[PATCH] mmc: rpmb: Fix driver routing memory alignment with tmp buffer

[litchi.pi]

Hello,
Does anyone have a feedback on that fix ?
I think the location of the fix is important to be discussed too as it needs to be generic but not overlap with existing checks.
Have a nice day,
Timothée Cercueil

‐‐‐‐‐‐‐ Original Message ‐‐‐‐‐‐‐

On Tuesday, June 15th, 2021 at 10:53 AM, Timothée Cercueil <litchi.pi at protonmail.com> wrote:

> From: litchipi litchi.pi at 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 at st.com
>
> Signed-off-by: Timothée Cercueil litchi.pi at protonmail.com
>
> drivers/mmc/rpmb.c | 18 ++++++++++++++++--
>
> 1 file changed, 16 insertions(+), 2 deletions(-)
>
> Changes since v1:
>
> - Fixed the Signed-off-by errors from previous patch.
>
> - This patch follows the subject discussed at: https://lists.denx.de/pipermail/u-boot/2021-June/451687.html
>
> - Changed the commit log 1st line
>
> 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