Hello, experts:
My platform has a Cortex-A9 MPCore CPU, It supports trustzone tech.
I tried to change NSACR.TL bit, but It needs to change in the secure state.
I checked NSACR value in non-secure state and NSACR value that I changed is changed aperiodically.
For example print value;
nsacr : 0x00000000nsacr : 0x00000000nsacr : 0x00000000
....nsacr : 0x00200000nsacr : 0x00200000nsacr : 0x00200000....
Is NSACR.TL changed correctly?
Why NSACR value changed aperiodcially?
Best wishes,
AFAIK runs Linux in normal world (non-secure). The bootloader (U-Boot or even the first stage boot-loader) will switch to non-secure.
If you want to change NSACR you have to run at least a secure monitor.But if you have software running in privileged mode, you can check the SCR.NS (MRC p15, 0, <Rt>, c1, c1, 0 ; Read SCR into Rt).