[ 009/123] arm64: Make !dirty ptes read-only

[Greg Kroah-Hartman]

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

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

From: Catalin Marinas <catalin.marinas@xxxxxxx>

commit 33eaa58f854770dc9c98411a356c98e3a53edfda upstream.

The AArch64 Linux port relies on the mm code to wrprotect clean ptes.
This however is not the case with newly created ptes and
PAGE_SHARED(_EXEC) is writable but !dirty.

Signed-off-by: Catalin Marinas <catalin.marinas@xxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
 arch/arm64/include/asm/pgtable.h |    2 ++
 1 file changed, 2 insertions(+)

--- a/arch/arm64/include/asm/pgtable.h
+++ b/arch/arm64/include/asm/pgtable.h
@@ -159,6 +159,8 @@ static inline void set_pte_at(struct mm_
 {
 	if (pte_present_exec_user(pte))
 		__sync_icache_dcache(pte, addr);
+	if (!pte_dirty(pte))
+		pte = pte_wrprotect(pte);
 	set_pte(ptep, pte);
 }
 


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