HP OpenVMS System Services Reference Manual

All other bits in the flags argument are reserved for future use by HP and should be specified as 0. The condition value SS$_IVSECFLG is returned if any undefined bits are set or if an invalid combination of flags is set.

return_va_64

OpenVMS usage:	address
type:	quadword address
access:	write only
mechanism:	by 32- or 64-bit reference

The lowest process virtual address into which the global demand-zero section was mapped. The return_va_64 argument is the 32- or 64-bit virtual address of a naturally aligned quadword into which the service returns the virtual address.

If a shared page table region is specified by the region_id_64 argument and the SEC$M_EXPREG flag is set, the returned virtual address is aligned to a CPU-specific page table page boundary.

return_length_64

OpenVMS usage:	byte count
type:	quadword (unsigned)
access:	write only
mechanism:	by 32- or 64-bit reference

The 32- or 64-bit virtual address of a naturally aligned quadword into which the service returns the length of the virtual address range mapped in bytes.

start_va_64

OpenVMS usage:	address
type:	quadword address
access:	read only
mechanism:	by value

The starting virtual address to map the memory-resident global section. The specified virtual address must be a CPU-specific page aligned address. If the flag SEC$M_EXPREG is specified, the start_va_64 argument must not be specified or must be specified as 0. If SEC$M_EXPREG is set and the start_va_64 argument is nonzero, the condition value SS$_IVSECFLG is returned.

If SEC$M_EXPREG is clear, start_va_64 is nonzero, and a shared page table region is specified, the specified starting address must be aligned to a natural page table page boundary; otherwise, the condition value SS$_VA_NOTPAGALGN is returned.

If the /ALLOCATE qualifier was specified when the memory-resident global section was registered in the Reserved Memory Registry and start_va_64 is aligned to a multiple of CPU-specific pages appropriate for taking advantage of granularity hints then granularity hints are used to map to the global section:

On Alpha systems, granularity hints mean multiples of pages, regardless of page size. The multiples 8, 64, and 512 pages are architected.
On Integrity server systems, OpenVMS initially supports page sizes of 64KB, 256KB, and 4MB instead of granularity hints. Additional pages sizes will be supported in the future.

If the flag VA$M_SHARED_PTS is set and this argument is specified, the specified starting address must be aligned to the larger of a natural page table boundary or to the largest possible page size used to map the section. If the alignment is less than a page table boundary, the $CREATE_REGION_64 service returns an error. If the alignment is less than the largest page size used in the section, an error might be returned when you attempt to map the section.

If you do not specify a starting address, OpenVMS automatically ensures correct alignment.

map_length_64

OpenVMS usage:	byte count
type:	quadword (unsigned)
access:	read only
mechanism:	by value

Length of the memory-resident global section to be mapped. The length specified must be a multiple of CPU-specific pages. If this argument is not specified or is specified as zero, the global file section is mapped up to and including the last page in that section.

If a shared page table region is specified by the region_id_64 argument, map_length_64 must be an even multiple of the number of bytes that can be mapped by a CPU-specific page table page or must include the last page within the global section.

reserved_length_64

OpenVMS usage:	byte count
type:	quadword (unsigned)
access:	write only
mechanism:	32- or 64-bit reference

Length, in bytes, of the global section as currently registered in the Reserved Memory Registry. The reserved_length_64 argument is the 32- or 64-bit virtual address of a naturally aligned quadword into which the service returns the reserved length.

If reserved_length_64 is not specified or is specified as 0, no reserved length is returned to the caller.

If the memory-resident global section is not registered, reserved_length_64 is written with the value 0.

rad_mask

OpenVMS usage:	mask_quadword
type:	quadword (unsigned)
access:	read only
mechanism:	by value

Use the rad_mask argument to specify from which RADs to allocate memory. Currently only one bit may be set. The specified RAD must contain memory. This argument is only a hint. Memory may be obtained from other RADs if no free memory is available at the time of allocation.

