What will I get if I operate p15 to switch to TZ mode when I'm right in TZ mode.

Will SMC instruction directly cause the transition via monitor mode, or I should use a switch routine to handle the smi_hdler exception to finish the transition?

Will SMC instruction directly cause the transition via monitor mode, or I should use a switch routine to handle the smi_hdler exception to finish the transition?

You'll need some monitor mode software to handle the exception - there's no automatic hardware support (i.e. it behaves like any other svc software "interrupt").

HTH,
Pete

Thank u very much~