On Fri, Nov 07, 2025 at 11:20:20AM +0100, Konrad Dybcio wrote:
> On 11/4/25 8:35 AM, Mukesh Ojha wrote:
> > Qualcomm remote processor may rely on Static and Dynamic resources for
> > it to be functional. Static resources are fixed like for example,
> > memory-mapped addresses required by the subsystem and dynamic
> > resources, such as shared memory in DDR etc., are determined at
> > runtime during the boot process.
> >
> > For most of the Qualcomm SoCs, when run with Gunyah or older QHEE
> > hypervisor, all the resources whether it is static or dynamic, is
> > managed by the hypervisor. Dynamic resources if it is present for a
> > remote processor will always be coming from secure world via SMC call
> > while static resources may be present in remote processor firmware
> > binary or it may be coming qcom_scm_pas_get_rsc_table() SMC call along
> > with dynamic resources.
>
> [...]
>
>
> > + /*
> > + * TrustZone can not accept buffer as NULL value as argument Hence,
> > + * we need to pass a input buffer indicating that subsystem firmware
> > + * does not have resource table by filling resource table structure.
> > + */
> > + if (!input_rt)
> > + input_rt_size = sizeof(*rsc);
>
> Would the expected size of the received data ever be any different
> than sizeof(*rsc) anyway?
input_rt_size != 0 and input_rt = NULL as input to this SCM call are
invalid scenario.
Expected input_rt_size would be greater than sizeof(*rsc) if remote
processor firmware will have resource table section.
>
> [...]
>
> > +int qcom_scm_pas_get_rsc_table(struct qcom_scm_pas_context *ctx, void
> > *input_rt,
> > + size_t input_rt_size, void **output_rt,
> > + size_t *output_rt_size)
> > +{
> > + int ret;
> > +
> > + do {
> > + *output_rt = kzalloc(*output_rt_size, GFP_KERNEL);
> > + if (!*output_rt)
> > + return -ENOMEM;
> > +
> > + ret = __qcom_scm_pas_get_rsc_table(ctx->pas_id, input_rt,
> > + input_rt_size, output_rt,
> > + output_rt_size);
> > + if (ret)
> > + kfree(*output_rt);
> > +
> > + } while (ret == -EAGAIN);
>
> This should at the very least be limited to a number of retries
Sure, how about 5 ?
>
> Konrad
--
-Mukesh Ojha
