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| Prolog Control Block Contents SXLBK DSECT SXLEN DSECT SXLEX DSECT SXLXL DSECT SXLSW 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.

SXLBK Control Block Content | Top of page

     SXLBK DSECT
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    Hex   Dec Type/Val   Lng Label (dup)    Comments
    ---- ---- --------- ---- -------------- --------
    0000    0 Structure      SXLBK          Distributed shared-exclusive spinlock.
    0000    0 Signed       4 SXLLOCKS       Mask of shares held of
                                            distributed shared- exclusive
                                            spinlocks. Values are defined in
                                            HCPEQUAT.
    0004    4 Signed       2 SXLCPUAD       CPU addr assigned to SXLBK.
    0006    6 Bitstring    1 SXLCPUTY       CPU type of the processor.
    0007    7 Bitstring    1 SXLFLAGS       Flags.
              1... ....      SXLCPUOF       X'80' SXLCPUOF Assigned CPU is
                                            offline.
              .1.. ....      SXLWASON       X'40' SXLWASON Processor was
                                            online at some point since IPL.
    0008    8 Signed       8 SXLTIME        TOD value at the time of the
                                            transition to the current state
                                            which is either online or
                                            offline.
    0010   16 Bitstring   64 SXLMALFM       Mask of all CPUs that have
                                            malfunctioned (this is the OR of
                                            SYSMALFM and PFXMALFM)
              00000050       SXLBUSED       (*-SXLBK) Size of used SXLBK
                                            space.
    0050   80 Bitstring  176 SXLBRSVD       Reserved for IBM use.
              00000020       SXLBKSZD       (*-SXLBK+7)/8 Size in double
                                            words.
              00000100       SXLBKSZB       SXLBKSZD*8 Size in bytes.

