xref: /dragonfly/sys/platform/vkernel64/platform/pmap.c (revision 5229377c)

/*
 * Copyright (c) 1991 Regents of the University of California.
 * Copyright (c) 1994 John S. Dyson
 * Copyright (c) 1994 David Greenman
 * Copyright (c) 2003 Peter Wemm
 * Copyright (c) 2005-2008 Alan L. Cox <alc@cs.rice.edu>
 * Copyright (c) 2008-2019 The DragonFly Project.
 * Copyright (c) 2008, 2009 Jordan Gordeev.
 * All rights reserved.
 *
 * This code is derived from software contributed to Berkeley by
 * the Systems Programming Group of the University of Utah Computer
 * Science Department and William Jolitz of UUNET Technologies Inc.
 *
 * 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
 *    documentation and/or other materials provided with the distribution.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *	This product includes software developed by the University of
 *	California, Berkeley and its contributors.
 * 4. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 *
 *	from:	@(#)pmap.c	7.7 (Berkeley)	5/12/91
 * $FreeBSD: src/sys/i386/i386/pmap.c,v 1.250.2.18 2002/03/06 22:48:53 silby Exp $
 */

/*
 * Manages physical address maps.
 */

#include "opt_msgbuf.h"

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/kernel.h>
#include <sys/proc.h>
#include <sys/msgbuf.h>
#include <sys/vmmeter.h>
#include <sys/mman.h>
#include <sys/vmspace.h>

#include <vm/vm.h>
#include <vm/vm_param.h>
#include <sys/sysctl.h>
#include <sys/lock.h>
#include <vm/vm_kern.h>
#include <vm/vm_page.h>
#include <vm/vm_map.h>
#include <vm/vm_object.h>
#include <vm/vm_extern.h>
#include <vm/vm_pageout.h>
#include <vm/vm_pager.h>
#include <vm/vm_zone.h>

#include <sys/thread2.h>
#include <sys/spinlock2.h>
#include <vm/vm_page2.h>

#include <machine/cputypes.h>
#include <machine/md_var.h>
#include <machine/specialreg.h>
#include <machine/smp.h>
#include <machine/globaldata.h>
#include <machine/pcb.h>
#include <machine/pmap.h>
#include <machine/pmap_inval.h>

#include <ddb/ddb.h>

#include <stdio.h>
#include <assert.h>
#include <stdlib.h>

#define PMAP_KEEP_PDIRS
#ifndef PMAP_SHPGPERPROC
#define PMAP_SHPGPERPROC 1000
#endif

#if defined(DIAGNOSTIC)
#define PMAP_DIAGNOSTIC
#endif

#define MINPV 2048

#if !defined(PMAP_DIAGNOSTIC)
#define PMAP_INLINE __inline
#else
#define PMAP_INLINE
#endif

/*
 * Get PDEs and PTEs for user/kernel address space
 */
static pd_entry_t *pmap_pde(pmap_t pmap, vm_offset_t va);
#define pdir_pde(m, v) (m[(vm_offset_t)(v) >> PDRSHIFT])

#define pmap_pde_v(pte)		((*(pd_entry_t *)pte & VPTE_V) != 0)
#define pmap_pte_w(pte)		((*(pt_entry_t *)pte & VPTE_WIRED) != 0)
#define pmap_pte_m(pte)		((*(pt_entry_t *)pte & VPTE_M) != 0)
#define pmap_pte_u(pte)		((*(pt_entry_t *)pte & VPTE_A) != 0)
#define pmap_pte_v(pte)		((*(pt_entry_t *)pte & VPTE_V) != 0)

/*
 * Given a map and a machine independent protection code,
 * convert to a vax protection code.
 */
#define pte_prot(m, p)		\
	(protection_codes[p & (VM_PROT_READ|VM_PROT_WRITE|VM_PROT_EXECUTE)])
static uint64_t protection_codes[8];

static struct pmap kernel_pmap_store;
struct pmap *kernel_pmap = &kernel_pmap_store;

static boolean_t pmap_initialized = FALSE;	/* Has pmap_init completed? */

static struct vm_object kptobj;
static int nkpt;

static uint64_t	KPDphys;	/* phys addr of kernel level 2 */
uint64_t		KPDPphys;	/* phys addr of kernel level 3 */
uint64_t		KPML4phys;	/* phys addr of kernel level 4 */

extern void *vkernel_stack;

/*
 * Data for the pv entry allocation mechanism
 */
static vm_zone_t pvzone;
static struct vm_zone pvzone_store;
static vm_pindex_t pv_entry_count = 0;
static vm_pindex_t pv_entry_max = 0;
static vm_pindex_t pv_entry_high_water = 0;
static int pmap_pagedaemon_waken = 0;
static struct pv_entry *pvinit;

/*
 * All those kernel PT submaps that BSD is so fond of
 */
pt_entry_t *CMAP1 = NULL, *ptmmap;
caddr_t CADDR1 = NULL;
static pt_entry_t *msgbufmap;

uint64_t KPTphys;

static PMAP_INLINE void	free_pv_entry (pv_entry_t pv);
static pv_entry_t get_pv_entry (void);
static void	x86_64_protection_init (void);
static __inline void	pmap_clearbit (vm_page_t m, int bit);

static void	pmap_remove_all (vm_page_t m);
static int pmap_remove_pte (struct pmap *pmap, pt_entry_t *ptq,
				pt_entry_t oldpte, vm_offset_t sva);
static void pmap_remove_page (struct pmap *pmap, vm_offset_t va);
static int pmap_remove_entry (struct pmap *pmap, vm_page_t m,
				vm_offset_t va);
static boolean_t pmap_testbit (vm_page_t m, int bit);
static void pmap_insert_entry (pmap_t pmap, vm_offset_t va,
				vm_page_t mpte, vm_page_t m, pv_entry_t);

static vm_page_t pmap_allocpte (pmap_t pmap, vm_offset_t va);

static int pmap_release_free_page (pmap_t pmap, vm_page_t p);
static vm_page_t _pmap_allocpte (pmap_t pmap, vm_pindex_t ptepindex);
static vm_page_t pmap_page_lookup (vm_object_t object, vm_pindex_t pindex);
static int pmap_unuse_pt (pmap_t, vm_offset_t, vm_page_t);

static int
pv_entry_compare(pv_entry_t pv1, pv_entry_t pv2)
{
	if (pv1->pv_va < pv2->pv_va)
		return(-1);
	if (pv1->pv_va > pv2->pv_va)
		return(1);
	return(0);
}

RB_GENERATE2(pv_entry_rb_tree, pv_entry, pv_entry,
	    pv_entry_compare, vm_offset_t, pv_va);

static __inline vm_pindex_t
pmap_pt_pindex(vm_offset_t va)
{
	return va >> PDRSHIFT;
}

static __inline vm_pindex_t
pmap_pte_index(vm_offset_t va)
{
	return ((va >> PAGE_SHIFT) & ((1ul << NPTEPGSHIFT) - 1));
}

static __inline vm_pindex_t
pmap_pde_index(vm_offset_t va)
{
	return ((va >> PDRSHIFT) & ((1ul << NPDEPGSHIFT) - 1));
}

static __inline vm_pindex_t
pmap_pdpe_index(vm_offset_t va)
{
	return ((va >> PDPSHIFT) & ((1ul << NPDPEPGSHIFT) - 1));
}

static __inline vm_pindex_t
pmap_pml4e_index(vm_offset_t va)
{
	return ((va >> PML4SHIFT) & ((1ul << NPML4EPGSHIFT) - 1));
}

/* Return a pointer to the PML4 slot that corresponds to a VA */
static __inline pml4_entry_t *
pmap_pml4e(pmap_t pmap, vm_offset_t va)
{
	return (&pmap->pm_pml4[pmap_pml4e_index(va)]);
}

/* Return a pointer to the PDP slot that corresponds to a VA */
static __inline pdp_entry_t *
pmap_pml4e_to_pdpe(pml4_entry_t *pml4e, vm_offset_t va)
{
	pdp_entry_t *pdpe;

	pdpe = (pdp_entry_t *)PHYS_TO_DMAP(*pml4e & VPTE_FRAME);
	return (&pdpe[pmap_pdpe_index(va)]);
}

/* Return a pointer to the PDP slot that corresponds to a VA */
static __inline pdp_entry_t *
pmap_pdpe(pmap_t pmap, vm_offset_t va)
{
	pml4_entry_t *pml4e;

	pml4e = pmap_pml4e(pmap, va);
	if ((*pml4e & VPTE_V) == 0)
		return NULL;
	return (pmap_pml4e_to_pdpe(pml4e, va));
}

/* Return a pointer to the PD slot that corresponds to a VA */
static __inline pd_entry_t *
pmap_pdpe_to_pde(pdp_entry_t *pdpe, vm_offset_t va)
{
	pd_entry_t *pde;

	pde = (pd_entry_t *)PHYS_TO_DMAP(*pdpe & VPTE_FRAME);
	return (&pde[pmap_pde_index(va)]);
}

/* Return a pointer to the PD slot that corresponds to a VA */
static __inline pd_entry_t *
pmap_pde(pmap_t pmap, vm_offset_t va)
{
	pdp_entry_t *pdpe;

	pdpe = pmap_pdpe(pmap, va);
	if (pdpe == NULL || (*pdpe & VPTE_V) == 0)
		 return NULL;
	return (pmap_pdpe_to_pde(pdpe, va));
}

/* Return a pointer to the PT slot that corresponds to a VA */
static __inline pt_entry_t *
pmap_pde_to_pte(pd_entry_t *pde, vm_offset_t va)
{
	pt_entry_t *pte;

	pte = (pt_entry_t *)PHYS_TO_DMAP(*pde & VPTE_FRAME);
	return (&pte[pmap_pte_index(va)]);
}

/*
 * Hold pt_m for page table scans to prevent it from getting reused out
 * from under us across blocking conditions in the body of the loop.
 */
static __inline
vm_page_t
pmap_hold_pt_page(pd_entry_t *pde, vm_offset_t va)
{
	pt_entry_t pte;
	vm_page_t pt_m;

	pte = (pt_entry_t)*pde;
	KKASSERT(pte != 0);
	pt_m = PHYS_TO_VM_PAGE(pte & VPTE_FRAME);
	vm_page_hold(pt_m);

	return pt_m;
}

/* Return a pointer to the PT slot that corresponds to a VA */
static __inline pt_entry_t *
pmap_pte(pmap_t pmap, vm_offset_t va)
{
	pd_entry_t *pde;

	pde = pmap_pde(pmap, va);
	if (pde == NULL || (*pde & VPTE_V) == 0)
		return NULL;
	if ((*pde & VPTE_PS) != 0)	/* compat with x86 pmap_pte() */
		return ((pt_entry_t *)pde);
	return (pmap_pde_to_pte(pde, va));
}

static PMAP_INLINE pt_entry_t *
vtopte(vm_offset_t va)
{
	pt_entry_t *x;
	x = pmap_pte(kernel_pmap, va);
	assert(x != NULL);
	return x;
}

static __inline pd_entry_t *
vtopde(vm_offset_t va)
{
	pd_entry_t *x;
	x = pmap_pde(kernel_pmap, va);
	assert(x != NULL);
	return x;
}

/*
 * Returns the physical address translation from va for a user address.
 * (vm_paddr_t)-1 is returned on failure.
 */
vm_paddr_t
uservtophys(vm_offset_t va)
{
	struct vmspace *vm = curproc->p_vmspace;
	vm_page_t m;
	vm_paddr_t pa;
	int error;
	int busy;

	/* XXX No idea how to handle this case in a simple way, just abort */
	if (PAGE_SIZE - (va & PAGE_MASK) < sizeof(u_int))
		return ((vm_paddr_t)-1);

	m = vm_fault_page(&vm->vm_map, trunc_page(va),
			  VM_PROT_READ|VM_PROT_WRITE,
			  VM_FAULT_NORMAL,
			  &error, &busy);
	if (error)
		return ((vm_paddr_t)-1);

	pa = VM_PAGE_TO_PHYS(m) | (va & PAGE_MASK);
	if (busy)
		vm_page_wakeup(m);
	else
		vm_page_unhold(m);

	return pa;
}

static uint64_t
allocpages(vm_paddr_t *firstaddr, int n)
{
	uint64_t ret;

	ret = *firstaddr;
	/*bzero((void *)ret, n * PAGE_SIZE); not mapped yet */
	*firstaddr += n * PAGE_SIZE;
	return (ret);
}

static void
create_pagetables(vm_paddr_t *firstaddr, int64_t ptov_offset)
{
	int i;
	pml4_entry_t *KPML4virt;
	pdp_entry_t *KPDPvirt;
	pd_entry_t *KPDvirt;
	pt_entry_t *KPTvirt;
	int kpml4i = pmap_pml4e_index(ptov_offset);
	int kpdpi = pmap_pdpe_index(ptov_offset);
	int kpdi = pmap_pde_index(ptov_offset);

	/*
         * Calculate NKPT - number of kernel page tables.  We have to
         * accomodoate prealloction of the vm_page_array, dump bitmap,
         * MSGBUF_SIZE, and other stuff.  Be generous.
         *
         * Maxmem is in pages.
         */
        nkpt = (Maxmem * (sizeof(struct vm_page) * 2) + MSGBUF_SIZE) / NBPDR;
	/*
	 * Allocate pages
	 */
	KPML4phys = allocpages(firstaddr, 1);
	KPDPphys = allocpages(firstaddr, NKPML4E);
	KPDphys = allocpages(firstaddr, NKPDPE);
	KPTphys = allocpages(firstaddr, nkpt);

