FreeBSD/Linux Kernel Cross Reference
sys/osfmk/i386/pmap.c

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    /*
     * 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
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     * software, derivative works or modified versions, and any portions
     * thereof, and that both notices appear in supporting documentation.
     * 
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     * CONDITION.  CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND FOR
     * ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
     * 
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     * 
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     * 
     * any improvements or extensions that they make and grant Carnegie Mellon
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    /*
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    /*
     *      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 <string.h>
    #include <norma_vm.h>
    #include <mach_kdb.h>
    #include <mach_ldebug.h>
    
    #include <libkern/OSAtomic.h>
    
    #include <mach/machine/vm_types.h>
    
   #include <mach/boolean.h>
   #include <kern/thread.h>
   #include <kern/zalloc.h>
   #include <kern/queue.h>
   
   #include <kern/lock.h>
   #include <kern/kalloc.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>
   #include <i386/cpu_data.h>
   #include <i386/cpu_number.h>
   #include <i386/machine_cpu.h>
   #include <i386/seg.h>
   #include <i386/serial_io.h>
   #include <i386/cpu_capabilities.h>
   #include <i386/machine_routines.h>
   #include <i386/proc_reg.h>
   #include <i386/tsc.h>
   #include <i386/acpi.h>
   #include <i386/pmap_internal.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 <vm/vm_protos.h>
   
   #include <i386/mp.h>
   #include <i386/mp_desc.h>
   #include <i386/i386_lowmem.h>
   
   
   /* #define DEBUGINTERRUPTS 1  uncomment to ensure pmap callers have interrupts enabled */
   #ifdef DEBUGINTERRUPTS
   #define pmap_intr_assert() {if (processor_avail_count > 1 && !ml_get_interrupts_enabled()) panic("pmap interrupt assert %s, %d",__FILE__, __LINE__);}
   #else
   #define pmap_intr_assert()
   #endif
   
   #ifdef IWANTTODEBUG
   #undef  DEBUG
   #define DEBUG 1
   #define POSTCODE_DELAY 1
   #include <i386/postcode.h>
   #endif /* IWANTTODEBUG */
   
   /*
    * Forward declarations for internal functions.
    */
   
   void            pmap_remove_range(
                           pmap_t          pmap,
                           vm_map_offset_t va,
                           pt_entry_t      *spte,
                           pt_entry_t      *epte);
   
   void            phys_attribute_clear(
                           ppnum_t         phys,
                           int             bits);
   
   int             phys_attribute_test(
                           ppnum_t         phys,
                           int             bits);
   
   void            phys_attribute_set(
                           ppnum_t         phys,
                           int             bits);
   
   void            pmap_set_reference(
                           ppnum_t pn);
   
   boolean_t       phys_page_exists(
                           ppnum_t pn);
   
   
   #ifdef PMAP_DEBUG
   void dump_pmap(pmap_t);
   void dump_4GB_pdpt(pmap_t p);
   void dump_4GB_pdpt_thread(thread_t tp);
   #endif
   
   int nx_enabled = 1;                     /* enable no-execute protection */
   #ifdef CONFIG_EMBEDDED
   int allow_data_exec  = 0;       /* no exec from data, embedded is hardcore like that */
   #else
   int allow_data_exec  = VM_ABI_32;       /* 32-bit apps may execute data by default, 64-bit apps may not */
   #endif
   int allow_stack_exec = 0;               /* No apps may execute from the stack by default */
   
   boolean_t cpu_64bit  = FALSE;
   boolean_t pmap_trace = FALSE;
   
   /*
    * when spinning through pmap_remove
    * ensure that we don't spend too much
    * time with preemption disabled.
    * I'm setting the current threshold
    * to 20us
    */
   #define MAX_PREEMPTION_LATENCY_NS 20000
   
   uint64_t max_preemption_latency_tsc = 0;
   
   
   /*
    *      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_rooted_entry_t; the list is the pv_table.
    *
    *      N.B.  with the new combo rooted/hashed scheme it is
    *      only possibly to remove individual non-rooted entries
    *      if they are found via the hashed chains as there is no
    *      way to unlink the singly linked hashed entries if navigated to
    *      via the queue list off the rooted entries.  Think of it as
    *      hash/walk/pull, keeping track of the prev pointer while walking
    *      the singly linked hash list.  All of this is to save memory and
    *      keep both types of pv_entries as small as possible.
    */
   
   /*
   
   PV HASHING Changes - JK 1/2007
   
   Pve's establish physical to virtual mappings.  These are used for aliasing of a 
   physical page to (potentially many) virtual addresses within pmaps. In the previous 
   implementation the structure of the pv_entries (each 16 bytes in size) was
   
   typedef struct pv_entry {
       struct pv_entry_t    next;
       pmap_t                    pmap;
       vm_map_offset_t   va;
   } *pv_entry_t;
   
   An initial array of these is created at boot time, one per physical page of memory, 
   indexed by the physical page number. Additionally, a pool of entries is created from a 
   pv_zone to be used as needed by pmap_enter() when it is creating new mappings.  
   Originally, we kept this pool around because the code in pmap_enter() was unable to 
   block if it needed an entry and none were available - we'd panic.  Some time ago I 
   restructured the pmap_enter() code so that for user pmaps it can block while zalloc'ing 
   a pv structure and restart, removing a panic from the code (in the case of the kernel 
   pmap we cannot block and still panic, so, we keep a separate hot pool for use only on 
   kernel pmaps).  The pool has not been removed since there is a large performance gain 
   keeping freed pv's around for reuse and not suffering the overhead of zalloc for every new pv we need.
   
   As pmap_enter() created new mappings it linked the new pve's for them off the fixed 
   pv array for that ppn (off the next pointer).  These pve's are accessed for several 
   operations, one of them being address space teardown.  In that case, we basically do this
   
           for (every page/pte in the space) {
                   calc pve_ptr from the ppn in the pte
                   for (every pv in the list for the ppn) {
                           if (this pv is for this pmap/vaddr) {
                                   do housekeeping
                                   unlink/free the pv
                           }
                   }
           }
   
   The problem arose when we were running, say 8000 (or even 2000) apache or other processes 
   and one or all terminate. The list hanging off each pv array entry could have thousands of 
   entries.  We were continuously linearly searching each of these lists as we stepped through 
   the address space we were tearing down.  Because of the locks we hold, likely taking a cache 
   miss for each node,  and interrupt disabling for MP issues the system became completely 
   unresponsive for many seconds while we did this.
   
   Realizing that pve's are accessed in two distinct ways (linearly running the list by ppn 
   for operations like pmap_page_protect and finding and modifying/removing a single pve as 
   part of pmap_enter processing) has led to modifying the pve structures and databases.
   
   There are now two types of pve structures.  A "rooted" structure which is basically the 
   original structure accessed in an array by ppn, and a ''hashed'' structure accessed on a 
   hash list via a hash of [pmap, vaddr].  These have been designed with the two goals of 
   minimizing wired memory and making the lookup of a ppn faster.  Since a vast majority of 
   pages in the system are not aliased and hence represented by a single pv entry I've kept 
   the rooted entry size as small as possible because there is one of these dedicated for 
   every physical page of memory.  The hashed pve's are larger due to the addition of the hash 
   link and the ppn entry needed for matching while running the hash list to find the entry we 
   are looking for.  This way, only systems that have lots of aliasing (like 2000+ httpd procs) 
   will pay the extra memory price. Both structures have the same first three fields allowing 
   some simplification in the code.
   
   They have these shapes
   
   typedef struct pv_rooted_entry {
           queue_head_t qlink;
           vm_map_offset_t va;
           pmap_t          pmap;
   } *pv_rooted_entry_t;
   
   
   typedef struct pv_hashed_entry {
     queue_head_t qlink;
     vm_map_offset_t va;
     pmap_t        pmap;
     ppnum_t ppn;
     struct pv_hashed_entry *nexth;
   } *pv_hashed_entry_t;
   
   The main flow difference is that the code is now aware of the rooted entry and the hashed 
   entries.  Code that runs the pv list still starts with the rooted entry and then continues 
   down the qlink onto the hashed entries.  Code that is looking up a specific pv entry first 
   checks the rooted entry and then hashes and runs the hash list for the match. The hash list 
   lengths are much smaller than the original pv lists that contained all aliases for the specific ppn.
   
   */
   
   typedef struct pv_rooted_entry {     /* first three entries must match pv_hashed_entry_t */
           queue_head_t qlink;
           vm_map_offset_t va;             /* virtual address for mapping */
           pmap_t          pmap;           /* pmap where mapping lies */
   } *pv_rooted_entry_t;
   
   #define PV_ROOTED_ENTRY_NULL    ((pv_rooted_entry_t) 0)
   
   pv_rooted_entry_t       pv_head_table;          /* array of entries, one per page */
   
   typedef struct pv_hashed_entry {     /* first three entries must match pv_rooted_entry_t */
     queue_head_t qlink;
     vm_map_offset_t va;
     pmap_t        pmap;
     ppnum_t ppn;
     struct pv_hashed_entry *nexth;
   } *pv_hashed_entry_t;
   
   #define PV_HASHED_ENTRY_NULL ((pv_hashed_entry_t)0)
   
   #define NPVHASH 4095   /* MUST BE 2^N - 1 */
   pv_hashed_entry_t     *pv_hash_table;  /* hash lists */
   
   uint32_t npvhash = 0;
   
   /* #define PV_DEBUG 1   uncomment to enable some PV debugging code */
   #ifdef PV_DEBUG
   #define CHK_NPVHASH() if(0 == npvhash) panic("npvhash uninitialized");
   #else
   #define CHK_NPVHASH()
   #endif
   
   /*
    *      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_hashed_list_zone if it becomes empty.
    */
   pv_rooted_entry_t       pv_free_list = PV_ROOTED_ENTRY_NULL;            /* free list at SPLVM */
   pv_hashed_entry_t       pv_hashed_free_list = PV_HASHED_ENTRY_NULL;
   pv_hashed_entry_t      pv_hashed_kern_free_list = PV_HASHED_ENTRY_NULL;
   decl_simple_lock_data(,pv_hashed_free_list_lock)
   decl_simple_lock_data(,pv_hashed_kern_free_list_lock)
   decl_simple_lock_data(,pv_hash_table_lock)
   
   int pv_free_count = 0;
   int pv_hashed_free_count = 0;
   int pv_kern_free_count = 0;
   int pv_hashed_kern_free_count = 0;
   #define PV_HASHED_LOW_WATER_MARK 5000
   #define PV_HASHED_KERN_LOW_WATER_MARK 100
   #define PV_HASHED_ALLOC_CHUNK 2000
   #define PV_HASHED_KERN_ALLOC_CHUNK 50
   thread_call_t  mapping_adjust_call;
   static thread_call_data_t  mapping_adjust_call_data;
   uint32_t mappingrecurse = 0;
   
   #define PV_HASHED_ALLOC(pvh_e) { \
           simple_lock(&pv_hashed_free_list_lock); \
           if ((pvh_e = pv_hashed_free_list) != 0) { \
             pv_hashed_free_list = (pv_hashed_entry_t)pvh_e->qlink.next;   \
               pv_hashed_free_count--; \
               if (pv_hashed_free_count < PV_HASHED_LOW_WATER_MARK) \
                 if (hw_compare_and_store(0,1,(u_int *)&mappingrecurse)) \
                   thread_call_enter(mapping_adjust_call); \
           } \
           simple_unlock(&pv_hashed_free_list_lock); \
   }
   
   #define PV_HASHED_FREE_LIST(pvh_eh, pvh_et, pv_cnt) {   \
           simple_lock(&pv_hashed_free_list_lock); \
           pvh_et->qlink.next = (queue_entry_t)pv_hashed_free_list;        \
           pv_hashed_free_list = pvh_eh; \
           pv_hashed_free_count += pv_cnt; \
           simple_unlock(&pv_hashed_free_list_lock); \
   }
   
   #define PV_HASHED_KERN_ALLOC(pvh_e) { \
           simple_lock(&pv_hashed_kern_free_list_lock); \
           if ((pvh_e = pv_hashed_kern_free_list) != 0) { \
             pv_hashed_kern_free_list = (pv_hashed_entry_t)pvh_e->qlink.next;      \
               pv_hashed_kern_free_count--; \
               if (pv_hashed_kern_free_count < PV_HASHED_KERN_LOW_WATER_MARK) \
                 if (hw_compare_and_store(0,1,(u_int *)&mappingrecurse)) \
                   thread_call_enter(mapping_adjust_call); \
           } \
           simple_unlock(&pv_hashed_kern_free_list_lock); \
   }
   
   #define PV_HASHED_KERN_FREE_LIST(pvh_eh, pvh_et, pv_cnt) {       \
           simple_lock(&pv_hashed_kern_free_list_lock); \
           pvh_et->qlink.next = (queue_entry_t)pv_hashed_kern_free_list;   \
           pv_hashed_kern_free_list = pvh_eh; \
           pv_hashed_kern_free_count += pv_cnt; \
           simple_unlock(&pv_hashed_kern_free_list_lock); \
   }
   
   zone_t          pv_hashed_list_zone;    /* zone of pv_hashed_entry structures */
   
   static zone_t pdpt_zone;
   
   /*
    *      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)
   
   char    *pv_hash_lock_table;
   #define pv_hash_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.
    */
   boolean_t       pmap_initialized = FALSE;/* Has pmap_init completed? */
   
   static struct vm_object kptobj_object_store;
   static vm_object_t kptobj;
   
   /*
    *      Index into pv_head table, its lock bits, and the modify/reference and managed bits
    */
   
   #define pa_index(pa)    (i386_btop(pa))
   #define ppn_to_pai(ppn) ((int)ppn)
   
   #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)
   
   #define pvhashidx(pmap, va) (((uint32_t)pmap ^ ((uint32_t)((uint64_t)va >> PAGE_SHIFT) & 0xFFFFFFFF)) & npvhash)
   #define pvhash(idx)         (&pv_hash_table[idx])
   
   #define lock_hash_hash(hash)            bit_lock(hash, (void *)pv_hash_lock_table)
   #define unlock_hash_hash(hash)  bit_unlock(hash, (void *)pv_hash_lock_table)
   
   /*
    *      Array of physical page attribites for managed pages.
    *      One byte per physical page.
    */
   char    *pmap_phys_attributes;
   unsigned int    last_managed_page = 0;
   
   /*
    *      Physical page attributes.  Copy bits from PTE definition.
    */
   #define PHYS_MODIFIED   INTEL_PTE_MOD   /* page modified */
   #define PHYS_REFERENCED INTEL_PTE_REF   /* page referenced */
   #define PHYS_MANAGED    INTEL_PTE_VALID /* page is managed */
   
   /*
    *      Amount of virtual memory mapped by one
    *      page-directory entry.
    */
   #define PDE_MAPPED_SIZE         (pdetova(1))
   uint64_t pde_mapped_size;
   
   /*
    *      Locking and TLB invalidation
    */
   
   /*
    *      Locking Protocols: (changed 2/2007 JK)
    *
    *      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.
    *
    *      The system wide pmap lock has been removed. Now, paths take a lock
    *      on the pmap before changing its 'shape' and the reverse order lockers
    *      (coming in by phys ppn) take a lock on the corresponding pv and then
    *      retest to be sure nothing changed during the window before they locked
    *      and can then run up/down the pv lists holding the list lock. This also
    *      lets the pmap layer run (nearly completely) interrupt enabled, unlike
    *      previously.
    */
   
   
   /*
    * PV locking
    */
   
   #define LOCK_PVH(index)         {       \
       mp_disable_preemption();           \
       lock_pvh_pai(index);               \
   }
   
   #define UNLOCK_PVH(index)  {      \
       unlock_pvh_pai(index);        \
       mp_enable_preemption();       \
   }
   
   /*
    * PV hash locking
    */
   
   #define LOCK_PV_HASH(hash)         lock_hash_hash(hash)
   
   #define UNLOCK_PV_HASH(hash)       unlock_hash_hash(hash)
   
   #if     USLOCK_DEBUG
   extern int      max_lock_loops;
   #define LOOP_VAR                                                        \
           unsigned int    loop_count;                                     \
           loop_count = disable_serial_output ? max_lock_loops             \
                                           : max_lock_loops*100
   #define LOOP_CHECK(msg, pmap)                                           \
           if (--loop_count == 0) {                                        \
                   mp_disable_preemption();                                \
                   kprintf("%s: cpu %d pmap %x\n",                         \
                             msg, cpu_number(), pmap);                     \
                   Debugger("deadlock detection");                         \
                   mp_enable_preemption();                                 \
                   loop_count = max_lock_loops;                            \
           }
   #else   /* USLOCK_DEBUG */
   #define LOOP_VAR
   #define LOOP_CHECK(msg, pmap)
   #endif  /* USLOCK_DEBUG */
   
   unsigned pmap_memory_region_count;
   unsigned pmap_memory_region_current;
   
   pmap_memory_region_t pmap_memory_regions[PMAP_MEMORY_REGIONS_SIZE];
   
   /*
    *      Other useful macros.
    */
   #define current_pmap()          (vm_map_pmap(current_thread()->map))
   
   struct pmap     kernel_pmap_store;
   pmap_t          kernel_pmap;
   
   pd_entry_t    high_shared_pde;
   pd_entry_t    commpage64_pde;
   
   struct zone     *pmap_zone;             /* zone of pmap structures */
   
   int             pmap_debug = 0;         /* flag for debugging prints */
   
   unsigned int    inuse_ptepages_count = 0;
   
   addr64_t        kernel64_cr3;
   boolean_t       no_shared_cr3 = FALSE;  /* -no_shared_cr3 boot arg */
   
   
   /*
    *      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 char end;
   
   static int nkpt;
   
   pt_entry_t     *DMAP1, *DMAP2;
   caddr_t         DADDR1;
   caddr_t         DADDR2;
   
   static inline
   void pmap_pvh_unlink(pv_hashed_entry_t pv);
   
