Le Thu, Mar 03, 2022 at 02:21:37PM +0000, John Keeping a écrit :

On Wed, Mar 02, 2022 at 09:11:01PM +0000, Corentin Labbe wrote:

quoted

The hardware does not handle 0 size length request, let's add a
fallback.
Furthermore fallback will be used for all unaligned case the hardware
cannot handle.

Fixes: ce0183cb6464b ("crypto: rockchip - switch to skcipher API")
Signed-off-by: Corentin Labbe <clabbe@baylibre.com>
---
 drivers/crypto/rockchip/rk3288_crypto.h       |  2 +
 .../crypto/rockchip/rk3288_crypto_skcipher.c  | 97 ++++++++++++++++---
 2 files changed, 86 insertions(+), 13 deletions(-)

diff --git a/drivers/crypto/rockchip/rk3288_crypto.h b/drivers/crypto/rockchip/rk3288_crypto.h
index c919d9a43a08..8b1e15d8ddc6 100644
--- a/drivers/crypto/rockchip/rk3288_crypto.h
+++ b/drivers/crypto/rockchip/rk3288_crypto.h

@@ -246,10 +246,12 @@ struct rk_cipher_ctx {
 	struct rk_crypto_info		*dev;
 	unsigned int			keylen;
 	u8				iv[AES_BLOCK_SIZE];
+	struct crypto_skcipher *fallback_tfm;
 };
 
 struct rk_cipher_rctx {
 	u32				mode;
+	struct skcipher_request fallback_req;   // keep at the end
 };
 
 enum alg_type {

diff --git a/drivers/crypto/rockchip/rk3288_crypto_skcipher.c b/drivers/crypto/rockchip/rk3288_crypto_skcipher.c
index bbd0bf52bf07..bf9d398cc54c 100644
--- a/drivers/crypto/rockchip/rk3288_crypto_skcipher.c
+++ b/drivers/crypto/rockchip/rk3288_crypto_skcipher.c

@@ -13,6 +13,63 @@
 
 #define RK_CRYPTO_DEC			BIT(0)
 
+static int rk_cipher_need_fallback(struct skcipher_request *req)
+{
+	struct scatterlist *sgs, *sgd;
+
+	if (!req->cryptlen)
+		return true;
+
+	sgs = req->src;
+	while (sgs) {
+		if (!IS_ALIGNED(sgs->offset, sizeof(u32))) {
+			return true;
+		}
+		if (sgs->length % 16) {

Can this be relaxed to check for alignment to 4 rather than 16?  That's
the requirement for programming the registers.

No we cannot, the hardware could operate only one SG at a time, and the cipher operation need to be complete, so the length should be a multiple of AES_BLOCK_SIZE.
The original driver already have this size check.
But for DES/3DES this check is bad and should be 8, so a fix is needed anyway.

But I think this check is wrong in general as it doesn't account for
cryptlen; with fscrypt I'm seeing sgs->length == 255 but cryptlen == 16
so the hardware can be used but at the moment the fallback path is
triggered.

Yes, I need to check min(sg->length, cryptlen_remaining) instead.
I will fix that.

Thanks.

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