	KPML4virt = (pml4_entry_t *)PHYS_TO_DMAP(KPML4phys);
	KPDPvirt = (pdp_entry_t *)PHYS_TO_DMAP(KPDPphys);
	KPDvirt = (pd_entry_t *)PHYS_TO_DMAP(KPDphys);
	KPTvirt = (pt_entry_t *)PHYS_TO_DMAP(KPTphys);

	bzero(KPML4virt, 1 * PAGE_SIZE);
	bzero(KPDPvirt, NKPML4E * PAGE_SIZE);
	bzero(KPDvirt, NKPDPE * PAGE_SIZE);
	bzero(KPTvirt, nkpt * PAGE_SIZE);

	/* Now map the page tables at their location within PTmap */
	for (i = 0; i < nkpt; i++) {
		KPDvirt[i + kpdi] = KPTphys + (i << PAGE_SHIFT);
		KPDvirt[i + kpdi] |= VPTE_RW | VPTE_V | VPTE_U;
	}

	/* And connect up the PD to the PDP */
	for (i = 0; i < NKPDPE; i++) {
		KPDPvirt[i + kpdpi] = KPDphys + (i << PAGE_SHIFT);
		KPDPvirt[i + kpdpi] |= VPTE_RW | VPTE_V | VPTE_U;
	}

	/* And recursively map PML4 to itself in order to get PTmap */
	KPML4virt[PML4PML4I] = KPML4phys;
	KPML4virt[PML4PML4I] |= VPTE_RW | VPTE_V | VPTE_U;

	/* Connect the KVA slot up to the PML4 */
	KPML4virt[kpml4i] = KPDPphys;
	KPML4virt[kpml4i] |= VPTE_RW | VPTE_V | VPTE_U;
}

/*
 * Typically used to initialize a fictitious page by vm/device_pager.c
 */
void
pmap_page_init(struct vm_page *m)
{
	vm_page_init(m);
	TAILQ_INIT(&m->md.pv_list);
}

/*
 *	Bootstrap the system enough to run with virtual memory.
 *
 *	On x86_64 this is called after mapping has already been enabled
 *	and just syncs the pmap module with what has already been done.
 *	[We can't call it easily with mapping off since the kernel is not
 *	mapped with PA == VA, hence we would have to relocate every address
 *	from the linked base (virtual) address "KERNBASE" to the actual
 *	(physical) address starting relative to 0]
 */
void
pmap_bootstrap(vm_paddr_t *firstaddr, int64_t ptov_offset)
{
	vm_offset_t va;
	pt_entry_t *pte;

	/*
	 * Create an initial set of page tables to run the kernel in.
	 */
	create_pagetables(firstaddr, ptov_offset);

	virtual_start = KvaStart;
	virtual_end = KvaEnd;

	/*
	 * Initialize protection array.
	 */
	x86_64_protection_init();

	/*
	 * The kernel's pmap is statically allocated so we don't have to use
	 * pmap_create, which is unlikely to work correctly at this part of
	 * the boot sequence (XXX and which no longer exists).
	 *
	 * The kernel_pmap's pm_pteobj is used only for locking and not
	 * for mmu pages.
	 */
	kernel_pmap->pm_pml4 = (pml4_entry_t *)PHYS_TO_DMAP(KPML4phys);
	kernel_pmap->pm_count = 1;
	/* don't allow deactivation */
	CPUMASK_ASSALLONES(kernel_pmap->pm_active);
	kernel_pmap->pm_pteobj = NULL;	/* see pmap_init */
	RB_INIT(&kernel_pmap->pm_pvroot);
	spin_init(&kernel_pmap->pm_spin, "pmapbootstrap");

	/*
	 * Reserve some special page table entries/VA space for temporary
	 * mapping of pages.
	 */
#define	SYSMAP(c, p, v, n)	\
	v = (c)va; va += ((n)*PAGE_SIZE); p = pte; pte += (n);

	va = virtual_start;
	pte = pmap_pte(kernel_pmap, va);
	/*
	 * CMAP1/CMAP2 are used for zeroing and copying pages.
	 */
	SYSMAP(caddr_t, CMAP1, CADDR1, 1)

#if 0 /* JGV */
	/*
	 * Crashdump maps.
	 */
	SYSMAP(caddr_t, pt_crashdumpmap, crashdumpmap, MAXDUMPPGS);
#endif

	/*
	 * ptvmmap is used for reading arbitrary physical pages via
	 * /dev/mem.
	 */
	SYSMAP(caddr_t, ptmmap, ptvmmap, 1)

	/*
	 * msgbufp is used to map the system message buffer.
	 * XXX msgbufmap is not used.
	 */
	SYSMAP(struct msgbuf *, msgbufmap, msgbufp,
	       atop(round_page(MSGBUF_SIZE)))

	virtual_start = va;

	*CMAP1 = 0;
	cpu_invltlb();
}

/*
 *	Initialize the pmap module.
 *	Called by vm_init, to initialize any structures that the pmap
 *	system needs to map virtual memory.
 *	pmap_init has been enhanced to support in a fairly consistant
 *	way, discontiguous physical memory.
 */
void
pmap_init(void)
{
	vm_pindex_t i;
	vm_pindex_t initial_pvs;

	/*
	 * object for kernel page table pages
	 */
	/* JG I think the number can be arbitrary */
	vm_object_init(&kptobj, 5);
	kernel_pmap->pm_pteobj = &kptobj;

	/*
	 * Allocate memory for random pmap data structures.  Includes the
	 * pv_head_table.
	 */
	for (i = 0; i < vm_page_array_size; i++) {
		vm_page_t m;

		m = &vm_page_array[i];
		TAILQ_INIT(&m->md.pv_list);
		m->md.pv_list_count = 0;
	}

	/*
	 * init the pv free list
	 */
	initial_pvs = vm_page_array_size;
	if (initial_pvs < MINPV)
		initial_pvs = MINPV;
	pvzone = &pvzone_store;
	pvinit = (struct pv_entry *)
		kmem_alloc(kernel_map,
			   initial_pvs * sizeof (struct pv_entry),
			   VM_SUBSYS_PVENTRY);
	zbootinit(pvzone, "PV ENTRY", sizeof (struct pv_entry), pvinit,
		initial_pvs);

	/*
	 * Now it is safe to enable pv_table recording.
	 */
	pmap_initialized = TRUE;
}

/*
 * Initialize the address space (zone) for the pv_entries.  Set a
 * high water mark so that the system can recover from excessive
 * numbers of pv entries.
 */
void
pmap_init2(void)
{
	vm_pindex_t shpgperproc = PMAP_SHPGPERPROC;

	TUNABLE_LONG_FETCH("vm.pmap.shpgperproc", &shpgperproc);
	pv_entry_max = shpgperproc * maxproc + vm_page_array_size;
	TUNABLE_LONG_FETCH("vm.pmap.pv_entries", &pv_entry_max);
	pv_entry_high_water = 9 * (pv_entry_max / 10);
	zinitna(pvzone, NULL, 0, pv_entry_max, ZONE_INTERRUPT);
}


/***************************************************
 * Low level helper routines.....
 ***************************************************/

/*
 * The modification bit is not tracked for any pages in this range. XXX
 * such pages in this maps should always use pmap_k*() functions and not
 * be managed anyhow.
 *
 * XXX User and kernel address spaces are independant for virtual kernels,
 * this function only applies to the kernel pmap.
 */
static void
pmap_track_modified(pmap_t pmap, vm_offset_t va)
{
	KKASSERT(pmap != kernel_pmap ||
		 va < clean_sva || va >= clean_eva);
}

/*
 * Extract the physical page address associated with the map/VA pair.
 *
 * No requirements.
 */
vm_paddr_t
pmap_extract(pmap_t pmap, vm_offset_t va, void **handlep)
{
	vm_paddr_t rtval;
	pt_entry_t *pte;
	pd_entry_t pde, *pdep;

	vm_object_hold(pmap->pm_pteobj);
	rtval = 0;
	pdep = pmap_pde(pmap, va);
	if (pdep != NULL) {
		pde = *pdep;
		if (pde) {
			if ((pde & VPTE_PS) != 0) {
				/* JGV */
				rtval = (pde & PG_PS_FRAME) | (va & PDRMASK);
			} else {
				pte = pmap_pde_to_pte(pdep, va);
				rtval = (*pte & VPTE_FRAME) | (va & PAGE_MASK);
			}
		}
	}
	if (handlep)
		*handlep = NULL;	/* XXX */
	vm_object_drop(pmap->pm_pteobj);

	return rtval;
}

void
pmap_extract_done(void *handle)
{
	pmap_t pmap;

	if (handle) {
		pmap = handle;
		vm_object_drop(pmap->pm_pteobj);
	}
}

/*
 * Similar to extract but checks protections, SMP-friendly short-cut for
 * vm_fault_page[_quick]().
 *
 * WARNING! THE RETURNED PAGE IS ONLY HELD AND NEITHER IT NOR ITS TARGET
 *	    DATA IS SUITABLE FOR WRITING.  Writing can interfere with
 *	    pageouts flushes, msync, etc.  The hold_count is not enough
 *	    to avoid races against pageouts and other flush code doesn't
 *	    care about hold_count.
 */
vm_page_t
pmap_fault_page_quick(pmap_t pmap __unused, vm_offset_t vaddr __unused,
		      vm_prot_t prot __unused, int *busyp __unused)
{
	return(NULL);
}

/*
 *	Routine:	pmap_kextract
 *	Function:
 *		Extract the physical page address associated
 *		kernel virtual address.
 */
vm_paddr_t
pmap_kextract(vm_offset_t va)
{
	pd_entry_t pde;
	vm_paddr_t pa;

	KKASSERT(va >= KvaStart && va < KvaEnd);

	/*
	 * The DMAP region is not included in [KvaStart, KvaEnd)
	 */
#if 0
	if (va >= DMAP_MIN_ADDRESS && va < DMAP_MAX_ADDRESS) {
		pa = DMAP_TO_PHYS(va);
	} else {
#endif
		pde = *vtopde(va);
		if (pde & VPTE_PS) {
			/* JGV */
			pa = (pde & PG_PS_FRAME) | (va & PDRMASK);
		} else {
			/*
			 * Beware of a concurrent promotion that changes the
			 * PDE at this point!  For example, vtopte() must not
			 * be used to access the PTE because it would use the
			 * new PDE.  It is, however, safe to use the old PDE
			 * because the page table page is preserved by the
			 * promotion.
			 */
			pa = *pmap_pde_to_pte(&pde, va);
			pa = (pa & VPTE_FRAME) | (va & PAGE_MASK);
		}
#if 0
	}
#endif
	return pa;
}

/***************************************************
 * Low level mapping routines.....
 ***************************************************/

/*
 * Enter a mapping into kernel_pmap.  Mappings created in this fashion
 * are not managed.  Mappings must be immediately accessible on all cpus.
 *
 * Call pmap_inval_pte() to invalidate the virtual pte and clean out the
 * real pmap and handle related races before storing the new vpte.  The
 * new semantics for kenter require use to do an UNCONDITIONAL invalidation,
 * because the entry may have previously been cleared without an invalidation.
 */
void
pmap_kenter(vm_offset_t va, vm_paddr_t pa)
{
	pt_entry_t *ptep;
	pt_entry_t npte;

	KKASSERT(va >= KvaStart && va < KvaEnd);
	npte = pa | VPTE_RW | VPTE_V | VPTE_U;
	ptep = vtopte(va);

#if 1
	pmap_inval_pte(ptep, kernel_pmap, va);
#else
	if (*pte & VPTE_V)
		pmap_inval_pte(ptep, kernel_pmap, va);
#endif
	atomic_swap_long(ptep, npte);
}

/*
 * Enter an unmanaged KVA mapping for the private use of the current
 * cpu only.
 *
 * It is illegal for the mapping to be accessed by other cpus without
 * proper invalidation.
 */
int
pmap_kenter_quick(vm_offset_t va, vm_paddr_t pa)
{
	pt_entry_t *ptep;
	pt_entry_t npte;
	int res;

	KKASSERT(va >= KvaStart && va < KvaEnd);

	npte = (vpte_t)pa | VPTE_RW | VPTE_V | VPTE_U;
	ptep = vtopte(va);

#if 1
	pmap_inval_pte_quick(ptep, kernel_pmap, va);
	res = 1;
#else
	/* FUTURE */
	res = (*ptep != 0);
	if (*pte & VPTE_V)
		pmap_inval_pte(pte, kernel_pmap, va);
#endif
	atomic_swap_long(ptep, npte);

	return res;
}

/*
 * Invalidation will occur later, ok to be lazy here.
 */
int
pmap_kenter_noinval(vm_offset_t va, vm_paddr_t pa)
{
	pt_entry_t *ptep;
	pt_entry_t npte;
	int res;

	KKASSERT(va >= KvaStart && va < KvaEnd);

	npte = (vpte_t)pa | VPTE_RW | VPTE_V | VPTE_U;
	ptep = vtopte(va);
#if 1
	res = 1;
#else
	/* FUTURE */
	res = (*ptep != 0);
#endif
	atomic_swap_long(ptep, npte);

	return res;
}

/*
 * Remove an unmanaged mapping created with pmap_kenter*().
 */
void
pmap_kremove(vm_offset_t va)
{
	pt_entry_t *ptep;

	KKASSERT(va >= KvaStart && va < KvaEnd);

	ptep = vtopte(va);
	atomic_swap_long(ptep, 0);
	pmap_inval_pte(ptep, kernel_pmap, va);
}

