REQUEST=CHANGEACCESS option of IARV64

The requirements for the caller are:

None.

This macro supports multiple versions. Some keywords are unique to certain versions. See PLISTVER parameter description.

Before issuing the IARV64 macro, the caller does not have to place any information into any register unless using it in register notation for a particular parameter, or using it as a base register.

Some callers depend on register contents remaining the same before and after issuing a service. If the system changes the contents of registers on which the caller depends, the caller must save them before issuing the service, and restore them after the system returns control.

None

The REQUEST=CHANGEACCESS option of the IARV64 macro is written as follows:

The parameters are explained as follows:

IARV64 REQUEST=CHANGEACCESS requests that the view type for segments within the specified 64-bit shared memory objects can be changed.

name

An optional symbol, starting in column 1, that is the name on the IARV64 macro invocation. The name must conform to the rules for an ordinary assembler language symbol.

REQUEST=CHANGEACCESS

REQUEST=CHANGEACCESS requests that the type of access to the specified virtual storage be changed. For 64-bit shared memory objects the scope of the change is determined by the choice of LOCAL versus GLOBAL on the IARV64 GETSHARED CHANGEACCESS keyword.

For 64-bit shared memory objects when CHANGEACCESS=LOCAL was specified or defaulted on the REQUEST=GETSHARED, only the address space specified by the ALET is affected.

For 64-bit shared memory objects when the CHANGEACCESS=GLOBAL is specified, all address spaces currently sharing the memory object are affected. Subsequent IARV64 SHAREMEMOBJ requests for this memory object will also be affected by this CHANGEACCESS when CHANGEACCESS=GLOBAL is specified (until the next CHANGEACCESS invocation).

The memory object specified must be a 64-bit shared memory object. For example, it is the result of a GETSHARED invocation

CHANGEACCESS requests for memory objects that are CHANGEACCESS=LOCAL require that the target space have interest in the shared memory object. For example, a SHAREMEMOBJ for the target space must have been done before the CHANGEACCESS request. Memory objects with CHANGEACCESS=GLOBAL support CHANGEACCESS requests without prior SHAREMEMOBJ requests.

,VIEW=READONLY

,VIEW=SHAREDWRITE

,VIEW=HIDDEN

A required input parameter that indicates the accessing mode on the area.

,VIEW=READONLY

This parameter specifies that the area can only be used to read data. Any attempt to alter data by writing onto the area will result in a program check.

,VIEW=SHAREDWRITE

This parameter specifies that the area can be used to read or update data.

,VIEW=HIDDEN

This parameter specifies that the data within the area cannot be accessed until its view type is changed to READONLY or SHAREDWRITE. Any attempt to access a hidden area will result in a program check.

,RANGLIST=ranglist

A required input parameter that contains the address of the ranglist. The range list consists of a number of entries (as specified by NUMRANGE) where each entry is 16 bytes long. A description of the fields in each range list entry follows:

VSA

VSA denotes the starting virtual address of the data to be acted on. The virtual address specified must be within a memory object returned by GETSHARED (not GETSTOR or GETCOMMON). The value must always be on a segment boundary.

NUMSEGMENTS

NUMSEGMENTS contains the number of segments (megabytes) in the area. The number of segments specified starting with the specified VSA must lie within a single memory object. The length of this field is 8 bytes.

To code: Specify the RS-type address, or address in register (2)-(12), of an eight-byte pointer field.

,NUMRANGE=numrange

,NUMRANGE=1

An optional input parameter that specifies the number of entries in the supplied range list.

The value specified must be no greater than 16. The default is 1.

To code: Specify the RS-type address, or address in register (2)-(12), of a fullword field.

,ALETVALUE=aletvalue

,ALETVALUE=0

An optional input parameter that indicates the ALET of the address space sharing a memory object that will change access to the memory object.

The only supported values are 0 (primary) and 2 (home).

