MFC r259244:

[FreeBSD/stable/10.git] / sys / ia64 / ia64 / pmap.c

/*-
 * Copyright (c) 1991 Regents of the University of California.
 * All rights reserved.
 * Copyright (c) 1994 John S. Dyson
 * All rights reserved.
 * Copyright (c) 1994 David Greenman
 * All rights reserved.
 * Copyright (c) 1998,2000 Doug Rabson
 * 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
 *      from:   i386 Id: pmap.c,v 1.193 1998/04/19 15:22:48 bde Exp
 *              with some ideas from NetBSD's alpha pmap
 */

#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");

#include "opt_pmap.h"

#include <sys/param.h>
#include <sys/kernel.h>
#include <sys/lock.h>
#include <sys/mman.h>
#include <sys/mutex.h>
#include <sys/proc.h>
#include <sys/rwlock.h>
#include <sys/smp.h>
#include <sys/sysctl.h>
#include <sys/systm.h>

#include <vm/vm.h>
#include <vm/vm_param.h>
#include <vm/vm_page.h>
#include <vm/vm_map.h>
#include <vm/vm_object.h>
#include <vm/vm_pageout.h>
#include <vm/uma.h>

#include <machine/bootinfo.h>
#include <machine/efi.h>
#include <machine/md_var.h>
#include <machine/pal.h>

/*
 *      Manages physical address maps.
 *
 *      Since the information managed by this module is
 *      also stored by the logical address mapping module,
 *      this module may throw away valid virtual-to-physical
 *      mappings at almost any time.  However, invalidations
 *      of virtual-to-physical mappings must be done as
 *      requested.
 *
 *      In order to cope with hardware architectures which
 *      make virtual-to-physical map invalidates expensive,
 *      this module may delay invalidate or reduced protection
 *      operations until such time as they are actually
 *      necessary.  This module is given full information as
 *      to which processors are currently using which maps,
 *      and to when physical maps must be made correct.
 */

/*
 * Following the Linux model, region IDs are allocated in groups of
 * eight so that a single region ID can be used for as many RRs as we
 * want by encoding the RR number into the low bits of the ID.
 *
 * We reserve region ID 0 for the kernel and allocate the remaining
 * IDs for user pmaps.
 *
 * Region 0-3:  User virtually mapped
 * Region 4:    PBVM and special mappings
 * Region 5:    Kernel virtual memory
 * Region 6:    Direct-mapped uncacheable
 * Region 7:    Direct-mapped cacheable
 */

/* XXX move to a header. */
extern uint64_t ia64_gateway_page[];

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

#ifdef PV_STATS
#define PV_STAT(x)      do { x ; } while (0)
#else
#define PV_STAT(x)      do { } while (0)
#endif

#define pmap_accessed(lpte)             ((lpte)->pte & PTE_ACCESSED)
#define pmap_dirty(lpte)                ((lpte)->pte & PTE_DIRTY)
#define pmap_exec(lpte)                 ((lpte)->pte & PTE_AR_RX)
#define pmap_managed(lpte)              ((lpte)->pte & PTE_MANAGED)
#define pmap_ppn(lpte)                  ((lpte)->pte & PTE_PPN_MASK)
#define pmap_present(lpte)              ((lpte)->pte & PTE_PRESENT)
#define pmap_prot(lpte)                 (((lpte)->pte & PTE_PROT_MASK) >> 56)
#define pmap_wired(lpte)                ((lpte)->pte & PTE_WIRED)

#define pmap_clear_accessed(lpte)       (lpte)->pte &= ~PTE_ACCESSED
#define pmap_clear_dirty(lpte)          (lpte)->pte &= ~PTE_DIRTY
#define pmap_clear_present(lpte)        (lpte)->pte &= ~PTE_PRESENT
#define pmap_clear_wired(lpte)          (lpte)->pte &= ~PTE_WIRED

#define pmap_set_wired(lpte)            (lpte)->pte |= PTE_WIRED

/*
 * Individual PV entries are stored in per-pmap chunks.  This saves
 * space by eliminating the need to record the pmap within every PV
 * entry.
 */
#if PAGE_SIZE == 8192
#define _NPCM   6
#define _NPCPV  337
#define _NPCS   2
#elif PAGE_SIZE == 16384
#define _NPCM   11
#define _NPCPV  677
#define _NPCS   1
#endif
struct pv_chunk {
        pmap_t                  pc_pmap;
        TAILQ_ENTRY(pv_chunk)   pc_list;
        u_long                  pc_map[_NPCM];  /* bitmap; 1 = free */
        TAILQ_ENTRY(pv_chunk)   pc_lru;
        u_long                  pc_spare[_NPCS];
        struct pv_entry         pc_pventry[_NPCPV];
};

/*
 * The VHPT bucket head structure.
 */
struct ia64_bucket {
        uint64_t        chain;
        struct mtx      mutex;
        u_int           length;
};

/*
 * Statically allocated kernel pmap
 */
struct pmap kernel_pmap_store;

vm_offset_t virtual_avail;      /* VA of first avail page (after kernel bss) */
vm_offset_t virtual_end;        /* VA of last avail page (end of kernel AS) */

/*
 * Kernel virtual memory management.
 */
static int nkpt;
extern struct ia64_lpte ***ia64_kptdir;

#define KPTE_DIR0_INDEX(va) \
        (((va) >> (3*PAGE_SHIFT-8)) & ((1<<(PAGE_SHIFT-3))-1))
#define KPTE_DIR1_INDEX(va) \
        (((va) >> (2*PAGE_SHIFT-5)) & ((1<<(PAGE_SHIFT-3))-1))
#define KPTE_PTE_INDEX(va) \
        (((va) >> PAGE_SHIFT) & ((1<<(PAGE_SHIFT-5))-1))
#define NKPTEPG         (PAGE_SIZE / sizeof(struct ia64_lpte))

vm_offset_t kernel_vm_end;

/* Values for ptc.e. XXX values for SKI. */
static uint64_t pmap_ptc_e_base = 0x100000000;
static uint64_t pmap_ptc_e_count1 = 3;
static uint64_t pmap_ptc_e_count2 = 2;
static uint64_t pmap_ptc_e_stride1 = 0x2000;
static uint64_t pmap_ptc_e_stride2 = 0x100000000;

struct mtx pmap_ptc_mutex;

/*
 * Data for the RID allocator
 */
static int pmap_ridcount;
static int pmap_rididx;
static int pmap_ridmapsz;
static int pmap_ridmax;
static uint64_t *pmap_ridmap;
struct mtx pmap_ridmutex;

static struct rwlock_padalign pvh_global_lock;

/*
 * Data for the pv entry allocation mechanism
 */
static TAILQ_HEAD(pch, pv_chunk) pv_chunks = TAILQ_HEAD_INITIALIZER(pv_chunks);
static int pv_entry_count;

/*
 * Data for allocating PTEs for user processes.
 */
static uma_zone_t ptezone;

/*
 * Virtual Hash Page Table (VHPT) data.
 */
/* SYSCTL_DECL(_machdep); */
static SYSCTL_NODE(_machdep, OID_AUTO, vhpt, CTLFLAG_RD, 0, "");

struct ia64_bucket *pmap_vhpt_bucket;

int pmap_vhpt_nbuckets;
SYSCTL_INT(_machdep_vhpt, OID_AUTO, nbuckets, CTLFLAG_RD,
    &pmap_vhpt_nbuckets, 0, "");

int pmap_vhpt_log2size = 0;
TUNABLE_INT("machdep.vhpt.log2size", &pmap_vhpt_log2size);
SYSCTL_INT(_machdep_vhpt, OID_AUTO, log2size, CTLFLAG_RD,
    &pmap_vhpt_log2size, 0, "");

static int pmap_vhpt_inserts;
SYSCTL_INT(_machdep_vhpt, OID_AUTO, inserts, CTLFLAG_RD,
    &pmap_vhpt_inserts, 0, "");

static int pmap_vhpt_population(SYSCTL_HANDLER_ARGS);
SYSCTL_PROC(_machdep_vhpt, OID_AUTO, population, CTLTYPE_INT | CTLFLAG_RD,
    NULL, 0, pmap_vhpt_population, "I", "");

static struct ia64_lpte *pmap_find_vhpt(vm_offset_t va);

static void free_pv_chunk(struct pv_chunk *pc);
static void free_pv_entry(pmap_t pmap, pv_entry_t pv);
static pv_entry_t get_pv_entry(pmap_t pmap, boolean_t try);
static vm_page_t pmap_pv_reclaim(pmap_t locked_pmap);

static void     pmap_enter_quick_locked(pmap_t pmap, vm_offset_t va,
                    vm_page_t m, vm_prot_t prot);
static void     pmap_free_pte(struct ia64_lpte *pte, vm_offset_t va);
static void     pmap_invalidate_all(void);
static int      pmap_remove_pte(pmap_t pmap, struct ia64_lpte *pte,
                    vm_offset_t va, pv_entry_t pv, int freepte);
static int      pmap_remove_vhpt(vm_offset_t va);
static boolean_t pmap_try_insert_pv_entry(pmap_t pmap, vm_offset_t va,
                    vm_page_t m);

static void
pmap_initialize_vhpt(vm_offset_t vhpt)
{
        struct ia64_lpte *pte;
        u_int i;

        pte = (struct ia64_lpte *)vhpt;
        for (i = 0; i < pmap_vhpt_nbuckets; i++) {
                pte[i].pte = 0;
                pte[i].itir = 0;
                pte[i].tag = 1UL << 63; /* Invalid tag */
                pte[i].chain = (uintptr_t)(pmap_vhpt_bucket + i);
        }
}

#ifdef SMP
vm_offset_t
pmap_alloc_vhpt(void)
{
        vm_offset_t vhpt;
        vm_page_t m;
        vm_size_t size;

        size = 1UL << pmap_vhpt_log2size;
        m = vm_page_alloc_contig(NULL, 0, VM_ALLOC_SYSTEM | VM_ALLOC_NOOBJ |
            VM_ALLOC_WIRED, atop(size), 0UL, ~0UL, size, 0UL,
            VM_MEMATTR_DEFAULT);
        if (m != NULL) {
                vhpt = IA64_PHYS_TO_RR7(VM_PAGE_TO_PHYS(m));
                pmap_initialize_vhpt(vhpt);
                return (vhpt);
        }
        return (0);
}
#endif

/*
 *      Bootstrap the system enough to run with virtual memory.
 */
void
pmap_bootstrap()
{
        struct ia64_pal_result res;
        vm_offset_t base;
        size_t size;
        int i, ridbits;

        /*
         * Query the PAL Code to find the loop parameters for the
         * ptc.e instruction.
         */
        res = ia64_call_pal_static(PAL_PTCE_INFO, 0, 0, 0);
        if (res.pal_status != 0)
                panic("Can't configure ptc.e parameters");
        pmap_ptc_e_base = res.pal_result[0];
        pmap_ptc_e_count1 = res.pal_result[1] >> 32;
        pmap_ptc_e_count2 = res.pal_result[1] & ((1L<<32) - 1);
        pmap_ptc_e_stride1 = res.pal_result[2] >> 32;
        pmap_ptc_e_stride2 = res.pal_result[2] & ((1L<<32) - 1);
        if (bootverbose)
                printf("ptc.e base=0x%lx, count1=%ld, count2=%ld, "
                       "stride1=0x%lx, stride2=0x%lx\n",
                       pmap_ptc_e_base,
                       pmap_ptc_e_count1,
                       pmap_ptc_e_count2,
                       pmap_ptc_e_stride1,
                       pmap_ptc_e_stride2);

        mtx_init(&pmap_ptc_mutex, "PTC.G mutex", NULL, MTX_SPIN);

