Hi,

Looks like another non-secure thread with higher priority could not access secure service since the secure context belongs to previous ongoing non-secure thread and tz_context is not proposed?

/Ken

From: TF-M tf-m-bounces@lists.trustedfirmware.org On Behalf Of Reinhard Keil via TF-M Sent: Thursday, April 2, 2020 9:52 PM To: DeMars, Alan ademars@ti.com; tf-m@lists.trustedfirmware.org Cc: nd nd@arm.com Subject: Re: [TF-M] Multi-threaded single-scheduler model proposal

Alan,

"I was afraid that this was the proposal. No lower priority NS threads can run while waiting for the secure interrupt. Only higher priority threads that are initiated by a NS interrupt can run."

You are correct, scheduling of lower priority NS threads would be not possible. This is definitely a shortcoming of the solution.

May I ask: how long does a hardware crypto operation take? What time could be used for low priority NS thread execution?

Reinhard