HP OpenVMS systems documentation

If your code calls either of the following routines, you must modify your code on I64:

Alpha Routine	New Alpha and I64 Routine
status = mmg$alloc_sva_map ( proto_pte, page_count, refcnt, &ret_svapte, &ret_sva, &ret_pfn);	status = mmg$allocate_sva_and_pfns ( page_count, 0, // flags MMG$K_NO_RAD, 0, // system_region proto_pte, refcnt, &ret_sva); ret_svapte = va_pte_to_svapte (pte_va (ret_sva));
status = mmg_std$alloc_system_va_map ( proto_pte, page_count, refcnt, system_region, &ret_sva, &ret_pfn, rad, rad_flags);	status = mmg$allocate_sva_and_pfns ( page_count, rad_flags, rad, system_region, proto_pte, refcnt, &ret_sva);

Prototype

int mmg$allocate_sva_and_pfns ( unsigned __int64 page_count, unsigned int flags, int color, int system_region, int proto_pte, int refcnt, VOID_PPQ ret_sva);

Page_count: Number of pages to allocate

The following table lists the MMG flags:

MMG Flag	Meaning
MMG$M_COLOR_MUST	Return PFN must be of color (RAD) specified
MMG$M_COLOR_RANDOM	Return PFN should be a random color (RAD)

Color: RAD on systems with NUMA support enabled

System_region: 0 or 1 = 32-bit S0S1address space, 2 = 64-bit S2 address space

Proto_pte: prototype PTE with low PTE bits, such as page protection, set for mapping

Refcnt: Reference count for PFNs allocated

Ret_sva: System virtual address of memory mapped

If your code calls any of the following routines, you must modify your code to call the new routine.

Alpha Routine	New Alpha and I64 Routine
status = mmg$alloc_pfn_map_sva ( proto_pte, page_count, refcnt, svapte, &ret_sva, &ret_pfn);	sva = va_pte_to_va (svapte_to_va_pte (svapte)); status = mmg$allocate_pfn_map ( page_count, 0, // flags MMG$K_NO_RAD, // color 0, // low_pfn 0, // high_pfn sva, proto_pte, refcnt); ret_pfn = svapte->pte$v_pfn;
status = mmg$alloc_pfn_map_system_va ( proto_pte, page_count, refcnt, sva, &ret_pfn, color, flags);	status = mmg$allocate_pfn_map ( page_count, flags, color, 0, // low_pfn 0, // high_pfn sva, proto_pte, refcnt); ret_pfn = pte_va (sva)->svapte>pte$v_pfn;
status = mmg$alloc_ctg_pfn_map_sva ( proto_pte, page_count, refcnt, sva, high_pfn, &ret_pfn):	status = mmg$allocate_pfn_map ( page_count, MMG$M_CONTIG, MMG$K_NO_RAD, //color, 0, // low_pfn high_pfn, sva, proto_pte, refcnt); ret_pfn = pte_va (sva)->svapte>pte$v_pfn;

Prototype

int mmg$allocate_pfn_map ( unsigned __int64 page_count, unsigned int flags, int color, PFN_T low_pfn, PFN_T high_pfn, VOID_PQ sva, int proto_pte, int refcnt);

Page_count: Number of pages to allocate

The following table lists the MMG flags.

MMG Flag	Meaning
MMG$M_COLOR_MUST	Return PFN must be of color (RAD) specified
MMG$M_COLOR_RANDOM	Return PFN should be a random color (RAD)
MMG$M_CONTIG	Allocate contiguous pages

Color: RAD on systems with NUMA support enabled

Low_pfn: lowest PFN to allocate

High_pfn: highest PFN to allocate (0, if no range)

Sva: System virtual address to map pages (sva was already allocated by the caller)

Proto_pte: prototype PTE with low PTE bits, such as page protection, set for mapping

Refcnt: Reference count for PFNs allocated

7.8 PTE Format Changes

The PFN field in the PTE is 32-bits wide on Alpha and 40-bits wide on I64. The PFN field happens to exactly overlay other fields in the PTE such as GPTX, BAKX and the combination of PGFLPAG and PGFLX.

The following table shows the field definitions for the upper PTE fields:

Field Name	Alpha Bit Position	Alpha Field Length	I64 Bit Position
PFN 32	32	24 1	40 1
BAKX 32	32	24 1	40 1
GPTX 32	32	32	32
PGFLPAG 32	24	32	24
PGFLX 56	8	56	8

Good Example

EVAX_LDQ R0,(R3) ; Read the PTE EVAX_BIC R0,#PTE$M_BAKX,R1 ; Isolate the lower PTE bits

Sometimes existing code uses the PFN field from the PTE when it should use the GPTX field. This code needs to be changed.

Existing Code

pfn = pte_contents.pte$v_pfn; if (pte_contents.pte$v_typ0 && !pte_contents.pte$v_typ1) { pte_contents = mmg$gq_gpt_base[pfn]; // Read global PTE if (pte_contents.pte$v_valid) pfn = pte_contents.pte$v_pfn; // Read pfn from valid GPTE . . . }

New Code

pfn = pte_contents.pte$v_pfn; if (pte_contents.pte$v_typ0 && !pte_contents.pte$v_typ1) { gptx = pte_contents.pte$v_gptx; pte_contents = mmg$gq_gpt_base[gptx]; // Read global PTE if (pte_contents.pte$v_valid) pfn = pte_contents.pte$v_pfn; // Read pfn from global PTE . . . }