   /*
    * unlinks the pv_hashed_entry_t pvh from the singly linked hash chain.
    * properly deals with the anchor.
    * must be called with the hash locked, does not unlock it
    */
   
   static inline
   void pmap_pvh_unlink(pv_hashed_entry_t pvh)
   {
     pv_hashed_entry_t curh;
     pv_hashed_entry_t *pprevh;
     int pvhash_idx;
   
     CHK_NPVHASH();
     pvhash_idx = pvhashidx(pvh->pmap, pvh->va);
   
     pprevh = pvhash(pvhash_idx);
   
   #if PV_DEBUG
     if (NULL == *pprevh) panic("pvh_unlink null anchor"); /* JK DEBUG */
   #endif
     curh = *pprevh;
   
     while (PV_HASHED_ENTRY_NULL != curh) {
       if (pvh == curh)
         break;
       pprevh = &curh->nexth;
       curh = curh->nexth;
     }
     if (PV_HASHED_ENTRY_NULL == curh) panic("pmap_pvh_unlink no pvh");
     *pprevh = pvh->nexth;
     return;
   }
   
   /*
    * for legacy, returns the address of the pde entry.
    * for 64 bit, causes the pdpt page containing the pde entry to be mapped,
    * then returns the mapped address of the pde entry in that page
    */
   pd_entry_t *
   pmap_pde(pmap_t m, vm_map_offset_t v)
   {
     pd_entry_t *pde;
           if (!cpu_64bit || (m == kernel_pmap)) {
             pde = (&((m)->dirbase[(vm_offset_t)(v) >> PDESHIFT]));
           } else {
             assert(m);
             assert(ml_get_interrupts_enabled() == 0 || get_preemption_level() != 0);
             pde = pmap64_pde(m, v);
           }
           return pde;
   }
   
   
   /*
    * the single pml4 page per pmap is allocated at pmap create time and exists
    * for the duration of the pmap. we allocate this page in kernel vm (to save us one
    * level of page table dynamic mapping.
    * this returns the address of the requested pml4 entry in the top level page.
    */
   static inline
   pml4_entry_t *
   pmap64_pml4(pmap_t pmap, vm_map_offset_t vaddr)
   {
     return ((pml4_entry_t *)pmap->pm_hold + ((vm_offset_t)((vaddr>>PML4SHIFT)&(NPML4PG-1))));
   }
   
   /*
    * maps in the pml4 page, if any, containing the pdpt entry requested
    * and returns the address of the pdpt entry in that mapped page
    */
   pdpt_entry_t *
   pmap64_pdpt(pmap_t pmap, vm_map_offset_t vaddr)
   {
     pml4_entry_t newpf;
     pml4_entry_t *pml4;
     int i;
   
     assert(pmap);
     assert(ml_get_interrupts_enabled() == 0 || get_preemption_level() != 0);
     if ((vaddr > 0x00007FFFFFFFFFFFULL) && (vaddr < 0xFFFF800000000000ULL)) {
       return(0);
     }
   
     pml4 = pmap64_pml4(pmap, vaddr);
   
           if (pml4 && ((*pml4 & INTEL_PTE_VALID))) {
   
                   newpf = *pml4 & PG_FRAME;
   
   
                   for (i=PMAP_PDPT_FIRST_WINDOW; i < PMAP_PDPT_FIRST_WINDOW+PMAP_PDPT_NWINDOWS; i++) {
                     if (((*(current_cpu_datap()->cpu_pmap->mapwindow[i].prv_CMAP)) & PG_FRAME) == newpf) {
                     return((pdpt_entry_t *)(current_cpu_datap()->cpu_pmap->mapwindow[i].prv_CADDR) + 
                            ((vm_offset_t)((vaddr>>PDPTSHIFT)&(NPDPTPG-1))));
                     }
                   }
   
                     current_cpu_datap()->cpu_pmap->pdpt_window_index++;
                     if (current_cpu_datap()->cpu_pmap->pdpt_window_index > (PMAP_PDPT_FIRST_WINDOW+PMAP_PDPT_NWINDOWS-1))
                       current_cpu_datap()->cpu_pmap->pdpt_window_index = PMAP_PDPT_FIRST_WINDOW;
                     pmap_store_pte(
                                    (current_cpu_datap()->cpu_pmap->mapwindow[current_cpu_datap()->cpu_pmap->pdpt_window_index].prv_CMAP),
                                    newpf | INTEL_PTE_RW | INTEL_PTE_VALID);
                     invlpg((u_int)(current_cpu_datap()->cpu_pmap->mapwindow[current_cpu_datap()->cpu_pmap->pdpt_window_index].prv_CADDR));
                     return ((pdpt_entry_t *)(current_cpu_datap()->cpu_pmap->mapwindow[current_cpu_datap()->cpu_pmap->pdpt_window_index].prv_CADDR) +
                             ((vm_offset_t)((vaddr>>PDPTSHIFT)&(NPDPTPG-1))));
           }
   
           return (NULL);
   }
   
   /*
    * maps in the pdpt page, if any, containing the pde entry requested
    * and returns the address of the pde entry in that mapped page
    */
   pd_entry_t *
   pmap64_pde(pmap_t pmap, vm_map_offset_t vaddr)
   {
     pdpt_entry_t newpf;
     pdpt_entry_t *pdpt;
     int i;
   
     assert(pmap);
     assert(ml_get_interrupts_enabled() == 0 || get_preemption_level() != 0);
     if ((vaddr > 0x00007FFFFFFFFFFFULL) && (vaddr < 0xFFFF800000000000ULL)) {
       return(0);
     }
   
     /*  if (vaddr & (1ULL << 63)) panic("neg addr");*/
     pdpt = pmap64_pdpt(pmap, vaddr);
   
             if (pdpt && ((*pdpt & INTEL_PTE_VALID))) {
   
                   newpf = *pdpt & PG_FRAME;
   
                   for (i=PMAP_PDE_FIRST_WINDOW; i < PMAP_PDE_FIRST_WINDOW+PMAP_PDE_NWINDOWS; i++) {
                     if (((*(current_cpu_datap()->cpu_pmap->mapwindow[i].prv_CMAP)) & PG_FRAME) == newpf) {
                     return((pd_entry_t *)(current_cpu_datap()->cpu_pmap->mapwindow[i].prv_CADDR) + 
                            ((vm_offset_t)((vaddr>>PDSHIFT)&(NPDPG-1))));
                     }
                   }
   
                     current_cpu_datap()->cpu_pmap->pde_window_index++;
                     if (current_cpu_datap()->cpu_pmap->pde_window_index > (PMAP_PDE_FIRST_WINDOW+PMAP_PDE_NWINDOWS-1))
                       current_cpu_datap()->cpu_pmap->pde_window_index = PMAP_PDE_FIRST_WINDOW;
                     pmap_store_pte(
                                    (current_cpu_datap()->cpu_pmap->mapwindow[current_cpu_datap()->cpu_pmap->pde_window_index].prv_CMAP),
                                    newpf | INTEL_PTE_RW | INTEL_PTE_VALID);
                     invlpg((u_int)(current_cpu_datap()->cpu_pmap->mapwindow[current_cpu_datap()->cpu_pmap->pde_window_index].prv_CADDR));
                     return ((pd_entry_t *)(current_cpu_datap()->cpu_pmap->mapwindow[current_cpu_datap()->cpu_pmap->pde_window_index].prv_CADDR) +
                             ((vm_offset_t)((vaddr>>PDSHIFT)&(NPDPG-1))));
           }
   
           return (NULL);
   }
   
   /*
    * Because the page tables (top 3 levels) are mapped into per cpu windows,
    * callers must either disable interrupts or disable preemption before calling
    * one of the pte mapping routines (e.g. pmap_pte()) as the returned vaddr
    * is in one of those mapped windows and that cannot be allowed to change until
    * the caller is done using the returned pte pointer. When done, the caller
    * restores interrupts or preemption to its previous state after which point the
    * vaddr for the returned pte can no longer be used
    */
   
   
   /*
    * return address of mapped pte for vaddr va in pmap pmap.
    * must be called with pre-emption or interrupts disabled
    * if targeted pmap is not the kernel pmap
    * since we may be passing back a virtual address that is
    * associated with this cpu... pre-emption or interrupts
    * must remain disabled until the caller is done using
    * the pointer that was passed back .
    *
    * maps the pde page, if any, containing the pte in and returns
    * the address of the pte in that mapped page
    */
   pt_entry_t     *
   pmap_pte(pmap_t pmap, vm_map_offset_t vaddr)
   {
           pd_entry_t     *pde;
           pd_entry_t     newpf;
           int i;
   
           assert(pmap);
           pde = pmap_pde(pmap,vaddr);
   
           if (pde && ((*pde & INTEL_PTE_VALID))) {
              if (*pde & INTEL_PTE_PS)
                   return pde;
               if (pmap == kernel_pmap)
                   return (vtopte(vaddr)); /* compat kernel still has pte's mapped */
   #if TESTING
               if (ml_get_interrupts_enabled() && get_preemption_level() == 0)
                   panic("pmap_pte: unsafe call");
   #endif
                   assert(ml_get_interrupts_enabled() == 0 || get_preemption_level() != 0);
   
                   newpf = *pde & PG_FRAME;
   
                   for (i=PMAP_PTE_FIRST_WINDOW; i < PMAP_PTE_FIRST_WINDOW+PMAP_PTE_NWINDOWS; i++) {
                     if (((*(current_cpu_datap()->cpu_pmap->mapwindow[i].prv_CMAP)) & PG_FRAME) == newpf) {
                     return((pt_entry_t *)(current_cpu_datap()->cpu_pmap->mapwindow[i].prv_CADDR) + 
                            ((vm_offset_t)i386_btop(vaddr) & (NPTEPG-1)));
                     }
                   }
   
                     current_cpu_datap()->cpu_pmap->pte_window_index++;
                     if (current_cpu_datap()->cpu_pmap->pte_window_index > (PMAP_PTE_FIRST_WINDOW+PMAP_PTE_NWINDOWS-1))
                       current_cpu_datap()->cpu_pmap->pte_window_index = PMAP_PTE_FIRST_WINDOW;
                     pmap_store_pte(
                                    (current_cpu_datap()->cpu_pmap->mapwindow[current_cpu_datap()->cpu_pmap->pte_window_index].prv_CMAP),
                                    newpf | INTEL_PTE_RW | INTEL_PTE_VALID);
                     invlpg((u_int)(current_cpu_datap()->cpu_pmap->mapwindow[current_cpu_datap()->cpu_pmap->pte_window_index].prv_CADDR));
                     return ((pt_entry_t *)(current_cpu_datap()->cpu_pmap->mapwindow[current_cpu_datap()->cpu_pmap->pte_window_index].prv_CADDR) +
                             ((vm_offset_t)i386_btop(vaddr) & (NPTEPG-1)));
           }
   
           return(NULL);
   }
           
   
   /*
    *      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(
           vm_offset_t     virt,
           vm_map_offset_t start_addr,
           vm_map_offset_t end_addr,
           vm_prot_t       prot,
           unsigned int    flags)
   {
           int             ps;
   
           ps = PAGE_SIZE;
           while (start_addr < end_addr) {
                   pmap_enter(kernel_pmap, (vm_map_offset_t)virt,
                              (ppnum_t) i386_btop(start_addr), prot, flags, FALSE);
                   virt += ps;
                   start_addr += ps;
           }
           return(virt);
   }
   
   /*
    *      Back-door routine for mapping kernel VM at initialization.  
    *      Useful for mapping memory outside the range
    *      Sets no-cache, A, D.
    *      Otherwise like pmap_map.
    */
   vm_offset_t
   pmap_map_bd(
           vm_offset_t     virt,
           vm_map_offset_t start_addr,
           vm_map_offset_t end_addr,
           vm_prot_t       prot,
           unsigned int    flags)
   {
           pt_entry_t      template;
           pt_entry_t      *pte;
           spl_t           spl;
   
           template = pa_to_pte(start_addr)
                   | INTEL_PTE_REF
                   | INTEL_PTE_MOD
                   | INTEL_PTE_WIRED
                   | INTEL_PTE_VALID;
   
           if(flags & (VM_MEM_NOT_CACHEABLE | VM_WIMG_USE_DEFAULT)) {
               template |= INTEL_PTE_NCACHE;
               if(!(flags & (VM_MEM_GUARDED | VM_WIMG_USE_DEFAULT)))
                       template |= INTEL_PTE_PTA;
           }
   
           if (prot & VM_PROT_WRITE)
               template |= INTEL_PTE_WRITE;
   
   
           while (start_addr < end_addr) {
                   spl = splhigh();
                   pte = pmap_pte(kernel_pmap, (vm_map_offset_t)virt);
                   if (pte == PT_ENTRY_NULL) {
                           panic("pmap_map_bd: Invalid kernel address\n");
                   }
                   pmap_store_pte(pte, template);
                   splx(spl);
                   pte_increment_pa(template);
                   virt += PAGE_SIZE;
                   start_addr += PAGE_SIZE;
           } 
   
   
           flush_tlb();
           return(virt);
   }
   
   extern  char                    *first_avail;
   extern  vm_offset_t             virtual_avail, virtual_end;
   extern  pmap_paddr_t            avail_start, avail_end;
   
   void
   pmap_cpu_init(void)
   {
           /*
            * Here early in the life of a processor (from cpu_mode_init()).
            * If we're not in 64-bit mode, enable the global TLB feature.
            * Note: regardless of mode we continue to set the global attribute
            * bit in ptes for all (32-bit) global pages such as the commpage.
            */
           if (!cpu_64bit) {
                   set_cr4(get_cr4() | CR4_PGE);
           }
   
           /*
            * Initialize the per-cpu, TLB-related fields.
            */
           current_cpu_datap()->cpu_active_cr3 = kernel_pmap->pm_cr3;
           current_cpu_datap()->cpu_tlb_invalid = FALSE;
   }
   
   vm_offset_t
   pmap_high_shared_remap(enum high_fixed_addresses e, vm_offset_t va, int sz)
   {
     vm_offset_t ve = pmap_index_to_virt(e);
     pt_entry_t *ptep;
     pmap_paddr_t pa;
     int i;
     spl_t s;
   
     assert(0 == (va & PAGE_MASK));  /* expecting page aligned */
     s = splhigh();
     ptep = pmap_pte(kernel_pmap, (vm_map_offset_t)ve);
   
     for (i=0; i< sz; i++) {
       pa = (pmap_paddr_t) kvtophys(va);
       pmap_store_pte(ptep, (pa & PG_FRAME)
                                   | INTEL_PTE_VALID
                                   | INTEL_PTE_GLOBAL
                                   | INTEL_PTE_RW
                                   | INTEL_PTE_REF
                                   | INTEL_PTE_MOD);
       va+= PAGE_SIZE;
       ptep++;
     }
     splx(s);
     return ve;
   }
   
   vm_offset_t
   pmap_cpu_high_shared_remap(int cpu, enum high_cpu_types e, vm_offset_t va, int sz)
   { 
     enum high_fixed_addresses     a = e + HIGH_CPU_END * cpu;
     return pmap_high_shared_remap(HIGH_FIXED_CPUS_BEGIN + a, va, sz);
   }
   
   void pmap_init_high_shared(void);
   
   extern vm_offset_t gdtptr, idtptr;
   
   extern uint32_t low_intstack;
   
   extern struct fake_descriptor ldt_desc_pattern;
   extern struct fake_descriptor tss_desc_pattern;
   
   extern char hi_remap_text, hi_remap_etext;
   extern char t_zero_div;
   
   pt_entry_t *pte_unique_base;
   
   void
   pmap_init_high_shared(void)
   {
   
           vm_offset_t haddr;
           spl_t s;
   #if MACH_KDB
           struct i386_tss *ttss;
   #endif
   
           cpu_desc_index_t * cdi = &cpu_data_master.cpu_desc_index;
   
           kprintf("HIGH_MEM_BASE 0x%x fixed per-cpu begin 0x%x\n", 
                   HIGH_MEM_BASE,pmap_index_to_virt(HIGH_FIXED_CPUS_BEGIN));
           s = splhigh();
           pte_unique_base = pmap_pte(kernel_pmap, (vm_map_offset_t)pmap_index_to_virt(HIGH_FIXED_CPUS_BEGIN));
           splx(s);
   
           if (i386_btop(&hi_remap_etext - &hi_remap_text + 1) >
                                   HIGH_FIXED_TRAMPS_END - HIGH_FIXED_TRAMPS + 1)
                  panic("tramps too large");
          haddr = pmap_high_shared_remap(HIGH_FIXED_TRAMPS,
                                          (vm_offset_t) &hi_remap_text, 3);
          kprintf("tramp: 0x%x, ",haddr);
          /* map gdt up high and update ptr for reload */
          haddr = pmap_high_shared_remap(HIGH_FIXED_GDT,
                                          (vm_offset_t) master_gdt, 1);
          cdi->cdi_gdt.ptr = (void *)haddr;
          kprintf("GDT: 0x%x, ",haddr);
          /* map ldt up high */
          haddr = pmap_high_shared_remap(HIGH_FIXED_LDT_BEGIN,
                                          (vm_offset_t) master_ldt,
                                          HIGH_FIXED_LDT_END - HIGH_FIXED_LDT_BEGIN + 1);
          cdi->cdi_ldt = (struct fake_descriptor *)haddr;
          kprintf("LDT: 0x%x, ",haddr);
          /* put new ldt addr into gdt */
          struct fake_descriptor temp_fake_desc;
          temp_fake_desc = ldt_desc_pattern;
          temp_fake_desc.offset = (vm_offset_t) haddr;
          fix_desc(&temp_fake_desc, 1);
          
          *(struct fake_descriptor *) &master_gdt[sel_idx(KERNEL_LDT)] = temp_fake_desc;
          *(struct fake_descriptor *) &master_gdt[sel_idx(USER_LDT)] = temp_fake_desc;
  
