[PATCH v4 4/4] MIPS: mm: add page valid judgement in function pte_modify

[Bibo Mao]

If original PTE has _PAGE_ACCESSED bit set, and new pte has no
_PAGE_NO_READ bit set, we can add _PAGE_SILENT_READ bit to enable
page valid bit.

Signed-off-by: Bibo Mao <maobibo@xxxxxxxxxxx>
---
 arch/mips/include/asm/pgtable.h | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/arch/mips/include/asm/pgtable.h b/arch/mips/include/asm/pgtable.h
index 755d534..4f6eb56 100644
--- a/arch/mips/include/asm/pgtable.h
+++ b/arch/mips/include/asm/pgtable.h
@@ -509,8 +509,11 @@ static inline pte_t pte_modify(pte_t pte, pgprot_t newprot)
 #else
 static inline pte_t pte_modify(pte_t pte, pgprot_t newprot)
 {
-	return __pte((pte_val(pte) & _PAGE_CHG_MASK) |
-		     (pgprot_val(newprot) & ~_PAGE_CHG_MASK));
+	pte_val(pte) &= _PAGE_CHG_MASK;
+	pte_val(pte) |= pgprot_val(newprot) & ~_PAGE_CHG_MASK;
+	if ((pte_val(pte) & _PAGE_ACCESSED) && !(pte_val(pte) & _PAGE_NO_READ))
+		pte_val(pte) |= _PAGE_SILENT_READ;
+	return pte;
 }
 #endif
 
-- 
1.8.3.1