Updated: 11 December 1998

OpenVMS Alpha Guide to 64-Bit Addressing and VLM Features

This example program demonstrates the 64-bit region creation and deletion system services. It uses SYS$CREATE_REGION_64 to create a region and then uses SYS$EXPREG_64 to allocate virtual addresses within that region. The virtual address space and the region are deleted by calling SYS$DELETE_REGION_64.

/* ***************************************************************************** * * Copyright © Digital Equipment Corporation, 1995 All Rights Reserved. * Unpublished rights reserved under the copyright laws of the United States. * * The software contained on this media is proprietary to and embodies the * confidential technology of Digital Equipment Corporation. Possession, use, * duplication or dissemination of the software and media is authorized only * pursuant to a valid written license from Digital Equipment Corporation. * * RESTRICTED RIGHTS LEGEND Use, duplication, or disclosure by the U.S. * Government is subject to restrictions as set forth in Subparagraph * (c)(1)(ii) of DFARS 252.227-7013, or in FAR 52.227-19, as applicable. * ***************************************************************************** /* This program creates a region in P2 space using the region creation service and then creates VAs within that region. The intent is to demonstrate the use of the region services and how to allocate virtual addresses within a region. The program also makes use of 64-bit descriptors and uses them to format return values into messages with the aid of SYS$GETMSG. To build and run this program type: $ CC/POINTER_SIZE=32/STANDARD=RELAXED/DEFINE=(__NEW_STARLET=1) - REGIONS.C $ LINK REGIONS.OBJ $ RUN REGIONS.EXE */ #include <descrip.h> /* Descriptor Definitions */ #include <far_pointers.h> /* Long Pointer Definitions */ #include <gen64def.h> /* Generic 64-bit Data Type Definition */ #include <iledef.h> /* Item List Entry Definitions */ #include <ints.h> /* Various Integer Typedefs */ #include <iosbdef.h> /* I/O Status Block Definition */ #include <psldef.h> /* PSL$ Constants */ #include <ssdef.h> /* SS$_ Message Codes */ #include <starlet.h> /* System Service Prototypes */ #include <stdio.h> /* printf */ #include <stdlib.h> /* malloc, free */ #include <string.h> /* memset */ #include <syidef.h> /* $GETSYI Item Code Definitions */ #include <vadef.h> /* VA Creation Flags and Constants */ /* Module-wide constants and macros. */ #define BUFFER_SIZE 132 #define HW_NAME_LENGTH 32 #define PAGELET_SIZE 512 #define REGION_SIZE 128 #define good_status(code) ((code) & 1) /* Module-wide Variables */ int page_size; $DESCRIPTOR64 (msgdsc, ""); /* Function Prototypes */ int get_page_size (void); static void print_message (int code, char *string); main (int argc, char **argv) { int i, status; uint64 length_64, master_length_64, return_length_64; GENERIC_64 region_id_64; VOID_PQ master_va_64, return_va_64; /* Get system page size, using SYS$GETSYI. */ status = get_page_size (); if (!good_status (status)) return (status); /* Get a buffer for the message descriptor. */ msgdsc.dsc64$pq_pointer = malloc (BUFFER_SIZE); printf ("Message Buffer Address = %016LX\n\n", msgdsc.dsc64$pq_pointer); /* Create a region in P2 space. */ length_64 = REGION_SIZE*page_size; status = sys$create_region_64 ( length_64, /* Size