        /*
         * Setup RIDs. RIDs 0..7 are reserved for the kernel.
         *
         * We currently need at least 19 bits in the RID because PID_MAX
         * can only be encoded in 17 bits and we need RIDs for 4 regions
         * per process. With PID_MAX equalling 99999 this means that we
         * need to be able to encode 399996 (=4*PID_MAX).
         * The Itanium processor only has 18 bits and the architected
         * minimum is exactly that. So, we cannot use a PID based scheme
         * in those cases. Enter pmap_ridmap...
         * We should avoid the map when running on a processor that has
         * implemented enough bits. This means that we should pass the
         * process/thread ID to pmap. This we currently don't do, so we
         * use the map anyway. However, we don't want to allocate a map
         * that is large enough to cover the range dictated by the number
         * of bits in the RID, because that may result in a RID map of
         * 2MB in size for a 24-bit RID. A 64KB map is enough.
         * The bottomline: we create a 32KB map when the processor only
         * implements 18 bits (or when we can't figure it out). Otherwise
         * we create a 64KB map.
         */
        res = ia64_call_pal_static(PAL_VM_SUMMARY, 0, 0, 0);
        if (res.pal_status != 0) {
                if (bootverbose)
                        printf("Can't read VM Summary - assuming 18 Region ID bits\n");
                ridbits = 18; /* guaranteed minimum */
        } else {
                ridbits = (res.pal_result[1] >> 8) & 0xff;
                if (bootverbose)
                        printf("Processor supports %d Region ID bits\n",
                            ridbits);
        }
        if (ridbits > 19)
                ridbits = 19;

        pmap_ridmax = (1 << ridbits);
        pmap_ridmapsz = pmap_ridmax / 64;
        pmap_ridmap = ia64_physmem_alloc(pmap_ridmax / 8, PAGE_SIZE);
        pmap_ridmap[0] |= 0xff;
        pmap_rididx = 0;
        pmap_ridcount = 8;
        mtx_init(&pmap_ridmutex, "RID allocator lock", NULL, MTX_DEF);

        /*
         * Allocate some memory for initial kernel 'page tables'.
         */
        ia64_kptdir = ia64_physmem_alloc(PAGE_SIZE, PAGE_SIZE);
        nkpt = 0;
        kernel_vm_end = VM_INIT_KERNEL_ADDRESS;

        /*
         * Determine a valid (mappable) VHPT size.
         */
        TUNABLE_INT_FETCH("machdep.vhpt.log2size", &pmap_vhpt_log2size);
        if (pmap_vhpt_log2size == 0)
                pmap_vhpt_log2size = 20;
        else if (pmap_vhpt_log2size < 16)
                pmap_vhpt_log2size = 16;
        else if (pmap_vhpt_log2size > 28)
                pmap_vhpt_log2size = 28;
        if (pmap_vhpt_log2size & 1)
                pmap_vhpt_log2size--;

        size = 1UL << pmap_vhpt_log2size;
        base = (uintptr_t)ia64_physmem_alloc(size, size);
        if (base == 0)
                panic("Unable to allocate VHPT");

        PCPU_SET(md.vhpt, base);
        if (bootverbose)
                printf("VHPT: address=%#lx, size=%#lx\n", base, size);

        pmap_vhpt_nbuckets = size / sizeof(struct ia64_lpte);
        pmap_vhpt_bucket = ia64_physmem_alloc(pmap_vhpt_nbuckets *
            sizeof(struct ia64_bucket), PAGE_SIZE);
        for (i = 0; i < pmap_vhpt_nbuckets; i++) {
                /* Stolen memory is zeroed. */
                mtx_init(&pmap_vhpt_bucket[i].mutex, "VHPT bucket lock", NULL,
                    MTX_NOWITNESS | MTX_SPIN);
        }

        pmap_initialize_vhpt(base);
        map_vhpt(base);
        ia64_set_pta(base + (1 << 8) + (pmap_vhpt_log2size << 2) + 1);
        ia64_srlz_i();

        virtual_avail = VM_INIT_KERNEL_ADDRESS;
        virtual_end = VM_MAX_KERNEL_ADDRESS;

        /*
         * Initialize the kernel pmap (which is statically allocated).
         */
        PMAP_LOCK_INIT(kernel_pmap);
        for (i = 0; i < IA64_VM_MINKERN_REGION; i++)
                kernel_pmap->pm_rid[i] = 0;
        TAILQ_INIT(&kernel_pmap->pm_pvchunk);
        PCPU_SET(md.current_pmap, kernel_pmap);

        /*
         * Initialize the global pv list lock.
         */
        rw_init(&pvh_global_lock, "pmap pv global");

        /* Region 5 is mapped via the VHPT. */
        ia64_set_rr(IA64_RR_BASE(5), (5 << 8) | (PAGE_SHIFT << 2) | 1);

        /*
         * Clear out any random TLB entries left over from booting.
         */
        pmap_invalidate_all();

        map_gateway_page();
}

static int
pmap_vhpt_population(SYSCTL_HANDLER_ARGS)
{
        int count, error, i;

        count = 0;
        for (i = 0; i < pmap_vhpt_nbuckets; i++)
                count += pmap_vhpt_bucket[i].length;

        error = SYSCTL_OUT(req, &count, sizeof(count));
        return (error);
}

vm_offset_t
pmap_page_to_va(vm_page_t m)
{
        vm_paddr_t pa;
        vm_offset_t va;

        pa = VM_PAGE_TO_PHYS(m);
        va = (m->md.memattr == VM_MEMATTR_UNCACHEABLE) ? IA64_PHYS_TO_RR6(pa) :
            IA64_PHYS_TO_RR7(pa);
        return (va);
}

/*
 *      Initialize a vm_page's machine-dependent fields.
 */
void
pmap_page_init(vm_page_t m)
{

        TAILQ_INIT(&m->md.pv_list);
        m->md.memattr = VM_MEMATTR_DEFAULT;
}

/*
 *      Initialize the pmap module.
 *      Called by vm_init, to initialize any structures that the pmap
 *      system needs to map virtual memory.
 */
void
pmap_init(void)
{

        ptezone = uma_zcreate("PT ENTRY", sizeof (struct ia64_lpte), 
            NULL, NULL, NULL, NULL, UMA_ALIGN_PTR, UMA_ZONE_VM|UMA_ZONE_NOFREE);
}


/***************************************************
 * Manipulate TLBs for a pmap
 ***************************************************/

static void
pmap_invalidate_page(vm_offset_t va)
{
        struct ia64_lpte *pte;
        struct pcpu *pc;
        uint64_t tag;
        u_int vhpt_ofs;

        critical_enter();

        vhpt_ofs = ia64_thash(va) - PCPU_GET(md.vhpt);
        tag = ia64_ttag(va);
        STAILQ_FOREACH(pc, &cpuhead, pc_allcpu) {
                pte = (struct ia64_lpte *)(pc->pc_md.vhpt + vhpt_ofs);
                atomic_cmpset_64(&pte->tag, tag, 1UL << 63);
        }

        mtx_lock_spin(&pmap_ptc_mutex);

        ia64_ptc_ga(va, PAGE_SHIFT << 2);
        ia64_mf();
        ia64_srlz_i();

        mtx_unlock_spin(&pmap_ptc_mutex);

        ia64_invala();

        critical_exit();
}

static void
pmap_invalidate_all_1(void *arg)
{
        uint64_t addr;
        int i, j;

        critical_enter();
        addr = pmap_ptc_e_base;
        for (i = 0; i < pmap_ptc_e_count1; i++) {
                for (j = 0; j < pmap_ptc_e_count2; j++) {
                        ia64_ptc_e(addr);
                        addr += pmap_ptc_e_stride2;
                }
                addr += pmap_ptc_e_stride1;
        }
        critical_exit();
}

static void
pmap_invalidate_all(void)
{

#ifdef SMP
        if (mp_ncpus > 1) {
                smp_rendezvous(NULL, pmap_invalidate_all_1, NULL, NULL);
                return;
        }
#endif
        pmap_invalidate_all_1(NULL);
}

static uint32_t
pmap_allocate_rid(void)
{
        uint64_t bit, bits;
        int rid;

        mtx_lock(&pmap_ridmutex);
        if (pmap_ridcount == pmap_ridmax)
                panic("pmap_allocate_rid: All Region IDs used");

        /* Find an index with a free bit. */
        while ((bits = pmap_ridmap[pmap_rididx]) == ~0UL) {
                pmap_rididx++;
                if (pmap_rididx == pmap_ridmapsz)
                        pmap_rididx = 0;
        }
        rid = pmap_rididx * 64;

        /* Find a free bit. */
        bit = 1UL;
        while (bits & bit) {
                rid++;
                bit <<= 1;
        }

        pmap_ridmap[pmap_rididx] |= bit;
        pmap_ridcount++;
        mtx_unlock(&pmap_ridmutex);

        return rid;
}

static void
pmap_free_rid(uint32_t rid)
{
        uint64_t bit;
        int idx;

        idx = rid / 64;
        bit = ~(1UL << (rid & 63));

        mtx_lock(&pmap_ridmutex);
        pmap_ridmap[idx] &= bit;
        pmap_ridcount--;
        mtx_unlock(&pmap_ridmutex);
}

/***************************************************
 * Page table page management routines.....
 ***************************************************/

void
pmap_pinit0(struct pmap *pmap)
{

        PMAP_LOCK_INIT(pmap);
        /* kernel_pmap is the same as any other pmap. */
        pmap_pinit(pmap);
}

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

        for (i = 0; i < IA64_VM_MINKERN_REGION; i++)
                pmap->pm_rid[i] = pmap_allocate_rid();
        TAILQ_INIT(&pmap->pm_pvchunk);
        bzero(&pmap->pm_stats, sizeof pmap->pm_stats);
        return (1);
}

/***************************************************
 * 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.
 */
void
pmap_release(pmap_t pmap)
{
        int i;

        for (i = 0; i < IA64_VM_MINKERN_REGION; i++)
                if (pmap->pm_rid[i])
                        pmap_free_rid(pmap->pm_rid[i]);
}

/*
 * grow the number of kernel page table entries, if needed
 */
void
pmap_growkernel(vm_offset_t addr)
{
        struct ia64_lpte **dir1;
        struct ia64_lpte *leaf;
        vm_page_t nkpg;

        while (kernel_vm_end <= addr) {
                if (nkpt == PAGE_SIZE/8 + PAGE_SIZE*PAGE_SIZE/64)
                        panic("%s: out of kernel address space", __func__);

                dir1 = ia64_kptdir[KPTE_DIR0_INDEX(kernel_vm_end)];
                if (dir1 == NULL) {
                        nkpg = vm_page_alloc(NULL, nkpt++,
                            VM_ALLOC_NOOBJ|VM_ALLOC_INTERRUPT|VM_ALLOC_WIRED);
                        if (!nkpg)
                                panic("%s: cannot add dir. page", __func__);

                        dir1 = (struct ia64_lpte **)pmap_page_to_va(nkpg);
                        bzero(dir1, PAGE_SIZE);
                        ia64_kptdir[KPTE_DIR0_INDEX(kernel_vm_end)] = dir1;
                }

                nkpg = vm_page_alloc(NULL, nkpt++,
                    VM_ALLOC_NOOBJ|VM_ALLOC_INTERRUPT|VM_ALLOC_WIRED);
                if (!nkpg)
                        panic("%s: cannot add PTE page", __func__);

                leaf = (struct ia64_lpte *)pmap_page_to_va(nkpg);
                bzero(leaf, PAGE_SIZE);
                dir1[KPTE_DIR1_INDEX(kernel_vm_end)] = leaf;

                kernel_vm_end += PAGE_SIZE * NKPTEPG;
        }
}

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

CTASSERT(sizeof(struct pv_chunk) == PAGE_SIZE);

static __inline struct pv_chunk *
pv_to_chunk(pv_entry_t pv)
{

        return ((struct pv_chunk *)((uintptr_t)pv & ~(uintptr_t)PAGE_MASK));
}

#define PV_PMAP(pv) (pv_to_chunk(pv)->pc_pmap)

