[PATCH v6 4/4] MIPS: mm: add page valid judgement in function pte_modify

From: Bibo Mao
Date: Sun May 24 2020 - 22:53:30 EST


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 0743087..dfe79f4 100644
--- a/arch/mips/include/asm/pgtable.h
+++ b/arch/mips/include/asm/pgtable.h
@@ -529,8 +529,11 @@ 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