     SXLEN DSECT
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    Hex   Dec Type/Val   Lng Label (dup)    Comments
    ---- ---- --------- ---- -------------- --------
    0000    0 Structure      SXLEN          Distributed shared-exclusive spinlock.
          An SXLEN maps the processor local data area for a
          specific distributed shared-exclusive spinlock. It
          maintains a processors view of its lock hold state,
          contains the processor's lock usage statistics, and
          control data for using the lock.
          The SXLEN resides in an array of SXLENs with origin
          in PFXSXLEN. The SXLENs are indexed by the constant
          lock number value assigned to the lock corresponding
          to the bit position of the lock in the SXLLOCKS mask.
          Constants are defined in HCPEQUAT for the index values.
              00000001       SXLENMAX       SXLTOPLKI Maximum SXLEN entry
                                            number.
              00000000       SXLENSCO       SXLSCHLKI*SXLENSZB Offset of the
                                            Scheduler Lock SXLEN in an SXLEN
                                            array.
              00000200       SXLENTPO       SXLTOPLKI*SXLENSZB Offset of the
                                            Topology Lock SXLEN in an SXLEN
                                            array.
    0000    0 Signed       4 SXLEMASK       This lock's SXLLOCKS mask value.
    0004    4 Address      4 SXLEXLAD       Address of global data area for
                                            managing exclusive hold.
    0008    8 Address      4 SXLEBKAD       Address of this processor's SXLBK
                                            for managing this processor's
                                            share of the lock.
    000C   12 Signed       2 SXLENOFF       Offset into this processor's
                                            SXLEN array corresponding to its
                                            index position, SXLENNDX.
    000E   14 Bitstring    1 SXLENNDX       This lock's SXLEN index value
                                            which is the bit position in
                                            SXLENMSK.
    000F   15 Bitstring    1 SXLECTRL       Control settings.
              1... ....      SXLASSST       X'80' SXLASSST Assist used when
                                            1.
              .1.. ....      SXLNIAI2       X'40' SXLNIAI2 NIAI-2 used when
                                            1.
              ..1. ....      SXLNIAI4       X'20' SXLNIAI4 NIAI-4 used when
                                            1.
              ...1 ....      SXLNIAI8       X'10' SXLNIAI8 NIAI-7/8 used when
                                            1.
              .... 1...      SXLCAD         X'08' SXLCAD CAD used when 1.
                                            Only set if SXLPFD6 is also set.
              .... .1..      SXLPFD6        X'04' SXLPFD6 PFD-6/7 used when
                                            1.
              .... ..1.      SXLPPA14       X'02' SXLPPA14 PPA-14 used when
                                            1.
              .... ...1      SXLPPA15       X'01' SXLPPA15 PPA-15 used when
                                            1.
    0010   16 Bitstring   40 SXLESTAT (0)   Local lock state info.
    0010   16 Bitstring    1 SXLEFLB1       Lock specific flag byte 1.
              1... ....      SXLEXCL        X'80' SXLEXCL Attempting to
                                            acquire or currently holding
                                            exclusive.
              .1.. ....      SXLSHRD        X'40' SXLSHRD Attempting to
                                            acquire or currently holding a
                                            share.
              ..1. ....      SXLSH2EX       X'20' SXLSH2EX Attempting
                                            transition from shared to
                                            exclusive.
              ...1 ....      SXLEX2SH       X'10' SXLEX2SH Attempting
                                            transition from exclusive to
                                            shared.
              .... 1...      SXLSHPND       X'08' SXLSHPND This processor set
                                            SXLXLSPD.
              .... ....      SXLEFAVL       X'00' SXLEFAVL Available. Not
                                            held or pending.
    0011   17 Bitstring    1 SXLEFLB2       Flags for HCPSXL usage.
              1... ....      SXLESPIN       X'80' SXLESPIN DSPOLICY=SPIN
                                            specified.
              .1.. ....      SXLESQR0       X'40' SXLESQR0 DSPOLICY=RETURN
                                            with SQR=0 specified.
              ..1. ....      SXLESQRN       X'20' SXLESQRN DSPOLICY=RETURN
                                            with SQR<>0 specifi
              ...1 ....      SXLESPDX       X'10' SXLESPDX Exclusive was last
                                            blocked by share-pending, not
                                            excl.
              .... 1...      SXLETRAC       X'08' SXLETRAC TRACE requested
                                            flag. Used by HCPSXLAX and
                                            HCPSXLAS.
              .... .1..      SXLEEPND       X'04' SXLEEPND Exclusive pending.
                                            SXLXLHLD is set in SXLXL but
                                            share scan is needed.
              .... ..1.      SXLELKSQ       X'02' SXLELKSQ LOCKSEQ>0
                                            processing.
              .... ...1      SXLESKLK       X'01' SXLESKLK Skipped
                                            speculative setting of SXLLOCKS
                                            for share acquisition.
    0012   18 Signed       2 SXLESTSQ       Sequence number at start of
                                            attempt to acquire the lock.
    0014   20 Bitstring    1 SXLEFLAGS      Lock flags.
              1... ....      SXLLKSEQ       X'80' SXLLKSEQ LOCKSEQ is
                                            exploited.
    0015   21 Bitstring    1 *              Reserved for IBM use.
    0016   22 Signed       2 SXLETARG       Target CPU address blocking
                                            serialization acquisition. Used
                                            by HCPSXLFT.
    0018   24 Dbl-Word     8 *              Reserved for IBM use.
    0020   32 Dbl-Word     8 SXLEREQR (0)   Must be dword aligned.
    0020   32 Address      4 SXLEHLDA       Lock holder's address.
    0024   36 Address      4 SXLEVMDA       Lock holding VMDBK address.
    0028   40 Dbl-Word     8 SXLERELR (0)   Must be dword aligned.
    0028   40 Address      4 SXLERELA       Lock releaser's address.
    002C   44 Address      4 SXLEVMRA       Lock releaser VMDBK address.
    0030   48 Signed       8 SXLETOD        TOD savearea for calculating
                                            interval durations. End of
                                            SXLESTAT.
    0038   56 Dbl-Word     8 *              Reserved for IBM use.
          REQUEST COUNTS:
            Request counts are reported in mutually exclusive
            counts for each request type so that the sum of the
            individual counts indicates the overall request rate
            for that request type and method.
            For an rm value, the sum of the CU, CN and CSA values
            provided for that request type and method provides the
            total request count.  The CSX, CSP and CSS values