          /* map idt up high */
          haddr = pmap_high_shared_remap(HIGH_FIXED_IDT,
                                          (vm_offset_t) master_idt, 1);
          cdi->cdi_idt.ptr = (void *)haddr;
          kprintf("IDT: 0x%x, ", haddr);
          /* remap ktss up high and put new high addr into gdt */
          haddr = pmap_high_shared_remap(HIGH_FIXED_KTSS,
                                          (vm_offset_t) &master_ktss, 1);
  
          temp_fake_desc = tss_desc_pattern;
          temp_fake_desc.offset = (vm_offset_t) haddr;
          fix_desc(&temp_fake_desc, 1);
          *(struct fake_descriptor *) &master_gdt[sel_idx(KERNEL_TSS)] = temp_fake_desc;
          kprintf("KTSS: 0x%x, ",haddr);
  #if MACH_KDB
          /* remap dbtss up high and put new high addr into gdt */
          haddr = pmap_high_shared_remap(HIGH_FIXED_DBTSS,
                                          (vm_offset_t) &master_dbtss, 1);
          temp_fake_desc = tss_desc_pattern;
          temp_fake_desc.offset = (vm_offset_t) haddr;
          fix_desc(&temp_fake_desc, 1);
          *(struct fake_descriptor *)&master_gdt[sel_idx(DEBUG_TSS)] = temp_fake_desc;
          ttss = (struct i386_tss *)haddr;
          kprintf("DBTSS: 0x%x, ",haddr);
  #endif  /* MACH_KDB */
  
          /* remap dftss up high and put new high addr into gdt */
          haddr = pmap_high_shared_remap(HIGH_FIXED_DFTSS,
                                          (vm_offset_t) &master_dftss, 1);
          temp_fake_desc = tss_desc_pattern;
          temp_fake_desc.offset = (vm_offset_t) haddr;
          fix_desc(&temp_fake_desc, 1);
          *(struct fake_descriptor *) &master_gdt[sel_idx(DF_TSS)] = temp_fake_desc;
          kprintf("DFTSS: 0x%x\n",haddr);
  
          /* remap mctss up high and put new high addr into gdt */
          haddr = pmap_high_shared_remap(HIGH_FIXED_DFTSS,
                                          (vm_offset_t) &master_mctss, 1);
          temp_fake_desc = tss_desc_pattern;
          temp_fake_desc.offset = (vm_offset_t) haddr;
          fix_desc(&temp_fake_desc, 1);
          *(struct fake_descriptor *) &master_gdt[sel_idx(MC_TSS)] = temp_fake_desc;
          kprintf("MCTSS: 0x%x\n",haddr);
  
          cpu_desc_load(&cpu_data_master);
  }
  
  
  /*
   *      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.
   */
  
  void
  pmap_bootstrap(
          __unused vm_offset_t    load_start,
          boolean_t               IA32e)
  {
          vm_offset_t     va;
          pt_entry_t      *pte;
          int i;
          pdpt_entry_t *pdpt;
          spl_t s;
  
          vm_last_addr = VM_MAX_KERNEL_ADDRESS;   /* Set the highest address
                                                   * known to VM */
          /*
           *      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;
          kernel_pmap->ref_count = 1;
          kernel_pmap->nx_enabled = FALSE;
          kernel_pmap->pm_task_map = TASK_MAP_32BIT;
          kernel_pmap->pm_obj = (vm_object_t) NULL;
          kernel_pmap->dirbase = (pd_entry_t *)((unsigned int)IdlePTD | KERNBASE);
          kernel_pmap->pdirbase = (pmap_paddr_t)((int)IdlePTD);
          pdpt = (pd_entry_t *)((unsigned int)IdlePDPT | KERNBASE );
          kernel_pmap->pm_pdpt = pdpt;
          kernel_pmap->pm_cr3 = (pmap_paddr_t)((int)IdlePDPT);
  
  
          va = (vm_offset_t)kernel_pmap->dirbase;
          /* setup self referential mapping(s) */
          for (i = 0; i< NPGPTD; i++, pdpt++) {
            pmap_paddr_t pa;
            pa = (pmap_paddr_t) kvtophys((vm_offset_t)(va + i386_ptob(i)));
            pmap_store_pte(
              (pd_entry_t *) (kernel_pmap->dirbase + PTDPTDI + i),
              (pa & PG_FRAME) | INTEL_PTE_VALID | INTEL_PTE_RW | INTEL_PTE_REF |
                INTEL_PTE_MOD | INTEL_PTE_WIRED) ;
            pmap_store_pte(pdpt, pa | INTEL_PTE_VALID);
          }
  
          cpu_64bit = IA32e;
          
          lo_kernel_cr3 = kernel_pmap->pm_cr3;
          current_cpu_datap()->cpu_kernel_cr3 = (addr64_t) kernel_pmap->pm_cr3;
  
          /* save the value we stuff into created pmaps to share the gdts etc */
          high_shared_pde = *pmap_pde(kernel_pmap, HIGH_MEM_BASE);
          /* make sure G bit is on for high shared pde entry */
          high_shared_pde |= INTEL_PTE_GLOBAL;
          s = splhigh();
          pmap_store_pte(pmap_pde(kernel_pmap, HIGH_MEM_BASE), high_shared_pde);
          splx(s);
  
          nkpt = NKPT;
          OSAddAtomic(NKPT, &inuse_ptepages_count);
  
          virtual_avail = (vm_offset_t)VADDR(KPTDI,0) + (vm_offset_t)first_avail;
          virtual_end = (vm_offset_t)(VM_MAX_KERNEL_ADDRESS);
  
          /*
           * Reserve some special page table entries/VA space for temporary
           * mapping of pages.
           */
  #define SYSMAP(c, p, v, n)      \
          v = (c)va; va += ((n)*INTEL_PGBYTES); p = pte; pte += (n)
  
          va = virtual_avail;
          pte = vtopte(va);
  
          for (i=0; i<PMAP_NWINDOWS; i++) {
              SYSMAP(caddr_t,
                     (current_cpu_datap()->cpu_pmap->mapwindow[i].prv_CMAP),
                     (current_cpu_datap()->cpu_pmap->mapwindow[i].prv_CADDR),
                     1);
              *current_cpu_datap()->cpu_pmap->mapwindow[i].prv_CMAP = 0;
          }
  
          /* DMAP user for debugger */
          SYSMAP(caddr_t, DMAP1, DADDR1, 1);
          SYSMAP(caddr_t, DMAP2, DADDR2, 1);  /* XXX temporary - can remove */
  
          virtual_avail = va;
  
          if (PE_parse_boot_argn("npvhash", &npvhash, sizeof (npvhash))) {
            if (0 != ((npvhash+1) & npvhash)) {
              kprintf("invalid hash %d, must be ((2^N)-1), using default %d\n",npvhash,NPVHASH);
              npvhash = NPVHASH;
            }
          } else {
            npvhash = NPVHASH;
          }
          printf("npvhash=%d\n",npvhash);
  
          simple_lock_init(&kernel_pmap->lock, 0);
          simple_lock_init(&pv_hashed_free_list_lock, 0);
          simple_lock_init(&pv_hashed_kern_free_list_lock, 0);
          simple_lock_init(&pv_hash_table_lock,0);
  
          pmap_init_high_shared();
  
          pde_mapped_size = PDE_MAPPED_SIZE;
  
          if (cpu_64bit) {
            pdpt_entry_t *ppdpt   = IdlePDPT;
            pdpt_entry_t *ppdpt64 = (pdpt_entry_t *)IdlePDPT64;
            pdpt_entry_t *ppml4   = (pdpt_entry_t *)IdlePML4;
            int istate = ml_set_interrupts_enabled(FALSE);
  
            /*
             * Clone a new 64-bit 3rd-level page table directory, IdlePML4,
             * with page bits set for the correct IA-32e operation and so that
             * the legacy-mode IdlePDPT is retained for slave processor start-up.
             * This is necessary due to the incompatible use of page bits between
             * 64-bit and legacy modes.
             */
            kernel_pmap->pm_cr3 = (pmap_paddr_t)((int)IdlePML4); /* setup in start.s for us */
            kernel_pmap->pm_pml4 = IdlePML4;
            kernel_pmap->pm_pdpt = (pd_entry_t *)
                                          ((unsigned int)IdlePDPT64 | KERNBASE );
  #define PAGE_BITS INTEL_PTE_VALID|INTEL_PTE_RW|INTEL_PTE_USER|INTEL_PTE_REF
            pmap_store_pte(kernel_pmap->pm_pml4,
                           (uint32_t)IdlePDPT64 | PAGE_BITS);
            pmap_store_pte((ppdpt64+0), *(ppdpt+0) | PAGE_BITS);
            pmap_store_pte((ppdpt64+1), *(ppdpt+1) | PAGE_BITS);
            pmap_store_pte((ppdpt64+2), *(ppdpt+2) | PAGE_BITS);
            pmap_store_pte((ppdpt64+3), *(ppdpt+3) | PAGE_BITS);
  
            /*
             * The kernel is also mapped in the uber-sapce at the 4GB starting
             * 0xFFFFFF80:00000000. This is the highest entry in the 4th-level.
             */
            pmap_store_pte((ppml4+KERNEL_UBER_PML4_INDEX), *(ppml4+0));
  
            kernel64_cr3 = (addr64_t) kernel_pmap->pm_cr3;
  
            /* Re-initialize descriptors and prepare to switch modes */
            cpu_desc_init64(&cpu_data_master);
            current_cpu_datap()->cpu_is64bit = TRUE;
            current_cpu_datap()->cpu_active_cr3 = kernel64_cr3;
  
            pde_mapped_size = 512*4096 ; 
  
            ml_set_interrupts_enabled(istate);
          }
  
          /* Sets 64-bit mode if required. */
          cpu_mode_init(&cpu_data_master);
          /* Update in-kernel CPUID information if we're now in 64-bit mode */
          if (IA32e)
                  cpuid_set_info();
  
          kernel_pmap->pm_hold = (vm_offset_t)kernel_pmap->pm_pml4;
  
          kprintf("Kernel virtual space from 0x%x to 0x%x.\n",
                          VADDR(KPTDI,0), virtual_end);
          printf("PAE enabled\n");
          if (cpu_64bit){
            printf("64 bit mode enabled\n");kprintf("64 bit mode enabled\n"); }
  
          kprintf("Available physical space from 0x%llx to 0x%llx\n",
                          avail_start, avail_end);
  
          /*
           * By default for 64-bit users loaded at 4GB, share kernel mapping.
           * But this may be overridden by the -no_shared_cr3 boot-arg.
           */
          if (PE_parse_boot_argn("-no_shared_cr3", &no_shared_cr3, sizeof (no_shared_cr3))) {
                  kprintf("Shared kernel address space disabled\n");
          }       
  
  #ifdef  PMAP_TRACES
          if (PE_parse_boot_argn("-pmap_trace", &pmap_trace, sizeof (pmap_trace))) {
                  kprintf("Kernel traces for pmap operations enabled\n");
          }       
  #endif  /* PMAP_TRACES */
  }
  
  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;
          vm_map_offset_t         vaddr;
          ppnum_t ppn;
  
          /*
           *      Allocate memory for the pv_head_table and its lock bits,
           *      the modify bit array, and the pte_page table.
           */
  
          /*
           * zero bias all these arrays now instead of off avail_start
           * so we cover all memory
           */
  
          npages = (long)i386_btop(avail_end);
          s = (vm_size_t) (sizeof(struct pv_rooted_entry) * npages
                           + (sizeof (struct pv_hashed_entry_t *) * (npvhash+1))
                           + pv_lock_table_size(npages)
                           + pv_hash_lock_table_size((npvhash+1))
                                  + npages);
  
          s = round_page(s);
          if (kernel_memory_allocate(kernel_map, &addr, s, 0,
                                     KMA_KOBJECT | KMA_PERMANENT)
              != KERN_SUCCESS)
                  panic("pmap_init");
  
          memset((char *)addr, 0, s);
  
  #if PV_DEBUG
          if (0 == npvhash) panic("npvhash not initialized");
  #endif
  
          /*
           *      Allocate the structures first to preserve word-alignment.
           */
          pv_head_table = (pv_rooted_entry_t) addr;
          addr = (vm_offset_t) (pv_head_table + npages);
  
          pv_hash_table = (pv_hashed_entry_t *)addr;
          addr = (vm_offset_t) (pv_hash_table + (npvhash + 1));
  
          pv_lock_table = (char *) addr;
          addr = (vm_offset_t) (pv_lock_table + pv_lock_table_size(npages));
  
          pv_hash_lock_table = (char *) addr;
          addr = (vm_offset_t) (pv_hash_lock_table + pv_hash_lock_table_size((npvhash+1)));
  
          pmap_phys_attributes = (char *) addr;
          {
                  unsigned int i;
                  unsigned int pn;
                  ppnum_t  last_pn;
                  pmap_memory_region_t *pmptr = pmap_memory_regions;
  
                  last_pn = (ppnum_t)i386_btop(avail_end);
  
                  for (i = 0; i < pmap_memory_region_count; i++, pmptr++) {
                          if (pmptr->type == kEfiConventionalMemory) {
  
                                  for (pn = pmptr->base; pn <= pmptr->end; pn++) {
                                          if (pn < last_pn) {
                                                  pmap_phys_attributes[pn] |= PHYS_MANAGED;
  
                                                  if (pn > last_managed_page)
                                                          last_managed_page = pn;
                                          }
                                  }
                          }
                  }
          }
  
          /*
           *      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_hashed_entry);
          pv_hashed_list_zone = zinit(s, 10000*s, 4096, "pv_list"); /* XXX */
          s = 63;
          pdpt_zone = zinit(s, 400*s, 4096, "pdpt"); /* XXX */
  
          kptobj = &kptobj_object_store;
          _vm_object_allocate((vm_object_size_t)(NPGPTD*NPTDPG), kptobj);
          kernel_pmap->pm_obj = kptobj;
  
          /* create pv entries for kernel pages mapped by low level
             startup code.  these have to exist so we can pmap_remove()
             e.g. kext pages from the middle of our addr space */
  
          vaddr = (vm_map_offset_t)0;
          for (ppn = 0; ppn < i386_btop(avail_start) ; ppn++ ) {
            pv_rooted_entry_t     pv_e;
  
            pv_e = pai_to_pvh(ppn);
            pv_e->va = vaddr;
            vaddr += PAGE_SIZE;
            pv_e->pmap = kernel_pmap;
            queue_init(&pv_e->qlink);
          }
  
          pmap_initialized = TRUE;
  
          /*
           *      Initialize pmap cache.
           */
          pmap_cache_list = PMAP_NULL;
          pmap_cache_count = 0;
          simple_lock_init(&pmap_cache_lock, 0);
  
          max_preemption_latency_tsc = tmrCvt((uint64_t)MAX_PREEMPTION_LATENCY_NS, tscFCvtn2t);
  
  }
  
  
  #define managed_page(x) ( (unsigned int)x <= last_managed_page && (pmap_phys_attributes[x] & PHYS_MANAGED) )
  
  /*
   * this function is only used for debugging fron the vm layer
   */
  boolean_t
  pmap_verify_free(
                   ppnum_t pn)
  {
          pv_rooted_entry_t       pv_h;
          int             pai;
          boolean_t       result;
  
          assert(pn != vm_page_fictitious_addr);
  
          if (!pmap_initialized)
                  return(TRUE);
  
          if (pn == vm_page_guard_addr)
                  return TRUE;
  
          pai = ppn_to_pai(pn);
          if (!managed_page(pai))
                  return(FALSE);
          pv_h = pai_to_pvh(pn);
          result = (pv_h->pmap == PMAP_NULL);
          return(result);
  }
  
  boolean_t
  pmap_is_empty(
         pmap_t          pmap,
         vm_map_offset_t va_start,
         vm_map_offset_t va_end)
  {
          vm_map_offset_t offset;
          ppnum_t         phys_page;
  
          if (pmap == PMAP_NULL) {
                  return TRUE;
          }
  
          /*
           * Check the resident page count
           * - if it's zero, the pmap is completely empty.
           * This short-circuit test prevents a virtual address scan which is
           * painfully slow for 64-bit spaces.
           * This assumes the count is correct
           * .. the debug kernel ought to be checking perhaps by page table walk.
           */
          if (pmap->stats.resident_count == 0)
                  return TRUE;
  
          for (offset = va_start;
               offset < va_end;
               offset += PAGE_SIZE_64) {
                  phys_page = pmap_find_phys(pmap, offset);
                  if (phys_page) {
                          if (pmap != kernel_pmap &&
                              pmap->pm_task_map == TASK_MAP_32BIT &&
                              offset >= HIGH_MEM_BASE) {
                                  /*
                                   * The "high_shared_pde" is used to share
                                   * the entire top-most 2MB of address space
                                   * between the kernel and all 32-bit tasks.
                                   * So none of this can be removed from 32-bit
                                   * tasks.
                                   * Let's pretend there's nothing up
                                   * there...
                                   */
                                  return TRUE;
                          }
                          kprintf("pmap_is_empty(%p,0x%llx,0x%llx): "
                                  "page %d at 0x%llx\n",
                                  pmap, va_start, va_end, phys_page, offset);
                          return FALSE;
                  }
          }
  
          return TRUE;
  }
  
  
  /*
   *      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_map_size_t       sz,
              boolean_t           is_64bit)
  {
          pmap_t                  p;
          int             i;
          vm_offset_t     va;
          vm_size_t       size;
          pdpt_entry_t    *pdpt;
          pml4_entry_t    *pml4p;
          pd_entry_t      *pdp;
          int template;
          spl_t s;
  
          PMAP_TRACE(PMAP_CODE(PMAP__CREATE) | DBG_FUNC_START,
                     (int) (sz>>32), (int) sz, (int) is_64bit, 0, 0);
  
          size = (vm_size_t) sz;
  
          /*
           *      A software use-only map doesn't even need a map.
           */
  
          if (size != 0) {
                  return(PMAP_NULL);
          }
  
          p = (pmap_t) zalloc(pmap_zone);
          if (PMAP_NULL == p)
                  panic("pmap_create zalloc");
  