#define PC_FREE_FULL    0xfffffffffffffffful
#define PC_FREE_PARTIAL \
        ((1UL << (_NPCPV - sizeof(u_long) * 8 * (_NPCM - 1))) - 1)

#if PAGE_SIZE == 8192
static const u_long pc_freemask[_NPCM] = {
        PC_FREE_FULL, PC_FREE_FULL, PC_FREE_FULL,
        PC_FREE_FULL, PC_FREE_FULL, PC_FREE_PARTIAL
};
#elif PAGE_SIZE == 16384
static const u_long pc_freemask[_NPCM] = {
        PC_FREE_FULL, PC_FREE_FULL, PC_FREE_FULL,
        PC_FREE_FULL, PC_FREE_FULL, PC_FREE_FULL,
        PC_FREE_FULL, PC_FREE_FULL, PC_FREE_FULL,
        PC_FREE_FULL, PC_FREE_PARTIAL
};
#endif

static SYSCTL_NODE(_vm, OID_AUTO, pmap, CTLFLAG_RD, 0, "VM/pmap parameters");

SYSCTL_INT(_vm_pmap, OID_AUTO, pv_entry_count, CTLFLAG_RD, &pv_entry_count, 0,
    "Current number of pv entries");

#ifdef PV_STATS
static int pc_chunk_count, pc_chunk_allocs, pc_chunk_frees, pc_chunk_tryfail;

SYSCTL_INT(_vm_pmap, OID_AUTO, pc_chunk_count, CTLFLAG_RD, &pc_chunk_count, 0,
    "Current number of pv entry chunks");
SYSCTL_INT(_vm_pmap, OID_AUTO, pc_chunk_allocs, CTLFLAG_RD, &pc_chunk_allocs, 0,
    "Current number of pv entry chunks allocated");
SYSCTL_INT(_vm_pmap, OID_AUTO, pc_chunk_frees, CTLFLAG_RD, &pc_chunk_frees, 0,
    "Current number of pv entry chunks frees");
SYSCTL_INT(_vm_pmap, OID_AUTO, pc_chunk_tryfail, CTLFLAG_RD, &pc_chunk_tryfail, 0,
    "Number of times tried to get a chunk page but failed.");

static long pv_entry_frees, pv_entry_allocs;
static int pv_entry_spare;

SYSCTL_LONG(_vm_pmap, OID_AUTO, pv_entry_frees, CTLFLAG_RD, &pv_entry_frees, 0,
    "Current number of pv entry frees");
SYSCTL_LONG(_vm_pmap, OID_AUTO, pv_entry_allocs, CTLFLAG_RD, &pv_entry_allocs, 0,
    "Current number of pv entry allocs");
SYSCTL_INT(_vm_pmap, OID_AUTO, pv_entry_spare, CTLFLAG_RD, &pv_entry_spare, 0,
    "Current number of spare pv entries");
#endif

/*
 * We are in a serious low memory condition.  Resort to
 * drastic measures to free some pages so we can allocate
 * another pv entry chunk.
 */
static vm_page_t
pmap_pv_reclaim(pmap_t locked_pmap)
{
        struct pch newtail;
        struct pv_chunk *pc;
        struct ia64_lpte *pte;
        pmap_t pmap;
        pv_entry_t pv;
        vm_offset_t va;
        vm_page_t m, m_pc;
        u_long inuse;
        int bit, field, freed, idx;

        PMAP_LOCK_ASSERT(locked_pmap, MA_OWNED);
        pmap = NULL;
        m_pc = NULL;
        TAILQ_INIT(&newtail);
        while ((pc = TAILQ_FIRST(&pv_chunks)) != NULL) {
                TAILQ_REMOVE(&pv_chunks, pc, pc_lru);
                if (pmap != pc->pc_pmap) {
                        if (pmap != NULL) {
                                if (pmap != locked_pmap) {
                                        pmap_switch(locked_pmap);
                                        PMAP_UNLOCK(pmap);
                                }
                        }
                        pmap = pc->pc_pmap;
                        /* Avoid deadlock and lock recursion. */
                        if (pmap > locked_pmap)
                                PMAP_LOCK(pmap);
                        else if (pmap != locked_pmap && !PMAP_TRYLOCK(pmap)) {
                                pmap = NULL;
                                TAILQ_INSERT_TAIL(&newtail, pc, pc_lru);
                                continue;
                        }
                        pmap_switch(pmap);
                }

                /*
                 * Destroy every non-wired, 8 KB page mapping in the chunk.
                 */
                freed = 0;
                for (field = 0; field < _NPCM; field++) {
                        for (inuse = ~pc->pc_map[field] & pc_freemask[field];
                            inuse != 0; inuse &= ~(1UL << bit)) {
                                bit = ffsl(inuse) - 1;
                                idx = field * sizeof(inuse) * NBBY + bit;
                                pv = &pc->pc_pventry[idx];
                                va = pv->pv_va;
                                pte = pmap_find_vhpt(va);
                                KASSERT(pte != NULL, ("pte"));
                                if (pmap_wired(pte))
                                        continue;
                                pmap_remove_vhpt(va);
                                pmap_invalidate_page(va);
                                m = PHYS_TO_VM_PAGE(pmap_ppn(pte));
                                if (pmap_accessed(pte))
                                        vm_page_aflag_set(m, PGA_REFERENCED);
                                if (pmap_dirty(pte))
                                        vm_page_dirty(m);
                                pmap_free_pte(pte, va);
                                TAILQ_REMOVE(&m->md.pv_list, pv, pv_list);
                                if (TAILQ_EMPTY(&m->md.pv_list))
                                        vm_page_aflag_clear(m, PGA_WRITEABLE);
                                pc->pc_map[field] |= 1UL << bit;
                                freed++;
                        }
                }
                if (freed == 0) {
                        TAILQ_INSERT_TAIL(&newtail, pc, pc_lru);
                        continue;
                }
                /* Every freed mapping is for a 8 KB page. */
                pmap->pm_stats.resident_count -= freed;
                PV_STAT(pv_entry_frees += freed);
                PV_STAT(pv_entry_spare += freed);
                pv_entry_count -= freed;
                TAILQ_REMOVE(&pmap->pm_pvchunk, pc, pc_list);
                for (field = 0; field < _NPCM; field++)
                        if (pc->pc_map[field] != pc_freemask[field]) {
                                TAILQ_INSERT_HEAD(&pmap->pm_pvchunk, pc,
                                    pc_list);
                                TAILQ_INSERT_TAIL(&newtail, pc, pc_lru);

                                /*
                                 * One freed pv entry in locked_pmap is
                                 * sufficient.
                                 */
                                if (pmap == locked_pmap)
                                        goto out;
                                break;
                        }
                if (field == _NPCM) {
                        PV_STAT(pv_entry_spare -= _NPCPV);
                        PV_STAT(pc_chunk_count--);
                        PV_STAT(pc_chunk_frees++);
                        /* Entire chunk is free; return it. */
                        m_pc = PHYS_TO_VM_PAGE(IA64_RR_MASK((vm_offset_t)pc));
                        break;
                }
        }
out:
        TAILQ_CONCAT(&pv_chunks, &newtail, pc_lru);
        if (pmap != NULL) {
                if (pmap != locked_pmap) {
                        pmap_switch(locked_pmap);
                        PMAP_UNLOCK(pmap);
                }
        }
        return (m_pc);
}

/*
 * free the pv_entry back to the free list
 */
static void
free_pv_entry(pmap_t pmap, pv_entry_t pv)
{
        struct pv_chunk *pc;
        int bit, field, idx;

        rw_assert(&pvh_global_lock, RA_WLOCKED);
        PMAP_LOCK_ASSERT(pmap, MA_OWNED);
        PV_STAT(pv_entry_frees++);
        PV_STAT(pv_entry_spare++);
        pv_entry_count--;
        pc = pv_to_chunk(pv);
        idx = pv - &pc->pc_pventry[0];
        field = idx / (sizeof(u_long) * NBBY);
        bit = idx % (sizeof(u_long) * NBBY);
        pc->pc_map[field] |= 1ul << bit;
        for (idx = 0; idx < _NPCM; idx++)
                if (pc->pc_map[idx] != pc_freemask[idx]) {
                        /*
                         * 98% of the time, pc is already at the head of the
                         * list.  If it isn't already, move it to the head.
                         */
                        if (__predict_false(TAILQ_FIRST(&pmap->pm_pvchunk) !=
                            pc)) {
                                TAILQ_REMOVE(&pmap->pm_pvchunk, pc, pc_list);
                                TAILQ_INSERT_HEAD(&pmap->pm_pvchunk, pc,
                                    pc_list);
                        }
                        return;
                }
        TAILQ_REMOVE(&pmap->pm_pvchunk, pc, pc_list);
        free_pv_chunk(pc);
}

static void
free_pv_chunk(struct pv_chunk *pc)
{
        vm_page_t m;

        TAILQ_REMOVE(&pv_chunks, pc, pc_lru);
        PV_STAT(pv_entry_spare -= _NPCPV);
        PV_STAT(pc_chunk_count--);
        PV_STAT(pc_chunk_frees++);
        /* entire chunk is free, return it */
        m = PHYS_TO_VM_PAGE(IA64_RR_MASK((vm_offset_t)pc));
        vm_page_unwire(m, 0);
        vm_page_free(m);
}

/*
 * get a new pv_entry, allocating a block from the system
 * when needed.
 */
static pv_entry_t
get_pv_entry(pmap_t pmap, boolean_t try)
{
        struct pv_chunk *pc;
        pv_entry_t pv;
        vm_page_t m;
        int bit, field, idx;

        rw_assert(&pvh_global_lock, RA_WLOCKED);
        PMAP_LOCK_ASSERT(pmap, MA_OWNED);
        PV_STAT(pv_entry_allocs++);
        pv_entry_count++;
retry:
        pc = TAILQ_FIRST(&pmap->pm_pvchunk);
        if (pc != NULL) {
                for (field = 0; field < _NPCM; field++) {
                        if (pc->pc_map[field]) {
                                bit = ffsl(pc->pc_map[field]) - 1;
                                break;
                        }
                }
                if (field < _NPCM) {
                        idx = field * sizeof(pc->pc_map[field]) * NBBY + bit;
                        pv = &pc->pc_pventry[idx];
                        pc->pc_map[field] &= ~(1ul << bit);
                        /* If this was the last item, move it to tail */
                        for (field = 0; field < _NPCM; field++)
                                if (pc->pc_map[field] != 0) {
                                        PV_STAT(pv_entry_spare--);
                                        return (pv);    /* not full, return */
                                }
                        TAILQ_REMOVE(&pmap->pm_pvchunk, pc, pc_list);
                        TAILQ_INSERT_TAIL(&pmap->pm_pvchunk, pc, pc_list);
                        PV_STAT(pv_entry_spare--);
                        return (pv);
                }
        }
        /* No free items, allocate another chunk */
        m = vm_page_alloc(NULL, 0, VM_ALLOC_NORMAL | VM_ALLOC_NOOBJ |
            VM_ALLOC_WIRED);
        if (m == NULL) {
                if (try) {
                        pv_entry_count--;
                        PV_STAT(pc_chunk_tryfail++);
                        return (NULL);
                }
                m = pmap_pv_reclaim(pmap);
                if (m == NULL)
                        goto retry;
        }
        PV_STAT(pc_chunk_count++);
        PV_STAT(pc_chunk_allocs++);
        pc = (struct pv_chunk *)IA64_PHYS_TO_RR7(VM_PAGE_TO_PHYS(m));
        pc->pc_pmap = pmap;
        pc->pc_map[0] = pc_freemask[0] & ~1ul;  /* preallocated bit 0 */
        for (field = 1; field < _NPCM; field++)
                pc->pc_map[field] = pc_freemask[field];
        TAILQ_INSERT_TAIL(&pv_chunks, pc, pc_lru);
        pv = &pc->pc_pventry[0];
        TAILQ_INSERT_HEAD(&pmap->pm_pvchunk, pc, pc_list);
        PV_STAT(pv_entry_spare += _NPCPV - 1);
        return (pv);
}