To code: Specify the RS-type address, or address in register (2)-(12), of a fullword field.

,RETCODE=retcode

An optional output parameter into which the return code is to be copied from GPR 15.

To code: Specify the RS-type address of a fullword field, or register (2)-(12).

,RSNCODE=rsncode

An optional output parameter into which the reason code is to be copied from GPR 0.

To code: Specify the RS-type address of a fullword field, or register (2)-(12).

,PLISTVER=IMPLIED_VERSION

,PLISTVER=MAX

,PLISTVER=0, 1, 2, 3 or 4

An optional input parameter that specifies the version of the macro. PLISTVER determines which parameter list the system generates. PLISTVER is an optional input parameter on all forms of the macro, including the list form. When using PLISTVER, specify it on all macro forms used for a request and with the same value on all of the macro forms. The values are:

• IMPLIED_VERSION, which is the lowest version that allows all parameters specified on the request to be processed. If you omit the PLISTVER parameter, IMPLIED_VERSION is the default.
• MAX, if you want the parameter list to be the largest size currently possible. This size might grow from release to release and affect the amount of storage that your program needs.

  If you can tolerate the size change, IBM® recommends that you always specify PLISTVER=MAX on the list form of the macro. Specifying MAX ensures that the list-form parameter list is always long enough to hold all the parameters you might specify on the execute form, when both are assembled with the same level of the system. In this way, MAX ensures that the parameter list does not overwrite nearby storage.

• 0, supports all parameters except those specifically referenced in higher versions.
• 1, supports both the following parameters and parameters from version 0:
  • CONVERTSIZE64
  • CONVERTSTART
  • GUARDSIZE64
  • V64SHARED
• 2, supports both the following parameters and parameters from version 0 and 1:
  • AMOUNTSIZE
  • DETACHFIXED
  • DOAUTHCHECKS
  • DUMP
  • DUMPPRIORITY
  • DUMPPROTOCOL
  • LOCALSYSAREA
  • MEMLIMIT
  • OPTIONVALUE
  • ORDER
  • OWNERASID
  • OWNERCOM
  • TYPE
  • UNLOCKED
  • USERTOKEN
  • V64COMMON
• 3, supports both the following parameters and parameters from versions 0, 1, 2:
  • ATTRIBUTE
  • OWNERJOBNAME
  • TRACKINFO
• 4, supports both the following parameter and parameters from versions 0, 1, 2, 3:
  • DMAPAGETABLE

To code: Specify one of the following:

• IMPLIED_VERSION
• MAX
• A decimal value of 0, 1, 2, 3 or 4

,MF=S

,MF=(L,list addr)

,MF=(L,list addr,attr)

,MF=(L,list addr,0D)

,MF=(E,list addr)

,MF=(E,list addr,COMPLETE)

An optional input parameter that specifies the macro form.

Use MF=S to specify the standard form of the macro, which builds an inline parameter list and generates the macro invocation to transfer control to the service. MF=S is the default.

Use MF=L to specify the list form of the macro. Use the list form together with the execute form of the macro for applications that require reentrant code. The list form defines an area of storage that the execute form uses to store the parameters. Only the PLISTVER parameter may be coded with the list form of the macro.

Use MF=E to specify the execute form of the macro. Use the execute form together with the list form of the macro for applications that require reentrant code. The execute form of the macro stores the parameters into the storage area defined by the list form, and generates the macro invocation to transfer control to the service.

,list addr

The name of a storage area to contain the parameters. For MF=S and MF=E, this can be an RS-type address or an address in register (1)-(12).

,attr

An optional 1- to 60-character input string that you use to force boundary alignment of the parameter list. Use a value of 0F to force the parameter list to a word boundary, or 0D to force the parameter list to a doubleword boundary. If you do not code attr, the system provides a value of 0D.

,COMPLETE

Specifies that the system is to check for required parameters and supply defaults for omitted optional parameters.