            provide details for the reasons for the spin, but the
            sum of those is likely to be greater than the CSA value
            because an exclusive request might wait because of an
            exclusive hold, or share-pending, but then also wait
            because of shares.
            The total share requests is the sum of the total for the
            rm values SC, SL and SU. For exclusive, sum XC and XU.
            Various subtotals are meaningful and referred to below:
              Ctot - total requests.
              Ltot - total lock acquisitions (CN + CSA).
              Stot - total lock spins. Normally CSA, but for
                     rm = SL, Stot = CU + CSA because the CU
                     value represents the number of spins started,
                     but cancelled before the lock was acquired.
            Comparing the relative percentages of the Ctot values
            across rm values provides indications of which request
            types and modifiers are most common.
            Counts of unsuccessful conditional lock requests.
            These values are used to determine the failure rates of
            conditional lock requests.
            - for rm = SC, XC, and SX:
              %failure = 100*CU/Ctot
            - for rm = SL (internal spin loop might have been
              cancelled)
              %failure = 100*CU/Ctot
    0040   64 Dbl-Word     8 SXLESCCU       Count of unsuccessful share
                                            requests with DSPOLICY=RETURN but
                                            LOCKSEQ was not specified.
    0048   72 Dbl-Word     8 SXLESLCU       Count of unsuccessful share
                                            requests with DSPOLICY=RETURN and
                                            LOCKSEQ but the invoker cancelled
                                            the spin before the share was
                                            acquired.
    0050   80 Dbl-Word     8 SXLEXCCU       Count of unsuccessful exclusive
                                            requests with DSPOLICY=RETURN.
    0058   88 Dbl-Word     8 SXLESXCU       Count of unsuccessful SHR2EX
                                            requests (promote).
            Counts of successful lock acquisitions not requiring a
            spin.
            Ltot(rm = SC, XC, XS and SX) = CN
               because those request types don't spin.
            These values are used with the spin counts to determine
            Ltot and collision rates for rm = SL, SU and XU which
            are request types that can spin. See the next section.
    0060   96 Dbl-Word     8 SXLESCCN       Count of shares acquired by
                                            requests with DSPOLICY=RETURN but
                                            LOCKSEQ was not specified.
    0068  104 Dbl-Word     8 SXLESLCN       Count of shares acquired by
                                            requests with DSPOLICY=RETURN and
                                            LOCKSEQ that did not require a
                                            spin in the invoker.
    0070  112 Dbl-Word     8 SXLESUCN       Count of shares acquired by
                                            requests with DSPOLICY=SPIN that
                                            did not require a spin.
    0078  120 Dbl-Word     8 SXLEXCCN       Count of exclusive acquisitions
                                            by requests with DSPOLICY=RETURN.
    0080  128 Dbl-Word     8 SXLEXUCN       Count of exclusive acquisitions
                                            by requests with DSPOLICY=SPIN
                                            that did not require a spin.
    0088  136 Dbl-Word     8 SXLESXCN       Count of SHR2EX requests that
                                            successfully promoted from a
                                            share to exclusive.
    0090  144 Dbl-Word     8 SXLEXSCN       Count of EX2SHR requests that
                                            successfully demoted from an
                                            exclusive to share.
            Counts of lock requests that spun trying to acquire the
            lock for any reason. Incremented once per lock
            acquisition that spins for one or multiple reasons.
            Ltot(rm = SL, SU, and XU) = CN + CSA
               because those request types spin.
            Lock collision rates as a percentage of total
            acquisitions
               100*CSA/Ltot
            Lock collision rates as a percentage of total requests
               100*Stot/Ctot
    0098  152 Dbl-Word     8 SXLESLCSA      Count of shares acquired by
                                            requests with DSPOLICY=RETURN and
                                            LOCKSEQ that required a spin in
                                            the invoker for any reason.
    00A0  160 Dbl-Word     8 SXLESUCSA      Count of shares acquired by
                                            requests with DSPOLICY=SPIN that
                                            required a spin for any reason.
    00A8  168 Dbl-Word     8 SXLEXUCSA      Count of exclusive acquisitions
                                            by requests with DSPOLICY=SPIN
                                            that required a spin for any
                                            reason.
            Counts of lock requests that spun for a specific reason
            during lock acquisition. Incremented once per request
            that spins for that specific reason.
            Collision rates for specific reasons can be calculated
            using these values in place of the CSA values.
    00B0  176 Dbl-Word     8 SXLESLCSX      Count of shares acquired by
                                            requests with DSPOLICY=RETURN and
                                            LOCKSEQ that required a spin in
                                            the invoker to wait for exclusive
                                            to be released.
    00B8  184 Dbl-Word     8 SXLESUCSX      Count of shares acquired by
                                            requests with DSPOLICY=SPIN that
                                            required a spin to wait for
                                            exclusive to be released.
    00C0  192 Dbl-Word     8 SXLEXUCSX      Count of exclusive acquisitions
                                            by requests with DSPOLICY=SPIN
                                            that required a spin to wait for
                                            exclusive to be released.
    00C8  200 Dbl-Word     8 SXLEXUCSP      Count of exclusive acquisitions
                                            by requests with DSPOLICY=SPIN
                                            that required a spin to wait
                                            because share-pending was set.
    00D0  208 Dbl-Word     8 SXLEXUCSS      Count of exclusive acquisitions
                                            by requests with DSPOLICY=SPIN
                                            that required a spin to wait for
                                            one or more shares to be
                                            released.
            Spin times when the lock was not immediately available.
            These values accumulate time only when the request is
            spinning for the specified condition.
            STIMtot = Total spin time for all share requests is the
            sum of the TSX and TSU values for SL and SU rm values
            because it should include spin time for cancelled spins.
