FreeBSD/Linux Kernel Cross Reference
sys/arm/arm/pmap-v6.c

     /* From: $NetBSD: pmap.c,v 1.148 2004/04/03 04:35:48 bsh Exp $ */
     /*-
      * Copyright 2011 Semihalf
      * Copyright 2004 Olivier Houchard.
      * Copyright 2003 Wasabi Systems, Inc.
      * All rights reserved.
      *
      * Written by Steve C. Woodford for Wasabi Systems, Inc.
      *
     * Redistribution and use in source and binary forms, with or without
     * modification, are permitted provided that the following conditions
     * are met:
     * 1. Redistributions of source code must retain the above copyright
     *    notice, this list of conditions and the following disclaimer.
     * 2. Redistributions in binary form must reproduce the above copyright
     *    notice, this list of conditions and the following disclaimer in the
     *    documentation and/or other materials provided with the distribution.
     * 3. All advertising materials mentioning features or use of this software
     *    must display the following acknowledgement:
     *      This product includes software developed for the NetBSD Project by
     *      Wasabi Systems, Inc.
     * 4. The name of Wasabi Systems, Inc. may not be used to endorse
     *    or promote products derived from this software without specific prior
     *    written permission.
     *
     * THIS SOFTWARE IS PROVIDED BY WASABI SYSTEMS, INC. ``AS IS'' AND
     * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
     * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
     * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL WASABI SYSTEMS, INC
     * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
     * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
     * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
     * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
     * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
     * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
     * POSSIBILITY OF SUCH DAMAGE.
     *
     * From: FreeBSD: src/sys/arm/arm/pmap.c,v 1.113 2009/07/24 13:50:29
     */
    
    /*-
     * Copyright (c) 2002-2003 Wasabi Systems, Inc.
     * Copyright (c) 2001 Richard Earnshaw
     * Copyright (c) 2001-2002 Christopher Gilbert
     * All rights reserved.
     *
     * 1. Redistributions of source code must retain the above copyright
     *    notice, this list of conditions and the following disclaimer.
     * 2. Redistributions in binary form must reproduce the above copyright
     *    notice, this list of conditions and the following disclaimer in the
     *    documentation and/or other materials provided with the distribution.
     * 3. The name of the company nor the name of the author may be used to
     *    endorse or promote products derived from this software without specific
     *    prior written permission.
     *
     * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
     * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
     * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
     * IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
     * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
     * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
     * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     * SUCH DAMAGE.
     */
    /*-
     * Copyright (c) 1999 The NetBSD Foundation, Inc.
     * All rights reserved.
     *
     * This code is derived from software contributed to The NetBSD Foundation
     * by Charles M. Hannum.
     *
     * Redistribution and use in source and binary forms, with or without
     * modification, are permitted provided that the following conditions
     * are met:
     * 1. Redistributions of source code must retain the above copyright
     *    notice, this list of conditions and the following disclaimer.
     * 2. Redistributions in binary form must reproduce the above copyright
     *    notice, this list of conditions and the following disclaimer in the
     *    documentation and/or other materials provided with the distribution.
     *
     * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
     * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
     * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
     * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
     * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
     * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
     * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
     * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
     * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
     * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
     * POSSIBILITY OF SUCH DAMAGE.
     */
    
    /*-
     * Copyright (c) 1994-1998 Mark Brinicombe.
     * Copyright (c) 1994 Brini.
    * All rights reserved.
    *
    * This code is derived from software written for Brini by Mark Brinicombe
    *
    * Redistribution and use in source and binary forms, with or without
    * modification, are permitted provided that the following conditions
    * are met:
    * 1. Redistributions of source code must retain the above copyright
    *    notice, this list of conditions and the following disclaimer.
    * 2. Redistributions in binary form must reproduce the above copyright
    *    notice, this list of conditions and the following disclaimer in the
    *    documentation and/or other materials provided with the distribution.
    * 3. All advertising materials mentioning features or use of this software
    *    must display the following acknowledgement:
    *      This product includes software developed by Mark Brinicombe.
    * 4. The name of the author may not be used to endorse or promote products
    *    derived from this software without specific prior written permission.
    *
    * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
    * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
    * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
    * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
    * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
    * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
    * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
    * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
    * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
    *
    * RiscBSD kernel project
    *
    * pmap.c
    *
    * Machine dependant vm stuff
    *
    * Created      : 20/09/94
    */
   
   /*
    * Special compilation symbols
    * PMAP_DEBUG           - Build in pmap_debug_level code
    */
   /* Include header files */
   
   #include "opt_vm.h"
   #include "opt_pmap.h"
   
   #include <sys/cdefs.h>
   __FBSDID("$FreeBSD: releng/10.0/sys/arm/arm/pmap-v6.c 255724 2013-09-20 04:30:18Z alc $");
   #include <sys/param.h>
   #include <sys/systm.h>
   #include <sys/kernel.h>
   #include <sys/ktr.h>
   #include <sys/lock.h>
   #include <sys/proc.h>
   #include <sys/malloc.h>
   #include <sys/msgbuf.h>
   #include <sys/mutex.h>
   #include <sys/vmmeter.h>
   #include <sys/mman.h>
   #include <sys/rwlock.h>
   #include <sys/smp.h>
   #include <sys/sched.h>
   #include <sys/sysctl.h>
   
   #include <vm/vm.h>
   #include <vm/vm_param.h>
   #include <vm/uma.h>
   #include <vm/pmap.h>
   #include <vm/vm_kern.h>
   #include <vm/vm_object.h>
   #include <vm/vm_map.h>
   #include <vm/vm_page.h>
   #include <vm/vm_pageout.h>
   #include <vm/vm_extern.h>
   #include <vm/vm_reserv.h>
   
   #include <machine/md_var.h>
   #include <machine/cpu.h>
   #include <machine/cpufunc.h>
   #include <machine/pcb.h>
   
   #ifdef DEBUG
   extern int last_fault_code;
   #endif
   
   #ifdef PMAP_DEBUG
   #define PDEBUG(_lev_,_stat_) \
           if (pmap_debug_level >= (_lev_)) \
                   ((_stat_))
   #define dprintf printf
   
   int pmap_debug_level = 0;
   #define PMAP_INLINE
   #else   /* PMAP_DEBUG */
   #define PDEBUG(_lev_,_stat_) /* Nothing */
   #define dprintf(x, arg...)
   #define PMAP_INLINE __inline
   #endif  /* PMAP_DEBUG */
   
   #ifdef PV_STATS
   #define PV_STAT(x)      do { x ; } while (0)
   #else
   #define PV_STAT(x)      do { } while (0)
   #endif
   
   #define pa_to_pvh(pa)   (&pv_table[pa_index(pa)])
   
   #ifdef ARM_L2_PIPT
   #define pmap_l2cache_wbinv_range(va, pa, size) cpu_l2cache_wbinv_range((pa), (size))
   #define pmap_l2cache_inv_range(va, pa, size) cpu_l2cache_inv_range((pa), (size))
   #else
   #define pmap_l2cache_wbinv_range(va, pa, size) cpu_l2cache_wbinv_range((va), (size))
   #define pmap_l2cache_inv_range(va, pa, size) cpu_l2cache_inv_range((va), (size))
   #endif
   
   extern struct pv_addr systempage;
   
   /*
    * Internal function prototypes
    */
   
   static PMAP_INLINE
   struct pv_entry         *pmap_find_pv(struct md_page *, pmap_t, vm_offset_t);
   static void             pmap_free_pv_chunk(struct pv_chunk *pc);
   static void             pmap_free_pv_entry(pmap_t pmap, pv_entry_t pv);
   static pv_entry_t       pmap_get_pv_entry(pmap_t pmap, boolean_t try);
   static vm_page_t        pmap_pv_reclaim(pmap_t locked_pmap);
   static boolean_t        pmap_pv_insert_section(pmap_t, vm_offset_t,
       vm_paddr_t);
   static struct pv_entry  *pmap_remove_pv(struct vm_page *, pmap_t, vm_offset_t);
   static int              pmap_pvh_wired_mappings(struct md_page *, int);
   
   static void             pmap_enter_locked(pmap_t, vm_offset_t, vm_prot_t,
       vm_page_t, vm_prot_t, boolean_t, int);
   static vm_paddr_t       pmap_extract_locked(pmap_t pmap, vm_offset_t va);
   static void             pmap_alloc_l1(pmap_t);
   static void             pmap_free_l1(pmap_t);
   
   static void             pmap_map_section(pmap_t, vm_offset_t, vm_offset_t,
       vm_prot_t, boolean_t);
   static void             pmap_promote_section(pmap_t, vm_offset_t);
   static boolean_t        pmap_demote_section(pmap_t, vm_offset_t);
   static boolean_t        pmap_enter_section(pmap_t, vm_offset_t, vm_page_t,
       vm_prot_t);
   static void             pmap_remove_section(pmap_t, vm_offset_t);
   
   static int              pmap_clearbit(struct vm_page *, u_int);
   
   static struct l2_bucket *pmap_get_l2_bucket(pmap_t, vm_offset_t);
   static struct l2_bucket *pmap_alloc_l2_bucket(pmap_t, vm_offset_t);
   static void             pmap_free_l2_bucket(pmap_t, struct l2_bucket *, u_int);
   static vm_offset_t      kernel_pt_lookup(vm_paddr_t);
   
   static MALLOC_DEFINE(M_VMPMAP, "pmap", "PMAP L1");
   
   vm_offset_t virtual_avail;      /* VA of first avail page (after kernel bss) */
   vm_offset_t virtual_end;        /* VA of last avail page (end of kernel AS) */
   vm_offset_t pmap_curmaxkvaddr;
   vm_paddr_t kernel_l1pa;
   
   vm_offset_t kernel_vm_end = 0;
   
   vm_offset_t vm_max_kernel_address;
   
   struct pmap kernel_pmap_store;
   
   static pt_entry_t *csrc_pte, *cdst_pte;
   static vm_offset_t csrcp, cdstp;
   static struct mtx cmtx;
   
   static void             pmap_init_l1(struct l1_ttable *, pd_entry_t *);
   /*
    * These routines are called when the CPU type is identified to set up
    * the PTE prototypes, cache modes, etc.
    *
    * The variables are always here, just in case LKMs need to reference
    * them (though, they shouldn't).
    */
   static void pmap_set_prot(pt_entry_t *pte, vm_prot_t prot, uint8_t user);
   pt_entry_t      pte_l1_s_cache_mode;
   pt_entry_t      pte_l1_s_cache_mode_pt;
   
   pt_entry_t      pte_l2_l_cache_mode;
   pt_entry_t      pte_l2_l_cache_mode_pt;
   
   pt_entry_t      pte_l2_s_cache_mode;
   pt_entry_t      pte_l2_s_cache_mode_pt;
   
   struct msgbuf *msgbufp = 0;
   
   /*
    * Crashdump maps.
    */
   static caddr_t crashdumpmap;
   
   extern void bcopy_page(vm_offset_t, vm_offset_t);
   extern void bzero_page(vm_offset_t);
   
   char *_tmppt;
   
   /*
    * Metadata for L1 translation tables.
    */
   struct l1_ttable {
           /* Entry on the L1 Table list */
           SLIST_ENTRY(l1_ttable) l1_link;
   
           /* Entry on the L1 Least Recently Used list */
           TAILQ_ENTRY(l1_ttable) l1_lru;
   
           /* Track how many domains are allocated from this L1 */
           volatile u_int l1_domain_use_count;
   
           /*
            * A free-list of domain numbers for this L1.
            * We avoid using ffs() and a bitmap to track domains since ffs()
            * is slow on ARM.
            */
           u_int8_t l1_domain_first;
           u_int8_t l1_domain_free[PMAP_DOMAINS];
   
           /* Physical address of this L1 page table */
           vm_paddr_t l1_physaddr;
   
           /* KVA of this L1 page table */
           pd_entry_t *l1_kva;
   };
   
   /*
    * Convert a virtual address into its L1 table index. That is, the
    * index used to locate the L2 descriptor table pointer in an L1 table.
    * This is basically used to index l1->l1_kva[].
    *
    * Each L2 descriptor table represents 1MB of VA space.
    */
   #define L1_IDX(va)              (((vm_offset_t)(va)) >> L1_S_SHIFT)
   
   /*
    * L1 Page Tables are tracked using a Least Recently Used list.
    *  - New L1s are allocated from the HEAD.
    *  - Freed L1s are added to the TAIl.
    *  - Recently accessed L1s (where an 'access' is some change to one of
    *    the userland pmaps which owns this L1) are moved to the TAIL.
    */
   static TAILQ_HEAD(, l1_ttable) l1_lru_list;
   /*
    * A list of all L1 tables
    */
   static SLIST_HEAD(, l1_ttable) l1_list;
   static struct mtx l1_lru_lock;
   
   /*
    * The l2_dtable tracks L2_BUCKET_SIZE worth of L1 slots.
    *
    * This is normally 16MB worth L2 page descriptors for any given pmap.
    * Reference counts are maintained for L2 descriptors so they can be
    * freed when empty.
    */
   struct l2_dtable {
           /* The number of L2 page descriptors allocated to this l2_dtable */
           u_int l2_occupancy;
   
           /* List of L2 page descriptors */
           struct l2_bucket {
                   pt_entry_t *l2b_kva;    /* KVA of L2 Descriptor Table */
                   vm_paddr_t l2b_phys;    /* Physical address of same */
                   u_short l2b_l1idx;      /* This L2 table's L1 index */
                   u_short l2b_occupancy;  /* How many active descriptors */
           } l2_bucket[L2_BUCKET_SIZE];
   };
   
   /* pmap_kenter_internal flags */
   #define KENTER_CACHE    0x1
   #define KENTER_USER     0x2
   
   /*
    * Given an L1 table index, calculate the corresponding l2_dtable index
    * and bucket index within the l2_dtable.
    */
   #define L2_IDX(l1idx)           (((l1idx) >> L2_BUCKET_LOG2) & \
                                    (L2_SIZE - 1))
   #define L2_BUCKET(l1idx)        ((l1idx) & (L2_BUCKET_SIZE - 1))
   
   /*
    * Given a virtual address, this macro returns the
    * virtual address required to drop into the next L2 bucket.
    */
   #define L2_NEXT_BUCKET(va)      (((va) & L1_S_FRAME) + L1_S_SIZE)
   
   /*
    * We try to map the page tables write-through, if possible.  However, not
    * all CPUs have a write-through cache mode, so on those we have to sync
    * the cache when we frob page tables.
    *
    * We try to evaluate this at compile time, if possible.  However, it's
    * not always possible to do that, hence this run-time var.
    */
   int     pmap_needs_pte_sync;
   
   /*
    * Macro to determine if a mapping might be resident in the
    * instruction cache and/or TLB
    */
   #define PTE_BEEN_EXECD(pte)  (L2_S_EXECUTABLE(pte) && L2_S_REFERENCED(pte))
   
   /*
    * Macro to determine if a mapping might be resident in the
    * data cache and/or TLB
    */
   #define PTE_BEEN_REFD(pte)   (L2_S_REFERENCED(pte))
   
   #ifndef PMAP_SHPGPERPROC
   #define PMAP_SHPGPERPROC 200
   #endif
   
   #define pmap_is_current(pm)     ((pm) == pmap_kernel() || \
               curproc->p_vmspace->vm_map.pmap == (pm))
   
   /*
    * Data for the pv entry allocation mechanism
    */
   static TAILQ_HEAD(pch, pv_chunk) pv_chunks = TAILQ_HEAD_INITIALIZER(pv_chunks);
   static int pv_entry_count, pv_entry_max, pv_entry_high_water;
   static struct md_page *pv_table;
   static int shpgperproc = PMAP_SHPGPERPROC;
   
   struct pv_chunk *pv_chunkbase;          /* KVA block for pv_chunks */
   int pv_maxchunks;                       /* How many chunks we have KVA for */
   vm_offset_t pv_vafree;                  /* Freelist stored in the PTE */
   
   static __inline struct pv_chunk *
   pv_to_chunk(pv_entry_t pv)
   {
   
           return ((struct pv_chunk *)((uintptr_t)pv & ~(uintptr_t)PAGE_MASK));
   }
   
   #define PV_PMAP(pv) (pv_to_chunk(pv)->pc_pmap)
   
   CTASSERT(sizeof(struct pv_chunk) == PAGE_SIZE);
   CTASSERT(_NPCM == 8);
   CTASSERT(_NPCPV == 252);
   
   #define PC_FREE0_6      0xfffffffful    /* Free values for index 0 through 6 */
   #define PC_FREE7        0x0ffffffful    /* Free values for index 7 */
   
   static const uint32_t pc_freemask[_NPCM] = {
           PC_FREE0_6, PC_FREE0_6, PC_FREE0_6,
           PC_FREE0_6, PC_FREE0_6, PC_FREE0_6,
           PC_FREE0_6, PC_FREE7
   };
   
   static SYSCTL_NODE(_vm, OID_AUTO, pmap, CTLFLAG_RD, 0, "VM/pmap parameters");
   
   /* Superpages utilization enabled = 1 / disabled = 0 */
   static int sp_enabled = 0;
   SYSCTL_INT(_vm_pmap, OID_AUTO, sp_enabled, CTLFLAG_RDTUN, &sp_enabled, 0,
       "Are large page mappings enabled?");
   
   SYSCTL_INT(_vm_pmap, OID_AUTO, pv_entry_count, CTLFLAG_RD, &pv_entry_count, 0,
       "Current number of pv entries");
   
   #ifdef PV_STATS
   static int pc_chunk_count, pc_chunk_allocs, pc_chunk_frees, pc_chunk_tryfail;
   
   SYSCTL_INT(_vm_pmap, OID_AUTO, pc_chunk_count, CTLFLAG_RD, &pc_chunk_count, 0,
       "Current number of pv entry chunks");
   SYSCTL_INT(_vm_pmap, OID_AUTO, pc_chunk_allocs, CTLFLAG_RD, &pc_chunk_allocs, 0,
       "Current number of pv entry chunks allocated");
   SYSCTL_INT(_vm_pmap, OID_AUTO, pc_chunk_frees, CTLFLAG_RD, &pc_chunk_frees, 0,
       "Current number of pv entry chunks frees");
   SYSCTL_INT(_vm_pmap, OID_AUTO, pc_chunk_tryfail, CTLFLAG_RD, &pc_chunk_tryfail, 0,
       "Number of times tried to get a chunk page but failed.");
   
   static long pv_entry_frees, pv_entry_allocs;
   static int pv_entry_spare;
   