          /* init counts now since we'll be bumping some */
          simple_lock_init(&p->lock, 0);
          p->stats.resident_count = 0;
          p->stats.resident_max = 0;
          p->stats.wired_count = 0;
          p->ref_count = 1;
          p->nx_enabled = 1;
          p->pm_shared = FALSE;
  
          assert(!is_64bit || cpu_64bit);
          p->pm_task_map = is_64bit ? TASK_MAP_64BIT : TASK_MAP_32BIT;;
  
          if (!cpu_64bit) {
                  /* legacy 32 bit setup */
                  /* in the legacy case the pdpt layer is hardwired to 4 entries and each
                   * entry covers 1GB of addr space */
                  if (KERN_SUCCESS != kmem_alloc_kobject(kernel_map, (vm_offset_t *)(&p->dirbase), NBPTD))
                          panic("pmap_create kmem_alloc_kobject");
                  p->pm_hold = (vm_offset_t)zalloc(pdpt_zone);
                  if ((vm_offset_t)NULL == p->pm_hold) {
                          panic("pdpt zalloc");
                  }
                  pdpt = (pdpt_entry_t *) (( p->pm_hold + 31) & ~31);
                  p->pm_cr3 = (pmap_paddr_t)kvtophys((vm_offset_t)pdpt);
                  if (NULL == (p->pm_obj = vm_object_allocate((vm_object_size_t)(NPGPTD*NPTDPG))))
                          panic("pmap_create vm_object_allocate");
  
                  memset((char *)p->dirbase, 0, NBPTD);
  
                  va = (vm_offset_t)p->dirbase;
                  p->pdirbase = kvtophys(va);
  
                  template = cpu_64bit ? INTEL_PTE_VALID|INTEL_PTE_RW|INTEL_PTE_USER|INTEL_PTE_REF : INTEL_PTE_VALID;
                  for (i = 0; i< NPGPTD; i++, pdpt++ ) {
                          pmap_paddr_t pa;
                          pa = (pmap_paddr_t) kvtophys((vm_offset_t)(va + i386_ptob(i)));
                          pmap_store_pte(pdpt, pa | template);
                  }
  
                  /* map the high shared pde */
                  s = splhigh();
                  pmap_store_pte(pmap_pde(p, HIGH_MEM_BASE), high_shared_pde);
                  splx(s);
  
          } else {
                  /* 64 bit setup  */
  
                  /* alloc the pml4 page in kernel vm */
                  if (KERN_SUCCESS != kmem_alloc_kobject(kernel_map, (vm_offset_t *)(&p->pm_hold), PAGE_SIZE))
                          panic("pmap_create kmem_alloc_kobject pml4");
  
                  memset((char *)p->pm_hold, 0, PAGE_SIZE);
                  p->pm_cr3 = (pmap_paddr_t)kvtophys((vm_offset_t)p->pm_hold);
  
                  OSAddAtomic(1,  &inuse_ptepages_count);
  
                  /* allocate the vm_objs to hold the pdpt, pde and pte pages */
  
                  if (NULL == (p->pm_obj_pml4 = vm_object_allocate((vm_object_size_t)(NPML4PGS))))
                          panic("pmap_create pdpt obj");
  
                  if (NULL == (p->pm_obj_pdpt = vm_object_allocate((vm_object_size_t)(NPDPTPGS))))
                          panic("pmap_create pdpt obj");
  
                  if (NULL == (p->pm_obj = vm_object_allocate((vm_object_size_t)(NPDEPGS))))
                          panic("pmap_create pte obj");
  
                  /* uber space points to uber mapped kernel */
                  s = splhigh();
                  pml4p = pmap64_pml4(p, 0ULL);
                  pmap_store_pte((pml4p+KERNEL_UBER_PML4_INDEX),*kernel_pmap->pm_pml4);
  
  
                  if (!is_64bit) {
                          while ((pdp = pmap64_pde(p, (uint64_t)HIGH_MEM_BASE)) == PD_ENTRY_NULL) {
                                  splx(s);
                                  pmap_expand_pdpt(p, (uint64_t)HIGH_MEM_BASE); /* need room for another pde entry */
                                  s = splhigh();
                          }
                          pmap_store_pte(pdp, high_shared_pde);
                  }
                  splx(s);
          }
  
          PMAP_TRACE(PMAP_CODE(PMAP__CREATE) | DBG_FUNC_START,
                     (int) p, is_64bit, 0, 0, 0);
  
          return(p);
  }
  
  /*
   * The following routines implement the shared address optmization for 64-bit
   * users with a 4GB page zero.
   *
   * pmap_set_4GB_pagezero()
   *      is called in the exec and fork paths to mirror the kernel's
   *      mapping in the bottom 4G of the user's pmap. The task mapping changes
   *      from TASK_MAP_64BIT to TASK_MAP_64BIT_SHARED. This routine returns
   *      without doing anything if the -no_shared_cr3 boot-arg is set.
   *
   * pmap_clear_4GB_pagezero()
   *      is called in the exec/exit paths to undo this mirror. The task mapping
   *      reverts to TASK_MAP_64BIT. In addition, we switch to the kernel's
   *      CR3 by calling pmap_load_kernel_cr3(). 
   *
   * pmap_load_kernel_cr3()
   *      loads cr3 with the kernel's page table. In addition to being called
   *      by pmap_clear_4GB_pagezero(), it is used both prior to teardown and
   *      when we go idle in the context of a shared map.
   *
   * Further notes on per-cpu data used:
   *
   *      cpu_kernel_cr3  is the cr3 for the kernel's pmap.
   *                      This is loaded in a trampoline on entering the kernel
   *                      from a 32-bit user (or non-shared-cr3 64-bit user).
   *      cpu_task_cr3    is the cr3 for the current thread.
   *                      This is loaded in a trampoline as we exit the kernel.
   *      cpu_active_cr3  reflects the cr3 currently loaded.
   *                      However, the low order bit is set when the
   *                      processor is idle or interrupts are disabled
   *                      while the system pmap lock is held. It is used by
   *                      tlb shoot-down.
   *      cpu_task_map    indicates whether the task cr3 belongs to
   *                      a 32-bit, a 64-bit or a 64-bit shared map.
   *                      The latter allows the avoidance of the cr3 load
   *                      on kernel entry and exit.
   *      cpu_tlb_invalid set TRUE when a tlb flush is requested.
   *                      If the cr3 is "inactive" (the cpu is idle or the
   *                      system-wide pmap lock is held) this not serviced by
   *                      an IPI but at time when the cr3 becomes "active".
   */ 
  
  void
  pmap_set_4GB_pagezero(pmap_t p)
  {
          pdpt_entry_t    *user_pdptp;
          pdpt_entry_t    *kern_pdptp;
  
          assert(p->pm_task_map != TASK_MAP_32BIT);
  
          /* Kernel-shared cr3 may be disabled by boot arg. */
          if (no_shared_cr3)
                  return;
  
          /*
           * Set the bottom 4 3rd-level pte's to be the kernel's.
           */
          PMAP_LOCK(p);
          while ((user_pdptp = pmap64_pdpt(p, 0x0)) == PDPT_ENTRY_NULL) {
                  PMAP_UNLOCK(p);
                  pmap_expand_pml4(p, 0x0);
                  PMAP_LOCK(p);
          }
          kern_pdptp = kernel_pmap->pm_pdpt;
          pmap_store_pte(user_pdptp+0, *(kern_pdptp+0));
          pmap_store_pte(user_pdptp+1, *(kern_pdptp+1));
          pmap_store_pte(user_pdptp+2, *(kern_pdptp+2));
          pmap_store_pte(user_pdptp+3, *(kern_pdptp+3));
          p->pm_task_map = TASK_MAP_64BIT_SHARED;
          PMAP_UNLOCK(p);
  }
  
  void
  pmap_clear_4GB_pagezero(pmap_t p)
  {
          pdpt_entry_t    *user_pdptp;
  
          if (p->pm_task_map != TASK_MAP_64BIT_SHARED)
                  return;
  
          PMAP_LOCK(p);
  
          p->pm_task_map = TASK_MAP_64BIT;
  
          pmap_load_kernel_cr3();
  
          user_pdptp = pmap64_pdpt(p, 0x0);
          pmap_store_pte(user_pdptp+0, 0);
          pmap_store_pte(user_pdptp+1, 0);
          pmap_store_pte(user_pdptp+2, 0);
          pmap_store_pte(user_pdptp+3, 0);
  
          PMAP_UNLOCK(p);
  }
  
  void
  pmap_load_kernel_cr3(void)
  {
          uint64_t        kernel_cr3;
  
          assert(ml_get_interrupts_enabled() == 0 || get_preemption_level() != 0);
  
          /*
           * Reload cr3 with the true kernel cr3.
           */
          kernel_cr3 = current_cpu_datap()->cpu_kernel_cr3;
          set64_cr3(kernel_cr3);
          current_cpu_datap()->cpu_active_cr3 = kernel_cr3;
          current_cpu_datap()->cpu_tlb_invalid = FALSE;
          __asm__ volatile("mfence");
  }
  
  /*
   *      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 int            c;
  
          if (p == PMAP_NULL)
                  return;
  
          PMAP_TRACE(PMAP_CODE(PMAP__DESTROY) | DBG_FUNC_START,
                     (int) p, 0, 0, 0, 0);
  
          PMAP_LOCK(p);
  
          c = --p->ref_count;
  
          if (c == 0) {
                  /* 
                   * 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:
                   */
                  PMAP_UPDATE_TLBS(p,
                                   0x0ULL,
                                   0xFFFFFFFFFFFFF000ULL);
          }
  
          PMAP_UNLOCK(p);
  
          if (c != 0) {
                  PMAP_TRACE(PMAP_CODE(PMAP__DESTROY) | DBG_FUNC_END,
                             (int) p, 1, 0, 0, 0);
                  return; /* still in use */
          }
  
          /*
           *      Free the memory maps, then the
           *      pmap structure.
           */
          if (!cpu_64bit) {
                  OSAddAtomic(-p->pm_obj->resident_page_count,  &inuse_ptepages_count);
  
                  kmem_free(kernel_map, (vm_offset_t)p->dirbase, NBPTD);
                  zfree(pdpt_zone, (void *)p->pm_hold);
  
                  vm_object_deallocate(p->pm_obj);
          } else {
                  /* 64 bit */
                  int inuse_ptepages = 0;
  
                  /* free 64 bit mode structs */
                  inuse_ptepages++;
                  kmem_free(kernel_map, (vm_offset_t)p->pm_hold, PAGE_SIZE);
  
                  inuse_ptepages += p->pm_obj_pml4->resident_page_count;
                  vm_object_deallocate(p->pm_obj_pml4);
  
                  inuse_ptepages += p->pm_obj_pdpt->resident_page_count;
                  vm_object_deallocate(p->pm_obj_pdpt);
  
                  inuse_ptepages += p->pm_obj->resident_page_count;
                  vm_object_deallocate(p->pm_obj);
  
                  OSAddAtomic(-inuse_ptepages,  &inuse_ptepages_count);
          }
          zfree(pmap_zone, p);
  
          PMAP_TRACE(PMAP_CODE(PMAP__DESTROY) | DBG_FUNC_END,
                     0, 0, 0, 0, 0);
  
  }
  
  /*
   *      Add a reference to the specified pmap.
   */
  
  void
  pmap_reference(
          register pmap_t p)
  {
  
          if (p != PMAP_NULL) {
                  PMAP_LOCK(p);
                  p->ref_count++;
                  PMAP_UNLOCK(p);;
          }
  }
  
  /*
   *      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.
   */
  
  void
  pmap_remove_range(
          pmap_t                  pmap,
          vm_map_offset_t         start_vaddr,
          pt_entry_t              *spte,
          pt_entry_t              *epte)
  {
          register pt_entry_t     *cpte;
          pv_hashed_entry_t       pvh_et = PV_HASHED_ENTRY_NULL;
          pv_hashed_entry_t       pvh_eh = PV_HASHED_ENTRY_NULL;
          pv_hashed_entry_t       pvh_e;
          int                     pvh_cnt = 0;
          int                     num_removed, num_unwired, num_found;
          int                     pai;
          pmap_paddr_t            pa;
          vm_map_offset_t         vaddr;
          int                     pvhash_idx;
          uint32_t                pv_cnt;
  
          num_removed = 0;
          num_unwired = 0;
          num_found   = 0;
  
          if (pmap != kernel_pmap &&
              pmap->pm_task_map == TASK_MAP_32BIT &&
              start_vaddr >= HIGH_MEM_BASE) {
                  /*
                   * The range is in the "high_shared_pde" which is shared
                   * between the kernel and all 32-bit tasks.  It holds
                   * the 32-bit commpage but also the trampolines, GDT, etc...
                   * so we can't let user tasks remove anything from it.
                   */
                  return;
          }
  
          /* invalidate the PTEs first to "freeze" them */
          for (cpte = spte, vaddr = start_vaddr;
               cpte < epte;
               cpte++, vaddr += PAGE_SIZE_64) {
  
              pa = pte_to_pa(*cpte);
              if (pa == 0)
                  continue;
              num_found++;
  
              if (iswired(*cpte))
                  num_unwired++;
  
              pai = pa_index(pa);
  
              if (!managed_page(pai)) {
                  /*
                   *      Outside range of managed physical memory.
                   *      Just remove the mappings.
                   */
                  pmap_store_pte(cpte, 0);
                  continue;
              }
  
              /* invalidate the PTE */ 
              pmap_update_pte(cpte, *cpte, (*cpte & ~INTEL_PTE_VALID));
          }
  
          if (num_found == 0) {
                  /* nothing was changed: we're done */
                  goto update_counts;
          }
  
          /* propagate the invalidates to other CPUs */
  
          PMAP_UPDATE_TLBS(pmap, start_vaddr, vaddr);
  
          for (cpte = spte, vaddr = start_vaddr;
               cpte < epte;
               cpte++, vaddr += PAGE_SIZE_64) {
  
              pa = pte_to_pa(*cpte);
              if (pa == 0)
                  continue;
  
              pai = pa_index(pa);
  
              LOCK_PVH(pai);
  
              pa = pte_to_pa(*cpte);
              if (pa == 0) {
                UNLOCK_PVH(pai);
                continue;
              }
                
              num_removed++;
  
              /*
               *  Get the modify and reference bits, then
               *  nuke the entry in the page table
               */
              /* remember reference and change */
              pmap_phys_attributes[pai] |=
                      (char)(*cpte & (PHYS_MODIFIED | PHYS_REFERENCED));
              /* completely invalidate the PTE */
              pmap_store_pte(cpte, 0);
  
              /*
               *  Remove the mapping from the pvlist for
               *  this physical page.
               */
              {
                pv_rooted_entry_t pv_h;
                pv_hashed_entry_t *pprevh;
                ppnum_t ppn = (ppnum_t)pai;
  
                  pv_h = pai_to_pvh(pai);
                  pvh_e = PV_HASHED_ENTRY_NULL;
                  if (pv_h->pmap == PMAP_NULL)
                      panic("pmap_remove_range: null pv_list!");
  
                  if (pv_h->va == vaddr && pv_h->pmap == pmap) { /* rooted or not */
                      /*
                       * Header is the pv_rooted_entry. We can't free that. If there is a queued
                       * entry after this one we remove that
                       * from the ppn queue, we remove it from the hash chain
                       * and copy it to the rooted entry. Then free it instead.
                       */
  
                    pvh_e = (pv_hashed_entry_t)queue_next(&pv_h->qlink);
                    if (pv_h != (pv_rooted_entry_t)pvh_e) {  /* any queued after rooted? */
                      CHK_NPVHASH();
                      pvhash_idx = pvhashidx(pvh_e->pmap,pvh_e->va);
                      LOCK_PV_HASH(pvhash_idx);
                      remque(&pvh_e->qlink);
                      {
                        pprevh = pvhash(pvhash_idx);
                        if (PV_HASHED_ENTRY_NULL == *pprevh) {
                          panic("pmap_remove_range empty hash removing rooted pv");
                        }
                      }
                      pmap_pvh_unlink(pvh_e);
                      UNLOCK_PV_HASH(pvhash_idx);
                      pv_h->pmap = pvh_e->pmap;
                      pv_h->va = pvh_e->va;   /* dispose of pvh_e */
                    } else {  /* none queued after rooted */
                      pv_h->pmap = PMAP_NULL;
                      pvh_e = PV_HASHED_ENTRY_NULL;
                    }   /* any queued after rooted */
  
                  } else { /* rooted or not */
                    /* not removing rooted pv. find it on hash chain, remove from ppn queue and
                     * hash chain and free it */
                    CHK_NPVHASH();
                    pvhash_idx = pvhashidx(pmap,vaddr);
                    LOCK_PV_HASH(pvhash_idx);
                    pprevh = pvhash(pvhash_idx);
                    if (PV_HASHED_ENTRY_NULL == *pprevh) {
                      panic("pmap_remove_range empty hash removing hashed pv");
                      }
                    pvh_e = *pprevh;
                    pmap_pv_hashlist_walks++;
                    pv_cnt = 0;
                    while (PV_HASHED_ENTRY_NULL != pvh_e) {
                          pv_cnt++;
                          if (pvh_e->pmap == pmap && pvh_e->va == vaddr && pvh_e->ppn == ppn) break;
                          pprevh = &pvh_e->nexth;
                          pvh_e = pvh_e->nexth;
                    }
                    pmap_pv_hashlist_cnts += pv_cnt;
                    if (pmap_pv_hashlist_max < pv_cnt) pmap_pv_hashlist_max = pv_cnt;
                    if (PV_HASHED_ENTRY_NULL == pvh_e) panic("pmap_remove_range pv not on hash");
                    *pprevh = pvh_e->nexth;
                    remque(&pvh_e->qlink);
                    UNLOCK_PV_HASH(pvhash_idx);
  
                  } /* rooted or not */
  
                  UNLOCK_PVH(pai);
  
                  if (pvh_e != PV_HASHED_ENTRY_NULL) {
                    pvh_e->qlink.next = (queue_entry_t)pvh_eh;
                    pvh_eh = pvh_e;
  
                    if (pvh_et == PV_HASHED_ENTRY_NULL) {
                      pvh_et = pvh_e;
                    }
  
                    pvh_cnt++;
                  }
  
              } /* removing mappings for this phy page */
          } /* for loop */
          
          if (pvh_eh != PV_HASHED_ENTRY_NULL) {
              PV_HASHED_FREE_LIST(pvh_eh, pvh_et, pvh_cnt);
          }
  
  update_counts:
          /*
           *      Update the counts
           */
  #if TESTING
          if (pmap->stats.resident_count < num_removed)
                  panic("pmap_remove_range: resident_count");
  #endif
          assert(pmap->stats.resident_count >= num_removed);
          OSAddAtomic(-num_removed,  &pmap->stats.resident_count);
  
