arm64: Make !dirty ptes read-only
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>
Cc: <stable@vger.kernel.org>
diff --git a/arch/arm64/include/asm/pgtable.h b/arch/arm64/include/asm/pgtable.h
index 8960239..937ae206 100644
--- a/arch/arm64/include/asm/pgtable.h
+++ b/arch/arm64/include/asm/pgtable.h
@@ -159,6 +159,8 @@
{
if (pte_present_exec_user(pte))
__sync_icache_dcache(pte, addr);
+ if (!pte_dirty(pte))
+ pte = pte_wrprotect(pte);
set_pte(ptep, pte);
}