   SYSCTL_LONG(_vm_pmap, OID_AUTO, pv_entry_frees, CTLFLAG_RD, &pv_entry_frees, 0,
       "Current number of pv entry frees");
   SYSCTL_LONG(_vm_pmap, OID_AUTO, pv_entry_allocs, CTLFLAG_RD, &pv_entry_allocs, 0,
       "Current number of pv entry allocs");
   SYSCTL_INT(_vm_pmap, OID_AUTO, pv_entry_spare, CTLFLAG_RD, &pv_entry_spare, 0,
       "Current number of spare pv entries");
   #endif
   
   uma_zone_t l2zone;
   static uma_zone_t l2table_zone;
   static vm_offset_t pmap_kernel_l2dtable_kva;
   static vm_offset_t pmap_kernel_l2ptp_kva;
   static vm_paddr_t pmap_kernel_l2ptp_phys;
   static struct rwlock pvh_global_lock;
   
   int l1_mem_types[] = {
           ARM_L1S_STRONG_ORD,
           ARM_L1S_DEVICE_NOSHARE,
           ARM_L1S_DEVICE_SHARE,
           ARM_L1S_NRML_NOCACHE,
           ARM_L1S_NRML_IWT_OWT,
           ARM_L1S_NRML_IWB_OWB,
           ARM_L1S_NRML_IWBA_OWBA
   };
   
   int l2l_mem_types[] = {
           ARM_L2L_STRONG_ORD,
           ARM_L2L_DEVICE_NOSHARE,
           ARM_L2L_DEVICE_SHARE,
           ARM_L2L_NRML_NOCACHE,
           ARM_L2L_NRML_IWT_OWT,
           ARM_L2L_NRML_IWB_OWB,
           ARM_L2L_NRML_IWBA_OWBA
   };
   
   int l2s_mem_types[] = {
           ARM_L2S_STRONG_ORD,
           ARM_L2S_DEVICE_NOSHARE,
           ARM_L2S_DEVICE_SHARE,
           ARM_L2S_NRML_NOCACHE,
           ARM_L2S_NRML_IWT_OWT,
           ARM_L2S_NRML_IWB_OWB,
           ARM_L2S_NRML_IWBA_OWBA
   };
   
   /*
    * This list exists for the benefit of pmap_map_chunk().  It keeps track
    * of the kernel L2 tables during bootstrap, so that pmap_map_chunk() can
    * find them as necessary.
    *
    * Note that the data on this list MUST remain valid after initarm() returns,
    * as pmap_bootstrap() uses it to contruct L2 table metadata.
    */
   SLIST_HEAD(, pv_addr) kernel_pt_list = SLIST_HEAD_INITIALIZER(kernel_pt_list);
   
   static void
   pmap_init_l1(struct l1_ttable *l1, pd_entry_t *l1pt)
   {
           int i;
   
           l1->l1_kva = l1pt;
           l1->l1_domain_use_count = 0;
           l1->l1_domain_first = 0;
   
           for (i = 0; i < PMAP_DOMAINS; i++)
                   l1->l1_domain_free[i] = i + 1;
   
           /*
            * Copy the kernel's L1 entries to each new L1.
            */
           if (l1pt != pmap_kernel()->pm_l1->l1_kva)
                   memcpy(l1pt, pmap_kernel()->pm_l1->l1_kva, L1_TABLE_SIZE);
   
           if ((l1->l1_physaddr = pmap_extract(pmap_kernel(), (vm_offset_t)l1pt)) == 0)
                   panic("pmap_init_l1: can't get PA of L1 at %p", l1pt);
           SLIST_INSERT_HEAD(&l1_list, l1, l1_link);
           TAILQ_INSERT_TAIL(&l1_lru_list, l1, l1_lru);
   }
   
   static vm_offset_t
   kernel_pt_lookup(vm_paddr_t pa)
   {
           struct pv_addr *pv;
   
           SLIST_FOREACH(pv, &kernel_pt_list, pv_list) {
                   if (pv->pv_pa == pa)
                           return (pv->pv_va);
           }
           return (0);
   }
   
   void
   pmap_pte_init_mmu_v6(void)
   {
   
           if (PTE_PAGETABLE >= 3)
                   pmap_needs_pte_sync = 1;
           pte_l1_s_cache_mode = l1_mem_types[PTE_CACHE];
           pte_l2_l_cache_mode = l2l_mem_types[PTE_CACHE];
           pte_l2_s_cache_mode = l2s_mem_types[PTE_CACHE];
   
           pte_l1_s_cache_mode_pt = l1_mem_types[PTE_PAGETABLE];
           pte_l2_l_cache_mode_pt = l2l_mem_types[PTE_PAGETABLE];
           pte_l2_s_cache_mode_pt = l2s_mem_types[PTE_PAGETABLE];
   
   }
   
   /*
    * Allocate an L1 translation table for the specified pmap.
    * This is called at pmap creation time.
    */
   static void
   pmap_alloc_l1(pmap_t pmap)
   {
           struct l1_ttable *l1;
           u_int8_t domain;
   
           /*
            * Remove the L1 at the head of the LRU list
            */
           mtx_lock(&l1_lru_lock);
           l1 = TAILQ_FIRST(&l1_lru_list);
           TAILQ_REMOVE(&l1_lru_list, l1, l1_lru);
   
           /*
            * Pick the first available domain number, and update
            * the link to the next number.
            */
           domain = l1->l1_domain_first;
           l1->l1_domain_first = l1->l1_domain_free[domain];
   
           /*
            * If there are still free domain numbers in this L1,
            * put it back on the TAIL of the LRU list.
            */
           if (++l1->l1_domain_use_count < PMAP_DOMAINS)
                   TAILQ_INSERT_TAIL(&l1_lru_list, l1, l1_lru);
   
           mtx_unlock(&l1_lru_lock);
   
           /*
            * Fix up the relevant bits in the pmap structure
            */
           pmap->pm_l1 = l1;
           pmap->pm_domain = domain + 1;
   }
   
   /*
    * Free an L1 translation table.
    * This is called at pmap destruction time.
    */
   static void
   pmap_free_l1(pmap_t pmap)
   {
           struct l1_ttable *l1 = pmap->pm_l1;
   
           mtx_lock(&l1_lru_lock);
   
           /*
            * If this L1 is currently on the LRU list, remove it.
            */
           if (l1->l1_domain_use_count < PMAP_DOMAINS)
                   TAILQ_REMOVE(&l1_lru_list, l1, l1_lru);
   
           /*
            * Free up the domain number which was allocated to the pmap
            */
           l1->l1_domain_free[pmap->pm_domain - 1] = l1->l1_domain_first;
           l1->l1_domain_first = pmap->pm_domain - 1;
           l1->l1_domain_use_count--;
   
           /*
            * The L1 now must have at least 1 free domain, so add
            * it back to the LRU list. If the use count is zero,
            * put it at the head of the list, otherwise it goes
            * to the tail.
            */
           if (l1->l1_domain_use_count == 0) {
                   TAILQ_INSERT_HEAD(&l1_lru_list, l1, l1_lru);
           }       else
                   TAILQ_INSERT_TAIL(&l1_lru_list, l1, l1_lru);
   
           mtx_unlock(&l1_lru_lock);
   }
   
   /*
    * Returns a pointer to the L2 bucket associated with the specified pmap
    * and VA, or NULL if no L2 bucket exists for the address.
    */
   static PMAP_INLINE struct l2_bucket *
   pmap_get_l2_bucket(pmap_t pmap, vm_offset_t va)
   {
           struct l2_dtable *l2;
           struct l2_bucket *l2b;
           u_short l1idx;
   
           l1idx = L1_IDX(va);
   
           if ((l2 = pmap->pm_l2[L2_IDX(l1idx)]) == NULL ||
               (l2b = &l2->l2_bucket[L2_BUCKET(l1idx)])->l2b_kva == NULL)
                   return (NULL);
   
           return (l2b);
   }
   
   /*
    * Returns a pointer to the L2 bucket associated with the specified pmap
    * and VA.
    *
    * If no L2 bucket exists, perform the necessary allocations to put an L2
    * bucket/page table in place.
    *
    * Note that if a new L2 bucket/page was allocated, the caller *must*
    * increment the bucket occupancy counter appropriately *before*
    * releasing the pmap's lock to ensure no other thread or cpu deallocates
    * the bucket/page in the meantime.
    */
   static struct l2_bucket *
   pmap_alloc_l2_bucket(pmap_t pmap, vm_offset_t va)
   {
           struct l2_dtable *l2;
           struct l2_bucket *l2b;
           u_short l1idx;
   
           l1idx = L1_IDX(va);
   
           PMAP_ASSERT_LOCKED(pmap);
           rw_assert(&pvh_global_lock, RA_WLOCKED);
           if ((l2 = pmap->pm_l2[L2_IDX(l1idx)]) == NULL) {
                   /*
                    * No mapping at this address, as there is
                    * no entry in the L1 table.
                    * Need to allocate a new l2_dtable.
                    */
                   PMAP_UNLOCK(pmap);
                   rw_wunlock(&pvh_global_lock);
                   if ((l2 = uma_zalloc(l2table_zone, M_NOWAIT)) == NULL) {
                           rw_wlock(&pvh_global_lock);
                           PMAP_LOCK(pmap);
                           return (NULL);
                   }
                   rw_wlock(&pvh_global_lock);
                   PMAP_LOCK(pmap);
                   if (pmap->pm_l2[L2_IDX(l1idx)] != NULL) {
                           /*
                            * Someone already allocated the l2_dtable while
                            * we were doing the same.
                            */
                           uma_zfree(l2table_zone, l2);
                           l2 = pmap->pm_l2[L2_IDX(l1idx)];
                   } else {
                           bzero(l2, sizeof(*l2));
                           /*
                            * Link it into the parent pmap
                            */
                           pmap->pm_l2[L2_IDX(l1idx)] = l2;
                   }
           }
   
           l2b = &l2->l2_bucket[L2_BUCKET(l1idx)];
   
           /*
            * Fetch pointer to the L2 page table associated with the address.
            */
           if (l2b->l2b_kva == NULL) {
                   pt_entry_t *ptep;
   
                   /*
                    * No L2 page table has been allocated. Chances are, this
                    * is because we just allocated the l2_dtable, above.
                    */
                   PMAP_UNLOCK(pmap);
                   rw_wunlock(&pvh_global_lock);
                   ptep = uma_zalloc(l2zone, M_NOWAIT);
                   rw_wlock(&pvh_global_lock);
                   PMAP_LOCK(pmap);
                   if (l2b->l2b_kva != 0) {
                           /* We lost the race. */
                           uma_zfree(l2zone, ptep);
                           return (l2b);
                   }
                   l2b->l2b_phys = vtophys(ptep);
                   if (ptep == NULL) {
                           /*
                            * Oops, no more L2 page tables available at this
                            * time. We may need to deallocate the l2_dtable
                            * if we allocated a new one above.
                            */
                           if (l2->l2_occupancy == 0) {
                                   pmap->pm_l2[L2_IDX(l1idx)] = NULL;
                                   uma_zfree(l2table_zone, l2);
                           }
                           return (NULL);
                   }
   
                   l2->l2_occupancy++;
                   l2b->l2b_kva = ptep;
                   l2b->l2b_l1idx = l1idx;
           }
   
           return (l2b);
   }
   
   static PMAP_INLINE void
   pmap_free_l2_ptp(pt_entry_t *l2)
   {
           uma_zfree(l2zone, l2);
   }
   /*
    * One or more mappings in the specified L2 descriptor table have just been
    * invalidated.
    *
    * Garbage collect the metadata and descriptor table itself if necessary.
    *
    * The pmap lock must be acquired when this is called (not necessary
    * for the kernel pmap).
    */
   static void
   pmap_free_l2_bucket(pmap_t pmap, struct l2_bucket *l2b, u_int count)
   {
           struct l2_dtable *l2;
           pd_entry_t *pl1pd, l1pd;
           pt_entry_t *ptep;
           u_short l1idx;
   
   
           /*
            * Update the bucket's reference count according to how many
            * PTEs the caller has just invalidated.
            */
           l2b->l2b_occupancy -= count;
   
           /*
            * Note:
            *
            * Level 2 page tables allocated to the kernel pmap are never freed
            * as that would require checking all Level 1 page tables and
            * removing any references to the Level 2 page table. See also the
            * comment elsewhere about never freeing bootstrap L2 descriptors.
            *
            * We make do with just invalidating the mapping in the L2 table.
            *
            * This isn't really a big deal in practice and, in fact, leads
            * to a performance win over time as we don't need to continually
            * alloc/free.
            */
           if (l2b->l2b_occupancy > 0 || pmap == pmap_kernel())
                   return;
   
           /*
            * There are no more valid mappings in this level 2 page table.
            * Go ahead and NULL-out the pointer in the bucket, then
            * free the page table.
            */
           l1idx = l2b->l2b_l1idx;
           ptep = l2b->l2b_kva;
           l2b->l2b_kva = NULL;
   
           pl1pd = &pmap->pm_l1->l1_kva[l1idx];
   
           /*
            * If the L1 slot matches the pmap's domain
            * number, then invalidate it.
            */
           l1pd = *pl1pd & (L1_TYPE_MASK | L1_C_DOM_MASK);
           if (l1pd == (L1_C_DOM(pmap->pm_domain) | L1_TYPE_C)) {
                   *pl1pd = 0;
                   PTE_SYNC(pl1pd);
           }
   
           /*
            * Release the L2 descriptor table back to the pool cache.
            */
           pmap_free_l2_ptp(ptep);
   
           /*
            * Update the reference count in the associated l2_dtable
            */
           l2 = pmap->pm_l2[L2_IDX(l1idx)];
           if (--l2->l2_occupancy > 0)
                   return;
   
           /*
            * There are no more valid mappings in any of the Level 1
            * slots managed by this l2_dtable. Go ahead and NULL-out
            * the pointer in the parent pmap and free the l2_dtable.
            */
           pmap->pm_l2[L2_IDX(l1idx)] = NULL;
           uma_zfree(l2table_zone, l2);
   }
   
   /*
    * Pool cache constructors for L2 descriptor tables, metadata and pmap
    * structures.
    */
   static int
   pmap_l2ptp_ctor(void *mem, int size, void *arg, int flags)
   {
           struct l2_bucket *l2b;
           pt_entry_t *ptep, pte;
           vm_offset_t va = (vm_offset_t)mem & ~PAGE_MASK;
   
           /*
            * The mappings for these page tables were initially made using
            * pmap_kenter() by the pool subsystem. Therefore, the cache-
            * mode will not be right for page table mappings. To avoid
            * polluting the pmap_kenter() code with a special case for
            * page tables, we simply fix up the cache-mode here if it's not
            * correct.
            */
           l2b = pmap_get_l2_bucket(pmap_kernel(), va);
           ptep = &l2b->l2b_kva[l2pte_index(va)];
           pte = *ptep;
   
           cpu_idcache_wbinv_range(va, PAGE_SIZE);
           pmap_l2cache_wbinv_range(va, pte & L2_S_FRAME, PAGE_SIZE);
           if ((pte & L2_S_CACHE_MASK) != pte_l2_s_cache_mode_pt) {
                   /*
                    * Page tables must have the cache-mode set to
                    * Write-Thru.
                    */
                   *ptep = (pte & ~L2_S_CACHE_MASK) | pte_l2_s_cache_mode_pt;
                   PTE_SYNC(ptep);
                   cpu_tlb_flushD_SE(va);
                   cpu_cpwait();
           }
   
           memset(mem, 0, L2_TABLE_SIZE_REAL);
           return (0);
   }
   
   /*
    * Modify pte bits for all ptes corresponding to the given physical address.
    * We use `maskbits' rather than `clearbits' because we're always passing
    * constants and the latter would require an extra inversion at run-time.
    */
   static int
   pmap_clearbit(struct vm_page *m, u_int maskbits)
   {
           struct l2_bucket *l2b;
           struct pv_entry *pv, *pve, *next_pv;
           struct md_page *pvh;
           pd_entry_t *pl1pd;
           pt_entry_t *ptep, npte, opte;
           pmap_t pmap;
           vm_offset_t va;
           u_int oflags;
           int count = 0;
   
           rw_wlock(&pvh_global_lock);
           if ((m->flags & PG_FICTITIOUS) != 0)
                   goto small_mappings;
   
           pvh = pa_to_pvh(VM_PAGE_TO_PHYS(m));
           TAILQ_FOREACH_SAFE(pv, &pvh->pv_list, pv_list, next_pv) {
                   va = pv->pv_va;
                   pmap = PV_PMAP(pv);
                   PMAP_LOCK(pmap);
                   pl1pd = &pmap->pm_l1->l1_kva[L1_IDX(va)];
                   KASSERT((*pl1pd & L1_TYPE_MASK) == L1_S_PROTO,
                       ("pmap_clearbit: valid section mapping expected"));
                   if ((maskbits & PVF_WRITE) && (pv->pv_flags & PVF_WRITE))
                           (void)pmap_demote_section(pmap, va);
                   else if ((maskbits & PVF_REF) && L1_S_REFERENCED(*pl1pd)) {
                           if (pmap_demote_section(pmap, va)) {
                                   if ((pv->pv_flags & PVF_WIRED) == 0) {
                                           /*
                                            * Remove the mapping to a single page
                                            * so that a subsequent access may
                                            * repromote. Since the underlying
                                            * l2_bucket is fully populated, this
                                            * removal never frees an entire
                                            * l2_bucket.
                                            */
                                           va += (VM_PAGE_TO_PHYS(m) &
                                               L1_S_OFFSET);
                                           l2b = pmap_get_l2_bucket(pmap, va);
                                           KASSERT(l2b != NULL,
                                               ("pmap_clearbit: no l2 bucket for "
                                                "va 0x%#x, pmap 0x%p", va, pmap));
                                           ptep = &l2b->l2b_kva[l2pte_index(va)];
                                           *ptep = 0;
                                           PTE_SYNC(ptep);
                                           pmap_free_l2_bucket(pmap, l2b, 1);
                                           pve = pmap_remove_pv(m, pmap, va);
                                           KASSERT(pve != NULL, ("pmap_clearbit: "
                                               "no PV entry for managed mapping"));
                                           pmap_free_pv_entry(pmap, pve);
   
                                   }
                           }
                   } else if ((maskbits & PVF_MOD) && L1_S_WRITABLE(*pl1pd)) {
                           if (pmap_demote_section(pmap, va)) {
                                   if ((pv->pv_flags & PVF_WIRED) == 0) {
                                           /*
                                            * Write protect the mapping to a
                                            * single page so that a subsequent
                                            * write access may repromote.
                                            */
                                           va += (VM_PAGE_TO_PHYS(m) &
                                               L1_S_OFFSET);
                                           l2b = pmap_get_l2_bucket(pmap, va);
                                           KASSERT(l2b != NULL,
                                               ("pmap_clearbit: no l2 bucket for "
                                                "va 0x%#x, pmap 0x%p", va, pmap));
                                           ptep = &l2b->l2b_kva[l2pte_index(va)];
                                           if ((*ptep & L2_S_PROTO) != 0) {
                                                   pve = pmap_find_pv(&m->md,
                                                       pmap, va);
                                                   KASSERT(pve != NULL,
                                                       ("pmap_clearbit: no PV "
                                                       "entry for managed mapping"));
                                                   pve->pv_flags &= ~PVF_WRITE;
                                                   *ptep |= L2_APX;
                                                   PTE_SYNC(ptep);
                                           }
                                   }
                           }
                   }
                   PMAP_UNLOCK(pmap);
           }
   
   small_mappings:
          if (TAILQ_EMPTY(&m->md.pv_list)) {
                  rw_wunlock(&pvh_global_lock);
                  return (0);
          }
  
          /*
           * Loop over all current mappings setting/clearing as appropos
           */
          TAILQ_FOREACH(pv, &m->md.pv_list, pv_list) {
                  va = pv->pv_va;
                  pmap = PV_PMAP(pv);
                  oflags = pv->pv_flags;
                  pv->pv_flags &= ~maskbits;
  