            STIMtot(rm = SL) = TSX + TSU
            STIMtot(rm = SU) = TSX
            STIMtot = Total spin time for exclusive acquisitions is
            SUM of the TSX, TSP and TSS values for the XU rm value.
            STIMtot(rm = XU) = TSX + TSP + TSS
            Average spin time = STIMtot/Stot.
            Spin % busy can be calculated from the STIMtot values.
            Average spin time and spin % busy can also be calculated
            for the individual spin conditions for exclusive.
    00D8  216 Signed       8 SXLESLTSU      Time spent spinning on share
                                            requests with DSPOLICY=RETURN and
                                            LOCKSEQ after beginning a spin in
                                            the invoker but ending the spin
                                            before the share was acquired.
    00E0  224 Signed       8 SXLESLTSX      Time spent spinning on share
                                            requests with DSPOLICY=RETURN and
                                            LOCKSEQ that required a spin in
                                            the invoker to wait for exclusive
                                            to be released.
    00E8  232 Signed       8 SXLESUTSX      Time spent spinning on share
                                            requests with DSPOLICY=SPIN that
                                            required a spin to wait for
                                            exclusive to be released.
    00F0  240 Signed       8 SXLEXUTSX      Portion of time acquiring
                                            exclusive with DSPOLICY=SPIN
                                            spent spinning waiting for an
                                            exclusive hold to be released.
    00F8  248 Signed       8 SXLEXUTSP      Portion of time acquiring
                                            exclusive with DSPOLICY=SPIN
                                            spent spinning waiting for
                                            share-pending to be removed.
    0100  256 Signed       8 SXLEXUTSS      Portion of time acquiring
                                            exclusive with DSPOLICY=SPIN
                                            spent spinning waiting for shares
                                            to be released.
            Share-pending usage statistics.
            In general, the higher the ratio of PO/PS, the better
            because it represents efficient usage. A ratio value
            near or below the number of processors is reasonable.
            When calculating the ratio, use the sum of the PO and
            sum of the PS values.
    0108  264 Dbl-Word     8 SXLESUPS       Count of times share-pending was
                                            set to acquire a share excluding
                                            LOCKSEQ spins.
    0110  272 Dbl-Word     8 SXLESLPS       Count of times share-pending was
                                            set to acquire a share during a
                                            LOCKSEQ spin.
    0118  280 Dbl-Word     8 SXLESLPR       Count of times share-pending was
                                            removed in a LOCKSEQ spin after
                                            previously setting it without
                                            acquiring a share.
    0120  288 Dbl-Word     8 SXLESCPO       Count of times share-pending was
                                            set when acquiring a conditional
                                            share acquisition excluding
                                            LOCKSEQ spin.
    0128  296 Dbl-Word     8 SXLESLPO       Count of times share-pending was
                                            observed when getting a share
                                            during a LOCKSEQ spin.
    0130  304 Dbl-Word     8 SXLESUPO       Count of times share-pending was
                                            observed during an unconditional
                                            share acquisition.
            Shares observed during exclusive acquisition.
            The ratio SO/CSS is the average number of shares for
            which an exclusive request had to wait while spinning on
            shares.  The value will be greater than 1, but is not
            expected to be a lot higher because while the exclusive
            request is waiting for the first share, other processors
            are in the process of finishing up their holds as well.
    0138  312 Dbl-Word     8 SXLEXUSO       Number of CPUs observed holding
                                            shares while attempting to
                                            acquire the lock exclusive.
            Exclusive requests observed during lock acquisition.
            The ratio XO/CSX for an rm value is the average number
            of exclusive acquisitions by other processors that occur
            while the rm type requests are blocked by exclusive
            hold. The higher the ratios, the more likely the ratio
            CSX/Ltot is high. A high CSX/Ltot ratio would be closer
            to 1, while a high XO/CSX ratio would be higher than 2.
            These ratios can be calculated for rm = SL, SU and XU.
    0140  320 Dbl-Word     8 SXLESLXO       The number of exclusive lock
                                            acquisitions that occurred while
                                            other requests spun getting a
                                            share in HCPDSP using its local
                                            spin.
    0148  328 Dbl-Word     8 SXLESUXO       The number of exclusive lock
                                            acquisitions that occurred while
                                            other requests spun getting a
                                            share excluding HCPDSP local
                                            spin.
    0150  336 Dbl-Word     8 SXLEXUXO       The number of exclusive lock
                                            acquisitions that occurred while
                                            other requests spun getting
                                            exclusive.
    0158  344 Signed       4 SXLECADS       Count of CAD instructions for
                                            shared lock requests.
    015C  348 Signed       4 SXLECADX       Count of CAD instructions for
                                            exclusive lock requests.
    0160  352 Bitstring   24 SXLEXSLX       LOCKSEQ share requests blocked by
                                            exclusive.
    0178  376 Bitstring   24 SXLEXSUX       Unconditional share requests
                                            blocked by exclusive.
    0190  400 Bitstring   24 SXLEXXUX       Exclusive requests blocked by
                                            exclusive.
    01A8  424 Bitstring   24 SXLEXXUP       Exclusive requests blocked by
                                            share-pending.
    01C0  448 Bitstring   24 SXLEXXUS       Exclusive requests blocked by
                                            CPUs holding shares.
              000001D8       SXLEUSED       (*-SXLEN) Size of used SXLEN
                                            space.
    01D8  472 Bitstring   40 SXLERSVD       Reserved for IBM use.
              00000040       SXLENSZD       (*-SXLEN+7)/8 Size in double
                                            words.
              00000200       SXLENSZB       SXLENSZD*8 Size in bytes.
          SXLEX maps each of the four SXLEXxxx elements in the SXLEN.

