Environmental requirements

The system services exit interface exits are called in the same environment in which the z/OS XML parser was invoked. This means the following:
Minimum authorization
any state and any PSW key
Dispatchable unit mode
Task or SRB
Cross memory mode
Any PASN, any HASN, any SASN
AMODE
31-bit (64-bit)
ASC mode
primary
Interrupt status
enabled for I/O and external interrupts
Locks
no locks held
Control parameters
Control parameters and all data areas the parameter list points to are addressable from the current primary address space.