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@xxxxxxxxxxxxxx>
> CC: Paul Burton <paul.burton@xxxxxxxx>
> CC: James Hogan <jhogan@xxxxxxxxxx>
> CC: linux-mips@xxxxxxxxxxxxxxx
> Signed-off-by: Steven Price <steven.price@xxxxxxx>
Acked-by: Paul Burton <paul.burton@xxxxxxxx>
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
>