The rad_mask argument is considered only if the SEC$M_RAD_HINT flag is specified. Otherwise, this argument is ignored.

On a system that does not support resource affinity domains (RADs), specifying 1 for the rad_mask argument is allowed.

RAD is supported on AlphaServer GS series systems and starting from OpenVMS Version 8.4, support is extended to NUMA capable Integrity servers.

Description

The Create and Map to Global Demand-Zero Section service allows a process to create and map to a memory-resident global demand-zero section. If you set the SEC$M_SHMGS flag, the section is created as a Galaxy-wide global demand-zero section in shared memory.
You must call either the $CREATE_GDZRO service or the $CRMPSC_GDZRO_64 service on each instance where the Galaxy shared memory will be accessed.
Memory-resident or Galaxy-wide global sections contain demand-zero allocation pages that are writable and memory resident. All pages in these types of global section are shared by all processes that map to the global section.
If the $CRMPSC_GDZRO_64 service specifies a global section that already exists, the service maps to it only if it is a memory-resident global section. All pages in the memory-resident global section are shared by all processes that map to the global section.
The global demand-zero pages are always resident in memory and are not backed up by any file on any disk. The global pages are not charged against any page file quota. The process must have the rights identifier VMS$MEM_RESIDENT_USER to create a memory-resident global section; otherwise, the error status SS$_NOMEMRESID is returned.
The pages are always resident in memory and are not backed up by any file on any disk. The pages are not placed into the process's working set list when the process maps to the global section and the virtual memory is referenced by the process. The pages are also not charged against the process's working set quota or against any page-file quota.
Only memory-resident sections can be registered with the Reserved Memory Registry in the SYSMAN facility. Memory for Galaxy-wide shared sections is reserved through appropriate settings of the console environment parameters.
If the memory-resident global section is either not registered in the Reserved Memory Registry or if the /NOALLOCATE qualifier was specified when the global section was registered in the Reserved Memory Registry, invalid global PTEs are written to the global page table and invalid PTEs are placed in the process page table. Physical memory is not allocated until the virtual memory is referenced.
If the global section is registered in the Reserved Memory Registry, the size of the global section need not match the reserved size. If the global section is not registered in the Reserved Memory Registry or if the reserved size is smaller than the size of the global section, the error status SS$_INSFLPGS is returned if there are not enough fluid pages in the system to satisfy the request.
If the /ALLOCATE qualifier was specified when the global section was registered in the Reserved Memory Registry, contiguous, aligned physical pages are preallocated during system initialization for this global section. Valid page table entries are placed in the global page table and in the process page table. If the reserved preallocated memory is smaller than the size of the global section, the error SS$_MRES_PFNSMALL is returned and the global section is not created.
If the memory-resident global section is not registered in the Reserved Memory Registry or if the /PAGE_TABLES qualifier was specified when the global section was registered in the Reserved Memory Registry, shared page tables are created for the global section.
For more information about using the SYSMAN utility to create entries to the Reserved Memory Registry, refer to the HP OpenVMS System Management Utilities Reference Manual.
Shared page tables consume the same internal OpenVMS data structures as a global section. The system parameters GBLPAGES and GBLSECTIONS must account for the additional global pages and the additional global section.
To use the shared page tables associated with a memory-resident global section, you must first create a shared page-table region (with $CREATE_REGION_64). To map to the memory-resident global section using the shared page tables, you must do the following:

Specify a shared page-table region in the region_id_64 argument.
Set the flag SEC$M_EXPREG or provide a CPU-specific page table page aligned virtual address in the start_va_64 argument.
Specify a value for the section_offset_64 argument that is an even multiple of bytes mapped by a CPU-specific page table page or zero.
Specify a value for the map_length_64 argument that is an even multiple of bytes mapped by a CPU-specific page table page or zero, or include the last page of the section.