/*
 * Conditionally create a pv entry.
 */
static boolean_t
pmap_try_insert_pv_entry(pmap_t pmap, vm_offset_t va, vm_page_t m)
{
        pv_entry_t pv;

        PMAP_LOCK_ASSERT(pmap, MA_OWNED);
        rw_assert(&pvh_global_lock, RA_WLOCKED);
        if ((pv = get_pv_entry(pmap, TRUE)) != NULL) {
                pv->pv_va = va;
                TAILQ_INSERT_TAIL(&m->md.pv_list, pv, pv_list);
                return (TRUE);
        } else
                return (FALSE);
}

/*
 * Add an ia64_lpte to the VHPT.
 */
static void
pmap_enter_vhpt(struct ia64_lpte *pte, vm_offset_t va)
{
        struct ia64_bucket *bckt;
        struct ia64_lpte *vhpte;
        uint64_t pte_pa;

        /* Can fault, so get it out of the way. */
        pte_pa = ia64_tpa((vm_offset_t)pte);

        vhpte = (struct ia64_lpte *)ia64_thash(va);
        bckt = (struct ia64_bucket *)vhpte->chain;

        mtx_lock_spin(&bckt->mutex);
        pte->chain = bckt->chain;
        ia64_mf();
        bckt->chain = pte_pa;

        pmap_vhpt_inserts++;
        bckt->length++;
        mtx_unlock_spin(&bckt->mutex);
}

/*
 * Remove the ia64_lpte matching va from the VHPT. Return zero if it
 * worked or an appropriate error code otherwise.
 */
static int
pmap_remove_vhpt(vm_offset_t va)
{
        struct ia64_bucket *bckt;
        struct ia64_lpte *pte;
        struct ia64_lpte *lpte;
        struct ia64_lpte *vhpte;
        uint64_t chain, tag;

        tag = ia64_ttag(va);
        vhpte = (struct ia64_lpte *)ia64_thash(va);
        bckt = (struct ia64_bucket *)vhpte->chain;

        lpte = NULL;
        mtx_lock_spin(&bckt->mutex);
        chain = bckt->chain;
        pte = (struct ia64_lpte *)IA64_PHYS_TO_RR7(chain);
        while (chain != 0 && pte->tag != tag) {
                lpte = pte;
                chain = pte->chain;
                pte = (struct ia64_lpte *)IA64_PHYS_TO_RR7(chain);
        }
        if (chain == 0) {
                mtx_unlock_spin(&bckt->mutex);
                return (ENOENT);
        }

        /* Snip this pv_entry out of the collision chain. */
        if (lpte == NULL)
                bckt->chain = pte->chain;
        else
                lpte->chain = pte->chain;
        ia64_mf();

        bckt->length--;
        mtx_unlock_spin(&bckt->mutex);
        return (0);
}

/*
 * Find the ia64_lpte for the given va, if any.
 */
static struct ia64_lpte *
pmap_find_vhpt(vm_offset_t va)
{
        struct ia64_bucket *bckt;
        struct ia64_lpte *pte;
        uint64_t chain, tag;

        tag = ia64_ttag(va);
        pte = (struct ia64_lpte *)ia64_thash(va);
        bckt = (struct ia64_bucket *)pte->chain;

        mtx_lock_spin(&bckt->mutex);
        chain = bckt->chain;
        pte = (struct ia64_lpte *)IA64_PHYS_TO_RR7(chain);
        while (chain != 0 && pte->tag != tag) {
                chain = pte->chain;
                pte = (struct ia64_lpte *)IA64_PHYS_TO_RR7(chain);
        }
        mtx_unlock_spin(&bckt->mutex);
        return ((chain != 0) ? pte : NULL);
}

/*
 * Remove an entry from the list of managed mappings.
 */
static int
pmap_remove_entry(pmap_t pmap, vm_page_t m, vm_offset_t va, pv_entry_t pv)
{

        rw_assert(&pvh_global_lock, RA_WLOCKED);
        if (!pv) {
                TAILQ_FOREACH(pv, &m->md.pv_list, pv_list) {
                        if (pmap == PV_PMAP(pv) && va == pv->pv_va) 
                                break;
                }
        }

        if (pv) {
                TAILQ_REMOVE(&m->md.pv_list, pv, pv_list);
                if (TAILQ_FIRST(&m->md.pv_list) == NULL)
                        vm_page_aflag_clear(m, PGA_WRITEABLE);

                free_pv_entry(pmap, pv);
                return 0;
        } else {
                return ENOENT;
        }
}

/*
 * Create a pv entry for page at pa for
 * (pmap, va).
 */
static void
pmap_insert_entry(pmap_t pmap, vm_offset_t va, vm_page_t m)
{
        pv_entry_t pv;

        rw_assert(&pvh_global_lock, RA_WLOCKED);
        pv = get_pv_entry(pmap, FALSE);
        pv->pv_va = va;
        TAILQ_INSERT_TAIL(&m->md.pv_list, pv, pv_list);
}

/*
 *      Routine:        pmap_extract
 *      Function:
 *              Extract the physical page address associated
 *              with the given map/virtual_address pair.
 */
vm_paddr_t
pmap_extract(pmap_t pmap, vm_offset_t va)
{
        struct ia64_lpte *pte;
        pmap_t oldpmap;
        vm_paddr_t pa;

        pa = 0;
        PMAP_LOCK(pmap);
        oldpmap = pmap_switch(pmap);
        pte = pmap_find_vhpt(va);
        if (pte != NULL && pmap_present(pte))
                pa = pmap_ppn(pte);
        pmap_switch(oldpmap);
        PMAP_UNLOCK(pmap);
        return (pa);
}

/*
 *      Routine:        pmap_extract_and_hold
 *      Function:
 *              Atomically extract and hold the physical page
 *              with the given pmap and virtual address pair
 *              if that mapping permits the given protection.
 */
vm_page_t
pmap_extract_and_hold(pmap_t pmap, vm_offset_t va, vm_prot_t prot)
{
        struct ia64_lpte *pte;
        pmap_t oldpmap;
        vm_page_t m;
        vm_paddr_t pa;

        pa = 0;
        m = NULL;
        PMAP_LOCK(pmap);
        oldpmap = pmap_switch(pmap);
retry:
        pte = pmap_find_vhpt(va);
        if (pte != NULL && pmap_present(pte) &&
            (pmap_prot(pte) & prot) == prot) {
                m = PHYS_TO_VM_PAGE(pmap_ppn(pte));
                if (vm_page_pa_tryrelock(pmap, pmap_ppn(pte), &pa))
                        goto retry;
                vm_page_hold(m);
        }
        PA_UNLOCK_COND(pa);
        pmap_switch(oldpmap);
        PMAP_UNLOCK(pmap);
        return (m);
}

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

/*
 * Find the kernel lpte for mapping the given virtual address, which
 * must be in the part of region 5 which we can cover with our kernel
 * 'page tables'.
 */
static struct ia64_lpte *
pmap_find_kpte(vm_offset_t va)
{
        struct ia64_lpte **dir1;
        struct ia64_lpte *leaf;

        KASSERT((va >> 61) == 5,
                ("kernel mapping 0x%lx not in region 5", va));
        KASSERT(va < kernel_vm_end,
                ("kernel mapping 0x%lx out of range", va));

        dir1 = ia64_kptdir[KPTE_DIR0_INDEX(va)];
        leaf = dir1[KPTE_DIR1_INDEX(va)];
        return (&leaf[KPTE_PTE_INDEX(va)]);
}

/*
 * Find a pte suitable for mapping a user-space address. If one exists 
 * in the VHPT, that one will be returned, otherwise a new pte is
 * allocated.
 */
static struct ia64_lpte *
pmap_find_pte(vm_offset_t va)
{
        struct ia64_lpte *pte;

        if (va >= VM_MAXUSER_ADDRESS)
                return pmap_find_kpte(va);

        pte = pmap_find_vhpt(va);
        if (pte == NULL) {
                pte = uma_zalloc(ptezone, M_NOWAIT | M_ZERO);
                pte->tag = 1UL << 63;
        }
        return (pte);
}

/*
 * Free a pte which is now unused. This simply returns it to the zone
 * allocator if it is a user mapping. For kernel mappings, clear the
 * valid bit to make it clear that the mapping is not currently used.
 */
static void
pmap_free_pte(struct ia64_lpte *pte, vm_offset_t va)
{
        if (va < VM_MAXUSER_ADDRESS)
                uma_zfree(ptezone, pte);
        else
                pmap_clear_present(pte);
}

static PMAP_INLINE void
pmap_pte_prot(pmap_t pm, struct ia64_lpte *pte, vm_prot_t prot)
{
        static long prot2ar[4] = {
                PTE_AR_R,               /* VM_PROT_NONE */
                PTE_AR_RW,              /* VM_PROT_WRITE */
                PTE_AR_RX|PTE_ED,       /* VM_PROT_EXECUTE */
                PTE_AR_RWX|PTE_ED       /* VM_PROT_WRITE|VM_PROT_EXECUTE */
        };

        pte->pte &= ~(PTE_PROT_MASK | PTE_PL_MASK | PTE_AR_MASK | PTE_ED);
        pte->pte |= (uint64_t)(prot & VM_PROT_ALL) << 56;
        pte->pte |= (prot == VM_PROT_NONE || pm == kernel_pmap)
            ? PTE_PL_KERN : PTE_PL_USER;
        pte->pte |= prot2ar[(prot & VM_PROT_ALL) >> 1];
}

static PMAP_INLINE void
pmap_pte_attr(struct ia64_lpte *pte, vm_memattr_t ma)
{

        pte->pte &= ~PTE_MA_MASK;
        pte->pte |= (ma & PTE_MA_MASK);
}

/*
 * Set a pte to contain a valid mapping and enter it in the VHPT. If
 * the pte was orginally valid, then its assumed to already be in the
 * VHPT.
 * This functions does not set the protection bits.  It's expected
 * that those have been set correctly prior to calling this function.
 */
static void
pmap_set_pte(struct ia64_lpte *pte, vm_offset_t va, vm_offset_t pa,
    boolean_t wired, boolean_t managed)
{

        pte->pte &= PTE_PROT_MASK | PTE_MA_MASK | PTE_PL_MASK |
            PTE_AR_MASK | PTE_ED;
        pte->pte |= PTE_PRESENT;
        pte->pte |= (managed) ? PTE_MANAGED : (PTE_DIRTY | PTE_ACCESSED);
        pte->pte |= (wired) ? PTE_WIRED : 0;
        pte->pte |= pa & PTE_PPN_MASK;

        pte->itir = PAGE_SHIFT << 2;

        pte->tag = ia64_ttag(va);
}

/*
 * Remove the (possibly managed) mapping represented by pte from the
 * given pmap.
 */
static int
pmap_remove_pte(pmap_t pmap, struct ia64_lpte *pte, vm_offset_t va,
                pv_entry_t pv, int freepte)
{
        int error;
        vm_page_t m;

