xnu-344.23.tar.gz

[apple/xnu.git] / osfmk / i386 / pmap.c

/*
 * Copyright (c) 2000 Apple Computer, Inc. All rights reserved.
 *
 * @APPLE_LICENSE_HEADER_START@
 * 
 * The contents of this file constitute Original Code as defined in and
 * are subject to the Apple Public Source License Version 1.1 (the
 * "License").  You may not use this file except in compliance with the
 * License.  Please obtain a copy of the License at
 * http://www.apple.com/publicsource and read it before using this file.
 * 
 * This Original Code and all software distributed under the License are
 * distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, EITHER
 * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
 * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT.  Please see the
 * License for the specific language governing rights and limitations
 * under the License.
 * 
 * @APPLE_LICENSE_HEADER_END@
 */
/*
 * @OSF_COPYRIGHT@
 */
/*
 * Mach Operating System
 * Copyright (c) 1991,1990,1989,1988 Carnegie Mellon University
 * All Rights Reserved.
 * 
 * Permission to use, copy, modify and distribute this software and its
 * documentation is hereby granted, provided that both the copyright
 * notice and this permission notice appear in all copies of the
 * software, derivative works or modified versions, and any portions
 * thereof, and that both notices appear in supporting documentation.
 * 
 * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
 * CONDITION.  CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND FOR
 * ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
 * 
 * Carnegie Mellon requests users of this software to return to
 * 
 *  Software Distribution Coordinator  or  Software.Distribution@CS.CMU.EDU
 *  School of Computer Science
 *  Carnegie Mellon University
 *  Pittsburgh PA 15213-3890
 * 
 * any improvements or extensions that they make and grant Carnegie Mellon
 * the rights to redistribute these changes.
 */
/*
 */

/*
 *      File:   pmap.c
 *      Author: Avadis Tevanian, Jr., Michael Wayne Young
 *      (These guys wrote the Vax version)
 *
 *      Physical Map management code for Intel i386, i486, and i860.
 *
 *      Manages physical address maps.
 *
 *      In addition to hardware address maps, this
 *      module is called upon to provide software-use-only
 *      maps which may or may not be stored in the same
 *      form as hardware maps.  These pseudo-maps are
 *      used to store intermediate results from copy
 *      operations to and from address spaces.
 *
 *      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.
 */

#include <cpus.h>

#include <string.h>
#include <norma_vm.h>
#include <mach_kdb.h>
#include <mach_ldebug.h>

#include <mach/machine/vm_types.h>

#include <mach/boolean.h>
#include <kern/thread.h>
#include <kern/zalloc.h>

#include <kern/lock.h>
#include <kern/spl.h>

#include <vm/pmap.h>
#include <vm/vm_map.h>
#include <vm/vm_kern.h>
#include <mach/vm_param.h>
#include <mach/vm_prot.h>
#include <vm/vm_object.h>
#include <vm/vm_page.h>

#include <mach/machine/vm_param.h>
#include <machine/thread.h>

#include <kern/misc_protos.h>                   /* prototyping */
#include <i386/misc_protos.h>

#include <i386/cpuid.h>

#if     MACH_KDB
#include <ddb/db_command.h>
#include <ddb/db_output.h>
#include <ddb/db_sym.h>
#include <ddb/db_print.h>
#endif  /* MACH_KDB */

#include <kern/xpr.h>

#if NCPUS > 1
#include <i386/AT386/mp/mp_events.h>
#endif

/*
 * Forward declarations for internal functions.
 */
void    pmap_expand(
                        pmap_t          map,
                        vm_offset_t     v);

extern void     pmap_remove_range(
                        pmap_t          pmap,
                        vm_offset_t     va,
                        pt_entry_t      *spte,
                        pt_entry_t      *epte);

void    phys_attribute_clear(
                        vm_offset_t     phys,
                        int             bits);

boolean_t phys_attribute_test(
                        vm_offset_t     phys,
                        int             bits);

void pmap_set_modify(vm_offset_t        phys);

void phys_attribute_set(
                        vm_offset_t     phys,
                        int             bits);


#ifndef set_dirbase
void    set_dirbase(vm_offset_t dirbase);
#endif  /* set_dirbase */

#define PA_TO_PTE(pa)   (pa_to_pte((pa) - VM_MIN_KERNEL_ADDRESS))
#define iswired(pte)    ((pte) & INTEL_PTE_WIRED)

pmap_t  real_pmap[NCPUS];

#define WRITE_PTE(pte_p, pte_entry)             *(pte_p) = (pte_entry);
#define WRITE_PTE_FAST(pte_p, pte_entry)        *(pte_p) = (pte_entry);

/*
 *      Private data structures.
 */

/*
 *      For each vm_page_t, there is a list of all currently
 *      valid virtual mappings of that page.  An entry is
 *      a pv_entry_t; the list is the pv_table.
 */

typedef struct pv_entry {
        struct pv_entry *next;          /* next pv_entry */
        pmap_t          pmap;           /* pmap where mapping lies */
        vm_offset_t     va;             /* virtual address for mapping */
} *pv_entry_t;

#define PV_ENTRY_NULL   ((pv_entry_t) 0)

pv_entry_t      pv_head_table;          /* array of entries, one per page */

/*
 *      pv_list entries are kept on a list that can only be accessed
 *      with the pmap system locked (at SPLVM, not in the cpus_active set).
 *      The list is refilled from the pv_list_zone if it becomes empty.
 */
pv_entry_t      pv_free_list;           /* free list at SPLVM */
decl_simple_lock_data(,pv_free_list_lock)

#define PV_ALLOC(pv_e) { \
        simple_lock(&pv_free_list_lock); \
        if ((pv_e = pv_free_list) != 0) { \
            pv_free_list = pv_e->next; \
        } \
        simple_unlock(&pv_free_list_lock); \
}

#define PV_FREE(pv_e) { \
        simple_lock(&pv_free_list_lock); \
        pv_e->next = pv_free_list; \
        pv_free_list = pv_e; \
        simple_unlock(&pv_free_list_lock); \
}

zone_t          pv_list_zone;           /* zone of pv_entry structures */

/*
 *      Each entry in the pv_head_table is locked by a bit in the
 *      pv_lock_table.  The lock bits are accessed by the physical
 *      address of the page they lock.
 */

char    *pv_lock_table;         /* pointer to array of bits */
#define pv_lock_table_size(n)   (((n)+BYTE_SIZE-1)/BYTE_SIZE)

/*
 *      First and last physical addresses that we maintain any information
 *      for.  Initialized to zero so that pmap operations done before
 *      pmap_init won't touch any non-existent structures.
 */
vm_offset_t     vm_first_phys = (vm_offset_t) 0;
vm_offset_t     vm_last_phys  = (vm_offset_t) 0;
boolean_t       pmap_initialized = FALSE;/* Has pmap_init completed? */

/*
 *      Index into pv_head table, its lock bits, and the modify/reference
 *      bits starting at vm_first_phys.
 */

#define pa_index(pa)    (atop(pa - vm_first_phys))

#define pai_to_pvh(pai)         (&pv_head_table[pai])
#define lock_pvh_pai(pai)       bit_lock(pai, (void *)pv_lock_table)
#define unlock_pvh_pai(pai)     bit_unlock(pai, (void *)pv_lock_table)

/*
 *      Array of physical page attribites for managed pages.
 *      One byte per physical page.
 */
char    *pmap_phys_attributes;

/*
 *      Physical page attributes.  Copy bits from PTE definition.
 */
#define PHYS_MODIFIED   INTEL_PTE_MOD   /* page modified */
#define PHYS_REFERENCED INTEL_PTE_REF   /* page referenced */

/*
 *      Amount of virtual memory mapped by one
 *      page-directory entry.
 */
#define PDE_MAPPED_SIZE         (pdetova(1))

/*
 *      We allocate page table pages directly from the VM system
 *      through this object.  It maps physical memory.
 */
vm_object_t     pmap_object = VM_OBJECT_NULL;

/*
 *      Locking and TLB invalidation
 */

/*
 *      Locking Protocols:
 *
 *      There are two structures in the pmap module that need locking:
 *      the pmaps themselves, and the per-page pv_lists (which are locked
 *      by locking the pv_lock_table entry that corresponds to the pv_head
 *      for the list in question.)  Most routines want to lock a pmap and
 *      then do operations in it that require pv_list locking -- however
 *      pmap_remove_all and pmap_copy_on_write operate on a physical page
 *      basis and want to do the locking in the reverse order, i.e. lock
 *      a pv_list and then go through all the pmaps referenced by that list.
 *      To protect against deadlock between these two cases, the pmap_lock
 *      is used.  There are three different locking protocols as a result:
 *
 *  1.  pmap operations only (pmap_extract, pmap_access, ...)  Lock only
 *              the pmap.
 *
 *  2.  pmap-based operations (pmap_enter, pmap_remove, ...)  Get a read
 *              lock on the pmap_lock (shared read), then lock the pmap
 *              and finally the pv_lists as needed [i.e. pmap lock before
 *              pv_list lock.]
 *
 *  3.  pv_list-based operations (pmap_remove_all, pmap_copy_on_write, ...)
 *              Get a write lock on the pmap_lock (exclusive write); this
 *              also guaranteees exclusive access to the pv_lists.  Lock the
 *              pmaps as needed.
 *
 *      At no time may any routine hold more than one pmap lock or more than
 *      one pv_list lock.  Because interrupt level routines can allocate
 *      mbufs and cause pmap_enter's, the pmap_lock and the lock on the
 *      kernel_pmap can only be held at splhigh.
 */

#if     NCPUS > 1
/*
 *      We raise the interrupt level to splhigh, to block interprocessor
 *      interrupts during pmap operations.  We must take the CPU out of
 *      the cpus_active set while interrupts are blocked.
 */
#define SPLVM(spl)      { \
        spl = splhigh(); \
        mp_disable_preemption(); \
        i_bit_clear(cpu_number(), &cpus_active); \
        mp_enable_preemption(); \
}

#define SPLX(spl)       { \
        mp_disable_preemption(); \
        i_bit_set(cpu_number(), &cpus_active); \
        mp_enable_preemption(); \
        splx(spl); \
}

/*
 *      Lock on pmap system
 */
lock_t  pmap_system_lock;

