I know TZEN is used to enable TrustZone. At first, this made sense, but now I think about the MCU implementing the Security/TrustZone, and it sounds strange that TrustZone can be disabled. So my question is, what does it really do ? Does it really somehow disable (power down?, clock gated?) the TrustZone related things (SAU, GTZC etc.) ? so there is really a signal somewhere inside the die that enables/disables this. Or, is the TrustZone in the core always enabled and TZEN just reconfigures things so everything runs like a secure binary or maybe nothing generates a security fault ?
