Re: [PATCH v2 1/2] remoteproc: qcom_q6v5_mss: Add modem debug policy support

Bjorn Andersson
2020-07-22T03:56:24Z

On Tue 21 Jul 04:29 PDT 2020, Sibi Sankar wrote:

> Add modem debug policy support which will enable coredumps and live
> debug support when the msadp firmware is present on secure devices.
>
> Signed-off-by: Sibi Sankar <sibis@codeaurora.org>
> ---
>
> v2:
> * Use request_firmware_direct [Bjorn]
> * Use Bjorn's template to show if debug policy is present
> * Add size check to prevent memcpy out of bounds [Bjorn]
>
> drivers/remoteproc/qcom_q6v5_mss.c | 16 +++++++++++++++-
> 1 file changed, 15 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/remoteproc/qcom_q6v5_mss.c b/drivers/remoteproc/qcom_q6v5_mss.c
> index 0b6f260eb5349..49cd16e050533 100644
> --- a/drivers/remoteproc/qcom_q6v5_mss.c
> +++ b/drivers/remoteproc/qcom_q6v5_mss.c
> @@ -189,6 +189,7 @@ struct q6v5 {
> phys_addr_t mba_phys;
> void *mba_region;
> size_t mba_size;
> + size_t dp_size;
>
> phys_addr_t mpss_phys;
> phys_addr_t mpss_reloc;
> @@ -408,6 +409,14 @@ static int q6v5_xfer_mem_ownership(struct q6v5 *qproc, int *current_perm,
> static int q6v5_load(struct rproc *rproc, const struct firmware *fw)
> {
> struct q6v5 *qproc = rproc->priv;
> + const struct firmware *dp_fw;
> +
> + if (!request_firmware_direct(&dp_fw, "msadp", qproc->dev) && fw->size <= SZ_1M &&
> + (SZ_1M + dp_fw->size) <= qproc->mba_size) {
> + memcpy(qproc->mba_region + SZ_1M, dp_fw->data, dp_fw->size);
> + qproc->dp_size = dp_fw->size;
> + release_firmware(dp_fw);

If request_firmware_direct() succeeds, but return a firmware blob bigger
than mba_size - SZ_1M you won't get here and will end up leaking dp_fw.

Additionally, there really isn't a need for requesting the firmware in
the first place if fw->size > SZ_1M.

So I think it's better if you break this out in it's own function where
you don't need to squeeze everything into one or two conditionals.

Regards,
Bjorn

> + }
>
> memcpy(qproc->mba_region, fw->data, fw->size);
>
> @@ -896,6 +905,10 @@ static int q6v5_mba_load(struct q6v5 *qproc)
> }
>
> writel(qproc->mba_phys, qproc->rmb_base + RMB_MBA_IMAGE_REG);
> + if (qproc->dp_size) {
> + writel(qproc->mba_phys + SZ_1M, qproc->rmb_base + RMB_PMI_CODE_START_REG);
> + writel(qproc->dp_size, qproc->rmb_base + RMB_PMI_CODE_LENGTH_REG);
> + }
>
> ret = q6v5proc_reset(qproc);
> if (ret)
> @@ -1257,7 +1270,8 @@ static int q6v5_start(struct rproc *rproc)
> if (ret)
> return ret;
>
> - dev_info(qproc->dev, "MBA booted, loading mpss\n");
> + dev_info(qproc->dev, "MBA booted with%s debug policy, loading mpss\n",
> + qproc->dp_size ? "" : "out");
>
> ret = q6v5_mpss_load(qproc);
> if (ret)
> --
> The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
> a Linux Foundation Collaborative Project
>