/*
 * Remove an unmanaged mapping created with pmap_kenter*() but synchronize
 * only with this cpu.
 *
 * Unfortunately because we optimize new entries by testing VPTE_V later
 * on, we actually still have to synchronize with all the cpus.  XXX maybe
 * store a junk value and test against 0 in the other places instead?
 */
void
pmap_kremove_quick(vm_offset_t va)
{
	pt_entry_t *ptep;

	KKASSERT(va >= KvaStart && va < KvaEnd);

	ptep = vtopte(va);
	atomic_swap_long(ptep, 0);
	pmap_inval_pte(ptep, kernel_pmap, va); /* NOT _quick */
}

/*
 * Invalidation will occur later, ok to be lazy here.
 */
void
pmap_kremove_noinval(vm_offset_t va)
{
	pt_entry_t *ptep;

	KKASSERT(va >= KvaStart && va < KvaEnd);

	ptep = vtopte(va);
	atomic_swap_long(ptep, 0);
}

/*
 *	Used to map a range of physical addresses into kernel
 *	virtual address space.
 *
 *	For now, VM is already on, we only need to map the
 *	specified memory.
 */
vm_offset_t
pmap_map(vm_offset_t *virtp, vm_paddr_t start, vm_paddr_t end, int prot)
{
	return PHYS_TO_DMAP(start);
}

/*
 * Map a set of unmanaged VM pages into KVM.
 */
static __inline void
_pmap_qenter(vm_offset_t beg_va, vm_page_t *m, int count, int doinval)
{
	vm_offset_t end_va;
	vm_offset_t va;

	end_va = beg_va + count * PAGE_SIZE;
	KKASSERT(beg_va >= KvaStart && end_va <= KvaEnd);

	for (va = beg_va; va < end_va; va += PAGE_SIZE) {
		pt_entry_t *ptep;

		ptep = vtopte(va);
		atomic_swap_long(ptep, VM_PAGE_TO_PHYS(*m) |
				       VPTE_RW | VPTE_V | VPTE_U);
		++m;
	}
	if (doinval)
		pmap_invalidate_range(kernel_pmap, beg_va, end_va);
	/* pmap_inval_pte(pte, kernel_pmap, va); */
}

void
pmap_qenter(vm_offset_t beg_va, vm_page_t *m, int count)
{
	_pmap_qenter(beg_va, m, count, 1);
}

void
pmap_qenter_noinval(vm_offset_t beg_va, vm_page_t *m, int count)
{
	_pmap_qenter(beg_va, m, count, 0);
}

/*
 * Undo the effects of pmap_qenter*().
 */
void
pmap_qremove(vm_offset_t beg_va, int count)
{
	vm_offset_t end_va;
	vm_offset_t va;

	end_va = beg_va + count * PAGE_SIZE;
	KKASSERT(beg_va >= KvaStart && end_va < KvaEnd);

	for (va = beg_va; va < end_va; va += PAGE_SIZE) {
		pt_entry_t *ptep;

		ptep = vtopte(va);
		atomic_swap_long(ptep, 0);
	}
	pmap_invalidate_range(kernel_pmap, beg_va, end_va);
}

/*
 * Unlike the real pmap code, we can't avoid calling the real-kernel.
 */
void
pmap_qremove_quick(vm_offset_t va, int count)
{
	pmap_qremove(va, count);
}

void
pmap_qremove_noinval(vm_offset_t va, int count)
{
	pmap_qremove(va, count);
}

/*
 * This routine works like vm_page_lookup() but also blocks as long as the
 * page is busy.  This routine does not busy the page it returns.
 *
 * Unless the caller is managing objects whos pages are in a known state,
 * the call should be made with a critical section held so the page's object
 * association remains valid on return.
 */
static vm_page_t
pmap_page_lookup(vm_object_t object, vm_pindex_t pindex)
{
	vm_page_t m;

	ASSERT_LWKT_TOKEN_HELD(vm_object_token(object));
	m = vm_page_lookup_busy_wait(object, pindex, TRUE, "pplookp");

	return(m);
}

/*
 * Create a new thread and optionally associate it with a (new) process.
 * NOTE! the new thread's cpu may not equal the current cpu.
 */
void
pmap_init_thread(thread_t td)
{
	/* enforce pcb placement */
	td->td_pcb = (struct pcb *)(td->td_kstack + td->td_kstack_size) - 1;
	td->td_savefpu = &td->td_pcb->pcb_save;
	td->td_sp = (char *)td->td_pcb - 16; /* JG is -16 needed on x86_64? */
}

/*
 * This routine directly affects the fork perf for a process.
 */
void
pmap_init_proc(struct proc *p)
{
}

/*
 * Unwire a page table which has been removed from the pmap.  We own the
 * wire_count, so the page cannot go away.  The page representing the page
 * table is passed in unbusied and must be busied if we cannot trivially
 * unwire it.
 *
 * XXX NOTE!  This code is not usually run because we do not currently
 *	      implement dynamic page table page removal.  The page in
 *	      its parent assumes at least 1 wire count, so no call to this
 *	      function ever sees a wire count less than 2.
 */
static int
pmap_unwire_pgtable(pmap_t pmap, vm_offset_t va, vm_page_t m)
{
	/*
	 * Try to unwire optimally.  If non-zero is returned the wire_count
	 * is 1 and we must busy the page to unwire it.
	 */
	if (vm_page_unwire_quick(m) == 0)
		return 0;

	vm_page_busy_wait(m, TRUE, "pmuwpt");
	KASSERT(m->queue == PQ_NONE,
		("_pmap_unwire_pgtable: %p->queue != PQ_NONE", m));

	if (m->wire_count == 1) {
		/*
		 * Unmap the page table page.
		 */
		/* pmap_inval_add(info, pmap, -1); */

		if (m->pindex >= (NUPT_TOTAL + NUPD_TOTAL)) {
			/* PDP page */
			pml4_entry_t *pml4;
			pml4 = pmap_pml4e(pmap, va);
			*pml4 = 0;
		} else if (m->pindex >= NUPT_TOTAL) {
			/* PD page */
			pdp_entry_t *pdp;
			pdp = pmap_pdpe(pmap, va);
			*pdp = 0;
		} else {
			/* PT page */
			pd_entry_t *pd;
			pd = pmap_pde(pmap, va);
			*pd = 0;
		}

		KKASSERT(pmap->pm_stats.resident_count > 0);
		atomic_add_long(&pmap->pm_stats.resident_count, -1);

		if (pmap->pm_ptphint == m)
			pmap->pm_ptphint = NULL;

		if (m->pindex < NUPT_TOTAL) {
			/* We just released a PT, unhold the matching PD */
			vm_page_t pdpg;

			pdpg = PHYS_TO_VM_PAGE(*pmap_pdpe(pmap, va) &
					       VPTE_FRAME);
			pmap_unwire_pgtable(pmap, va, pdpg);
		}
		if (m->pindex >= NUPT_TOTAL &&
		    m->pindex < (NUPT_TOTAL + NUPD_TOTAL)) {
			/* We just released a PD, unhold the matching PDP */
			vm_page_t pdppg;

			pdppg = PHYS_TO_VM_PAGE(*pmap_pml4e(pmap, va) &
						VPTE_FRAME);
			pmap_unwire_pgtable(pmap, va, pdppg);
		}

		/*
		 * This was our last wire, the page had better be unwired
		 * after we decrement wire_count.
		 *
		 * FUTURE NOTE: shared page directory page could result in
		 * multiple wire counts.
		 */
		vm_page_unwire(m, 0);
		KKASSERT(m->wire_count == 0);
		vm_page_flag_clear(m, PG_MAPPED | PG_WRITEABLE);
		vm_page_flash(m);
		vm_page_free(m);
		return 1;
	} else {
		/* XXX SMP race to 1 if not holding vmobj */
		vm_page_unwire(m, 0);
		vm_page_wakeup(m);
		return 0;
	}
}

/*
 * After removing a page table entry, this routine is used to
 * conditionally free the page, and manage the hold/wire counts.
 *
 * If not NULL the caller owns a wire_count on mpte, so it can't disappear.
 * If NULL the caller owns a wire_count on what would be the mpte, we must
 * look it up.
 */
static int
pmap_unuse_pt(pmap_t pmap, vm_offset_t va, vm_page_t mpte)
{
	vm_pindex_t ptepindex;

	ASSERT_LWKT_TOKEN_HELD(vm_object_token(pmap->pm_pteobj));

	if (mpte == NULL) {
		/*
		 * page table pages in the kernel_pmap are not managed.
		 */
		if (pmap == kernel_pmap)
			return(0);
		ptepindex = pmap_pt_pindex(va);
		if (pmap->pm_ptphint &&
		    (pmap->pm_ptphint->pindex == ptepindex)) {
			mpte = pmap->pm_ptphint;
		} else {
			mpte = pmap_page_lookup(pmap->pm_pteobj, ptepindex);
			pmap->pm_ptphint = mpte;
			vm_page_wakeup(mpte);
		}
	}
	return pmap_unwire_pgtable(pmap, va, mpte);
}

/*
 * Initialize pmap0/vmspace0 .  Since process 0 never enters user mode we
 * just dummy it up so it works well enough for fork().
 *
 * In DragonFly, process pmaps may only be used to manipulate user address
 * space, never kernel address space.
 */
void
pmap_pinit0(struct pmap *pmap)
{
	pmap_pinit(pmap);
}

/*
 * Initialize a preallocated and zeroed pmap structure,
 * such as one in a vmspace structure.
 */
void
pmap_pinit(struct pmap *pmap)
{
	vm_page_t ptdpg;

	/*
	 * No need to allocate page table space yet but we do need a valid
	 * page directory table.
	 */
	if (pmap->pm_pml4 == NULL) {
		pmap->pm_pml4 = (pml4_entry_t *)
			kmem_alloc_pageable(kernel_map, PAGE_SIZE,
					    VM_SUBSYS_PML4);
	}

	/*
	 * Allocate an object for the ptes
	 */
	if (pmap->pm_pteobj == NULL)
		pmap->pm_pteobj = vm_object_allocate(OBJT_DEFAULT, NUPT_TOTAL + NUPD_TOTAL + NUPDP_TOTAL + 1);

	/*
	 * Allocate the page directory page, unless we already have
	 * one cached.  If we used the cached page the wire_count will
	 * already be set appropriately.
	 */
	if ((ptdpg = pmap->pm_pdirm) == NULL) {
		ptdpg = vm_page_grab(pmap->pm_pteobj,
				     NUPT_TOTAL + NUPD_TOTAL + NUPDP_TOTAL,
				     VM_ALLOC_NORMAL | VM_ALLOC_RETRY |
				     VM_ALLOC_ZERO);
		pmap->pm_pdirm = ptdpg;
		vm_page_flag_clear(ptdpg, PG_MAPPED | PG_WRITEABLE);
		vm_page_wire(ptdpg);
		vm_page_wakeup(ptdpg);
		pmap_kenter((vm_offset_t)pmap->pm_pml4, VM_PAGE_TO_PHYS(ptdpg));
	}
	pmap->pm_count = 1;
	CPUMASK_ASSZERO(pmap->pm_active);
	pmap->pm_ptphint = NULL;
	RB_INIT(&pmap->pm_pvroot);
	spin_init(&pmap->pm_spin, "pmapinit");
	bzero(&pmap->pm_stats, sizeof pmap->pm_stats);
	pmap->pm_stats.resident_count = 1;
	pmap->pm_stats.wired_count = 1;
}

/*
 * Clean up a pmap structure so it can be physically freed.  This routine
 * is called by the vmspace dtor function.  A great deal of pmap data is
 * left passively mapped to improve vmspace management so we have a bit
 * of cleanup work to do here.
 *
 * No requirements.
 */
void
pmap_puninit(pmap_t pmap)
{
	vm_page_t p;

	KKASSERT(CPUMASK_TESTZERO(pmap->pm_active));
	if ((p = pmap->pm_pdirm) != NULL) {
		KKASSERT(pmap->pm_pml4 != NULL);
		pmap_kremove((vm_offset_t)pmap->pm_pml4);
		vm_page_busy_wait(p, TRUE, "pgpun");
		vm_page_unwire(p, 0);
		vm_page_flag_clear(p, PG_MAPPED | PG_WRITEABLE);
		vm_page_free(p);
		pmap->pm_pdirm = NULL;
		atomic_add_long(&pmap->pm_stats.wired_count, -1);
		KKASSERT(pmap->pm_stats.wired_count == 0);
	}
	if (pmap->pm_pml4) {
		kmem_free(kernel_map, (vm_offset_t)pmap->pm_pml4, PAGE_SIZE);
		pmap->pm_pml4 = NULL;
	}
	if (pmap->pm_pteobj) {
		vm_object_deallocate(pmap->pm_pteobj);
		pmap->pm_pteobj = NULL;
	}
}

/*
 * This function is now unused (used to add the pmap to the pmap_list)
 */
void
pmap_pinit2(struct pmap *pmap)
{
}

/*
 * Attempt to release and free a vm_page in a pmap.  Returns 1 on success,
 * 0 on failure (if the procedure had to sleep).
 *
 * When asked to remove the page directory page itself, we actually just
 * leave it cached so we do not have to incur the SMP inval overhead of
 * removing the kernel mapping.  pmap_puninit() will take care of it.
 */
static int
pmap_release_free_page(struct pmap *pmap, vm_page_t p)
{
	/*
	 * This code optimizes the case of freeing non-busy
	 * page-table pages.  Those pages are zero now, and
	 * might as well be placed directly into the zero queue.
	 */
	if (vm_page_busy_try(p, TRUE)) {
		vm_page_sleep_busy(p, TRUE, "pmaprl");
		return 1;
	}