  #if TESTING
          if (pmap->stats.wired_count < num_unwired)
                  panic("pmap_remove_range: wired_count");
  #endif
          assert(pmap->stats.wired_count >= num_unwired);
          OSAddAtomic(-num_unwired,  &pmap->stats.wired_count);
  
          return;
  }
  
  /*
   *      Remove phys addr if mapped in specified map
   *
   */
  void
  pmap_remove_some_phys(
          __unused pmap_t         map,
          __unused ppnum_t         pn)
  {
  
  /* 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,
          addr64_t        s64,
          addr64_t        e64)
  {
          pt_entry_t      *pde;
          pt_entry_t      *spte, *epte;
          addr64_t        l64;
          addr64_t        orig_s64;
          uint64_t        deadline;
  
          pmap_intr_assert();
  
          if (map == PMAP_NULL || s64 == e64)
                  return;
   
          PMAP_TRACE(PMAP_CODE(PMAP__REMOVE) | DBG_FUNC_START,
                     (int) map,
                     (int) (s64>>32), (int) s64,
                     (int) (e64>>32), (int) e64);
  
          PMAP_LOCK(map);
  
  #if 0
          /*
           * Check that address range in the kernel does not overlap the stacks.
           * We initialize local static min/max variables once to avoid making
           * 2 function calls for every remove. Note also that these functions
           * both return 0 before kernel stacks have been initialized, and hence
           * the panic is not triggered in this case.
           */
          if (map == kernel_pmap) {
                  static vm_offset_t      kernel_stack_min = 0;
                  static vm_offset_t      kernel_stack_max = 0;
  
                  if (kernel_stack_min == 0) {
                          kernel_stack_min = min_valid_stack_address();
                          kernel_stack_max = max_valid_stack_address();
                  }
                  if  ((kernel_stack_min <= s64 && s64 <  kernel_stack_max) ||
                       (kernel_stack_min <  e64 && e64 <= kernel_stack_max))
                          panic("pmap_remove() attempted in kernel stack");
          }
  #else
  
          /*
           * The values of kernel_stack_min and kernel_stack_max are no longer
           * relevant now that we allocate kernel stacks anywhere in the kernel map,
           * so the old code above no longer applies.  If we wanted to check that
           * we weren't removing a mapping of a page in a kernel stack we'd have to
           * mark the PTE with an unused bit and check that here.
           */
  
  #endif
  
          deadline = rdtsc64() + max_preemption_latency_tsc;
  
          orig_s64 = s64;
  
          while (s64 < e64) {
              l64 = (s64 + pde_mapped_size) & ~(pde_mapped_size-1);
              if (l64 > e64)
                  l64 = e64;
              pde = pmap_pde(map, s64);
  
              if (pde && (*pde & INTEL_PTE_VALID)) {
                  spte = (pt_entry_t *)pmap_pte(map, (s64 & ~(pde_mapped_size-1)));
                  spte = &spte[ptenum(s64)];
                  epte = &spte[intel_btop(l64-s64)];
  
                  pmap_remove_range(map, s64, spte, epte);
              }
              s64 = l64;
              pde++;
  
              if (s64 < e64 && rdtsc64() >= deadline) {
                PMAP_UNLOCK(map)
                  PMAP_LOCK(map)
  
                deadline = rdtsc64() + max_preemption_latency_tsc;
              }
  
          }
  
          PMAP_UNLOCK(map);
  
          PMAP_TRACE(PMAP_CODE(PMAP__REMOVE) | DBG_FUNC_END,
                     (int) map, 0, 0, 0, 0);
  
  }
  
  /*
   *      Routine:        pmap_page_protect
   *
   *      Function:
   *              Lower the permission for all mappings to a given
   *              page.
   */
  void
  pmap_page_protect(
          ppnum_t         pn,
          vm_prot_t       prot)
  {
          pv_hashed_entry_t               pvh_eh = PV_HASHED_ENTRY_NULL;
          pv_hashed_entry_t               pvh_et = PV_HASHED_ENTRY_NULL;
          pv_hashed_entry_t       nexth;
          int                     pvh_cnt = 0;
          pv_rooted_entry_t               pv_h;
          pv_rooted_entry_t               pv_e;
          pv_hashed_entry_t       pvh_e;
          pt_entry_t              *pte;
          int                     pai;
          register pmap_t         pmap;
          boolean_t               remove;
          int                     pvhash_idx;
  
          pmap_intr_assert();
          assert(pn != vm_page_fictitious_addr);
          if (pn == vm_page_guard_addr)
                  return;
  
          pai = ppn_to_pai(pn);
  
          if (!managed_page(pai)) {
              /*
               *  Not a managed page.
               */
              return;
          }
  
          PMAP_TRACE(PMAP_CODE(PMAP__PAGE_PROTECT) | DBG_FUNC_START,
                     (int) pn, (int) prot, 0, 0, 0);
  
          /*
           * 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;
          }
  
          pv_h = pai_to_pvh(pai);
  
          LOCK_PVH(pai);
  
  
          /*
           * Walk down PV list, changing or removing all mappings.
           */
          if (pv_h->pmap != PMAP_NULL) {
  
              pv_e = pv_h;
              pvh_e = (pv_hashed_entry_t)pv_e; /* cheat */
  
              do {
                  register vm_map_offset_t vaddr;
                  pmap = pv_e->pmap;
  
                  vaddr = pv_e->va;
                  pte = pmap_pte(pmap, vaddr);
                  
                  if (0 == pte) {
                          panic("pmap_page_protect: Missing PTE, pmap: %p, pn: 0x%x vaddr: 0x%llx, prot: %d kernel_pmap: %p", pmap, pn, vaddr, prot, kernel_pmap);
                  }
  
                  nexth = (pv_hashed_entry_t)queue_next(&pvh_e->qlink);  /* if there is one */
  
                  /*
                   * 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.
                       */
                      pmap_update_pte(pte, *pte, (*pte & ~INTEL_PTE_VALID));
  
                      PMAP_UPDATE_TLBS(pmap, vaddr, vaddr + PAGE_SIZE);
  
                      pmap_phys_attributes[pai] |= *pte & (PHYS_MODIFIED|PHYS_REFERENCED);
  
                      pmap_store_pte(pte, 0);
  
  #if TESTING
                      if (pmap->stats.resident_count < 1)
                          panic("pmap_page_protect: resident_count");
  #endif
                      assert(pmap->stats.resident_count >= 1);
                      OSAddAtomic(-1,  &pmap->stats.resident_count);
  
                      /*
                       * Deal with the pv_rooted_entry.
                       */
  
                      if (pv_e == pv_h) {
                          /*
                           * Fix up head later.
                           */
                          pv_h->pmap = PMAP_NULL;
                      }
                      else {
                          /*
                           * Delete this entry.
                           */
                        CHK_NPVHASH();
                        pvhash_idx = pvhashidx(pvh_e->pmap,pvh_e->va);
                        LOCK_PV_HASH(pvhash_idx);
                        remque(&pvh_e->qlink);
                        pmap_pvh_unlink(pvh_e);
                        UNLOCK_PV_HASH(pvhash_idx);
  
                        pvh_e->qlink.next = (queue_entry_t)pvh_eh;
                          pvh_eh = pvh_e;
  
                          if (pvh_et == PV_HASHED_ENTRY_NULL)
                              pvh_et = pvh_e;
                          pvh_cnt++;
                      }
                  } else {
                      /*
                       * Write-protect.
                       */
                      pmap_update_pte(pte, *pte, (*pte & ~INTEL_PTE_WRITE));
                      PMAP_UPDATE_TLBS(pmap, vaddr, vaddr + PAGE_SIZE);
                  }
  
                  pvh_e = nexth;
              } while ((pv_e = (pv_rooted_entry_t)nexth) != pv_h);
  
  
              /*
               * If pv_head mapping was removed, fix it up.
               */
  
              if (pv_h->pmap == PMAP_NULL) {
                pvh_e = (pv_hashed_entry_t)queue_next(&pv_h->qlink);
  
                if (pvh_e != (pv_hashed_entry_t)pv_h) {
                  CHK_NPVHASH();
                  pvhash_idx = pvhashidx(pvh_e->pmap,pvh_e->va);
                  LOCK_PV_HASH(pvhash_idx);
                  remque(&pvh_e->qlink);
                  pmap_pvh_unlink(pvh_e);
                  UNLOCK_PV_HASH(pvhash_idx);
                    pv_h->pmap = pvh_e->pmap;
                    pv_h->va = pvh_e->va;
                    pvh_e->qlink.next = (queue_entry_t)pvh_eh;
                      pvh_eh = pvh_e;
  
                      if (pvh_et == PV_HASHED_ENTRY_NULL)
                          pvh_et = pvh_e;
                      pvh_cnt++;
                  }
              }
          }
          if (pvh_eh != PV_HASHED_ENTRY_NULL) {
              PV_HASHED_FREE_LIST(pvh_eh, pvh_et, pvh_cnt);
          }
  
          UNLOCK_PVH(pai);
  
          PMAP_TRACE(PMAP_CODE(PMAP__PAGE_PROTECT) | DBG_FUNC_END,
                     0, 0, 0, 0, 0);
  
  }
  
  
  /*
   *      Routine:
   *              pmap_disconnect
   *
   *      Function:
   *              Disconnect all mappings for this page and return reference and change status
   *              in generic format.
   *
   */
  unsigned int pmap_disconnect(
          ppnum_t pa)
  {
          pmap_page_protect(pa, 0);                       /* disconnect the page */
          return (pmap_get_refmod(pa));                   /* return ref/chg status */
  }
  
  /*
   *      Set the physical protection on the
   *      specified range of this map as requested.
   *      Will not increase permissions.
   */
  void
  pmap_protect(
          pmap_t          map,
          vm_map_offset_t sva,
          vm_map_offset_t eva,
          vm_prot_t       prot)
  {
          register pt_entry_t     *pde;
          register pt_entry_t     *spte, *epte;
          vm_map_offset_t         lva;
          vm_map_offset_t         orig_sva;
          boolean_t       set_NX;
          int             num_found = 0;
  
          pmap_intr_assert();
  
          if (map == PMAP_NULL)
                  return;
  
          if (prot == VM_PROT_NONE) {
                  pmap_remove(map, sva, eva);
                  return;
          }
  
          PMAP_TRACE(PMAP_CODE(PMAP__PROTECT) | DBG_FUNC_START,
                     (int) map,
                     (int) (sva>>32), (int) sva,
                     (int) (eva>>32), (int) eva);
  
          if ( (prot & VM_PROT_EXECUTE) || !nx_enabled || !map->nx_enabled )
                  set_NX = FALSE;
          else
                  set_NX = TRUE;
  
          PMAP_LOCK(map);
  
          orig_sva = sva;
          while (sva < eva) {
              lva = (sva + pde_mapped_size) & ~(pde_mapped_size-1);
              if (lva > eva)
                  lva = eva;
              pde = pmap_pde(map, sva);
              if (pde && (*pde & INTEL_PTE_VALID)) {
                  spte = (pt_entry_t *)pmap_pte(map, (sva & ~(pde_mapped_size-1)));
                  spte = &spte[ptenum(sva)];
                  epte = &spte[intel_btop(lva-sva)];
  
                  while (spte < epte) {
  
                      if (*spte & INTEL_PTE_VALID) {
                        
                          if (prot & VM_PROT_WRITE)
                              pmap_update_pte(spte, *spte, (*spte | INTEL_PTE_WRITE));
                          else
                              pmap_update_pte(spte, *spte, (*spte & ~INTEL_PTE_WRITE));
  
                          if (set_NX == TRUE)
                              pmap_update_pte(spte, *spte, (*spte | INTEL_PTE_NX));
                          else
                              pmap_update_pte(spte, *spte, (*spte & ~INTEL_PTE_NX));
  
                          num_found++;
                      }
                      spte++;
                  }
              }
              sva = lva;
          }
          if (num_found)
              PMAP_UPDATE_TLBS(map, orig_sva, eva);
  
          PMAP_UNLOCK(map);
  
          PMAP_TRACE(PMAP_CODE(PMAP__PROTECT) | DBG_FUNC_END,
                     0, 0, 0, 0, 0);
  
  }
  
  /* Map a (possibly) autogenned block */
  void
  pmap_map_block(
          pmap_t          pmap, 
          addr64_t        va,
          ppnum_t         pa,
          uint32_t        size,
          vm_prot_t       prot,
          int             attr,
          __unused unsigned int   flags)
  {
      uint32_t page;
  
      for (page = 0; page < size; page++) {
          pmap_enter(pmap, va, pa, prot, attr, TRUE);
          va += PAGE_SIZE;
          pa++;
      }
  }
  
  
  /*
   *      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_map_offset_t         vaddr,
          ppnum_t                 pn,
          vm_prot_t               prot,
          unsigned int            flags,
          boolean_t               wired)
  {
          register pt_entry_t     *pte;
          register pv_rooted_entry_t      pv_h;
          register int            pai;
          pv_hashed_entry_t               pvh_e;
          pv_hashed_entry_t               pvh_new;
          pv_hashed_entry_t       *hashp;
          pt_entry_t              template;
          pmap_paddr_t            old_pa;
          pmap_paddr_t             pa = (pmap_paddr_t)i386_ptob(pn);
          boolean_t               need_tlbflush = FALSE;
          boolean_t               set_NX;
          char                    oattr;
          int                     pvhash_idx;
          uint32_t                pv_cnt;
          boolean_t               old_pa_locked;
  
          pmap_intr_assert();
          assert(pn != vm_page_fictitious_addr);
          if (pmap_debug)
                  printf("pmap(%qx, %x)\n", vaddr, pn);
          if (pmap == PMAP_NULL)
                  return;
          if (pn == vm_page_guard_addr)
                  return;
  
          PMAP_TRACE(PMAP_CODE(PMAP__ENTER) | DBG_FUNC_START,
                     (int) pmap,
                     (int) (vaddr>>32), (int) vaddr,
                     (int) pn, prot);
  
          if ( (prot & VM_PROT_EXECUTE) || !nx_enabled || !pmap->nx_enabled )
                  set_NX = FALSE;
          else
                  set_NX = TRUE;
          
          /*
           *      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).
           */
  
          pvh_new = PV_HASHED_ENTRY_NULL;
  Retry:
          pvh_e = PV_HASHED_ENTRY_NULL;
  
          PMAP_LOCK(pmap);
  
          /*
           *      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, vaddr)) == PT_ENTRY_NULL) {
                  /*
                   *      Must unlock to expand the pmap.
                   */
                  PMAP_UNLOCK(pmap);
                  pmap_expand(pmap, vaddr); /* going to grow pde level page(s) */
                  PMAP_LOCK(pmap);
          }
  
          old_pa = pte_to_pa(*pte);
          pai = pa_index(old_pa);
          old_pa_locked = FALSE;
  
          /*
           * if we have a previous managed page, lock the pv entry now. after
           * we lock it, check to see if someone beat us to the lock and if so
           * drop the lock
           */
  
          if ((0 != old_pa) && managed_page(pai)) {
            LOCK_PVH(pai);
            old_pa_locked = TRUE;
            old_pa = pte_to_pa(*pte);
            if (0 == old_pa) {
              UNLOCK_PVH(pai);  /* some other path beat us to it */
              old_pa_locked = FALSE;
            }
          }
  
  
          /*
           *      Special case if the incoming physical page is already mapped
           *      at this address.
           */
          if (old_pa == pa) {
  
              /*
               *  May be changing its wired attribute or protection
               */
  
              template = pa_to_pte(pa) | INTEL_PTE_VALID;
  
              if(VM_MEM_NOT_CACHEABLE == (flags & (VM_MEM_NOT_CACHEABLE | VM_WIMG_USE_DEFAULT))) {
                  if(!(flags & VM_MEM_GUARDED))
                          template |= INTEL_PTE_PTA;
                  template |= INTEL_PTE_NCACHE;
              }
  
              if (pmap != kernel_pmap)
                  template |= INTEL_PTE_USER;
              if (prot & VM_PROT_WRITE)
                  template |= INTEL_PTE_WRITE;
  
              if (set_NX == TRUE)
                  template |= INTEL_PTE_NX;
  
              if (wired) {
                  template |= INTEL_PTE_WIRED;
                  if (!iswired(*pte))
                      OSAddAtomic(+1,  &pmap->stats.wired_count);
              }
              else {
                  if (iswired(*pte)) {
                      assert(pmap->stats.wired_count >= 1);
                      OSAddAtomic(-1,  &pmap->stats.wired_count);
                  }
              }
  
              /* store modified PTE and preserve RC bits */ 
              pmap_update_pte(pte, *pte, template | (*pte & (INTEL_PTE_REF | INTEL_PTE_MOD)));
              if (old_pa_locked) {
                UNLOCK_PVH(pai);
                old_pa_locked = FALSE;
              }
              need_tlbflush = TRUE;
              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.
           *
           *      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 != (pmap_paddr_t) 0) {
  
              /*
               *  Don't do anything to pages outside valid memory here.
               *  Instead convince the code that enters a new mapping
               *  to overwrite the old one.
               */
  