#define PMAP_READ_LOCK(pmap, spl) {     \
        SPLVM(spl);                     \
        lock_read(&pmap_system_lock);   \
        simple_lock(&(pmap)->lock);     \
}

#define PMAP_WRITE_LOCK(spl) {          \
        SPLVM(spl);                     \
        lock_write(&pmap_system_lock);  \
}

#define PMAP_READ_UNLOCK(pmap, spl) {           \
        simple_unlock(&(pmap)->lock);           \
        lock_read_done(&pmap_system_lock);      \
        SPLX(spl);                              \
}

#define PMAP_WRITE_UNLOCK(spl) {                \
        lock_write_done(&pmap_system_lock);     \
        SPLX(spl);                              \
}

#define PMAP_WRITE_TO_READ_LOCK(pmap) {         \
        simple_lock(&(pmap)->lock);             \
        lock_write_to_read(&pmap_system_lock);  \
}

#define LOCK_PVH(index)         lock_pvh_pai(index)

#define UNLOCK_PVH(index)       unlock_pvh_pai(index)

#define PMAP_FLUSH_TLBS()                                               \
{                                                                       \
        flush_tlb();                                                    \
        i386_signal_cpus(MP_TLB_FLUSH);                                 \
}

#define PMAP_RELOAD_TLBS()      {               \
        i386_signal_cpus(MP_TLB_RELOAD);        \
        set_cr3(kernel_pmap->pdirbase);         \
}

#define PMAP_INVALIDATE_PAGE(map, addr) {       \
        if (map == kernel_pmap)                 \
                invlpg((vm_offset_t) addr);     \
        else                                    \
                flush_tlb();                    \
        i386_signal_cpus(MP_TLB_FLUSH);         \
}

#else   /* NCPUS > 1 */

#if     MACH_RT
#define SPLVM(spl)                      { (spl) = splhigh(); }
#define SPLX(spl)                       splx (spl)
#else   /* MACH_RT */
#define SPLVM(spl)
#define SPLX(spl)
#endif  /* MACH_RT */

#define PMAP_READ_LOCK(pmap, spl)       SPLVM(spl)
#define PMAP_WRITE_LOCK(spl)            SPLVM(spl)
#define PMAP_READ_UNLOCK(pmap, spl)     SPLX(spl)
#define PMAP_WRITE_UNLOCK(spl)          SPLX(spl)
#define PMAP_WRITE_TO_READ_LOCK(pmap)

#if     MACH_RT
#define LOCK_PVH(index)                 disable_preemption()
#define UNLOCK_PVH(index)               enable_preemption()
#else   /* MACH_RT */
#define LOCK_PVH(index)
#define UNLOCK_PVH(index)
#endif  /* MACH_RT */

#define PMAP_FLUSH_TLBS()       flush_tlb()
#define PMAP_RELOAD_TLBS()      set_cr3(kernel_pmap->pdirbase)
#define PMAP_INVALIDATE_PAGE(map, addr) {       \
                if (map == kernel_pmap)         \
                        invlpg((vm_offset_t) addr);     \
                else                            \
                        flush_tlb();            \
}

#endif  /* NCPUS > 1 */

#define MAX_TBIS_SIZE   32              /* > this -> TBIA */ /* XXX */

#if     NCPUS > 1
/*
 *      Structures to keep track of pending TLB invalidations
 */
cpu_set                 cpus_active;
cpu_set                 cpus_idle;
volatile boolean_t      cpu_update_needed[NCPUS];


#endif  /* NCPUS > 1 */

/*
 *      Other useful macros.
 */
#define current_pmap()          (vm_map_pmap(current_act()->map))
#define pmap_in_use(pmap, cpu)  (((pmap)->cpus_using & (1 << (cpu))) != 0)

struct pmap     kernel_pmap_store;
pmap_t          kernel_pmap;

struct zone     *pmap_zone;             /* zone of pmap structures */

int             pmap_debug = 0;         /* flag for debugging prints */
int             ptes_per_vm_page;       /* number of hardware ptes needed
                                           to map one VM page. */
unsigned int    inuse_ptepages_count = 0;       /* debugging */

/*
 *      Pmap cache.  Cache is threaded through ref_count field of pmap.
 *      Max will eventually be constant -- variable for experimentation.
 */
int             pmap_cache_max = 32;
int             pmap_alloc_chunk = 8;
pmap_t          pmap_cache_list;
int             pmap_cache_count;
decl_simple_lock_data(,pmap_cache_lock)

extern  vm_offset_t     hole_start, hole_end;

extern char end;

/*
 * Page directory for kernel.
 */
pt_entry_t      *kpde = 0;      /* set by start.s - keep out of bss */

#if  DEBUG_ALIAS
#define PMAP_ALIAS_MAX 32
struct pmap_alias {
        vm_offset_t rpc;
        pmap_t pmap;
        vm_offset_t va;
        int cookie;
#define PMAP_ALIAS_COOKIE 0xdeadbeef
} pmap_aliasbuf[PMAP_ALIAS_MAX];
int pmap_alias_index = 0;
extern vm_offset_t get_rpc();

#endif  /* DEBUG_ALIAS */

/*
 *      Given an offset and a map, compute the address of the
 *      pte.  If the address is invalid with respect to the map
 *      then PT_ENTRY_NULL is returned (and the map may need to grow).
 *
 *      This is only used in machine-dependent code.
 */

pt_entry_t *
pmap_pte(
        register pmap_t         pmap,
        register vm_offset_t    addr)
{
        register pt_entry_t     *ptp;
        register pt_entry_t     pte;

        pte = pmap->dirbase[pdenum(pmap, addr)];
        if ((pte & INTEL_PTE_VALID) == 0)
                return(PT_ENTRY_NULL);
        ptp = (pt_entry_t *)ptetokv(pte);
        return(&ptp[ptenum(addr)]);

}

#define pmap_pde(pmap, addr) (&(pmap)->dirbase[pdenum(pmap, addr)])

#define DEBUG_PTE_PAGE  0

#if     DEBUG_PTE_PAGE
void
ptep_check(
        ptep_t  ptep)
{
        register pt_entry_t     *pte, *epte;
        int                     ctu, ctw;

        /* check the use and wired counts */
        if (ptep == PTE_PAGE_NULL)
                return;
        pte = pmap_pte(ptep->pmap, ptep->va);
        epte = pte + INTEL_PGBYTES/sizeof(pt_entry_t);
        ctu = 0;
        ctw = 0;
        while (pte < epte) {
                if (pte->pfn != 0) {
                        ctu++;
                        if (pte->wired)
                                ctw++;
                }
                pte += ptes_per_vm_page;
        }

        if (ctu != ptep->use_count || ctw != ptep->wired_count) {
                printf("use %d wired %d - actual use %d wired %d\n",
                        ptep->use_count, ptep->wired_count, ctu, ctw);
                panic("pte count");
        }
}
#endif  /* DEBUG_PTE_PAGE */

/*
 *      Map memory at initialization.  The physical addresses being
 *      mapped are not managed and are never unmapped.
 *
 *      For now, VM is already on, we only need to map the
 *      specified memory.
 */
vm_offset_t
pmap_map(
        register vm_offset_t    virt,
        register vm_offset_t    start,
        register vm_offset_t    end,
        register vm_prot_t      prot)
{
        register int            ps;

        ps = PAGE_SIZE;
        while (start < end) {
                pmap_enter(kernel_pmap, virt, start, prot, 0, FALSE);
                virt += ps;
                start += ps;
        }
        return(virt);
}

/*
 *      Back-door routine for mapping kernel VM at initialization.  
 *      Useful for mapping memory outside the range
 *      Sets no-cache, A, D.
 *      [vm_first_phys, vm_last_phys) (i.e., devices).
 *      Otherwise like pmap_map.
 */
vm_offset_t
pmap_map_bd(
        register vm_offset_t    virt,
        register vm_offset_t    start,
        register vm_offset_t    end,
        vm_prot_t               prot)
{
        register pt_entry_t     template;
        register pt_entry_t     *pte;

        template = pa_to_pte(start)
                | INTEL_PTE_NCACHE
                | INTEL_PTE_REF
                | INTEL_PTE_MOD
                | INTEL_PTE_WIRED
                | INTEL_PTE_VALID;
        if (prot & VM_PROT_WRITE)
            template |= INTEL_PTE_WRITE;

        while (start < end) {
                pte = pmap_pte(kernel_pmap, virt);
                if (pte == PT_ENTRY_NULL)
                        panic("pmap_map_bd: Invalid kernel address\n");
                WRITE_PTE_FAST(pte, template)
                pte_increment_pa(template);
                virt += PAGE_SIZE;
                start += PAGE_SIZE;
        }

        PMAP_FLUSH_TLBS();

        return(virt);
}

extern int              cnvmem;
extern  char            *first_avail;
extern  vm_offset_t     virtual_avail, virtual_end;
extern  vm_offset_t     avail_start, avail_end, avail_next;

/*
 *      Bootstrap the system enough to run with virtual memory.
 *      Map the kernel's code and data, and allocate the system page table.
 *      Called with mapping OFF.  Page_size must already be set.
 *
 *      Parameters:
 *      load_start:     PA where kernel was loaded
 *      avail_start     PA of first available physical page -
 *                         after kernel page tables
 *      avail_end       PA of last available physical page
 *      virtual_avail   VA of first available page -
 *                         after kernel page tables
 *      virtual_end     VA of last available page -
 *                         end of kernel address space
 *
 *      &start_text     start of kernel text
 *      &etext          end of kernel text
 */

void
pmap_bootstrap(
        vm_offset_t     load_start)
{
        vm_offset_t     va, tva, paddr;
        pt_entry_t      template;
        pt_entry_t      *pde, *pte, *ptend;
        vm_size_t       morevm;         /* VM space for kernel map */

        /*
         *      Set ptes_per_vm_page for general use.
         */
        ptes_per_vm_page = PAGE_SIZE / INTEL_PGBYTES;

        /*
         *      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.
         */

        kernel_pmap = &kernel_pmap_store;

#if     NCPUS > 1
        lock_init(&pmap_system_lock,
                  FALSE,                /* NOT a sleep lock */
                  ETAP_VM_PMAP_SYS,
                  ETAP_VM_PMAP_SYS_I);
#endif  /* NCPUS > 1 */

        simple_lock_init(&kernel_pmap->lock, ETAP_VM_PMAP_KERNEL);
        simple_lock_init(&pv_free_list_lock, ETAP_VM_PMAP_FREE);

        kernel_pmap->ref_count = 1;

