linux-kernel - [PATCH v2 10/19] crypto: sun8i-ss: do not zeroize all pad

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Message-Id: <20220502201929.843194-11-clabbe@baylibre.com>
Date:   Mon,  2 May 2022 20:19:20 +0000
From:   Corentin Labbe <clabbe@...libre.com>
To:     herbert@...dor.apana.org.au, jernej.skrabec@...il.com,
        samuel@...lland.org, wens@...e.org
Cc:     linux-arm-kernel@...ts.infradead.org, linux-crypto@...r.kernel.org,
        linux-kernel@...r.kernel.org, linux-sunxi@...ts.linux.dev,
        Corentin Labbe <clabbe@...libre.com>
Subject: [PATCH v2 10/19] crypto: sun8i-ss: do not zeroize all pad

Instead of memset all pad buffer, it is faster to only put 0 where
needed.

Signed-off-by: Corentin Labbe <clabbe@...libre.com>
---
 drivers/crypto/allwinner/sun8i-ss/sun8i-ss-hash.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/drivers/crypto/allwinner/sun8i-ss/sun8i-ss-hash.c b/drivers/crypto/allwinner/sun8i-ss/sun8i-ss-hash.c
index 9582ac450d08..53e5bfb99c93 100644
--- a/drivers/crypto/allwinner/sun8i-ss/sun8i-ss-hash.c
+++ b/drivers/crypto/allwinner/sun8i-ss/sun8i-ss-hash.c
@@ -319,7 +319,7 @@ int sun8i_ss_hash_run(struct crypto_engine *engine, void *breq)
 	unsigned int len;
 	u64 fill, min_fill, byte_count;
 	void *pad, *result;
-	int j, i, todo;
+	int j, i, k, todo;
 	__be64 *bebits;
 	__le64 *lebits;
 	dma_addr_t addr_res, addr_pad;
@@ -334,7 +334,6 @@ int sun8i_ss_hash_run(struct crypto_engine *engine, void *breq)
 
 	result = ss->flows[rctx->flow].result;
 	pad = ss->flows[rctx->flow].pad;
-	memset(pad, 0, algt->alg.hash.halg.base.cra_blocksize * 2);
 	bf = (__le32 *)pad;
 
 	for (i = 0; i < MAX_SG; i++) {
@@ -395,7 +394,10 @@ int sun8i_ss_hash_run(struct crypto_engine *engine, void *breq)
 	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:
-- 
2.35.1