[PATCH 2/2] arm64: mm: allow sections for unaligned bases

[Ard Biesheuvel]

On 20 November 2015 at 16:35, Mark Rutland <mark.rutland at arm.com> wrote:
> Callees of __create_mapping may decide to create section mappings if
> sufficient low bits of the physical and virtual addresses they were
> passed are zero. While __create_mapping rounds the virtual base address
> down, it does not similarly round the phyiscal base address down, and
> hence non-zero bits in the physical address can prevent use of a section
> mapping, even where a whole next-level table would be used instead.
>
> Round down the physical base address in __create_mapping to enable all
> callees to always create section mappings when such a mapping is
> possible.
>
> Signed-off-by: Mark Rutland <mark.rutland at arm.com>
> Cc: Ard Biesheuvel <ard.biesheuvel at linaro.org>
> Cc: Catalin Marinas <catalin.marinas at arm.com>
> Cc: Laura Abbott <labbott at fedoraproject.org>
> Cc: Steve Capper <steve.capper at linaro.org>
> Cc: Will Deacon <will.deacon at arm.com>
> ---
>  arch/arm64/mm/mmu.c | 1 +
>  1 file changed, 1 insertion(+)
>

Acked-by: Ard Biesheuvel <ard.biesheuvel at linaro.org>

> diff --git a/arch/arm64/mm/mmu.c b/arch/arm64/mm/mmu.c
> index 3b06afa..6467d57 100644
> --- a/arch/arm64/mm/mmu.c
> +++ b/arch/arm64/mm/mmu.c
> @@ -307,6 +307,7 @@ static void  __create_mapping(struct mm_struct *mm, pgd_t *pgd,
>         if (WARN_ON((phys ^ virt) & ~PAGE_MASK))
>                 return;
>
> +       phys &= PAGE_MASK;
>         addr = virt & PAGE_MASK;
>         length = PAGE_ALIGN(size + (virt & ~PAGE_MASK));
>
> --
> 1.9.1
>