              /* invalidate the PTE */ 
              pmap_update_pte(pte, *pte, (*pte & ~INTEL_PTE_VALID));
              /* propagate invalidate everywhere */
              PMAP_UPDATE_TLBS(pmap, vaddr, vaddr + PAGE_SIZE);
              /* remember reference and change */
              oattr = (char)(*pte & (PHYS_MODIFIED | PHYS_REFERENCED));
              /* completely invalidate the PTE */
              pmap_store_pte(pte, 0);
  
              if (managed_page(pai)) {
  #if TESTING
                  if (pmap->stats.resident_count < 1)
                      panic("pmap_enter: resident_count");
  #endif
                  assert(pmap->stats.resident_count >= 1);
                  OSAddAtomic(-1,  &pmap->stats.resident_count);
  
                  if (iswired(*pte)) {
  
  #if TESTING
                      if (pmap->stats.wired_count < 1)
                          panic("pmap_enter: wired_count");
  #endif
                      assert(pmap->stats.wired_count >= 1);
                      OSAddAtomic(-1,  &pmap->stats.wired_count);
                  }
  
                  pmap_phys_attributes[pai] |= oattr;
                  /*
                   *      Remove the mapping from the pvlist for
                   *      this physical page.
                   *      We'll end up with either a rooted pv or a
                   *      hashed pv
                   */
                  {
  
                      pv_h = pai_to_pvh(pai);
  
                      if (pv_h->pmap == PMAP_NULL) {
                          panic("pmap_enter: null pv_list!");
                      }
  
                      if (pv_h->va == vaddr && pv_h->pmap == pmap) {
                          /*
                           * Header is the pv_rooted_entry.  
                           * If there is a next one, copy it to the
                           * header and free the next one (we cannot
                           * free the header)
                           */
                        pvh_e = (pv_hashed_entry_t)queue_next(&pv_h->qlink);
                        if (pvh_e != (pv_hashed_entry_t)pv_h) {
                          pvhash_idx = pvhashidx(pvh_e->pmap, pvh_e->va);
                          LOCK_PV_HASH(pvhash_idx);
                            remque(&pvh_e->qlink);
                            pmap_pvh_unlink(pvh_e);
                            UNLOCK_PV_HASH(pvhash_idx);
                            pv_h->pmap = pvh_e->pmap;
                            pv_h->va = pvh_e->va;
                          }
                        else {
                          pv_h->pmap = PMAP_NULL;
                          pvh_e = PV_HASHED_ENTRY_NULL;
                        }
                      }
                      else {
                        pv_hashed_entry_t *pprevh;
                        ppnum_t old_ppn;
                        /* wasn't the rooted pv - hash, find it, and unlink it */
                        old_ppn = (ppnum_t)pa_index(old_pa);
                        CHK_NPVHASH();
                        pvhash_idx = pvhashidx(pmap,vaddr);
                        LOCK_PV_HASH(pvhash_idx);
                        pprevh = pvhash(pvhash_idx);
  #if PV_DEBUG
                        if (NULL==pprevh)panic("pmap enter 1");
  #endif
                        pvh_e = *pprevh;
                        pmap_pv_hashlist_walks++;
                        pv_cnt = 0;
                        while (PV_HASHED_ENTRY_NULL != pvh_e) {
                          pv_cnt++;
                          if (pvh_e->pmap == pmap && pvh_e->va == vaddr && pvh_e->ppn == old_ppn) break;
                          pprevh = &pvh_e->nexth;
                          pvh_e = pvh_e->nexth;
                        }
                        pmap_pv_hashlist_cnts += pv_cnt;
                        if (pmap_pv_hashlist_max < pv_cnt) pmap_pv_hashlist_max = pv_cnt;
                        if (PV_HASHED_ENTRY_NULL == pvh_e) panic("pmap_enter: pv not in hash list");
                        if(NULL==pprevh)panic("pmap enter 2");
                        *pprevh = pvh_e->nexth;
                        remque(&pvh_e->qlink);
                        UNLOCK_PV_HASH(pvhash_idx);
                      }
                  }
              }
              else {
                  /*
                   *      old_pa is not managed.
                   *      Do removal part of accounting.
                   */
  
                  if (iswired(*pte)) {
                      assert(pmap->stats.wired_count >= 1);
                      OSAddAtomic(-1,  &pmap->stats.wired_count);
                  }
              }
          }
  
          /*
           * if we had a previously managed paged locked, unlock it now
           */
  
          if (old_pa_locked) {
            UNLOCK_PVH(pai);
            old_pa_locked = FALSE;
          }
  
          pai = pa_index(pa);     /* now working with new incoming phys page */
          if (managed_page(pai)) {
  
              /*
               *  Step 2) Enter the mapping in the PV list for this
               *  physical page.
               */
              pv_h = pai_to_pvh(pai);
  
              LOCK_PVH(pai);
  
              if (pv_h->pmap == PMAP_NULL) {
                  /*
                   *      No mappings yet, use  rooted pv
                   */
                  pv_h->va = vaddr;
                  pv_h->pmap = pmap;
                  queue_init(&pv_h->qlink);
              }
              else {
                  /*
                   *      Add new pv_hashed_entry after header.
                   */
                  if ((PV_HASHED_ENTRY_NULL == pvh_e) && pvh_new) {
                    pvh_e = pvh_new;
                    pvh_new = PV_HASHED_ENTRY_NULL;  /* show we used it */
                  } else if (PV_HASHED_ENTRY_NULL == pvh_e) {
                    PV_HASHED_ALLOC(pvh_e);
                    if (PV_HASHED_ENTRY_NULL == pvh_e) {
                      /* the pv list is empty.
                       * if we are on the kernel pmap we'll use one of the special private
                       * kernel pv_e's, else, we need to unlock everything, zalloc a pv_e,
                       * and restart bringing in the pv_e with us.
                       */
                      if (kernel_pmap == pmap) {
                        PV_HASHED_KERN_ALLOC(pvh_e);
                      } else {
                        UNLOCK_PVH(pai);
                        PMAP_UNLOCK(pmap);
                        pvh_new = (pv_hashed_entry_t) zalloc(pv_hashed_list_zone);
                        goto Retry;
                      }
                    }
                  }
  
                  if (PV_HASHED_ENTRY_NULL == pvh_e) panic("pvh_e exhaustion");
                  pvh_e->va = vaddr;
                  pvh_e->pmap = pmap;
                  pvh_e->ppn = pn;
                  CHK_NPVHASH();
                  pvhash_idx = pvhashidx(pmap,vaddr);
                  LOCK_PV_HASH(pvhash_idx);
                  insque(&pvh_e->qlink, &pv_h->qlink);
                  hashp = pvhash(pvhash_idx);
  #if PV_DEBUG
                  if(NULL==hashp)panic("pmap_enter 4");
  #endif
                  pvh_e->nexth = *hashp;
                  *hashp = pvh_e;
                  UNLOCK_PV_HASH(pvhash_idx);
  
                  /*
                   *      Remember that we used the pvlist entry.
                   */
                  pvh_e = PV_HASHED_ENTRY_NULL;
              }
  
              /*
               * only count the mapping
               * for 'managed memory'
               */
              OSAddAtomic(+1,  &pmap->stats.resident_count);
              if (pmap->stats.resident_count > pmap->stats.resident_max) {
                      pmap->stats.resident_max = pmap->stats.resident_count;
              }
          }
  
          /*
           * Step 3) Enter the mapping.
           *
           *      Build a template to speed up entering -
           *      only the pfn changes.
           */
          template = pa_to_pte(pa) | INTEL_PTE_VALID;
  
          if (flags & VM_MEM_NOT_CACHEABLE) {
                  if(!(flags & VM_MEM_GUARDED))
                          template |= INTEL_PTE_PTA;
                  template |= INTEL_PTE_NCACHE;
          }
  
          if (pmap != kernel_pmap)
                  template |= INTEL_PTE_USER;
          if (prot & VM_PROT_WRITE)
                  template |= INTEL_PTE_WRITE;
  
          if (set_NX == TRUE)
                  template |= INTEL_PTE_NX;
  
          if (wired) {
                  template |= INTEL_PTE_WIRED;
                  OSAddAtomic(+1,  &pmap->stats.wired_count);
          }
          pmap_store_pte(pte, template);
  
          /* if this was a managed page we delayed unlocking the pv until here
           * to prevent pmap_page_protect et al from finding it until the pte
           * has been stored */
  
          if (managed_page(pai)) {
            UNLOCK_PVH(pai);
          }
  
  Done:
          if (need_tlbflush == TRUE)
                  PMAP_UPDATE_TLBS(pmap, vaddr, vaddr + PAGE_SIZE);
  
          if (pvh_e != PV_HASHED_ENTRY_NULL) {
                  PV_HASHED_FREE_LIST(pvh_e, pvh_e, 1);
          }
  
          if (pvh_new != PV_HASHED_ENTRY_NULL) {
            PV_HASHED_KERN_FREE_LIST(pvh_new, pvh_new, 1);
          }
  
          PMAP_UNLOCK(pmap);
          PMAP_TRACE(PMAP_CODE(PMAP__ENTER) | DBG_FUNC_END, 0, 0, 0, 0, 0);
  }
  
  /*
   *      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_map_offset_t vaddr,
          boolean_t       wired)
  {
          register pt_entry_t     *pte;
  
          /*
           *      We must grab the pmap system lock because we may
           *      change a pte_page queue.
           */
          PMAP_LOCK(map);
  
          if ((pte = pmap_pte(map, vaddr)) == PT_ENTRY_NULL)
                  panic("pmap_change_wiring: pte missing");
  
          if (wired && !iswired(*pte)) {
              /*
               *  wiring down mapping
               */
              OSAddAtomic(+1,  &map->stats.wired_count);
              pmap_update_pte(pte, *pte, (*pte | INTEL_PTE_WIRED));
          }
          else if (!wired && iswired(*pte)) {
              /*
               *  unwiring mapping
               */
              assert(map->stats.wired_count >= 1);
              OSAddAtomic(-1,  &map->stats.wired_count);
              pmap_update_pte(pte, *pte, (*pte & ~INTEL_PTE_WIRED));
          }
  
          PMAP_UNLOCK(map);
  }
  
  
  /*
   *      Routine:        pmap_extract
   *      Function:
   *              Extract the physical page address associated
   *              with the given map/virtual_address pair.
   *     Change to shim for backwards compatibility but will not
   *     work for 64 bit systems.  Some old drivers that we cannot
   *     change need this.
   */
  
  vm_offset_t
  pmap_extract(
          register pmap_t pmap,
          vm_map_offset_t vaddr)
  {
          ppnum_t ppn;
          vm_offset_t paddr;
  
          paddr = (vm_offset_t)0;
          ppn = pmap_find_phys(pmap, vaddr);
  
          if (ppn) {
                  paddr = ((vm_offset_t)i386_ptob(ppn)) | ((vm_offset_t)vaddr & INTEL_OFFMASK);
          }
          return (paddr);
  }
  
  void
  pmap_expand_pml4(
                   pmap_t map,
                   vm_map_offset_t vaddr)
  {
          register vm_page_t      m;
          register pmap_paddr_t   pa;
          uint64_t                i;
          spl_t                   spl;
          ppnum_t                 pn;
          pml4_entry_t            *pml4p;
  
          if (kernel_pmap == map) panic("expand kernel pml4");
  
          spl = splhigh();
          pml4p = pmap64_pml4(map, vaddr);
          splx(spl);
          if (PML4_ENTRY_NULL == pml4p) panic("pmap_expand_pml4 no pml4p");
  
          /*
           *      Allocate a VM page for the pml4 page
           */
          while ((m = vm_page_grab()) == VM_PAGE_NULL)
                  VM_PAGE_WAIT();
  
          /*
           *      put the page into the pmap's obj list so it
           *      can be found later.
           */
          pn = m->phys_page;
          pa = i386_ptob(pn);
          i = pml4idx(map, vaddr);
  
          /*
           *      Zero the page.
           */
          pmap_zero_page(pn);
  
          vm_page_lockspin_queues();
          vm_page_wire(m);
          vm_page_unlock_queues();
  
          OSAddAtomic(1,  &inuse_ptepages_count);
  
          /* Take the oject lock (mutex) before the PMAP_LOCK (spinlock) */
          vm_object_lock(map->pm_obj_pml4);
  
          PMAP_LOCK(map);
          /*
           *      See if someone else expanded us first
           */
          if (pmap64_pdpt(map, vaddr) != PDPT_ENTRY_NULL) {
                  PMAP_UNLOCK(map);
                  vm_object_unlock(map->pm_obj_pml4);
  
                  VM_PAGE_FREE(m);
  
                  OSAddAtomic(-1,  &inuse_ptepages_count);
                  return;
          }
  
  #if 0 /* DEBUG */
         if (0 != vm_page_lookup(map->pm_obj_pml4, (vm_object_offset_t)i)) {
                 panic("pmap_expand_pml4: obj not empty, pmap %p pm_obj %p vaddr 0x%llx i 0x%llx\n",
                       map, map->pm_obj_pml4, vaddr, i);
         }
  #endif
          vm_page_insert(m, map->pm_obj_pml4, (vm_object_offset_t)i);
          vm_object_unlock(map->pm_obj_pml4);
  
          /*
           *      Set the page directory entry for this page table.
           */
          pml4p = pmap64_pml4(map, vaddr); /* refetch under lock */
  
          pmap_store_pte(pml4p, pa_to_pte(pa)
                                  | INTEL_PTE_VALID
                                  | INTEL_PTE_USER
                                  | INTEL_PTE_WRITE);
  
          PMAP_UNLOCK(map);
  
          return;
  
  }
  
  void
  pmap_expand_pdpt(
                   pmap_t map,
                   vm_map_offset_t vaddr)
  {
          register vm_page_t      m;
          register pmap_paddr_t   pa;
          uint64_t                i;
          spl_t                   spl;
          ppnum_t                 pn;
          pdpt_entry_t            *pdptp;
  
          if (kernel_pmap == map) panic("expand kernel pdpt");
  
          spl = splhigh();
          while ((pdptp = pmap64_pdpt(map, vaddr)) == PDPT_ENTRY_NULL) {
                  splx(spl);
                  pmap_expand_pml4(map, vaddr); /* need room for another pdpt entry */
                  spl = splhigh();
          }
          splx(spl);
  
          /*
           *      Allocate a VM page for the pdpt page
           */
          while ((m = vm_page_grab()) == VM_PAGE_NULL)
                  VM_PAGE_WAIT();
  
          /*
           *      put the page into the pmap's obj list so it
           *      can be found later.
           */
          pn = m->phys_page;
          pa = i386_ptob(pn);
          i = pdptidx(map, vaddr);
  
          /*
           *      Zero the page.
           */
          pmap_zero_page(pn);
  
          vm_page_lockspin_queues();
          vm_page_wire(m);
          vm_page_unlock_queues();
  
          OSAddAtomic(1,  &inuse_ptepages_count);
  
          /* Take the oject lock (mutex) before the PMAP_LOCK (spinlock) */
          vm_object_lock(map->pm_obj_pdpt);
  
          PMAP_LOCK(map);
          /*
           *      See if someone else expanded us first
           */
          if (pmap64_pde(map, vaddr) != PD_ENTRY_NULL) {
                  PMAP_UNLOCK(map);
                  vm_object_unlock(map->pm_obj_pdpt);
  
                  VM_PAGE_FREE(m);
  
                  OSAddAtomic(-1,  &inuse_ptepages_count);
                  return;
          }
  
  #if 0 /* DEBUG */
         if (0 != vm_page_lookup(map->pm_obj_pdpt, (vm_object_offset_t)i)) {
                 panic("pmap_expand_pdpt: obj not empty, pmap %p pm_obj %p vaddr 0x%llx i 0x%llx\n",
                       map, map->pm_obj_pdpt, vaddr, i);
         }
  #endif
          vm_page_insert(m, map->pm_obj_pdpt, (vm_object_offset_t)i);
          vm_object_unlock(map->pm_obj_pdpt);
  
          /*
           *      Set the page directory entry for this page table.
           */
          pdptp = pmap64_pdpt(map, vaddr); /* refetch under lock */
  
          pmap_store_pte(pdptp, pa_to_pte(pa)
                                  | INTEL_PTE_VALID
                                  | INTEL_PTE_USER
                                  | INTEL_PTE_WRITE);
  
          PMAP_UNLOCK(map);
  
          return;
  
  }
  
  
  
  /*
   *      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(
          pmap_t          map,
          vm_map_offset_t vaddr)
  {
          pt_entry_t              *pdp;
          register vm_page_t      m;
          register pmap_paddr_t   pa;
          uint64_t                 i;
          spl_t                   spl;
          ppnum_t                 pn;
  
          /*
           * if not the kernel map (while we are still compat kernel mode)
           * and we are 64 bit, propagate expand upwards
           */
  
          if (cpu_64bit && (map != kernel_pmap)) {
                  spl = splhigh();
                  while ((pdp = pmap64_pde(map, vaddr)) == PD_ENTRY_NULL) {
                          splx(spl);
                          pmap_expand_pdpt(map, vaddr); /* need room for another pde entry */
                          spl = splhigh();
                  }
                  splx(spl);
          }
  
          /*
           *      Allocate a VM page for the pde entries.
           */
          while ((m = vm_page_grab()) == VM_PAGE_NULL)
                  VM_PAGE_WAIT();
  
          /*
           *      put the page into the pmap's obj list so it
           *      can be found later.
           */
          pn = m->phys_page;
          pa = i386_ptob(pn);
          i = pdeidx(map, vaddr);
  
          /*
           *      Zero the page.
           */
          pmap_zero_page(pn);
  
          vm_page_lockspin_queues();
          vm_page_wire(m);
          vm_page_unlock_queues();
  
          OSAddAtomic(1,  &inuse_ptepages_count);
  
          /* Take the oject lock (mutex) before the PMAP_LOCK (spinlock) */
          vm_object_lock(map->pm_obj);
  
          PMAP_LOCK(map);
          /*
           *      See if someone else expanded us first
           */
  
          if (pmap_pte(map, vaddr) != PT_ENTRY_NULL) {
                  PMAP_UNLOCK(map);
                  vm_object_unlock(map->pm_obj);
  
                  VM_PAGE_FREE(m);
  
                  OSAddAtomic(-1,  &inuse_ptepages_count);
                  return;
          }
  
  #if 0 /* DEBUG */
         if (0 != vm_page_lookup(map->pm_obj, (vm_object_offset_t)i)) {
                 panic("pmap_expand: obj not empty, pmap 0x%x pm_obj 0x%x vaddr 0x%llx i 0x%llx\n",
                       map, map->pm_obj, vaddr, i);
         }
  #endif
          vm_page_insert(m, map->pm_obj, (vm_object_offset_t)i);
          vm_object_unlock(map->pm_obj);
  