        /*
         * First remove from the VHPT.
         */
        error = pmap_remove_vhpt(va);
        if (error)
                return (error);

        pmap_invalidate_page(va);

        if (pmap_wired(pte))
                pmap->pm_stats.wired_count -= 1;

        pmap->pm_stats.resident_count -= 1;
        if (pmap_managed(pte)) {
                m = PHYS_TO_VM_PAGE(pmap_ppn(pte));
                if (pmap_dirty(pte))
                        vm_page_dirty(m);
                if (pmap_accessed(pte))
                        vm_page_aflag_set(m, PGA_REFERENCED);

                error = pmap_remove_entry(pmap, m, va, pv);
        }
        if (freepte)
                pmap_free_pte(pte, va);

        return (error);
}

/*
 * Extract the physical page address associated with a kernel
 * virtual address.
 */
vm_paddr_t
pmap_kextract(vm_offset_t va)
{
        struct ia64_lpte *pte;
        uint64_t *pbvm_pgtbl;
        vm_paddr_t pa;
        u_int idx;

        KASSERT(va >= VM_MAXUSER_ADDRESS, ("Must be kernel VA"));

        /* Regions 6 and 7 are direct mapped. */
        if (va >= IA64_RR_BASE(6)) {
                pa = IA64_RR_MASK(va);
                goto out;
        }

        /* Region 5 is our KVA. Bail out if the VA is beyond our limits. */
        if (va >= kernel_vm_end)
                goto err_out;
        if (va >= VM_INIT_KERNEL_ADDRESS) {
                pte = pmap_find_kpte(va);
                pa = pmap_present(pte) ? pmap_ppn(pte) | (va & PAGE_MASK) : 0;
                goto out;
        }

        /* The PBVM page table. */
        if (va >= IA64_PBVM_PGTBL + bootinfo->bi_pbvm_pgtblsz)
                goto err_out;
        if (va >= IA64_PBVM_PGTBL) {
                pa = (va - IA64_PBVM_PGTBL) + bootinfo->bi_pbvm_pgtbl;
                goto out;
        }

        /* The PBVM itself. */
        if (va >= IA64_PBVM_BASE) {
                pbvm_pgtbl = (void *)IA64_PBVM_PGTBL;
                idx = (va - IA64_PBVM_BASE) >> IA64_PBVM_PAGE_SHIFT;
                if (idx >= (bootinfo->bi_pbvm_pgtblsz >> 3))
                        goto err_out;
                if ((pbvm_pgtbl[idx] & PTE_PRESENT) == 0)
                        goto err_out;
                pa = (pbvm_pgtbl[idx] & PTE_PPN_MASK) +
                    (va & IA64_PBVM_PAGE_MASK);
                goto out;
        }

 err_out:
        printf("XXX: %s: va=%#lx is invalid\n", __func__, va);
        pa = 0;
        /* FALLTHROUGH */

 out:
        return (pa);
}

/*
 * Add a list of wired pages to the kva this routine is only used for
 * temporary kernel mappings that do not need to have page modification
 * or references recorded.  Note that old mappings are simply written
 * over.  The page is effectively wired, but it's customary to not have
 * the PTE reflect that, nor update statistics.
 */
void
pmap_qenter(vm_offset_t va, vm_page_t *m, int count)
{
        struct ia64_lpte *pte;
        int i;

        for (i = 0; i < count; i++) {
                pte = pmap_find_kpte(va);
                if (pmap_present(pte))
                        pmap_invalidate_page(va);
                else
                        pmap_enter_vhpt(pte, va);
                pmap_pte_prot(kernel_pmap, pte, VM_PROT_ALL);
                pmap_pte_attr(pte, m[i]->md.memattr);
                pmap_set_pte(pte, va, VM_PAGE_TO_PHYS(m[i]), FALSE, FALSE);
                va += PAGE_SIZE;
        }
}

/*
 * this routine jerks page mappings from the
 * kernel -- it is meant only for temporary mappings.
 */
void
pmap_qremove(vm_offset_t va, int count)
{
        struct ia64_lpte *pte;
        int i;

        for (i = 0; i < count; i++) {
                pte = pmap_find_kpte(va);
                if (pmap_present(pte)) {
                        pmap_remove_vhpt(va);
                        pmap_invalidate_page(va);
                        pmap_clear_present(pte);
                }
                va += PAGE_SIZE;
        }
}

/*
 * Add a wired page to the kva.  As for pmap_qenter(), it's customary
 * to not have the PTE reflect that, nor update statistics.
 */
void 
pmap_kenter(vm_offset_t va, vm_offset_t pa)
{
        struct ia64_lpte *pte;

        pte = pmap_find_kpte(va);
        if (pmap_present(pte))
                pmap_invalidate_page(va);
        else
                pmap_enter_vhpt(pte, va);
        pmap_pte_prot(kernel_pmap, pte, VM_PROT_ALL);
        pmap_pte_attr(pte, VM_MEMATTR_DEFAULT);
        pmap_set_pte(pte, va, pa, FALSE, FALSE);
}

/*
 * Remove a page from the kva
 */
void
pmap_kremove(vm_offset_t va)
{
        struct ia64_lpte *pte;

        pte = pmap_find_kpte(va);
        if (pmap_present(pte)) {
                pmap_remove_vhpt(va);
                pmap_invalidate_page(va);
                pmap_clear_present(pte);
        }
}

/*
 *      Used to map a range of physical addresses into kernel
 *      virtual address space.
 *
 *      The value passed in '*virt' is a suggested virtual address for
 *      the mapping. Architectures which can support a direct-mapped
 *      physical to virtual region can return the appropriate address
 *      within that region, leaving '*virt' unchanged. Other
 *      architectures should map the pages starting at '*virt' and
 *      update '*virt' with the first usable address after the mapped
 *      region.
 */
vm_offset_t
pmap_map(vm_offset_t *virt, vm_offset_t start, vm_offset_t end, int prot)
{
        return IA64_PHYS_TO_RR7(start);
}

/*
 *      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.
 *
 *      Sparsely used ranges are inefficiently removed.  The VHPT is
 *      probed for every page within the range.  XXX
 */
void
pmap_remove(pmap_t pmap, vm_offset_t sva, vm_offset_t eva)
{
        pmap_t oldpmap;
        vm_offset_t va;
        struct ia64_lpte *pte;

        /*
         * Perform an unsynchronized read.  This is, however, safe.
         */
        if (pmap->pm_stats.resident_count == 0)
                return;

        rw_wlock(&pvh_global_lock);
        PMAP_LOCK(pmap);
        oldpmap = pmap_switch(pmap);
        for (va = sva; va < eva; va += PAGE_SIZE) {
                pte = pmap_find_vhpt(va);
                if (pte != NULL)
                        pmap_remove_pte(pmap, pte, va, 0, 1);
        }
        rw_wunlock(&pvh_global_lock);
        pmap_switch(oldpmap);
        PMAP_UNLOCK(pmap);
}

/*
 *      Routine:        pmap_remove_all
 *      Function:
 *              Removes this physical page from
 *              all physical maps in which it resides.
 *              Reflects back modify bits to the pager.
 *
 *      Notes:
 *              Original versions of this routine were very
 *              inefficient because they iteratively called
 *              pmap_remove (slow...)
 */

void
pmap_remove_all(vm_page_t m)
{
        pmap_t oldpmap;
        pv_entry_t pv;

        KASSERT((m->oflags & VPO_UNMANAGED) == 0,
            ("pmap_remove_all: page %p is not managed", m));
        rw_wlock(&pvh_global_lock);
        while ((pv = TAILQ_FIRST(&m->md.pv_list)) != NULL) {
                struct ia64_lpte *pte;
                pmap_t pmap = PV_PMAP(pv);
                vm_offset_t va = pv->pv_va;

                PMAP_LOCK(pmap);
                oldpmap = pmap_switch(pmap);
                pte = pmap_find_vhpt(va);
                KASSERT(pte != NULL, ("pte"));
                if (pmap_ppn(pte) != VM_PAGE_TO_PHYS(m))
                        panic("pmap_remove_all: pv_table for %lx is inconsistent", VM_PAGE_TO_PHYS(m));
                pmap_remove_pte(pmap, pte, va, pv, 1);
                pmap_switch(oldpmap);
                PMAP_UNLOCK(pmap);
        }
        vm_page_aflag_clear(m, PGA_WRITEABLE);
        rw_wunlock(&pvh_global_lock);
}

/*
 *      Set the physical protection on the
 *      specified range of this map as requested.
 */
void
pmap_protect(pmap_t pmap, vm_offset_t sva, vm_offset_t eva, vm_prot_t prot)
{
        pmap_t oldpmap;
        struct ia64_lpte *pte;

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

        if ((prot & (VM_PROT_WRITE|VM_PROT_EXECUTE)) ==
            (VM_PROT_WRITE|VM_PROT_EXECUTE))
                return;

        if ((sva & PAGE_MASK) || (eva & PAGE_MASK))
                panic("pmap_protect: unaligned addresses");

        PMAP_LOCK(pmap);
        oldpmap = pmap_switch(pmap);
        for ( ; sva < eva; sva += PAGE_SIZE) {
                /* If page is invalid, skip this page */
                pte = pmap_find_vhpt(sva);
                if (pte == NULL)
                        continue;

                /* If there's no change, skip it too */
                if (pmap_prot(pte) == prot)
                        continue;

                if ((prot & VM_PROT_WRITE) == 0 &&
                    pmap_managed(pte) && pmap_dirty(pte)) {
                        vm_paddr_t pa = pmap_ppn(pte);
                        vm_page_t m = PHYS_TO_VM_PAGE(pa);

                        vm_page_dirty(m);
                        pmap_clear_dirty(pte);
                }

                if (prot & VM_PROT_EXECUTE)
                        ia64_sync_icache(sva, PAGE_SIZE);

                pmap_pte_prot(pmap, pte, prot);
                pmap_invalidate_page(sva);
        }
        pmap_switch(oldpmap);
        PMAP_UNLOCK(pmap);
}

/*
 *      Insert the given physical page (p) at
 *      the specified virtual address (v) in the
 *      target physical map with the protection requested.
 *
 *      If specified, the page will be wired down, meaning
 *      that the related pte can not be reclaimed.
 *
 *      NB:  This is the only routine which MAY NOT lazy-evaluate
 *      or lose information.  That is, this routine must actually
 *      insert this page into the given map NOW.
 */
void
pmap_enter(pmap_t pmap, vm_offset_t va, vm_prot_t access, vm_page_t m,
    vm_prot_t prot, boolean_t wired)
{
        pmap_t oldpmap;
        vm_offset_t pa;
        vm_offset_t opa;
        struct ia64_lpte origpte;
        struct ia64_lpte *pte;
        boolean_t icache_inval, managed;

        rw_wlock(&pvh_global_lock);
        PMAP_LOCK(pmap);
        oldpmap = pmap_switch(pmap);

        va &= ~PAGE_MASK;
        KASSERT(va <= VM_MAX_KERNEL_ADDRESS, ("pmap_enter: toobig"));
        KASSERT((m->oflags & VPO_UNMANAGED) != 0 || vm_page_xbusied(m),
            ("pmap_enter: page %p is not busy", m));

