Any program can issue a PC instruction provided the program is running in either primary or AR ASC mode. When a program issues a PC instruction, the system invokes the requested PC routine providing the service provider has made the PC routine available to the calling program's address space. In addition, if the calling program is running in problem state, it must also have a PSW-key mask (PKM) that the service provider has authorized to invoke the PC routine. The PC routine, or other routines that it invokes, performs the service the caller desires.

The service provider is responsible for defining the level of authorization problem programs need to invoke a PC routine. The service provider defines the level of authorization for each PC routine by specifying the PKM that a problem state program must have to invoke the PC routine. If the problem program's PKM agrees with the service provider's specification, the system allows the problem program to invoke the PC routine. Otherwise, the PC instruction causes a program interrupt (privileged operation exception).