VMS Help System Services, $CREATE GPFN (Alpha Only)  *Conan The Librarian (sorry for the slow response - running on an old VAX)

    On Alpha 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 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)
    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)
    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$M_GBL     Pages form a global section. By default, this flag
                  is always present in this service and cannot be
                  disabled.
    SEC$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_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 Compaq 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.