        /*
         *      The kernel page directory has been allocated;
         *      its virtual address is in kpde.
         *
         *      Enough kernel page table pages have been allocated
         *      to map low system memory, kernel text, kernel data/bss,
         *      kdb's symbols, and the page directory and page tables.
         *
         *      No other physical memory has been allocated.
         */

        /*
         * Start mapping virtual memory to physical memory, 1-1,
         * at end of mapped memory.
         */

        virtual_avail = phystokv(avail_start);
        virtual_end = phystokv(avail_end);

        pde = kpde;
        pde += pdenum(kernel_pmap, virtual_avail);

        if (pte_to_pa(*pde) == 0) {
            /* This pte has not been allocated */
            pte = 0; ptend = 0;
        }
        else {
            pte = (pt_entry_t *)ptetokv(*pde);
                                                /* first pte of page */
            ptend = pte+NPTES;                  /* last pte of page */
            pte += ptenum(virtual_avail);       /* point to pte that
                                                   maps first avail VA */
            pde++;      /* point pde to first empty slot */
        }

        template = pa_to_pte(avail_start)
                | INTEL_PTE_VALID
                | INTEL_PTE_WRITE;

        for (va = virtual_avail; va < virtual_end; va += INTEL_PGBYTES) {
            if (pte >= ptend) {
                pte = (pt_entry_t *)phystokv(virtual_avail);
                ptend = pte + NPTES;
                virtual_avail = (vm_offset_t)ptend;
                if (virtual_avail == hole_start)
                  virtual_avail = hole_end;
                *pde = PA_TO_PTE((vm_offset_t) pte)
                        | INTEL_PTE_VALID
                        | INTEL_PTE_WRITE;
                pde++;
            }
            WRITE_PTE_FAST(pte, template)
            pte++;
            pte_increment_pa(template);
        }

        avail_start = virtual_avail - VM_MIN_KERNEL_ADDRESS;
        avail_next = avail_start;

        /*
         *      Figure out maximum kernel address.
         *      Kernel virtual space is:
         *              - at least three times physical memory
         *              - at least VM_MIN_KERNEL_ADDRESS
         *              - limited by VM_MAX_KERNEL_ADDRESS
         */

        morevm = 3*avail_end;
        if (virtual_end + morevm > VM_MAX_KERNEL_ADDRESS)
          morevm = VM_MAX_KERNEL_ADDRESS - virtual_end + 1;

/*
 *      startup requires additional virtual memory (for tables, buffers, 
 *      etc.).  The kd driver may also require some of that memory to
 *      access the graphics board.
 *
 */
        *(int *)&template = 0;

        /*
         * Leave room for kernel-loaded servers, which have been linked at
         * addresses from VM_MIN_KERNEL_LOADED_ADDRESS to
         * VM_MAX_KERNEL_LOADED_ADDRESS.
         */
        if (virtual_end + morevm < VM_MAX_KERNEL_LOADED_ADDRESS + 1)
                morevm = VM_MAX_KERNEL_LOADED_ADDRESS + 1 - virtual_end;


        virtual_end += morevm;
        for (tva = va; tva < virtual_end; tva += INTEL_PGBYTES) {
            if (pte >= ptend) {
                pmap_next_page(&paddr);
                pte = (pt_entry_t *)phystokv(paddr);
                ptend = pte + NPTES;
                *pde = PA_TO_PTE((vm_offset_t) pte)
                        | INTEL_PTE_VALID
                        | INTEL_PTE_WRITE;
                pde++;
            }
            WRITE_PTE_FAST(pte, template)
            pte++;
        }

        virtual_avail = va;

        /* Push the virtual avail address above hole_end */
        if (virtual_avail < hole_end)
                virtual_avail = hole_end;

        /*
         *      c.f. comment above
         *
         */
        virtual_end = va + morevm;
        while (pte < ptend)
            *pte++ = 0;

        /*
         *      invalidate user virtual addresses 
         */
        memset((char *)kpde,
               0,
               pdenum(kernel_pmap,VM_MIN_KERNEL_ADDRESS)*sizeof(pt_entry_t));
        kernel_pmap->dirbase = kpde;
        printf("Kernel virtual space from 0x%x to 0x%x.\n",
                        VM_MIN_KERNEL_ADDRESS, virtual_end);

        avail_start = avail_next;
        printf("Available physical space from 0x%x to 0x%x\n",
                        avail_start, avail_end);

        kernel_pmap->pdirbase = kvtophys((vm_offset_t)kernel_pmap->dirbase);

}

void
pmap_virtual_space(
        vm_offset_t *startp,
        vm_offset_t *endp)
{
        *startp = virtual_avail;
        *endp = virtual_end;
}

/*
 *      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)
{
        register long           npages;
        vm_offset_t             addr;
        register vm_size_t      s;
        int                     i;

        /*
         *      Allocate memory for the pv_head_table and its lock bits,
         *      the modify bit array, and the pte_page table.
         */

        npages = atop(avail_end - avail_start);
        s = (vm_size_t) (sizeof(struct pv_entry) * npages
                                + pv_lock_table_size(npages)
                                + npages);

        s = round_page(s);
        if (kmem_alloc_wired(kernel_map, &addr, s) != KERN_SUCCESS)
                panic("pmap_init");

        memset((char *)addr, 0, s);

        /*
         *      Allocate the structures first to preserve word-alignment.
         */
        pv_head_table = (pv_entry_t) addr;
        addr = (vm_offset_t) (pv_head_table + npages);

        pv_lock_table = (char *) addr;
        addr = (vm_offset_t) (pv_lock_table + pv_lock_table_size(npages));

        pmap_phys_attributes = (char *) addr;

        /*
         *      Create the zone of physical maps,
         *      and of the physical-to-virtual entries.
         */
        s = (vm_size_t) sizeof(struct pmap);
        pmap_zone = zinit(s, 400*s, 4096, "pmap"); /* XXX */
        s = (vm_size_t) sizeof(struct pv_entry);
        pv_list_zone = zinit(s, 10000*s, 4096, "pv_list"); /* XXX */

        /*
         *      Only now, when all of the data structures are allocated,
         *      can we set vm_first_phys and vm_last_phys.  If we set them
         *      too soon, the kmem_alloc_wired above will try to use these
         *      data structures and blow up.
         */

        vm_first_phys = avail_start;
        vm_last_phys = avail_end;
        pmap_initialized = TRUE;

        /*
         *      Initializie pmap cache.
         */
        pmap_cache_list = PMAP_NULL;
        pmap_cache_count = 0;
        simple_lock_init(&pmap_cache_lock, ETAP_VM_PMAP_CACHE);
}


#define pmap_valid_page(x)      ((avail_start <= x) && (x < avail_end))


#define valid_page(x) (pmap_initialized && pmap_valid_page(x))

boolean_t
pmap_verify_free(
        vm_offset_t     phys)
{
        pv_entry_t      pv_h;
        int             pai;
        spl_t           spl;
        boolean_t       result;

        assert(phys != vm_page_fictitious_addr);
        if (!pmap_initialized)
                return(TRUE);

        if (!pmap_valid_page(phys))
                return(FALSE);

        PMAP_WRITE_LOCK(spl);

        pai = pa_index(phys);
        pv_h = pai_to_pvh(pai);

        result = (pv_h->pmap == PMAP_NULL);
        PMAP_WRITE_UNLOCK(spl);

        return(result);
}

/*
 *      Create and return a physical map.
 *
 *      If the size specified for the map
 *      is zero, the map is an actual physical
 *      map, and may be referenced by the
 *      hardware.
 *
 *      If the size specified is non-zero,
 *      the map will be used in software only, and
 *      is bounded by that size.
 */
pmap_t
pmap_create(
        vm_size_t       size)
{
        register pmap_t                 p;
        register pmap_statistics_t      stats;

        /*
         *      A software use-only map doesn't even need a map.
         */

        if (size != 0) {
                return(PMAP_NULL);
        }

        /*
         *      Try to get cached pmap, if this fails,
         *      allocate a pmap struct from the pmap_zone.  Then allocate
         *      the page descriptor table from the pd_zone.
         */

        simple_lock(&pmap_cache_lock);
        while ((p = pmap_cache_list) == PMAP_NULL) {

                vm_offset_t             dirbases;
                register int            i;

                simple_unlock(&pmap_cache_lock);

#if     NCPUS > 1
        /*
         * XXX  NEEDS MP DOING ALLOC logic so that if multiple processors
         * XXX  get here, only one allocates a chunk of pmaps.
         * (for now we'll just let it go - safe but wasteful)
         */
#endif

                /*
                 *      Allocate a chunck of pmaps.  Single kmem_alloc_wired
                 *      operation reduces kernel map fragmentation.
                 */

                if (kmem_alloc_wired(kernel_map, &dirbases,
                                     pmap_alloc_chunk * INTEL_PGBYTES)
                                                        != KERN_SUCCESS)
                        panic("pmap_create.1");

                for (i = pmap_alloc_chunk; i > 0 ; i--) {
                        p = (pmap_t) zalloc(pmap_zone);
                        if (p == PMAP_NULL)
                                panic("pmap_create.2");

                        /*
                         *      Initialize pmap.  Don't bother with
                         *      ref count as cache list is threaded
                         *      through it.  It'll be set on cache removal.
                         */
                        p->dirbase = (pt_entry_t *) dirbases;
                        dirbases += INTEL_PGBYTES;
                        memcpy(p->dirbase, kpde, INTEL_PGBYTES);
                        p->pdirbase = kvtophys((vm_offset_t)p->dirbase);

                        simple_lock_init(&p->lock, ETAP_VM_PMAP);
                        p->cpus_using = 0;

                        /*
                         *      Initialize statistics.
                         */
                        stats = &p->stats;
                        stats->resident_count = 0;
                        stats->wired_count = 0;
                        