	/*
	 * Remove the page table page from the processes address space.
	 */
	if (p->pindex == NUPT_TOTAL + NUPD_TOTAL + NUPDP_TOTAL) {
		/*
		 * We are the pml4 table itself.
		 */
		/* XXX anything to do here? */
	} else if (p->pindex >= (NUPT_TOTAL + NUPD_TOTAL)) {
		/*
		 * We are a PDP page.
		 * We look for the PML4 entry that points to us.
		 */
		vm_page_t m4;
		pml4_entry_t *pml4;
		int idx;

		m4 = vm_page_lookup(pmap->pm_pteobj,
				    NUPT_TOTAL + NUPD_TOTAL + NUPDP_TOTAL);
		KKASSERT(m4 != NULL);
		pml4 = (pml4_entry_t *)PHYS_TO_DMAP(VM_PAGE_TO_PHYS(m4));
		idx = (p->pindex - (NUPT_TOTAL + NUPD_TOTAL)) % NPML4EPG;
		KKASSERT(pml4[idx] != 0);
		if (pml4[idx] == 0)
			kprintf("pmap_release: Unmapped PML4\n");
		pml4[idx] = 0;
		vm_page_unwire_quick(m4);
	} else if (p->pindex >= NUPT_TOTAL) {
		/*
		 * We are a PD page.
		 * We look for the PDP entry that points to us.
		 */
		vm_page_t m3;
		pdp_entry_t *pdp;
		int idx;

		m3 = vm_page_lookup(pmap->pm_pteobj,
				    NUPT_TOTAL + NUPD_TOTAL +
				     (p->pindex - NUPT_TOTAL) / NPDPEPG);
		KKASSERT(m3 != NULL);
		pdp = (pdp_entry_t *)PHYS_TO_DMAP(VM_PAGE_TO_PHYS(m3));
		idx = (p->pindex - NUPT_TOTAL) % NPDPEPG;
		KKASSERT(pdp[idx] != 0);
		if (pdp[idx] == 0)
			kprintf("pmap_release: Unmapped PDP %d\n", idx);
		pdp[idx] = 0;
		vm_page_unwire_quick(m3);
	} else {
		/* We are a PT page.
		 * We look for the PD entry that points to us.
		 */
		vm_page_t m2;
		pd_entry_t *pd;
		int idx;

		m2 = vm_page_lookup(pmap->pm_pteobj,
				    NUPT_TOTAL + p->pindex / NPDEPG);
		KKASSERT(m2 != NULL);
		pd = (pd_entry_t *)PHYS_TO_DMAP(VM_PAGE_TO_PHYS(m2));
		idx = p->pindex % NPDEPG;
		if (pd[idx] == 0)
			kprintf("pmap_release: Unmapped PD %d\n", idx);
		pd[idx] = 0;
		vm_page_unwire_quick(m2);
	}
	KKASSERT(pmap->pm_stats.resident_count > 0);
	atomic_add_long(&pmap->pm_stats.resident_count, -1);

	if (p->wire_count > 1)  {
		panic("pmap_release: freeing held pt page "
		      "pmap=%p pg=%p dmap=%p pi=%ld {%ld,%ld,%ld}",
		      pmap, p, (void *)PHYS_TO_DMAP(VM_PAGE_TO_PHYS(p)),
		      p->pindex, NUPT_TOTAL, NUPD_TOTAL, NUPDP_TOTAL);
	}

	if (pmap->pm_ptphint == p)
		pmap->pm_ptphint = NULL;

	/*
	 * We leave the top-level page table page cached, wired, and mapped in
	 * the pmap until the dtor function (pmap_puninit()) gets called.
	 * However, still clean it up.
	 */
	if (p->pindex == NUPT_TOTAL + NUPD_TOTAL + NUPDP_TOTAL) {
		bzero(pmap->pm_pml4, PAGE_SIZE);
		vm_page_wakeup(p);
	} else {
		vm_page_unwire(p, 0);
		vm_page_flag_clear(p, PG_MAPPED | PG_WRITEABLE);
		vm_page_free(p);
		atomic_add_long(&pmap->pm_stats.wired_count, -1);
	}
	return 0;
}

/*
 * Locate the requested PT, PD, or PDP page table page.
 *
 * Returns a busied page, caller must vm_page_wakeup() when done.
 */
static vm_page_t
_pmap_allocpte(pmap_t pmap, vm_pindex_t ptepindex)
{
	vm_page_t m;
	vm_page_t pm;
	vm_pindex_t pindex;
	pt_entry_t *ptep;
	pt_entry_t data;

	/*
	 * Find or fabricate a new pagetable page.  A non-zero wire_count
	 * indicates that the page has already been mapped into its parent.
	 */
	m = vm_page_grab(pmap->pm_pteobj, ptepindex,
			 VM_ALLOC_NORMAL | VM_ALLOC_ZERO | VM_ALLOC_RETRY);
	if (m->wire_count != 0)
		return m;

	/*
	 * Map the page table page into its parent, giving it 1 wire count.
	 */
	vm_page_wire(m);
	vm_page_unqueue(m);
	atomic_add_long(&pmap->pm_stats.resident_count, 1);
	vm_page_flag_set(m, PG_MAPPED | PG_WRITEABLE);

	data = VM_PAGE_TO_PHYS(m) |
	       VPTE_RW | VPTE_V | VPTE_U | VPTE_A | VPTE_M | VPTE_WIRED;
	atomic_add_long(&pmap->pm_stats.wired_count, 1);

	if (ptepindex >= (NUPT_TOTAL + NUPD_TOTAL)) {
		/*
		 * Map PDP into the PML4
		 */
		pindex = ptepindex - (NUPT_TOTAL + NUPD_TOTAL);
		pindex &= (NUPDP_TOTAL - 1);
		ptep = (pt_entry_t *)pmap->pm_pml4;
		pm = NULL;
	} else if (ptepindex >= NUPT_TOTAL) {
		/*
		 * Map PD into its PDP
		 */
		pindex = (ptepindex - NUPT_TOTAL) >> NPDPEPGSHIFT;
		pindex += NUPT_TOTAL + NUPD_TOTAL;
		pm = _pmap_allocpte(pmap, pindex);
		pindex = (ptepindex - NUPT_TOTAL) & (NPDPEPG - 1);
		ptep = (void *)PHYS_TO_DMAP(pm->phys_addr);
	} else {
		/*
		 * Map PT into its PD
		 */
		pindex = ptepindex >> NPDPEPGSHIFT;
		pindex += NUPT_TOTAL;
		pm = _pmap_allocpte(pmap, pindex);
		pindex = ptepindex & (NPTEPG - 1);
		ptep = (void *)PHYS_TO_DMAP(pm->phys_addr);
	}

	/*
	 * Install the pte in (pm).  (m) prevents races.
	 */
	ptep += pindex;
	data = atomic_swap_long(ptep, data);
	if (pm) {
		vm_page_wire_quick(pm);
		vm_page_wakeup(pm);
	}
	pmap->pm_ptphint = pm;

	return m;
}

/*
 * Determine the page table page required to access the VA in the pmap
 * and allocate it if necessary.  Return a held vm_page_t for the page.
 *
 * Only used with user pmaps.
 */
static vm_page_t
pmap_allocpte(pmap_t pmap, vm_offset_t va)
{
	vm_pindex_t ptepindex;
	vm_page_t m;

	ASSERT_LWKT_TOKEN_HELD(vm_object_token(pmap->pm_pteobj));

	/*
	 * Calculate pagetable page index, and return the PT page to
	 * the caller.
	 */
	ptepindex = pmap_pt_pindex(va);
	m = _pmap_allocpte(pmap, ptepindex);

	return m;
}

/***************************************************
 * Pmap allocation/deallocation routines.
 ***************************************************/

/*
 * Release any resources held by the given physical map.
 * Called when a pmap initialized by pmap_pinit is being released.
 * Should only be called if the map contains no valid mappings.
 */
static int pmap_release_callback(struct vm_page *p, void *data);

void
pmap_release(struct pmap *pmap)
{
	vm_object_t object = pmap->pm_pteobj;
	struct rb_vm_page_scan_info info;

	KKASSERT(pmap != kernel_pmap);

#if defined(DIAGNOSTIC)
	if (object->ref_count != 1)
		panic("pmap_release: pteobj reference count != 1");
#endif

	info.pmap = pmap;
	info.object = object;

	KASSERT(CPUMASK_TESTZERO(pmap->pm_active),
		("pmap %p still active! %016jx",
		pmap,
		(uintmax_t)CPUMASK_LOWMASK(pmap->pm_active)));

	vm_object_hold(object);
	do {
		info.error = 0;
		info.mpte = NULL;
		info.limit = object->generation;

		vm_page_rb_tree_RB_SCAN(&object->rb_memq, NULL,
				        pmap_release_callback, &info);
		if (info.error == 0 && info.mpte) {
			if (pmap_release_free_page(pmap, info.mpte))
				info.error = 1;
		}
	} while (info.error);

	pmap->pm_ptphint = NULL;

	KASSERT((pmap->pm_stats.wired_count == (pmap->pm_pdirm != NULL)),
		("pmap_release: dangling count %p %ld",
		pmap, pmap->pm_stats.wired_count));

	vm_object_drop(object);
}

static int
pmap_release_callback(struct vm_page *p, void *data)
{
	struct rb_vm_page_scan_info *info = data;

	if (p->pindex == NUPT_TOTAL + NUPD_TOTAL + NUPDP_TOTAL) {
		info->mpte = p;
		return(0);
	}
	if (pmap_release_free_page(info->pmap, p)) {
		info->error = 1;
		return(-1);
	}
	if (info->object->generation != info->limit) {
		info->error = 1;
		return(-1);
	}
	return(0);
}

/*
 * Grow the number of kernel page table entries, if needed.
 *
 * kernel_map must be locked exclusively by the caller.
 */
void
pmap_growkernel(vm_offset_t kstart, vm_offset_t kend)
{
	vm_offset_t addr;
	vm_paddr_t paddr;
	vm_offset_t ptppaddr;
	vm_page_t nkpg;
	pd_entry_t *pde, newpdir;
	pdp_entry_t newpdp;

	addr = kend;

	vm_object_hold(&kptobj);
	if (kernel_vm_end == 0) {
		kernel_vm_end = KvaStart;
		nkpt = 0;
		while ((*pmap_pde(kernel_pmap, kernel_vm_end) & VPTE_V) != 0) {
			kernel_vm_end =
			    rounddown2(kernel_vm_end + PAGE_SIZE * NPTEPG,
				PAGE_SIZE * NPTEPG);
			nkpt++;
			if (kernel_vm_end - 1 >= vm_map_max(kernel_map)) {
				kernel_vm_end = vm_map_max(kernel_map);
				break;
			}
		}
	}
	addr = roundup2(addr, PAGE_SIZE * NPTEPG);
	if (addr - 1 >= vm_map_max(kernel_map))
		addr = vm_map_max(kernel_map);
	while (kernel_vm_end < addr) {
		pde = pmap_pde(kernel_pmap, kernel_vm_end);
		if (pde == NULL) {
			/* We need a new PDP entry */
			nkpg = vm_page_alloc(&kptobj, nkpt,
			                     VM_ALLOC_NORMAL |
					     VM_ALLOC_SYSTEM |
					     VM_ALLOC_INTERRUPT);
			if (nkpg == NULL) {
				panic("pmap_growkernel: no memory to "
				      "grow kernel");
			}
			paddr = VM_PAGE_TO_PHYS(nkpg);
			pmap_zero_page(paddr);
			newpdp = (pdp_entry_t)(paddr |
					       VPTE_V | VPTE_RW | VPTE_U |
					       VPTE_A | VPTE_M | VPTE_WIRED);
			*pmap_pdpe(kernel_pmap, kernel_vm_end) = newpdp;
			atomic_add_long(&kernel_pmap->pm_stats.wired_count, 1);
			nkpt++;
			continue; /* try again */
		}
		if ((*pde & VPTE_V) != 0) {
			kernel_vm_end =
			    rounddown2(kernel_vm_end + PAGE_SIZE * NPTEPG,
				PAGE_SIZE * NPTEPG);
			if (kernel_vm_end - 1 >= vm_map_max(kernel_map)) {
				kernel_vm_end = vm_map_max(kernel_map);
				break;
			}
			continue;
		}

		/*
		 * This index is bogus, but out of the way
		 */
		nkpg = vm_page_alloc(&kptobj, nkpt,
				     VM_ALLOC_NORMAL |
				     VM_ALLOC_SYSTEM |
				     VM_ALLOC_INTERRUPT);
		if (nkpg == NULL)
			panic("pmap_growkernel: no memory to grow kernel");

		vm_page_wire(nkpg);
		ptppaddr = VM_PAGE_TO_PHYS(nkpg);
		pmap_zero_page(ptppaddr);
		newpdir = (pd_entry_t)(ptppaddr |
				       VPTE_V | VPTE_RW | VPTE_U |
				       VPTE_A | VPTE_M | VPTE_WIRED);
		*pmap_pde(kernel_pmap, kernel_vm_end) = newpdir;
		atomic_add_long(&kernel_pmap->pm_stats.wired_count, 1);
		nkpt++;

		kernel_vm_end =
		    rounddown2(kernel_vm_end + PAGE_SIZE * NPTEPG,
			PAGE_SIZE * NPTEPG);
		if (kernel_vm_end - 1 >= vm_map_max(kernel_map)) {
			kernel_vm_end = vm_map_max(kernel_map);
			break;
		}
	}
	vm_object_drop(&kptobj);
}