     SXLEX DSECT
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    Hex   Dec Type/Val   Lng Label (dup)    Comments
    ---- ---- --------- ---- -------------- --------
    0000    0 Structure      SXLEX          Distributed shared-exclusive spinlock.
    0000    0 Signed       4 SXLEX9T        Count of attempts to identify a
                                            diagnose x'9C' target.
    0004    4 Signed       4 SXLEX9S        Count of potential targets
                                            considered (for which a SIGP SRS
                                            was performed).
    0008    8 Signed       4 SXLEX9F        Count of times target was found.
    000C   12 Signed       4 SXLEX9C        Count of Diag x'9C's issued.
    0010   16 Signed       4 SXLEX44        Count of Diag x'44's issued.
    0014   20 Signed       4 *              Reserved for IBM use.
              00000018       SXLEXSZB       *-SXLEX Size in bytes.
          SXLXL maps the eXclusive Lock data in the global area.

     SXLXL DSECT
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    Hex   Dec Type/Val   Lng Label (dup)    Comments
    ---- ---- --------- ---- -------------- --------
    0000    0 Structure      SXLXL          Distributed shared-exclusive spinlock.
    0000    0 Dbl-Word     8 SXLXLOCK (0)   Exclusive lock state.
    0000    0 Signed       4 SXLXLWD1 (0)   Word 1 of lock state.
              SXLXLWD1       SXLAVLW1       X'0000FFFF' SXLAVLW1 Available
                                            for exclusive value for word 1 of
                                            lock.
    0000    0 Bitstring    1 SXLXLFLG       Exclusive lock flags.
              1... ....      SXLXLHLD       X'80' SXLXLHLD Exclusive held.
              .1.. ....      SXLXLSPD       X'40' SXLXLSPD Share pending.
              11.. ....      SXLXLNAV       X'C0' SXLXLNAV Flags making lock
                                            not available.
              .... ....      SXLXLAVL       X'00' SXLXLAVL Available. Not
                                            held or pending.
    0001    1 Bitstring    1 *              Reserved for IBM use.
    0002    2 Signed       2 SXLXLCPU       CPU address of processor with
                                            hold or pending hold. Set to
                                            X'FFFF' when not held.
              0000FFFF       SXLNOCPU       X'FFFF' Indicates no CPU hold the
                                            lock.
    0004    4 Signed       4 SXLXLWD2 (0)   Word 2 of lock state.
    0004    4 Signed       2 SXLXLSEQ       Exclusive obtain sequence num.
                                            Incremented at time of release.
              00010000       SXLSQINC       X'00010000' Constant used to
                                            increment the sequence number by
                                            1.
    0006    6 Signed       2 SXLXLCPS       CPU address of processor with
                                            pending share. Set to X'FFFF'
                                            when not pending.
    0008    8 Address      4 SXLXLENO       SXLEN offset in a processor'
                                            SXLEN array. Add to PFXSXLEN to
                                            calculate the address.
    000C   12 Signed       4 SXLXLMSK       This lock's SXLLOCKS mask value.
    0010   16 Address      4 SXLXBKST       Address of SXLBK array origin.
    0014   20 Signed       2 SXLXLSQT       Sequence number increase
                                            threshold for setting pending
                                            share (SXLXLSPD).
    0016   22 Signed       2 SXLXLSQTL      Sequence number increase
                                            threshold for setting pending
                                            share (SXLXLSPD). for use with
                                            LOCKSEQ.
              00000003       SXLTHRESH      3 Default SXLXSQT and SXLXSQTL
                                            value.
    0018   24 Dbl-Word     8 *              Reserved for IBM use.
              00000004       SXLXLSZD       (*-SXLXL+7)/8 Size in double
                                            words.
              00000020       SXLXLSZB       SXLXLSZD*8 Size in bytes.
           SXLSW is a redefinition of the PFXTMPSG SVGWRK area for
           use by HCPSXL and that macros that call its entry points.
           All invokers of the macros must have PFXTMPSG available
           for use by the macros and potential calls to HCPSXL.
           The macros and HCPSXL share the usage of this area with
           some areas for use by the macros and expected to have
           been set before calls to HCPSXL.
           This area is used by setting up usage as:
             HCPUSING SXLSW,PFXTMPSG+(SVGWRK-SVGBK),PFXPG

