[PATCH v8 07/15] crypto: ti - Separate padding buffer for src and dst

[T Pratham]

Separate the padding buffer, which is allocated in the req ctx, for src
and dst scatterlist to avoid any DMA mapping issues when not doing
inline operations. In such cases, the current code was mapping the same
padding buffer twice which might cause issues. Also move them into
differnt groups in __dma_from_device_group_begin/end() to separate the
cache lines for transports of different directions.

Fixes: 35645ca63caa1 ("crypto: ti - Add support for AES-CTR in DTHEv2 driver")
Signed-off-by: T Pratham <t-pratham@xxxxxx>
---
 drivers/crypto/ti/dthev2-aes.c    | 29 +++++++++++++++++++----------
 drivers/crypto/ti/dthev2-common.h | 14 ++++++++++----
 2 files changed, 29 insertions(+), 14 deletions(-)

diff --git a/drivers/crypto/ti/dthev2-aes.c b/drivers/crypto/ti/dthev2-aes.c
index 5be1bcaeee5ed..83d964e884086 100644
--- a/drivers/crypto/ti/dthev2-aes.c
+++ b/drivers/crypto/ti/dthev2-aes.c
@@ -338,6 +338,9 @@ static int dthe_aes_run(struct crypto_engine *engine, void *areq)
 	int src_mapped_nents;
 	int dst_mapped_nents;
 
+	u8 *src_padding = rctx->src_padding;
+	u8 *dst_padding = rctx->dst_padding;
+
 	bool diff_dst;
 	enum dma_data_direction src_dir, dst_dir;
 
@@ -388,8 +391,8 @@ static int dthe_aes_run(struct crypto_engine *engine, void *areq)
 	sg_init_table(src, src_nents);
 	sg = dthe_copy_sg(src, req->src, req->cryptlen);
 	if (pad_len > 0) {
-		memzero_explicit(rctx->padding, AES_BLOCK_SIZE);
-		sg_set_buf(sg, rctx->padding, pad_len);
+		memzero_explicit(src_padding, AES_BLOCK_SIZE);
+		sg_set_buf(sg, src_padding, pad_len);
 	}
 
 	if (diff_dst) {
@@ -401,8 +404,10 @@ static int dthe_aes_run(struct crypto_engine *engine, void *areq)
 
 		sg_init_table(dst, dst_nents);
 		sg = dthe_copy_sg(dst, req->dst, req->cryptlen);
-		if (pad_len > 0)
-			sg_set_buf(sg, rctx->padding, pad_len);
+		if (pad_len > 0) {
+			memzero_explicit(dst_padding, AES_BLOCK_SIZE);
+			sg_set_buf(sg, dst_padding, pad_len);
+		}
 	} else {
 		dst = src;
 	}
@@ -491,8 +496,10 @@ static int dthe_aes_run(struct crypto_engine *engine, void *areq)
 	dma_unmap_sg(tx_dev, src, src_nents, src_dir);
 
 aes_map_src_err:
-	if (ctx->aes_mode == DTHE_AES_CTR && req->cryptlen % AES_BLOCK_SIZE)
-		memzero_explicit(rctx->padding, AES_BLOCK_SIZE);
+	if (ctx->aes_mode == DTHE_AES_CTR && req->cryptlen % AES_BLOCK_SIZE) {
+		memzero_explicit(rctx->src_padding, AES_BLOCK_SIZE);
+		memzero_explicit(rctx->dst_padding, AES_BLOCK_SIZE);
+	}
 	if (diff_dst)
 		kfree(dst);
 
@@ -880,9 +887,9 @@ static int dthe_aead_run(struct crypto_engine *engine, void *areq)
 	int src_mapped_nents = 0;
 	int dst_mapped_nents = 0;
 
-	u8 *src_assoc_padbuf = rctx->padding;
-	u8 *src_crypt_padbuf = rctx->padding + AES_BLOCK_SIZE;
-	u8 *dst_crypt_padbuf = rctx->padding + AES_BLOCK_SIZE;
+	u8 *src_assoc_padbuf = rctx->aad_padding;
+	u8 *src_crypt_padbuf = rctx->src_padding;
+	u8 *dst_crypt_padbuf = rctx->dst_padding;
 
 	bool diff_dst;
 	enum dma_data_direction aad_dir, src_dir, dst_dir;
@@ -1125,7 +1132,9 @@ static int dthe_aead_run(struct crypto_engine *engine, void *areq)
 		kfree(aad_sg);
 
 aead_prep_aad_err:
-	memzero_explicit(rctx->padding, 2 * AES_BLOCK_SIZE);
+	memzero_explicit(rctx->aad_padding, AES_BLOCK_SIZE);
+	memzero_explicit(rctx->src_padding, AES_BLOCK_SIZE);
+	memzero_explicit(rctx->dst_padding, AES_BLOCK_SIZE);
 
 	if (ret)
 		ret = dthe_aead_do_fallback(req);
diff --git a/drivers/crypto/ti/dthev2-common.h b/drivers/crypto/ti/dthev2-common.h
index e2600447f217a..f6e02f33ef106 100644
--- a/drivers/crypto/ti/dthev2-common.h
+++ b/drivers/crypto/ti/dthev2-common.h
@@ -109,15 +109,21 @@ struct dthe_tfm_ctx {
 /**
  * struct dthe_aes_req_ctx - AES engine req ctx struct
  * @enc: flag indicating encryption or decryption operation
- * @padding: padding buffer for handling unaligned data
+ * @src_padding: padding buffer for handling unaligned data in src
+ * @aad_padding: padding buffer for handling unaligned data in aad
+ * @dst_padding: padding buffer for handling unaligned data in dst
  * @aes_compl: Completion variable for use in manual completion in case of DMA callback failure
  * @dev_data: Device data struct pointer
  */
 struct dthe_aes_req_ctx {
 	int enc;
-	__dma_from_device_group_begin();
-	u8 padding[2 * AES_BLOCK_SIZE];
-	__dma_from_device_group_end();
+	__dma_from_device_group_begin(to_device);
+	u8 src_padding[AES_BLOCK_SIZE];
+	u8 aad_padding[AES_BLOCK_SIZE];
+	__dma_from_device_group_end(to_device);
+	__dma_from_device_group_begin(from_device);
+	u8 dst_padding[AES_BLOCK_SIZE];
+	__dma_from_device_group_end(from_device);
 	struct completion aes_compl;
 	struct dthe_data *dev_data;
 };
-- 
2.34.1