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pmap_extract(9) [debian man page]

PMAP_EXTRACT(9) 					   BSD Kernel Developer's Manual					   PMAP_EXTRACT(9)

NAME

     pmap_extract, pmap_extract_and_hold -- map a virtual address to a physical page

SYNOPSIS

     #include <sys/param.h>
     #include <vm/vm.h>
     #include <vm/pmap.h>

     vm_paddr_t
     pmap_extract(pmap_t pmap, vm_offset_t va);

     vm_paddr_t
     pmap_extract_and_hold(pmap_t pmap, vm_offset_t va, vm_prot_t prot);

DESCRIPTION

     The pmap_extract() function maps a virtual address to a physical page.  In certain situations, callers may use pmap_extract_and_hold()
     instead, to ensure that the returned page is held.

     The 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 pmap_extract() function will return the physical page address associated with the virtual address va inside the physical map pmap.  If
     the mapping does not exist, or if the pmap parameter is NULL, then NULL will be returned.

     The pmap_extract_and_hold() function will return the physical page address associated with the virtual address va inside the physical map
     pmap.  If the mapping does not exist, the result is a no-op, and NULL will be returned.

SEE ALSO

     mutex(9), pmap(9)

AUTHORS

     The pmap_extract_and_hold() function was implemented by Alan L. Cox <alc@imimic.com>.  This manual page was written by Bruce M Simpson
     <bms@spc.org>.

BSD
								   July 21, 2003							       BSD

Check Out this Related Man Page

PMAP(9) 						   BSD Kernel Developer's Manual						   PMAP(9)

NAME

     pmap -- machine-dependent portion of virtual memory subsystem

SYNOPSIS

     #include <sys/param.h>
     #include <vm/vm.h>
     #include <vm/pmap.h>

DESCRIPTION

     The pmap module is the machine-dependent portion of the FreeBSD VM (Virtual Memory) sub-system.  Each function documented herein must have
     its own architecture-dependent implementation.

     The pmap module is responsible for managing hardware-dependent objects such as page tables, address maps, TLBs, etc.

     Machine-dependent code must provide the header file <machine/pmap.h>.  This file contains the definition of the pmap structure:

	   struct pmap {
		   /* Contents defined by pmap implementation. */
	   };
	   typedef struct pmap *pmap_t;

     This header file may also define other data structures used by the pmap implementation.

     The header file <vm/pmap.h> defines a structure for tracking pmap statistics (see below).	This structure is defined as:

	   struct pmap_statistics {
		   long        resident_count; /* number of mapped pages */
		   long        wired_count;    /* number of wired pages */
	   };

     The implementation's struct pmap must contain an instance of this structure having the name pm_stats, and it must be updated by the implemen-
     tation after each relevant pmap operation.

SEE ALSO

     pmap(9), pmap_activate(9), pmap_clear_modify(9), pmap_copy(9), pmap_copy_page(9), pmap_enter(9), pmap_extract(9), pmap_extract_and_hold(9),
     pmap_growkernel(9), pmap_init(9), pmap_init2(9), pmap_is_modified(9), pmap_is_prefaultable(9), pmap_map(9), pmap_mincore(9),
     pmap_object_init_pt(9), pmap_page_exists_quick(9), pmap_page_init(9), pmap_pinit(9), pmap_pinit0(9), pmap_pinit2(9), pmap_protect(9),
     pmap_qenter(9), pmap_qremove(9), pmap_release(9), pmap_remove(9), pmap_remove_all(9), pmap_remove_pages(9), pmap_resident_count(9),
     pmap_ts_referenced(9), pmap_unwire(9), pmap_wired_count(9), pmap_zero_area(9), pmap_zero_idle(9), pmap_zero_page(9), vm_map(9)

AUTHORS

     This manual page was written by Bruce M Simpson <bms@spc.org>.

BSD
								  August 3, 2014							       BSD
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