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PMAP_EXTRACT (9) \| Kernel routines \| Unix Manual Pages \| :man▋ NAME pmap_extract, pmap_extract_and_hold - map a virtual address to a physical page CONTENTS Synopsis Description Implementation Notes Return Values See Also Authors SYNOPSIS .In sys/param.h .In vm/vm.h .In 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. In the `pmap_extract_and_hold` function, the Giant lock is held for the duration of the call to ensure that only a single caller is present. 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

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