See the description of the $CREATE_REGION_64 service for information about calculating virtual addresses that are aligned to a CPU-specific page table page boundary.
The memory-resident global section can be mapped with shared page tables or private page tables. The following table lists the factors associated with determining whether the mapping occurs with shared page tables or with private page tables:

Global Section Created with Shared Page Tables Shared Page Table Region Specified by region_id_64 Type of Page Tables Used in Mapping

No No Private

No Yes Private

Yes No Private

Yes Yes Shared

In general, if the flag SEC$M_EXPREG is set, the first free virtual address within the specified region is used to map to the global section.
If the flag SEC$M_EXPREG is set and the region_id_64 argument indicates a shared page table region, the first free virtual address within the specified region is rounded up to a CPU-specific page table page boundary and used to map to the global section.
If the flag SEC$M_EXPREG is set and if the /ALLOCATE qualifier was specified with the SYSMAN command RESERVED_MEMORY ADD for the memory-resident global section, the first free virtual address within the specified region is rounded up to the same virtual alignment as the physical alignment of the preallocated pages and used to map to the global section. Granularity hints are set appropriately for each process private PTE.
In general, if the flag SEC$M_EXPREG is clear, the virtual address in the start_va_64 argument is used to map to the global section.
If the flag SEC$M_EXPREG is clear, the value specified in the start_va_64 argument can determine if the mapping is possible and if granularity hints are used in the private page tables. If a shared page table region is specified by the region_id_64 argument, the virtual address specified by the start_va_64 argument must be on an even CPU-specific page table page boundary or an error is returned by this service. If the region_id_64 argument does not specify a shared page table region and /ALLOCATE was specified with the SYSMAN command RESERVED_MEMORY ADD for this global section, granularity hints are used only if the virtual alignment of start_va_64 is appropriate for the use of granularity hints (either 8-page, 64-page, or 512-page alignment).
Whenever granularity hints are being used within the mapping of a memory-resident global section, if the length_64 argument is not an exact multiple of the alignment factor, lower granularity hints factors are used as appropriate at the higher addressed portion of the global section. If the section_offset_64 argument is specified, a lower granularity hint factor can be used throughout the mapping of the global section to match the physical alignment of the first page mapped.
When you map a Galaxy shared section or a memory resident section that has an associated shared page table section, you have the following options for accessing data:

Table SYS-22 Shared Page Tables
Shared Page Tables Read Only Read and Write

None created Do not set the SEC$M_WRT flag in the map request.
Private page tables will always be used, even if you are specifying a shared page table region into which to map the section.
Set the SEC$M_WRT flag in the map request.
Private page tables will always be used, even if you are specifying a shared page table region into which to map the section.

Write access Do not set the SEC$M_WRT flag in the map request.
Ensure that private page tables will be used. Do not specify a shared page table region into which to map the section. If you do, the error status SS$_IVSECFLG is returned.
Set the SEC$M_WRT flag in the map request.
The shared page table section will be used for mapping if you specify a shared page table region into which to map the section.

Read access Do not set the SEC$M_WRT flag in the map request. The shared page table section will be used for mapping if you specify a shared page table region into which to map the section. Set the SEC$M_WRT flag in the map request. Ensure that private page tables will be used. Do not specify a shared page table region into which to map the section. If you do, the error status SS$_IVSECFLG is returned.

Notes
Shared page tables for Galaxy shared sections are also implemented as Galaxy shared sections. This implies that they allow either read access only on all OpenVMS instances connected to this section or read and write access on all instances. The setting of the SEC$M_READ_ONLY_SHPT flag as requested by the first instance to create the section is used on all instances.
Using the $CRMPSC_GDZRO_64 service always implies that the SEC$M_WRT flag is set and that you want to map the section for writing. If you want to use this service to create a section with shared page tables for read only access, you must use private page tables and you cannot specify a shared page table region into which to map the section.

