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

Greg Kroah-Hartman
2013-01-09T20:36:52Z

From: Catalin Marinas <catalin.marinas@arm.com>

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@arm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
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);
}