[PATCH 2/2] arm64: mm: run pgtable_page_ctor() on non-swapper translation table pages

[Suzuki K Poulose]

On 22/07/16 18:32, Ard Biesheuvel wrote:
> The kernel page table creation routines are accessible to other subsystems
> (e.g., EFI) via the create_pgd_mapping() entry point, which allows mappings
> to be created that are not covered by init_mm.
>
> Since generic code such as apply_to_page_range() may expect translation
> table pages that are not associated with init_mm to be covered by fully
> constructed struct pages, add a call to pgtable_page_ctor() in the alloc
> function used by create_pgd_mapping. Since it is no longer used by
> create_mapping_late(), also update the name of this function to better
> reflect its purpose.
>
> Signed-off-by: Ard Biesheuvel <ard.biesheuvel at linaro.org>
> ---
>  arch/arm64/mm/mmu.c | 9 ++++++---
>  1 file changed, 6 insertions(+), 3 deletions(-)
>
> diff --git a/arch/arm64/mm/mmu.c b/arch/arm64/mm/mmu.c
> index 33f36cede02d..51a558195bb9 100644
> --- a/arch/arm64/mm/mmu.c
> +++ b/arch/arm64/mm/mmu.c
> @@ -268,10 +268,11 @@ static void __create_pgd_mapping(pgd_t *pgdir, phys_addr_t phys,
>  	} while (pgd++, addr = next, addr != end);
>  }
>
> -static phys_addr_t late_pgtable_alloc(void)
> +static phys_addr_t pgd_pgtable_alloc(void)
>  {
>  	void *ptr = (void *)__get_free_page(PGALLOC_GFP);
> -	BUG_ON(!ptr);
> +	if (!ptr || !pgtable_page_ctor(virt_to_page(ptr)))

Should we free the page and return NULL when we encounter an error
in pgtable_page_ctor(), like the rest of the callers ?


> +		BUG();

Otherwise, looks good to me.

Suzuki