     SXLSW DSECT
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    Hex   Dec Type/Val   Lng Label (dup)    Comments
    ---- ---- --------- ---- -------------- --------
    0000    0 Structure      SXLSW          Distributed shared-exclusive spinlock.
    0000    0 Dbl-Word     8 * (0)          PFXTMPSG.SVGWRK0
    0000    0 Signed       4 SXLSR14H       Macro R14 highhalf savearea.
    0004    4 Signed       4 SXLSR15H       Macro R15 highhalf savearea.
    0008    8 Dbl-Word     8 * (0)          PFXTMPSG.SVGWRK1
    0008    8 Dbl-Word     8 SXLSR0SV       Macro GR0 savearea.
    0010   16 Dbl-Word     8 * (0)          PFXTMPSG.SVGWRK2
    0010   16 Signed       4 SXLFTPRT (0)   Footprint state.
    0010   16 Bitstring    1 SXLSCTRL       Cached copy of SXLECTRL.
    0011   17 Bitstring    1 SXLFTPTX       Footprint of X error checks.
              1... ....      SXLFTXFM       X'80' SXLFTXFM Exclusive
                                            acquisition check of SXLEFLB1
                                            successful (macro).
              .1.. ....      SXLFTXPM       X'40' SXLFTXPM Exclusive
                                            acquisition check of SXLXLCPS
                                            successful (macro).
              ..1. ....      SXLFTXFA       X'20' SXLFTXFA Exclusive
                                            acquisition check of SXLEFLB1
                                            successful (HCPSXL).
              ...1 ....      SXLFTXXC       X'10' SXLFTXXC Exclusive
                                            acquisition check of SXLXLCPU
                                            successful (HCPSXL).
              .... 1...      SXLFTXPA       X'08' SXLFTXPA Exclusive
                                            acquisition check of SXLXLCPS
                                            successful (HCPSXL).
    0012   18 Bitstring    1 SXLFTPSM       Footprint of S error checks.
              1... ....      SXLFTSFM       X'80' SXLFTSFM Shared acquisition
                                            check 1 of SXLEFLB1 successful
                                            (macro).
              .1.. ....      SXLFTSFN       X'40' SXLFTSFN Shared acquisition
                                            check 2 of SXLEFLB1 successful
                                            (macro).
              ..1. ....      SXLFTSL1       X'20' SXLFTSL1 Shared acquisition
                                            check 1 of SXLLOCKS successful
                                            (macro).
              ...1 ....      SXLFTSL2       X'10' SXLFTSL2 Shared acquisition
                                            check 2 of SXLLOCKS successful
                                            (macro).
              .... 1...      SXLFTSL3       X'08' SXLFTSL3 Shared acquisition
                                            check 3 of SXLLOCKS successful
                                            (macro).
              .... .1..      SXLFTSL4       X'04' SXLFTSL4 Shared acquisition
                                            check 4 of SXLLOCKS successful
                                            (macro).
    0013   19 Bitstring    1 SXLFTPSA       Footprint of S error checks.
              1... ....      SXLFTSFA       X'80' SXLFTSFA Shared acquisition
                                            check of SXLEFLB1 successful
                                            (HCPSXL).
              .1.. ....      SXLFTSL5       X'40' SXLFTSL5 Shared acquisition
                                            check 5 of SXLLOCKS successful
                                            (HCPSXL).
              ..1. ....      SXLFTSXC       X'20' SXLFTSXC Shared acquisition
                                            check of SXLXLCPU successful
                                            (HCPSXL).
              ...1 ....      SXLFTSP1       X'10' SXLFTSP1 Shared acquisition
                                            check 1 of SXLXLCPS successful
                                            (HCPSXL).
              .... 1...      SXLFTSP2       X'08' SXLFTSP2 Shared acquisition
                                            check 2 of SXLXLCPS successful
                                            (HCPSXL).
              .... .1..      SXLFTSP3       X'04' SXLFTSP3 Shared acquisition
                                            check 3 of SXLXLCPS successful
                                            (HCPSXL).
    0014   20 Signed       4 *              Reserved for IBM use. These are
                                            ordered old and then new to allow
                                            STMG after the CSG as long as it
                                            uses consecutive registsers as R1
                                            and R3.
    0018   24 Dbl-Word     8 * (0)          PFXTMPSG.SVGWRK3
    0018   24 Dbl-Word     8 SXLLKOBS       Last observed SXLXLOCK value. For
                                            passing value to HCPSXLAX, old
                                            value after successful CSG, when
                                            acquiring a share, etc.
    0020   32 Dbl-Word     8 * (0)          PFXTMPSG.SVGWRK4
    0020   32 Dbl-Word     8 SXLLKNEW       SXLXLOCK CSG new value. Also
                                            value at time of last checked for
                                            share obtains.
    0028   40 Dbl-Word     8 * (0)          PFXTMPSG.SVGWRK5
    0028   40 Dbl-Word     8 SXLTRSV1       Trace EP register savearea 1.
    0030   48 Dbl-Word     8 * (0)          PFXTMPSG.SVGWRK6
    0030   48 Dbl-Word     8 SXLFNDRT       FINDUDSH return address
    0038   56 Dbl-Word     8 * (0)          PFXTMPSG.SVGWRK7
    0038   56 Bitstring    1 SXLPSWMSK      Save/restore byte for PSW bits
                                            0-7 at the Malfunction Alert
                                            Window
    0039   57 Bitstring    1 *              Reserved for IBM use.
    003A   58 Signed       2 SXLDWOFF       count for SXLLK macro loop
                                            control. This count increments by
                                            8 to align with each DW of a
                                            bitmask that is MAXVMPRC in
                                            length
    003C   60 Signed       4 SXLCR0         Save/restore area for CR0 at the
                                            Malfunction Alert Window