                        /*
                         *      Insert into cache
                         */
                        simple_lock(&pmap_cache_lock);
                        p->ref_count = (int) pmap_cache_list;
                        pmap_cache_list = p;
                        pmap_cache_count++;
                        simple_unlock(&pmap_cache_lock);
                }
                simple_lock(&pmap_cache_lock);
        }

        assert(p->stats.resident_count == 0);
        assert(p->stats.wired_count == 0);
        p->stats.resident_count = 0;
        p->stats.wired_count = 0;

        pmap_cache_list = (pmap_t) p->ref_count;
        p->ref_count = 1;
        pmap_cache_count--;
        simple_unlock(&pmap_cache_lock);

        return(p);
}

/*
 *      Retire the given physical map from service.
 *      Should only be called if the map contains
 *      no valid mappings.
 */

void
pmap_destroy(
        register pmap_t p)
{
        register pt_entry_t     *pdep;
        register vm_offset_t    pa;
        register int            c;
        spl_t                   s;
        register vm_page_t      m;

        if (p == PMAP_NULL)
                return;

        SPLVM(s);
        simple_lock(&p->lock);
        c = --p->ref_count;
        if (c == 0) {
                register int    my_cpu;

                mp_disable_preemption();
                my_cpu = cpu_number();

                /* 
                 * If some cpu is not using the physical pmap pointer that it
                 * is supposed to be (see set_dirbase), we might be using the
                 * pmap that is being destroyed! Make sure we are
                 * physically on the right pmap:
                 */


                if (real_pmap[my_cpu] == p) {
                        PMAP_CPU_CLR(p, my_cpu);
                        real_pmap[my_cpu] = kernel_pmap;
                        PMAP_RELOAD_TLBS();
                }
                mp_enable_preemption();
        }
        simple_unlock(&p->lock);
        SPLX(s);

        if (c != 0) {
            return;     /* still in use */
        }

        /*
         *      Free the memory maps, then the
         *      pmap structure.
         */
        pdep = p->dirbase;
        while (pdep < &p->dirbase[pdenum(p, LINEAR_KERNEL_ADDRESS)]) {
            if (*pdep & INTEL_PTE_VALID) {
                pa = pte_to_pa(*pdep);
                vm_object_lock(pmap_object);
                m = vm_page_lookup(pmap_object, pa);
                if (m == VM_PAGE_NULL)
                    panic("pmap_destroy: pte page not in object");
                vm_page_lock_queues();
                vm_page_free(m);
                inuse_ptepages_count--;
                vm_object_unlock(pmap_object);
                vm_page_unlock_queues();

                /*
                 *      Clear pdes, this might be headed for the cache.
                 */
                c = ptes_per_vm_page;
                do {
                    *pdep = 0;
                    pdep++;
                } while (--c > 0);
            }
            else {
                pdep += ptes_per_vm_page;
            }
        
        }
        assert(p->stats.resident_count == 0);
        assert(p->stats.wired_count == 0);

        /*
         *      Add to cache if not already full
         */
        simple_lock(&pmap_cache_lock);
        if (pmap_cache_count <= pmap_cache_max) {
                p->ref_count = (int) pmap_cache_list;
                pmap_cache_list = p;
                pmap_cache_count++;
                simple_unlock(&pmap_cache_lock);
        }
        else {
                simple_unlock(&pmap_cache_lock);
                kmem_free(kernel_map, (vm_offset_t)p->dirbase, INTEL_PGBYTES);
                zfree(pmap_zone, (vm_offset_t) p);
        }
}

/*
 *      Add a reference to the specified pmap.
 */

void
pmap_reference(
        register pmap_t p)
{
        spl_t   s;

        if (p != PMAP_NULL) {
                SPLVM(s);
                simple_lock(&p->lock);
                p->ref_count++;
                simple_unlock(&p->lock);
                SPLX(s);
        }
}

/*
 *      Remove a range of hardware page-table entries.
 *      The entries given are the first (inclusive)
 *      and last (exclusive) entries for the VM pages.
 *      The virtual address is the va for the first pte.
 *
 *      The pmap must be locked.
 *      If the pmap is not the kernel pmap, the range must lie
 *      entirely within one pte-page.  This is NOT checked.
 *      Assumes that the pte-page exists.
 */

/* static */
void
pmap_remove_range(
        pmap_t                  pmap,
        vm_offset_t             va,
        pt_entry_t              *spte,
        pt_entry_t              *epte)
{
        register pt_entry_t     *cpte;
        int                     num_removed, num_unwired;
        int                     pai;
        vm_offset_t             pa;

#if     DEBUG_PTE_PAGE
        if (pmap != kernel_pmap)
                ptep_check(get_pte_page(spte));
#endif  /* DEBUG_PTE_PAGE */
        num_removed = 0;
        num_unwired = 0;

        for (cpte = spte; cpte < epte;
             cpte += ptes_per_vm_page, va += PAGE_SIZE) {

            pa = pte_to_pa(*cpte);
            if (pa == 0)
                continue;

            num_removed++;
            if (iswired(*cpte))
                num_unwired++;

            if (!valid_page(pa)) {

                /*
                 *      Outside range of managed physical memory.
                 *      Just remove the mappings.
                 */
                register int    i = ptes_per_vm_page;
                register pt_entry_t     *lpte = cpte;
                do {
                    *lpte = 0;
                    lpte++;
                } while (--i > 0);
                continue;
            }

            pai = pa_index(pa);
            LOCK_PVH(pai);

            /*
             *  Get the modify and reference bits.
             */
            {
                register int            i;
                register pt_entry_t     *lpte;

                i = ptes_per_vm_page;
                lpte = cpte;
                do {
                    pmap_phys_attributes[pai] |=
                        *lpte & (PHYS_MODIFIED|PHYS_REFERENCED);
                    *lpte = 0;
                    lpte++;
                } while (--i > 0);
            }

            /*
             *  Remove the mapping from the pvlist for
             *  this physical page.
             */
            {
                register pv_entry_t     pv_h, prev, cur;

                pv_h = pai_to_pvh(pai);
                if (pv_h->pmap == PMAP_NULL) {
                    panic("pmap_remove: null pv_list!");
                }
                if (pv_h->va == va && pv_h->pmap == pmap) {
                    /*
                     * Header is the pv_entry.  Copy the next one
                     * to header and free the next one (we cannot
                     * free the header)
                     */
                    cur = pv_h->next;
                    if (cur != PV_ENTRY_NULL) {
                        *pv_h = *cur;
                        PV_FREE(cur);
                    }
                    else {
                        pv_h->pmap = PMAP_NULL;
                    }
                }
                else {
                    cur = pv_h;
                    do {
                        prev = cur;
                        if ((cur = prev->next) == PV_ENTRY_NULL) {
                            panic("pmap-remove: mapping not in pv_list!");
                        }
                    } while (cur->va != va || cur->pmap != pmap);
                    prev->next = cur->next;
                    PV_FREE(cur);
                }
                UNLOCK_PVH(pai);
            }
        }

        /*
         *      Update the counts
         */
        assert(pmap->stats.resident_count >= num_removed);
        pmap->stats.resident_count -= num_removed;
        assert(pmap->stats.wired_count >= num_unwired);
        pmap->stats.wired_count -= num_unwired;
}

/*
 *      Remove phys addr if mapped in specified map
 *
 */
void
pmap_remove_some_phys(
        pmap_t          map,
        vm_offset_t     phys_addr)
{

/* Implement to support working set code */

}


/*
 *      Remove the given range of addresses
 *      from the specified map.
 *
 *      It is assumed that the start and end are properly
 *      rounded to the hardware page size.
 */

void
pmap_remove(
        pmap_t          map,
        vm_offset_t     s,
        vm_offset_t     e)
{
        spl_t                   spl;
        register pt_entry_t     *pde;
        register pt_entry_t     *spte, *epte;
        vm_offset_t             l;

        if (map == PMAP_NULL)
                return;

        PMAP_READ_LOCK(map, spl);

        pde = pmap_pde(map, s);

        while (s < e) {
            l = (s + PDE_MAPPED_SIZE) & ~(PDE_MAPPED_SIZE-1);
            if (l > e)
                l = e;
            if (*pde & INTEL_PTE_VALID) {
                spte = (pt_entry_t *)ptetokv(*pde);
                spte = &spte[ptenum(s)];
                epte = &spte[intel_btop(l-s)];
                pmap_remove_range(map, s, spte, epte);
            }
            s = l;
            pde++;
        }

        PMAP_FLUSH_TLBS();

        PMAP_READ_UNLOCK(map, spl);
}

/*
 *      Routine:        pmap_page_protect
 *
 *      Function:
 *              Lower the permission for all mappings to a given
 *              page.
 */
void
pmap_page_protect(
        vm_offset_t     phys,
        vm_prot_t       prot)
{
        pv_entry_t              pv_h, prev;
        register pv_entry_t     pv_e;
        register pt_entry_t     *pte;
        int                     pai;
        register pmap_t         pmap;
        spl_t                   spl;
        boolean_t               remove;

        assert(phys != vm_page_fictitious_addr);
        if (!valid_page(phys)) {
            /*
             *  Not a managed page.
             */
            return;
        }

        /*
         * Determine the new protection.
         */
        switch (prot) {
            case VM_PROT_READ:
            case VM_PROT_READ|VM_PROT_EXECUTE:
                remove = FALSE;
                break;
            case VM_PROT_ALL:
                return; /* nothing to do */
            default:
                remove = TRUE;
                break;
        }

        /*
         *      Lock the pmap system first, since we will be changing
         *      several pmaps.
         */

        PMAP_WRITE_LOCK(spl);

        pai = pa_index(phys);
        pv_h = pai_to_pvh(pai);

        /*
         * Walk down PV list, changing or removing all mappings.
         * We do not have to lock the pv_list because we have
         * the entire pmap system locked.
         */
        if (pv_h->pmap != PMAP_NULL) {

            prev = pv_e = pv_h;
            do {
                pmap = pv_e->pmap;
                /*
                 * Lock the pmap to block pmap_extract and similar routines.
                 */
                simple_lock(&pmap->lock);

                {
                    register vm_offset_t va;

                    va = pv_e->va;
                    pte = pmap_pte(pmap, va);

                    /*
                     * Consistency checks.
                     */
                    /* assert(*pte & INTEL_PTE_VALID); XXX */
                    /* assert(pte_to_phys(*pte) == phys); */

                    /*
                     * Invalidate TLBs for all CPUs using this mapping.
                     */
                    PMAP_INVALIDATE_PAGE(pmap, va);
                }

