NAME

     pmap_enter — insert a virtual page into a physical map

SYNOPSIS

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

     int
     pmap_enter(pmap_t pmap, vm_offset_t va, vm_page_t m, vm_prot_t prot, u_int flags, int8_t psind);

DESCRIPTION

     The pmap_enter() function creates a mapping in the physical map pmap from the virtual address va to the
     physical page m with the protection prot.  Any previous mapping at the virtual address va is destroyed.

     The flags argument may have the following values:

     VM_PROT_READ        A read access to the given virtual address triggered the call.

     VM_PROT_WRITE       A write access to the given virtual address triggered the call.

     VM_PROT_EXECUTE     An execute access to the given virtual address triggered the call.

     PMAP_ENTER_WIRED    The mapping should be marked as wired.

     PMAP_ENTER_NOSLEEP  This function may not sleep during creation of the mapping.  If the mapping cannot be
                         created without sleeping, an appropriate Mach VM error is returned.
     If the PMAP_ENTER_NOSLEEP flag is not specified, this function must create the requested mapping before
     returning.  It may not fail.  In order to create the requested mapping, this function may destroy any non-
     wired mapping in any pmap.

     The psind parameter specifies the page size that should be used by the mapping.  The supported page sizes
     are described by the global array pagesizes[].  The desired page size is specified by passing the index of
     the array element that equals the desired page size.

     When the pmap_enter() function destroys or updates a managed mapping, including an existing mapping at
     virtual address va, it updates the vm_page structure corresponding to the previously mapped physical page.
     If the physical page was accessed through the managed mapping, then the vm_page structure's PGA_REFERENCED
     aflag is set.  If the physical page was modified through the managed mapping, then the vm_page_dirty()
     function is called on the vm_page structure.

     The PGA_WRITEABLE aflag must be set for the page m if the new mapping is managed and writeable.  It is
     advised to clear PGA_WRITEABLE for destroyed mappings if the implementation can ensure that no other
     writeable managed mappings for the previously mapped pages exist.

     If the request modifies an existing mapping to use a different physical page, an implementation of
     pmap_enter must invalidate the previous mapping before installing the new one.  This ensures that all
     threads sharing the pmap keep a consistent view of the mapping, which is necessary for the correct handling
     of CoW (copy on write) faults.

     If the page m is managed, the page must be busied by the caller or the owning object must be locked.  In
     the later case, the PMAP_ENTER_NOSLEEP must be specified by the caller.

     The pmap_enter() function must handle the multiprocessor TLB consistency for the given address.

NOTES

     On arm and i386 architectures the existing implementation of the pmap_enter function is incomplete, only
     value 0 for psind is supported.  Other supported architectures, except amd64, have pagesizes[] array of
     size 1.

RETURN VALUES

     If successful, the pmap_enter() function returns KERN_SUCCESS.  If the PMAP_ENTER_NOSLEEP flag was
     specified and the resources required for the mapping cannot be acquired without sleeping,
     KERN_RESOURCE_SHORTAGE is returned.

SEE ALSO

     pmap(9)

AUTHORS

     This manual page was first written by Bruce M Simpson <bms@spc.org> and then rewritten by
     Alan Cox <alc@FreeBSD.org> and
     Konstantin Belousov <kib@FreeBSD.org>.