          /*
           * refetch while locked 
           */
  
          pdp = pmap_pde(map, vaddr);
  
          /*
           *      Set the page directory entry for this page table.
           */
          pmap_store_pte(pdp, pa_to_pte(pa)
                                  | INTEL_PTE_VALID
                                  | INTEL_PTE_USER
                                  | INTEL_PTE_WRITE);
  
          PMAP_UNLOCK(map);
  
          return;
  }
  
  
  /*
   * pmap_sync_page_data_phys(ppnum_t pa)
   * 
   * Invalidates all of the instruction cache on a physical page and
   * pushes any dirty data from the data cache for the same physical page
   * Not required in i386.
   */
  void
  pmap_sync_page_data_phys(__unused ppnum_t pa)
  {
          return;
  }
  
  /*
   * pmap_sync_page_attributes_phys(ppnum_t pa)
   * 
   * Write back and invalidate all cachelines on a physical page.
   */
  void
  pmap_sync_page_attributes_phys(ppnum_t pa)
  {
          cache_flush_page_phys(pa);
  }
  
  
  
  #ifdef CURRENTLY_UNUSED_AND_UNTESTED
  
  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;
          int                     wired;
  
          if (p == PMAP_NULL)
                  return;
  
          if (p == kernel_pmap)
                  return;
  
          /*
           *      Garbage collect map.
           */
          PMAP_LOCK(p);
  
          for (pdp = (pt_entry_t *)p->dirbase;
               pdp < (pt_entry_t *)&p->dirbase[(UMAXPTDI+1)];
               pdp++)
          {
             if (*pdp & INTEL_PTE_VALID) {
                if(*pdp & INTEL_PTE_REF) {
                  pmap_store_pte(pdp, *pdp & ~INTEL_PTE_REF);
                  collect_ref++;
                } else {
                  collect_unref++;
                  ptp = pmap_pte(p, pdetova(pdp - (pt_entry_t *)p->dirbase));
                  eptp = ptp + NPTEPG;
  
                  /*
                   * 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 - (pt_entry_t *)p->dirbase),
                                  ptp,
                                  eptp);
  
                      /*
                       * Invalidate the page directory pointer.
                       */
                      pmap_store_pte(pdp, 0x0);
                   
                      PMAP_UNLOCK(p);
  
                      /*
                       * And free the pte page itself.
                       */
                      {
                          register vm_page_t m;
  
                          vm_object_lock(p->pm_obj);
  
                          m = vm_page_lookup(p->pm_obj,(vm_object_offset_t)(pdp - (pt_entry_t *)&p->dirbase[0]));
                          if (m == VM_PAGE_NULL)
                              panic("pmap_collect: pte page not in object");
  
                          VM_PAGE_FREE(m);
  
                          OSAddAtomic(-1,  &inuse_ptepages_count);
  
                          vm_object_unlock(p->pm_obj);
                      }
  
                      PMAP_LOCK(p);
                  }
                }
             }
          }
  
          PMAP_UPDATE_TLBS(p, 0x0, 0xFFFFFFFFFFFFF000ULL);
          PMAP_UNLOCK(p);
          return;
  
  }
  #endif
  
  
  void
  pmap_copy_page(ppnum_t src, ppnum_t dst)
  {
    bcopy_phys((addr64_t)i386_ptob(src),
               (addr64_t)i386_ptob(dst),
               PAGE_SIZE);
  }
  
  
  /*
   *      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(
          __unused pmap_t         pmap,
          __unused vm_map_offset_t        start_addr,
          __unused vm_map_offset_t        end_addr,
          __unused boolean_t      pageable)
  {
  #ifdef  lint
          pmap++; start_addr++; end_addr++; pageable++;
  #endif  /* lint */
  }
  
  /*
   *      Clear specified attribute bits.
   */
  void
  phys_attribute_clear(
          ppnum_t         pn,
          int             bits)
  {
          pv_rooted_entry_t               pv_h;
          register pv_hashed_entry_t      pv_e;
          register pt_entry_t     *pte;
          int                     pai;
          register pmap_t         pmap;
  
          pmap_intr_assert();
          assert(pn != vm_page_fictitious_addr);
          if (pn == vm_page_guard_addr)
                  return;
  
          pai = ppn_to_pai(pn);
  
          if (!managed_page(pai)) {
              /*
               *  Not a managed page.
               */
              return;
          }
  
  
          PMAP_TRACE(PMAP_CODE(PMAP__ATTRIBUTE_CLEAR) | DBG_FUNC_START,
                     (int) pn, bits, 0, 0, 0);
  
          pv_h = pai_to_pvh(pai);
  
          LOCK_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.
               */
  
            pv_e = (pv_hashed_entry_t)pv_h;
  
            do {
                  pmap = pv_e->pmap;
  
                  {
                      vm_map_offset_t va;
  
                      va = pv_e->va;
  
                      /*
                       * Clear modify and/or reference bits.
                       */
  
                      pte = pmap_pte(pmap, va);
                      pmap_update_pte(pte, *pte, (*pte & ~bits));
                      /* Ensure all processors using this translation
                       * invalidate this TLB entry. The invalidation *must* follow
                       * the PTE update, to ensure that the TLB shadow of the
                       * 'D' bit (in particular) is synchronized with the
                       * updated PTE.
                       */
                      PMAP_UPDATE_TLBS(pmap, va, va + PAGE_SIZE);
                  }
  
                  pv_e = (pv_hashed_entry_t)queue_next(&pv_e->qlink);
  
            } while (pv_e != (pv_hashed_entry_t)pv_h);
          }
          pmap_phys_attributes[pai] &= ~bits;
  
          UNLOCK_PVH(pai);
  
          PMAP_TRACE(PMAP_CODE(PMAP__ATTRIBUTE_CLEAR) | DBG_FUNC_END,
                     0, 0, 0, 0, 0);
  
  }
  
  /*
   *      Check specified attribute bits.
   */
  int
  phys_attribute_test(
          ppnum_t         pn,
          int             bits)
  {
          pv_rooted_entry_t               pv_h;
          register pv_hashed_entry_t      pv_e;
          register pt_entry_t     *pte;
          int                     pai;
          register pmap_t         pmap;
          int                     attributes = 0;
  
          pmap_intr_assert();
          assert(pn != vm_page_fictitious_addr);
          if (pn == vm_page_guard_addr)
                  return 0;
  
          pai = ppn_to_pai(pn);
  
          if (!managed_page(pai)) {
              /*
               *  Not a managed page.
               */
              return (0);
          }
  
          /*
           * super fast check...  if bits already collected
           * no need to take any locks...
           * if not set, we need to recheck after taking
           * the lock in case they got pulled in while
           * we were waiting for the lock
           */
          if ( (pmap_phys_attributes[pai] & bits) == bits)
              return (bits);
  
          pv_h = pai_to_pvh(pai);
  
          LOCK_PVH(pai);
  
          attributes = pmap_phys_attributes[pai] & bits;
  
  
          /*
           * Walk down PV list, checking the mappings until we
           * reach the end or we've found the attributes we've asked for
           * 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.
               */
            pv_e = (pv_hashed_entry_t)pv_h;
            if (attributes != bits) do {
  
                  pmap = pv_e->pmap;
  
                  {
                      vm_map_offset_t va;
  
                      va = pv_e->va;
                      /*
                       * first make sure any processor actively
                       * using this pmap, flushes its TLB state
                       */
                      PMAP_UPDATE_TLBS(pmap, va, va + PAGE_SIZE);
  
                      /*
                       * pick up modify and/or reference bits from this mapping
                       */
                      pte = pmap_pte(pmap, va);
                      attributes |= (int)(*pte & bits);
  
                  }
  
                  pv_e = (pv_hashed_entry_t)queue_next(&pv_e->qlink);
  
              } while ((attributes != bits) && (pv_e != (pv_hashed_entry_t)pv_h));
          }
  
          UNLOCK_PVH(pai);
          return (attributes);
  }
  
  /*
   *      Set specified attribute bits.
   */
  void
  phys_attribute_set(
          ppnum_t         pn,
          int             bits)
  {
          int             pai;
  
          pmap_intr_assert();
          assert(pn != vm_page_fictitious_addr);
          if (pn == vm_page_guard_addr)
                  return;
  
          pai = ppn_to_pai(pn);
  
          if (!managed_page(pai)) {
              /*
               *  Not a managed page.
               */
              return;
          }
  
          LOCK_PVH(pai);
  
          pmap_phys_attributes[pai] |= bits;
  
          UNLOCK_PVH(pai);
  }
  
  /*
   *      Set the modify bit on the specified physical page.
   */
  
  void pmap_set_modify(
                       ppnum_t pn)
  {
          phys_attribute_set(pn, PHYS_MODIFIED);
  }
  
  /*
   *      Clear the modify bits on the specified physical page.
   */
  
  void
  pmap_clear_modify(
                    ppnum_t pn)
  {
          phys_attribute_clear(pn, PHYS_MODIFIED);
  }
  
  /*
   *      pmap_is_modified:
   *
   *      Return whether or not the specified physical page is modified
   *      by any physical maps.
   */
  
  boolean_t
  pmap_is_modified(
                   ppnum_t pn)
  {
          if (phys_attribute_test(pn, PHYS_MODIFIED))
                  return TRUE;
  
          return FALSE;
  }
  
  /*
   *      pmap_clear_reference:
   *
   *      Clear the reference bit on the specified physical page.
   */
  
  void
  pmap_clear_reference(
                       ppnum_t pn)
  {
          phys_attribute_clear(pn, PHYS_REFERENCED);
  }
  
  void
  pmap_set_reference(ppnum_t pn)
  {
          phys_attribute_set(pn, PHYS_REFERENCED);
  }
  
  /*
   *      pmap_is_referenced:
   *
   *      Return whether or not the specified physical page is referenced
   *      by any physical maps.
   */
  
  boolean_t
  pmap_is_referenced(
                     ppnum_t pn)
  {
          if (phys_attribute_test(pn, PHYS_REFERENCED))
                  return TRUE;
  
          return FALSE;
  }
  
  /*
   * pmap_get_refmod(phys)
   *  returns the referenced and modified bits of the specified
   *  physical page.
   */
  unsigned int
  pmap_get_refmod(ppnum_t pa)
  {
          int     refmod;
          unsigned int retval = 0;
  
          refmod = phys_attribute_test(pa, PHYS_MODIFIED | PHYS_REFERENCED);
  
          if (refmod & PHYS_MODIFIED)
                  retval |= VM_MEM_MODIFIED;
          if (refmod & PHYS_REFERENCED)
                  retval |= VM_MEM_REFERENCED;
  
          return (retval);
  }
  
  /*
   * pmap_clear_refmod(phys, mask)
   *  clears the referenced and modified bits as specified by the mask
   *  of the specified physical page.
   */
  void
  pmap_clear_refmod(ppnum_t pa, unsigned int mask)
  {
          unsigned int  x86Mask;
  
          x86Mask = (   ((mask &   VM_MEM_MODIFIED)?   PHYS_MODIFIED : 0)
                      | ((mask & VM_MEM_REFERENCED)? PHYS_REFERENCED : 0));
          phys_attribute_clear(pa, x86Mask);
  }
  
  void 
  invalidate_icache(__unused vm_offset_t  addr,
                    __unused unsigned     cnt,
                    __unused int          phys)
  {
          return;
  }
  void 
  flush_dcache(__unused vm_offset_t       addr,
               __unused unsigned          count,
               __unused int               phys)
  {
          return;
  }
  
  #if CONFIG_DTRACE
  /*
   * Constrain DTrace copyin/copyout actions
   */
  extern kern_return_t dtrace_copyio_preflight(addr64_t);
  extern kern_return_t dtrace_copyio_postflight(addr64_t);
  
  kern_return_t dtrace_copyio_preflight(__unused addr64_t va)
  {
          thread_t thread = current_thread();
  
          if (current_map() == kernel_map)
                  return KERN_FAILURE;
          else if (thread->machine.specFlags & CopyIOActive)
                  return KERN_FAILURE;
          else
                  return KERN_SUCCESS;
  }
   
  kern_return_t dtrace_copyio_postflight(__unused addr64_t va)
  {
          return KERN_SUCCESS;
  }
  #endif /* CONFIG_DTRACE */
  
  #if     MACH_KDB
  
  /* show phys page mappings and attributes */
  
  extern void     db_show_page(pmap_paddr_t pa);
  
  #if 0
  void
  db_show_page(pmap_paddr_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 %llx ", 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("%llx in pmap %p\n", pv_h->va, pv_h->pmap);
  }
  #endif
  
  #endif /* MACH_KDB */
  
  #if     MACH_KDB
  #if 0
  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%qx", kvtophys(vaddr));
  }
  
  /*
   *      Walk the pages tables.
   */
  void
  db_show_vaddrs(
          pt_entry_t      *dirbase)
  {
          pt_entry_t      *ptep, *pdep, tmp;
          unsigned 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 *) (int) ((unsigned long) dirbase & ~INTEL_OFFMASK);
  
          db_printf("dirbase: 0x%x\n", dirbase);
  
          pdecnt = ptecnt = 0;
          pdep = &dirbase[0];
          for (y = 0; y < NPDEPG; y++, pdep++) {
                  if (((tmp = *pdep) & INTEL_PTE_VALID) == 0) {
                          continue;
                  }
                  pdecnt++;
                  ptep = (pt_entry_t *) ((unsigned long)(*pdep) & ~INTEL_OFFMASK);
                  db_printf("dir[%4d]: 0x%x\n", y, *pdep);
                  for (x = 0; x < NPTEPG; 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
  #endif  /* MACH_KDB */
  
  #include <mach_vm_debug.h>
  #if     MACH_VM_DEBUG
  #include <vm/vm_debug.h>
  
  int
  pmap_list_resident_pages(
          __unused pmap_t         pmap,
          __unused vm_offset_t    *listp,
          __unused int            space)
  {
          return 0;
  }
  #endif  /* MACH_VM_DEBUG */
  
  
  
  /* temporary workaround */
  boolean_t
  coredumpok(__unused vm_map_t map, __unused vm_offset_t va)
  {
  #if 0
          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));
  #else
          return TRUE;
  #endif
  }
  
  
  boolean_t
  phys_page_exists(
                   ppnum_t pn)
  {
          assert(pn != vm_page_fictitious_addr);
  
          if (!pmap_initialized)
                  return (TRUE);
  
          if (pn == vm_page_guard_addr)
                  return FALSE;
  
          if (!managed_page(ppn_to_pai(pn)))
                  return (FALSE);
  
          return TRUE;
  }
  
  void
  mapping_free_prime(void)
  {
          int             i;
          pv_hashed_entry_t      pvh_e;
          pv_hashed_entry_t      pvh_eh;
          pv_hashed_entry_t      pvh_et;
          int             pv_cnt;
  
          pv_cnt = 0;
          pvh_eh = pvh_et = PV_HASHED_ENTRY_NULL;
          for (i = 0; i < (5 * PV_HASHED_ALLOC_CHUNK); i++) {
                  pvh_e = (pv_hashed_entry_t) zalloc(pv_hashed_list_zone);
  
                  pvh_e->qlink.next = (queue_entry_t)pvh_eh;
                  pvh_eh = pvh_e;
  
                  if (pvh_et == PV_HASHED_ENTRY_NULL)
                          pvh_et = pvh_e;
                  pv_cnt++;
          }
          PV_HASHED_FREE_LIST(pvh_eh, pvh_et, pv_cnt);
  
          pv_cnt = 0;
          pvh_eh = pvh_et = PV_HASHED_ENTRY_NULL;
          for (i = 0; i < PV_HASHED_KERN_ALLOC_CHUNK; i++) {
                  pvh_e = (pv_hashed_entry_t) zalloc(pv_hashed_list_zone);
  
                  pvh_e->qlink.next = (queue_entry_t)pvh_eh;
                  pvh_eh = pvh_e;
  
                  if (pvh_et == PV_HASHED_ENTRY_NULL)
                          pvh_et = pvh_e;
                  pv_cnt++;
          }
          PV_HASHED_KERN_FREE_LIST(pvh_eh, pvh_et, pv_cnt);
  
  }
  
  void
  mapping_adjust(void)
  {
          pv_hashed_entry_t      pvh_e;
          pv_hashed_entry_t      pvh_eh;
          pv_hashed_entry_t      pvh_et;
          int             pv_cnt;
          int             i;
  
          if (mapping_adjust_call == NULL) {
                  thread_call_setup(&mapping_adjust_call_data,
                                    (thread_call_func_t) mapping_adjust,
                                    (thread_call_param_t) NULL);
                  mapping_adjust_call = &mapping_adjust_call_data;
          }
  
          pv_cnt = 0;
          pvh_eh = pvh_et = PV_HASHED_ENTRY_NULL;
          if (pv_hashed_kern_free_count < PV_HASHED_KERN_LOW_WATER_MARK) {
                  for (i = 0; i < PV_HASHED_KERN_ALLOC_CHUNK; i++) {
                          pvh_e = (pv_hashed_entry_t) zalloc(pv_hashed_list_zone);
  
                          pvh_e->qlink.next = (queue_entry_t)pvh_eh;
                          pvh_eh = pvh_e;
  
                          if (pvh_et == PV_HASHED_ENTRY_NULL)
                                  pvh_et = pvh_e;
                          pv_cnt++;
                  }
                  PV_HASHED_KERN_FREE_LIST(pvh_eh, pvh_et, pv_cnt);
          }
  
          pv_cnt = 0;
          pvh_eh = pvh_et = PV_HASHED_ENTRY_NULL;
          if (pv_hashed_free_count < PV_HASHED_LOW_WATER_MARK) {
                  for (i = 0; i < PV_HASHED_ALLOC_CHUNK; i++) {
                          pvh_e = (pv_hashed_entry_t) zalloc(pv_hashed_list_zone);
  
                          pvh_e->qlink.next = (queue_entry_t)pvh_eh;
                          pvh_eh = pvh_e;
  