If the condition value SS$_ACCVIO is returned by this service, a value cannot be returned in the memory locations pointed to by the return_va_64 and return_length_64 arguments and, if specified as a nonzero value, the reserved_length_64 argument.
If a condition value other than SS$_ACCVIO is returned, the returned address and returned length indicate the pages that were successfully mapped before the error occurred. If no pages were mapped, the return_va_64 argument contains the value --1.
If the service returns an error status value other than SS$_INSFLPGS or SS$_MRES_PFNSMALL, a value is not returned in the reserved_length_64 argument.
If the service returns a successful condition value or if SS$_INSFLPGS or SS$_MRES_PFNSMALL is returned and the reserved_length_64 argument is specified as a nonzero address, the length in bytes of the global section as registered in the Reserved Memory Registry is returned in the reserved_length_64 argument.
Required Privileges

To create a global section, the process must have the following privileges:

SYSGBL privilege to create a system global section (if flag SEC$M_SYSGBL is set)
PRMGBL privilege to create a permanent global section
VMS$MEM_RESIDENT_USER rights identifier to create a memory-resident section
SHMEM privilege on OpenVMS Galaxy systems to create an object in Galaxy shared memory

Required Quota

If private page tables are used to map to the memory-resident global section, the working set limit quota (WSQUOTA) of the process must be sufficient to accommodate the increased size of the process page tables required by the increase in virtual address space.
If private page tables are used to map to the memory-resident global section, the page file quota (PGFLQUOTA) of the process must be sufficient to accommodate the increased size of the process page tables required by the increase in virtual address space.
Related Services

$CREATE_GDZRO, $CREATE_GPFILE, $CREATE_REGION_64, $CRMPSC, $CRMPSC_FILE_64, $CRMPSC_GFILE_64, $CRMPSC_GPFN_64, $CRMPSC_PFN_64, $DELETE_REGION_64, $DELTVA_64, $DGBLSC, $LCKPAG_64, $LKWSET_64, $MGBLSC_64, $PURGE_WS, $SETPRT_64, $ULKPAG_64, $ULWSET_64, $UPDSEC_64, $UPDSEC_64W

Global Section Created with Shared Page Tables	Shared Page Table Region Specified by region_id_64	Type of Page Tables Used in Mapping
No	No	Private
No	Yes	Private
Yes	No	Private
Yes	Yes	Shared

**Table SYS-22 Shared Page Tables**
Shared Page Tables	Read Only	Read and Write
None created	Do not set the SEC$M_WRT flag in the map request. Private page tables will always be used, even if you are specifying a shared page table region into which to map the section.	Set the SEC$M_WRT flag in the map request. Private page tables will always be used, even if you are specifying a shared page table region into which to map the section.
Write access	Do not set the SEC$M_WRT flag in the map request. Ensure that private page tables will be used. Do not specify a shared page table region into which to map the section. If you do, the error status SS$_IVSECFLG is returned.	Set the SEC$M_WRT flag in the map request. The shared page table section will be used for mapping if you specify a shared page table region into which to map the section.
Read access	Do not set the SEC$M_WRT flag in the map request. The shared page table section will be used for mapping if you specify a shared page table region into which to map the section.	Set the SEC$M_WRT flag in the map request. Ensure that private page tables will be used. Do not specify a shared page table region into which to map the section. If you do, the error status SS$_IVSECFLG is returned.

Condition Values Returned

SS$_NORMAL The service completed successfully. The specified global section already exists and has been mapped.

SS$_CREATED The service completed successfully. The global section has been created.

SS$_CREATED_SHPT Global section has been created with shared page tables.

SS$_ACCVIO The gs_name_64 argument cannot be read by the caller, or the return_va_64 or return_length_64 argument cannot be written by the caller.

SS$_BADRAD The specified RAD contains no memory, or if the specified RAD is greater than or equal to the maximum number of RADs on the system.

SS$_EXPGFLQUOTA The process's page file quota is not large enough to accommodate the increased virtual address space.

SS$_GBLSEC_MISMATCH Global section type mismatch. The specified global section was found; however, it is not a memory-resident section.

