[PATCH] optee/rpmb.c: Fix driver routing memory alignment using a temporary buffer

[Timothée Cercueil]

From: Timothée Cercueil <timothee.cercueil at st.com>

OP-TEE OS inserts a 6-byte header before a raw RPMB frame which makes
RPMB data buffer not 32bit aligned. Many RPMB drivers implicitly expect
32bit alignment of the eMMC frame including arm_pl180_mmci.c, sandbox_mmc.c
and stm32_sdmmc2.c

To prevent breaking ABI with OPTEE-OS RPC memrefs, allocate a temporary
buffer to copy the data into an aligned memory.

Signed-off-by: Timothée Cercueil <timothee.cercueil at st.com>
Change-Id: Id78d638851a666a35af907ca8de71dae00946457
Signed-off-by: Timothée Cercueil <litchi.pi at protonmail.com>
---
 drivers/tee/optee/rpmb.c | 24 +++++++++++++++++++++---
 1 file changed, 21 insertions(+), 3 deletions(-)

diff --git a/drivers/tee/optee/rpmb.c b/drivers/tee/optee/rpmb.c
index 0804fc963c..4713df711c 100644
--- a/drivers/tee/optee/rpmb.c
+++ b/drivers/tee/optee/rpmb.c
@@ -122,6 +122,10 @@ static u32 rpmb_process_request(struct optee_private *priv, void *req,
 {
 	struct rpmb_req *sreq = req;
 	struct mmc *mmc;
+	void *rpmb_data;
+	void *rpmb_frame_buffer = NULL;
+	size_t rpmb_data_sz;
+	int ret;

 	if (req_size < sizeof(*sreq))
 		return TEE_ERROR_BAD_PARAMETERS;
@@ -131,9 +135,23 @@ static u32 rpmb_process_request(struct optee_private *priv, void *req,
 		mmc = get_mmc(priv, sreq->dev_id);
 		if (!mmc)
 			return TEE_ERROR_ITEM_NOT_FOUND;
-		if (mmc_rpmb_route_frames(mmc, RPMB_REQ_DATA(req),
-					  req_size - sizeof(struct rpmb_req),
-					  rsp, rsp_size))
+
+		rpmb_data = RPMB_REQ_DATA(req);
+		rpmb_data_sz = req_size - sizeof(struct rpmb_req);
+		if (!IS_ALIGNED((uintptr_t)rpmb_data, sizeof(u32))) {
+			/* 32bit data alignment is required by RPMB driver */
+			rpmb_frame_buffer = malloc(rpmb_data_sz);
+			if (!rpmb_frame_buffer)
+				return TEE_ERROR_OUT_OF_MEMORY;
+
+			memcpy(rpmb_frame_buffer, rpmb_data, rpmb_data_sz);
+			rpmb_data = rpmb_frame_buffer;
+		}
+
+		ret = mmc_rpmb_route_frames(mmc, rpmb_data, rpmb_data_sz,
+					    rsp, rsp_size);
+		free(rpmb_frame_buffer);
+		if (ret)
 			return TEE_ERROR_BAD_PARAMETERS;
 		return TEE_SUCCESS;

--
2.17.1