        /*
         * Find (or create) a pte for the given mapping.
         */
        while ((pte = pmap_find_pte(va)) == NULL) {
                pmap_switch(oldpmap);
                PMAP_UNLOCK(pmap);
                rw_wunlock(&pvh_global_lock);
                VM_WAIT;
                rw_wlock(&pvh_global_lock);
                PMAP_LOCK(pmap);
                oldpmap = pmap_switch(pmap);
        }
        origpte = *pte;
        if (!pmap_present(pte)) {
                opa = ~0UL;
                pmap_enter_vhpt(pte, va);
        } else
                opa = pmap_ppn(pte);
        managed = FALSE;
        pa = VM_PAGE_TO_PHYS(m);

        icache_inval = (prot & VM_PROT_EXECUTE) ? TRUE : FALSE;

        /*
         * Mapping has not changed, must be protection or wiring change.
         */
        if (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 && !pmap_wired(&origpte))
                        pmap->pm_stats.wired_count++;
                else if (!wired && pmap_wired(&origpte))
                        pmap->pm_stats.wired_count--;

                managed = (pmap_managed(&origpte)) ? TRUE : FALSE;

                /*
                 * We might be turning off write access to the page,
                 * so we go ahead and sense modify status. Otherwise,
                 * we can avoid I-cache invalidation if the page
                 * already allowed execution.
                 */
                if (managed && pmap_dirty(&origpte))
                        vm_page_dirty(m);
                else if (pmap_exec(&origpte))
                        icache_inval = FALSE;

                pmap_invalidate_page(va);
                goto validate;
        }

        /*
         * Mapping has changed, invalidate old range and fall
         * through to handle validating new mapping.
         */
        if (opa != ~0UL) {
                pmap_remove_pte(pmap, pte, va, 0, 0);
                pmap_enter_vhpt(pte, va);
        }

        /*
         * Enter on the PV list if part of our managed memory.
         */
        if ((m->oflags & VPO_UNMANAGED) == 0) {
                KASSERT(va < kmi.clean_sva || va >= kmi.clean_eva,
                    ("pmap_enter: managed mapping within the clean submap"));
                pmap_insert_entry(pmap, va, m);
                managed = TRUE;
        }

        /*
         * Increment counters
         */
        pmap->pm_stats.resident_count++;
        if (wired)
                pmap->pm_stats.wired_count++;

validate:

        /*
         * Now validate mapping with desired protection/wiring. This
         * adds the pte to the VHPT if necessary.
         */
        pmap_pte_prot(pmap, pte, prot);
        pmap_pte_attr(pte, m->md.memattr);
        pmap_set_pte(pte, va, pa, wired, managed);

        /* Invalidate the I-cache when needed. */
        if (icache_inval)
                ia64_sync_icache(va, PAGE_SIZE);

        if ((prot & VM_PROT_WRITE) != 0 && managed)
                vm_page_aflag_set(m, PGA_WRITEABLE);
        rw_wunlock(&pvh_global_lock);
        pmap_switch(oldpmap);
        PMAP_UNLOCK(pmap);
}

/*
 * Maps a sequence of resident pages belonging to the same object.
 * The sequence begins with the given page m_start.  This page is
 * mapped at the given virtual address start.  Each subsequent page is
 * mapped at a virtual address that is offset from start by the same
 * amount as the page is offset from m_start within the object.  The
 * last page in the sequence is the page with the largest offset from
 * m_start that can be mapped at a virtual address less than the given
 * virtual address end.  Not every virtual page between start and end
 * is mapped; only those for which a resident page exists with the
 * corresponding offset from m_start are mapped.
 */
void
pmap_enter_object(pmap_t pmap, vm_offset_t start, vm_offset_t end,
    vm_page_t m_start, vm_prot_t prot)
{
        pmap_t oldpmap;
        vm_page_t m;
        vm_pindex_t diff, psize;

        VM_OBJECT_ASSERT_LOCKED(m_start->object);

        psize = atop(end - start);
        m = m_start;
        rw_wlock(&pvh_global_lock);
        PMAP_LOCK(pmap);
        oldpmap = pmap_switch(pmap);
        while (m != NULL && (diff = m->pindex - m_start->pindex) < psize) {
                pmap_enter_quick_locked(pmap, start + ptoa(diff), m, prot);
                m = TAILQ_NEXT(m, listq);
        }
        rw_wunlock(&pvh_global_lock);
        pmap_switch(oldpmap);
        PMAP_UNLOCK(pmap);
}

/*
 * this code makes some *MAJOR* assumptions:
 * 1. Current pmap & pmap exists.
 * 2. Not wired.
 * 3. Read access.
 * 4. No page table pages.
 * but is *MUCH* faster than pmap_enter...
 */

void
pmap_enter_quick(pmap_t pmap, vm_offset_t va, vm_page_t m, vm_prot_t prot)
{
        pmap_t oldpmap;

        rw_wlock(&pvh_global_lock);
        PMAP_LOCK(pmap);
        oldpmap = pmap_switch(pmap);
        pmap_enter_quick_locked(pmap, va, m, prot);
        rw_wunlock(&pvh_global_lock);
        pmap_switch(oldpmap);
        PMAP_UNLOCK(pmap);
}

static void
pmap_enter_quick_locked(pmap_t pmap, vm_offset_t va, vm_page_t m,
    vm_prot_t prot)
{
        struct ia64_lpte *pte;
        boolean_t managed;

        KASSERT(va < kmi.clean_sva || va >= kmi.clean_eva ||
            (m->oflags & VPO_UNMANAGED) != 0,
            ("pmap_enter_quick_locked: managed mapping within the clean submap"));
        rw_assert(&pvh_global_lock, RA_WLOCKED);
        PMAP_LOCK_ASSERT(pmap, MA_OWNED);

        if ((pte = pmap_find_pte(va)) == NULL)
                return;

        if (!pmap_present(pte)) {
                /* Enter on the PV list if the page is managed. */
                if ((m->oflags & VPO_UNMANAGED) == 0) {
                        if (!pmap_try_insert_pv_entry(pmap, va, m)) {
                                pmap_free_pte(pte, va);
                                return;
                        }
                        managed = TRUE;
                } else
                        managed = FALSE;

                /* Increment counters. */
                pmap->pm_stats.resident_count++;

                /* Initialise with R/O protection and enter into VHPT. */
                pmap_enter_vhpt(pte, va);
                pmap_pte_prot(pmap, pte,
                    prot & (VM_PROT_READ | VM_PROT_EXECUTE));
                pmap_pte_attr(pte, m->md.memattr);
                pmap_set_pte(pte, va, VM_PAGE_TO_PHYS(m), FALSE, managed);

                if (prot & VM_PROT_EXECUTE)
                        ia64_sync_icache(va, PAGE_SIZE);
        }
}

/*
 * pmap_object_init_pt 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.
 */
void
pmap_object_init_pt(pmap_t pmap, vm_offset_t addr,
                    vm_object_t object, vm_pindex_t pindex,
                    vm_size_t size)
{

        VM_OBJECT_ASSERT_WLOCKED(object);
        KASSERT(object->type == OBJT_DEVICE || object->type == OBJT_SG,
            ("pmap_object_init_pt: non-device object"));
}

/*
 *      Routine:        pmap_change_wiring
 *      Function:       Change the wiring attribute for a map/virtual-address
 *                      pair.
 *      In/out conditions:
 *                      The mapping must already exist in the pmap.
 */
void
pmap_change_wiring(pmap, va, wired)
        register pmap_t pmap;
        vm_offset_t va;
        boolean_t wired;
{
        pmap_t oldpmap;
        struct ia64_lpte *pte;

        PMAP_LOCK(pmap);
        oldpmap = pmap_switch(pmap);

        pte = pmap_find_vhpt(va);
        KASSERT(pte != NULL, ("pte"));
        if (wired && !pmap_wired(pte)) {
                pmap->pm_stats.wired_count++;
                pmap_set_wired(pte);
        } else if (!wired && pmap_wired(pte)) {
                pmap->pm_stats.wired_count--;
                pmap_clear_wired(pte);
        }

        pmap_switch(oldpmap);
        PMAP_UNLOCK(pmap);
}



/*
 *      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)
{
}       


/*
 *      pmap_zero_page zeros the specified hardware page by
 *      mapping it into virtual memory and using bzero to clear
 *      its contents.
 */

void
pmap_zero_page(vm_page_t m)
{
        void *p;

        p = (void *)pmap_page_to_va(m);
        bzero(p, PAGE_SIZE);
}


/*
 *      pmap_zero_page_area zeros the specified hardware page by
 *      mapping it into virtual memory and using bzero to clear
 *      its contents.
 *
 *      off and size must reside within a single page.
 */

void
pmap_zero_page_area(vm_page_t m, int off, int size)
{
        char *p;

        p = (void *)pmap_page_to_va(m);
        bzero(p + off, size);
}


/*
 *      pmap_zero_page_idle zeros the specified hardware page by
 *      mapping it into virtual memory and using bzero to clear
 *      its contents.  This is for the vm_idlezero process.
 */

void
pmap_zero_page_idle(vm_page_t m)
{
        void *p;

        p = (void *)pmap_page_to_va(m);
        bzero(p, PAGE_SIZE);
}


/*
 *      pmap_copy_page copies the specified (machine independent)
 *      page by mapping the page into virtual memory and using
 *      bcopy to copy the page, one machine dependent page at a
 *      time.
 */
void
pmap_copy_page(vm_page_t msrc, vm_page_t mdst)
{
        void *dst, *src;

        src = (void *)pmap_page_to_va(msrc);
        dst = (void *)pmap_page_to_va(mdst);
        bcopy(src, dst, PAGE_SIZE);
}

int unmapped_buf_allowed;

void
pmap_copy_pages(vm_page_t ma[], vm_offset_t a_offset, vm_page_t mb[],
    vm_offset_t b_offset, int xfersize)
{
        void *a_cp, *b_cp;
        vm_offset_t a_pg_offset, b_pg_offset;
        int cnt;

        while (xfersize > 0) {
                a_pg_offset = a_offset & PAGE_MASK;
                cnt = min(xfersize, PAGE_SIZE - a_pg_offset);
                a_cp = (char *)pmap_page_to_va(ma[a_offset >> PAGE_SHIFT]) +
                    a_pg_offset;
                b_pg_offset = b_offset & PAGE_MASK;
                cnt = min(cnt, PAGE_SIZE - b_pg_offset);
                b_cp = (char *)pmap_page_to_va(mb[b_offset >> PAGE_SHIFT]) +
                    b_pg_offset;
                bcopy(a_cp, b_cp, cnt);
                a_offset += cnt;
                b_offset += cnt;
                xfersize -= cnt;
        }
}

/*
 * Returns true if the pmap's pv is one of the first
 * 16 pvs linked to from this page.  This count may
 * be changed upwards or downwards in the future; it
 * is only necessary that true be returned for a small
 * subset of pmaps for proper page aging.
 */
boolean_t
pmap_page_exists_quick(pmap_t pmap, vm_page_t m)
{
        pv_entry_t pv;
        int loops = 0;
        boolean_t rv;

        KASSERT((m->oflags & VPO_UNMANAGED) == 0,
            ("pmap_page_exists_quick: page %p is not managed", m));
        rv = FALSE;
        rw_wlock(&pvh_global_lock);
        TAILQ_FOREACH(pv, &m->md.pv_list, pv_list) {
                if (PV_PMAP(pv) == pmap) {
                        rv = TRUE;
                        break;
                }
                loops++;
                if (loops >= 16)
                        break;
        }
        rw_wunlock(&pvh_global_lock);
        return (rv);
}

