We are running a survey to help us improve the experience for all of our members. If you see the survey appear, please take the time to tell us about your experience if you can.
what is the overhead in clock cycles for context switching inside the non-secured (non-secured thread and non-secured thread)
what is the overhead in clock cycles for context switching from the non-secured thread to secured thread ?
Is the answer different between M33 to M23?
You should be more specific what you mean with "context switch". In an OS a "context switch" means for example to save/restore registers, change the MMU/MPU and so on.
Sorry for not clarifying. I do mean context switch of two OS threads .
i.e if I have two threads which were created in the non-secured world, what is the overhead in clock cycle when the context switch between them occurs?
also, if I have two threads, one was created in a secured world and one in a non-secured world, what is the overhead in clock cycle when the context switch between them occurs?
Y.o.o said:orry for not clarifying. I do mean context switch of two OS threads .
Depends on the OS. Better ask in the forum for the OS you are using.
I am familiar with the overhead for regular OS context switching. I was wondering what is the TrustZone additional overhead since it introduce additional secure non-secure switching. My question is regarding the ARM v8 architecture and not os-dependent.
The Cortex-M23 TRM says: "branch And exchange Non-secure BXNS <Rm> 4"