/*
 * Add a reference to the specified pmap.
 *
 * No requirements.
 */
void
pmap_reference(pmap_t pmap)
{
	if (pmap)
		atomic_add_int(&pmap->pm_count, 1);
}

/************************************************************************
 *	   		VMSPACE MANAGEMENT				*
 ************************************************************************
 *
 * The VMSPACE management we do in our virtual kernel must be reflected
 * in the real kernel.  This is accomplished by making vmspace system
 * calls to the real kernel.
 */
void
cpu_vmspace_alloc(struct vmspace *vm)
{
	int r;
	void *rp;
	vpte_t vpte;

#define USER_SIZE	(VM_MAX_USER_ADDRESS - VM_MIN_USER_ADDRESS)

	if (vmspace_create(&vm->vm_pmap, 0, NULL) < 0)
		panic("vmspace_create() failed");

	rp = vmspace_mmap(&vm->vm_pmap, VM_MIN_USER_ADDRESS, USER_SIZE,
			  PROT_READ|PROT_WRITE|PROT_EXEC,
			  MAP_FILE|MAP_SHARED|MAP_VPAGETABLE|MAP_FIXED,
			  MemImageFd, 0);
	if (rp == MAP_FAILED)
		panic("vmspace_mmap: failed");
	vmspace_mcontrol(&vm->vm_pmap, VM_MIN_USER_ADDRESS, USER_SIZE,
			 MADV_NOSYNC, 0);
	vpte = VM_PAGE_TO_PHYS(vmspace_pmap(vm)->pm_pdirm) |
			       VPTE_RW | VPTE_V | VPTE_U;
	r = vmspace_mcontrol(&vm->vm_pmap, VM_MIN_USER_ADDRESS, USER_SIZE,
			     MADV_SETMAP, vpte);
	if (r < 0)
		panic("vmspace_mcontrol: failed");
}

void
cpu_vmspace_free(struct vmspace *vm)
{
	if (vmspace_destroy(&vm->vm_pmap) < 0)
		panic("vmspace_destroy() failed");
}

/***************************************************
* page management routines.
 ***************************************************/

/*
 * free the pv_entry back to the free list.  This function may be
 * called from an interrupt.
 */
static __inline void
free_pv_entry(pv_entry_t pv)
{
	atomic_add_long(&pv_entry_count, -1);
	zfree(pvzone, pv);
}

/*
 * get a new pv_entry, allocating a block from the system
 * when needed.  This function may be called from an interrupt.
 */
static pv_entry_t
get_pv_entry(void)
{
	atomic_add_long(&pv_entry_count, 1);
	if (pv_entry_high_water &&
	    (pv_entry_count > pv_entry_high_water) &&
	    atomic_swap_int(&pmap_pagedaemon_waken, 1) == 0) {
		wakeup(&vm_pages_needed);
	}
	return zalloc(pvzone);
}

/*
 * This routine is very drastic, but can save the system
 * in a pinch.
 *
 * No requirements.
 */
void
pmap_collect(void)
{
	int i;
	vm_page_t m;
	static int warningdone=0;

	if (pmap_pagedaemon_waken == 0)
		return;
	pmap_pagedaemon_waken = 0;

	if (warningdone < 5) {
		kprintf("pmap_collect: collecting pv entries -- "
			"suggest increasing PMAP_SHPGPERPROC\n");
		warningdone++;
	}

	for (i = 0; i < vm_page_array_size; i++) {
		m = &vm_page_array[i];
		if (m->wire_count || m->hold_count)
			continue;
		if (vm_page_busy_try(m, TRUE) == 0) {
			if (m->wire_count == 0 && m->hold_count == 0) {
				pmap_remove_all(m);
			}
			vm_page_wakeup(m);
		}
	}
}


/*
 * If it is the first entry on the list, it is actually
 * in the header and we must copy the following entry up
 * to the header.  Otherwise we must search the list for
 * the entry.  In either case we free the now unused entry.
 *
 * pmap->pm_pteobj must be held and (m) must be spin-locked by the caller.
 */
static int
pmap_remove_entry(struct pmap *pmap, vm_page_t m, vm_offset_t va)
{
	pv_entry_t pv;
	int rtval;

	vm_page_spin_lock(m);
	pv = pv_entry_rb_tree_RB_LOOKUP(&pmap->pm_pvroot, va);

	/*
	 * Note that pv_ptem is NULL if the page table page itself is not
	 * managed, even if the page being removed IS managed.
	 */
	rtval = 0;
	if (pv) {
		TAILQ_REMOVE(&m->md.pv_list, pv, pv_list);
		if (TAILQ_EMPTY(&m->md.pv_list))
			vm_page_flag_clear(m, PG_MAPPED | PG_WRITEABLE);
		m->md.pv_list_count--;
		KKASSERT(m->md.pv_list_count >= 0);
		pv_entry_rb_tree_RB_REMOVE(&pmap->pm_pvroot, pv);
		atomic_add_int(&pmap->pm_generation, 1);
		vm_page_spin_unlock(m);
		rtval = pmap_unuse_pt(pmap, va, pv->pv_ptem);
		free_pv_entry(pv);
	} else {
		vm_page_spin_unlock(m);
		kprintf("pmap_remove_entry: could not find "
			"pmap=%p m=%p va=%016jx\n",
			pmap, m, va);
	}
	return rtval;
}

/*
 * Create a pv entry for page at pa for (pmap, va).  If the page table page
 * holding the VA is managed, mpte will be non-NULL.
 *
 * pmap->pm_pteobj must be held and (m) must be spin-locked by the caller.
 */
static void
pmap_insert_entry(pmap_t pmap, vm_offset_t va, vm_page_t mpte, vm_page_t m,
		  pv_entry_t pv)
{
	pv->pv_va = va;
	pv->pv_pmap = pmap;
	pv->pv_ptem = mpte;

	m->md.pv_list_count++;
	TAILQ_INSERT_TAIL(&m->md.pv_list, pv, pv_list);
	pv = pv_entry_rb_tree_RB_INSERT(&pmap->pm_pvroot, pv);
	vm_page_flag_set(m, PG_MAPPED);
	KKASSERT(pv == NULL);
}

/*
 * pmap_remove_pte: do the things to unmap a page in a process
 *
 * Caller holds pmap->pm_pteobj and holds the associated page table
 * page busy to prevent races.
 */
static int
pmap_remove_pte(struct pmap *pmap, pt_entry_t *ptq, pt_entry_t oldpte,
		vm_offset_t va)
{
	vm_page_t m;
	int error;

	if (ptq)
		oldpte = pmap_inval_loadandclear(ptq, pmap, va);

	if (oldpte & VPTE_WIRED)
		atomic_add_long(&pmap->pm_stats.wired_count, -1);
	KKASSERT(pmap->pm_stats.wired_count >= 0);

#if 0
	/*
	 * Machines that don't support invlpg, also don't support
	 * PG_G.  XXX PG_G is disabled for SMP so don't worry about
	 * the SMP case.
	 */
	if (oldpte & PG_G)
		cpu_invlpg((void *)va);
#endif
	KKASSERT(pmap->pm_stats.resident_count > 0);
	atomic_add_long(&pmap->pm_stats.resident_count, -1);
	if (oldpte & VPTE_MANAGED) {
		m = PHYS_TO_VM_PAGE(oldpte);

		/*
		 * NOTE: pmap_remove_entry() will spin-lock the page
		 */
		if (oldpte & VPTE_M) {
#if defined(PMAP_DIAGNOSTIC)
			if (pmap_nw_modified(oldpte)) {
				kprintf("pmap_remove: modified page not "
					"writable: va: 0x%lx, pte: 0x%lx\n",
					va, oldpte);
			}
#endif
			pmap_track_modified(pmap, va);
			vm_page_dirty(m);
		}
		if (oldpte & VPTE_A)
			vm_page_flag_set(m, PG_REFERENCED);
		error = pmap_remove_entry(pmap, m, va);
	} else {
		error = pmap_unuse_pt(pmap, va, NULL);
	}
	return error;
}

/*
 * pmap_remove_page:
 *
 * Remove a single page from a process address space.
 *
 * This function may not be called from an interrupt if the pmap is
 * not kernel_pmap.
 *
 * Caller holds pmap->pm_pteobj
 */
static void
pmap_remove_page(struct pmap *pmap, vm_offset_t va)
{
	pt_entry_t *pte;

	pte = pmap_pte(pmap, va);
	if (pte == NULL)
		return;
	if ((*pte & VPTE_V) == 0)
		return;
	pmap_remove_pte(pmap, pte, 0, va);
}

/*
 * Remove the given range of addresses from the specified map.
 *
 * It is assumed that the start and end are properly rounded to
 * the page size.
 *
 * This function may not be called from an interrupt if the pmap is
 * not kernel_pmap.
 *
 * No requirements.
 */
void
pmap_remove(struct pmap *pmap, vm_offset_t sva, vm_offset_t eva)
{
	vm_offset_t va_next;
	pml4_entry_t *pml4e;
	pdp_entry_t *pdpe;
	pd_entry_t ptpaddr, *pde;
	pt_entry_t *pte;
	vm_page_t pt_m;

	if (pmap == NULL)
		return;

	vm_object_hold(pmap->pm_pteobj);
	KKASSERT(pmap->pm_stats.resident_count >= 0);
	if (pmap->pm_stats.resident_count == 0) {
		vm_object_drop(pmap->pm_pteobj);
		return;
	}

	/*
	 * special handling of removing one page.  a very
	 * common operation and easy to short circuit some
	 * code.
	 */
	if (sva + PAGE_SIZE == eva) {
		pde = pmap_pde(pmap, sva);
		if (pde && (*pde & VPTE_PS) == 0) {
			pmap_remove_page(pmap, sva);
			vm_object_drop(pmap->pm_pteobj);
			return;
		}
	}

	for (; sva < eva; sva = va_next) {
		pml4e = pmap_pml4e(pmap, sva);
		if ((*pml4e & VPTE_V) == 0) {
			va_next = (sva + NBPML4) & ~PML4MASK;
			if (va_next < sva)
				va_next = eva;
			continue;
		}

		pdpe = pmap_pml4e_to_pdpe(pml4e, sva);
		if ((*pdpe & VPTE_V) == 0) {
			va_next = (sva + NBPDP) & ~PDPMASK;
			if (va_next < sva)
				va_next = eva;
			continue;
		}

		/*
		 * Calculate index for next page table.
		 */
		va_next = (sva + NBPDR) & ~PDRMASK;
		if (va_next < sva)
			va_next = eva;

		pde = pmap_pdpe_to_pde(pdpe, sva);
		ptpaddr = *pde;

		/*
		 * Weed out invalid mappings.
		 */
		if (ptpaddr == 0)
			continue;

		/*
		 * Check for large page.
		 */
		if ((ptpaddr & VPTE_PS) != 0) {
			/* JG FreeBSD has more complex treatment here */
			KKASSERT(*pde != 0);
			pmap_inval_pde(pde, pmap, sva);
			atomic_add_long(&pmap->pm_stats.resident_count,
				       -NBPDR / PAGE_SIZE);
			continue;
		}

		/*
		 * Limit our scan to either the end of the va represented
		 * by the current page table page, or to the end of the
		 * range being removed.
		 */
		if (va_next > eva)
			va_next = eva;

		/*
		 * NOTE: pmap_remove_pte() can block.
		 */
		pt_m = pmap_hold_pt_page(pde, sva);
		for (pte = pmap_pde_to_pte(pde, sva); sva != va_next; pte++,
		     sva += PAGE_SIZE) {
			if (*pte) {
				if (pmap_remove_pte(pmap, pte, 0, sva))
					break;
			}
		}
		vm_page_unhold(pt_m);
	}
	vm_object_drop(pmap->pm_pteobj);
}

/*
 * Removes this physical page from all physical maps in which it resides.
 * Reflects back modify bits to the pager.
 *
 * This routine may not be called from an interrupt.
 *
 * No requirements.
 */
static void
pmap_remove_all(vm_page_t m)
{
	pt_entry_t *pte, tpte;
	pv_entry_t pv;
	vm_object_t pmobj;
	pmap_t pmap;

#if defined(PMAP_DIAGNOSTIC)
	/*
	 * XXX this makes pmap_page_protect(NONE) illegal for non-managed
	 * pages!
	 */
	if (!pmap_initialized || (m->flags & PG_FICTITIOUS)) {
		panic("pmap_page_protect: illegal for unmanaged page, va: 0x%08llx", (long long)VM_PAGE_TO_PHYS(m));
	}
#endif

restart:
	vm_page_spin_lock(m);
	while ((pv = TAILQ_FIRST(&m->md.pv_list)) != NULL) {
		pmap = pv->pv_pmap;
		pmobj = pmap->pm_pteobj;

		/*
		 * Handle reversed lock ordering
		 */
		if (vm_object_hold_try(pmobj) == 0) {
			refcount_acquire(&pmobj->hold_count);
			vm_page_spin_unlock(m);
			vm_object_lock(pmobj);
			vm_page_spin_lock(m);
			if (pv != TAILQ_FIRST(&m->md.pv_list) ||
			    pmap != pv->pv_pmap ||
			    pmobj != pmap->pm_pteobj) {
				vm_page_spin_unlock(m);
				vm_object_drop(pmobj);
				goto restart;
			}
		}

