/* Returns the segment size indicator for a user address */

@@ -534,11 +544,17 @@ static inline int user_segment_size(unsigned long addr)
 static inline unsigned long get_vsid(unsigned long context, unsigned long ea,
 				     int ssize)
 {
-	if (ssize == MMU_SEGSIZE_256M)
-		return vsid_scramble((context << USER_ESID_BITS)
-				     | (ea >> SID_SHIFT), 256M);
-	return vsid_scramble((context << USER_ESID_BITS_1T)
-			     | (ea >> SID_SHIFT_1T), 1T);
+	unsigned long proto_vsid;
+	if (ssize == MMU_SEGSIZE_256M) {
+		proto_vsid = ((context << USER_ESID_BITS) |(ea >> SID_SHIFT));
+		/* truncate this to 37 bits */
+		proto_vsid &= (1UL << (CONTEXT_BITS + USER_ESID_BITS)) - 1;
+		return vsid_scramble(proto_vsid, 256M);
+	}
+	proto_vsid = ((context << USER_ESID_BITS_1T) | (ea >> SID_SHIFT_1T));
+	/* truncate this to 25 bits */
+	proto_vsid &= (1UL << (CONTEXT_BITS + USER_ESID_BITS_1T)) - 1;
+	return vsid_scramble( proto_vsid, 1T);
 }