                  PMAP_LOCK(pmap);
  
                  l2b = pmap_get_l2_bucket(pmap, va);
                  KASSERT(l2b != NULL, ("pmap_clearbit: no l2 bucket for "
                      "va 0x%#x, pmap 0x%p", va, pmap));
  
                  ptep = &l2b->l2b_kva[l2pte_index(va)];
                  npte = opte = *ptep;
  
                  if (maskbits & (PVF_WRITE | PVF_MOD)) {
                          /* make the pte read only */
                          npte |= L2_APX;
                  }
  
                  if (maskbits & PVF_REF) {
                          /*
                           * Clear referenced flag in PTE so that we
                           * will take a flag fault the next time the mapping
                           * is referenced.
                           */
                          npte &= ~L2_S_REF;
                  }
  
                  CTR4(KTR_PMAP,"clearbit: pmap:%p bits:%x pte:%x->%x",
                      pmap, maskbits, opte, npte);
                  if (npte != opte) {
                          count++;
                          *ptep = npte;
                          PTE_SYNC(ptep);
                          /* Flush the TLB entry if a current pmap. */
                          if (PTE_BEEN_EXECD(opte))
                                  cpu_tlb_flushID_SE(pv->pv_va);
                          else if (PTE_BEEN_REFD(opte))
                                  cpu_tlb_flushD_SE(pv->pv_va);
                  }
  
                  PMAP_UNLOCK(pmap);
  
          }
  
          if (maskbits & PVF_WRITE)
                  vm_page_aflag_clear(m, PGA_WRITEABLE);
          rw_wunlock(&pvh_global_lock);
          return (count);
  }
  
  /*
   * main pv_entry manipulation functions:
   *   pmap_enter_pv: enter a mapping onto a vm_page list
   *   pmap_remove_pv: remove a mappiing from a vm_page list
   *
   * NOTE: pmap_enter_pv expects to lock the pvh itself
   *       pmap_remove_pv expects the caller to lock the pvh before calling
   */
  
  /*
   * pmap_enter_pv: enter a mapping onto a vm_page's PV list
   *
   * => caller should hold the proper lock on pvh_global_lock
   * => caller should have pmap locked
   * => we will (someday) gain the lock on the vm_page's PV list
   * => caller should adjust ptp's wire_count before calling
   * => caller should not adjust pmap's wire_count
   */
  static void
  pmap_enter_pv(struct vm_page *m, struct pv_entry *pve, pmap_t pmap,
      vm_offset_t va, u_int flags)
  {
  
          rw_assert(&pvh_global_lock, RA_WLOCKED);
  
          PMAP_ASSERT_LOCKED(pmap);
          pve->pv_va = va;
          pve->pv_flags = flags;
  
          TAILQ_INSERT_HEAD(&m->md.pv_list, pve, pv_list);
          if (pve->pv_flags & PVF_WIRED)
                  ++pmap->pm_stats.wired_count;
  }
  
  /*
   *
   * pmap_find_pv: Find a pv entry
   *
   * => caller should hold lock on vm_page
   */
  static PMAP_INLINE struct pv_entry *
  pmap_find_pv(struct md_page *md, pmap_t pmap, vm_offset_t va)
  {
          struct pv_entry *pv;
  
          rw_assert(&pvh_global_lock, RA_WLOCKED);
          TAILQ_FOREACH(pv, &md->pv_list, pv_list)
                  if (pmap == PV_PMAP(pv) && va == pv->pv_va)
                          break;
  
          return (pv);
  }
  
  /*
   * vector_page_setprot:
   *
   *      Manipulate the protection of the vector page.
   */
  void
  vector_page_setprot(int prot)
  {
          struct l2_bucket *l2b;
          pt_entry_t *ptep;
  
          l2b = pmap_get_l2_bucket(pmap_kernel(), vector_page);
  
          ptep = &l2b->l2b_kva[l2pte_index(vector_page)];
          /*
           * Set referenced flag.
           * Vectors' page is always desired
           * to be allowed to reside in TLB. 
           */
          *ptep |= L2_S_REF;
  
          pmap_set_prot(ptep, prot|VM_PROT_EXECUTE, 0);
  
          cpu_tlb_flushD_SE(vector_page);
          cpu_cpwait();
  }
  
  static void
  pmap_set_prot(pt_entry_t *ptep, vm_prot_t prot, uint8_t user)
  {
  
          *ptep &= ~(L2_S_PROT_MASK | L2_XN);
  
          if (!(prot & VM_PROT_EXECUTE))
                  *ptep |= L2_XN;
  
          /* Set defaults first - kernel read access */
          *ptep |= L2_APX;
          *ptep |= L2_S_PROT_R;
          /* Now tune APs as desired */
          if (user)
                  *ptep |= L2_S_PROT_U;
  
          if (prot & VM_PROT_WRITE)
                  *ptep &= ~(L2_APX);
  }
  
  /*
   * pmap_remove_pv: try to remove a mapping from a pv_list
   *
   * => caller should hold proper lock on pmap_main_lock
   * => pmap should be locked
   * => caller should hold lock on vm_page [so that attrs can be adjusted]
   * => caller should adjust ptp's wire_count and free PTP if needed
   * => caller should NOT adjust pmap's wire_count
   * => we return the removed pve
   */
  static struct pv_entry *
  pmap_remove_pv(struct vm_page *m, pmap_t pmap, vm_offset_t va)
  {
          struct pv_entry *pve;
  
          rw_assert(&pvh_global_lock, RA_WLOCKED);
          PMAP_ASSERT_LOCKED(pmap);
  
          pve = pmap_find_pv(&m->md, pmap, va);   /* find corresponding pve */
          if (pve != NULL) {
                  TAILQ_REMOVE(&m->md.pv_list, pve, pv_list);
                  if (pve->pv_flags & PVF_WIRED)
                          --pmap->pm_stats.wired_count;
          }
          if (TAILQ_EMPTY(&m->md.pv_list))
                  vm_page_aflag_clear(m, PGA_WRITEABLE);
  
          return(pve);                            /* return removed pve */
  }
  
  /*
   *
   * pmap_modify_pv: Update pv flags
   *
   * => caller should hold lock on vm_page [so that attrs can be adjusted]
   * => caller should NOT adjust pmap's wire_count
   * => we return the old flags
   *
   * Modify a physical-virtual mapping in the pv table
   */
  static u_int
  pmap_modify_pv(struct vm_page *m, pmap_t pmap, vm_offset_t va,
      u_int clr_mask, u_int set_mask)
  {
          struct pv_entry *npv;
          u_int flags, oflags;
  
          PMAP_ASSERT_LOCKED(pmap);
          rw_assert(&pvh_global_lock, RA_WLOCKED);
          if ((npv = pmap_find_pv(&m->md, pmap, va)) == NULL)
                  return (0);
  
          /*
           * There is at least one VA mapping this page.
           */
          oflags = npv->pv_flags;
          npv->pv_flags = flags = (oflags & ~clr_mask) | set_mask;
  
          if ((flags ^ oflags) & PVF_WIRED) {
                  if (flags & PVF_WIRED)
                          ++pmap->pm_stats.wired_count;
                  else
                          --pmap->pm_stats.wired_count;
          }
  
          return (oflags);
  }
  
  /* Function to set the debug level of the pmap code */
  #ifdef PMAP_DEBUG
  void
  pmap_debug(int level)
  {
          pmap_debug_level = level;
          dprintf("pmap_debug: level=%d\n", pmap_debug_level);
  }
  #endif  /* PMAP_DEBUG */
  
  void
  pmap_pinit0(struct pmap *pmap)
  {
          PDEBUG(1, printf("pmap_pinit0: pmap = %08x\n", (u_int32_t) pmap));
  
          bcopy(kernel_pmap, pmap, sizeof(*pmap));
          bzero(&pmap->pm_mtx, sizeof(pmap->pm_mtx));
          PMAP_LOCK_INIT(pmap);
          TAILQ_INIT(&pmap->pm_pvchunk);
  }
  
  /*
   *      Initialize a vm_page's machine-dependent fields.
   */
  void
  pmap_page_init(vm_page_t m)
  {
  
          TAILQ_INIT(&m->md.pv_list);
          m->md.pv_memattr = VM_MEMATTR_DEFAULT;
  }
  
  static vm_offset_t
  pmap_ptelist_alloc(vm_offset_t *head)
  {
          pt_entry_t *pte;
          vm_offset_t va;
  
          va = *head;
          if (va == 0)
                  return (va);    /* Out of memory */
          pte = vtopte(va);
          *head = *pte;
          if ((*head & L2_TYPE_MASK) != L2_TYPE_INV)
                  panic("%s: va is not L2_TYPE_INV!", __func__);
          *pte = 0;
          return (va);
  }
  
  static void
  pmap_ptelist_free(vm_offset_t *head, vm_offset_t va)
  {
          pt_entry_t *pte;
  
          if ((va & L2_TYPE_MASK) != L2_TYPE_INV)
                  panic("%s: freeing va that is not L2_TYPE INV!", __func__);
          pte = vtopte(va);
          *pte = *head;           /* virtual! L2_TYPE is L2_TYPE_INV though */
          *head = va;
  }
  
  static void
  pmap_ptelist_init(vm_offset_t *head, void *base, int npages)
  {
          int i;
          vm_offset_t va;
  
          *head = 0;
          for (i = npages - 1; i >= 0; i--) {
                  va = (vm_offset_t)base + i * PAGE_SIZE;
                  pmap_ptelist_free(head, va);
          }
  }
  
  /*
   *      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)
  {
          vm_size_t s;
          int i, pv_npg;
  
          PDEBUG(1, printf("pmap_init: phys_start = %08x\n", PHYSADDR));
  
          l2zone = uma_zcreate("L2 Table", L2_TABLE_SIZE_REAL, pmap_l2ptp_ctor,
              NULL, NULL, NULL, UMA_ALIGN_PTR, UMA_ZONE_VM | UMA_ZONE_NOFREE);
          l2table_zone = uma_zcreate("L2 Table", sizeof(struct l2_dtable), NULL,
              NULL, NULL, NULL, UMA_ALIGN_PTR, UMA_ZONE_VM | UMA_ZONE_NOFREE);
  
          /*
           * Are large page mappings supported and enabled?
           */
          TUNABLE_INT_FETCH("vm.pmap.sp_enabled", &sp_enabled);
          if (sp_enabled) {
                  KASSERT(MAXPAGESIZES > 1 && pagesizes[1] == 0,
                      ("pmap_init: can't assign to pagesizes[1]"));
                  pagesizes[1] = NBPDR;
          }
  
          /*
           * Calculate the size of the pv head table for superpages.
           */
          for (i = 0; phys_avail[i + 1]; i += 2);
          pv_npg = round_1mpage(phys_avail[(i - 2) + 1]) / NBPDR;
  
          /*
           * Allocate memory for the pv head table for superpages.
           */
          s = (vm_size_t)(pv_npg * sizeof(struct md_page));
          s = round_page(s);
          pv_table = (struct md_page *)kmem_malloc(kernel_arena, s,
              M_WAITOK | M_ZERO);
          for (i = 0; i < pv_npg; i++)
                  TAILQ_INIT(&pv_table[i].pv_list);
  
          /*
           * Initialize the address space for the pv chunks.
           */
  
          TUNABLE_INT_FETCH("vm.pmap.shpgperproc", &shpgperproc);
          pv_entry_max = shpgperproc * maxproc + cnt.v_page_count;
          TUNABLE_INT_FETCH("vm.pmap.pv_entries", &pv_entry_max);
          pv_entry_max = roundup(pv_entry_max, _NPCPV);
          pv_entry_high_water = 9 * (pv_entry_max / 10);
  
          pv_maxchunks = MAX(pv_entry_max / _NPCPV, maxproc);
          pv_chunkbase = (struct pv_chunk *)kva_alloc(PAGE_SIZE * pv_maxchunks);
  
          if (pv_chunkbase == NULL)
                  panic("pmap_init: not enough kvm for pv chunks");
  
          pmap_ptelist_init(&pv_vafree, pv_chunkbase, pv_maxchunks);
  
          /*
           * Now it is safe to enable pv_table recording.
           */
          PDEBUG(1, printf("pmap_init: done!\n"));
  }
  
  SYSCTL_INT(_vm_pmap, OID_AUTO, pv_entry_max, CTLFLAG_RD, &pv_entry_max, 0,
          "Max number of PV entries");
  SYSCTL_INT(_vm_pmap, OID_AUTO, shpgperproc, CTLFLAG_RD, &shpgperproc, 0,
          "Page share factor per proc");
  
  static SYSCTL_NODE(_vm_pmap, OID_AUTO, section, CTLFLAG_RD, 0,
      "1MB page mapping counters");
  
  static u_long pmap_section_demotions;
  SYSCTL_ULONG(_vm_pmap_section, OID_AUTO, demotions, CTLFLAG_RD,
      &pmap_section_demotions, 0, "1MB page demotions");
  
  static u_long pmap_section_mappings;
  SYSCTL_ULONG(_vm_pmap_section, OID_AUTO, mappings, CTLFLAG_RD,
      &pmap_section_mappings, 0, "1MB page mappings");
  
  static u_long pmap_section_p_failures;
  SYSCTL_ULONG(_vm_pmap_section, OID_AUTO, p_failures, CTLFLAG_RD,
      &pmap_section_p_failures, 0, "1MB page promotion failures");
  
  static u_long pmap_section_promotions;
  SYSCTL_ULONG(_vm_pmap_section, OID_AUTO, promotions, CTLFLAG_RD,
      &pmap_section_promotions, 0, "1MB page promotions");
  
  int
  pmap_fault_fixup(pmap_t pmap, vm_offset_t va, vm_prot_t ftype, int user)
  {
          struct l2_dtable *l2;
          struct l2_bucket *l2b;
          pd_entry_t *pl1pd, l1pd;
          pt_entry_t *ptep, pte;
          vm_paddr_t pa;
          u_int l1idx;
          int rv = 0;
  
          l1idx = L1_IDX(va);
          rw_wlock(&pvh_global_lock);
          PMAP_LOCK(pmap);
          /*
           * Check and possibly fix-up L1 section mapping
           * only when superpage mappings are enabled to speed up.
           */
          if (sp_enabled) {
                  pl1pd = &pmap->pm_l1->l1_kva[l1idx];
                  l1pd = *pl1pd;
                  if ((l1pd & L1_TYPE_MASK) == L1_S_PROTO) {
                          /* Catch an access to the vectors section */
                          if (l1idx == L1_IDX(vector_page))
                                  goto out;
                          /*
                           * Stay away from the kernel mappings.
                           * None of them should fault from L1 entry.
                           */
                          if (pmap == pmap_kernel())
                                  goto out;
                          /*
                           * Catch a forbidden userland access
                           */
                          if (user && !(l1pd & L1_S_PROT_U))
                                  goto out;
                          /*
                           * Superpage is always either mapped read only
                           * or it is modified and permitted to be written
                           * by default. Therefore, process only reference
                           * flag fault and demote page in case of write fault.
                           */
                          if ((ftype & VM_PROT_WRITE) && !L1_S_WRITABLE(l1pd) &&
                              L1_S_REFERENCED(l1pd)) {
                                  (void)pmap_demote_section(pmap, va);
                                  goto out;
                          } else if (!L1_S_REFERENCED(l1pd)) {
                                  /* Mark the page "referenced" */
                                  *pl1pd = l1pd | L1_S_REF;
                                  PTE_SYNC(pl1pd);
                                  goto l1_section_out;
                          } else
                                  goto out;
                  }
          }
          /*
           * If there is no l2_dtable for this address, then the process
           * has no business accessing it.
           *
           * Note: This will catch userland processes trying to access
           * kernel addresses.
           */
          l2 = pmap->pm_l2[L2_IDX(l1idx)];
          if (l2 == NULL)
                  goto out;
  
          /*
           * Likewise if there is no L2 descriptor table
           */
          l2b = &l2->l2_bucket[L2_BUCKET(l1idx)];
          if (l2b->l2b_kva == NULL)
                  goto out;
  
          /*
           * Check the PTE itself.
           */
          ptep = &l2b->l2b_kva[l2pte_index(va)];
          pte = *ptep;
          if (pte == 0)
                  goto out;
  
          /*
           * Catch a userland access to the vector page mapped at 0x0
           */
          if (user && !(pte & L2_S_PROT_U))
                  goto out;
          if (va == vector_page)
                  goto out;
  
          pa = l2pte_pa(pte);
          CTR5(KTR_PMAP, "pmap_fault_fix: pmap:%p va:%x pte:0x%x ftype:%x user:%x",
              pmap, va, pte, ftype, user);
          if ((ftype & VM_PROT_WRITE) && !(L2_S_WRITABLE(pte)) &&
              L2_S_REFERENCED(pte)) {
                  /*
                   * This looks like a good candidate for "page modified"
                   * emulation...
                   */
                  struct pv_entry *pv;
                  struct vm_page *m;
  
                  /* Extract the physical address of the page */
                  if ((m = PHYS_TO_VM_PAGE(pa)) == NULL) {
                          goto out;
                  }
                  /* Get the current flags for this page. */
  
                  pv = pmap_find_pv(&m->md, pmap, va);
                  if (pv == NULL) {
                          goto out;
                  }
  
                  /*
                   * Do the flags say this page is writable? If not then it
                   * is a genuine write fault. If yes then the write fault is
                   * our fault as we did not reflect the write access in the
                   * PTE. Now we know a write has occurred we can correct this
                   * and also set the modified bit
                   */
                  if ((pv->pv_flags & PVF_WRITE) == 0) {
                          goto out;
                  }
  
                  vm_page_dirty(m);
  
                  /* Re-enable write permissions for the page */
                  pmap_set_prot(ptep, VM_PROT_WRITE, *ptep & L2_S_PROT_U);
                  CTR1(KTR_PMAP, "pmap_fault_fix: new pte:0x%x", pte);
                  PTE_SYNC(ptep);
                  rv = 1;
          } else if (!L2_S_REFERENCED(pte)) {
                  /*
                   * This looks like a good candidate for "page referenced"
                   * emulation.
                   */
                  struct pv_entry *pv;
                  struct vm_page *m;
  
                  /* Extract the physical address of the page */
                  if ((m = PHYS_TO_VM_PAGE(pa)) == NULL)
                          goto out;
                  /* Get the current flags for this page. */
                  pv = pmap_find_pv(&m->md, pmap, va);
                  if (pv == NULL)
                          goto out;
  
                  vm_page_aflag_set(m, PGA_REFERENCED);
  
                  /* Mark the page "referenced" */
                  *ptep = pte | L2_S_REF;
                  PTE_SYNC(ptep);
                  rv = 1;
          }
  
          /*
           * We know there is a valid mapping here, so simply
           * fix up the L1 if necessary.
           */
          pl1pd = &pmap->pm_l1->l1_kva[l1idx];
          l1pd = l2b->l2b_phys | L1_C_DOM(pmap->pm_domain) | L1_C_PROTO;
          if (*pl1pd != l1pd) {
                  *pl1pd = l1pd;
                  PTE_SYNC(pl1pd);
                  rv = 1;
          }
  