		KKASSERT(pmap->pm_stats.resident_count > 0);
		atomic_add_long(&pmap->pm_stats.resident_count, -1);

		pte = pmap_pte(pmap, pv->pv_va);
		KKASSERT(pte != NULL);

		tpte = pmap_inval_loadandclear(pte, pmap, pv->pv_va);
		if (tpte & VPTE_WIRED)
			atomic_add_long(&pmap->pm_stats.wired_count, -1);
		KKASSERT(pmap->pm_stats.wired_count >= 0);

		if (tpte & VPTE_A)
			vm_page_flag_set(m, PG_REFERENCED);

		/*
		 * Update the vm_page_t clean and reference bits.
		 */
		if (tpte & VPTE_M) {
#if defined(PMAP_DIAGNOSTIC)
			if (pmap_nw_modified(tpte)) {
				kprintf(
	"pmap_remove_all: modified page not writable: va: 0x%lx, pte: 0x%lx\n",
				    pv->pv_va, tpte);
			}
#endif
			pmap_track_modified(pmap, pv->pv_va);
			vm_page_dirty(m);
		}
		TAILQ_REMOVE(&m->md.pv_list, pv, pv_list);
		if (TAILQ_EMPTY(&m->md.pv_list))
			vm_page_flag_clear(m, PG_MAPPED | PG_WRITEABLE);
		m->md.pv_list_count--;
		KKASSERT(m->md.pv_list_count >= 0);
		pv_entry_rb_tree_RB_REMOVE(&pmap->pm_pvroot, pv);
		atomic_add_int(&pmap->pm_generation, 1);
		vm_page_spin_unlock(m);
		pmap_unuse_pt(pmap, pv->pv_va, pv->pv_ptem);
		free_pv_entry(pv);

		vm_object_drop(pmobj);
		vm_page_spin_lock(m);
	}
	KKASSERT((m->flags & (PG_MAPPED|PG_WRITEABLE)) == 0);
	vm_page_spin_unlock(m);
}

/*
 * Removes the page from a particular pmap
 */
void
pmap_remove_specific(pmap_t pmap, vm_page_t m)
{
	pt_entry_t *pte, tpte;
	pv_entry_t pv;

	vm_object_hold(pmap->pm_pteobj);
again:
	vm_page_spin_lock(m);
	TAILQ_FOREACH(pv, &m->md.pv_list, pv_list) {
		if (pv->pv_pmap != pmap)
			continue;

		KKASSERT(pmap->pm_stats.resident_count > 0);
		atomic_add_long(&pmap->pm_stats.resident_count, -1);

		pte = pmap_pte(pmap, pv->pv_va);
		KKASSERT(pte != NULL);

		tpte = pmap_inval_loadandclear(pte, pmap, pv->pv_va);
		if (tpte & VPTE_WIRED)
			atomic_add_long(&pmap->pm_stats.wired_count, -1);
		KKASSERT(pmap->pm_stats.wired_count >= 0);

		if (tpte & VPTE_A)
			vm_page_flag_set(m, PG_REFERENCED);

		/*
		 * Update the vm_page_t clean and reference bits.
		 */
		if (tpte & VPTE_M) {
			pmap_track_modified(pmap, pv->pv_va);
			vm_page_dirty(m);
		}
		TAILQ_REMOVE(&m->md.pv_list, pv, pv_list);
		pv_entry_rb_tree_RB_REMOVE(&pmap->pm_pvroot, pv);
		atomic_add_int(&pmap->pm_generation, 1);
		m->md.pv_list_count--;
		KKASSERT(m->md.pv_list_count >= 0);
		if (TAILQ_EMPTY(&m->md.pv_list))
			vm_page_flag_clear(m, PG_MAPPED | PG_WRITEABLE);
		pmap_unuse_pt(pmap, pv->pv_va, pv->pv_ptem);
		vm_page_spin_unlock(m);
		free_pv_entry(pv);
		goto again;
	}
	vm_page_spin_unlock(m);
	vm_object_drop(pmap->pm_pteobj);
}

/*
 * Set the physical protection on the specified range of this map
 * as requested.
 *
 * This function may not be called from an interrupt if the map is
 * not the kernel_pmap.
 *
 * No requirements.
 */
void
pmap_protect(pmap_t pmap, vm_offset_t sva, vm_offset_t eva, vm_prot_t prot)
{
	vm_offset_t va_next;
	pml4_entry_t *pml4e;
	pdp_entry_t *pdpe;
	pd_entry_t ptpaddr, *pde;
	pt_entry_t *pte;
	vm_page_t pt_m;

	if (pmap == NULL)
		return;

	if ((prot & (VM_PROT_READ | VM_PROT_EXECUTE)) == VM_PROT_NONE) {
		pmap_remove(pmap, sva, eva);
		return;
	}

	if (prot & VM_PROT_WRITE)
		return;

	vm_object_hold(pmap->pm_pteobj);

	for (; sva < eva; sva = va_next) {
		pml4e = pmap_pml4e(pmap, sva);
		if ((*pml4e & VPTE_V) == 0) {
			va_next = (sva + NBPML4) & ~PML4MASK;
			if (va_next < sva)
				va_next = eva;
			continue;
		}

		pdpe = pmap_pml4e_to_pdpe(pml4e, sva);
		if ((*pdpe & VPTE_V) == 0) {
			va_next = (sva + NBPDP) & ~PDPMASK;
			if (va_next < sva)
				va_next = eva;
			continue;
		}

		va_next = (sva + NBPDR) & ~PDRMASK;
		if (va_next < sva)
			va_next = eva;

		pde = pmap_pdpe_to_pde(pdpe, sva);
		ptpaddr = *pde;

#if 0
		/*
		 * Check for large page.
		 */
		if ((ptpaddr & VPTE_PS) != 0) {
			/* JG correct? */
			pmap_clean_pde(pde, pmap, sva);
			atomic_add_long(&pmap->pm_stats.resident_count,
					-NBPDR / PAGE_SIZE);
			continue;
		}
#endif

		/*
		 * Weed out invalid mappings. Note: we assume that the page
		 * directory table is always allocated, and in kernel virtual.
		 */
		if (ptpaddr == 0)
			continue;

		if (va_next > eva)
			va_next = eva;

		pt_m = pmap_hold_pt_page(pde, sva);
		for (pte = pmap_pde_to_pte(pde, sva); sva != va_next; pte++,
		    sva += PAGE_SIZE) {
			/*
			 * Clean managed pages and also check the accessed
			 * bit.  Just remove write perms for unmanaged
			 * pages.  Be careful of races, turning off write
			 * access will force a fault rather then setting
			 * the modified bit at an unexpected time.
			 */
			pmap_track_modified(pmap, sva);
			pmap_clean_pte(pte, pmap, sva, NULL);
		}
		vm_page_unhold(pt_m);
	}
	vm_object_drop(pmap->pm_pteobj);
}

/*
 * Enter a managed page into a pmap.  If the page is not wired related pmap
 * data can be destroyed at any time for later demand-operation.
 *
 * Insert the vm_page (m) at virtual address (v) in (pmap), with the
 * specified protection, and wire the mapping if requested.
 *
 * NOTE: This routine may not lazy-evaluate or lose information.  The
 *	 page must actually be inserted into the given map NOW.
 *
 * NOTE: When entering a page at a KVA address, the pmap must be the
 *	 kernel_pmap.
 *
 * No requirements.
 */
void
pmap_enter(pmap_t pmap, vm_offset_t va, vm_page_t m, vm_prot_t prot,
	   boolean_t wired, vm_map_entry_t entry __unused)
{
	vm_paddr_t pa;
	pv_entry_t pv;
	pt_entry_t *pte;
	pt_entry_t origpte, newpte;
	vm_paddr_t opa;
	vm_page_t mpte;

	if (pmap == NULL)
		return;

	va = trunc_page(va);

	vm_object_hold(pmap->pm_pteobj);

	/*
	 * Get the page table page.   The kernel_pmap's page table pages
	 * are preallocated and have no associated vm_page_t.
	 *
	 * If not NULL, mpte will be busied and we must vm_page_wakeup()
	 * to cleanup.  There will already be at least one wire count from
	 * it being mapped into its parent.
	 */
	if (pmap == kernel_pmap) {
		mpte = NULL;
		pte = vtopte(va);
	} else {
		mpte = pmap_allocpte(pmap, va);
		pte = (void *)PHYS_TO_DMAP(mpte->phys_addr);
		pte += pmap_pte_index(va);
	}

	/*
	 * Deal with races against the kernel's real MMU by cleaning the
	 * page, even if we are re-entering the same page.
	 */
	pa = VM_PAGE_TO_PHYS(m);
	origpte = pmap_inval_loadandclear(pte, pmap, va);
	/*origpte = pmap_clean_pte(pte, pmap, va, NULL);*/
	opa = origpte & VPTE_FRAME;

	if (origpte & VPTE_PS)
		panic("pmap_enter: attempted pmap_enter on 2MB page");

	if ((origpte & (VPTE_MANAGED|VPTE_M)) == (VPTE_MANAGED|VPTE_M)) {
		vm_page_t om;

		pmap_track_modified(pmap, va);
		om = PHYS_TO_VM_PAGE(opa);
		vm_page_dirty(om);
	}

	/*
	 * Mapping has not changed, must be protection or wiring change.
	 */
	if (origpte && (opa == pa)) {
		/*
		 * Wiring change, just update stats. We don't worry about
		 * wiring PT pages as they remain resident as long as there
		 * are valid mappings in them. Hence, if a user page is wired,
		 * the PT page will be also.
		 */
		if (wired && ((origpte & VPTE_WIRED) == 0))
			atomic_add_long(&pmap->pm_stats.wired_count, 1);
		else if (!wired && (origpte & VPTE_WIRED))
			atomic_add_long(&pmap->pm_stats.wired_count, -1);

		if (origpte & VPTE_MANAGED) {
			pa |= VPTE_MANAGED;
			KKASSERT(m->flags & PG_MAPPED);
			KKASSERT((m->flags & PG_FICTITIOUS) == 0);
		} else {
			KKASSERT((m->flags & PG_FICTITIOUS));
		}
		vm_page_spin_lock(m);
		goto validate;
	}

	/*
	 * Bump the wire_count for the page table page.
	 */
	if (mpte)
		vm_page_wire_quick(mpte);

	/*
	 * Mapping has changed, invalidate old range and fall through to
	 * handle validating new mapping.  Don't inherit anything from
	 * oldpte.
	 */
	if (opa) {
		int err;
		err = pmap_remove_pte(pmap, NULL, origpte, va);
		origpte = 0;
		if (err)
			panic("pmap_enter: pte vanished, va: 0x%lx", va);
	}

	/*
	 * Enter on the PV list if part of our managed memory. Note that we
	 * raise IPL while manipulating pv_table since pmap_enter can be
	 * called at interrupt time.
	 */
	if (pmap_initialized) {
		if ((m->flags & PG_FICTITIOUS) == 0) {
			/*
			 * WARNING!  We are using m's spin-lock as a
			 *	     man's pte lock to interlock against
			 *	     pmap_page_protect() operations.
			 *
			 *	     This is a bad hack (obviously).
			 */
			pv = get_pv_entry();
			vm_page_spin_lock(m);
			pmap_insert_entry(pmap, va, mpte, m, pv);
			pa |= VPTE_MANAGED;
			/* vm_page_spin_unlock(m); */
		} else {
			vm_page_spin_lock(m);
		}
	} else {
		vm_page_spin_lock(m);
	}

	/*
	 * Increment counters
	 */
	atomic_add_long(&pmap->pm_stats.resident_count, 1);
	if (wired)
		atomic_add_long(&pmap->pm_stats.wired_count, 1);

validate:
	/*
	 * Now validate mapping with desired protection/wiring.
	 */
	newpte = (pt_entry_t)(pa | pte_prot(pmap, prot) | VPTE_V | VPTE_U);
	newpte |= VPTE_A;

	if (wired)
		newpte |= VPTE_WIRED;
//	if (pmap != kernel_pmap)
		newpte |= VPTE_U;
	if (newpte & VPTE_RW)
		vm_page_flag_set(m, PG_WRITEABLE);
	KKASSERT((newpte & VPTE_MANAGED) == 0 || (m->flags & PG_MAPPED));

	origpte = atomic_swap_long(pte, newpte);
	if (origpte & VPTE_M) {
		kprintf("pmap [M] race @ %016jx\n", va);
		atomic_set_long(pte, VPTE_M);
	}
	vm_page_spin_unlock(m);

	if (mpte)
		vm_page_wakeup(mpte);
	vm_object_drop(pmap->pm_pteobj);
}

/*
 * Make a temporary mapping for a physical address.  This is only intended
 * to be used for panic dumps.
 *
 * The caller is responsible for calling smp_invltlb().
 */
void *
pmap_kenter_temporary(vm_paddr_t pa, long i)
{
	pmap_kenter_quick(crashdumpmap + (i * PAGE_SIZE), pa);
	return ((void *)crashdumpmap);
}

#define MAX_INIT_PT (96)

/*
 * This routine preloads the ptes for a given object into the specified pmap.
 * This eliminates the blast of soft faults on process startup and
 * immediately after an mmap.
 *
 * No requirements.
 */
static int pmap_object_init_pt_callback(vm_page_t p, void *data);

void
pmap_object_init_pt(pmap_t pmap, vm_map_entry_t entry,
		    vm_offset_t addr, vm_size_t size, int limit)
{
	vm_prot_t prot = entry->protection;
	vm_object_t object = entry->ba.object;
	vm_pindex_t pindex = atop(entry->ba.offset + (addr - entry->ba.start));
	struct rb_vm_page_scan_info info;
	struct lwp *lp;
	vm_size_t psize;

