[TF-M] NS application privilege mode

Hello,

May a non-secure TFM user application stay in the privilege mode after start-up? It's needed, as some system registers are accessible only in the privilege mode. Asking, because the TFM NS Musca start-up code is switching to the unprivileged mode from very beginning: MRS R0, control ; Get control value ORR R0, R0, #1 ; Select switch to unprivilage mode ORR R0, R0, #2 ; Select switch to PSP MSR control, R0 Hope, it is not mandatory.

Thanks, Andrej Butok