Re: [PATCHv3 04/11] arm64: Calculate size for idmap_pg_dir at compile time

[Mark Rutland]

On Wed, Oct 14, 2015 at 12:20:27PM +0100, Suzuki K. Poulose wrote:
> Now that we can calculate the number of levels required for
> mapping a va width, reserve exact number of pages that would
> be required to cover the idmap. The idmap should be able to handle
> the maximum physical address size supported.
> 
> Cc: Ard Biesheuvel <ard.biesheuvel@xxxxxxxxxx>
> Cc: Mark Rutland <mark.rutland@xxxxxxx>
> Cc: Catalin Marinas <catalin.marinas@xxxxxxx>
> Cc: Will Deacon <will.deacon@xxxxxxx>
> Signed-off-by: Suzuki K. Poulose <suzuki.poulose@xxxxxxx>
> Reviewed-by: Ard Biesheuvel <ard.biesheuvel@xxxxxxxxxx>
> Tested-by: Ard Biesheuvel <ard.biesheuvel@xxxxxxxxxx>
> ---
>  arch/arm64/include/asm/kernel-pgtable.h |    7 +++++--
>  1 file changed, 5 insertions(+), 2 deletions(-)
> 
> diff --git a/arch/arm64/include/asm/kernel-pgtable.h b/arch/arm64/include/asm/kernel-pgtable.h
> index 5876a36..def7168 100644
> --- a/arch/arm64/include/asm/kernel-pgtable.h
> +++ b/arch/arm64/include/asm/kernel-pgtable.h
> @@ -33,16 +33,19 @@
>   * map to pte level. The swapper also maps the FDT (see __create_page_tables
>   * for more information). Note that the number of ID map translation levels
>   * could be increased on the fly if system RAM is out of reach for the default
> - * VA range, so 3 pages are reserved in all cases.
> + * VA range, so pages required to map highest possible PA are reserved in all
> + * cases.
>   */
>  #if ARM64_SWAPPER_USES_SECTION_MAPS
>  #define SWAPPER_PGTABLE_LEVELS	(CONFIG_PGTABLE_LEVELS - 1)
> +#define IDMAP_PGTABLE_LEVELS	(ARM64_HW_PGTABLE_LEVELS(PHYS_MASK_SHIFT) - 1)
>  #else
>  #define SWAPPER_PGTABLE_LEVELS	(CONFIG_PGTABLE_LEVELS)
> +#define IDMAP_PGTABLE_LEVELS	(ARM64_HW_PGTABLE_LEVELS(PHYS_MASK_SHIFT))
>  #endif
>  
>  #define SWAPPER_DIR_SIZE	(SWAPPER_PGTABLE_LEVELS * PAGE_SIZE)
> -#define IDMAP_DIR_SIZE		(3 * PAGE_SIZE)
> +#define IDMAP_DIR_SIZE		(IDMAP_PGTABLE_LEVELS * PAGE_SIZE)

Acked-by: Mark Rutland <mark.rutland@xxxxxxx>

Thanks,
Mark.
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