diff --git a/arch/mips/mm/init.c b/arch/mips/mm/init.c
index 09d91505b90c..5240432e6d1d 100644
--- a/arch/mips/mm/init.c
+++ b/arch/mips/mm/init.c
@@ -8,6 +8,7 @@
  * Kevin D. Kissell, kevink@mips.com and Carsten Langgaard, carstenl@mips.com
  * Copyright (C) 2000 MIPS Technologies, Inc.  All rights reserved.
  */
+#include <linux/bug.h>
 #include <linux/init.h>
 #include <linux/module.h>
 #include <linux/signal.h>
@@ -132,6 +133,8 @@ void *kmap_coherent(struct page *page, unsigned long addr)
 	pte_t pte;
 	int tlbidx;
 
+	BUG_ON(Page_dcache_dirty(page));
+
 	inc_preempt_count();
 	idx = (addr >> PAGE_SHIFT) & (FIX_N_COLOURS - 1);
 #ifdef CONFIG_MIPS_MT_SMTC
@@ -208,7 +211,7 @@ void copy_user_highpage(struct page *to, struct page *from,
 	void *vfrom, *vto;
 
 	vto = kmap_atomic(to, KM_USER1);
-	if (cpu_has_dc_aliases) {
+	if (cpu_has_dc_aliases && !Page_dcache_dirty(from)) {
 		vfrom = kmap_coherent(from, vaddr);
 		copy_page(vto, vfrom);
 		kunmap_coherent();