                /*
                 * Remove the mapping if new protection is NONE
                 * or if write-protecting a kernel mapping.
                 */
                if (remove || pmap == kernel_pmap) {
                    /*
                     * Remove the mapping, collecting any modify bits.
                     */
                    {
                        register int    i = ptes_per_vm_page;

                        do {
                            pmap_phys_attributes[pai] |=
                                *pte & (PHYS_MODIFIED|PHYS_REFERENCED);
                            *pte++ = 0;
                        } while (--i > 0);
                    }

                    assert(pmap->stats.resident_count >= 1);
                    pmap->stats.resident_count--;

                    /*
                     * Remove the pv_entry.
                     */
                    if (pv_e == pv_h) {
                        /*
                         * Fix up head later.
                         */
                        pv_h->pmap = PMAP_NULL;
                    }
                    else {
                        /*
                         * Delete this entry.
                         */
                        prev->next = pv_e->next;
                        PV_FREE(pv_e);
                    }
                }
                else {
                    /*
                     * Write-protect.
                     */
                    register int i = ptes_per_vm_page;

                    do {
                        *pte &= ~INTEL_PTE_WRITE;
                        pte++;
                    } while (--i > 0);

                    /*
                     * Advance prev.
                     */
                    prev = pv_e;
                }

                simple_unlock(&pmap->lock);

            } while ((pv_e = prev->next) != PV_ENTRY_NULL);

            /*
             * If pv_head mapping was removed, fix it up.
             */
            if (pv_h->pmap == PMAP_NULL) {
                pv_e = pv_h->next;
                if (pv_e != PV_ENTRY_NULL) {
                    *pv_h = *pv_e;
                    PV_FREE(pv_e);
                }
            }
        }

        PMAP_WRITE_UNLOCK(spl);
}

/*
 *      Set the physical protection on the
 *      specified range of this map as requested.
 *      Will not increase permissions.
 */
void
pmap_protect(
        pmap_t          map,
        vm_offset_t     s,
        vm_offset_t     e,
        vm_prot_t       prot)
{
        register pt_entry_t     *pde;
        register pt_entry_t     *spte, *epte;
        vm_offset_t             l;
        spl_t           spl;


        if (map == PMAP_NULL)
                return;

        /*
         * Determine the new protection.
         */
        switch (prot) {
            case VM_PROT_READ:
            case VM_PROT_READ|VM_PROT_EXECUTE:
                break;
            case VM_PROT_READ|VM_PROT_WRITE:
            case VM_PROT_ALL:
                return; /* nothing to do */
            default:
                pmap_remove(map, s, e);
                return;
        }

        /*
         * If write-protecting in the kernel pmap,
         * remove the mappings; the i386 ignores
         * the write-permission bit in kernel mode.
         *
         * XXX should be #if'd for i386
         */

        if (cpuid_family == CPUID_FAMILY_386)
            if (map == kernel_pmap) {
                    pmap_remove(map, s, e);
                    return;
            }

        SPLVM(spl);
        simple_lock(&map->lock);


        pde = pmap_pde(map, s);
        while (s < e) {
            l = (s + PDE_MAPPED_SIZE) & ~(PDE_MAPPED_SIZE-1);
            if (l > e)
                l = e;
            if (*pde & INTEL_PTE_VALID) {
                spte = (pt_entry_t *)ptetokv(*pde);
                spte = &spte[ptenum(s)];
                epte = &spte[intel_btop(l-s)];

                while (spte < epte) {
                    if (*spte & INTEL_PTE_VALID)
                        *spte &= ~INTEL_PTE_WRITE;
                    spte++;
                }
            }
            s = l;
            pde++;
        }

        PMAP_FLUSH_TLBS();

        simple_unlock(&map->lock);
        SPLX(spl);
}



/*
 *      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 cannot 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(
        register pmap_t         pmap,
        vm_offset_t             v,
        register vm_offset_t    pa,
        vm_prot_t               prot,
        unsigned int            flags,
        boolean_t               wired)
{
        register pt_entry_t     *pte;
        register pv_entry_t     pv_h;
        register int            i, pai;
        pv_entry_t              pv_e;
        pt_entry_t              template;
        spl_t                   spl;
        vm_offset_t             old_pa;

        XPR(0x80000000, "%x/%x: pmap_enter %x/%x/%x\n",
            current_thread()->top_act,
            current_thread(), 
            pmap, v, pa);

        assert(pa != vm_page_fictitious_addr);
        if (pmap_debug)
                printf("pmap(%x, %x)\n", v, pa);
        if (pmap == PMAP_NULL)
                return;

        if (cpuid_family == CPUID_FAMILY_386)
        if (pmap == kernel_pmap && (prot & VM_PROT_WRITE) == 0
            && !wired /* hack for io_wire */ ) {
            /*
             *  Because the 386 ignores write protection in kernel mode,
             *  we cannot enter a read-only kernel mapping, and must
             *  remove an existing mapping if changing it.
             *
             *  XXX should be #if'd for i386
             */
            PMAP_READ_LOCK(pmap, spl);

            pte = pmap_pte(pmap, v);
            if (pte != PT_ENTRY_NULL && pte_to_pa(*pte) != 0) {
                /*
                 *      Invalidate the translation buffer,
                 *      then remove the mapping.
                 */
                PMAP_INVALIDATE_PAGE(pmap, v);
                pmap_remove_range(pmap, v, pte,
                                  pte + ptes_per_vm_page);
            }
            PMAP_READ_UNLOCK(pmap, spl);
            return;
        }

        /*
         *      Must allocate a new pvlist entry while we're unlocked;
         *      zalloc may cause pageout (which will lock the pmap system).
         *      If we determine we need a pvlist entry, we will unlock
         *      and allocate one.  Then we will retry, throughing away
         *      the allocated entry later (if we no longer need it).
         */
        pv_e = PV_ENTRY_NULL;
Retry:
        PMAP_READ_LOCK(pmap, spl);

        /*
         *      Expand pmap to include this pte.  Assume that
         *      pmap is always expanded to include enough hardware
         *      pages to map one VM page.
         */

        while ((pte = pmap_pte(pmap, v)) == PT_ENTRY_NULL) {
                /*
                 *      Must unlock to expand the pmap.
                 */
                PMAP_READ_UNLOCK(pmap, spl);

                pmap_expand(pmap, v);

                PMAP_READ_LOCK(pmap, spl);
        }
        /*
         *      Special case if the physical page is already mapped
         *      at this address.
         */
        old_pa = pte_to_pa(*pte);
        if (old_pa == pa) {
            /*
             *  May be changing its wired attribute or protection
             */
                
            template = pa_to_pte(pa) | INTEL_PTE_VALID;
            if (pmap != kernel_pmap)
                template |= INTEL_PTE_USER;
            if (prot & VM_PROT_WRITE)
                template |= INTEL_PTE_WRITE;
            if (wired) {
                template |= INTEL_PTE_WIRED;
                if (!iswired(*pte))
                    pmap->stats.wired_count++;
            }
            else {
                if (iswired(*pte)) {
                    assert(pmap->stats.wired_count >= 1);
                    pmap->stats.wired_count--;
                }
            }

            PMAP_INVALIDATE_PAGE(pmap, v);

            i = ptes_per_vm_page;
            do {
                if (*pte & INTEL_PTE_MOD)
                    template |= INTEL_PTE_MOD;
                WRITE_PTE(pte, template)
                pte++;
                pte_increment_pa(template);
            } while (--i > 0);

            goto Done;
        }

        /*
         *      Outline of code from here:
         *         1) If va was mapped, update TLBs, remove the mapping
         *            and remove old pvlist entry.
         *         2) Add pvlist entry for new mapping
         *         3) Enter new mapping.
         *
         *      SHARING_FAULTS complicates this slightly in that it cannot
         *      replace the mapping, but must remove it (because adding the
         *      pvlist entry for the new mapping may remove others), and
         *      hence always enters the new mapping at step 3)
         *
         *      If the old physical page is not managed step 1) is skipped
         *      (except for updating the TLBs), and the mapping is
         *      overwritten at step 3).  If the new physical page is not
         *      managed, step 2) is skipped.
         */

        if (old_pa != (vm_offset_t) 0) {

            PMAP_INVALIDATE_PAGE(pmap, v);

#if     DEBUG_PTE_PAGE
            if (pmap != kernel_pmap)
                ptep_check(get_pte_page(pte));
#endif  /* DEBUG_PTE_PAGE */

            /*
             *  Don't do anything to pages outside valid memory here.
             *  Instead convince the code that enters a new mapping
             *  to overwrite the old one.
             */

            if (valid_page(old_pa)) {

                pai = pa_index(old_pa);
                LOCK_PVH(pai);

                assert(pmap->stats.resident_count >= 1);
                pmap->stats.resident_count--;
                if (iswired(*pte)) {
                    assert(pmap->stats.wired_count >= 1);
                    pmap->stats.wired_count--;
                }
                i = ptes_per_vm_page;
                do {
                    pmap_phys_attributes[pai] |=
                        *pte & (PHYS_MODIFIED|PHYS_REFERENCED);
                    WRITE_PTE(pte, 0)
                    pte++;
                    pte_increment_pa(template);
                } while (--i > 0);

                /*
                 * Put pte back to beginning of page since it'll be
                 * used later to enter the new page.
                 */
                pte -= ptes_per_vm_page;

                /*
                 *      Remove the mapping from the pvlist for
                 *      this physical page.
                 */
                {
                    register pv_entry_t prev, cur;

                    pv_h = pai_to_pvh(pai);
                    if (pv_h->pmap == PMAP_NULL) {
                        panic("pmap_enter: null pv_list!");
                    }
                    if (pv_h->va == v && pv_h->pmap == pmap) {
                        /*
                         * Header is the pv_entry.  Copy the next one
                         * to header and free the next one (we cannot
                         * free the header)
                         */
                        cur = pv_h->next;
                        if (cur != PV_ENTRY_NULL) {
                            *pv_h = *cur;
                            pv_e = cur;
                        }
                        else {
                            pv_h->pmap = PMAP_NULL;
                        }
                    }
                    else {
                        cur = pv_h;
                        do {
                            prev = cur;
                            if ((cur = prev->next) == PV_ENTRY_NULL) {
                                panic("pmap_enter: mapping not in pv_list!");
                            }
                        } while (cur->va != v || cur->pmap != pmap);
                        prev->next = cur->next;
                        pv_e = cur;
                    }
                }
                UNLOCK_PVH(pai);
            }
            else {

