Ultra96 Shutdown Routine

Hi all,
I have an ULTRA96 and I can turn it off (Linux shut down + chip power down) by pressing a button.
In ULTRA96 schematic I can see interrupt from the push button connected to MIO34_POWER_KILL_B. MIO34 is accessible by the PMU.

I am assuming that this interrupt will active something like XPm_SystemShutdown or XPm_SelfSuspend from (but I am not sure):

Are these functions executed by the PMU, APU or RPU?
I was was wondering how does the Ultra96 Shutdown Routine happen.

I have a push button interrupt controller connected to PS_MIO in a different board.
I want to power off linux and then power down everything else on the Zynq chip.

Do you have any pointers?