SS$_GPTFULL There is no more room in the system global page table to set up page table entries for the global section or for the shared page tables.

SS$_GSDFULL There is no more room in the system space allocated to maintain control information for global sections.

SS$_INSFLPGS Insufficient fluid pages available.

SS$_INSFRPGS Insufficient free shared pages or private pages.

SS$_INSFWSL The process's working set limit is not large enough to accommodate the increased virtual address space.

SS$_INSF_SHM_REG The Galaxy shared memory code has run out of internal SHM_REG data structures. You need to increase the system parameter GLX_SHM_REG and reboot all Galaxy instances with this larger parameter value.

SS$_INV_SHMEM Shared memory is not valid.

SS$_IVACMODE The specified access mode is greater than PSL$_USER, or the caller's mode is less privileged than the create mode associated with the region.

SS$_IVLOGNAM The specified global section name has a length of 0 or has more than 43 characters.

SS$_IVPROTECT The protection argument format is invalid.

SS$_IVREGID An invalid region ID was specified.

SS$_IVSECFLG An invalid flag, a reserved flag, or an invalid combination of flags was specified.

SS$_IVSECIDCTL The match control field of the global section identification is invalid.

SS$_LEN_NOTPAGMULT The length_64 argument is not a multiple of CPU-specified pages. Or, if a shared page table region is specified by the region_id_64 argument, the map_length_64 argument is not a multiple of CPU-specific page table pages.

SS$_LOCK_TIMEOUT An OpenVMS Galaxy lock timed out.

SS$_MRES_PFNSMALL Preallocated, contiguous, aligned physical memory specified in the Reserved Memory Registry is smaller than the length specified for the memory-resident global section by the length_64 argument.

SS$_NOBREAK An OpenVMS Galaxy lock is held by another node and was not broken.

SS$_NOMEMRESID The process attempted to create a memory-resident section, but was not holding the right identifier VMS$MEM_RESIDENT_USER.

SS$_NOPRMGBL The process does not have the privileges to create or delete a permanent group global section (PRMGBL).

SS$_NOSYSGBL The process does not have the privileges to create or delete a system global section (SYSGBL).

SS$_OFF_NOTPAGALGN The section_offset_64 argument is not CPU-specific page aligned. Or, if a shared page table region is specified by the region_id_64 argument, the section_offset_64 argument is not CPU-specific page table page aligned.

SS$_OFFSET_TOO_BIG The section_offset_64 argument specified is beyond the logical end-of-file.

SS$_PAGNOTINREG A page in the specified input address range is not within the specified region.

SS$_PAGOWNVIO A page in the specified input address range is owned by a more privileged access mode.

SS$_REGISFULL The specified virtual region is full; no space is available in the region for the pages created to contain the mapped section.

SS$_SECREFOVF The maximum number of references for a global section has been reached (2,147,483,647).

SS$_SECTBLFUL There are no entries available in the system global section table for the global section or for the shared page tables.

SS$_TOOMANYLNAM The logical name translation of the gs_name_64 argument exceeded the allowed depth of 10.

SS$_VA_IN_USE A page in the specified input address range is already mapped and the flag SEC$M_NO_OVERMAP is set, or a page in the specified input address range is in another region, in system space, or inaccessible; or, the existing underlying page cannot be deleted because it is associated with a buffer object.

SS$_VA_NOTPAGALGN The start_va_64 argument is not CPU-specific page aligned. Or, if a shared page table region is specified by the region_id_64 argument, the start_va_64 argument is not CPU-specific page table page aligned.