                /*
                 *      old_pa is not managed.  Pretend it's zero so code
                 *      at Step 3) will enter new mapping (overwriting old
                 *      one).  Do removal part of accounting.
                 */
                old_pa = (vm_offset_t) 0;
                assert(pmap->stats.resident_count >= 1);
                pmap->stats.resident_count--;
                if (iswired(*pte)) {
                    assert(pmap->stats.wired_count >= 1);
                    pmap->stats.wired_count--;
                }
            }
        }

        if (valid_page(pa)) {

            /*
             *  Step 2) Enter the mapping in the PV list for this
             *  physical page.
             */

            pai = pa_index(pa);


#if SHARING_FAULTS
RetryPvList:
            /*
             * We can return here from the sharing fault code below
             * in case we removed the only entry on the pv list and thus
             * must enter the new one in the list header.
             */
#endif /* SHARING_FAULTS */
            LOCK_PVH(pai);
            pv_h = pai_to_pvh(pai);

            if (pv_h->pmap == PMAP_NULL) {
                /*
                 *      No mappings yet
                 */
                pv_h->va = v;
                pv_h->pmap = pmap;
                pv_h->next = PV_ENTRY_NULL;
            }
            else {
#if     DEBUG
                {
                    /*
                     * check that this mapping is not already there
                     * or there is no alias for this mapping in the same map
                     */
                    pv_entry_t  e = pv_h;
                    while (e != PV_ENTRY_NULL) {
                        if (e->pmap == pmap && e->va == v)
                            panic("pmap_enter: already in pv_list");
                        e = e->next;
                    }
                }
#endif  /* DEBUG */
#if SHARING_FAULTS
                {
                    /*
                     * do sharing faults.
                     * if we find an entry on this pv list in the same address
                     * space, remove it.  we know there will not be more
                     * than one. 
                     */
                    pv_entry_t  e = pv_h;
                    pt_entry_t      *opte;

                    while (e != PV_ENTRY_NULL) {
                        if (e->pmap == pmap) {
                            /*
                             *  Remove it, drop pv list lock first.
                             */
                            UNLOCK_PVH(pai);

                            opte = pmap_pte(pmap, e->va);
                            assert(opte != PT_ENTRY_NULL);
                            /*
                             *  Invalidate the translation buffer,
                             *  then remove the mapping.
                             */
                             PMAP_INVALIDATE_PAGE(pmap, e->va);
                             pmap_remove_range(pmap, e->va, opte,
                                                      opte + ptes_per_vm_page);
                             /*
                              * We could have remove the head entry,
                              * so there could be no more entries
                              * and so we have to use the pv head entry.
                              * so, go back to the top and try the entry
                              * again.
                              */
                             goto RetryPvList;
                        }
                        e = e->next;
                    }

                    /*
                     * check that this mapping is not already there
                     */
                    e = pv_h;
                    while (e != PV_ENTRY_NULL) {
                        if (e->pmap == pmap)
                            panic("pmap_enter: alias in pv_list");
                        e = e->next;
                    }
                }
#endif /* SHARING_FAULTS */
#if DEBUG_ALIAS
                {
                    /*
                     * check for aliases within the same address space.
                     */
                    pv_entry_t  e = pv_h;
                    vm_offset_t     rpc = get_rpc();

                    while (e != PV_ENTRY_NULL) {
                        if (e->pmap == pmap) {
                            /*
                             * log this entry in the alias ring buffer
                             * if it's not there already.
                             */
                            struct pmap_alias *pma;
                            int ii, logit;

                            logit = TRUE;
                            for (ii = 0; ii < pmap_alias_index; ii++) {
                                if (pmap_aliasbuf[ii].rpc == rpc) {
                                    /* found it in the log already */
                                    logit = FALSE;
                                    break;
                                }
                            }
                            if (logit) {
                                pma = &pmap_aliasbuf[pmap_alias_index];
                                pma->pmap = pmap;
                                pma->va = v;
                                pma->rpc = rpc;
                                pma->cookie = PMAP_ALIAS_COOKIE;
                                if (++pmap_alias_index >= PMAP_ALIAS_MAX)
                                    panic("pmap_enter: exhausted alias log");
                            }
                        }
                        e = e->next;
                    }
                }
#endif /* DEBUG_ALIAS */
                /*
                 *      Add new pv_entry after header.
                 */
                if (pv_e == PV_ENTRY_NULL) {
                    PV_ALLOC(pv_e);
                    if (pv_e == PV_ENTRY_NULL) {
                        UNLOCK_PVH(pai);
                        PMAP_READ_UNLOCK(pmap, spl);

                        /*
                         * Refill from zone.
                         */
                        pv_e = (pv_entry_t) zalloc(pv_list_zone);
                        goto Retry;
                    }
                }
                pv_e->va = v;
                pv_e->pmap = pmap;
                pv_e->next = pv_h->next;
                pv_h->next = pv_e;
                /*
                 *      Remember that we used the pvlist entry.
                 */
                pv_e = PV_ENTRY_NULL;
            }
            UNLOCK_PVH(pai);
        }

        /*
         * Step 3) Enter and count the mapping.
         */

        pmap->stats.resident_count++;

        /*
         *      Build a template to speed up entering -
         *      only the pfn changes.
         */
        template = pa_to_pte(pa) | INTEL_PTE_VALID;
        if (pmap != kernel_pmap)
                template |= INTEL_PTE_USER;
        if (prot & VM_PROT_WRITE)
                template |= INTEL_PTE_WRITE;
        if (wired) {
                template |= INTEL_PTE_WIRED;
                pmap->stats.wired_count++;
        }
        i = ptes_per_vm_page;
        do {
                WRITE_PTE(pte, template)
                pte++;
                pte_increment_pa(template);
        } while (--i > 0);
Done:
        if (pv_e != PV_ENTRY_NULL) {
            PV_FREE(pv_e);
        }

        PMAP_READ_UNLOCK(pmap, spl);
}

/*
 *      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(
        register pmap_t map,
        vm_offset_t     v,
        boolean_t       wired)
{
        register pt_entry_t     *pte;
        register int            i;
        spl_t                   spl;

#if 0
        /*
         *      We must grab the pmap system lock because we may
         *      change a pte_page queue.
         */
        PMAP_READ_LOCK(map, spl);

        if ((pte = pmap_pte(map, v)) == PT_ENTRY_NULL)
                panic("pmap_change_wiring: pte missing");

        if (wired && !iswired(*pte)) {
            /*
             *  wiring down mapping
             */
            map->stats.wired_count++;
            i = ptes_per_vm_page;
            do {
                *pte++ |= INTEL_PTE_WIRED;
            } while (--i > 0);
        }
        else if (!wired && iswired(*pte)) {
            /*
             *  unwiring mapping
             */
            assert(map->stats.wired_count >= 1);
            map->stats.wired_count--;
            i = ptes_per_vm_page;
            do {
                *pte++ &= ~INTEL_PTE_WIRED;
            } while (--i > 0);
        }

        PMAP_READ_UNLOCK(map, spl);

#else
        return;
#endif

}

/*
 *      Routine:        pmap_extract
 *      Function:
 *              Extract the physical page address associated
 *              with the given map/virtual_address pair.
 */

vm_offset_t
pmap_extract(
        register pmap_t pmap,
        vm_offset_t     va)
{
        register pt_entry_t     *pte;
        register vm_offset_t    pa;
        spl_t                   spl;

        SPLVM(spl);
        simple_lock(&pmap->lock);
        if ((pte = pmap_pte(pmap, va)) == PT_ENTRY_NULL)
            pa = (vm_offset_t) 0;
        else if (!(*pte & INTEL_PTE_VALID))
            pa = (vm_offset_t) 0;
        else
            pa = pte_to_pa(*pte) + (va & INTEL_OFFMASK);
        simple_unlock(&pmap->lock);
        SPLX(spl);
        return(pa);
}

/*
 *      Routine:        pmap_expand
 *
 *      Expands a pmap to be able to map the specified virtual address.
 *
 *      Allocates new virtual memory for the P0 or P1 portion of the
 *      pmap, then re-maps the physical pages that were in the old
 *      pmap to be in the new pmap.
 *
 *      Must be called with the pmap system and the pmap unlocked,
 *      since these must be unlocked to use vm_allocate or vm_deallocate.
 *      Thus it must be called in a loop that checks whether the map
 *      has been expanded enough.
 *      (We won't loop forever, since page tables aren't shrunk.)
 */
void
pmap_expand(
        register pmap_t         map,
        register vm_offset_t    v)
{
        pt_entry_t              *pdp;
        register vm_page_t      m;
        register vm_offset_t    pa;
        register int            i;
        spl_t                   spl;

        if (map == kernel_pmap)
            panic("pmap_expand");

        /*
         *      We cannot allocate the pmap_object in pmap_init,
         *      because it is called before the zone package is up.
         *      Allocate it now if it is missing.
         */
        if (pmap_object == VM_OBJECT_NULL)
            pmap_object = vm_object_allocate(avail_end);

        /*
         *      Allocate a VM page for the level 2 page table entries.
         */
        while ((m = vm_page_grab()) == VM_PAGE_NULL)
                VM_PAGE_WAIT();

        /*
         *      Map the page to its physical address so that it
         *      can be found later.
         */
        pa = m->phys_addr;
        vm_object_lock(pmap_object);
        vm_page_insert(m, pmap_object, pa);
        vm_page_lock_queues();
        vm_page_wire(m);
        inuse_ptepages_count++;
        vm_object_unlock(pmap_object);
        vm_page_unlock_queues();

        /*
         *      Zero the page.
         */
        memset((void *)phystokv(pa), 0, PAGE_SIZE);

        PMAP_READ_LOCK(map, spl);
        /*
         *      See if someone else expanded us first
         */
        if (pmap_pte(map, v) != PT_ENTRY_NULL) {
                PMAP_READ_UNLOCK(map, spl);
                vm_object_lock(pmap_object);
                vm_page_lock_queues();
                vm_page_free(m);
                inuse_ptepages_count--;
                vm_page_unlock_queues();
                vm_object_unlock(pmap_object);
                return;
        }