SXLBK Storage Layout | Top of page

    *** SXLBK - Distributed shared-exclusive spinlock.
    *
    *     +---------------------------+-------------+------+------+
    *   0 |         SXLLOCKS          |  SXLCPUAD   |:CPUTY|:FLAGS|
    *     +---------------------------+-------------+------+------+
    *   8 |                       SXLTIME                         |
    *     +-------------------------------------------------------+
    *  10 |                                                       |
    *     =                       SXLMALFM                        =
    *     |                                                       |
    *     +-------------------------------------------------------+
    *  50 |                                                       |
    *     =                       SXLBRSVD                        =
    *     |                                                       |
    *     +-------------------------------------------------------+
    * 100
    *
    *** SXLBK - Distributed shared-exclusive spinlock.

    *** SXLEN - Distributed shared-exclusive spinlock.
    *
    *     +---------------------------+---------------------------+
    *   0 |         SXLEMASK          |         SXLEXLAD          |
    *     +---------------------------+-------------+------+------+
    *   8 |         SXLEBKAD          |  SXLENOFF   |:ENNDX|:ECTRL|
    *     +------+------+-------------+------+------+------+------+
    *  10 |:EFLB1|:EFLB2|  SXLESTSQ   |(014) |//////|  SXLETARG   |
    *     +------+------+-------------+------+------+-------------+
    *  18 |///////////////////////////////////////////////////////|
    *     +---------------------------+---------------------------+
    *  20 |         SXLEHLDA          |         SXLEVMDA          |
    *     +---------------------------+---------------------------+
    *  28 |         SXLERELA          |         SXLEVMRA          |
    *     +---------------------------+---------------------------+
    *  30 |                       SXLETOD                         |
    *     +-------------------------------------------------------+
    *  38 |///////////////////////////////////////////////////////|
    *     +-------------------------------------------------------+
    *  40 |                       SXLESCCU                        |
    *     +-------------------------------------------------------+
    *  48 |                       SXLESLCU                        |
    *     +-------------------------------------------------------+
    *  50 |                       SXLEXCCU                        |
    *     +-------------------------------------------------------+
    *  58 |                       SXLESXCU                        |
    *     +-------------------------------------------------------+
    *  60 |                       SXLESCCN                        |
    *     +-------------------------------------------------------+
    *  68 |                       SXLESLCN                        |
    *     +-------------------------------------------------------+
    *  70 |                       SXLESUCN                        |
    *     +-------------------------------------------------------+
    *  78 |                       SXLEXCCN                        |
    *     +-------------------------------------------------------+
    *  80 |                       SXLEXUCN                        |
    *     +-------------------------------------------------------+
    *  88 |                       SXLESXCN                        |
    *     +-------------------------------------------------------+
    *  90 |                       SXLEXSCN                        |
    *     +-------------------------------------------------------+
    *  98 |                      SXLESLCSA                        |
    *     +-------------------------------------------------------+
    *  A0 |                      SXLESUCSA                        |
    *     +-------------------------------------------------------+
    *  A8 |                      SXLEXUCSA                        |
    *     +-------------------------------------------------------+
    *  B0 |                      SXLESLCSX                        |
    *     +-------------------------------------------------------+
    *  B8 |                      SXLESUCSX                        |
    *     +-------------------------------------------------------+
    *  C0 |                      SXLEXUCSX                        |
    *     +-------------------------------------------------------+
    *  C8 |                      SXLEXUCSP                        |
    *     +-------------------------------------------------------+
    *  D0 |                      SXLEXUCSS                        |
    *     +-------------------------------------------------------+
    *  D8 |                      SXLESLTSU                        |
    *     +-------------------------------------------------------+
    *  E0 |                      SXLESLTSX                        |
    *     +-------------------------------------------------------+
    *  E8 |                      SXLESUTSX                        |
    *     +-------------------------------------------------------+
    *  F0 |                      SXLEXUTSX                        |
    *     +-------------------------------------------------------+
    *  F8 |                      SXLEXUTSP                        |
    *     +-------------------------------------------------------+
    * 100 |                      SXLEXUTSS                        |
    *     +-------------------------------------------------------+
    * 108 |                       SXLESUPS                        |
    *     +-------------------------------------------------------+
    * 110 |                       SXLESLPS                        |
    *     +-------------------------------------------------------+
    * 118 |                       SXLESLPR                        |
    *     +-------------------------------------------------------+
    * 120 |                       SXLESCPO                        |
    *     +-------------------------------------------------------+
    * 128 |                       SXLESLPO                        |
    *     +-------------------------------------------------------+
    * 130 |                       SXLESUPO                        |
    *     +-------------------------------------------------------+
    * 138 |                       SXLEXUSO                        |
    *     +-------------------------------------------------------+
    * 140 |                       SXLESLXO                        |
    *     +-------------------------------------------------------+
    * 148 |                       SXLESUXO                        |
    *     +-------------------------------------------------------+
    * 150 |                       SXLEXUXO                        |
    *     +---------------------------+---------------------------+
    * 158 |         SXLECADS          |         SXLECADX          |
    *     +---------------------------+---------------------------+
    * 160 |                                                       |
    *     =                       SXLEXSLX                        =
    *     |                                                       |
    *     +-------------------------------------------------------+
    * 178 |                                                       |
    *     =                       SXLEXSUX                        =
    *     |                                                       |
    *     +-------------------------------------------------------+
    * 190 |                                                       |
    *     =                       SXLEXXUX                        =
    *     |                                                       |
    *     +-------------------------------------------------------+
    * 1A8 |                                                       |
    *     =                       SXLEXXUP                        =
    *     |                                                       |
    *     +-------------------------------------------------------+
    * 1C0 |                                                       |
    *     =                       SXLEXXUS                        =
    *     |                                                       |
    *     +-------------------------------------------------------+
    * 1D8 |                                                       |
    *     =                       SXLERSVD                        =
    *     |                                                       |
    *     +-------------------------------------------------------+
    * 200
    *
    *** SXLEN - Distributed shared-exclusive spinlock.

    *** SXLEX - Distributed shared-exclusive spinlock.
    *
    *     +---------------------------+---------------------------+
    *   0 |         SXLEX9T           |         SXLEX9S           |
    *     +---------------------------+---------------------------+
    *   8 |         SXLEX9F           |         SXLEX9C           |
    *     +---------------------------+---------------------------+
    *  10 |         SXLEX44           |///////////////////////////|
    *     +---------------------------+---------------------------+
    *  18
    *
    *** SXLEX - Distributed shared-exclusive spinlock.

    *** SXLXL - Distributed shared-exclusive spinlock.
    *
    *     +------+------+-------------+-------------+-------------+
    *   0 |:XLFLG|//////|  SXLXLCPU   |  SXLXLSEQ   |  SXLXLCPS   |
    *     +------+------+-------------+-------------+-------------+
    *   8 |         SXLXLENO          |         SXLXLMSK          |
    *     +---------------------------+-------------+-------------+
    *  10 |         SXLXBKST          |  SXLXLSQT   | SXLXLSQTL   |
    *     +---------------------------+-------------+-------------+
    *  18 |///////////////////////////////////////////////////////|
    *     +-------------------------------------------------------+
    *  20
    *
    *** SXLXL - Distributed shared-exclusive spinlock.

    *** SXLSW - Distributed shared-exclusive spinlock.
    *
    *     +---------------------------+---------------------------+
    *   0 |         SXLSR14H          |         SXLSR15H          |
    *     +---------------------------+---------------------------+
    *   8 |                       SXLSR0SV                        |
    *     +------+------+------+------+---------------------------+
    *  10 |:SCTRL|:FTPTX|:FTPSM|:FTPSA|///////////////////////////|
    *     +------+------+------+------+---------------------------+
    *  18 |                       SXLLKOBS                        |
    *     +-------------------------------------------------------+
    *  20 |                       SXLLKNEW                        |
    *     +-------------------------------------------------------+
    *  28 |                       SXLTRSV1                        |
    *     +-------------------------------------------------------+
    *  30 |                       SXLFNDRT                        |
    *     +------+------+-------------+---------------------------+
    *  38 |(038) |//////|  SXLDWOFF   |          SXLCR0           |
    *     +------+------+-------------+---------------------------+
    *  40
    *
    *** SXLSW - Distributed shared-exclusive spinlock.