  #ifdef DEBUG
          /*
           * If 'rv == 0' at this point, it generally indicates that there is a
           * stale TLB entry for the faulting address. This happens when two or
           * more processes are sharing an L1. Since we don't flush the TLB on
           * a context switch between such processes, we can take domain faults
           * for mappings which exist at the same VA in both processes. EVEN IF
           * WE'VE RECENTLY FIXED UP THE CORRESPONDING L1 in pmap_enter(), for
           * example.
           *
           * This is extremely likely to happen if pmap_enter() updated the L1
           * entry for a recently entered mapping. In this case, the TLB is
           * flushed for the new mapping, but there may still be TLB entries for
           * other mappings belonging to other processes in the 1MB range
           * covered by the L1 entry.
           *
           * Since 'rv == 0', we know that the L1 already contains the correct
           * value, so the fault must be due to a stale TLB entry.
           *
           * Since we always need to flush the TLB anyway in the case where we
           * fixed up the L1, or frobbed the L2 PTE, we effectively deal with
           * stale TLB entries dynamically.
           *
           * However, the above condition can ONLY happen if the current L1 is
           * being shared. If it happens when the L1 is unshared, it indicates
           * that other parts of the pmap are not doing their job WRT managing
           * the TLB.
           */
          if (rv == 0 && pmap->pm_l1->l1_domain_use_count == 1) {
                  printf("fixup: pmap %p, va 0x%08x, ftype %d - nothing to do!\n",
                      pmap, va, ftype);
                  printf("fixup: l2 %p, l2b %p, ptep %p, pl1pd %p\n",
                      l2, l2b, ptep, pl1pd);
                  printf("fixup: pte 0x%x, l1pd 0x%x, last code 0x%x\n",
                      pte, l1pd, last_fault_code);
  #ifdef DDB
                  Debugger();
  #endif
          }
  #endif
  
  l1_section_out:
          cpu_tlb_flushID_SE(va);
          cpu_cpwait();
  
          rv = 1;
  
  out:
          rw_wunlock(&pvh_global_lock);
          PMAP_UNLOCK(pmap);
          return (rv);
  }
  
  void
  pmap_postinit(void)
  {
          struct l2_bucket *l2b;
          struct l1_ttable *l1;
          pd_entry_t *pl1pt;
          pt_entry_t *ptep, pte;
          vm_offset_t va, eva;
          u_int loop, needed;
  
          needed = (maxproc / PMAP_DOMAINS) + ((maxproc % PMAP_DOMAINS) ? 1 : 0);
          needed -= 1;
          l1 = malloc(sizeof(*l1) * needed, M_VMPMAP, M_WAITOK);
  
          for (loop = 0; loop < needed; loop++, l1++) {
                  /* Allocate a L1 page table */
                  va = (vm_offset_t)contigmalloc(L1_TABLE_SIZE, M_VMPMAP, 0, 0x0,
                      0xffffffff, L1_TABLE_SIZE, 0);
  
                  if (va == 0)
                          panic("Cannot allocate L1 KVM");
  
                  eva = va + L1_TABLE_SIZE;
                  pl1pt = (pd_entry_t *)va;
  
                  while (va < eva) {
                                  l2b = pmap_get_l2_bucket(pmap_kernel(), va);
                                  ptep = &l2b->l2b_kva[l2pte_index(va)];
                                  pte = *ptep;
                                  pte = (pte & ~L2_S_CACHE_MASK) | pte_l2_s_cache_mode_pt;
                                  *ptep = pte;
                                  PTE_SYNC(ptep);
                                  cpu_tlb_flushD_SE(va);
  
                                  va += PAGE_SIZE;
                  }
                  pmap_init_l1(l1, pl1pt);
          }
  #ifdef DEBUG
          printf("pmap_postinit: Allocated %d static L1 descriptor tables\n",
              needed);
  #endif
  }
  
  /*
   * This is used to stuff certain critical values into the PCB where they
   * can be accessed quickly from cpu_switch() et al.
   */
  void
  pmap_set_pcb_pagedir(pmap_t pmap, struct pcb *pcb)
  {
          struct l2_bucket *l2b;
  
          pcb->pcb_pagedir = pmap->pm_l1->l1_physaddr;
          pcb->pcb_dacr = (DOMAIN_CLIENT << (PMAP_DOMAIN_KERNEL * 2)) |
              (DOMAIN_CLIENT << (pmap->pm_domain * 2));
  
          if (vector_page < KERNBASE) {
                  pcb->pcb_pl1vec = &pmap->pm_l1->l1_kva[L1_IDX(vector_page)];
                  l2b = pmap_get_l2_bucket(pmap, vector_page);
                  pcb->pcb_l1vec = l2b->l2b_phys | L1_C_PROTO |
                      L1_C_DOM(pmap->pm_domain) | L1_C_DOM(PMAP_DOMAIN_KERNEL);
          } else
                  pcb->pcb_pl1vec = NULL;
  }
  
  void
  pmap_activate(struct thread *td)
  {
          pmap_t pmap;
          struct pcb *pcb;
  
          pmap = vmspace_pmap(td->td_proc->p_vmspace);
          pcb = td->td_pcb;
  
          critical_enter();
          pmap_set_pcb_pagedir(pmap, pcb);
  
          if (td == curthread) {
                  u_int cur_dacr, cur_ttb;
  
                  __asm __volatile("mrc p15, 0, %0, c2, c0, 0" : "=r"(cur_ttb));
                  __asm __volatile("mrc p15, 0, %0, c3, c0, 0" : "=r"(cur_dacr));
  
                  cur_ttb &= ~(L1_TABLE_SIZE - 1);
  
                  if (cur_ttb == (u_int)pcb->pcb_pagedir &&
                      cur_dacr == pcb->pcb_dacr) {
                          /*
                           * No need to switch address spaces.
                           */
                          critical_exit();
                          return;
                  }
  
  
                  /*
                   * We MUST, I repeat, MUST fix up the L1 entry corresponding
                   * to 'vector_page' in the incoming L1 table before switching
                   * to it otherwise subsequent interrupts/exceptions (including
                   * domain faults!) will jump into hyperspace.
                   */
                  if (pcb->pcb_pl1vec) {
                          *pcb->pcb_pl1vec = pcb->pcb_l1vec;
                  }
  
                  cpu_domains(pcb->pcb_dacr);
                  cpu_setttb(pcb->pcb_pagedir);
          }
          critical_exit();
  }
  
  static int
  pmap_set_pt_cache_mode(pd_entry_t *kl1, vm_offset_t va)
  {
          pd_entry_t *pdep, pde;
          pt_entry_t *ptep, pte;
          vm_offset_t pa;
          int rv = 0;
  
          /*
           * Make sure the descriptor itself has the correct cache mode
           */
          pdep = &kl1[L1_IDX(va)];
          pde = *pdep;
  
          if (l1pte_section_p(pde)) {
                  if ((pde & L1_S_CACHE_MASK) != pte_l1_s_cache_mode_pt) {
                          *pdep = (pde & ~L1_S_CACHE_MASK) |
                              pte_l1_s_cache_mode_pt;
                          PTE_SYNC(pdep);
                          rv = 1;
                  }
          } else {
                  pa = (vm_paddr_t)(pde & L1_C_ADDR_MASK);
                  ptep = (pt_entry_t *)kernel_pt_lookup(pa);
                  if (ptep == NULL)
                          panic("pmap_bootstrap: No L2 for L2 @ va %p\n", ptep);
  
                  ptep = &ptep[l2pte_index(va)];
                  pte = *ptep;
                  if ((pte & L2_S_CACHE_MASK) != pte_l2_s_cache_mode_pt) {
                          *ptep = (pte & ~L2_S_CACHE_MASK) |
                              pte_l2_s_cache_mode_pt;
                          PTE_SYNC(ptep);
                          rv = 1;
                  }
          }
  
          return (rv);
  }
  
  static void
  pmap_alloc_specials(vm_offset_t *availp, int pages, vm_offset_t *vap,
      pt_entry_t **ptep)
  {
          vm_offset_t va = *availp;
          struct l2_bucket *l2b;
  
          if (ptep) {
                  l2b = pmap_get_l2_bucket(pmap_kernel(), va);
                  if (l2b == NULL)
                          panic("pmap_alloc_specials: no l2b for 0x%x", va);
  
                  *ptep = &l2b->l2b_kva[l2pte_index(va)];
          }
  
          *vap = va;
          *availp = va + (PAGE_SIZE * pages);
  }
  
  /*
   *      Bootstrap the system enough to run with virtual memory.
   *
   *      On the arm this is called after mapping has already been enabled
   *      and just syncs the pmap module with what has already been done.
   *      [We can't call it easily with mapping off since the kernel is not
   *      mapped with PA == VA, hence we would have to relocate every address
   *      from the linked base (virtual) address "KERNBASE" to the actual
   *      (physical) address starting relative to 0]
   */
  #define PMAP_STATIC_L2_SIZE 16
  
  void
  pmap_bootstrap(vm_offset_t firstaddr, struct pv_addr *l1pt)
  {
          static struct l1_ttable static_l1;
          static struct l2_dtable static_l2[PMAP_STATIC_L2_SIZE];
          struct l1_ttable *l1 = &static_l1;
          struct l2_dtable *l2;
          struct l2_bucket *l2b;
          pd_entry_t pde;
          pd_entry_t *kernel_l1pt = (pd_entry_t *)l1pt->pv_va;
          pt_entry_t *ptep;
          vm_paddr_t pa;
          vm_offset_t va;
          vm_size_t size;
          int l1idx, l2idx, l2next = 0;
  
          PDEBUG(1, printf("firstaddr = %08x, lastaddr = %08x\n",
              firstaddr, vm_max_kernel_address));
  
          virtual_avail = firstaddr;
          kernel_pmap->pm_l1 = l1;
          kernel_l1pa = l1pt->pv_pa;
  
          /*
           * Scan the L1 translation table created by initarm() and create
           * the required metadata for all valid mappings found in it.
           */
          for (l1idx = 0; l1idx < (L1_TABLE_SIZE / sizeof(pd_entry_t)); l1idx++) {
                  pde = kernel_l1pt[l1idx];
  
                  /*
                   * We're only interested in Coarse mappings.
                   * pmap_extract() can deal with section mappings without
                   * recourse to checking L2 metadata.
                   */
                  if ((pde & L1_TYPE_MASK) != L1_TYPE_C)
                          continue;
  
                  /*
                   * Lookup the KVA of this L2 descriptor table
                   */
                  pa = (vm_paddr_t)(pde & L1_C_ADDR_MASK);
                  ptep = (pt_entry_t *)kernel_pt_lookup(pa);
  
                  if (ptep == NULL) {
                          panic("pmap_bootstrap: No L2 for va 0x%x, pa 0x%lx",
                              (u_int)l1idx << L1_S_SHIFT, (long unsigned int)pa);
                  }
  
                  /*
                   * Fetch the associated L2 metadata structure.
                   * Allocate a new one if necessary.
                   */
                  if ((l2 = kernel_pmap->pm_l2[L2_IDX(l1idx)]) == NULL) {
                          if (l2next == PMAP_STATIC_L2_SIZE)
                                  panic("pmap_bootstrap: out of static L2s");
                          kernel_pmap->pm_l2[L2_IDX(l1idx)] = l2 =
                              &static_l2[l2next++];
                  }
  
                  /*
                   * One more L1 slot tracked...
                   */
                  l2->l2_occupancy++;
  
                  /*
                   * Fill in the details of the L2 descriptor in the
                   * appropriate bucket.
                   */
                  l2b = &l2->l2_bucket[L2_BUCKET(l1idx)];
                  l2b->l2b_kva = ptep;
                  l2b->l2b_phys = pa;
                  l2b->l2b_l1idx = l1idx;
  
                  /*
                   * Establish an initial occupancy count for this descriptor
                   */
                  for (l2idx = 0;
                      l2idx < (L2_TABLE_SIZE_REAL / sizeof(pt_entry_t));
                      l2idx++) {
                          if ((ptep[l2idx] & L2_TYPE_MASK) != L2_TYPE_INV) {
                                  l2b->l2b_occupancy++;
                          }
                  }
  
                  /*
                   * Make sure the descriptor itself has the correct cache mode.
                   * If not, fix it, but whine about the problem. Port-meisters
                   * should consider this a clue to fix up their initarm()
                   * function. :)
                   */
                  if (pmap_set_pt_cache_mode(kernel_l1pt, (vm_offset_t)ptep)) {
                          printf("pmap_bootstrap: WARNING! wrong cache mode for "
                              "L2 pte @ %p\n", ptep);
                  }
          }
  
  
          /*
           * Ensure the primary (kernel) L1 has the correct cache mode for
           * a page table. Bitch if it is not correctly set.
           */
          for (va = (vm_offset_t)kernel_l1pt;
              va < ((vm_offset_t)kernel_l1pt + L1_TABLE_SIZE); va += PAGE_SIZE) {
                  if (pmap_set_pt_cache_mode(kernel_l1pt, va))
                          printf("pmap_bootstrap: WARNING! wrong cache mode for "
                              "primary L1 @ 0x%x\n", va);
          }
  
          cpu_dcache_wbinv_all();
          cpu_l2cache_wbinv_all();
          cpu_tlb_flushID();
          cpu_cpwait();
  
          PMAP_LOCK_INIT(kernel_pmap);
          CPU_FILL(&kernel_pmap->pm_active);
          kernel_pmap->pm_domain = PMAP_DOMAIN_KERNEL;
          TAILQ_INIT(&kernel_pmap->pm_pvchunk);
  
          /*
           * Initialize the global pv list lock.
           */
          rw_init(&pvh_global_lock, "pmap pv global");
  
          /*
           * Reserve some special page table entries/VA space for temporary
           * mapping of pages.
           */
  
          pmap_alloc_specials(&virtual_avail, 1, &csrcp, &csrc_pte);
          pmap_set_pt_cache_mode(kernel_l1pt, (vm_offset_t)csrc_pte);
          pmap_alloc_specials(&virtual_avail, 1, &cdstp, &cdst_pte);
          pmap_set_pt_cache_mode(kernel_l1pt, (vm_offset_t)cdst_pte);
          size = ((vm_max_kernel_address - pmap_curmaxkvaddr) + L1_S_OFFSET) /
              L1_S_SIZE;
          pmap_alloc_specials(&virtual_avail,
              round_page(size * L2_TABLE_SIZE_REAL) / PAGE_SIZE,
              &pmap_kernel_l2ptp_kva, NULL);
  
          size = (size + (L2_BUCKET_SIZE - 1)) / L2_BUCKET_SIZE;
          pmap_alloc_specials(&virtual_avail,
              round_page(size * sizeof(struct l2_dtable)) / PAGE_SIZE,
              &pmap_kernel_l2dtable_kva, NULL);
  
          pmap_alloc_specials(&virtual_avail,
              1, (vm_offset_t*)&_tmppt, NULL);
          pmap_alloc_specials(&virtual_avail,
              MAXDUMPPGS, (vm_offset_t *)&crashdumpmap, NULL);
          SLIST_INIT(&l1_list);
          TAILQ_INIT(&l1_lru_list);
          mtx_init(&l1_lru_lock, "l1 list lock", NULL, MTX_DEF);
          pmap_init_l1(l1, kernel_l1pt);
          cpu_dcache_wbinv_all();
          cpu_l2cache_wbinv_all();
  
          virtual_avail = round_page(virtual_avail);
          virtual_end = vm_max_kernel_address;
          kernel_vm_end = pmap_curmaxkvaddr;
          arm_nocache_startaddr = vm_max_kernel_address;
          mtx_init(&cmtx, "TMP mappings mtx", NULL, MTX_DEF);
  
          pmap_set_pcb_pagedir(kernel_pmap, thread0.td_pcb);
  }
  
  /***************************************************
   * Pmap allocation/deallocation routines.
   ***************************************************/
  
  /*
   * Release any resources held by the given physical map.
   * Called when a pmap initialized by pmap_pinit is being released.
   * Should only be called if the map contains no valid mappings.
   */
  void
  pmap_release(pmap_t pmap)
  {
          struct pcb *pcb;
  
          cpu_idcache_wbinv_all();
          cpu_l2cache_wbinv_all();
          cpu_tlb_flushID();
          cpu_cpwait();
          if (vector_page < KERNBASE) {
                  struct pcb *curpcb = PCPU_GET(curpcb);
                  pcb = thread0.td_pcb;
                  if (pmap_is_current(pmap)) {
                          /*
                           * Frob the L1 entry corresponding to the vector
                           * page so that it contains the kernel pmap's domain
                           * number. This will ensure pmap_remove() does not
                           * pull the current vector page out from under us.
                           */
                          critical_enter();
                          *pcb->pcb_pl1vec = pcb->pcb_l1vec;
                          cpu_domains(pcb->pcb_dacr);
                          cpu_setttb(pcb->pcb_pagedir);
                          critical_exit();
                  }
                  pmap_remove(pmap, vector_page, vector_page + PAGE_SIZE);
                  /*
                   * Make sure cpu_switch(), et al, DTRT. This is safe to do
                   * since this process has no remaining mappings of its own.
                   */
                  curpcb->pcb_pl1vec = pcb->pcb_pl1vec;
                  curpcb->pcb_l1vec = pcb->pcb_l1vec;
                  curpcb->pcb_dacr = pcb->pcb_dacr;
                  curpcb->pcb_pagedir = pcb->pcb_pagedir;
  
          }
          pmap_free_l1(pmap);
  
          dprintf("pmap_release()\n");
  }
  
  
  
  /*
   * Helper function for pmap_grow_l2_bucket()
   */
  static __inline int
  pmap_grow_map(vm_offset_t va, pt_entry_t cache_mode, vm_paddr_t *pap)
  {
          struct l2_bucket *l2b;
          pt_entry_t *ptep;
          vm_paddr_t pa;
          struct vm_page *m;
  
          m = vm_page_alloc(NULL, 0, VM_ALLOC_NOOBJ | VM_ALLOC_WIRED);
          if (m == NULL)
                  return (1);
          pa = VM_PAGE_TO_PHYS(m);
  
          if (pap)
                  *pap = pa;
  
          l2b = pmap_get_l2_bucket(pmap_kernel(), va);
  
          ptep = &l2b->l2b_kva[l2pte_index(va)];
          *ptep = L2_S_PROTO | pa | cache_mode | L2_S_REF;
          pmap_set_prot(ptep, VM_PROT_READ | VM_PROT_WRITE, 0);
          PTE_SYNC(ptep);
  
          return (0);
  }
  
  /*
   * This is the same as pmap_alloc_l2_bucket(), except that it is only
   * used by pmap_growkernel().
   */
  static __inline struct l2_bucket *
  pmap_grow_l2_bucket(pmap_t pmap, vm_offset_t va)
  {
          struct l2_dtable *l2;
          struct l2_bucket *l2b;
          struct l1_ttable *l1;
          pd_entry_t *pl1pd;
          u_short l1idx;
          vm_offset_t nva;
  
          l1idx = L1_IDX(va);
  
          if ((l2 = pmap->pm_l2[L2_IDX(l1idx)]) == NULL) {
                  /*
                   * No mapping at this address, as there is
                   * no entry in the L1 table.
                   * Need to allocate a new l2_dtable.
                   */
                  nva = pmap_kernel_l2dtable_kva;
                  if ((nva & PAGE_MASK) == 0) {
                          /*
                           * Need to allocate a backing page
                           */
                          if (pmap_grow_map(nva, pte_l2_s_cache_mode, NULL))
                                  return (NULL);
                  }
  
                  l2 = (struct l2_dtable *)nva;
                  nva += sizeof(struct l2_dtable);
  
                  if ((nva & PAGE_MASK) < (pmap_kernel_l2dtable_kva &
                      PAGE_MASK)) {
                          /*
                           * The new l2_dtable straddles a page boundary.
                           * Map in another page to cover it.
                           */
                          if (pmap_grow_map(nva, pte_l2_s_cache_mode, NULL))
                                  return (NULL);
                  }
  
                  pmap_kernel_l2dtable_kva = nva;
  