        /*
         *      Set the page directory entry for this page table.
         *      If we have allocated more than one hardware page,
         *      set several page directory entries.
         */

        i = ptes_per_vm_page;
        pdp = &map->dirbase[pdenum(map, v) & ~(i-1)];
        do {
            *pdp = pa_to_pte(pa)
                | INTEL_PTE_VALID
                | INTEL_PTE_USER
                | INTEL_PTE_WRITE;
            pdp++;
            pa += INTEL_PGBYTES;
        } while (--i > 0);

        PMAP_READ_UNLOCK(map, spl);
        return;
}

/*
 *      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.
 */
#if     0
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)
{
#ifdef  lint
        dst_pmap++; src_pmap++; dst_addr++; len++; src_addr++;
#endif  /* lint */
}
#endif/*        0 */

int     collect_ref;
int     collect_unref;

/*
 *      Routine:        pmap_collect
 *      Function:
 *              Garbage collects the physical map system for
 *              pages which are no longer used.
 *              Success need not be guaranteed -- that is, there
 *              may well be pages which are not referenced, but
 *              others may be collected.
 *      Usage:
 *              Called by the pageout daemon when pages are scarce.
 */
void
pmap_collect(
        pmap_t          p)
{
        register pt_entry_t     *pdp, *ptp;
        pt_entry_t              *eptp;
        vm_offset_t             pa;
        int                     wired;
        spl_t                   spl;

        if (p == PMAP_NULL)
                return;

        if (p == kernel_pmap)
                return;

        /*
         *      Garbage collect map.
         */
        PMAP_READ_LOCK(p, spl);
        PMAP_FLUSH_TLBS();

        for (pdp = p->dirbase;
             pdp < &p->dirbase[pdenum(p, LINEAR_KERNEL_ADDRESS)];
             pdp += ptes_per_vm_page)
        {
            if (*pdp & INTEL_PTE_VALID) 
              if(*pdp & INTEL_PTE_REF) {
                *pdp &= ~INTEL_PTE_REF;
                collect_ref++;
              } else {
                collect_unref++;
                pa = pte_to_pa(*pdp);
                ptp = (pt_entry_t *)phystokv(pa);
                eptp = ptp + NPTES*ptes_per_vm_page;

                /*
                 * If the pte page has any wired mappings, we cannot
                 * free it.
                 */
                wired = 0;
                {
                    register pt_entry_t *ptep;
                    for (ptep = ptp; ptep < eptp; ptep++) {
                        if (iswired(*ptep)) {
                            wired = 1;
                            break;
                        }
                    }
                }
                if (!wired) {
                    /*
                     * Remove the virtual addresses mapped by this pte page.
                     */
                    pmap_remove_range(p,
                                pdetova(pdp - p->dirbase),
                                ptp,
                                eptp);

                    /*
                     * Invalidate the page directory pointer.
                     */
                    {
                        register int i = ptes_per_vm_page;
                        register pt_entry_t *pdep = pdp;
                        do {
                            *pdep++ = 0;
                        } while (--i > 0);
                    }

                    PMAP_READ_UNLOCK(p, spl);

                    /*
                     * And free the pte page itself.
                     */
                    {
                        register vm_page_t m;

                        vm_object_lock(pmap_object);
                        m = vm_page_lookup(pmap_object, pa);
                        if (m == VM_PAGE_NULL)
                            panic("pmap_collect: pte page not in object");
                        vm_page_lock_queues();
                        vm_page_free(m);
                        inuse_ptepages_count--;
                        vm_page_unlock_queues();
                        vm_object_unlock(pmap_object);
                    }

                    PMAP_READ_LOCK(p, spl);
                }
            }
        }
        PMAP_READ_UNLOCK(p, spl);
        return;

}

/*
 *      Routine:        pmap_kernel
 *      Function:
 *              Returns the physical map handle for the kernel.
 */
#if     0
pmap_t
pmap_kernel(void)
{
        return (kernel_pmap);
}
#endif/*        0 */

/*
 *      pmap_zero_page zeros the specified (machine independent) page.
 *      See machine/phys.c or machine/phys.s for implementation.
 */
#if     0
void
pmap_zero_page(
        register vm_offset_t    phys)
{
        register int    i;

        assert(phys != vm_page_fictitious_addr);
        i = PAGE_SIZE / INTEL_PGBYTES;
        phys = intel_pfn(phys);

        while (i--)
                zero_phys(phys++);
}
#endif/*        0 */

/*
 *      pmap_copy_page copies the specified (machine independent) page.
 *      See machine/phys.c or machine/phys.s for implementation.
 */
#if     0
void
pmap_copy_page(
        vm_offset_t     src,
        vm_offset_t     dst)
{
        int     i;

        assert(src != vm_page_fictitious_addr);
        assert(dst != vm_page_fictitious_addr);
        i = PAGE_SIZE / INTEL_PGBYTES;

        while (i--) {
                copy_phys(intel_pfn(src), intel_pfn(dst));
                src += INTEL_PGBYTES;
                dst += INTEL_PGBYTES;
        }
}
#endif/*        0 */

/*
 *      Routine:        pmap_pageable
 *      Function:
 *              Make the specified pages (by pmap, offset)
 *              pageable (or not) as requested.
 *
 *              A page which is not pageable may not take
 *              a fault; therefore, its page table entry
 *              must remain valid for the duration.
 *
 *              This routine is merely advisory; pmap_enter
 *              will specify that these pages are to be wired
 *              down (or not) as appropriate.
 */
void
pmap_pageable(
        pmap_t          pmap,
        vm_offset_t     start,
        vm_offset_t     end,
        boolean_t       pageable)
{
#ifdef  lint
        pmap++; start++; end++; pageable++;
#endif  /* lint */
}

/*
 *      Clear specified attribute bits.
 */
void
phys_attribute_clear(
        vm_offset_t     phys,
        int             bits)
{
        pv_entry_t              pv_h;
        register pv_entry_t     pv_e;
        register pt_entry_t     *pte;
        int                     pai;
        register pmap_t         pmap;
        spl_t                   spl;

        assert(phys != vm_page_fictitious_addr);
        if (!valid_page(phys)) {
            /*
             *  Not a managed page.
             */
            return;
        }

        /*
         *      Lock the pmap system first, since we will be changing
         *      several pmaps.
         */

        PMAP_WRITE_LOCK(spl);

        pai = pa_index(phys);
        pv_h = pai_to_pvh(pai);

        /*
         * Walk down PV list, clearing all modify or reference bits.
         * We do not have to lock the pv_list because we have
         * the entire pmap system locked.
         */
        if (pv_h->pmap != PMAP_NULL) {
            /*
             * There are some mappings.
             */
            for (pv_e = pv_h; pv_e != PV_ENTRY_NULL; pv_e = pv_e->next) {

                pmap = pv_e->pmap;
                /*
                 * Lock the pmap to block pmap_extract and similar routines.
                 */
                simple_lock(&pmap->lock);

                {
                    register vm_offset_t va;

                    va = pv_e->va;
                    pte = pmap_pte(pmap, va);

#if     0
                    /*
                     * Consistency checks.
                     */
                    assert(*pte & INTEL_PTE_VALID);
                    /* assert(pte_to_phys(*pte) == phys); */
#endif

                    /*
                     * Invalidate TLBs for all CPUs using this mapping.
                     */
                    PMAP_INVALIDATE_PAGE(pmap, va);
                }

                /*
                 * Clear modify or reference bits.
                 */
                {
                    register int        i = ptes_per_vm_page;
                    do {
                        *pte++ &= ~bits;
                    } while (--i > 0);
                }
                simple_unlock(&pmap->lock);
            }
        }

        pmap_phys_attributes[pai] &= ~bits;

        PMAP_WRITE_UNLOCK(spl);
}

/*
 *      Check specified attribute bits.
 */
boolean_t
phys_attribute_test(
        vm_offset_t     phys,
        int             bits)
{
        pv_entry_t              pv_h;
        register pv_entry_t     pv_e;
        register pt_entry_t     *pte;
        int                     pai;
        register pmap_t         pmap;
        spl_t                   spl;

        assert(phys != vm_page_fictitious_addr);
        if (!valid_page(phys)) {
            /*
             *  Not a managed page.
             */
            return (FALSE);
        }

        /*
         *      Lock the pmap system first, since we will be checking
         *      several pmaps.
         */

        PMAP_WRITE_LOCK(spl);

        pai = pa_index(phys);
        pv_h = pai_to_pvh(pai);

        if (pmap_phys_attributes[pai] & bits) {
            PMAP_WRITE_UNLOCK(spl);
            return (TRUE);
        }

        /*
         * Walk down PV list, checking all mappings.
         * We do not have to lock the pv_list because we have
         * the entire pmap system locked.
         */
        if (pv_h->pmap != PMAP_NULL) {
            /*
             * There are some mappings.
             */
            for (pv_e = pv_h; pv_e != PV_ENTRY_NULL; pv_e = pv_e->next) {

                pmap = pv_e->pmap;
                /*
                 * Lock the pmap to block pmap_extract and similar routines.
                 */
                simple_lock(&pmap->lock);

                {
                    register vm_offset_t va;

                    va = pv_e->va;
                    pte = pmap_pte(pmap, va);

#if     0
                    /*
                     * Consistency checks.
                     */
                    assert(*pte & INTEL_PTE_VALID);
                    /* assert(pte_to_phys(*pte) == phys); */
#endif
                }

                /*
                 * Check modify or reference bits.
                 */
                {
                    register int        i = ptes_per_vm_page;

                    do {
                        if (*pte++ & bits) {
                            simple_unlock(&pmap->lock);
                            PMAP_WRITE_UNLOCK(spl);
                            return (TRUE);
                        }
                    } while (--i > 0);
                }
                simple_unlock(&pmap->lock);
            }
        }
        PMAP_WRITE_UNLOCK(spl);
        return (FALSE);
}

/*
 *      Set specified attribute bits.
 */
void
phys_attribute_set(
        vm_offset_t     phys,
        int             bits)
{
        int                     spl;

        assert(phys != vm_page_fictitious_addr);
        if (!valid_page(phys)) {
            /*
             *  Not a managed page.
             */
            return;
        }

        /*
         *      Lock the pmap system and set the requested bits in
         *      the phys attributes array.  Don't need to bother with
         *      ptes because the test routine looks here first.
         */

