The KGUP calls the exit
only in the address space where KGUP is running. The exit receives
control with these characteristics:
- Supervisor state
- APF-authorized
- TCB mode
- Address Space Control mode=primary
- AMODE(31)
- RMODE(ANY)
The exit can change the characteristics during its processing.
However, the exit must return to its caller with the same characteristics
as on entry.