	/*
	 * We can't preinit if read access isn't set or there is no pmap
	 * or object.
	 */
	if ((prot & VM_PROT_READ) == 0 || pmap == NULL || object == NULL)
		return;

	/*
	 * We can't preinit if the pmap is not the current pmap
	 */
	lp = curthread->td_lwp;
	if (lp == NULL || pmap != vmspace_pmap(lp->lwp_vmspace))
		return;

	/*
	 * Misc additional checks
	 */
	psize = x86_64_btop(size);

	if ((object->type != OBJT_VNODE) ||
		((limit & MAP_PREFAULT_PARTIAL) && (psize > MAX_INIT_PT) &&
			(object->resident_page_count > MAX_INIT_PT))) {
		return;
	}

	if (psize + pindex > object->size) {
		if (object->size < pindex)
			return;
		psize = object->size - pindex;
	}

	if (psize == 0)
		return;

	/*
	 * Use a red-black scan to traverse the requested range and load
	 * any valid pages found into the pmap.
	 *
	 * We cannot safely scan the object's memq unless we are in a
	 * critical section since interrupts can remove pages from objects.
	 */
	info.start_pindex = pindex;
	info.end_pindex = pindex + psize - 1;
	info.limit = limit;
	info.mpte = NULL;
	info.addr = addr;
	info.pmap = pmap;
	info.entry = entry;

	vm_object_hold_shared(object);
	vm_page_rb_tree_RB_SCAN(&object->rb_memq, rb_vm_page_scancmp,
				pmap_object_init_pt_callback, &info);
	vm_object_drop(object);
}

static
int
pmap_object_init_pt_callback(vm_page_t p, void *data)
{
	struct rb_vm_page_scan_info *info = data;
	vm_pindex_t rel_index;
	/*
	 * don't allow an madvise to blow away our really
	 * free pages allocating pv entries.
	 */
	if ((info->limit & MAP_PREFAULT_MADVISE) &&
		vmstats.v_free_count < vmstats.v_free_reserved) {
		    return(-1);
	}

	/*
	 * Ignore list markers and ignore pages we cannot instantly
	 * busy (while holding the object token).
	 */
	if (p->flags & PG_MARKER)
		return 0;
	if (vm_page_busy_try(p, TRUE))
		return 0;
	if (((p->valid & VM_PAGE_BITS_ALL) == VM_PAGE_BITS_ALL) &&
	    (p->flags & PG_FICTITIOUS) == 0) {
		if ((p->queue - p->pc) == PQ_CACHE)
			vm_page_deactivate(p);
		rel_index = p->pindex - info->start_pindex;
		pmap_enter(info->pmap, info->addr + x86_64_ptob(rel_index), p,
			   VM_PROT_READ, FALSE, info->entry);
	}
	vm_page_wakeup(p);
	return(0);
}

/*
 * Return TRUE if the pmap is in shape to trivially
 * pre-fault the specified address.
 *
 * Returns FALSE if it would be non-trivial or if a
 * pte is already loaded into the slot.
 *
 * No requirements.
 */
int
pmap_prefault_ok(pmap_t pmap, vm_offset_t addr)
{
	pt_entry_t *pte;
	pd_entry_t *pde;
	int ret;

	vm_object_hold(pmap->pm_pteobj);
	pde = pmap_pde(pmap, addr);
	if (pde == NULL || *pde == 0) {
		ret = 0;
	} else {
		pte = pmap_pde_to_pte(pde, addr);
		ret = (*pte) ? 0 : 1;
	}
	vm_object_drop(pmap->pm_pteobj);

	return (ret);
}

/*
 * Change the wiring attribute for a map/virtual-address pair.
 *
 * The mapping must already exist in the pmap.
 * No other requirements.
 */
vm_page_t
pmap_unwire(pmap_t pmap, vm_offset_t va)
{
	pt_entry_t *pte;
	vm_paddr_t pa;
	vm_page_t m;

	if (pmap == NULL)
		return NULL;

	vm_object_hold(pmap->pm_pteobj);
	pte = pmap_pte(pmap, va);

	if (pte == NULL || (*pte & VPTE_V) == 0) {
		vm_object_drop(pmap->pm_pteobj);
		return NULL;
	}

	/*
	 * Wiring is not a hardware characteristic so there is no need to
	 * invalidate TLB.  However, in an SMP environment we must use
	 * a locked bus cycle to update the pte (if we are not using
	 * the pmap_inval_*() API that is)... it's ok to do this for simple
	 * wiring changes.
	 */
	if (pmap_pte_w(pte))
		atomic_add_long(&pmap->pm_stats.wired_count, -1);
	/* XXX else return NULL so caller doesn't unwire m ? */
	atomic_clear_long(pte, VPTE_WIRED);

	pa = *pte & VPTE_FRAME;
	m = PHYS_TO_VM_PAGE(pa);	/* held by wired count */

	vm_object_drop(pmap->pm_pteobj);

	return m;
}

/*
 *	Copy the range specified by src_addr/len
 *	from the source map to the range dst_addr/len
 *	in the destination map.
 *
 *	This routine is only advisory and need not do anything.
 */
void
pmap_copy(pmap_t dst_pmap, pmap_t src_pmap, vm_offset_t dst_addr,
	vm_size_t len, vm_offset_t src_addr)
{
	/*
	 * XXX BUGGY.  Amoung other things srcmpte is assumed to remain
	 * valid through blocking calls, and that's just not going to
	 * be the case.
	 *
	 * FIXME!
	 */
	return;
}

/*
 * pmap_zero_page:
 *
 *	Zero the specified physical page.
 *
 *	This function may be called from an interrupt and no locking is
 *	required.
 */
void
pmap_zero_page(vm_paddr_t phys)
{
	vm_offset_t va = PHYS_TO_DMAP(phys);

	bzero((void *)va, PAGE_SIZE);
}

/*
 * pmap_zero_page:
 *
 *	Zero part of a physical page by mapping it into memory and clearing
 *	its contents with bzero.
 *
 *	off and size may not cover an area beyond a single hardware page.
 */
void
pmap_zero_page_area(vm_paddr_t phys, int off, int size)
{
	vm_offset_t virt = PHYS_TO_DMAP(phys);

	bzero((char *)virt + off, size);
}

/*
 * pmap_copy_page:
 *
 *	Copy the physical page from the source PA to the target PA.
 *	This function may be called from an interrupt.  No locking
 *	is required.
 */
void
pmap_copy_page(vm_paddr_t src, vm_paddr_t dst)
{
	vm_offset_t src_virt, dst_virt;

	src_virt = PHYS_TO_DMAP(src);
	dst_virt = PHYS_TO_DMAP(dst);
	bcopy((void *)src_virt, (void *)dst_virt, PAGE_SIZE);
}

/*
 * pmap_copy_page_frag:
 *
 *	Copy the physical page from the source PA to the target PA.
 *	This function may be called from an interrupt.  No locking
 *	is required.
 */
void
pmap_copy_page_frag(vm_paddr_t src, vm_paddr_t dst, size_t bytes)
{
	vm_offset_t src_virt, dst_virt;

	src_virt = PHYS_TO_DMAP(src);
	dst_virt = PHYS_TO_DMAP(dst);
	bcopy((char *)src_virt + (src & PAGE_MASK),
	      (char *)dst_virt + (dst & PAGE_MASK),
	      bytes);
}

/*
 * Remove all pages from specified address space this aids process
 * exit speeds.  Also, this code is special cased for current
 * process only, but can have the more generic (and slightly slower)
 * mode enabled.  This is much faster than pmap_remove in the case
 * of running down an entire address space.
 *
 * No other requirements.
 */
void
pmap_remove_pages(pmap_t pmap, vm_offset_t sva, vm_offset_t eva)
{
	pmap_remove(pmap, sva, eva);
#if 0
	pt_entry_t *pte, tpte;
	pv_entry_t pv, npv;
	vm_page_t m;
	int save_generation;

	if (pmap->pm_pteobj)
		vm_object_hold(pmap->pm_pteobj);

	pmap_invalidate_range(pmap, sva, eva);

	for (pv = TAILQ_FIRST(&pmap->pm_pvlist); pv; pv = npv) {
		if (pv->pv_va >= eva || pv->pv_va < sva) {
			npv = TAILQ_NEXT(pv, pv_plist);
			continue;
		}

		KKASSERT(pmap == pv->pv_pmap);

		pte = pmap_pte(pmap, pv->pv_va);

		/*
		 * We cannot remove wired pages from a process' mapping
		 * at this time
		 */
		if (*pte & VPTE_WIRED) {
			npv = TAILQ_NEXT(pv, pv_plist);
			continue;
		}
		tpte = pmap_inval_loadandclear(pte, pmap, pv->pv_va);

		m = PHYS_TO_VM_PAGE(tpte & VPTE_FRAME);
		vm_page_spin_lock(m);

		KASSERT(m < &vm_page_array[vm_page_array_size],
			("pmap_remove_pages: bad tpte %lx", tpte));

		KKASSERT(pmap->pm_stats.resident_count > 0);
		atomic_add_long(&pmap->pm_stats.resident_count, -1);

		/*
		 * Update the vm_page_t clean and reference bits.
		 */
		if (tpte & VPTE_M) {
			vm_page_dirty(m);
		}

		npv = TAILQ_NEXT(pv, pv_plist);
		TAILQ_REMOVE(&pmap->pm_pvlist, pv, pv_plist);
		atomic_add_int(&pmap->pm_generation, 1);
		save_generation = pmap->pm_generation;
		m->md.pv_list_count--;
		TAILQ_REMOVE(&m->md.pv_list, pv, pv_list);
		if (TAILQ_EMPTY(&m->md.pv_list))
			vm_page_flag_clear(m, PG_MAPPED | PG_WRITEABLE);
		vm_page_spin_unlock(m);

		pmap_unuse_pt(pmap, pv->pv_va, pv->pv_ptem);
		free_pv_entry(pv);

		/*
		 * Restart the scan if we blocked during the unuse or free
		 * calls and other removals were made.
		 */
		if (save_generation != pmap->pm_generation) {
			kprintf("Warning: pmap_remove_pages race-A avoided\n");
			npv = TAILQ_FIRST(&pmap->pm_pvlist);
		}
	}
	if (pmap->pm_pteobj)
		vm_object_drop(pmap->pm_pteobj);
	pmap_remove(pmap, sva, eva);
#endif
}

/*
 * pmap_testbit tests bits in active mappings of a VM page.
 */
static boolean_t
pmap_testbit(vm_page_t m, int bit)
{
	pv_entry_t pv;
	pt_entry_t *pte;

	if (!pmap_initialized || (m->flags & PG_FICTITIOUS))
		return FALSE;

	if (TAILQ_FIRST(&m->md.pv_list) == NULL)
		return FALSE;

	vm_page_spin_lock(m);
	TAILQ_FOREACH(pv, &m->md.pv_list, pv_list) {
		/*
		 * if the bit being tested is the modified bit, then
		 * mark clean_map and ptes as never
		 * modified.
		 */
		if (bit & (VPTE_A|VPTE_M))
			pmap_track_modified(pv->pv_pmap, pv->pv_va);

#if defined(PMAP_DIAGNOSTIC)
		if (pv->pv_pmap == NULL) {
			kprintf("Null pmap (tb) at va: 0x%lx\n", pv->pv_va);
			continue;
		}
#endif
		pte = pmap_pte(pv->pv_pmap, pv->pv_va);
		if (*pte & bit) {
			vm_page_spin_unlock(m);
			return TRUE;
		}
	}
	vm_page_spin_unlock(m);
	return (FALSE);
}

/*
 * This routine is used to clear bits in ptes.  Certain bits require special
 * handling, in particular (on virtual kernels) the VPTE_M (modify) bit.
 *
 * This routine is only called with certain VPTE_* bit combinations.
 */
static __inline void
pmap_clearbit(vm_page_t m, int bit)
{
	pv_entry_t pv;
	pt_entry_t *pte;
	pt_entry_t pbits;
	vm_object_t pmobj;
	pmap_t pmap;

	if (!pmap_initialized || (m->flags & PG_FICTITIOUS)) {
		if (bit == VPTE_RW)
			vm_page_flag_clear(m, PG_WRITEABLE);
		return;
	}

	/*
	 * Loop over all current mappings setting/clearing as appropos If
	 * setting RO do we need to clear the VAC?
	 */
restart:
	vm_page_spin_lock(m);
	TAILQ_FOREACH(pv, &m->md.pv_list, pv_list) {
		/*
		 * Need the pmap object lock(?)
		 */
		pmap = pv->pv_pmap;
		pmobj = pmap->pm_pteobj;

		if (vm_object_hold_try(pmobj) == 0) {
			refcount_acquire(&pmobj->hold_count);
			vm_page_spin_unlock(m);
			vm_object_lock(pmobj);
			vm_object_drop(pmobj);
			goto restart;
		}

		/*
		 * don't write protect pager mappings
		 */
		if (bit == VPTE_RW) {
			pmap_track_modified(pv->pv_pmap, pv->pv_va);
		}

#if defined(PMAP_DIAGNOSTIC)
		if (pv->pv_pmap == NULL) {
			kprintf("Null pmap (cb) at va: 0x%lx\n", pv->pv_va);
			vm_object_drop(pmobj);
			continue;
		}
#endif

