X,
> +	[VM_SHARED | VM_EXEC | VM_WRITE]		= PAGE_SHARED,
> +	[VM_SHARED | VM_EXEC | VM_WRITE | VM_READ]	= PAGE_SHARED_X
> +};
> +DECLARE_VM_GET_PAGE_PROT

Looks good.

Acked-by: Stafford Horne <shorne@xxxxxxxxx>