                  /*
                   * Link it into the parent pmap
                   */
                  pmap->pm_l2[L2_IDX(l1idx)] = l2;
                  memset(l2, 0, sizeof(*l2));
          }
  
          l2b = &l2->l2_bucket[L2_BUCKET(l1idx)];
  
          /*
           * Fetch pointer to the L2 page table associated with the address.
           */
          if (l2b->l2b_kva == NULL) {
                  pt_entry_t *ptep;
  
                  /*
                   * No L2 page table has been allocated. Chances are, this
                   * is because we just allocated the l2_dtable, above.
                   */
                  nva = pmap_kernel_l2ptp_kva;
                  ptep = (pt_entry_t *)nva;
                  if ((nva & PAGE_MASK) == 0) {
                          /*
                           * Need to allocate a backing page
                           */
                          if (pmap_grow_map(nva, pte_l2_s_cache_mode_pt,
                              &pmap_kernel_l2ptp_phys))
                                  return (NULL);
                  }
                  memset(ptep, 0, L2_TABLE_SIZE_REAL);
                  l2->l2_occupancy++;
                  l2b->l2b_kva = ptep;
                  l2b->l2b_l1idx = l1idx;
                  l2b->l2b_phys = pmap_kernel_l2ptp_phys;
  
                  pmap_kernel_l2ptp_kva += L2_TABLE_SIZE_REAL;
                  pmap_kernel_l2ptp_phys += L2_TABLE_SIZE_REAL;
          }
  
          /* Distribute new L1 entry to all other L1s */
          SLIST_FOREACH(l1, &l1_list, l1_link) {
                          pl1pd = &l1->l1_kva[L1_IDX(va)];
                          *pl1pd = l2b->l2b_phys | L1_C_DOM(PMAP_DOMAIN_KERNEL) |
                              L1_C_PROTO;
                          PTE_SYNC(pl1pd);
          }
  
          return (l2b);
  }
  
  
  /*
   * grow the number of kernel page table entries, if needed
   */
  void
  pmap_growkernel(vm_offset_t addr)
  {
          pmap_t kpmap = pmap_kernel();
  
          if (addr <= pmap_curmaxkvaddr)
                  return;         /* we are OK */
  
          /*
           * whoops!   we need to add kernel PTPs
           */
  
          /* Map 1MB at a time */
          for (; pmap_curmaxkvaddr < addr; pmap_curmaxkvaddr += L1_S_SIZE)
                  pmap_grow_l2_bucket(kpmap, pmap_curmaxkvaddr);
  
          /*
           * flush out the cache, expensive but growkernel will happen so
           * rarely
           */
          cpu_dcache_wbinv_all();
          cpu_l2cache_wbinv_all();
          cpu_tlb_flushD();
          cpu_cpwait();
          kernel_vm_end = pmap_curmaxkvaddr;
  }
  
  /*
   * Returns TRUE if the given page is mapped individually or as part of
   * a 1MB section.  Otherwise, returns FALSE.
   */
  boolean_t
  pmap_page_is_mapped(vm_page_t m)
  {
          boolean_t rv;
  
          if ((m->oflags & VPO_UNMANAGED) != 0)
                  return (FALSE);
          rw_wlock(&pvh_global_lock);
          rv = !TAILQ_EMPTY(&m->md.pv_list) ||
              ((m->flags & PG_FICTITIOUS) == 0 &&
              !TAILQ_EMPTY(&pa_to_pvh(VM_PAGE_TO_PHYS(m))->pv_list));
          rw_wunlock(&pvh_global_lock);
          return (rv);
  }
  
  /*
   * Remove all pages from specified address space
   * this aids process exit speeds.  Also, this code
   * is special cased for current process only, but
   * can have the more generic (and slightly slower)
   * mode enabled.  This is much faster than pmap_remove
   * in the case of running down an entire address space.
   */
  void
  pmap_remove_pages(pmap_t pmap)
  {
          struct pv_entry *pv;
          struct l2_bucket *l2b = NULL;
          struct pv_chunk *pc, *npc;
          struct md_page *pvh;
          pd_entry_t *pl1pd, l1pd;
          pt_entry_t *ptep;
          vm_page_t m, mt;
          vm_offset_t va;
          uint32_t inuse, bitmask;
          int allfree, bit, field, idx;
   
          rw_wlock(&pvh_global_lock);
          PMAP_LOCK(pmap);
  
          TAILQ_FOREACH_SAFE(pc, &pmap->pm_pvchunk, pc_list, npc) {
                  allfree = 1;
                  for (field = 0; field < _NPCM; field++) {
                          inuse = ~pc->pc_map[field] & pc_freemask[field];
                          while (inuse != 0) {
                                  bit = ffs(inuse) - 1;
                                  bitmask = 1ul << bit;
                                  idx = field * sizeof(inuse) * NBBY + bit;
                                  pv = &pc->pc_pventry[idx];
                                  va = pv->pv_va;
                                  inuse &= ~bitmask;
                                  if (pv->pv_flags & PVF_WIRED) {
                                          /* Cannot remove wired pages now. */
                                          allfree = 0;
                                          continue;
                                  }
                                  pl1pd = &pmap->pm_l1->l1_kva[L1_IDX(va)];
                                  l1pd = *pl1pd;
                                  l2b = pmap_get_l2_bucket(pmap, va);
                                  if ((l1pd & L1_TYPE_MASK) == L1_S_PROTO) {
                                          pvh = pa_to_pvh(l1pd & L1_S_FRAME);
                                          TAILQ_REMOVE(&pvh->pv_list, pv, pv_list);
                                          if (TAILQ_EMPTY(&pvh->pv_list)) {
                                                  m = PHYS_TO_VM_PAGE(l1pd & L1_S_FRAME);
                                                  KASSERT((vm_offset_t)m >= KERNBASE,
                                                      ("Trying to access non-existent page "
                                                       "va %x l1pd %x", trunc_1mpage(va), l1pd));
                                                  for (mt = m; mt < &m[L2_PTE_NUM_TOTAL]; mt++) {
                                                          if (TAILQ_EMPTY(&mt->md.pv_list))
                                                                  vm_page_aflag_clear(mt, PGA_WRITEABLE);
                                                  }
                                          }
                                          if (l2b != NULL) {
                                                  KASSERT(l2b->l2b_occupancy == L2_PTE_NUM_TOTAL,
                                                      ("pmap_remove_pages: l2_bucket occupancy error"));
                                                  pmap_free_l2_bucket(pmap, l2b, L2_PTE_NUM_TOTAL);
                                          }
                                          pmap->pm_stats.resident_count -= L2_PTE_NUM_TOTAL;
                                          *pl1pd = 0;
                                          PTE_SYNC(pl1pd);
                                  } else {
                                          KASSERT(l2b != NULL,
                                              ("No L2 bucket in pmap_remove_pages"));
                                          ptep = &l2b->l2b_kva[l2pte_index(va)];
                                          m = PHYS_TO_VM_PAGE(l2pte_pa(*ptep));
                                          KASSERT((vm_offset_t)m >= KERNBASE,
                                              ("Trying to access non-existent page "
                                               "va %x pte %x", va, *ptep));
                                          TAILQ_REMOVE(&m->md.pv_list, pv, pv_list);
                                          if (TAILQ_EMPTY(&m->md.pv_list) &&
                                              (m->flags & PG_FICTITIOUS) == 0) {
                                                  pvh = pa_to_pvh(l2pte_pa(*ptep));
                                                  if (TAILQ_EMPTY(&pvh->pv_list))
                                                          vm_page_aflag_clear(m, PGA_WRITEABLE);
                                          }
                                          *ptep = 0;
                                          PTE_SYNC(ptep);
                                          pmap_free_l2_bucket(pmap, l2b, 1);
                                          pmap->pm_stats.resident_count--;
                                  }
  
                                  /* Mark free */
                                  PV_STAT(pv_entry_frees++);
                                  PV_STAT(pv_entry_spare++);
                                  pv_entry_count--;
                                  pc->pc_map[field] |= bitmask;
                          }
                  }
                  if (allfree) {
                          TAILQ_REMOVE(&pmap->pm_pvchunk, pc, pc_list);
                          pmap_free_pv_chunk(pc);
                  }
  
          }
  
          rw_wunlock(&pvh_global_lock);
          cpu_tlb_flushID();
          cpu_cpwait();
          PMAP_UNLOCK(pmap);
  }
  
  
  /***************************************************
   * Low level mapping routines.....
   ***************************************************/
  
  #ifdef ARM_HAVE_SUPERSECTIONS
  /* Map a super section into the KVA. */
  
  void
  pmap_kenter_supersection(vm_offset_t va, uint64_t pa, int flags)
  {
          pd_entry_t pd = L1_S_PROTO | L1_S_SUPERSEC | (pa & L1_SUP_FRAME) |
              (((pa >> 32) & 0xf) << 20) | L1_S_PROT(PTE_KERNEL,
              VM_PROT_READ|VM_PROT_WRITE|VM_PROT_EXECUTE) |
              L1_S_DOM(PMAP_DOMAIN_KERNEL);
          struct l1_ttable *l1;
          vm_offset_t va0, va_end;
  
          KASSERT(((va | pa) & L1_SUP_OFFSET) == 0,
              ("Not a valid super section mapping"));
          if (flags & SECTION_CACHE)
                  pd |= pte_l1_s_cache_mode;
          else if (flags & SECTION_PT)
                  pd |= pte_l1_s_cache_mode_pt;
  
          va0 = va & L1_SUP_FRAME;
          va_end = va + L1_SUP_SIZE;
          SLIST_FOREACH(l1, &l1_list, l1_link) {
                  va = va0;
                  for (; va < va_end; va += L1_S_SIZE) {
                          l1->l1_kva[L1_IDX(va)] = pd;
                          PTE_SYNC(&l1->l1_kva[L1_IDX(va)]);
                  }
          }
  }
  #endif
  
  /* Map a section into the KVA. */
  
  void
  pmap_kenter_section(vm_offset_t va, vm_offset_t pa, int flags)
  {
          pd_entry_t pd = L1_S_PROTO | pa | L1_S_PROT(PTE_KERNEL,
              VM_PROT_READ|VM_PROT_WRITE|VM_PROT_EXECUTE) | L1_S_REF |
              L1_S_DOM(PMAP_DOMAIN_KERNEL);
          struct l1_ttable *l1;
  
          KASSERT(((va | pa) & L1_S_OFFSET) == 0,
              ("Not a valid section mapping"));
          if (flags & SECTION_CACHE)
                  pd |= pte_l1_s_cache_mode;
          else if (flags & SECTION_PT)
                  pd |= pte_l1_s_cache_mode_pt;
  
          SLIST_FOREACH(l1, &l1_list, l1_link) {
                  l1->l1_kva[L1_IDX(va)] = pd;
                  PTE_SYNC(&l1->l1_kva[L1_IDX(va)]);
          }
  }
  
  /*
   * Make a temporary mapping for a physical address.  This is only intended
   * to be used for panic dumps.
   */
  void *
  pmap_kenter_temp(vm_paddr_t pa, int i)
  {
          vm_offset_t va;
  
          va = (vm_offset_t)crashdumpmap + (i * PAGE_SIZE);
          pmap_kenter(va, pa);
          return ((void *)crashdumpmap);
  }
  
  /*
   * add a wired page to the kva
   * note that in order for the mapping to take effect -- you
   * should do a invltlb after doing the pmap_kenter...
   */
  static PMAP_INLINE void
  pmap_kenter_internal(vm_offset_t va, vm_offset_t pa, int flags)
  {
          struct l2_bucket *l2b;
          pt_entry_t *ptep;
          pt_entry_t opte;
  
          PDEBUG(1, printf("pmap_kenter: va = %08x, pa = %08x\n",
              (uint32_t) va, (uint32_t) pa));
  
  
          l2b = pmap_get_l2_bucket(pmap_kernel(), va);
          if (l2b == NULL)
                  l2b = pmap_grow_l2_bucket(pmap_kernel(), va);
          KASSERT(l2b != NULL, ("No L2 Bucket"));
  
          ptep = &l2b->l2b_kva[l2pte_index(va)];
          opte = *ptep;
          if (l2pte_valid(opte)) {
                  cpu_tlb_flushD_SE(va);
                  cpu_cpwait();
          } else {
                  if (opte == 0)
                          l2b->l2b_occupancy++;
          }
  
          if (flags & KENTER_CACHE) {
                  *ptep = L2_S_PROTO | pa | pte_l2_s_cache_mode | L2_S_REF;
                  pmap_set_prot(ptep, VM_PROT_READ | VM_PROT_WRITE,
                      flags & KENTER_USER);
          } else {
                  *ptep = L2_S_PROTO | pa | L2_S_REF;
                  pmap_set_prot(ptep, VM_PROT_READ|VM_PROT_WRITE|VM_PROT_EXECUTE,
                      0);
          }
  
          PDEBUG(1, printf("pmap_kenter: pte = %08x, opte = %08x, npte = %08x\n",
              (uint32_t) ptep, opte, *ptep));
          PTE_SYNC(ptep);
          cpu_cpwait();
  }
  
  void
  pmap_kenter(vm_offset_t va, vm_paddr_t pa)
  {
          pmap_kenter_internal(va, pa, KENTER_CACHE);
  }
  
  void
  pmap_kenter_nocache(vm_offset_t va, vm_paddr_t pa)
  {
  
          pmap_kenter_internal(va, pa, 0);
  }
  
  void
  pmap_kenter_user(vm_offset_t va, vm_paddr_t pa)
  {
  
          pmap_kenter_internal(va, pa, KENTER_CACHE|KENTER_USER);
          /*
           * Call pmap_fault_fixup now, to make sure we'll have no exception
           * at the first use of the new address, or bad things will happen,
           * as we use one of these addresses in the exception handlers.
           */
          pmap_fault_fixup(pmap_kernel(), va, VM_PROT_READ|VM_PROT_WRITE, 1);
  }
  
  vm_paddr_t
  pmap_kextract(vm_offset_t va)
  {
  
          return (pmap_extract_locked(kernel_pmap, va));
  }
  
  /*
   * remove a page from the kernel pagetables
   */
  void
  pmap_kremove(vm_offset_t va)
  {
          struct l2_bucket *l2b;
          pt_entry_t *ptep, opte;
  
          l2b = pmap_get_l2_bucket(pmap_kernel(), va);
          if (!l2b)
                  return;
          KASSERT(l2b != NULL, ("No L2 Bucket"));
          ptep = &l2b->l2b_kva[l2pte_index(va)];
          opte = *ptep;
          if (l2pte_valid(opte)) {
                  va = va & ~PAGE_MASK;
                  cpu_tlb_flushD_SE(va);
                  cpu_cpwait();
                  *ptep = 0;
                  PTE_SYNC(ptep);
          }
  }
  
  
  /*
   *      Used to map a range of physical addresses into kernel
   *      virtual address space.
   *
   *      The value passed in '*virt' is a suggested virtual address for
   *      the mapping. Architectures which can support a direct-mapped
   *      physical to virtual region can return the appropriate address
   *      within that region, leaving '*virt' unchanged. Other
   *      architectures should map the pages starting at '*virt' and
   *      update '*virt' with the first usable address after the mapped
   *      region.
   */
  vm_offset_t
  pmap_map(vm_offset_t *virt, vm_offset_t start, vm_offset_t end, int prot)
  {
          vm_offset_t sva = *virt;
          vm_offset_t va = sva;
  
          PDEBUG(1, printf("pmap_map: virt = %08x, start = %08x, end = %08x, "
              "prot = %d\n", (uint32_t) *virt, (uint32_t) start, (uint32_t) end,
              prot));
  
          while (start < end) {
                  pmap_kenter(va, start);
                  va += PAGE_SIZE;
                  start += PAGE_SIZE;
          }
          *virt = va;
          return (sva);
  }
  
  /*
   * Add a list of wired pages to the kva
   * this routine is only used for temporary
   * kernel mappings that do not need to have
   * page modification or references recorded.
   * Note that old mappings are simply written
   * over.  The page *must* be wired.
   */
  void
  pmap_qenter(vm_offset_t va, vm_page_t *m, int count)
  {
          int i;
  
          for (i = 0; i < count; i++) {
                  pmap_kenter_internal(va, VM_PAGE_TO_PHYS(m[i]),
                      KENTER_CACHE);
                  va += PAGE_SIZE;
          }
  }
  
  
  /*
   * this routine jerks page mappings from the
   * kernel -- it is meant only for temporary mappings.
   */
  void
  pmap_qremove(vm_offset_t va, int count)
  {
          int i;
  
          for (i = 0; i < count; i++) {
                  if (vtophys(va))
                          pmap_kremove(va);
  
                  va += PAGE_SIZE;
          }
  }
  
  
  /*
   * pmap_object_init_pt preloads the ptes for a given object
   * into the specified pmap.  This eliminates the blast of soft
   * faults on process startup and immediately after an mmap.
   */
  void
  pmap_object_init_pt(pmap_t pmap, vm_offset_t addr, vm_object_t object,
      vm_pindex_t pindex, vm_size_t size)
  {
  
          VM_OBJECT_ASSERT_WLOCKED(object);
          KASSERT(object->type == OBJT_DEVICE || object->type == OBJT_SG,
              ("pmap_object_init_pt: non-device object"));
  }
  
  
  /*
   *      pmap_is_prefaultable:
   *
   *      Return whether or not the specified virtual address is elgible
   *      for prefault.
   */
  boolean_t
  pmap_is_prefaultable(pmap_t pmap, vm_offset_t addr)
  {
          pd_entry_t *pdep;
          pt_entry_t *ptep;
  
          if (!pmap_get_pde_pte(pmap, addr, &pdep, &ptep))
                  return (FALSE);
          KASSERT((pdep != NULL && (l1pte_section_p(*pdep) || ptep != NULL)),
              ("Valid mapping but no pte ?"));
          if (*pdep != 0 && !l1pte_section_p(*pdep))
                  if (*ptep == 0)
                          return (TRUE);
          return (FALSE);
  }
  
  /*
   * Fetch pointers to the PDE/PTE for the given pmap/VA pair.
   * Returns TRUE if the mapping exists, else FALSE.
   *
   * NOTE: This function is only used by a couple of arm-specific modules.
   * It is not safe to take any pmap locks here, since we could be right
   * in the middle of debugging the pmap anyway...
   *
   * It is possible for this routine to return FALSE even though a valid
   * mapping does exist. This is because we don't lock, so the metadata
   * state may be inconsistent.
   *
   * NOTE: We can return a NULL *ptp in the case where the L1 pde is
   * a "section" mapping.
   */
  boolean_t
  pmap_get_pde_pte(pmap_t pmap, vm_offset_t va, pd_entry_t **pdp,
      pt_entry_t **ptp)
  {
          struct l2_dtable *l2;
          pd_entry_t *pl1pd, l1pd;
          pt_entry_t *ptep;
          u_short l1idx;
  
          if (pmap->pm_l1 == NULL)
                  return (FALSE);
  
          l1idx = L1_IDX(va);
          *pdp = pl1pd = &pmap->pm_l1->l1_kva[l1idx];
          l1pd = *pl1pd;
  
          if (l1pte_section_p(l1pd)) {
                  *ptp = NULL;
                  return (TRUE);
          }
  
          if (pmap->pm_l2 == NULL)
                  return (FALSE);
  
          l2 = pmap->pm_l2[L2_IDX(l1idx)];
  
          if (l2 == NULL ||
              (ptep = l2->l2_bucket[L2_BUCKET(l1idx)].l2b_kva) == NULL) {
                  return (FALSE);
          }
  
