On Alpha and Integrity server systems, creates a permanent page
frame section to which processes can map.
This service accepts 64-bit addresses.
Format
SYS$CREATE_GPFN gs_name_64 ,ident_64 ,prot ,start_pfn
,page_count ,acmode ,flags
C Prototype
int sys$create_gpfn (void *gs_name_64, struct _secid
*ident_64, unsigned int prot, unsigned
int start_pfn, unsigned int page_count,
unsigned int acmode, unsigned int flags);
1 – Arguments
gs_name_64
OpenVMS usage:section_name
type: character-coded text string
access: read only
mechanism: by 32- or 64-bit descriptor-fixed-length string
descriptor
Name of the global section. The gs_name_64 argument is the 32-
or 64-bit virtual address of a naturally aligned 32- or 64-bit
string descriptor pointing to this name string.
ident_64
OpenVMS usage:section_id
type: quadword (unsigned)
access: read only
mechanism: by 32- or 64-bit reference
Identification value specifying the version number of a global
section. The ident_64 argument is a quadword containing three
fields. The ident_64 argument is the 32- or 64-bit virtual
address of a naturally aligned quadword that contains the
identification value.
The first longword specifies the matching criteria in its low-
order two bits.
The valid values, symbolic names by which they can be specified,
and their meanings are as follows:
Symbolic
Value Name Match Criteria
0 SEC$K_MATALL Match all versions of the section.
1 SEC$K_MATEQU Match only if major and minor
identifications match.
2 SEC$K_MATLEQ Match if the major identifications are
equal and the minor identification of the
mapper is less than or equal to the minor
identification of the global section.
If you specify the ident_64 argument as 0, the version number and
match control fields default to 0.
The version number is in the second longword. The version number
contains two fields: a minor identification in the low-order 24
bits and a major identification in the high-order 8 bits. You
can assign values for these fields by installation convention to
differentiate versions of global sections. If no version number
is specified when a section is created, processes that specify a
version number when mapping cannot access the global section.
prot
OpenVMS usage:file_protection
type: longword (unsigned)
access: read only
mechanism: by value
Protection to be applied to the global page frame section. The
mask contains four 4-bit fields. Bits are read from right to left
in each field.
Refer to the VSI OpenVMS System Services Reference Manual to view
the diagram depicting the mask.
Cleared bits indicate that read, write, execute, and delete
access, in that order, are granted to the particular category
of user. Only read, write, and execute access are meaningful
for section protection. Delete access bits are ignored. Read
access also grants execute access for those situations where
execute access applies. If zero is specified, read access and
write access are granted to all users.
start_pfn
OpenVMS usage:page frame number
type: longword (unsigned) on Alpha, quadword (unsigned)
on Integrity servers
access: read only
mechanism: by value
The CPU-specific page frame number where the section begins in
memory.
page_count
OpenVMS usage:CPU-specific page count
type: longword (unsigned) on Alpha, quadword (unsigned)
on Integrity servers
access: read only
mechanism: by value
Length of the page frame section in CPU-specific pages.
acmode
OpenVMS usage:access_mode
type: longword (unsigned)
access: read only
mechanism: by value
Access mode that is to be the owner of the pages created during
the mapping. The acmode argument is a longword containing the
access mode.
The $PSLDEF macro in STARLET.MLB and the file PSLDEF.H in
SYS$STARLET_C.TLB define the following symbols and their values
for the four access modes:
Value Symbolic Name Access Mode
0 PSL$C_KERNEL Kernel
1 PSL$C_EXEC Executive
2 PSL$C_SUPER Supervisor
3 PSL$C_USER User
flags
OpenVMS usage:mask_longword
type: longword (unsigned)
access: read only
mechanism: by value
Flag mask specifying the characteristics of the page frame
section to be created. The flags argument is a longword bit
vector in which each bit corresponds to a flag. The $SECDEF macro
and the SECDEF.H file define a symbolic name for each flag. You
construct the flags argument by performing a logical OR operation
on the symbol names for all desired flags.
The following table describes the flags that are valid for the
$CREATE_GPFN service:
Flag Description
SEC$M_ARGS64 Indicates that all parameters, specifically start_
pfn and page_count, are passed as 64-bit numbers.
This flag is ignored on OpenVMS Alpha but must be
set on Integrity server systems. If the flag is
not set on Integrity servers, the error code SS$_
IVSECFLG is returned.
SEC$M_GBL Pages form a global section. By default, this flag
is always present in this service and cannot be
disabled.
SEC$M_PERM Global section is permanent. By default, this flag
is always present in this service and cannot be
disabled.
SEC$M_PFNMAP Pages form a page frame section. By default, this
flag is always present in this service and cannot
be disabled.
SEC$M_SYSGBL Pages form a system global page frame section.
By default, pages form a group global page frame
section.
SEC$M_ Flag that must be set when a PFN-mapped section
UNCACHED is created if this section must be treated as
uncached memory. Flag is ignored on Alpha systems;
it applies only to Integrity server systems.
SEC$M_WRT Pages form a read/write section. By default, pages
form a read-only section.
All other bits in the flags argument are reserved for future
use by VSI and should be specified as 0. The condition value
SS$_IVSECFLG is returned if any undefined bits are set or if
an illegal combination of flags is set.