of Region to Create */ VA$C_REGION_UCREATE_UOWN, /* Protection on Region */ 0, /* Allocate in Region to Higher VAs */ &region_id_64, /* Region ID */ &master_va_64, /* Starting VA in Region Created */ &master_length_64); /* Size of Region Created */ if (!good_status (status)) { print_message (status, "SYS$CREATE_REGION_64"); return (status); } printf ("\nSYS$CREATE_REGION_64 Created this Region: %016LX - %016LX\n", master_va_64, (uint64) master_va_64 + master_length_64 - 1); /* Create virtual address space within the region. */ for (i = 0; i < 3; ++i) { status = sys$expreg_64 ( &region_id_64, /* Region to Create VAs In */ page_size, /* Number of Bytes to Create */ PSL$C_USER, /* Access Mode */ 0, /* Creation Flags */ &return_va_64, /* Starting VA in Range Created */ &return_length_64); /* Number of Bytes Created */ if (!good_status (status)) { print_message (status, "SYS$EXPREG_64"); return status; } printf ("Filling %016LX - %16LX with %0ds.\n", return_va_64, (uint64) return_va_64 + return_length_64 - 1, i); memset (return_va_64, i, page_size); } /* Return the virtual addresses created within the region, as well as the region itself. */ printf ("\nReturning Master Region: %016LX - %016LX\n", master_va_64, (uint64) master_va_64 + master_length_64 - 1); status = sys$delete_region_64 ( &region_id_64, /* Region to Delete */ PSL$C_USER, /* Access Mode */ &return_va_64, /* VA Deleted */ &return_length_64); /* Length Deleted */ if (good_status (status)) printf ("SYS$DELETE_REGION_64 Deleted VAs Between: %016LX - %016LX\n", return_va_64, (uint64) return_va_64 + return_length_64 - 1); else { print_message (status, "SYS$DELTE_REGION_64"); return (status); } /* Return message buffer. */ free (msgdsc.dsc64$pq_pointer); } /* This routine obtains the system page size using SYS$GETSYI. The return value is recorded in the module-wide location, page_size. */ int get_page_size () { int status; IOSB iosb; ILE3 item_list [2]; /* Fill in SYI item list to retrieve the system page size. */ item_list[0].ile3$w_length = sizeof (int); item_list[0].ile3$w_code = SYI$_PAGE_SIZE; item_list[0].ile3$ps_bufaddr = &page_size; item_list[0].ile3$ps_retlen_addr = 0; item_list[1].ile3$w_length = 0; item_list[1].ile3$w_code = 0; /* Get the system page size. */ status = sys$getsyiw ( 0, /* EFN */ 0, /* CSI address */ 0, /* Node name */ &item_list, /* Item list */ &iosb, /* I/O status block */ 0, /* AST address */ 0); /* AST parameter */ if (!good_status (status)) { print_message (status, "SYS$GETJPIW"); return (status); } if (!good_status (iosb.iosb$w_status)) { print_message (iosb.iosb$w_status, "SYS$GETJPIW IOSB"); return (iosb.iosb$w_status); } return SS$_NORMAL; } /* This routine takes the message code passed to the routine and then uses SYS$GETMSG to obtain the associated message text. That message is then printed to stdio along with a user-supplied text string. */ #pragma inline (print_message) static void print_message (int code, char *string) { msgdsc.dsc64$q_length = BUFFER_SIZE; sys$getmsg ( code, /* Message Code */ (unsigned short *) &msgdsc.dsc64$q_length, /* Returned Length */ &msgdsc, /* Message Descriptor */ 15, /* Message Flags */ 0); /* Optional Parameter */ *(msgdsc.dsc64$pq_pointer+msgdsc.dsc64$q_length) = '\0'; printf ("Call to %s returned: %s\n", string, msgdsc.dsc64$pq_pointer); }

