Computing environment for the CSM API

This section describes the environment where the IVTCSM macro is issued.

Environment

The following requirements are for the caller:

Minimum authorization:: Supervisor state. Any PSW key.
Dispatchable unit mode:: Task or SRB.
Exception: CREATE_POOL and DELETE_POOL requests must be issued in Task Mode.
Cross memory mode:: Any PASN, any HASN, any SASN.
CREATE_POOL and DELETE_POOL requests are PASN=HASN=SASN only.
AMODE:: 31-bit.
ASC mode:: Primary.
Interrupt status:: Enabled for I/O and external interrupts.
Locks:: No locks can be held.
Control parameters:: Control parameters must be in the primary address space.

Programming requirements

The user must provide a recovery environment if one is necessary during the invocation of the IVTCSM Service, as the service does not provide a recovery environment during all its functions.

The service provides for buffer reclamation at the following tasks:

End-of-memory
End-of-Job-Step-Task
Optionally, at abnormal end-of-task

See CSM recovery for normal and abnormal termination for more information.

Restrictions

The caller has the following restrictions:

Do not use MVS™ page-fix services directly for buffers provided by this service. Establish the BUFTYPE attribute of these buffers using CSM service requests.
Do not issue ALESERV delete for an ALET returned from CSM.

Input register information

Before issuing this macro, the caller must ensure that register 13 contains the address of a 72-byte standard save area in the primary address space.

Output register information

When control returns to the caller, the general purpose registers contain the following registers:

Register: Contents
0: Error reason code from the requested function
1: Used as work register by the system
2-13: Unchanged
14: Used as work register by the system
15: Return code from requested function