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Is preemption possible after state change to non-secure using BLXNS?

dnjsdnwja

In ARMv8-M, there is BLXNS instruction to call a non-secure procedure from secure world, and the architectural reference manual mentions that it makes IPSR to 1.

Then, does it mean that the priority becomes -4 as the exception number (IPSR) is the same as that of Reset?

In other words, does it mean that no preemption due to interrupt is possible after BLXNS to the non-secure world until returning back to the secure world?

If that's true, are there any method to make preemption possible, for example by lowering the priority of Reset Exception just like how setting PRIMASK_NS and AIRCR.PRIS flags turn PRIMASK boosting priority from 0 to 0x80?

Thanks for any help!

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