Re: [PATCH v10 05/22] mips: mm: Add p?d_leaf() definitions

[Paul Burton <paul.burton@mips.com>]

Hi Steven,

On Wed, Jul 31, 2019 at 04:45:46PM +0100, Steven Price wrote:
> walk_page_range() is going to be allowed to walk page tables other than
> those of user space. For this it needs to know when it has reached a
> 'leaf' entry in the page tables. This information is provided by the
> p?d_leaf() functions/macros.
> 
> If _PAGE_HUGE is defined we can simply look for it. When not defined we
> can be confident that there are no leaf pages in existence and fall back
> on the generic implementation (added in a later patch) which returns 0.
> 
> CC: Ralf Baechle <ralf@linux-mips.org>
> CC: Paul Burton <paul.burton@mips.com>
> CC: James Hogan <jhogan@kernel.org>
> CC: linux-mips@vger.kernel.org
> Signed-off-by: Steven Price <steven.price@arm.com>

Acked-by: Paul Burton <paul.burton@mips.com>

Thanks,
    Paul

> ---
>  arch/mips/include/asm/pgtable.h | 5 +++++
>  1 file changed, 5 insertions(+)
> 
> diff --git a/arch/mips/include/asm/pgtable.h b/arch/mips/include/asm/pgtable.h
> index 7d27194e3b45..238ca243ad31 100644
> --- a/arch/mips/include/asm/pgtable.h
> +++ b/arch/mips/include/asm/pgtable.h
> @@ -627,6 +627,11 @@ static inline pmd_t pmdp_huge_get_and_clear(struct mm_struct *mm,
>  
>  #endif /* CONFIG_TRANSPARENT_HUGEPAGE */
>  
> +#ifdef _PAGE_HUGE
> +#define pmd_leaf(pmd)	((pmd_val(pmd) & _PAGE_HUGE) != 0)
> +#define pud_leaf(pud)	((pud_val(pud) & _PAGE_HUGE) != 0)
> +#endif
> +
>  #define gup_fast_permitted(start, end)	(!cpu_has_dc_aliases)
>  
>  #include <asm-generic/pgtable.h>
> -- 
> 2.20.1
>