/*
 *      pmap_page_wired_mappings:
 *
 *      Return the number of managed mappings to the given physical page
 *      that are wired.
 */
int
pmap_page_wired_mappings(vm_page_t m)
{
        struct ia64_lpte *pte;
        pmap_t oldpmap, pmap;
        pv_entry_t pv;
        int count;

        count = 0;
        if ((m->oflags & VPO_UNMANAGED) != 0)
                return (count);
        rw_wlock(&pvh_global_lock);
        TAILQ_FOREACH(pv, &m->md.pv_list, pv_list) {
                pmap = PV_PMAP(pv);
                PMAP_LOCK(pmap);
                oldpmap = pmap_switch(pmap);
                pte = pmap_find_vhpt(pv->pv_va);
                KASSERT(pte != NULL, ("pte"));
                if (pmap_wired(pte))
                        count++;
                pmap_switch(oldpmap);
                PMAP_UNLOCK(pmap);
        }
        rw_wunlock(&pvh_global_lock);
        return (count);
}

/*
 * 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.
 */
void
pmap_remove_pages(pmap_t pmap)
{
        struct pv_chunk *pc, *npc;
        struct ia64_lpte *pte;
        pmap_t oldpmap;
        pv_entry_t pv;
        vm_offset_t va;
        vm_page_t m;
        u_long inuse, bitmask;
        int allfree, bit, field, idx;

        rw_wlock(&pvh_global_lock);
        PMAP_LOCK(pmap);
        oldpmap = pmap_switch(pmap);
        TAILQ_FOREACH_SAFE(pc, &pmap->pm_pvchunk, pc_list, npc) {
                allfree = 1;
                for (field = 0; field < _NPCM; field++) {
                        inuse = ~pc->pc_map[field] & pc_freemask[field];
                        while (inuse != 0) {
                                bit = ffsl(inuse) - 1;
                                bitmask = 1UL << bit;
                                idx = field * sizeof(inuse) * NBBY + bit;
                                pv = &pc->pc_pventry[idx];
                                inuse &= ~bitmask;
                                va = pv->pv_va;
                                pte = pmap_find_vhpt(va);
                                KASSERT(pte != NULL, ("pte"));
                                if (pmap_wired(pte)) {
                                        allfree = 0;
                                        continue;
                                }
                                pmap_remove_vhpt(va);
                                pmap_invalidate_page(va);
                                m = PHYS_TO_VM_PAGE(pmap_ppn(pte));
                                if (pmap_dirty(pte))
                                        vm_page_dirty(m);
                                pmap_free_pte(pte, va);
                                /* Mark free */
                                PV_STAT(pv_entry_frees++);
                                PV_STAT(pv_entry_spare++);
                                pv_entry_count--;
                                pc->pc_map[field] |= bitmask;
                                pmap->pm_stats.resident_count--;
                                TAILQ_REMOVE(&m->md.pv_list, pv, pv_list);
                                if (TAILQ_EMPTY(&m->md.pv_list))
                                        vm_page_aflag_clear(m, PGA_WRITEABLE);
                        }
                }
                if (allfree) {
                        TAILQ_REMOVE(&pmap->pm_pvchunk, pc, pc_list);
                        free_pv_chunk(pc);
                }
        }
        pmap_switch(oldpmap);
        PMAP_UNLOCK(pmap);
        rw_wunlock(&pvh_global_lock);
}

/*
 *      pmap_ts_referenced:
 *
 *      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.
 */
int
pmap_ts_referenced(vm_page_t m)
{
        struct ia64_lpte *pte;
        pmap_t oldpmap, pmap;
        pv_entry_t pv;
        int count = 0;

        KASSERT((m->oflags & VPO_UNMANAGED) == 0,
            ("pmap_ts_referenced: page %p is not managed", m));
        rw_wlock(&pvh_global_lock);
        TAILQ_FOREACH(pv, &m->md.pv_list, pv_list) {
                pmap = PV_PMAP(pv);
                PMAP_LOCK(pmap);
                oldpmap = pmap_switch(pmap);
                pte = pmap_find_vhpt(pv->pv_va);
                KASSERT(pte != NULL, ("pte"));
                if (pmap_accessed(pte)) {
                        count++;
                        pmap_clear_accessed(pte);
                        pmap_invalidate_page(pv->pv_va);
                }
                pmap_switch(oldpmap);
                PMAP_UNLOCK(pmap);
        }
        rw_wunlock(&pvh_global_lock);
        return (count);
}

/*
 *      pmap_is_modified:
 *
 *      Return whether or not the specified physical page was modified
 *      in any physical maps.
 */
boolean_t
pmap_is_modified(vm_page_t m)
{
        struct ia64_lpte *pte;
        pmap_t oldpmap, pmap;
        pv_entry_t pv;
        boolean_t rv;

        KASSERT((m->oflags & VPO_UNMANAGED) == 0,
            ("pmap_is_modified: page %p is not managed", m));
        rv = FALSE;

        /*
         * If the page is not exclusive busied, then PGA_WRITEABLE cannot be
         * concurrently set while the object is locked.  Thus, if PGA_WRITEABLE
         * is clear, no PTEs can be dirty.
         */
        VM_OBJECT_ASSERT_WLOCKED(m->object);
        if (!vm_page_xbusied(m) && (m->aflags & PGA_WRITEABLE) == 0)
                return (rv);
        rw_wlock(&pvh_global_lock);
        TAILQ_FOREACH(pv, &m->md.pv_list, pv_list) {
                pmap = PV_PMAP(pv);
                PMAP_LOCK(pmap);
                oldpmap = pmap_switch(pmap);
                pte = pmap_find_vhpt(pv->pv_va);
                pmap_switch(oldpmap);
                KASSERT(pte != NULL, ("pte"));
                rv = pmap_dirty(pte) ? TRUE : FALSE;
                PMAP_UNLOCK(pmap);
                if (rv)
                        break;
        }
        rw_wunlock(&pvh_global_lock);
        return (rv);
}

/*
 *      pmap_is_prefaultable:
 *
 *      Return whether or not the specified virtual address is elgible
 *      for prefault.
 */
boolean_t
pmap_is_prefaultable(pmap_t pmap, vm_offset_t addr)
{
        struct ia64_lpte *pte;

        pte = pmap_find_vhpt(addr);
        if (pte != NULL && pmap_present(pte))
                return (FALSE);
        return (TRUE);
}

/*
 *      pmap_is_referenced:
 *
 *      Return whether or not the specified physical page was referenced
 *      in any physical maps.
 */
boolean_t
pmap_is_referenced(vm_page_t m)
{
        struct ia64_lpte *pte;
        pmap_t oldpmap, pmap;
        pv_entry_t pv;
        boolean_t rv;

        KASSERT((m->oflags & VPO_UNMANAGED) == 0,
            ("pmap_is_referenced: page %p is not managed", m));
        rv = FALSE;
        rw_wlock(&pvh_global_lock);
        TAILQ_FOREACH(pv, &m->md.pv_list, pv_list) {
                pmap = PV_PMAP(pv);
                PMAP_LOCK(pmap);
                oldpmap = pmap_switch(pmap);
                pte = pmap_find_vhpt(pv->pv_va);
                pmap_switch(oldpmap);
                KASSERT(pte != NULL, ("pte"));
                rv = pmap_accessed(pte) ? TRUE : FALSE;
                PMAP_UNLOCK(pmap);
                if (rv)
                        break;
        }
        rw_wunlock(&pvh_global_lock);
        return (rv);
}

/*
 *      Apply the given advice to the specified range of addresses within the
 *      given pmap.  Depending on the advice, clear the referenced and/or
 *      modified flags in each mapping and set the mapped page's dirty field.
 */
void
pmap_advise(pmap_t pmap, vm_offset_t sva, vm_offset_t eva, int advice)
{
        struct ia64_lpte *pte;
        pmap_t oldpmap;
        vm_page_t m;

        PMAP_LOCK(pmap);
        oldpmap = pmap_switch(pmap);
        for (; sva < eva; sva += PAGE_SIZE) {
                /* If page is invalid, skip this page. */
                pte = pmap_find_vhpt(sva);
                if (pte == NULL)
                        continue;

                /* If it isn't managed, skip it too. */
                if (!pmap_managed(pte))
                        continue;

                /* Clear its modified and referenced bits. */
                if (pmap_dirty(pte)) {
                        if (advice == MADV_DONTNEED) {
                                /*
                                 * Future calls to pmap_is_modified() can be
                                 * avoided by making the page dirty now.
                                 */
                                m = PHYS_TO_VM_PAGE(pmap_ppn(pte));
                                vm_page_dirty(m);
                        }
                        pmap_clear_dirty(pte);
                } else if (!pmap_accessed(pte))
                        continue;
                pmap_clear_accessed(pte);
                pmap_invalidate_page(sva);
        }
        pmap_switch(oldpmap);
        PMAP_UNLOCK(pmap);
}

/*
 *      Clear the modify bits on the specified physical page.
 */
void
pmap_clear_modify(vm_page_t m)
{
        struct ia64_lpte *pte;
        pmap_t oldpmap, pmap;
        pv_entry_t pv;

        KASSERT((m->oflags & VPO_UNMANAGED) == 0,
            ("pmap_clear_modify: page %p is not managed", m));
        VM_OBJECT_ASSERT_WLOCKED(m->object);
        KASSERT(!vm_page_xbusied(m),
            ("pmap_clear_modify: page %p is exclusive busied", m));

        /*
         * If the page is not PGA_WRITEABLE, then no PTEs can be modified.
         * If the object containing the page is locked and the page is not
         * exclusive busied, then PGA_WRITEABLE cannot be concurrently set.
         */
        if ((m->aflags & PGA_WRITEABLE) == 0)
                return;
        rw_wlock(&pvh_global_lock);
        TAILQ_FOREACH(pv, &m->md.pv_list, pv_list) {
                pmap = PV_PMAP(pv);
                PMAP_LOCK(pmap);
                oldpmap = pmap_switch(pmap);
                pte = pmap_find_vhpt(pv->pv_va);
                KASSERT(pte != NULL, ("pte"));
                if (pmap_dirty(pte)) {
                        pmap_clear_dirty(pte);
                        pmap_invalidate_page(pv->pv_va);
                }
                pmap_switch(oldpmap);
                PMAP_UNLOCK(pmap);
        }
        rw_wunlock(&pvh_global_lock);
}

/*
 * Clear the write and modified bits in each of the given page's mappings.
 */
void
pmap_remove_write(vm_page_t m)
{
        struct ia64_lpte *pte;
        pmap_t oldpmap, pmap;
        pv_entry_t pv;
        vm_prot_t prot;

        KASSERT((m->oflags & VPO_UNMANAGED) == 0,
            ("pmap_remove_write: page %p is not managed", m));

        /*
         * If the page is not exclusive busied, then PGA_WRITEABLE cannot be
         * set by another thread while the object is locked.  Thus,
         * if PGA_WRITEABLE is clear, no page table entries need updating.
         */
        VM_OBJECT_ASSERT_WLOCKED(m->object);
        if (!vm_page_xbusied(m) && (m->aflags & PGA_WRITEABLE) == 0)
                return;
        rw_wlock(&pvh_global_lock);
        TAILQ_FOREACH(pv, &m->md.pv_list, pv_list) {
                pmap = PV_PMAP(pv);
                PMAP_LOCK(pmap);
                oldpmap = pmap_switch(pmap);
                pte = pmap_find_vhpt(pv->pv_va);
                KASSERT(pte != NULL, ("pte"));
                prot = pmap_prot(pte);
                if ((prot & VM_PROT_WRITE) != 0) {
                        if (pmap_dirty(pte)) {
                                vm_page_dirty(m);
                                pmap_clear_dirty(pte);
                        }
                        prot &= ~VM_PROT_WRITE;
                        pmap_pte_prot(pmap, pte, prot);
                        pmap_pte_attr(pte, m->md.memattr);
                        pmap_invalidate_page(pv->pv_va);
                }
                pmap_switch(oldpmap);
                PMAP_UNLOCK(pmap);
        }
        vm_page_aflag_clear(m, PGA_WRITEABLE);
        rw_wunlock(&pvh_global_lock);
}

