ALEBK Back to Index page
Control Block Contents 
Storage Layout 
Cross Reference (Contains links to field and bit definitions)
Programming Interface Information:
This information is NOT intended to be
used as Programming Interfaces of z/VM.

  ALEBK Prolog Top of page
 DESCRIPTION: Access List Entry
 FUNCTION   : ALEBK maps the storage associated with one entry
              of an Access List.  The entries are used in
              access register translation.
 LOCATED BY : Access register translation.
              An Access List Entry is part of an Access List Entry
              Table. The beginning of the table is pointed to by
              an entry in the Dispatchable Unit Control Table
              (DUCT) or by the primary ASN Second Table Entry
              (ASTE).  The access list entry table is indexed into
              by an access list entry number (ALETEN).
 CREATED BY : ALEs designating entries in access lists created and
              managed by CP are formed by HCPALMAD.
 DELETED BY : ALEs designating entries in access lists created and
              managed by CP are deleted by HCPALMDL.
 SERIALIZED : This DSECT is to map guest storage, the user of
              the DSECT is responsible for serialization.
              It also maps ALEs in access lists created and managed
              by CP.  The ALCBK lock (ALCLOCK) is the serialization
              for changes to those entries.
  ALEBK Control Block Content Top of page

 ALEBK DSECT Top of page
Hex Dec Type/Val Lng Label (dup) Comments ---- ---- --------- ---- -------------- -------- 0000 0 Structure ALEBK Access List Entry 0000 0 Bitstring 16 ALE (0) 0000 0 Signed 4 ALEW0 (0) The first word of the ALEBK .... .... ALEW0INV X'80000000' ALEW0INV Invalid bit in ALE word 0 000ALEW0 ALEW0SNM X'00FF0000' ALEW0SNM ALE sequence number in word 0 000ALEW0 ALEW0SIG X'83FFFFFF' ALEW0SIG Defined bits in ALE word 0 0000 0 Bitstring 1 ALE0 First byte of entry 1... .... ALEINV X'80' ALEINV Access List Entry INValid bit - '1'B = the access-list entry is invalid. During AR translation involving this ALE, an ALEN-translation exception is recognized. .... ..1. ALEFONLY X'02' ALEFONLY Fetch only bit - indicates fetch only access to address space .... ...1 ALEPRIV X'01' ALEPRIV PRIVate Bit - '0'B = any program can use this entry. '1'B = programs must have an EAX (in CR8) which is identical to ALEAX, or the EAX (in CR8) must select an authority table secondary bit with a value of 1. 0001 1 Bitstring 1 ALESN ALE Sequence Number - is compared against the ALETSN in the ALET during access-register translation. Inequality causes an ALE-sequence exception to be recognized. 0002 2 Signed 2 ALEAX ALE Authorization IndeX - may be used to determine whether the program for which AR translation is being performed is authorized to use the access-list entry. See ALEPRIV for more info. 0004 4 Bitstring 4 * Reserved Bits 0 and 28-30 of the following field must be zeros. 0008 8 Address 4 ALEASTE (0) ASN Second Table Entry origin - the address of the ASTE for the specified address space. 00FFFFC0 ALEASTOM X'7FFFFFC0' Significant bits of ASTE origin. ANDed with ALEASTE to isolate address. 0008 8 Bitstring 1 * (3) Skip first three bytes of ASTEO 000B 11 Bitstring 1 ALEFLAGS Flag byte origin. ..1. .... ALERPRG1 X'20' Reserved for programming (in use) ALERPGR1 has two programming use definitions, one for use in the CP-use access list (ALENTDSP) and one for use in guest access lists (ALEPFAUL). Since an individual Access List Entry cannot be in both types of list at once, these two redefinitions of ALERPRG1 do not overlap. ..1. .... ALENTDSP X'20' When set in the CP-use access list, indicates the ALE designates an address space not owned by the dispatched user. ..1. .... ALEPFAUL X'20' When set in a guest access list, indicates page faults are eligible for asynchronous processing. (Pseudo page-fault bit) ...1 .... ALERPRG2 X'10' Reserved for programming (in use) ...1 .... ALERACC X'10' When set in a host access list, indicates the ALE designates that the address space be accessed with r-access. Otherwise, i-access should be used. 000C 12 Bitstring 4 ALEASTSN ASTE Sequence Number - compared against an ASTE sequence number (ASTSN) in the designated ASTE during access-register translation. 00000010 ALELEN *-ALEBK Entry size in bytes 00000002 ALESIZE (ALELEN+7)/8 Size in doublewords of the ALE *cmnt** ORG ALEBK+ALELEN Redefinition for second ALE in an access list: 0010 16 Bitstring 8 * Reserved Area reserved for programming... 0018 24 Address 4 ALEALCBK In access lists built by CP, the second access-list entry in each access list (the one with ALEN=1) contains a pointer to the ALCBK, CP's access-list control block. 001C 28 Signed 4 * Reserved for programming 00000004 ALENSHFT 4 Shift needed to transform ALEN into byte offset into access list.
  ALEBK Storage Layout Top of page
*** ALEBK - Access List Entry
*     +------+------+-------------+---------------------------+
*   0 |ALE0  |ALESN |   ALEAX     |///////////////////////////|
*     +------+------+------+------+---------------------------+
*   8 |////////////////////|:FLAGS|         ALEASTSN          |
*     +--------------------+------+---------------------------+
*  10 |///////////////////////////////////////////////////////|
*     +---------------------------+---------------------------+
*  18 |         ALEALCBK          |///////////////////////////|
*     +---------------------------+---------------------------+
*  20
*** ALEBK - Access List Entry
  ALEBK Cross Reference Top of page
Symbol         Dspl Value
-------------- ---- -----
ALE            0000
ALEALCBK       0018
ALEASTE        0008
ALEASTOM       0008 00FFFFC0
ALEASTSN       000C
ALEAX          0002
ALEFLAGS       000B
ALEFONLY       0000 02
ALEINV         0000 80
ALELEN         000C 00000010
ALENSHFT       001C 00000004
ALENTDSP       000B 20
ALEPFAUL       000B 20
ALEPRIV        0000 01
ALERACC        000B 10
ALERPRG1       000B 20
ALERPRG2       000B 10
ALESIZE        000C 00000002
ALESN          0001
ALEW0          0000
ALEW0INV       0000 00
ALEW0SIG       0000 000ALEW0
ALEW0SNM       0000 000ALEW0
ALE0           0000
This information is based on z/VM 6.3.0 Last updated on 22 May 2013 at 13:53:45 EDT.
Copyright IBM Corporation, 1990, 2013