[ 004/100] ARM: 7654/1: Preserve L_PTE_VALID in pte_modify()

[Greg Kroah-Hartman]

3.8-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Catalin Marinas <catalin.marinas@xxxxxxx>

commit 69dde4c52dbac2891b49ff9723d9c84efc5baf6f upstream.

Following commit 26ffd0d4 (ARM: mm: introduce present, faulting entries
for PAGE_NONE), if a page has been mapped as PROT_NONE, the L_PTE_VALID
bit is cleared by the set_pte_ext() code. With LPAE the software and
hardware pte share the same location and subsequent modifications of pte
range (change_protection()) will leave the L_PTE_VALID bit cleared.

This patch adds the L_PTE_VALID bit to the newprot mask in pte_modify().

Signed-off-by: Catalin Marinas <catalin.marinas@xxxxxxx>
Reported-by: Subash Patel <subash.rp@xxxxxxxxxxx>
Tested-by: Subash Patel <subash.rp@xxxxxxxxxxx>
Acked-by: Will Deacon <will.deacon@xxxxxxx>
Signed-off-by: Russell King <rmk+kernel@xxxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
 arch/arm/include/asm/pgtable.h |    3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

--- a/arch/arm/include/asm/pgtable.h
+++ b/arch/arm/include/asm/pgtable.h
@@ -240,7 +240,8 @@ static inline pte_t pte_mkspecial(pte_t
 
 static inline pte_t pte_modify(pte_t pte, pgprot_t newprot)
 {
-	const pteval_t mask = L_PTE_XN | L_PTE_RDONLY | L_PTE_USER | L_PTE_NONE;
+	const pteval_t mask = L_PTE_XN | L_PTE_RDONLY | L_PTE_USER |
+		L_PTE_NONE | L_PTE_VALID;
 	pte_val(pte) = (pte_val(pte) & ~mask) | (pgprot_val(newprot) & mask);
 	return pte;
 }


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