crypto: sun8i-ss - Add function for handling hash padding

Move all padding work to a dedicated function.
Signed-off-by: Corentin Labbe <clabbe@baylibre.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

drivers/crypto/allwinner/sun8i-ss/sun8i-ss-hash.c

@@ -328,6 +328,64 @@ int sun8i_ss_hash_digest(struct ahash_request *areq)
 	return crypto_transfer_hash_request_to_engine(engine, areq);
 }
 
+static u64 hash_pad(__le32 *buf, unsigned int bufsize, u64 padi, u64 byte_count, bool le, int bs)
+{
+	u64 fill, min_fill, j, k;
+	__be64 *bebits;
+	__le64 *lebits;
+
+	j = padi;
+	buf[j++] = cpu_to_le32(0x80);
+
+	if (bs == 64) {
+		fill = 64 - (byte_count % 64);
+		min_fill = 2 * sizeof(u32) + sizeof(u32);
+	} else {
+		fill = 128 - (byte_count % 128);
+		min_fill = 4 * sizeof(u32) + sizeof(u32);
+	}
+
+	if (fill < min_fill)
+		fill += bs;
+
+	k = j;
+	j += (fill - min_fill) / sizeof(u32);
+	if (j * 4 > bufsize) {
+		pr_err("%s OVERFLOW %llu\n", __func__, j);
+		return 0;
+	}
+	for (; k < j; k++)
+		buf[k] = 0;
+
+	if (le) {
+		/* MD5 */
+		lebits = (__le64 *)&buf[j];
+		*lebits = cpu_to_le64(byte_count << 3);
+		j += 2;
+	} else {
+		if (bs == 64) {
+			/* sha1 sha224 sha256 */
+			bebits = (__be64 *)&buf[j];
+			*bebits = cpu_to_be64(byte_count << 3);
+			j += 2;
+		} else {
+			/* sha384 sha512*/
+			bebits = (__be64 *)&buf[j];
+			*bebits = cpu_to_be64(byte_count >> 61);
+			j += 2;
+			bebits = (__be64 *)&buf[j];
+			*bebits = cpu_to_be64(byte_count << 3);
+			j += 2;
+		}
+	}
+	if (j * 4 > bufsize) {
+		pr_err("%s OVERFLOW %llu\n", __func__, j);
+		return 0;
+	}
+
+	return j;
+}
+
 /* sun8i_ss_hash_run - run an ahash request
  * Send the data of the request to the SS along with an extra SG with padding
  */
@@ -342,11 +400,9 @@ int sun8i_ss_hash_run(struct crypto_engine *engine, void *breq)
 	struct scatterlist *sg;
 	int nr_sgs, err, digestsize;
 	unsigned int len;
-	u64 fill, min_fill, byte_count;
+	u64 byte_count;
 	void *pad, *result;
 	int j, i, k, todo;
-	__be64 *bebits;
-	__le64 *lebits;
 	dma_addr_t addr_res, addr_pad;
 	__le32 *bf;
 
@@ -421,33 +477,20 @@ int sun8i_ss_hash_run(struct crypto_engine *engine, void *breq)
 		i--;
 
 	byte_count = areq->nbytes;
-	bf[j++] = cpu_to_le32(0x80);
-
-	fill = 64 - (byte_count % 64);
-	min_fill = 3 * sizeof(u32);
-
-	if (fill < min_fill)
-		fill += 64;
-
-	k = j;
-	j += (fill - min_fill) / sizeof(u32);
-	for (; k < j; k++)
-		bf[k] = 0;
-
 	switch (algt->ss_algo_id) {
 	case SS_ID_HASH_MD5:
-		lebits = (__le64 *)&bf[j];
-		*lebits = cpu_to_le64(byte_count << 3);
-		j += 2;
+		j = hash_pad(bf, 4096, j, byte_count, true, bs);
 		break;
 	case SS_ID_HASH_SHA1:
 	case SS_ID_HASH_SHA224:
 	case SS_ID_HASH_SHA256:
-		bebits = (__be64 *)&bf[j];
-		*bebits = cpu_to_be64(byte_count << 3);
-		j += 2;
+		j = hash_pad(bf, 4096, j, byte_count, false, bs);
 		break;
 	}
+	if (!j) {
+		err = -EINVAL;
+		goto theend;
+	}
 
 	addr_pad = dma_map_single(ss->dev, pad, j * 4, DMA_TO_DEVICE);
 	if (dma_mapping_error(ss->dev, addr_pad)) {