This example program demonstrates the memory management VLM features described in Chapter 4.

/* ***************************************************************************** * * Copyright © Digital Equipment Corporation, 1996 All Rights Reserved. * Unpublished rights reserved under the copyright laws of the United States. * * The software contained on this media is proprietary to and embodies the * confidential technology of Digital Equipment Corporation. Possession, use, * duplication or dissemination of the software and media is authorized only * pursuant to a valid written license from Digital Equipment Corporation. * * RESTRICTED RIGHTS LEGEND Use, duplication, or disclosure by the U.S. * Government is subject to restrictions as set forth in Subparagraph * (c)(1)(ii) of DFARS 252.227-7013, or in FAR 52.227-19, as applicable. * ***************************************************************************** /* This program creates and maps to a memory-resident global section using shared page tables. The program requires a reserved memory entry (named In_Memory_Database) in the Reserved Memory Registry. The entry in the registry is created using SYSMAN as follows: $ MCR SYSMAN SYSMAN> RESERVED_MEMORY ADD "In_Memory_Database"/ALLOCATE/PAGE_TABLES - /ZERO/SIZE=64/GROUP=100 The above command creates an entry named In_Memory_Database that is 64M bytes in size and requests that the physical memory be allocated during system initialization. This enables the physical memory to be mapped with granularity hints by the SYS$CRMPSC_GDZRO_64 system service. It also requests that physical memory be allocated for page tables for the named entry, requests the allocated memory be zeroed, and requests that UIC group number 100 be associated with the entry. Once the entry has been created with SYSMAN, the system must be re-tuned with AUTOGEN. Doing so allows AUTOGEN to re-calculate values for SYSGEN parameters that are sensitive to changes in physical memory sizes. (Recall that the Reserved Memory Registry takes physical pages away from the system.) Once AUTOGEN has been run, the system must be rebooted. Using the following commands to compile and link this program: $ CC/POINTER_SIZE=32 shared_page_tables_example $ LINK shared_page_tables_example Since 64-bit virtual addresses are used by this program, a Version 5.2 DEC C compiler or later is required to compile it. */ #define __NEW_STARLET 1 #include <DESCRIP> #include <FAR_POINTERS> #include <GEN64DEF> #include <INTS> #include <PSLDEF> #include <SECDEF> #include <SSDEF> #include <STARLET> #include <STDIO> #include <STDLIB> #include <STRING> #include <VADEF> #define bad_status(status) (((status) & 1) != 1) #define ONE_MEGABYTE 0x100000  main () { int status; $DESCRIPTOR (section_name, "In_Memory_Database"); uint32 region_flags = VA$M_SHARED_PTS, /* Shared PT region. */ section_flags = SEC$M_EXPREG; uint64 mapped_length, requested_size = 64*ONE_MEGABYTE, section_length = 64*ONE_MEGABYTE, region_length; GENERIC_64 region_id; VOID_PQ mapped_va, region_start_va; printf ("Shared Page Table Region Creation Attempt: Size = %0Ld\n", requested_size); /* Create a shared page table region. */ status = sys$create_region_64 ( requested_size, /* Size in bytes of region */ VA$C_REGION_UCREATE_UOWN, /* Region VA creation and owner mode */ region_flags, /* Region Flags: shared page tables */ &region_id, /* Region ID */ &region_start_va, /* Starting VA for region */ &region_length); /* Size of created region */ if (bad_status (status)) { printf ("ERROR: Unable to create region of size %16Ld\n\n", requested_size); return; } printf ("Shared Page Table Region Created: VA = %016LX, Size = %0Ld\n\n", region_start_va, region_length); /* Create and map a memory-resident section with shared page tables into the shared page table region. */ printf ("Create and map to section %s\n", section_name.dsc$a_pointer); status = sys$crmpsc_gdzro_64 ( &section_name, /* Section name */ 0, /* Section Ident */ 0, /* Section protection */ section_length, /* Length of Section */ &region_id, /* RDE */ 0, /* Section Offset; map entire section */ PSL$C_USER, /* Access Mode */ section_flags, /* Section Creation Flags */ &mapped_va, /* Return VA */ &mapped_length); /* Return Mapped Length */ if (bad_status (status)) printf ("ERROR: Unable to Create and Map Section %s, status = %08x\n\n", section_name.dsc$a_pointer, status); else { printf ("Section %s created, Section Length = %0Ld\n", section_name.dsc$a_pointer, section_length); printf (" Mapped VA = %016LX, Mapped Length = %0Ld\n\n", mapped_va, mapped_length); } /* Delete the shared page table. This will cause the mapping to the section and the section itself to be deleted. */ printf ("Delete the mapping to the memory-resident global section"); printf (" and the shared\n page table region.\n"); status = sys$delete_region_64 ( &region_id, PSL$C_USER, &region_start_va, &region_length); if (bad_status (status)) printf ("ERROR: Unable to delete shared page table region, status = %08x\n\n", status); else printf ("Region Deleted, Start VA = %016LX, Length = %016LX\n\n", region_start_va, region_length); printf ("\n"); }

This example program displays the following output:

Shared Page Table Region Creation Attempt: Size = 67108864 Shared Page Table Region Created: VA = FFFFFFFBFC000000, Size = 67108864 Create and map to section In_Memory_Database Section In_Memory_Database created, Section Length = 67108864 Mapped VA = FFFFFFFBFC000000, Mapped Length = 67108864 Delete the mapping to the memory-resident global section and the shared page table region. Region Deleted, Start VA = FFFFFFFBFC000000, Length = 0000000004000000

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