          *ptp = &ptep[l2pte_index(va)];
          return (TRUE);
  }
  
  /*
   *      Routine:        pmap_remove_all
   *      Function:
   *              Removes this physical page from
   *              all physical maps in which it resides.
   *              Reflects back modify bits to the pager.
   *
   *      Notes:
   *              Original versions of this routine were very
   *              inefficient because they iteratively called
   *              pmap_remove (slow...)
   */
  void
  pmap_remove_all(vm_page_t m)
  {
          struct md_page *pvh;
          pv_entry_t pv;
          pmap_t pmap;
          pt_entry_t *ptep;
          struct l2_bucket *l2b;
          boolean_t flush = FALSE;
          pmap_t curpmap;
          u_int is_exec = 0;
  
          KASSERT((m->oflags & VPO_UNMANAGED) == 0,
              ("pmap_remove_all: page %p is not managed", m));
          rw_wlock(&pvh_global_lock);
          if ((m->flags & PG_FICTITIOUS) != 0)
                  goto small_mappings;
          pvh = pa_to_pvh(VM_PAGE_TO_PHYS(m));
          while ((pv = TAILQ_FIRST(&pvh->pv_list)) != NULL) {
                  pmap = PV_PMAP(pv);
                  PMAP_LOCK(pmap);
                  pd_entry_t *pl1pd;
                  pl1pd = &pmap->pm_l1->l1_kva[L1_IDX(pv->pv_va)];
                  KASSERT((*pl1pd & L1_TYPE_MASK) == L1_S_PROTO,
                      ("pmap_remove_all: valid section mapping expected"));
                  (void)pmap_demote_section(pmap, pv->pv_va);
                  PMAP_UNLOCK(pmap);
          }
  small_mappings:
          curpmap = vmspace_pmap(curproc->p_vmspace);
          while ((pv = TAILQ_FIRST(&m->md.pv_list)) != NULL) {
                  pmap = PV_PMAP(pv);
                  if (flush == FALSE && (pmap == curpmap ||
                      pmap == pmap_kernel()))
                          flush = TRUE;
  
                  PMAP_LOCK(pmap);
                  l2b = pmap_get_l2_bucket(pmap, pv->pv_va);
                  KASSERT(l2b != NULL, ("No l2 bucket"));
                  ptep = &l2b->l2b_kva[l2pte_index(pv->pv_va)];
                  is_exec |= PTE_BEEN_EXECD(*ptep);
                  *ptep = 0;
                  if (pmap_is_current(pmap))
                          PTE_SYNC(ptep);
                  pmap_free_l2_bucket(pmap, l2b, 1);
                  pmap->pm_stats.resident_count--;
                  TAILQ_REMOVE(&m->md.pv_list, pv, pv_list);
                  if (pv->pv_flags & PVF_WIRED)
                          pmap->pm_stats.wired_count--;
                  pmap_free_pv_entry(pmap, pv);
                  PMAP_UNLOCK(pmap);
          }
  
          if (flush) {
                  if (is_exec)
                          cpu_tlb_flushID();
                  else
                          cpu_tlb_flushD();
          }
          vm_page_aflag_clear(m, PGA_WRITEABLE);
          rw_wunlock(&pvh_global_lock);
  }
  
  int
  pmap_change_attr(vm_offset_t sva, vm_size_t len, int mode)
  {
          vm_offset_t base, offset, tmpva;
          vm_size_t size;
          struct l2_bucket *l2b;
          pt_entry_t *ptep, pte;
          vm_offset_t next_bucket;
  
          PMAP_LOCK(kernel_pmap);
  
          base = trunc_page(sva);
          offset = sva & PAGE_MASK;
          size = roundup(offset + len, PAGE_SIZE);
  
  #ifdef checkit
          /*
           * Only supported on kernel virtual addresses, including the direct
           * map but excluding the recursive map.
           */
          if (base < DMAP_MIN_ADDRESS) {
                  PMAP_UNLOCK(kernel_pmap);
                  return (EINVAL);
          }
  #endif
          for (tmpva = base; tmpva < base + size; ) {
                  next_bucket = L2_NEXT_BUCKET(tmpva);
                  if (next_bucket > base + size)
                          next_bucket = base + size;
  
                  l2b = pmap_get_l2_bucket(kernel_pmap, tmpva);
                  if (l2b == NULL) {
                          tmpva = next_bucket;
                          continue;
                  }
  
                  ptep = &l2b->l2b_kva[l2pte_index(tmpva)];
  
                  if (*ptep == 0) {
                          PMAP_UNLOCK(kernel_pmap);
                          return(EINVAL);
                  }
  
                  pte = *ptep &~ L2_S_CACHE_MASK;
                  cpu_idcache_wbinv_range(tmpva, PAGE_SIZE);
                  pmap_l2cache_wbinv_range(tmpva, pte & L2_S_FRAME, PAGE_SIZE);
                  *ptep = pte;
                  cpu_tlb_flushID_SE(tmpva);
  
                  dprintf("%s: for va:%x ptep:%x pte:%x\n",
                      __func__, tmpva, (uint32_t)ptep, pte);
                  tmpva += PAGE_SIZE;
          }
  
          PMAP_UNLOCK(kernel_pmap);
  
          return (0);
  }
  
  /*
   *      Set the physical protection on the
   *      specified range of this map as requested.
   */
  void
  pmap_protect(pmap_t pmap, vm_offset_t sva, vm_offset_t eva, vm_prot_t prot)
  {
          struct l2_bucket *l2b;
          struct md_page *pvh;
          struct pv_entry *pve;
          pd_entry_t *pl1pd, l1pd;
          pt_entry_t *ptep, pte;
          vm_offset_t next_bucket;
          u_int is_exec, is_refd;
          int flush;
  
          if ((prot & VM_PROT_READ) == 0) {
                  pmap_remove(pmap, sva, eva);
                  return;
          }
  
          if (prot & VM_PROT_WRITE) {
                  /*
                   * If this is a read->write transition, just ignore it and let
                   * vm_fault() take care of it later.
                   */
                  return;
          }
  
          rw_wlock(&pvh_global_lock);
          PMAP_LOCK(pmap);
  
          /*
           * OK, at this point, we know we're doing write-protect operation.
           * If the pmap is active, write-back the range.
           */
  
          flush = ((eva - sva) >= (PAGE_SIZE * 4)) ? 0 : -1;
          is_exec = is_refd = 0;
  
          while (sva < eva) {
                  next_bucket = L2_NEXT_BUCKET(sva);
                  /*
                   * Check for large page.
                   */
                  pl1pd = &pmap->pm_l1->l1_kva[L1_IDX(sva)];
                  l1pd = *pl1pd;
                  if ((l1pd & L1_TYPE_MASK) == L1_S_PROTO) {
                          KASSERT(pmap != pmap_kernel(),
                              ("pmap_protect: trying to modify "
                              "kernel section protections"));
                          /*
                           * Are we protecting the entire large page? If not,
                           * demote the mapping and fall through.
                           */
                          if (sva + L1_S_SIZE == L2_NEXT_BUCKET(sva) &&
                              eva >= L2_NEXT_BUCKET(sva)) {
                                  l1pd &= ~(L1_S_PROT_MASK | L1_S_XN);
                                  if (!(prot & VM_PROT_EXECUTE))
                                          *pl1pd |= L1_S_XN;
                                  /*
                                   * At this point we are always setting
                                   * write-protect bit.
                                   */
                                  l1pd |= L1_S_APX;
                                  /* All managed superpages are user pages. */
                                  l1pd |= L1_S_PROT_U;
                                  *pl1pd = l1pd;
                                  PTE_SYNC(pl1pd);
                                  pvh = pa_to_pvh(l1pd & L1_S_FRAME);
                                  pve = pmap_find_pv(pvh, pmap,
                                      trunc_1mpage(sva));
                                  pve->pv_flags &= ~PVF_WRITE;
                                  sva = next_bucket;
                                  continue;
                          } else if (!pmap_demote_section(pmap, sva)) {
                                  /* The large page mapping was destroyed. */
                                  sva = next_bucket;
                                  continue;
                          }
                  }
                  if (next_bucket > eva)
                          next_bucket = eva;
                  l2b = pmap_get_l2_bucket(pmap, sva);
                  if (l2b == NULL) {
                          sva = next_bucket;
                          continue;
                  }
  
                  ptep = &l2b->l2b_kva[l2pte_index(sva)];
  
                  while (sva < next_bucket) {
                          if ((pte = *ptep) != 0 && L2_S_WRITABLE(pte)) {
                                  struct vm_page *m;
  
                                  m = PHYS_TO_VM_PAGE(l2pte_pa(pte));
                                  pmap_set_prot(ptep, prot,
                                      !(pmap == pmap_kernel()));
                                  PTE_SYNC(ptep);
  
                                  pmap_modify_pv(m, pmap, sva, PVF_WRITE, 0);
  
                                  if (flush >= 0) {
                                          flush++;
                                          is_exec |= PTE_BEEN_EXECD(pte);
                                          is_refd |= PTE_BEEN_REFD(pte);
                                  } else {
                                          if (PTE_BEEN_EXECD(pte))
                                                  cpu_tlb_flushID_SE(sva);
                                          else if (PTE_BEEN_REFD(pte))
                                                  cpu_tlb_flushD_SE(sva);
                                  }
                          }
  
                          sva += PAGE_SIZE;
                          ptep++;
                  }
          }
  
  
          if (flush) {
                  if (is_exec)
                          cpu_tlb_flushID();
                  else
                  if (is_refd)
                          cpu_tlb_flushD();
          }
          rw_wunlock(&pvh_global_lock);
  
          PMAP_UNLOCK(pmap);
  }
  
  
  /*
   *      Insert the given physical page (p) at
   *      the specified virtual address (v) in the
   *      target physical map with the protection requested.
   *
   *      If specified, the page will be wired down, meaning
   *      that the related pte can not be reclaimed.
   *
   *      NB:  This is the only routine which MAY NOT lazy-evaluate
   *      or lose information.  That is, this routine must actually
   *      insert this page into the given map NOW.
   */
  
  void
  pmap_enter(pmap_t pmap, vm_offset_t va, vm_prot_t access, vm_page_t m,
      vm_prot_t prot, boolean_t wired)
  {
  
          rw_wlock(&pvh_global_lock);
          PMAP_LOCK(pmap);
          pmap_enter_locked(pmap, va, access, m, prot, wired, M_WAITOK);
          PMAP_UNLOCK(pmap);
          rw_wunlock(&pvh_global_lock);
  }
  
  /*
   *      The pvh global and pmap locks must be held.
   */
  static void
  pmap_enter_locked(pmap_t pmap, vm_offset_t va, vm_prot_t access, vm_page_t m,
      vm_prot_t prot, boolean_t wired, int flags)
  {
          struct l2_bucket *l2b = NULL;
          struct vm_page *om;
          struct pv_entry *pve = NULL;
          pd_entry_t *pl1pd, l1pd;
          pt_entry_t *ptep, npte, opte;
          u_int nflags;
          u_int is_exec, is_refd;
          vm_paddr_t pa;
          u_char user;
  
          PMAP_ASSERT_LOCKED(pmap);
          rw_assert(&pvh_global_lock, RA_WLOCKED);
          if (va == vector_page) {
                  pa = systempage.pv_pa;
                  m = NULL;
          } else {
                  KASSERT((m->oflags & VPO_UNMANAGED) != 0 ||
                      vm_page_xbusied(m) || (flags & M_NOWAIT) != 0,
                      ("pmap_enter_locked: page %p is not busy", m));
                  pa = VM_PAGE_TO_PHYS(m);
          }
  
          pl1pd = &pmap->pm_l1->l1_kva[L1_IDX(va)];
          if ((*pl1pd & L1_TYPE_MASK) == L1_S_PROTO)
                  panic("pmap_enter_locked: attempt pmap_enter_on 1MB page");
  
          user = 0;
          /*
           * Make sure userland mappings get the right permissions
           */
          if (pmap != pmap_kernel() && va != vector_page)
                  user = 1;
  
          nflags = 0;
  
          if (prot & VM_PROT_WRITE)
                  nflags |= PVF_WRITE;
          if (wired)
                  nflags |= PVF_WIRED;
  
          PDEBUG(1, printf("pmap_enter: pmap = %08x, va = %08x, m = %08x, "
              "prot = %x, wired = %x\n", (uint32_t) pmap, va, (uint32_t) m,
              prot, wired));
  
          if (pmap == pmap_kernel()) {
                  l2b = pmap_get_l2_bucket(pmap, va);
                  if (l2b == NULL)
                          l2b = pmap_grow_l2_bucket(pmap, va);
          } else {
  do_l2b_alloc:
                  l2b = pmap_alloc_l2_bucket(pmap, va);
                  if (l2b == NULL) {
                          if (flags & M_WAITOK) {
                                  PMAP_UNLOCK(pmap);
                                  rw_wunlock(&pvh_global_lock);
                                  VM_WAIT;
                                  rw_wlock(&pvh_global_lock);
                                  PMAP_LOCK(pmap);
                                  goto do_l2b_alloc;
                          }
                          return;
                  }
          }
  
          ptep = &l2b->l2b_kva[l2pte_index(va)];
  
          opte = *ptep;
          npte = pa;
          is_exec = is_refd = 0;
  
          if (opte) {
                  if (l2pte_pa(opte) == pa) {
                          /*
                           * We're changing the attrs of an existing mapping.
                           */
                          if (m != NULL)
                                  pmap_modify_pv(m, pmap, va,
                                      PVF_WRITE | PVF_WIRED, nflags);
                          is_exec |= PTE_BEEN_EXECD(opte);
                          is_refd |= PTE_BEEN_REFD(opte);
                          goto validate;
                  }
                  if ((om = PHYS_TO_VM_PAGE(l2pte_pa(opte)))) {
                          /*
                           * Replacing an existing mapping with a new one.
                           * It is part of our managed memory so we
                           * must remove it from the PV list
                           */
                          if ((pve = pmap_remove_pv(om, pmap, va))) {
                                  is_exec |= PTE_BEEN_EXECD(opte);
                                  is_refd |= PTE_BEEN_REFD(opte);
                  
                                  if (m && ((m->oflags & VPO_UNMANAGED)))
                                          pmap_free_pv_entry(pmap, pve);
                          }
                  }
  
          } else {
                  /*
                   * Keep the stats up to date
                   */
                  l2b->l2b_occupancy++;
                  pmap->pm_stats.resident_count++;
          }
  
          /*
           * Enter on the PV list if part of our managed memory.
           */
          if ((m && !(m->oflags & VPO_UNMANAGED))) {
                  if ((!pve) && (pve = pmap_get_pv_entry(pmap, FALSE)) == NULL)
                          panic("pmap_enter: no pv entries");
  
                  KASSERT(va < kmi.clean_sva || va >= kmi.clean_eva,
                  ("pmap_enter: managed mapping within the clean submap"));
                  KASSERT(pve != NULL, ("No pv"));
                  pmap_enter_pv(m, pve, pmap, va, nflags);
          }
  
  validate:
          /* Make the new PTE valid */
          npte |= L2_S_PROTO;
  #ifdef SMP
          npte |= L2_SHARED;
  #endif
          /* Set defaults first - kernel read access */
          npte |= L2_APX;
          npte |= L2_S_PROT_R;
          /* Set "referenced" flag */
          npte |= L2_S_REF;
  
          /* Now tune APs as desired */
          if (user)
                  npte |= L2_S_PROT_U;
          /*
           * If this is not a vector_page
           * then continue setting mapping parameters
           */
          if (m != NULL) {
                  if (prot & (VM_PROT_ALL)) {
                          if ((m->oflags & VPO_UNMANAGED) == 0)
                                  vm_page_aflag_set(m, PGA_REFERENCED);
                  } else {
                          /*
                           * Need to do page referenced emulation.
                           */
                          npte &= ~L2_S_REF;
                  }
  
                  if (prot & VM_PROT_WRITE) {
                          /*
                           * Enable write permission if the access type
                           * indicates write intention. Emulate modified
                           * bit otherwise.
                           */
                          if ((access & VM_PROT_WRITE) != 0)
                                  npte &= ~(L2_APX);
  
                          if ((m->oflags & VPO_UNMANAGED) == 0) {
                                  vm_page_aflag_set(m, PGA_WRITEABLE);
                                  /*
                                   * The access type and permissions indicate 
                                   * that the page will be written as soon as
                                   * returned from fault service.
                                   * Mark it dirty from the outset.
                                   */
                                  if ((access & VM_PROT_WRITE) != 0)
                                          vm_page_dirty(m);
                          }
                  }
                  if (!(prot & VM_PROT_EXECUTE))
                          npte |= L2_XN;
  
                  if (m->md.pv_memattr != VM_MEMATTR_UNCACHEABLE)
                          npte |= pte_l2_s_cache_mode;
          }
  
          CTR5(KTR_PMAP,"enter: pmap:%p va:%x prot:%x pte:%x->%x",
              pmap, va, prot, opte, npte);
          /*
           * If this is just a wiring change, the two PTEs will be
           * identical, so there's no need to update the page table.
           */
          if (npte != opte) {
                  boolean_t is_cached = pmap_is_current(pmap);
  
                  *ptep = npte;
                  PTE_SYNC(ptep);
                  if (is_cached) {
                          /*
                           * We only need to frob the cache/tlb if this pmap
                           * is current
                           */
                          if (L1_IDX(va) != L1_IDX(vector_page) &&
                              l2pte_valid(npte)) {
                                  /*
                                   * This mapping is likely to be accessed as
                                   * soon as we return to userland. Fix up the
                                   * L1 entry to avoid taking another
                                   * page/domain fault.
                                   */
                                  l1pd = l2b->l2b_phys |
                                      L1_C_DOM(pmap->pm_domain) | L1_C_PROTO;
                                  if (*pl1pd != l1pd) {
                                          *pl1pd = l1pd;
                                          PTE_SYNC(pl1pd);
                                  }
                          }
                  }
  
                  if (is_exec)
                          cpu_tlb_flushID_SE(va);
                  else if (is_refd)
                          cpu_tlb_flushD_SE(va);
          }
  
          if ((pmap != pmap_kernel()) && (pmap == &curproc->p_vmspace->vm_pmap))
                  cpu_icache_sync_range(va, PAGE_SIZE);
          /*
           * If both the l2b_occupancy and the reservation are fully
           * populated, then attempt promotion.
           */
          if ((l2b->l2b_occupancy == L2_PTE_NUM_TOTAL) &&
              sp_enabled && (m->flags & PG_FICTITIOUS) == 0 &&
              vm_reserv_level_iffullpop(m) == 0)
                  pmap_promote_section(pmap, va);
  }
  
  /*
   * Maps a sequence of resident pages belonging to the same object.
   * The sequence begins with the given page m_start.  This page is
   * mapped at the given virtual address start.  Each subsequent page is
   * mapped at a virtual address that is offset from start by the same
   * amount as the page is offset from m_start within the object.  The
   * last page in the sequence is the page with the largest offset from
   * m_start that can be mapped at a virtual address less than the given
   * virtual address end.  Not every virtual page between start and end
   * is mapped; only those for which a resident page exists with the
   * corresponding offset from m_start are mapped.
   */
  void
  pmap_enter_object(pmap_t pmap, vm_offset_t start, vm_offset_t end,
      vm_page_t m_start, vm_prot_t prot)
  {
          vm_offset_t va;
          vm_page_t m;
          vm_pindex_t diff, psize;
          vm_prot_t access;
  