        PMAP_WRITE_LOCK(spl);
        pmap_phys_attributes[pa_index(phys)] |= bits;
        PMAP_WRITE_UNLOCK(spl);
}

/*
 *      Set the modify bit on the specified physical page.
 */

void pmap_set_modify(
        register vm_offset_t    phys)
{
        phys_attribute_set(phys, PHYS_MODIFIED);
}

/*
 *      Clear the modify bits on the specified physical page.
 */

void
pmap_clear_modify(
        register vm_offset_t    phys)
{
        phys_attribute_clear(phys, PHYS_MODIFIED);
}

/*
 *      pmap_is_modified:
 *
 *      Return whether or not the specified physical page is modified
 *      by any physical maps.
 */

boolean_t
pmap_is_modified(
        register vm_offset_t    phys)
{
        return (phys_attribute_test(phys, PHYS_MODIFIED));
}

/*
 *      pmap_clear_reference:
 *
 *      Clear the reference bit on the specified physical page.
 */

void
pmap_clear_reference(
        vm_offset_t     phys)
{
        phys_attribute_clear(phys, PHYS_REFERENCED);
}

/*
 *      pmap_is_referenced:
 *
 *      Return whether or not the specified physical page is referenced
 *      by any physical maps.
 */

boolean_t
pmap_is_referenced(
        vm_offset_t     phys)
{
        return (phys_attribute_test(phys, PHYS_REFERENCED));
}

/*
 *      Set the modify bit on the specified range
 *      of this map as requested.
 *
 *      This optimization stands only if each time the dirty bit
 *      in vm_page_t is tested, it is also tested in the pmap.
 */
void
pmap_modify_pages(
        pmap_t          map,
        vm_offset_t     s,
        vm_offset_t     e)
{
        spl_t                   spl;
        register pt_entry_t     *pde;
        register pt_entry_t     *spte, *epte;
        vm_offset_t             l;

        if (map == PMAP_NULL)
                return;

        PMAP_READ_LOCK(map, spl);

        pde = pmap_pde(map, s);
        while (s && s < e) {
            l = (s + PDE_MAPPED_SIZE) & ~(PDE_MAPPED_SIZE-1);
            if (l > e)
                l = e;
            if (*pde & INTEL_PTE_VALID) {
                spte = (pt_entry_t *)ptetokv(*pde);
                if (l) {
                   spte = &spte[ptenum(s)];
                   epte = &spte[intel_btop(l-s)];
                } else {
                   epte = &spte[intel_btop(PDE_MAPPED_SIZE)];
                   spte = &spte[ptenum(s)];
                }
                while (spte < epte) {
                    if (*spte & INTEL_PTE_VALID) {
                        *spte |= (INTEL_PTE_MOD | INTEL_PTE_WRITE);
                    }
                    spte++;
                }
            }
            s = l;
            pde++;
        }
        PMAP_FLUSH_TLBS();
        PMAP_READ_UNLOCK(map, spl);
}


void 
invalidate_icache(vm_offset_t addr, unsigned cnt, int phys)
{
        return;
}
void 
flush_dcache(vm_offset_t addr, unsigned count, int phys)
{
        return;
}

#if     NCPUS > 1

void inline
pmap_wait_for_clear()
{
        register int            my_cpu;
        spl_t                   s;
        register pmap_t         my_pmap;

        mp_disable_preemption();
        my_cpu = cpu_number();
        

        my_pmap = real_pmap[my_cpu];

        if (!(my_pmap && pmap_in_use(my_pmap, my_cpu)))
                my_pmap = kernel_pmap;

        /*
         *      Raise spl to splhigh (above splip) to block out pmap_extract
         *      from IO code (which would put this cpu back in the active
         *      set).
         */
        s = splhigh();

        /*
         *      Wait for any pmap updates in progress, on either user
         *      or kernel pmap.
         */
         while (*(volatile hw_lock_t)&my_pmap->lock.interlock ||
          *(volatile hw_lock_t)&kernel_pmap->lock.interlock) {
                continue;
        }

        splx(s);
        mp_enable_preemption();
}

void
pmap_flush_tlb_interrupt(void) {
        pmap_wait_for_clear();

        flush_tlb();
}

void
pmap_reload_tlb_interrupt(void) {
        pmap_wait_for_clear();

        set_cr3(kernel_pmap->pdirbase);
}

        
#endif  /* NCPUS > 1 */

#if     MACH_KDB

/* show phys page mappings and attributes */

extern void     db_show_page(vm_offset_t pa);

void
db_show_page(vm_offset_t pa)
{
        pv_entry_t      pv_h;
        int             pai;
        char            attr;
        
        pai = pa_index(pa);
        pv_h = pai_to_pvh(pai);

        attr = pmap_phys_attributes[pai];
        printf("phys page %x ", pa);
        if (attr & PHYS_MODIFIED)
                printf("modified, ");
        if (attr & PHYS_REFERENCED)
                printf("referenced, ");
        if (pv_h->pmap || pv_h->next)
                printf(" mapped at\n");
        else
                printf(" not mapped\n");
        for (; pv_h; pv_h = pv_h->next)
                if (pv_h->pmap)
                        printf("%x in pmap %x\n", pv_h->va, pv_h->pmap);
}

#endif /* MACH_KDB */

#if     MACH_KDB
void db_kvtophys(vm_offset_t);
void db_show_vaddrs(pt_entry_t  *);

/*
 *      print out the results of kvtophys(arg)
 */
void
db_kvtophys(
        vm_offset_t     vaddr)
{
        db_printf("0x%x", kvtophys(vaddr));
}

/*
 *      Walk the pages tables.
 */
void
db_show_vaddrs(
        pt_entry_t      *dirbase)
{
        pt_entry_t      *ptep, *pdep, tmp;
        int             x, y, pdecnt, ptecnt;

        if (dirbase == 0) {
                dirbase = kernel_pmap->dirbase;
        }
        if (dirbase == 0) {
                db_printf("need a dirbase...\n");
                return;
        }
        dirbase = (pt_entry_t *) ((unsigned long) dirbase & ~INTEL_OFFMASK);

        db_printf("dirbase: 0x%x\n", dirbase);

        pdecnt = ptecnt = 0;
        pdep = &dirbase[0];
        for (y = 0; y < NPDES; y++, pdep++) {
                if (((tmp = *pdep) & INTEL_PTE_VALID) == 0) {
                        continue;
                }
                pdecnt++;
                ptep = (pt_entry_t *) ((*pdep) & ~INTEL_OFFMASK);
                db_printf("dir[%4d]: 0x%x\n", y, *pdep);
                for (x = 0; x < NPTES; x++, ptep++) {
                        if (((tmp = *ptep) & INTEL_PTE_VALID) == 0) {
                                continue;
                        }
                        ptecnt++;
                        db_printf("   tab[%4d]: 0x%x, va=0x%x, pa=0x%x\n",
                                x,
                                *ptep,
                                (y << 22) | (x << 12),
                                *ptep & ~INTEL_OFFMASK);
                }
        }

        db_printf("total: %d tables, %d page table entries.\n", pdecnt, ptecnt);

}
#endif  /* MACH_KDB */

#include <mach_vm_debug.h>
#if     MACH_VM_DEBUG
#include <vm/vm_debug.h>

int
pmap_list_resident_pages(
        register pmap_t         pmap,
        register vm_offset_t    *listp,
        register int            space)
{
        return 0;
}
#endif  /* MACH_VM_DEBUG */

#ifdef MACH_BSD
/*
 * pmap_pagemove
 *
 * BSD support routine to reassign virtual addresses.
 */

void
pmap_movepage(unsigned long from, unsigned long to, vm_size_t size)
{
        spl_t   spl;
        pt_entry_t      *pte, saved_pte;
        /* Lock the kernel map */


        while (size > 0) {
                PMAP_READ_LOCK(kernel_pmap, spl);
                pte = pmap_pte(kernel_pmap, from);
                if (pte == NULL)
                        panic("pmap_pagemove from pte NULL");
                saved_pte = *pte;
                PMAP_READ_UNLOCK(kernel_pmap, spl);

                pmap_enter(kernel_pmap, to, i386_trunc_page(*pte),
                        VM_PROT_READ|VM_PROT_WRITE, 0, *pte & INTEL_PTE_WIRED);

                pmap_remove(kernel_pmap, from, from+PAGE_SIZE);

                PMAP_READ_LOCK(kernel_pmap, spl);
                pte = pmap_pte(kernel_pmap, to);
                if (pte == NULL)
                        panic("pmap_pagemove 'to' pte NULL");

                *pte = saved_pte;
                PMAP_READ_UNLOCK(kernel_pmap, spl);

                from += PAGE_SIZE;
                to += PAGE_SIZE;
                size -= PAGE_SIZE;
        }

        /* Get the processors to update the TLBs */
        PMAP_FLUSH_TLBS();

}

kern_return_t bmapvideo(vm_offset_t *info);
kern_return_t bmapvideo(vm_offset_t *info) {

        extern struct vc_info vinfo;
#ifdef NOTIMPLEMENTED
        (void)copyout((char *)&vinfo, (char *)info, sizeof(struct vc_info));    /* Copy out the video info */
#endif
        return KERN_SUCCESS;
}

kern_return_t bmapmap(vm_offset_t va, vm_offset_t pa, vm_size_t size, vm_prot_t prot, int attr);
kern_return_t bmapmap(vm_offset_t va, vm_offset_t pa, vm_size_t size, vm_prot_t prot, int attr) {
        
#ifdef NOTIMPLEMENTED
        pmap_map_block(current_act()->task->map->pmap, va, pa, size, prot, attr);       /* Map it in */
#endif
        return KERN_SUCCESS;
}

kern_return_t bmapmapr(vm_offset_t va);
kern_return_t bmapmapr(vm_offset_t va) {
        
#ifdef NOTIMPLEMENTED
        mapping_remove(current_act()->task->map->pmap, va);     /* Remove map */
#endif
        return KERN_SUCCESS;
}
#endif

/* temporary workaround */
boolean_t
coredumpok(vm_map_t map, vm_offset_t va)
{
  pt_entry_t *ptep;
  ptep = pmap_pte(map->pmap, va);
  if (0 == ptep) return FALSE;
  return ((*ptep & (INTEL_PTE_NCACHE|INTEL_PTE_WIRED)) != (INTEL_PTE_NCACHE|INTEL_PTE_WIRED));
}