		/*
		 * Careful here.  We can use a locked bus instruction to
		 * clear VPTE_A or VPTE_M safely but we need to synchronize
		 * with the target cpus when we mess with VPTE_RW.
		 *
		 * On virtual kernels we must force a new fault-on-write
		 * in the real kernel if we clear the Modify bit ourselves,
		 * otherwise the real kernel will not get a new fault and
		 * will never set our Modify bit again.
		 */
		pte = pmap_pte(pv->pv_pmap, pv->pv_va);
		if (*pte & bit) {
			if (bit == VPTE_RW) {
				/*
				 * We must also clear VPTE_M when clearing
				 * VPTE_RW and synchronize its state to
				 * the page.
				 */
				pmap_track_modified(pv->pv_pmap, pv->pv_va);
				pbits = pmap_clean_pte(pte, pv->pv_pmap,
						       pv->pv_va, m);
			} else if (bit == VPTE_M) {
				/*
				 * We must invalidate the real-kernel pte
				 * when clearing VPTE_M bit to force the
				 * real-kernel to take a new fault to re-set
				 * VPTE_M.
				 */
				atomic_clear_long(pte, VPTE_M);
				if (*pte & VPTE_RW) {
					pmap_invalidate_range(pv->pv_pmap,
						      pv->pv_va,
						      pv->pv_va + PAGE_SIZE);
				}
			} else if ((bit & (VPTE_RW|VPTE_M)) ==
				   (VPTE_RW|VPTE_M)) {
				/*
				 * We've been asked to clear W & M, I guess
				 * the caller doesn't want us to update
				 * the dirty status of the VM page.
				 */
				pmap_track_modified(pv->pv_pmap, pv->pv_va);
				pmap_clean_pte(pte, pv->pv_pmap, pv->pv_va, m);
				panic("shouldn't be called");
			} else {
				/*
				 * We've been asked to clear bits that do
				 * not interact with hardware.
				 */
				atomic_clear_long(pte, bit);
			}
		}
		vm_object_drop(pmobj);
	}
	if (bit == VPTE_RW)
		vm_page_flag_clear(m, PG_WRITEABLE);
	vm_page_spin_unlock(m);
}

/*
 * Lower the permission for all mappings to a given page.
 *
 * No other requirements.
 */
void
pmap_page_protect(vm_page_t m, vm_prot_t prot)
{
	if ((prot & VM_PROT_WRITE) == 0) {
		if (prot & (VM_PROT_READ | VM_PROT_EXECUTE)) {
			pmap_clearbit(m, VPTE_RW);
		} else {
			pmap_remove_all(m);
		}
	}
}

vm_paddr_t
pmap_phys_address(vm_pindex_t ppn)
{
	return (x86_64_ptob(ppn));
}

/*
 * Return a count of reference bits for a page, clearing those bits.
 * It is not necessary for every reference bit to be cleared, but it
 * is necessary that 0 only be returned when there are truly no
 * reference bits set.
 *
 * XXX: The exact number of bits to check and clear is a matter that
 * should be tested and standardized at some point in the future for
 * optimal aging of shared pages.
 *
 * No other requirements.
 */
int
pmap_ts_referenced(vm_page_t m)
{
	pv_entry_t pv, pvf, pvn;
	pt_entry_t *pte;
	int rtval = 0;

	if (!pmap_initialized || (m->flags & PG_FICTITIOUS))
		return (rtval);

	vm_page_spin_lock(m);
	if ((pv = TAILQ_FIRST(&m->md.pv_list)) != NULL) {
		pvf = pv;
		do {
			pvn = TAILQ_NEXT(pv, pv_list);
			TAILQ_REMOVE(&m->md.pv_list, pv, pv_list);
			TAILQ_INSERT_TAIL(&m->md.pv_list, pv, pv_list);

			pmap_track_modified(pv->pv_pmap, pv->pv_va);
			pte = pmap_pte(pv->pv_pmap, pv->pv_va);

			if (pte && (*pte & VPTE_A)) {
				atomic_clear_long(pte, VPTE_A);
				rtval++;
				if (rtval > 4) {
					break;
				}
			}
		} while ((pv = pvn) != NULL && pv != pvf);
	}
	vm_page_spin_unlock(m);

	return (rtval);
}

/*
 * Return whether or not the specified physical page was modified
 * in any physical maps.
 *
 * No other requirements.
 */
boolean_t
pmap_is_modified(vm_page_t m)
{
	boolean_t res;

	res = pmap_testbit(m, VPTE_M);

	return (res);
}

/*
 * Clear the modify bits on the specified physical page.  For the vkernel
 * we really need to clean the page, which clears VPTE_RW and VPTE_M, in
 * order to ensure that we take a fault on the next write to the page.
 * Otherwise the page may become dirty without us knowing it.
 *
 * No other requirements.
 */
void
pmap_clear_modify(vm_page_t m)
{
	pmap_clearbit(m, VPTE_RW);
}

/*
 * Clear the reference bit on the specified physical page.
 *
 * No other requirements.
 */
void
pmap_clear_reference(vm_page_t m)
{
	pmap_clearbit(m, VPTE_A);
}

/*
 * Miscellaneous support routines follow
 */
static void
x86_64_protection_init(void)
{
	uint64_t *kp;
	int prot;

	kp = protection_codes;
	for (prot = 0; prot < 8; prot++) {
		if (prot & VM_PROT_READ)
			*kp |= 0;			/* R */
		if (prot & VM_PROT_WRITE)
			*kp |= VPTE_RW;			/* R+W */
		if (prot && (prot & VM_PROT_EXECUTE) == 0)
			*kp |= VPTE_NX;			/* NX - !executable */
		++kp;
	}
}

/*
 * Sets the memory attribute for the specified page.
 */
void
pmap_page_set_memattr(vm_page_t m, vm_memattr_t ma)
{
	/* This is a vkernel, do nothing */
}

/*
 * Change the PAT attribute on an existing kernel memory map.  Caller
 * must ensure that the virtual memory in question is not accessed
 * during the adjustment.
 */
void
pmap_change_attr(vm_offset_t va, vm_size_t count, int mode)
{
	/* This is a vkernel, do nothing */
}

/*
 * Perform the pmap work for mincore
 *
 * No other requirements.
 */
int
pmap_mincore(pmap_t pmap, vm_offset_t addr)
{
	pt_entry_t *ptep, pte;
	vm_page_t m;
	int val = 0;

	vm_object_hold(pmap->pm_pteobj);
	ptep = pmap_pte(pmap, addr);

	if (ptep && (pte = *ptep) != 0) {
		vm_paddr_t pa;

		val = MINCORE_INCORE;
		if ((pte & VPTE_MANAGED) == 0)
			goto done;

		pa = pte & VPTE_FRAME;

		m = PHYS_TO_VM_PAGE(pa);

		/*
		 * Modified by us
		 */
		if (pte & VPTE_M)
			val |= MINCORE_MODIFIED|MINCORE_MODIFIED_OTHER;
		/*
		 * Modified by someone
		 */
		else if (m->dirty || pmap_is_modified(m))
			val |= MINCORE_MODIFIED_OTHER;
		/*
		 * Referenced by us
		 */
		if (pte & VPTE_A)
			val |= MINCORE_REFERENCED|MINCORE_REFERENCED_OTHER;

		/*
		 * Referenced by someone
		 */
		else if ((m->flags & PG_REFERENCED) || pmap_ts_referenced(m)) {
			val |= MINCORE_REFERENCED_OTHER;
			vm_page_flag_set(m, PG_REFERENCED);
		}
	}
done:
	vm_object_drop(pmap->pm_pteobj);

	return val;
}

/*
 * Replace p->p_vmspace with a new one.  If adjrefs is non-zero the new
 * vmspace will be ref'd and the old one will be deref'd.
 *
 * Caller must hold vmspace->vm_map.token for oldvm and newvm
 */
void
pmap_replacevm(struct proc *p, struct vmspace *newvm, int adjrefs)
{
	struct vmspace *oldvm;
	struct lwp *lp;

	oldvm = p->p_vmspace;
	if (oldvm != newvm) {
		if (adjrefs)
			vmspace_ref(newvm);
		KKASSERT((newvm->vm_refcnt & VM_REF_DELETED) == 0);
		p->p_vmspace = newvm;
		KKASSERT(p->p_nthreads == 1);
		lp = RB_ROOT(&p->p_lwp_tree);
		pmap_setlwpvm(lp, newvm);
		if (adjrefs)
			vmspace_rel(oldvm);
	}
}

/*
 * Set the vmspace for a LWP.  The vmspace is almost universally set the
 * same as the process vmspace, but virtual kernels need to swap out contexts
 * on a per-lwp basis.
 */
void
pmap_setlwpvm(struct lwp *lp, struct vmspace *newvm)
{
	struct vmspace *oldvm;
	struct pmap *pmap;

	oldvm = lp->lwp_vmspace;
	if (oldvm != newvm) {
		crit_enter();
		KKASSERT((newvm->vm_refcnt & VM_REF_DELETED) == 0);
		lp->lwp_vmspace = newvm;
		if (curthread->td_lwp == lp) {
			pmap = vmspace_pmap(newvm);
			ATOMIC_CPUMASK_ORBIT(pmap->pm_active, mycpu->gd_cpuid);
			if (pmap->pm_active_lock & CPULOCK_EXCL)
				pmap_interlock_wait(newvm);
#if defined(SWTCH_OPTIM_STATS)
			tlb_flush_count++;
#endif
			pmap = vmspace_pmap(oldvm);
			ATOMIC_CPUMASK_NANDBIT(pmap->pm_active,
					       mycpu->gd_cpuid);
		}
		crit_exit();
	}
}

/*
 * The swtch code tried to switch in a heavy weight process whos pmap
 * is locked by another cpu.  We have to wait for the lock to clear before
 * the pmap can be used.
 */
void
pmap_interlock_wait (struct vmspace *vm)
{
	pmap_t pmap = vmspace_pmap(vm);

	if (pmap->pm_active_lock & CPULOCK_EXCL) {
		crit_enter();
		while (pmap->pm_active_lock & CPULOCK_EXCL) {
			cpu_ccfence();
			vkernel_yield();
		}
		crit_exit();
	}
}

vm_offset_t
pmap_addr_hint(vm_object_t obj, vm_offset_t addr, vm_size_t size)
{

	if ((obj == NULL) || (size < NBPDR) || (obj->type != OBJT_DEVICE)) {
		return addr;
	}

	addr = roundup2(addr, NBPDR);
	return addr;
}

/*
 * Used by kmalloc/kfree, page already exists at va
 */
vm_page_t
pmap_kvtom(vm_offset_t va)
{
	vpte_t *ptep;

	KKASSERT(va >= KvaStart && va < KvaEnd);
	ptep = vtopte(va);
	return(PHYS_TO_VM_PAGE(*ptep & PG_FRAME));
}

void
pmap_object_init(vm_object_t object)
{
	/* empty */
}

void
pmap_object_free(vm_object_t object)
{
	/* empty */
}

void
pmap_pgscan(struct pmap_pgscan_info *pginfo)
{
	pmap_t pmap = pginfo->pmap;
	vm_offset_t sva = pginfo->beg_addr;
	vm_offset_t eva = pginfo->end_addr;
	vm_offset_t va_next;
	pml4_entry_t *pml4e;
	pdp_entry_t *pdpe;
	pd_entry_t ptpaddr, *pde;
	pt_entry_t *pte;
	vm_page_t pt_m;
	int stop = 0;

	vm_object_hold(pmap->pm_pteobj);

	for (; sva < eva; sva = va_next) {
		if (stop)
			break;

		pml4e = pmap_pml4e(pmap, sva);
		if ((*pml4e & VPTE_V) == 0) {
			va_next = (sva + NBPML4) & ~PML4MASK;
			if (va_next < sva)
				va_next = eva;
			continue;
		}

		pdpe = pmap_pml4e_to_pdpe(pml4e, sva);
		if ((*pdpe & VPTE_V) == 0) {
			va_next = (sva + NBPDP) & ~PDPMASK;
			if (va_next < sva)
				va_next = eva;
			continue;
		}

		va_next = (sva + NBPDR) & ~PDRMASK;
		if (va_next < sva)
			va_next = eva;

		pde = pmap_pdpe_to_pde(pdpe, sva);
		ptpaddr = *pde;

#if 0
		/*
		 * Check for large page (ignore).
		 */
		if ((ptpaddr & VPTE_PS) != 0) {
#if 0
			pmap_clean_pde(pde, pmap, sva);
			pmap->pm_stats.resident_count -= NBPDR / PAGE_SIZE;
#endif
			continue;
		}
#endif

		/*
		 * Weed out invalid mappings. Note: we assume that the page
		 * directory table is always allocated, and in kernel virtual.
		 */
		if (ptpaddr == 0)
			continue;

		if (va_next > eva)
			va_next = eva;

		pt_m = pmap_hold_pt_page(pde, sva);
		for (pte = pmap_pde_to_pte(pde, sva); sva != va_next; pte++,
		    sva += PAGE_SIZE) {
			vm_page_t m;

			if (stop)
				break;
			if ((*pte & VPTE_MANAGED) == 0)
				continue;

			m = PHYS_TO_VM_PAGE(*pte & VPTE_FRAME);
			if (vm_page_busy_try(m, TRUE) == 0) {
				if (pginfo->callback(pginfo, sva, m) < 0)
					stop = 1;
			}
		}
		vm_page_unhold(pt_m);
	}
	vm_object_drop(pmap->pm_pteobj);
}

void
pmap_maybethreaded(pmap_t pmap)
{
	/* nop */
}

/*
 * Called while page is hard-busied to clear the PG_MAPPED and PG_WRITEABLE
 * flags if able.
 *
 * vkernel code is using the old pmap style so the flags should already
 * be properly set.
 */
int
pmap_mapped_sync(vm_page_t m)
{
	return (m->flags);
}