          VM_OBJECT_ASSERT_LOCKED(m_start->object);
  
          psize = atop(end - start);
          m = m_start;
          access = prot = prot & (VM_PROT_READ | VM_PROT_EXECUTE);
          rw_wlock(&pvh_global_lock);
          PMAP_LOCK(pmap);
          while (m != NULL && (diff = m->pindex - m_start->pindex) < psize) {
                  va = start + ptoa(diff);
                  if ((va & L1_S_OFFSET) == 0 && L2_NEXT_BUCKET(va) <= end &&
                      (VM_PAGE_TO_PHYS(m) & L1_S_OFFSET) == 0 &&
                      sp_enabled && vm_reserv_level_iffullpop(m) == 0 &&
                      pmap_enter_section(pmap, va, m, prot))
                          m = &m[L1_S_SIZE / PAGE_SIZE - 1];
                  else
                          pmap_enter_locked(pmap, va, access, m, prot,
                              FALSE, M_NOWAIT);
                  m = TAILQ_NEXT(m, listq);
          }
          PMAP_UNLOCK(pmap);
          rw_wunlock(&pvh_global_lock);
  }
  
  /*
   * this code makes some *MAJOR* assumptions:
   * 1. Current pmap & pmap exists.
   * 2. Not wired.
   * 3. Read access.
   * 4. No page table pages.
   * but is *MUCH* faster than pmap_enter...
   */
  
  void
  pmap_enter_quick(pmap_t pmap, vm_offset_t va, vm_page_t m, vm_prot_t prot)
  {
          vm_prot_t access;
  
          access = prot = prot & (VM_PROT_READ | VM_PROT_EXECUTE);
          rw_wlock(&pvh_global_lock);
          PMAP_LOCK(pmap);
          pmap_enter_locked(pmap, va, access, m, prot, FALSE, M_NOWAIT);
          PMAP_UNLOCK(pmap);
          rw_wunlock(&pvh_global_lock);
  }
  
  /*
   *      Routine:        pmap_change_wiring
   *      Function:       Change the wiring attribute for a map/virtual-address
   *                      pair.
   *      In/out conditions:
   *                      The mapping must already exist in the pmap.
   */
  void
  pmap_change_wiring(pmap_t pmap, vm_offset_t va, boolean_t wired)
  {
          struct l2_bucket *l2b;
          struct md_page *pvh;
          struct pv_entry *pve;
          pd_entry_t *pl1pd, l1pd;
          pt_entry_t *ptep, pte;
          vm_page_t m;
  
          rw_wlock(&pvh_global_lock);
          PMAP_LOCK(pmap);
          pl1pd = &pmap->pm_l1->l1_kva[L1_IDX(va)];
          l1pd = *pl1pd;
          if ((l1pd & L1_TYPE_MASK) == L1_S_PROTO) {
                  m = PHYS_TO_VM_PAGE(l1pd & L1_S_FRAME);
                  KASSERT((m != NULL) && ((m->oflags & VPO_UNMANAGED) == 0),
                      ("pmap_change_wiring: unmanaged superpage should not "
                       "be changed"));
                  KASSERT(pmap != pmap_kernel(),
                      ("pmap_change_wiring: managed kernel superpage "
                       "should not exist"));
                  pvh = pa_to_pvh(l1pd & L1_S_FRAME);
                  pve = pmap_find_pv(pvh, pmap, trunc_1mpage(va));
                  if (!wired != ((pve->pv_flags & PVF_WIRED) == 0)) {
                          if (!pmap_demote_section(pmap, va))
                                  panic("pmap_change_wiring: demotion failed");
                  } else
                          goto out;
          }
          l2b = pmap_get_l2_bucket(pmap, va);
          KASSERT(l2b, ("No l2b bucket in pmap_change_wiring"));
          ptep = &l2b->l2b_kva[l2pte_index(va)];
          pte = *ptep;
          m = PHYS_TO_VM_PAGE(l2pte_pa(pte));
          if (m != NULL)
                  pmap_modify_pv(m, pmap, va, PVF_WIRED,
                      wired == TRUE ? PVF_WIRED : 0);
  out:
          rw_wunlock(&pvh_global_lock);
          PMAP_UNLOCK(pmap);
  }
  
  
  /*
   *      Copy the range specified by src_addr/len
   *      from the source map to the range dst_addr/len
   *      in the destination map.
   *
   *      This routine is only advisory and need not do anything.
   */
  void
  pmap_copy(pmap_t dst_pmap, pmap_t src_pmap, vm_offset_t dst_addr,
      vm_size_t len, vm_offset_t src_addr)
  {
  }
  
  
  /*
   *      Routine:        pmap_extract
   *      Function:
   *              Extract the physical page address associated
   *              with the given map/virtual_address pair.
   */
  vm_paddr_t
  pmap_extract(pmap_t pmap, vm_offset_t va)
  {
          vm_paddr_t pa;
  
          PMAP_LOCK(pmap);
          pa = pmap_extract_locked(pmap, va);
          PMAP_UNLOCK(pmap);
          return (pa);
  }
  
  static vm_paddr_t
  pmap_extract_locked(pmap_t pmap, vm_offset_t va)
  {
          struct l2_dtable *l2;
          pd_entry_t l1pd;
          pt_entry_t *ptep, pte;
          vm_paddr_t pa;
          u_int l1idx;
  
          if (pmap != kernel_pmap)
                  PMAP_ASSERT_LOCKED(pmap);
          l1idx = L1_IDX(va);
          l1pd = pmap->pm_l1->l1_kva[l1idx];
          if (l1pte_section_p(l1pd)) {
                  /*
                   * These should only happen for the kernel pmap.
                   */
                  KASSERT(pmap == kernel_pmap, ("unexpected section"));
                  /* XXX: what to do about the bits > 32 ? */
                  if (l1pd & L1_S_SUPERSEC)
                          pa = (l1pd & L1_SUP_FRAME) | (va & L1_SUP_OFFSET);
                  else
                          pa = (l1pd & L1_S_FRAME) | (va & L1_S_OFFSET);
          } else {
                  /*
                   * Note that we can't rely on the validity of the L1
                   * descriptor as an indication that a mapping exists.
                   * We have to look it up in the L2 dtable.
                   */
                  l2 = pmap->pm_l2[L2_IDX(l1idx)];
                  if (l2 == NULL ||
                      (ptep = l2->l2_bucket[L2_BUCKET(l1idx)].l2b_kva) == NULL)
                          return (0);
                  pte = ptep[l2pte_index(va)];
                  if (pte == 0)
                          return (0);
                  switch (pte & L2_TYPE_MASK) {
                  case L2_TYPE_L:
                          pa = (pte & L2_L_FRAME) | (va & L2_L_OFFSET);
                          break;
                  default:
                          pa = (pte & L2_S_FRAME) | (va & L2_S_OFFSET);
                          break;
                  }
          }
          return (pa);
  }
  
  /*
   * Atomically extract and hold the physical page with the given
   * pmap and virtual address pair if that mapping permits the given
   * protection.
   *
   */
  vm_page_t
  pmap_extract_and_hold(pmap_t pmap, vm_offset_t va, vm_prot_t prot)
  {
          struct l2_dtable *l2;
          pd_entry_t l1pd;
          pt_entry_t *ptep, pte;
          vm_paddr_t pa, paddr;
          vm_page_t m = NULL;
          u_int l1idx;
          l1idx = L1_IDX(va);
          paddr = 0;
  
          PMAP_LOCK(pmap);
  retry:
          l1pd = pmap->pm_l1->l1_kva[l1idx];
          if (l1pte_section_p(l1pd)) {
                  /* XXX: what to do about the bits > 32 ? */
                  if (l1pd & L1_S_SUPERSEC)
                          pa = (l1pd & L1_SUP_FRAME) | (va & L1_SUP_OFFSET);
                  else
                          pa = (l1pd & L1_S_FRAME) | (va & L1_S_OFFSET);
                  if (vm_page_pa_tryrelock(pmap, pa & PG_FRAME, &paddr))
                          goto retry;
                  if (L1_S_WRITABLE(l1pd) || (prot & VM_PROT_WRITE) == 0) {
                          m = PHYS_TO_VM_PAGE(pa);
                          vm_page_hold(m);
                  }
          } else {
                  /*
                   * Note that we can't rely on the validity of the L1
                   * descriptor as an indication that a mapping exists.
                   * We have to look it up in the L2 dtable.
                   */
                  l2 = pmap->pm_l2[L2_IDX(l1idx)];
  
                  if (l2 == NULL ||
                      (ptep = l2->l2_bucket[L2_BUCKET(l1idx)].l2b_kva) == NULL) {
                          PMAP_UNLOCK(pmap);
                          return (NULL);
                  }
  
                  ptep = &ptep[l2pte_index(va)];
                  pte = *ptep;
  
                  if (pte == 0) {
                          PMAP_UNLOCK(pmap);
                          return (NULL);
                  } else if ((prot & VM_PROT_WRITE) && (pte & L2_APX)) {
                          PMAP_UNLOCK(pmap);
                          return (NULL);
                  } else {
                          switch (pte & L2_TYPE_MASK) {
                          case L2_TYPE_L:
                                  panic("extract and hold section mapping");
                                  break;
                          default:
                                  pa = (pte & L2_S_FRAME) | (va & L2_S_OFFSET);
                                  break;
                          }
                          if (vm_page_pa_tryrelock(pmap, pa & PG_FRAME, &paddr))
                                  goto retry;
                          m = PHYS_TO_VM_PAGE(pa);
                          vm_page_hold(m);
                  }
  
          }
  
          PMAP_UNLOCK(pmap);
          PA_UNLOCK_COND(paddr);
          return (m);
  }
  
  /*
   * Initialize a preallocated and zeroed pmap structure,
   * such as one in a vmspace structure.
   */
  
  int
  pmap_pinit(pmap_t pmap)
  {
          PDEBUG(1, printf("pmap_pinit: pmap = %08x\n", (uint32_t) pmap));
  
          pmap_alloc_l1(pmap);
          bzero(pmap->pm_l2, sizeof(pmap->pm_l2));
  
          CPU_ZERO(&pmap->pm_active);
  
          TAILQ_INIT(&pmap->pm_pvchunk);
          bzero(&pmap->pm_stats, sizeof pmap->pm_stats);
          pmap->pm_stats.resident_count = 1;
          if (vector_page < KERNBASE) {
                  pmap_enter(pmap, vector_page,
                      VM_PROT_READ, PHYS_TO_VM_PAGE(systempage.pv_pa),
                      VM_PROT_READ, 1);
          }
          return (1);
  }
  
  
  /***************************************************
   * Superpage management routines.
   ***************************************************/
  
  static PMAP_INLINE struct pv_entry *
  pmap_pvh_remove(struct md_page *pvh, pmap_t pmap, vm_offset_t va)
  {
          pv_entry_t pv;
  
          rw_assert(&pvh_global_lock, RA_WLOCKED);
  
          pv = pmap_find_pv(pvh, pmap, va);
          if (pv != NULL)
                  TAILQ_REMOVE(&pvh->pv_list, pv, pv_list);
  
          return (pv);
  }
  
  static void
  pmap_pvh_free(struct md_page *pvh, pmap_t pmap, vm_offset_t va)
  {
          pv_entry_t pv;
  
          pv = pmap_pvh_remove(pvh, pmap, va);
          KASSERT(pv != NULL, ("pmap_pvh_free: pv not found"));
          pmap_free_pv_entry(pmap, pv);
  }
  
  static boolean_t
  pmap_pv_insert_section(pmap_t pmap, vm_offset_t va, vm_paddr_t pa)
  {
          struct md_page *pvh;
          pv_entry_t pv;
  
          rw_assert(&pvh_global_lock, RA_WLOCKED);
          if (pv_entry_count < pv_entry_high_water && 
              (pv = pmap_get_pv_entry(pmap, TRUE)) != NULL) {
                  pv->pv_va = va;
                  pvh = pa_to_pvh(pa);
                  TAILQ_INSERT_TAIL(&pvh->pv_list, pv, pv_list);
                  return (TRUE);
          } else
                  return (FALSE);
  }
  
  /*
   * Create the pv entries for each of the pages within a superpage.
   */
  static void
  pmap_pv_demote_section(pmap_t pmap, vm_offset_t va, vm_paddr_t pa)
  {
          struct md_page *pvh;
          pv_entry_t pve, pv;
          vm_offset_t va_last;
          vm_page_t m;
  
          rw_assert(&pvh_global_lock, RA_WLOCKED);
          KASSERT((pa & L1_S_OFFSET) == 0,
              ("pmap_pv_demote_section: pa is not 1mpage aligned"));
  
          /*
           * Transfer the 1mpage's pv entry for this mapping to the first
           * page's pv list.
           */
          pvh = pa_to_pvh(pa);
          va = trunc_1mpage(va);
          pv = pmap_pvh_remove(pvh, pmap, va);
          KASSERT(pv != NULL, ("pmap_pv_demote_section: pv not found"));
          m = PHYS_TO_VM_PAGE(pa);
          TAILQ_INSERT_HEAD(&m->md.pv_list, pv, pv_list);
          /* Instantiate the remaining pv entries. */
          va_last = L2_NEXT_BUCKET(va) - PAGE_SIZE;
          do {
                  m++;
                  KASSERT((m->oflags & VPO_UNMANAGED) == 0,
                      ("pmap_pv_demote_section: page %p is not managed", m));
                  va += PAGE_SIZE;
                  pve = pmap_get_pv_entry(pmap, FALSE);
                  pmap_enter_pv(m, pve, pmap, va, pv->pv_flags);
          } while (va < va_last);
  }
  
  static void
  pmap_pv_promote_section(pmap_t pmap, vm_offset_t va, vm_paddr_t pa)
  {
          struct md_page *pvh;
          pv_entry_t pv;
          vm_offset_t va_last;
          vm_page_t m;
  
          rw_assert(&pvh_global_lock, RA_WLOCKED);
          KASSERT((pa & L1_S_OFFSET) == 0,
              ("pmap_pv_promote_section: pa is not 1mpage aligned"));
  
          /*
           * Transfer the first page's pv entry for this mapping to the
           * 1mpage's pv list.  Aside from avoiding the cost of a call
           * to get_pv_entry(), a transfer avoids the possibility that
           * get_pv_entry() calls pmap_pv_reclaim() and that pmap_pv_reclaim()
           * removes one of the mappings that is being promoted.
           */
          m = PHYS_TO_VM_PAGE(pa);
          va = trunc_1mpage(va);
          pv = pmap_pvh_remove(&m->md, pmap, va);
          KASSERT(pv != NULL, ("pmap_pv_promote_section: pv not found"));
          pvh = pa_to_pvh(pa);
          TAILQ_INSERT_TAIL(&pvh->pv_list, pv, pv_list);
          /* Free the remaining pv entries in the newly mapped section pages */
          va_last = L2_NEXT_BUCKET(va) - PAGE_SIZE;
          do {
                  m++;
                  va += PAGE_SIZE;
                  /*
                   * Don't care the flags, first pv contains sufficient
                   * information for all of the pages so nothing is really lost.
                   */
                  pmap_pvh_free(&m->md, pmap, va);
          } while (va < va_last);
  }
  
  /*
   * Tries to create a 1MB page mapping.  Returns TRUE if successful and
   * FALSE otherwise.  Fails if (1) page is unmanageg, kernel pmap or vectors
   * page, (2) a mapping already exists at the specified virtual address, or
   * (3) a pv entry cannot be allocated without reclaiming another pv entry. 
   */
  static boolean_t
  pmap_enter_section(pmap_t pmap, vm_offset_t va, vm_page_t m, vm_prot_t prot)
  {
          pd_entry_t *pl1pd;
          vm_offset_t pa;
          struct l2_bucket *l2b;
  
          rw_assert(&pvh_global_lock, RA_WLOCKED);
          PMAP_ASSERT_LOCKED(pmap);
  
          /* Skip kernel, vectors page and unmanaged mappings */
          if ((pmap == pmap_kernel()) || (L1_IDX(va) == L1_IDX(vector_page)) ||
              ((m->oflags & VPO_UNMANAGED) != 0)) {
                  CTR2(KTR_PMAP, "pmap_enter_section: failure for va %#lx"
                      " in pmap %p", va, pmap);
                  return (FALSE);
          }
          /*
           * Check whether this is a valid section superpage entry or
           * there is a l2_bucket associated with that L1 page directory.
           */
          va = trunc_1mpage(va);
          pl1pd = &pmap->pm_l1->l1_kva[L1_IDX(va)];
          l2b = pmap_get_l2_bucket(pmap, va);
          if ((*pl1pd & L1_S_PROTO) || (l2b != NULL)) {
                  CTR2(KTR_PMAP, "pmap_enter_section: failure for va %#lx"
                      " in pmap %p", va, pmap);
                  return (FALSE);
          }
          pa = VM_PAGE_TO_PHYS(m); 
          /*
           * Abort this mapping if its PV entry could not be created.
           */
          if (!pmap_pv_insert_section(pmap, va, VM_PAGE_TO_PHYS(m))) {
                  CTR2(KTR_PMAP, "pmap_enter_section: failure for va %#lx"
                      " in pmap %p", va, pmap);
                  return (FALSE);
          }
          /*
           * Increment counters.
           */
          pmap->pm_stats.resident_count += L2_PTE_NUM_TOTAL;
          /*
           * Despite permissions, mark the superpage read-only.
           */
          prot &= ~VM_PROT_WRITE;
          /*
           * Map the superpage.
           */
          pmap_map_section(pmap, va, pa, prot, FALSE);
  
          pmap_section_mappings++;
          CTR2(KTR_PMAP, "pmap_enter_section: success for va %#lx"
              " in pmap %p", va, pmap);
          return (TRUE);
  }
  
  /*
   * pmap_remove_section: do the things to unmap a superpage in a process
   */
  static void
  pmap_remove_section(pmap_t pmap, vm_offset_t sva)
  {
          struct md_page *pvh;
          struct l2_bucket *l2b;
          pd_entry_t *pl1pd, l1pd;
          vm_offset_t eva, va;
          vm_page_t m;
  
          PMAP_ASSERT_LOCKED(pmap);
          if ((pmap == pmap_kernel()) || (L1_IDX(sva) == L1_IDX(vector_page)))
                  return;
  
