[PATCH] drivers/mmc/rpmb.c: Fix driver routing memory alignment with tmp buffer

[PATCH] drivers/mmc/rpmb.c: Fix driver routing memory alignment with tmp buffer

[Timothée Cercueil]

From: litchipi <litchi.pi@protonmail.com>

Fix mmc_rpmb_route_frames() implementation to comply with most MMC
drivers that expect some alignment of MMC data frames in memory.

When called from drivers/tee/optee/rpmb.c, the address passed is not
aligned properly. OP-TEE OS inserts a 6-byte header before a raw RPMB
frame which makes RPMB data buffer not 32bit aligned. To prevent breaking
ABI with OPTEE-OS RPC memrefs, allocate a temporary buffer to copy the
data into an aligned memory.

Many RPMB drivers implicitly expect 32bit alignment of the eMMC frame
including arm_pl180_mmci.c, sandbox_mmc.c and stm32_sdmmc2.c

Signed-off-by: Timothée Cercueil <timothee.cercueil@st.com>
Signed-off-by: litchipi <litchi.pi@protonmail.com>
Change-Id: Iec7554cf6be1219e2d80eb7b45d8d60531c9a7d6
Signed-off-by: Timothée Cercueil <litchi.pi@protonmail.com>
---
 drivers/mmc/rpmb.c | 18 ++++++++++++++++--
 1 file changed, 16 insertions(+), 2 deletions(-)

diff --git a/drivers/mmc/rpmb.c b/drivers/mmc/rpmb.c
index ea7e506666..b68d98573c 100644
--- a/drivers/mmc/rpmb.c
+++ b/drivers/mmc/rpmb.c
@@ -480,10 +480,24 @@ int mmc_rpmb_route_frames(struct mmc *mmc, void *req, unsigned long reqlen,
 	 * and possibly just delay an eventual error which will be harder
 	 * to track down.
 	 */
+	void *rpmb_data = NULL;
+	int ret;

 	if (reqlen % sizeof(struct s_rpmb) || rsplen % sizeof(struct s_rpmb))
 		return -EINVAL;

-	return rpmb_route_frames(mmc, req, reqlen / sizeof(struct s_rpmb),
-				 rsp, rsplen / sizeof(struct s_rpmb));
+	if (!IS_ALIGNED((uintptr_t)req, ARCH_DMA_MINALIGN)) {
+		/* Memory alignment is required by MMC driver */
+		rpmb_data = malloc(reqlen);
+		if (!rpmb_data)
+			return -ENOMEM;
+
+		memcpy(rpmb_data, req, reqlen);
+		req = rpmb_data;
+	}
+
+	ret = rpmb_route_frames(mmc, req, reqlen / sizeof(struct s_rpmb),
+				rsp, rsplen / sizeof(struct s_rpmb));
+	free(rpmb_data);
+	return ret;
 }
--
2.17.1

Re: [PATCH] drivers/mmc/rpmb.c: Fix driver routing memory alignment with tmp buffer

[Jaehoon Chung]

Hi Timorthee,

On 6/15/21 4:29 PM, Timothée Cercueil wrote:
> From: litchipi <litchi.pi@protonmail.com>
> 

Could you change to subject as "mmc: rpmb: fix ...."?

> Fix mmc_rpmb_route_frames() implementation to comply with most MMC
> drivers that expect some alignment of MMC data frames in memory.
> 
> When called from drivers/tee/optee/rpmb.c, the address passed is not
> aligned properly. OP-TEE OS inserts a 6-byte header before a raw RPMB
> frame which makes RPMB data buffer not 32bit aligned. To prevent breaking
> ABI with OPTEE-OS RPC memrefs, allocate a temporary buffer to copy the
> data into an aligned memory.
> 
> Many RPMB drivers implicitly expect 32bit alignment of the eMMC frame
> including arm_pl180_mmci.c, sandbox_mmc.c and stm32_sdmmc2.c
> 
> Signed-off-by: Timothée Cercueil <timothee.cercueil@st.com>
> Signed-off-by: litchipi <litchi.pi@protonmail.com>
> Change-Id: Iec7554cf6be1219e2d80eb7b45d8d60531c9a7d6

Remove Change-Id.

Best Regards,
Jaehoon Chung

> Signed-off-by: Timothée Cercueil <litchi.pi@protonmail.com>
> ---
>  drivers/mmc/rpmb.c | 18 ++++++++++++++++--
>  1 file changed, 16 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/mmc/rpmb.c b/drivers/mmc/rpmb.c
> index ea7e506666..b68d98573c 100644
> --- a/drivers/mmc/rpmb.c
> +++ b/drivers/mmc/rpmb.c
> @@ -480,10 +480,24 @@ int mmc_rpmb_route_frames(struct mmc *mmc, void *req, unsigned long reqlen,
>  	 * and possibly just delay an eventual error which will be harder
>  	 * to track down.
>  	 */
> +	void *rpmb_data = NULL;
> +	int ret;
> 
>  	if (reqlen % sizeof(struct s_rpmb) || rsplen % sizeof(struct s_rpmb))
>  		return -EINVAL;
> 
> -	return rpmb_route_frames(mmc, req, reqlen / sizeof(struct s_rpmb),
> -				 rsp, rsplen / sizeof(struct s_rpmb));
> +	if (!IS_ALIGNED((uintptr_t)req, ARCH_DMA_MINALIGN)) {
> +		/* Memory alignment is required by MMC driver */
> +		rpmb_data = malloc(reqlen);
> +		if (!rpmb_data)
> +			return -ENOMEM;
> +
> +		memcpy(rpmb_data, req, reqlen);
> +		req = rpmb_data;
> +	}
> +
> +	ret = rpmb_route_frames(mmc, req, reqlen / sizeof(struct s_rpmb),
> +				rsp, rsplen / sizeof(struct s_rpmb));
> +	free(rpmb_data);
> +	return ret;
>  }
> --
> 2.17.1
> 
> 
>