From b4b264f3e98d138dd4ceea5e4ae2f7c8dc4d9df6 Mon Sep 17 00:00:00 2001
From: Alan Cox <alc@FreeBSD.org>
Date: Sat, 23 May 2009 18:33:22 +0000
Subject: [PATCH] When a page is mapped for write access on a read fault, the
 PTE should be configured to trap on a write access unless *all* of the page's
 dirty bits are set.

---
 sys/mips/mips/pmap.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/sys/mips/mips/pmap.c b/sys/mips/mips/pmap.c
index 2188c369561..c3d6060a35e 100644
--- a/sys/mips/mips/pmap.c
+++ b/sys/mips/mips/pmap.c
@@ -3116,7 +3116,8 @@ init_pte_prot(vm_offset_t va, vm_page_t m, vm_prot_t prot)
 			 */
 			rw = PTE_RWPAGE;
 			vm_page_dirty(m);
-		} else if ((m->md.pv_flags & PV_TABLE_MOD) || m->dirty)
+		} else if ((m->md.pv_flags & PV_TABLE_MOD) ||
+		    m->dirty == VM_PAGE_BITS_ALL)
 			rw = PTE_RWPAGE;
 		else
 			rw = PTE_CWPAGE;