diff --git a/drivers/crypto/sunxi-ss/sun4i-ss-hash.c b/drivers/crypto/sunxi-ss/sun4i-ss-hash.c
index 0c2efc88bc0a..685de5b6ab17 100644
--- a/drivers/crypto/sunxi-ss/sun4i-ss-hash.c
+++ b/drivers/crypto/sunxi-ss/sun4i-ss-hash.c
@@ -384,11 +384,14 @@ hash_final:
 			writesl(ss->base + SS_RXFIFO, op->buf, nwait);
 			op->byte_count += 4 * nwait;
 		}
-		nbw = op->len - 4 * nwait;
-		wb = *(u32 *)(op->buf + nwait * 4);
-		wb &= (0xFFFFFFFF >> (4 - nbw) * 8);
 
-		op->byte_count += nbw;
+		nbw = op->len - 4 * nwait;
+		if (nbw) {
+			wb = *(u32 *)(op->buf + nwait * 4);
+			wb &= GENMASK((nbw * 8) - 1, 0);
+
+			op->byte_count += nbw;
+		}
 	}
 
 	/* write the remaining bytes of the nbw buffer */