Upgrading Privileged-Code Applications on OpenVMS Alpha and
OpenVMS I64 Systems
A.9 I/O Request Packet Extension (IRPE)
This section describes the additions and changes to cells in the I/O Request
Packet Extension (IRPE) structure. An IRPE structure can contain additional
driver-specific information that needs to be associated with an IRP. It can
also be used to manage additional buffers that are locked down for direct I/O.
If the IRP$M_EXTEND bit is set inirp$l_sts then
theirp$l_extend cell contains a pointer to an
associated IRPE structure. Similarly, if the IRPE$M_EXTEND bit is set in theirpe$l_sts cell,
then theirpe$l_extend cell contains a pointer
to another IRPE. In general, if there is an IRPE cell with the nameirpe$Xand
an IRP cell with the nameirp$X, then the cells
must be at the same offsets such that the IRP and the IRPE can be used interchangeably
in contexts that depend only on these common cells.
Currently, a single IRPE structure can be used to keep track of two separate
regions of locked down pages. The new IRPE structure can only manage a single
region of locked down pages and contains a single fixed-size primary DIOBM
structure for that purpose (see Table A-10).
Table A-10 IRPE Changes
| Field |
Type |
Comments |
| irpe$b_rmod |
unsigned char |
Requestor's access mode. This corresponds to the irp$b_rmod cell.
The space for this IRPE cell was reserved but the cell was not previously
formally defined. The addition of this cell facilitates the usage of an
IRPE with the EXE_STD$READLOCK routines because the irpe$b_rmod cell
is one of the required implicit inputs. |
| irpe$l_oboff |
unsigned int |
Original byte offset into first page for buffer locked into memory.
This corresponds to the irp$l_oboff cell
that was added to the IRP on OpenVMS Alpha but was not formally defined
in the IRPE. This corrects that omission. |
| irpe$q_driver_p0 |
int64 |
Available for use by driver. This cell is overlaid on what was previously
filler space. |
| irpe$l_driver_p0 |
int |
Available for use by driver. This cell is overlaid on the low-order
32-bits of irpe$q_driver_p0 . |
| irpe$l_driver_p1 |
int |
Available for use by driver. This cell is overlaid on the high-order
32-bits of irpe$q_driver_p0 . |
| irpe$q_driver_p2 |
int64 |
Available for use by driver. This cell is overlaid on what was previously
filler space. |
| irpe$l_driver_p2 |
int |
Available for use by driver. This cell is overlaid on the low-order
32-bits of irpe$q_driver_p2 . |
| irpe$l_driver_p3 |
int |
Available for use by driver. This cell is overlaid on the high-order
32-bits of irpe$q_driver_p2 . |
| irpe$pq_va_pte |
PTE_PQ |
A 64-bit pointer to the actual PTEs that map the user buffer. If the
user buffer is not in shared system space, then this PTE virtual address
is only valid in the caller's process context. |
| irpe$l_svapte |
PTE * |
A 32-bit pointer to a copy of the PTEs that map the user buffer. If
zero, then no PTEs have been locked for this request. This cell replaces
the irpe$l_svapte1 cell. |
| irpe$l_svapte1 |
- |
This cell has been removed. It is replaced by the irpe$l_svapte cell. |
| irpe$l_bcnt |
unsigned int |
Byte count for buffer locked into memory. This cell replaces the irpe$l_bcnt1 cell. |
| irpe$l_bcnt1 |
- |
This cell has been removed. It is replaced by the irpe$l_bcnt cell. |
| irpe$l_boff |
unsigned int |
Byte offset into first page for buffer locked into memory. This cell
replaces the irpe$l_boff1 cell. |
| irpe$l_boff1 |
- |
This cell has been removed. It is replaced by the irpe$l_boff cell. |
| irpe$r_diobm |
DIOBM |
Embedded fixed-size primary "direct I/O buffer map" structure. This
embedded DIOBM structure is valid if and only if the irpe$l_svapte cell
contains a non-zero value. See Section
A.6 for a complete description of the DIOBM structure. |
| irpe$l_svapte2 |
- |
This cell has been removed. It was used to contain a pointer to the
first PTE for a second buffer that was locked into memory. If zero, then
there was no second buffer. |
| irpe$l_bcnt2 |
- |
This cell has been removed. It was used for the byte count for the second
buffer locked into memory. |
| irpe$l_boff2 |
- |
This cell has been removed. It was used for the byte offset for the
second buffer locked into memory. |
A.10 Process Header (PHD)
This section describes the I/O-specific additions to cells in Process Header
(PHD) structure (see Table A-11).
