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* [PATCH v17 05/23] mips: mm: Add p?d_leaf() definitions
       [not found] <20191218162402.45610-1-steven.price@arm.com>
@ 2019-12-18 16:23 ` Steven Price
  0 siblings, 0 replies; only message in thread
From: Steven Price @ 2019-12-18 16:23 UTC (permalink / raw)
  To: Andrew Morton, 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,
	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>
Acked-by: Paul Burton <paul.burton@mips.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 91b89aab1787..aef5378f909c 100644
--- a/arch/mips/include/asm/pgtable.h
+++ b/arch/mips/include/asm/pgtable.h
@@ -639,6 +639,11 @@ 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


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2019-12-18 16:23 ` [PATCH v17 05/23] mips: mm: Add p?d_leaf() definitions Steven Price

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