/*
 * Map a set of physical memory pages into the kernel virtual
 * address space. Return a pointer to where it is mapped. This
 * routine is intended to be used for mapping device memory,
 * NOT real memory.
 */
void *
pmap_mapdev(vm_paddr_t pa, vm_size_t sz)
{
        static void *last_va = NULL;
        static vm_paddr_t last_pa = 0;
        static vm_size_t last_sz = 0;
        struct efi_md *md;
        vm_offset_t va;

        if (pa == last_pa && sz == last_sz)
                return (last_va);

        md = efi_md_find(pa);
        if (md == NULL) {
                printf("%s: [%#lx..%#lx] not covered by memory descriptor\n",
                    __func__, pa, pa + sz - 1);
                return ((void *)IA64_PHYS_TO_RR6(pa));
        }

        if (md->md_type == EFI_MD_TYPE_FREE) {
                printf("%s: [%#lx..%#lx] is in DRAM\n", __func__, pa,
                    pa + sz - 1);
                return (NULL);
        }

        va = (md->md_attr & EFI_MD_ATTR_WB) ? IA64_PHYS_TO_RR7(pa) :
            IA64_PHYS_TO_RR6(pa);

        last_va = (void *)va;
        last_pa = pa;
        last_sz = sz;
        return (last_va);
}

/*
 * 'Unmap' a range mapped by pmap_mapdev().
 */
void
pmap_unmapdev(vm_offset_t va, vm_size_t size)
{
}

/*
 * Sets the memory attribute for the specified page.
 */
static void
pmap_page_set_memattr_1(void *arg)
{
        struct ia64_pal_result res;
        register_t is;
        uintptr_t pp = (uintptr_t)arg;

        is = intr_disable();
        res = ia64_call_pal_static(pp, 0, 0, 0);
        intr_restore(is);
}

void
pmap_page_set_memattr(vm_page_t m, vm_memattr_t ma)
{
        struct ia64_lpte *pte;
        pmap_t oldpmap, pmap;
        pv_entry_t pv;
        void *va;

        rw_wlock(&pvh_global_lock);
        m->md.memattr = ma;
        TAILQ_FOREACH(pv, &m->md.pv_list, pv_list) {
                pmap = PV_PMAP(pv);
                PMAP_LOCK(pmap);
                oldpmap = pmap_switch(pmap);
                pte = pmap_find_vhpt(pv->pv_va);
                KASSERT(pte != NULL, ("pte"));
                pmap_pte_attr(pte, ma);
                pmap_invalidate_page(pv->pv_va);
                pmap_switch(oldpmap);
                PMAP_UNLOCK(pmap);
        }
        rw_wunlock(&pvh_global_lock);

        if (ma == VM_MEMATTR_UNCACHEABLE) {
#ifdef SMP
                smp_rendezvous(NULL, pmap_page_set_memattr_1, NULL,
                    (void *)PAL_PREFETCH_VISIBILITY);
#else
                pmap_page_set_memattr_1((void *)PAL_PREFETCH_VISIBILITY);
#endif
                va = (void *)pmap_page_to_va(m);
                critical_enter();
                cpu_flush_dcache(va, PAGE_SIZE);
                critical_exit();
#ifdef SMP
                smp_rendezvous(NULL, pmap_page_set_memattr_1, NULL,
                    (void *)PAL_MC_DRAIN);
#else
                pmap_page_set_memattr_1((void *)PAL_MC_DRAIN);
#endif
        }
}

/*
 * perform the pmap work for mincore
 */
int
pmap_mincore(pmap_t pmap, vm_offset_t addr, vm_paddr_t *locked_pa)
{
        pmap_t oldpmap;
        struct ia64_lpte *pte, tpte;
        vm_paddr_t pa;
        int val;

        PMAP_LOCK(pmap);
retry:
        oldpmap = pmap_switch(pmap);
        pte = pmap_find_vhpt(addr);
        if (pte != NULL) {
                tpte = *pte;
                pte = &tpte;
        }
        pmap_switch(oldpmap);
        if (pte == NULL || !pmap_present(pte)) {
                val = 0;
                goto out;
        }
        val = MINCORE_INCORE;
        if (pmap_dirty(pte))
                val |= MINCORE_MODIFIED | MINCORE_MODIFIED_OTHER;
        if (pmap_accessed(pte))
                val |= MINCORE_REFERENCED | MINCORE_REFERENCED_OTHER;
        if ((val & (MINCORE_MODIFIED_OTHER | MINCORE_REFERENCED_OTHER)) !=
            (MINCORE_MODIFIED_OTHER | MINCORE_REFERENCED_OTHER) &&
            pmap_managed(pte)) {
                pa = pmap_ppn(pte);
                /* Ensure that "PHYS_TO_VM_PAGE(pa)->object" doesn't change. */
                if (vm_page_pa_tryrelock(pmap, pa, locked_pa))
                        goto retry;
        } else
out:
                PA_UNLOCK_COND(*locked_pa);
        PMAP_UNLOCK(pmap);
        return (val);
}

void
pmap_activate(struct thread *td)
{
        pmap_switch(vmspace_pmap(td->td_proc->p_vmspace));
}

pmap_t
pmap_switch(pmap_t pm)
{
        pmap_t prevpm;
        int i;

        critical_enter();
        prevpm = PCPU_GET(md.current_pmap);
        if (prevpm == pm)
                goto out;
        if (pm == NULL) {
                for (i = 0; i < IA64_VM_MINKERN_REGION; i++) {
                        ia64_set_rr(IA64_RR_BASE(i),
                            (i << 8)|(PAGE_SHIFT << 2)|1);
                }
        } else {
                for (i = 0; i < IA64_VM_MINKERN_REGION; i++) {
                        ia64_set_rr(IA64_RR_BASE(i),
                            (pm->pm_rid[i] << 8)|(PAGE_SHIFT << 2)|1);
                }
        }
        PCPU_SET(md.current_pmap, pm);
        ia64_srlz_d();

out:
        critical_exit();
        return (prevpm);
}

void
pmap_sync_icache(pmap_t pm, vm_offset_t va, vm_size_t sz)
{
        pmap_t oldpm;
        struct ia64_lpte *pte;
        vm_offset_t lim;
        vm_size_t len;

        sz += va & 31;
        va &= ~31;
        sz = (sz + 31) & ~31;

        PMAP_LOCK(pm);
        oldpm = pmap_switch(pm);
        while (sz > 0) {
                lim = round_page(va);
                len = MIN(lim - va, sz);
                pte = pmap_find_vhpt(va);
                if (pte != NULL && pmap_present(pte))
                        ia64_sync_icache(va, len);
                va += len;
                sz -= len;
        }
        pmap_switch(oldpm);
        PMAP_UNLOCK(pm);
}

/*
 *      Increase the starting virtual address of the given mapping if a
 *      different alignment might result in more superpage mappings.
 */
void
pmap_align_superpage(vm_object_t object, vm_ooffset_t offset,
    vm_offset_t *addr, vm_size_t size)
{
}

#include "opt_ddb.h"

#ifdef DDB

#include <ddb/ddb.h>

static const char*      psnames[] = {
        "1B",   "2B",   "4B",   "8B",
        "16B",  "32B",  "64B",  "128B",
        "256B", "512B", "1K",   "2K",
        "4K",   "8K",   "16K",  "32K",
        "64K",  "128K", "256K", "512K",
        "1M",   "2M",   "4M",   "8M",
        "16M",  "32M",  "64M",  "128M",
        "256M", "512M", "1G",   "2G"
};

static void
print_trs(int type)
{
        struct ia64_pal_result res;
        int i, maxtr;
        struct {
                pt_entry_t      pte;
                uint64_t        itir;
                uint64_t        ifa;
                struct ia64_rr  rr;
        } buf;
        static const char *manames[] = {
                "WB",   "bad",  "bad",  "bad",
                "UC",   "UCE",  "WC",   "NaT",
        };

        res = ia64_call_pal_static(PAL_VM_SUMMARY, 0, 0, 0);
        if (res.pal_status != 0) {
                db_printf("Can't get VM summary\n");
                return;
        }

        if (type == 0)
                maxtr = (res.pal_result[0] >> 40) & 0xff;
        else
                maxtr = (res.pal_result[0] >> 32) & 0xff;

        db_printf("V RID    Virtual Page  Physical Page PgSz ED AR PL D A MA  P KEY\n");
        for (i = 0; i <= maxtr; i++) {
                bzero(&buf, sizeof(buf));
                res = ia64_pal_physical(PAL_VM_TR_READ, i, type,
                    ia64_tpa((uint64_t)&buf));
                if (!(res.pal_result[0] & 1))
                        buf.pte &= ~PTE_AR_MASK;
                if (!(res.pal_result[0] & 2))
                        buf.pte &= ~PTE_PL_MASK;
                if (!(res.pal_result[0] & 4))
                        pmap_clear_dirty(&buf);
                if (!(res.pal_result[0] & 8))
                        buf.pte &= ~PTE_MA_MASK;
                db_printf("%d %06x %013lx %013lx %4s %d  %d  %d  %d %d %-3s "
                    "%d %06x\n", (int)buf.ifa & 1, buf.rr.rr_rid,
                    buf.ifa >> 12, (buf.pte & PTE_PPN_MASK) >> 12,
                    psnames[(buf.itir & ITIR_PS_MASK) >> 2],
                    (buf.pte & PTE_ED) ? 1 : 0,
                    (int)(buf.pte & PTE_AR_MASK) >> 9,
                    (int)(buf.pte & PTE_PL_MASK) >> 7,
                    (pmap_dirty(&buf)) ? 1 : 0,
                    (pmap_accessed(&buf)) ? 1 : 0,
                    manames[(buf.pte & PTE_MA_MASK) >> 2],
                    (pmap_present(&buf)) ? 1 : 0,
                    (int)((buf.itir & ITIR_KEY_MASK) >> 8));
        }
}

DB_COMMAND(itr, db_itr)
{
        print_trs(0);
}

DB_COMMAND(dtr, db_dtr)
{
        print_trs(1);
}

DB_COMMAND(rr, db_rr)
{
        int i;
        uint64_t t;
        struct ia64_rr rr;

        printf("RR RID    PgSz VE\n");
        for (i = 0; i < 8; i++) {
                __asm __volatile ("mov %0=rr[%1]"
                                  : "=r"(t)
                                  : "r"(IA64_RR_BASE(i)));
                *(uint64_t *) &rr = t;
                printf("%d  %06x %4s %d\n",
                       i, rr.rr_rid, psnames[rr.rr_ps], rr.rr_ve);
        }
}

DB_COMMAND(thash, db_thash)
{
        if (!have_addr)
                return;

        db_printf("%p\n", (void *) ia64_thash(addr));
}

DB_COMMAND(ttag, db_ttag)
{
        if (!have_addr)
                return;

        db_printf("0x%lx\n", ia64_ttag(addr));
}

DB_COMMAND(kpte, db_kpte)
{
        struct ia64_lpte *pte;

        if (!have_addr) {
                db_printf("usage: kpte <kva>\n");
                return;
        }
        if (addr < VM_INIT_KERNEL_ADDRESS) {
                db_printf("kpte: error: invalid <kva>\n");
                return;
        }
        pte = pmap_find_kpte(addr);
        db_printf("kpte at %p:\n", pte);
        db_printf("  pte  =%016lx\n", pte->pte);
        db_printf("  itir =%016lx\n", pte->itir);
        db_printf("  tag  =%016lx\n", pte->tag);
        db_printf("  chain=%016lx\n", pte->chain);
}

#endif