Table A-11 PHD Structure Changes
| Field |
Type |
Comments |
| phd$l_iorefc |
uint32 |
Number of reasons to keep the PHD resident due to groups of pages locked
for direct I/O. This count is incremented by MMG_STD$IOLOCK_BUF and decremented
by MMG_STD$IOUNLOCK_BUF. On the zero-to-one transition of this cell, the
slot reference count for the process in the PHV$GL_REFCBAS_LW vector is
incremented. On the one-to-zero transition of this cell, the slot reference
count for the process in the PHV$GL_REFCBAS_LW vector is decremented. |
A.11 SCSI-2 Diagnose Buffer (S2DGB)
For information about S2DGB 64-bit addressing support, see the OpenVMS
Alpha Guide to 64-Bit Addressing and VLM Features2.
Note
2 This manual has been archived but
is available on the OpenVMS Documentation CD-ROM.
This information has also been included in the OpenVMS Programming
Concepts Manual, Volume I.
|
A.12 VMS Communications Request Packet (VCRP)
The VCRP structure is the VMS Communications Request Packet that is used by
the OpenVMS LAN driver VMS Communications Interface (VCI). A VCRP is used to
transfer data between an upper- and lower-level VCM.
The VCRP is designed so that it can be used as an ACB by an upper-level VCM.
Therefore, the VCRP has been enhanced such that it can be used either as an
ACB or ACB64 structure by an upper-level VCM. This allows upper-level VCMs
the flexibility of providing 64-bit AST support at some time in the future
without requiring another VCRP change and the forced recompilation of all VCMs
(see Table A-12).
Table A-12 VCRP Structure Changes
| Field |
Type |
Comments |
| vcrp$v_acb_flags_valid |
bit |
This is a new bit in the vcrp$b_rmod cell
that corresponds to the acb$v_flags_valid bit.
This bit is available for the exclusive use of upper-level VCMs. |
| vcrp$l_acb64x_offset |
int |
Offset to the ACB64X structure embedded in this VCRP. This cell corresponds
to the acb$l_acb64x cell and is overlaid
on vcrp$l_ast . This cell is available
for the exclusive use of upper-level VCMs. |
| vcrp$l_acb_flags |
unsigned int |
This cell corresponds to the acb$l_flags cell
and is overlaid on the first longword of the existing fork block filler
space in the VCRP. This cell is available for the exclusive use of upper-level
VCMs. |
| vcrp$l_thread_id |
int |
This cell corresponds to the acb$l_thread_pid cell
and is on the second longword of the existing fork block filler space in
the VCRP. Reserved for use by the Kernel Threads project. |
| vcrp$pq_acb64_ast |
VOID_FUNC_PQ |
This cell corresponds to the acb64$pq_ast cell.
This cell is available for the exclusive use of upper-level VCMs. |
| vcrp$q_acb64_astprm |
int64 |
This cell corresponds to the acb64$q_astprm cell.
This cell is available for the exclusive use of upper-level VCMs. |
| vcrp$q_user_thread_id |
uint64 |
Unique user thread identifier. Corresponds to the acb64$q_user_thread_id cell.
This cell is available for the exclusive use of upper-level VCMs. |
| vcrp$pq_buffer_addr64 |
VOID_PQ |
64-bit buffer address. This cell is available for use by upper-level
VCMs only. Note that this cell does not replace the vcrp$l_buffer_address cell
which continues to be used by lower-level VCMs. |
| vcrp$r_diobm |
DIOBM |
Embedded fixed-size primary "direct I/O buffer map" structure. This
DIOBM structure is available for use by upper-level VCMs that need to lock
down a buffer and provide a value for the vcrp$l_svapte cell. |
| vcrp$t_internal_stack |
char[220] |
This existing internal stack area of 92 bytes has been increased to
220 bytes to reflect the increased size of a DCBE. SYS$PEDRIVER requires
that it can place a DCBE within this stack area. This space is available
for the exclusive use of upper-level VCMs. |
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