pmap_extract (9)
Leading comments
Copyright (c) 2003 Bruce M Simpson <bms@spc.org> All rights reserved. Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met: 1. Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer. 2. Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documenta...
NAME
pmap_extract pmap_extract_and_hold - map a virtual address to a physical pageSYNOPSIS
In sys/param.h In vm/vm.h In vm/pmap.h Ft vm_paddr_t Fn pmap_extract pmap_t pmap vm_offset_t va Ft vm_paddr_t Fn pmap_extract_and_hold pmap_t pmap vm_offset_t va vm_prot_t protDESCRIPTION
The Fn pmap_extract function maps a virtual address to a physical page. In certain situations, callers may use Fn pmap_extract_and_hold instead, to ensure that the returned page is held.The Fn pmap_extract_and_hold function maps a virtual address to a physical page, and atomically holds the returned page for use by the caller, only if the mapping permits the given page protection.
IMPLEMENTATION NOTES
Currently, the page protection requested by the caller is not verified.RETURN VALUES
The Fn pmap_extract function will return the physical page address associated with the virtual address Fa va inside the physical map Fa pmap . If the mapping does not exist, or if the Fa pmap parameter is NULL then NULL will be returned.The Fn pmap_extract_and_hold function will return the physical page address associated with the virtual address Fa va inside the physical map Fa pmap . If the mapping does not exist, the result is a no-op, and NULL will be returned.