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* [PATCH v10 05/22] mips: mm: Add p?d_leaf() definitions
       [not found] <20190731154603.41797-1-steven.price@arm.com>
@ 2019-07-31 15:45 ` Steven Price
  2019-07-31 18:35   ` Paul Burton
  0 siblings, 1 reply; 2+ messages in thread
From: Steven Price @ 2019-07-31 15:45 UTC (permalink / raw)
  To: linux-mm
  Cc: Steven Price, Andy Lutomirski, Ard Biesheuvel, Arnd Bergmann,
	Borislav Petkov, Catalin Marinas, Dave Hansen, Ingo Molnar,
	James Morse, Jérôme Glisse, Peter Zijlstra,
	Thomas Gleixner, Will Deacon, x86, H. Peter Anvin,
	linux-arm-kernel, linux-kernel, Mark Rutland, Liang, Kan,
	Andrew Morton, Ralf Baechle, Paul Burton, James Hogan,
	linux-mips

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


^ permalink raw reply	[flat|nested] 2+ messages in thread

* Re: [PATCH v10 05/22] mips: mm: Add p?d_leaf() definitions
  2019-07-31 15:45 ` [PATCH v10 05/22] mips: mm: Add p?d_leaf() definitions Steven Price
@ 2019-07-31 18:35   ` Paul Burton
  0 siblings, 0 replies; 2+ messages in thread
From: Paul Burton @ 2019-07-31 18:35 UTC (permalink / raw)
  To: Steven Price
  Cc: linux-mm, Andy Lutomirski, Ard Biesheuvel, Arnd Bergmann,
	Borislav Petkov, Catalin Marinas, Dave Hansen, Ingo Molnar,
	James Morse, Jérôme Glisse, Peter Zijlstra,
	Thomas Gleixner, Will Deacon, x86, H. Peter Anvin,
	linux-arm-kernel, linux-kernel, Mark Rutland, Liang, Kan,
	Andrew Morton, Ralf Baechle, James Hogan, linux-mips

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
> 

^ permalink raw reply	[flat|nested] 2+ messages in thread

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     [not found] <20190731154603.41797-1-steven.price@arm.com>
2019-07-31 15:45 ` [PATCH v10 05/22] mips: mm: Add p?d_leaf() definitions Steven Price
2019-07-31 18:35   ` Paul Burton

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