Contents

Index

SS$_NORMAL	The service completed successfully. The specified global section already exists and has been mapped.
SS$_CREATED	The service completed successfully. The global section has been created.
SS$_CREATED_SHPT	Global section has been created with shared page tables.
SS$_ACCVIO	The gs_name_64 argument cannot be read by the caller, or the return_va_64 or return_length_64 argument cannot be written by the caller.
SS$_BADRAD	The specified RAD contains no memory, or if the specified RAD is greater than or equal to the maximum number of RADs on the system.
SS$_EXPGFLQUOTA	The process's page file quota is not large enough to accommodate the increased virtual address space.
SS$_GBLSEC_MISMATCH	Global section type mismatch. The specified global section was found; however, it is not a memory-resident section.
SS$_GPTFULL	There is no more room in the system global page table to set up page table entries for the global section or for the shared page tables.
SS$_GSDFULL	There is no more room in the system space allocated to maintain control information for global sections.
SS$_INSFLPGS	Insufficient fluid pages available.
SS$_INSFRPGS	Insufficient free shared pages or private pages.
SS$_INSFWSL	The process's working set limit is not large enough to accommodate the increased virtual address space.
SS$_INSF_SHM_REG	The Galaxy shared memory code has run out of internal SHM_REG data structures. You need to increase the system parameter GLX_SHM_REG and reboot all Galaxy instances with this larger parameter value.
SS$_INV_SHMEM	Shared memory is not valid.
SS$_IVACMODE	The specified access mode is greater than PSL$_USER, or the caller's mode is less privileged than the create mode associated with the region.
SS$_IVLOGNAM	The specified global section name has a length of 0 or has more than 43 characters.
SS$_IVPROTECT	The protection argument format is invalid.
SS$_IVREGID	An invalid region ID was specified.
SS$_IVSECFLG	An invalid flag, a reserved flag, or an invalid combination of flags was specified.
SS$_IVSECIDCTL	The match control field of the global section identification is invalid.
SS$_LEN_NOTPAGMULT	The length_64 argument is not a multiple of CPU-specified pages. Or, if a shared page table region is specified by the region_id_64 argument, the map_length_64 argument is not a multiple of CPU-specific page table pages.
SS$_LOCK_TIMEOUT	An OpenVMS Galaxy lock timed out.
SS$_MRES_PFNSMALL	Preallocated, contiguous, aligned physical memory specified in the Reserved Memory Registry is smaller than the length specified for the memory-resident global section by the length_64 argument.
SS$_NOBREAK	An OpenVMS Galaxy lock is held by another node and was not broken.
SS$_NOMEMRESID	The process attempted to create a memory-resident section, but was not holding the right identifier VMS$MEM_RESIDENT_USER.
SS$_NOPRMGBL	The process does not have the privileges to create or delete a permanent group global section (PRMGBL).
SS$_NOSYSGBL	The process does not have the privileges to create or delete a system global section (SYSGBL).
SS$_OFF_NOTPAGALGN	The section_offset_64 argument is not CPU-specific page aligned. Or, if a shared page table region is specified by the region_id_64 argument, the section_offset_64 argument is not CPU-specific page table page aligned.
SS$_OFFSET_TOO_BIG	The section_offset_64 argument specified is beyond the logical end-of-file.
SS$_PAGNOTINREG	A page in the specified input address range is not within the specified region.
SS$_PAGOWNVIO	A page in the specified input address range is owned by a more privileged access mode.
SS$_REGISFULL	The specified virtual region is full; no space is available in the region for the pages created to contain the mapped section.
SS$_SECREFOVF	The maximum number of references for a global section has been reached (2,147,483,647).
SS$_SECTBLFUL	There are no entries available in the system global section table for the global section or for the shared page tables.
SS$_TOOMANYLNAM	The logical name translation of the gs_name_64 argument exceeded the allowed depth of 10.
SS$_VA_IN_USE	A page in the specified input address range is already mapped and the flag SEC$M_NO_OVERMAP is set, or a page in the specified input address range is in another region, in system space, or inaccessible; or, the existing underlying page cannot be deleted because it is associated with a buffer object.
SS$_VA_NOTPAGALGN	The start_va_64 argument is not CPU-specific page aligned. Or, if a shared page table region is specified by the region_id_64 argument, the start_va_64 argument is not CPU-specific page table page aligned.