diff --git a/arch/powerpc/mm/mem.c b/arch/powerpc/mm/mem.c
index 2fd57fa48429bd60e0c0605dee812ae9870c41ed..9eac9d46f54b0d8eed5f5c9bb23451d0cfb664f4 100644
--- a/arch/powerpc/mm/mem.c
+++ b/arch/powerpc/mm/mem.c
@@ -239,8 +239,14 @@ static int __init mark_nonram_nosave(void)
 
 static bool zone_limits_final;
 
+/*
+ * The memory zones past TOP_ZONE are managed by generic mm code.
+ * These should be set to zero since that's what every other
+ * architecture does.
+ */
 static unsigned long max_zone_pfns[MAX_NR_ZONES] = {
-	[0 ... MAX_NR_ZONES - 1] = ~0UL
+	[0            ... TOP_ZONE        ] = ~0UL,
+	[TOP_ZONE + 1 ... MAX_NR_ZONES - 1] = 0
 };
 
 /*