Re: [PATCH 1/2] remoteproc: mediatek: Make sure IPI buffer fits in L2TCM

Mathieu Poirier
2024-03-21T15:25:35Z

Good day,

On Thu, Mar 21, 2024 at 09:46:13AM +0100, AngeloGioacchino Del Regno wrote:
> The IPI buffer location is read from the firmware that we load to the
> System Companion Processor, and it's not granted that both the SRAM
> (L2TCM) size that is defined in the devicetree node is large enough
> for that, and while this is especially true for multi-core SCP, it's
> still useful to check on single-core variants as well.
>
> Failing to perform this check may make this driver perform R/W
> oeprations out of the L2TCM boundary, resulting (at best) in a

s/oeprations/operations

I will fix that when I apply the patch.

> kernel panic.
>
> To fix that, check that the IPI buffer fits, otherwise return a
> failure and refuse to boot the relevant SCP core (or the SCP at
> all, if this is single core).
>
> Fixes: 3efa0ea743b7 ("remoteproc/mediatek: read IPI buffer offset from FW")
> Signed-off-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
> ---
> drivers/remoteproc/mtk_scp.c | 10 +++++++++-
> 1 file changed, 9 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/remoteproc/mtk_scp.c b/drivers/remoteproc/mtk_scp.c
> index a35409eda0cf..67518291a8ad 100644
> --- a/drivers/remoteproc/mtk_scp.c
> +++ b/drivers/remoteproc/mtk_scp.c
> @@ -132,7 +132,7 @@ static int scp_elf_read_ipi_buf_addr(struct mtk_scp *scp,
> static int scp_ipi_init(struct mtk_scp *scp, const struct firmware *fw)
> {
> int ret;
> - size_t offset;
> + size_t buf_sz, offset;
>
> /* read the ipi buf addr from FW itself first */
> ret = scp_elf_read_ipi_buf_addr(scp, fw, &offset);
> @@ -144,6 +144,14 @@ static int scp_ipi_init(struct mtk_scp *scp, const struct firmware *fw)
> }
> dev_info(scp->dev, "IPI buf addr %#010zx\n", offset);
>
> + /* Make sure IPI buffer fits in the L2TCM range assigned to this core */
> + buf_sz = sizeof(*scp->recv_buf) + sizeof(*scp->send_buf);
> +
> + if (scp->sram_size < buf_sz + offset) {
> + dev_err(scp->dev, "IPI buffer does not fit in SRAM.\n");
> + return -EOVERFLOW;
> + }
> +
> scp->recv_buf = (struct mtk_share_obj __iomem *)
> (scp->sram_base + offset);
> scp->send_buf = (struct mtk_share_obj __iomem *)
> --
> 2.44.0
>