linux-kernel - [PATCH v6 4/4] MIPS: mm: add page valid judgement in function pte

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Date:   Mon, 25 May 2020 10:52:40 +0800
From:   Bibo Mao <maobibo@...ngson.cn>
To:     Thomas Bogendoerfer <tsbogend@...ha.franken.de>,
        Jiaxun Yang <jiaxun.yang@...goat.com>,
        Huacai Chen <chenhc@...ote.com>,
        Andrew Morton <akpm@...ux-foundation.org>,
        Paul Burton <paulburton@...nel.org>,
        Dmitry Korotin <dkorotin@...ecomp.com>,
        Philippe Mathieu-Daudé <f4bug@...at.org>,
        Stafford Horne <shorne@...il.com>,
        Steven Price <steven.price@....com>,
        Anshuman Khandual <anshuman.khandual@....com>
Cc:     linux-mips@...r.kernel.org, linux-kernel@...r.kernel.org,
        Mike Rapoport <rppt@...ux.ibm.com>,
        Sergei Shtylyov <sergei.shtylyov@...entembedded.com>,
        "Maciej W. Rozycki" <macro@....com>, linux-mm@...ck.org,
        David Hildenbrand <david@...hat.com>
Subject: [PATCH v6 4/4] MIPS: mm: add page valid judgement in function pte_modify

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@...ngson.cn>
---
 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