SXLBK Cross Reference | Top of page

    Symbol         Dspl Value
    -------------- ---- -----
    SXLASSST       000F 80
    SXLAVLW1       0000 SXLXLWD1
    SXLBKSZB       0050 00000100
    SXLBKSZD       0050 00000020
    SXLBRSVD       0050
    SXLBUSED       0010 00000050
    SXLCAD         000F 08
    SXLCPUAD       0004
    SXLCPUOF       0007 80
    SXLCPUTY       0006
    SXLCR0         003C
    SXLDWOFF       003A
    SXLEBKAD       0008
    SXLECADS       0158
    SXLECADX       015C
    SXLECTRL       000F
    SXLEEPND       0011 04
    SXLEFAVL       0010 00
    SXLEFLAGS      0014
    SXLEFLB1       0010
    SXLEFLB2       0011
    SXLEHLDA       0020
    SXLELKSQ       0011 02
    SXLEMASK       0000
    SXLENMAX       0000 00000001
    SXLENNDX       000E
    SXLENOFF       000C
    SXLENSCO       0000 00000000
    SXLENSZB       01D8 00000200
    SXLENSZD       01D8 00000040
    SXLENTPO       0000 00000200
    SXLERELA       0028
    SXLERELR       0028
    SXLEREQR       0020
    SXLERSVD       01D8
    SXLESCCN       0060
    SXLESCCU       0040
    SXLESCPO       0120
    SXLESKLK       0011 01
    SXLESLCN       0068
    SXLESLCSA      0098
    SXLESLCSX      00B0
    SXLESLCU       0048
    SXLESLPO       0128
    SXLESLPR       0118
    SXLESLPS       0110
    SXLESLTSU      00D8
    SXLESLTSX      00E0
    SXLESLXO       0140
    SXLESPDX       0011 10
    SXLESPIN       0011 80
    SXLESQRN       0011 20
    SXLESQR0       0011 40
    SXLESTAT       0010
    SXLESTSQ       0012
    SXLESUCN       0070
    SXLESUCSA      00A0
    SXLESUCSX      00B8
    SXLESUPO       0130
    SXLESUPS       0108
    SXLESUTSX      00E8
    SXLESUXO       0148
    SXLESXCN       0088
    SXLESXCU       0058
    SXLETARG       0016
    SXLETOD        0030
    SXLETRAC       0011 08
    SXLEUSED       01C0 000001D8
    SXLEVMDA       0024
    SXLEVMRA       002C
    SXLEXCCN       0078
    SXLEXCCU       0050
    SXLEXCL        0010 80
    SXLEXLAD       0004
    SXLEXSCN       0090
    SXLEXSLX       0160
    SXLEXSUX       0178
    SXLEXSZB       0014 00000018
    SXLEXUCN       0080
    SXLEXUCSA      00A8
    SXLEXUCSP      00C8
    SXLEXUCSS      00D0
    SXLEXUCSX      00C0
    SXLEXUSO       0138
    SXLEXUTSP      00F8
    SXLEXUTSS      0100
    SXLEXUTSX      00F0
    SXLEXUXO       0150
    SXLEXXUP       01A8
    SXLEXXUS       01C0
    SXLEXXUX       0190
    SXLEX2SH       0010 10
    SXLEX44        0010
    SXLEX9C        000C
    SXLEX9F        0008
    SXLEX9S        0004
    SXLEX9T        0000
    SXLFLAGS       0007
    SXLFNDRT       0030
    SXLFTPRT       0010
    SXLFTPSA       0013
    SXLFTPSM       0012
    SXLFTPTX       0011
    SXLFTSFA       0013 80
    SXLFTSFM       0012 80
    SXLFTSFN       0012 40
    SXLFTSL1       0012 20
    SXLFTSL2       0012 10
    SXLFTSL3       0012 08
    SXLFTSL4       0012 04
    SXLFTSL5       0013 40
    SXLFTSP1       0013 10
    SXLFTSP2       0013 08
    SXLFTSP3       0013 04
    SXLFTSXC       0013 20
    SXLFTXFA       0011 20
    SXLFTXFM       0011 80
    SXLFTXPA       0011 08
    SXLFTXPM       0011 40
    SXLFTXXC       0011 10
    SXLLKNEW       0020
    SXLLKOBS       0018
    SXLLKSEQ       0014 80
    SXLLOCKS       0000
    SXLMALFM       0010
    SXLNIAI2       000F 40
    SXLNIAI4       000F 20
    SXLNIAI8       000F 10
    SXLNOCPU       0002 0000FFFF
    SXLPFD6        000F 04
    SXLPPA14       000F 02
    SXLPPA15       000F 01
    SXLPSWMSK      0038
    SXLSCTRL       0010
    SXLSHPND       0010 08
    SXLSHRD        0010 40
    SXLSH2EX       0010 20
    SXLSQINC       0004 00010000
    SXLSR0SV       0008
    SXLSR14H       0000
    SXLSR15H       0004
    SXLTHRESH      0016 00000003
    SXLTIME        0008
    SXLTRSV1       0028
    SXLWASON       0007 40
    SXLXBKST       0010
    SXLXLAVL       0000 00
    SXLXLCPS       0006
    SXLXLCPU       0002
    SXLXLENO       0008
    SXLXLFLG       0000
    SXLXLHLD       0000 80
    SXLXLMSK       000C
    SXLXLNAV       0000 C0
    SXLXLOCK       0000
    SXLXLSEQ       0004
    SXLXLSPD       0000 40
    SXLXLSQT       0014
    SXLXLSQTL      0016
    SXLXLSZB       0018 00000020
    SXLXLSZD       0018 00000004
    SXLXLWD1       0000
    SXLXLWD2       0004

This information is based on z/VM 7.2.0 Last updated on 24 Jun 2020 at 09:31:13 EDT.
Copyright IBM Corporation, 1990, 2020