                          if (pvh_et == PV_HASHED_ENTRY_NULL)
                                  pvh_et = pvh_e;
                          pv_cnt++;
                  }
                  PV_HASHED_FREE_LIST(pvh_eh, pvh_et, pv_cnt);
          }
          mappingrecurse = 0;
  }
  
  void
  pmap_commpage32_init(vm_offset_t kernel_commpage, vm_offset_t user_commpage, int cnt)
  {
          int i;
          pt_entry_t *opte, *npte;
          pt_entry_t pte;
          spl_t s;
  
          for (i = 0; i < cnt; i++) {
                  s = splhigh();
                  opte = pmap_pte(kernel_pmap, (vm_map_offset_t)kernel_commpage);
                  if (0 == opte)
                          panic("kernel_commpage");
                  pte = *opte | INTEL_PTE_USER|INTEL_PTE_GLOBAL;
                  pte &= ~INTEL_PTE_WRITE; // ensure read only
                  npte = pmap_pte(kernel_pmap, (vm_map_offset_t)user_commpage);
                  if (0 == npte)
                          panic("user_commpage");
                  pmap_store_pte(npte, pte);
                  splx(s);
                  kernel_commpage += INTEL_PGBYTES;
                  user_commpage += INTEL_PGBYTES;
          }
  }
  
  
  #define PMAP_COMMPAGE64_CNT  (_COMM_PAGE64_AREA_USED/PAGE_SIZE)
  pt_entry_t pmap_commpage64_ptes[PMAP_COMMPAGE64_CNT];
  
  void
  pmap_commpage64_init(vm_offset_t kernel_commpage, __unused vm_map_offset_t user_commpage, int cnt)
  {
      int i;
      pt_entry_t *kptep;
  
      PMAP_LOCK(kernel_pmap);
  
      for (i = 0; i < cnt; i++) {
          kptep = pmap_pte(kernel_pmap, (uint64_t)kernel_commpage + (i*PAGE_SIZE));
          if ((0 == kptep) || (0 == (*kptep & INTEL_PTE_VALID)))
              panic("pmap_commpage64_init pte");
          pmap_commpage64_ptes[i] = ((*kptep & ~INTEL_PTE_WRITE) | INTEL_PTE_USER);
      }
      PMAP_UNLOCK(kernel_pmap);
  }
  
  
  static cpu_pmap_t               cpu_pmap_master;
  
  struct cpu_pmap *
  pmap_cpu_alloc(boolean_t is_boot_cpu)
  {
          int                     ret;
          int                     i;
          cpu_pmap_t              *cp;
          vm_offset_t             address;
          vm_map_address_t        mapaddr;
          vm_map_entry_t          entry;
          pt_entry_t              *pte;
          
          if (is_boot_cpu) {
                  cp = &cpu_pmap_master;
          } else {
                  /*
                   * The per-cpu pmap data structure itself.
                   */
                  ret = kmem_alloc(kernel_map,
                                   (vm_offset_t *) &cp, sizeof(cpu_pmap_t));
                  if (ret != KERN_SUCCESS) {
                          printf("pmap_cpu_alloc() failed ret=%d\n", ret);
                          return NULL;
                  }
                  bzero((void *)cp, sizeof(cpu_pmap_t));
  
                  /*
                   * The temporary windows used for copy/zero - see loose_ends.c
                   */
                  ret = vm_map_find_space(kernel_map,
                      &mapaddr, PMAP_NWINDOWS*PAGE_SIZE, (vm_map_offset_t)0, 0, &entry);
                  if (ret != KERN_SUCCESS) {
                          printf("pmap_cpu_alloc() "
                                  "vm_map_find_space ret=%d\n", ret);
                          pmap_cpu_free(cp);
                          return NULL;
                  }
                  address = (vm_offset_t)mapaddr;
  
                  for (i = 0; i < PMAP_NWINDOWS; i++, address += PAGE_SIZE) {
                    spl_t s;
                          s = splhigh();
                          while ((pte = pmap_pte(kernel_pmap, (vm_map_offset_t)address)) == 0)
                                  pmap_expand(kernel_pmap, (vm_map_offset_t)address);
                          * (int *) pte = 0; 
                          cp->mapwindow[i].prv_CADDR = (caddr_t) address;
                          cp->mapwindow[i].prv_CMAP = pte;
                          splx(s);
                  }
                  vm_map_unlock(kernel_map);
          }
  
          cp->pdpt_window_index = PMAP_PDPT_FIRST_WINDOW;
          cp->pde_window_index = PMAP_PDE_FIRST_WINDOW;
          cp->pte_window_index = PMAP_PTE_FIRST_WINDOW;
  
          return cp;
  }
  
  void
  pmap_cpu_free(struct cpu_pmap *cp)
  {
          if (cp != NULL && cp != &cpu_pmap_master) {
                  kfree((void *) cp, sizeof(cpu_pmap_t));
          }
  }
  
  
  mapwindow_t *
  pmap_get_mapwindow(pt_entry_t pentry)
  {
      mapwindow_t *mp;
      int i;
  
      assert(ml_get_interrupts_enabled() == 0 || get_preemption_level() != 0);
  
      /*
       * Note: 0th map reserved for pmap_pte()
       */
      for (i = PMAP_NWINDOWS_FIRSTFREE; i < PMAP_NWINDOWS; i++) {
              mp = &current_cpu_datap()->cpu_pmap->mapwindow[i];
  
              if (*mp->prv_CMAP == 0) {
                      pmap_store_pte(mp->prv_CMAP, pentry);
  
                      invlpg((uintptr_t)mp->prv_CADDR);
  
                      return (mp);
              }
      }
      panic("pmap_get_mapwindow: no windows available");
  
      return NULL;
  }
  
  
  void
  pmap_put_mapwindow(mapwindow_t *mp)
  {
      pmap_store_pte(mp->prv_CMAP, 0);
  }
  
  void
  pmap_switch(pmap_t tpmap)
  {
          spl_t   s;
  
          s = splhigh();          /* Make sure interruptions are disabled */
  
          set_dirbase(tpmap, current_thread());
  
          splx(s);
  }
  
  
  /*
   * disable no-execute capability on
   * the specified pmap
   */
  void pmap_disable_NX(pmap_t pmap) {
    
          pmap->nx_enabled = 0;
  }
  
  void
  pt_fake_zone_info(int *count, vm_size_t *cur_size, vm_size_t *max_size, vm_size_t *elem_size,
                    vm_size_t *alloc_size, int *collectable, int *exhaustable)
  {
          *count      = inuse_ptepages_count;
          *cur_size   = PAGE_SIZE * inuse_ptepages_count;
          *max_size   = PAGE_SIZE * (inuse_ptepages_count + vm_page_inactive_count + vm_page_active_count + vm_page_free_count);
          *elem_size  = PAGE_SIZE;
          *alloc_size = PAGE_SIZE;
  
          *collectable = 1;
          *exhaustable = 0;
  }
  
  vm_offset_t pmap_cpu_high_map_vaddr(int cpu, enum high_cpu_types e)
  {
    enum high_fixed_addresses a;
    a = e + HIGH_CPU_END * cpu;
    return pmap_index_to_virt(HIGH_FIXED_CPUS_BEGIN + a);
  }
  
  vm_offset_t pmap_high_map_vaddr(enum high_cpu_types e)
  {
    return pmap_cpu_high_map_vaddr(cpu_number(), e);
  }
  
  vm_offset_t pmap_high_map(pt_entry_t pte, enum high_cpu_types e)
  {
    enum high_fixed_addresses a;
    vm_offset_t vaddr;
  
    a = e + HIGH_CPU_END * cpu_number();
    vaddr = (vm_offset_t)pmap_index_to_virt(HIGH_FIXED_CPUS_BEGIN + a);
    pmap_store_pte(pte_unique_base + a, pte);
  
    /* TLB flush for this page for this  cpu */
    invlpg((uintptr_t)vaddr);
  
    return  vaddr;
  }
  
  static inline void
  pmap_cpuset_NMIPI(cpu_set cpu_mask) {
          unsigned int cpu, cpu_bit;
          uint64_t deadline;
  
          for (cpu = 0, cpu_bit = 1; cpu < real_ncpus; cpu++, cpu_bit <<= 1) {
                  if (cpu_mask & cpu_bit)
                          cpu_NMI_interrupt(cpu);
          }
          deadline = mach_absolute_time() + (LockTimeOut);
          while (mach_absolute_time() < deadline)
                  cpu_pause();
  }
  
  /*
   * Called with pmap locked, we:
   *  - scan through per-cpu data to see which other cpus need to flush
   *  - send an IPI to each non-idle cpu to be flushed
   *  - wait for all to signal back that they are inactive or we see that
   *    they are in an interrupt handler or at a safe point
   *  - flush the local tlb is active for this pmap
   *  - return ... the caller will unlock the pmap
   */
  void
  pmap_flush_tlbs(pmap_t  pmap)
  {
          unsigned int    cpu;
          unsigned int    cpu_bit;
          cpu_set         cpus_to_signal;
          unsigned int    my_cpu = cpu_number();
          pmap_paddr_t    pmap_cr3 = pmap->pm_cr3;
          boolean_t       flush_self = FALSE;
          uint64_t        deadline;
  
          assert((processor_avail_count < 2) ||
                 (ml_get_interrupts_enabled() && get_preemption_level() != 0));
  
          /*
           * Scan other cpus for matching active or task CR3.
           * For idle cpus (with no active map) we mark them invalid but
           * don't signal -- they'll check as they go busy.
           * Note: for the kernel pmap we look for 64-bit shared address maps.
           */
          cpus_to_signal = 0;
          for (cpu = 0, cpu_bit = 1; cpu < real_ncpus; cpu++, cpu_bit <<= 1) {
                  if (!cpu_datap(cpu)->cpu_running)
                          continue;
                  if ((cpu_datap(cpu)->cpu_task_cr3 == pmap_cr3) ||
                      (CPU_GET_ACTIVE_CR3(cpu)      == pmap_cr3) ||
                      (pmap->pm_shared) ||
                      ((pmap == kernel_pmap) &&
                       (!CPU_CR3_IS_ACTIVE(cpu) ||
                        cpu_datap(cpu)->cpu_task_map == TASK_MAP_64BIT_SHARED))) {
                          if (cpu == my_cpu) {
                                  flush_self = TRUE;
                                  continue;
                          }
                          cpu_datap(cpu)->cpu_tlb_invalid = TRUE;
                          __asm__ volatile("mfence");
  
                          if (CPU_CR3_IS_ACTIVE(cpu)) {
                                  cpus_to_signal |= cpu_bit;
                                  i386_signal_cpu(cpu, MP_TLB_FLUSH, ASYNC);
                          }
                  }
          }
  
          PMAP_TRACE(PMAP_CODE(PMAP__FLUSH_TLBS) | DBG_FUNC_START,
                     (int) pmap, cpus_to_signal, flush_self, 0, 0);
  
          if (cpus_to_signal) {
                  cpu_set cpus_to_respond = cpus_to_signal;
  
                  deadline = mach_absolute_time() + LockTimeOut;
                  /*
                   * Wait for those other cpus to acknowledge
                   */
                  while (cpus_to_respond != 0) {
                          if (mach_absolute_time() > deadline) {
                                  if (mp_recent_debugger_activity())
                                          continue;
                                  if (!panic_active()) {
                                          pmap_tlb_flush_timeout = TRUE;
                                          pmap_cpuset_NMIPI(cpus_to_respond);
                                  }
                                  panic("pmap_flush_tlbs() timeout: "
                                      "cpu(s) failing to respond to interrupts, pmap=%p cpus_to_respond=0x%lx",
                                      pmap, cpus_to_respond);
                          }
  
                          for (cpu = 0, cpu_bit = 1; cpu < real_ncpus; cpu++, cpu_bit <<= 1) {
                                  if ((cpus_to_respond & cpu_bit) != 0) {
                                          if (!cpu_datap(cpu)->cpu_running ||
                                              cpu_datap(cpu)->cpu_tlb_invalid == FALSE ||
                                              !CPU_CR3_IS_ACTIVE(cpu)) {
                                                  cpus_to_respond &= ~cpu_bit;
                                          }
                                          cpu_pause();
                                  }
                                  if (cpus_to_respond == 0)
                                          break;
                          }
                  }
          }
          /*
           * Flush local tlb if required.
           * We need this flush even if the pmap being changed
           * is the user map... in case we do a copyin/out
           * before returning to user mode.
           */
          if (flush_self)
                  flush_tlb();
  
          if ((pmap == kernel_pmap) && (flush_self != TRUE)) {
                  panic("pmap_flush_tlbs: pmap == kernel_pmap && flush_self != TRUE; kernel CR3: 0x%llX, CPU active CR3: 0x%llX, CPU Task Map: %d", kernel_pmap->pm_cr3, current_cpu_datap()->cpu_active_cr3, current_cpu_datap()->cpu_task_map);
          }
  
          PMAP_TRACE(PMAP_CODE(PMAP__FLUSH_TLBS) | DBG_FUNC_END,
                     (int) pmap, cpus_to_signal, flush_self, 0, 0);
  }
  
  void
  process_pmap_updates(void)
  {
          assert(ml_get_interrupts_enabled() == 0 || get_preemption_level() != 0);
  
          flush_tlb();
  
          current_cpu_datap()->cpu_tlb_invalid = FALSE;
          __asm__ volatile("mfence");
  }
  
  void
  pmap_update_interrupt(void)
  {
          PMAP_TRACE(PMAP_CODE(PMAP__UPDATE_INTERRUPT) | DBG_FUNC_START,
                     0, 0, 0, 0, 0);
  
          process_pmap_updates();
  
          PMAP_TRACE(PMAP_CODE(PMAP__UPDATE_INTERRUPT) | DBG_FUNC_END,
                     0, 0, 0, 0, 0);
  }
  
  
  unsigned int pmap_cache_attributes(ppnum_t pn) {
  
          if (!managed_page(ppn_to_pai(pn)))
                  return (VM_WIMG_IO);
  
          return (VM_WIMG_COPYBACK);
  }
  
  #ifdef PMAP_DEBUG
  void
  pmap_dump(pmap_t p)
  {
    int i;
  
    kprintf("pmap 0x%x\n",p);
  
    kprintf("  pm_cr3 0x%llx\n",p->pm_cr3);
    kprintf("  pm_pml4 0x%x\n",p->pm_pml4);
    kprintf("  pm_pdpt 0x%x\n",p->pm_pdpt);
  
    kprintf("    pml4[0] 0x%llx\n",*p->pm_pml4);
    for (i=0;i<8;i++)
      kprintf("    pdpt[%d] 0x%llx\n",i, p->pm_pdpt[i]);
  }
  
  void pmap_dump_wrap(void)
  {
    pmap_dump(current_cpu_datap()->cpu_active_thread->task->map->pmap);
  }
  
  void
  dump_4GB_pdpt(pmap_t p)
  {
          int             spl;
          pdpt_entry_t    *user_pdptp;
          pdpt_entry_t    *kern_pdptp;
          pdpt_entry_t    *pml4p;
  
          spl = splhigh();
          while ((user_pdptp = pmap64_pdpt(p, 0x0)) == PDPT_ENTRY_NULL) {
                  splx(spl);
                  pmap_expand_pml4(p, 0x0);
                  spl = splhigh();
          }
          kern_pdptp = kernel_pmap->pm_pdpt;
          if (kern_pdptp == NULL)
                  panic("kern_pdptp == NULL");
          kprintf("dump_4GB_pdpt(%p)\n"
                  "kern_pdptp=%p (phys=0x%016llx)\n"
                  "\t 0x%08x: 0x%016llx\n"
                  "\t 0x%08x: 0x%016llx\n"
                  "\t 0x%08x: 0x%016llx\n"
                  "\t 0x%08x: 0x%016llx\n"
                  "\t 0x%08x: 0x%016llx\n"
                  "user_pdptp=%p (phys=0x%016llx)\n"
                  "\t 0x%08x: 0x%016llx\n"
                  "\t 0x%08x: 0x%016llx\n"
                  "\t 0x%08x: 0x%016llx\n"
                  "\t 0x%08x: 0x%016llx\n"
                  "\t 0x%08x: 0x%016llx\n",
                  p, kern_pdptp, kvtophys(kern_pdptp),
                  kern_pdptp+0, *(kern_pdptp+0),
                  kern_pdptp+1, *(kern_pdptp+1),
                  kern_pdptp+2, *(kern_pdptp+2),
                  kern_pdptp+3, *(kern_pdptp+3),
                  kern_pdptp+4, *(kern_pdptp+4),
                  user_pdptp, kvtophys(user_pdptp),
                  user_pdptp+0, *(user_pdptp+0),
                  user_pdptp+1, *(user_pdptp+1),
                  user_pdptp+2, *(user_pdptp+2),
                  user_pdptp+3, *(user_pdptp+3),
                  user_pdptp+4, *(user_pdptp+4));
          kprintf("user pm_cr3=0x%016llx pm_hold=0x%08x pm_pml4=0x%08x\n",
                  p->pm_cr3, p->pm_hold, p->pm_pml4);
          pml4p = (pdpt_entry_t *)p->pm_hold;
          if (pml4p == NULL)
                  panic("user pml4p == NULL");
          kprintf("\t 0x%08x: 0x%016llx\n"
                  "\t 0x%08x: 0x%016llx\n",
                  pml4p+0, *(pml4p),
                  pml4p+KERNEL_UBER_PML4_INDEX, *(pml4p+KERNEL_UBER_PML4_INDEX));
          kprintf("kern pm_cr3=0x%016llx pm_hold=0x%08x pm_pml4=0x%08x\n",
                  kernel_pmap->pm_cr3, kernel_pmap->pm_hold, kernel_pmap->pm_pml4);
          pml4p = (pdpt_entry_t *)kernel_pmap->pm_hold;
          if (pml4p == NULL)
                  panic("kern pml4p == NULL");
          kprintf("\t 0x%08x: 0x%016llx\n"
                  "\t 0x%08x: 0x%016llx\n",
                  pml4p+0, *(pml4p),
                  pml4p+511, *(pml4p+511));
          splx(spl);
  }
  
  void dump_4GB_pdpt_thread(thread_t tp)
  {
          dump_4GB_pdpt(tp->map->pmap);
  }
  
  
  #endif