ALEBK | Back to Index page

| Prolog Control Block Contents ALEBK DSECT 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

     NAME       : HCPALEBK
     DESCRIPTION: Access List Entry
     DSECT      : ALEBK
     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.
     RELOCATION CONSIDERATIONS : None

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 7.2.0 Last updated on 24 Jun 2020 at 09:26:50 EDT.
Copyright IBM Corporation, 1990, 2020