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

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

[Steven Price]

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>
---
 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

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

[Paul Burton]

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
>