          KASSERT((sva & L1_S_OFFSET) == 0,
              ("pmap_remove_section: sva is not 1mpage aligned"));
  
          pl1pd = &pmap->pm_l1->l1_kva[L1_IDX(sva)];
          l1pd = *pl1pd;
  
          m = PHYS_TO_VM_PAGE(l1pd & L1_S_FRAME);
          KASSERT((m != NULL && ((m->oflags & VPO_UNMANAGED) == 0)),
              ("pmap_remove_section: no corresponding vm_page or "
              "page unmanaged"));
  
          pmap->pm_stats.resident_count -= L2_PTE_NUM_TOTAL;
          pvh = pa_to_pvh(l1pd & L1_S_FRAME);
          pmap_pvh_free(pvh, pmap, sva);
          eva = L2_NEXT_BUCKET(sva);
          for (va = sva, m = PHYS_TO_VM_PAGE(l1pd & L1_S_FRAME);
              va < eva; va += PAGE_SIZE, m++) {
                  /*
                   * Mark base pages referenced but skip marking them dirty.
                   * If the superpage is writeable, hence all base pages were
                   * already marked as dirty in pmap_fault_fixup() before
                   * promotion. Reference bit however, might not have been set
                   * for each base page when the superpage was created at once,
                   * not as a result of promotion.
                   */
                  if (L1_S_REFERENCED(l1pd))
                          vm_page_aflag_set(m, PGA_REFERENCED);
                  if (TAILQ_EMPTY(&m->md.pv_list) &&
                      TAILQ_EMPTY(&pvh->pv_list))
                          vm_page_aflag_clear(m, PGA_WRITEABLE);
          }
          
          l2b = pmap_get_l2_bucket(pmap, sva);
          if (l2b != NULL) {
                  KASSERT(l2b->l2b_occupancy == L2_PTE_NUM_TOTAL,
                      ("pmap_remove_section: l2_bucket occupancy error"));
                  pmap_free_l2_bucket(pmap, l2b, L2_PTE_NUM_TOTAL);
                  /*
                   * Now invalidate L1 slot as it was not invalidated in
                   * pmap_free_l2_bucket() due to L1_TYPE mismatch.
                   */
                  *pl1pd = 0;
                  PTE_SYNC(pl1pd);
          }
  }
  
  /*
   * Tries to promote the 256, contiguous 4KB page mappings that are
   * within a single l2_bucket to a single 1MB section mapping.
   * For promotion to occur, two conditions must be met: (1) the 4KB page
   * mappings must map aligned, contiguous physical memory and (2) the 4KB page
   * mappings must have identical characteristics.
   */
  static void
  pmap_promote_section(pmap_t pmap, vm_offset_t va)
  {
          pt_entry_t *firstptep, firstpte, oldpte, pa, *pte;
          vm_page_t m, oldm;
          vm_offset_t first_va, old_va;
          struct l2_bucket *l2b = NULL;
          vm_prot_t prot;
          struct pv_entry *pve, *first_pve;
  
          PMAP_ASSERT_LOCKED(pmap);
  
          prot = VM_PROT_ALL;
          /*
           * Skip promoting kernel pages. This is justified by following:
           * 1. Kernel is already mapped using section mappings in each pmap
           * 2. Managed mappings within the kernel are not to be promoted anyway
           */
          if (pmap == pmap_kernel()) {
                  pmap_section_p_failures++;
                  CTR2(KTR_PMAP, "pmap_promote_section: failure for va %#x"
                      " in pmap %p", va, pmap);
                  return;
          }
          /* Do not attemp to promote vectors pages */
          if (L1_IDX(va) == L1_IDX(vector_page)) {
                  pmap_section_p_failures++;
                  CTR2(KTR_PMAP, "pmap_promote_section: failure for va %#x"
                      " in pmap %p", va, pmap);
                  return;
          }
          /*
           * Examine the first PTE in the specified l2_bucket. Abort if this PTE
           * is either invalid, unused, or does not map the first 4KB physical
           * page within 1MB page.
           */
          first_va = trunc_1mpage(va);
          l2b = pmap_get_l2_bucket(pmap, first_va);
          KASSERT(l2b != NULL, ("pmap_promote_section: trying to promote "
              "not existing l2 bucket"));
          firstptep = &l2b->l2b_kva[0];
  
          firstpte = *firstptep;
          if ((l2pte_pa(firstpte) & L1_S_OFFSET) != 0) {
                  pmap_section_p_failures++;
                  CTR2(KTR_PMAP, "pmap_promote_section: failure for va %#x"
                      " in pmap %p", va, pmap);
                  return;
          }
  
          if ((firstpte & (L2_S_PROTO | L2_S_REF)) != (L2_S_PROTO | L2_S_REF)) {
                  pmap_section_p_failures++;
                  CTR2(KTR_PMAP, "pmap_promote_section: failure for va %#x"
                      " in pmap %p", va, pmap);
                  return;
          }
          /*
           * ARM uses pv_entry to mark particular mapping WIRED so don't promote
           * unmanaged pages since it is impossible to determine, whether the
           * page is wired or not if there is no corresponding pv_entry.
           */
          m = PHYS_TO_VM_PAGE(l2pte_pa(firstpte));
          if (m && ((m->oflags & VPO_UNMANAGED) != 0)) {
                  pmap_section_p_failures++;
                  CTR2(KTR_PMAP, "pmap_promote_section: failure for va %#x"
                      " in pmap %p", va, pmap);
                  return;
          }
          first_pve = pmap_find_pv(&m->md, pmap, first_va);
          /*
           * PTE is modified only on write due to modified bit
           * emulation. If the entry is referenced and writable
           * then it is modified and we don't clear write enable.
           * Otherwise, writing is disabled in PTE anyway and
           * we just configure protections for the section mapping
           * that is going to be created.
           */
          if (!L2_S_WRITABLE(firstpte) && (first_pve->pv_flags & PVF_WRITE)) {
                  first_pve->pv_flags &= ~PVF_WRITE;
                  prot &= ~VM_PROT_WRITE;
          }
  
          if (!L2_S_EXECUTABLE(firstpte))
                  prot &= ~VM_PROT_EXECUTE;
  
          /* 
           * Examine each of the other PTEs in the specified l2_bucket. 
           * Abort if this PTE maps an unexpected 4KB physical page or
           * does not have identical characteristics to the first PTE.
           */
          pa = l2pte_pa(firstpte) + ((L2_PTE_NUM_TOTAL - 1) * PAGE_SIZE);
          old_va = L2_NEXT_BUCKET(first_va) - PAGE_SIZE;
  
          for (pte = (firstptep + L2_PTE_NUM_TOTAL - 1); pte > firstptep; pte--) {
                  oldpte = *pte;
                  if (l2pte_pa(oldpte) != pa) {
                          pmap_section_p_failures++;
                          CTR2(KTR_PMAP, "pmap_promote_section: failure for "
                              "va %#x in pmap %p", va, pmap);
                          return;
                  }
                  if ((oldpte & L2_S_PROMOTE) != (firstpte & L2_S_PROMOTE)) {
                          pmap_section_p_failures++;
                          CTR2(KTR_PMAP, "pmap_promote_section: failure for "
                              "va %#x in pmap %p", va, pmap);
                          return;
                  }
                  oldm = PHYS_TO_VM_PAGE(l2pte_pa(oldpte));
                  if (oldm && ((oldm->oflags & VPO_UNMANAGED) != 0)) {
                          pmap_section_p_failures++;
                          CTR2(KTR_PMAP, "pmap_promote_section: failure for "
                              "va %#x in pmap %p", va, pmap);
                          return;
                  }
  
                  pve = pmap_find_pv(&oldm->md, pmap, old_va);
                  if (pve == NULL) {
                          pmap_section_p_failures++;
                          CTR2(KTR_PMAP, "pmap_promote_section: failure for "
                              "va %#x old_va  %x - no pve", va, old_va);
                          return;
                  }
  
                  if (!L2_S_WRITABLE(oldpte) && (pve->pv_flags & PVF_WRITE))
                          pve->pv_flags &= ~PVF_WRITE;
  
                  old_va -= PAGE_SIZE;
                  pa -= PAGE_SIZE;
          }
          /*
           * Promote the pv entries.
           */
          pmap_pv_promote_section(pmap, first_va, l2pte_pa(firstpte));
          /*
           * Map the superpage.
           */
          pmap_map_section(pmap, first_va, l2pte_pa(firstpte), prot, TRUE);
          pmap_section_promotions++;
          CTR2(KTR_PMAP, "pmap_promote_section: success for va %#x"
              " in pmap %p", first_va, pmap);
  }
  
  /*
   * Fills a l2_bucket with mappings to consecutive physical pages.
   */
  static void
  pmap_fill_l2b(struct l2_bucket *l2b, pt_entry_t newpte)
  {
          pt_entry_t *ptep;
          int i;
  
          for (i = 0; i < L2_PTE_NUM_TOTAL; i++) {
                  ptep = &l2b->l2b_kva[i];
                  *ptep = newpte;
                  PTE_SYNC(ptep);
  
                  newpte += PAGE_SIZE;
          }
  
          l2b->l2b_occupancy = L2_PTE_NUM_TOTAL;
  }
  
  /*
   * Tries to demote a 1MB section mapping. If demotion fails, the
   * 1MB section mapping is invalidated.
   */
  static boolean_t
  pmap_demote_section(pmap_t pmap, vm_offset_t va)
  {
          struct l2_bucket *l2b;
          struct pv_entry *l1pdpve;
          struct md_page *pvh;
          pd_entry_t *pl1pd, l1pd;
          pt_entry_t *firstptep, newpte;
          vm_offset_t pa;
          vm_page_t m;
  
          PMAP_ASSERT_LOCKED(pmap);
          /*
           * According to assumptions described in pmap_promote_section,
           * kernel is and always should be mapped using 1MB section mappings.
           * What more, managed kernel pages were not to be promoted. 
           */
          KASSERT(pmap != pmap_kernel() && L1_IDX(va) != L1_IDX(vector_page),
              ("pmap_demote_section: forbidden section mapping"));
  
          va = trunc_1mpage(va);
          pl1pd = &pmap->pm_l1->l1_kva[L1_IDX(va)];
          l1pd = *pl1pd;
          KASSERT((l1pd & L1_TYPE_MASK) == L1_S_PROTO,
              ("pmap_demote_section: not section or invalid section"));
          
          pa = l1pd & L1_S_FRAME;
          m = PHYS_TO_VM_PAGE(pa);
          KASSERT((m != NULL && (m->oflags & VPO_UNMANAGED) == 0),
              ("pmap_demote_section: no vm_page for selected superpage or"
               "unmanaged"));
  
          pvh = pa_to_pvh(pa);
          l1pdpve = pmap_find_pv(pvh, pmap, va);
          KASSERT(l1pdpve != NULL, ("pmap_demote_section: no pv entry for "
              "managed page"));
  
          l2b = pmap_get_l2_bucket(pmap, va);
          if (l2b == NULL) {
                  KASSERT((l1pdpve->pv_flags & PVF_WIRED) == 0,
                      ("pmap_demote_section: No l2_bucket for wired mapping"));
                  /*
                   * Invalidate the 1MB section mapping and return
                   * "failure" if the mapping was never accessed or the
                   * allocation of the new l2_bucket fails.
                   */
                  if (!L1_S_REFERENCED(l1pd) ||
                      (l2b = pmap_alloc_l2_bucket(pmap, va)) == NULL) {
                          /* Unmap and invalidate superpage. */
                          pmap_remove_section(pmap, trunc_1mpage(va));
                          CTR2(KTR_PMAP, "pmap_demote_section: failure for "
                              "va %#x in pmap %p", va, pmap);
                          return (FALSE);
                  }
          }
  
          /*
           * Now we should have corresponding l2_bucket available.
           * Let's process it to recreate 256 PTEs for each base page
           * within superpage.
           */
          newpte = pa | L1_S_DEMOTE(l1pd);
          if (m->md.pv_memattr != VM_MEMATTR_UNCACHEABLE)
                  newpte |= pte_l2_s_cache_mode;
  
          /*
           * If the l2_bucket is new, initialize it.
           */
          if (l2b->l2b_occupancy == 0)
                  pmap_fill_l2b(l2b, newpte);
          else {
                  firstptep = &l2b->l2b_kva[0];
                  KASSERT(l2pte_pa(*firstptep) == (pa),
                      ("pmap_demote_section: firstpte and newpte map different "
                       "physical addresses"));
                  /*
                   * If the mapping has changed attributes, update the page table
                   * entries.
                   */ 
                  if ((*firstptep & L2_S_PROMOTE) != (L1_S_DEMOTE(l1pd)))
                          pmap_fill_l2b(l2b, newpte);
          }
          /* Demote PV entry */
          pmap_pv_demote_section(pmap, va, pa);
  
          /* Now fix-up L1 */
          l1pd = l2b->l2b_phys | L1_C_DOM(pmap->pm_domain) | L1_C_PROTO;
          *pl1pd = l1pd;
          PTE_SYNC(pl1pd);
  
          pmap_section_demotions++;
          CTR2(KTR_PMAP, "pmap_demote_section: success for va %#x"
              " in pmap %p", va, pmap);
          return (TRUE);
  }
  
  /***************************************************
   * page management routines.
   ***************************************************/
  
  /*
   * We are in a serious low memory condition.  Resort to
   * drastic measures to free some pages so we can allocate
   * another pv entry chunk.
   */
  static vm_page_t
  pmap_pv_reclaim(pmap_t locked_pmap)
  {
          struct pch newtail;
          struct pv_chunk *pc;
          struct l2_bucket *l2b = NULL;
          pmap_t pmap;
          pd_entry_t *pl1pd;
          pt_entry_t *ptep;
          pv_entry_t pv;
          vm_offset_t va;
          vm_page_t free, m, m_pc;
          uint32_t inuse;
          int bit, field, freed, idx;
  
          PMAP_ASSERT_LOCKED(locked_pmap);
          pmap = NULL;
          free = m_pc = NULL;
          TAILQ_INIT(&newtail);
          while ((pc = TAILQ_FIRST(&pv_chunks)) != NULL && (pv_vafree == 0 ||
              free == NULL)) {
                  TAILQ_REMOVE(&pv_chunks, pc, pc_lru);
                  if (pmap != pc->pc_pmap) {
                          if (pmap != NULL) {
                                  cpu_tlb_flushID();
                                  cpu_cpwait();
                                  if (pmap != locked_pmap)
                                          PMAP_UNLOCK(pmap);
                          }
                          pmap = pc->pc_pmap;
                          /* Avoid deadlock and lock recursion. */
                          if (pmap > locked_pmap)
                                  PMAP_LOCK(pmap);
                          else if (pmap != locked_pmap && !PMAP_TRYLOCK(pmap)) {
                                  pmap = NULL;
                                  TAILQ_INSERT_TAIL(&newtail, pc, pc_lru);
                                  continue;
                          }
                  }
  
                  /*
                   * Destroy every non-wired, 4 KB page mapping in the chunk.
                   */
                  freed = 0;
                  for (field = 0; field < _NPCM; field++) {
                          for (inuse = ~pc->pc_map[field] & pc_freemask[field];
                              inuse != 0; inuse &= ~(1UL << bit)) {
                                  bit = ffs(inuse) - 1;
                                  idx = field * sizeof(inuse) * NBBY + bit;
                                  pv = &pc->pc_pventry[idx];
                                  va = pv->pv_va;
  
                                  pl1pd = &pmap->pm_l1->l1_kva[L1_IDX(va)];
                                  if ((*pl1pd & L1_TYPE_MASK) == L1_S_PROTO)
                                          continue;
                                  if (pv->pv_flags & PVF_WIRED)
                                          continue;
  
                                  l2b = pmap_get_l2_bucket(pmap, va);
                                  KASSERT(l2b != NULL, ("No l2 bucket"));
                                  ptep = &l2b->l2b_kva[l2pte_index(va)];
                                  m = PHYS_TO_VM_PAGE(l2pte_pa(*ptep));
                                  KASSERT((vm_offset_t)m >= KERNBASE,
                                      ("Trying to access non-existent page "
                                       "va %x pte %x", va, *ptep));
                                  *ptep = 0;
                                  PTE_SYNC(ptep);
                                  TAILQ_REMOVE(&m->md.pv_list, pv, pv_list);
                                  if (TAILQ_EMPTY(&m->md.pv_list))
                                          vm_page_aflag_clear(m, PGA_WRITEABLE);
                                  pc->pc_map[field] |= 1UL << bit;
                                  freed++;
                          }
                  }
  
                  if (freed == 0) {
                          TAILQ_INSERT_TAIL(&newtail, pc, pc_lru);
                          continue;
                  }
                  /* Every freed mapping is for a 4 KB page. */
                  pmap->pm_stats.resident_count -= freed;
                  PV_STAT(pv_entry_frees += freed);
                  PV_STAT(pv_entry_spare += freed);
                  pv_entry_count -= freed;
                  TAILQ_REMOVE(&pmap->pm_pvchunk, pc, pc_list);
                  for (field = 0; field < _NPCM; field++)
                          if (pc->pc_map[field] != pc_freemask[field]) {
                                  TAILQ_INSERT_HEAD(&pmap->pm_pvchunk, pc,
                                      pc_list);
                                  TAILQ_INSERT_TAIL(&newtail, pc, pc_lru);
  
                                  /*
                                   * One freed pv entry in locked_pmap is
                                   * sufficient.
                                   */
                                  if (pmap == locked_pmap)
                                          goto out;
                                  break;
                          }
                  if (field == _NPCM) {
                          PV_STAT(pv_entry_spare -= _NPCPV);
                          PV_STAT(pc_chunk_count--);
                          PV_STAT(pc_chunk_frees++);
                          /* Entire chunk is free; return it. */
                          m_pc = PHYS_TO_VM_PAGE(pmap_kextract((vm_offset_t)pc));
                          pmap_qremove((vm_offset_t)pc, 1);
                          pmap_ptelist_free(&pv_vafree, (vm_offset_t)pc);
                          break;
                  }
          }
  out:
          TAILQ_CONCAT(&pv_chunks, &newtail, pc_lru);
          if (pmap != NULL) {
                  cpu_tlb_flushID();
                  cpu_cpwait();
                  if (pmap != locked_pmap)
                          PMAP_UNLOCK(pmap);
          }
          return (m_pc);
  }
  
  /*
   * free the pv_entry back to the free list
   */
  static void
  pmap_free_pv_entry(pmap_t pmap, pv_entry_t pv)
  {
          struct pv_chunk *pc;
          int bit, field, idx;
  
          rw_assert(&pvh_global_lock, RA_WLOCKED);
          PMAP_ASSERT_LOCKED(pmap);
          PV_STAT(pv_entry_frees++);
          PV_STAT(pv_entry_spare++);
          pv_entry_count--;
          pc = pv_to_chunk(pv);
          idx = pv - &pc->pc_pventry[0];
          field = idx / (sizeof(u_long) * NBBY);
          bit = idx % (sizeof(u_long) * NBBY);
          pc->pc_map[field] |= 1ul << bit;
          for (idx = 0; idx < _NPCM; idx++)
                  if (pc->pc_map[idx] != pc_freemask[idx]) {
                          /*
                           * 98% of the time, pc is already at the head of the
                           * list.  If it isn't already, move it to the head.
                           */
                          if (__predict_false(TAILQ_FIRST(&pmap->pm_pvchunk) !=
                              pc)) {
                                  TAILQ_REMOVE(&pmap->pm_pvchunk, pc, pc_list);
                                  TAILQ_INSERT_HEAD(&pmap->pm_pvchunk, pc,
                                      pc_list);
                          }
                          return;
                  }
          TAILQ_REMOVE(&pmap->pm_pvchunk, pc, pc_list);
          pmap_free_pv_chunk(pc);
  }
  
  static void
  pmap_free_pv_chunk(struct pv_chunk *pc)
  {
          vm_page_t m;
  
          TAILQ_REMOVE(&pv_chunks, pc, pc_lru);
          PV_STAT(pv_entry_spare -= _NPCPV);
          PV_STAT(pc_chunk_count--);
          PV_STAT(pc_chunk_frees++);
          /* entire chunk is free, return it */
          m = PHYS_TO_VM_PAGE(pmap_kextract((vm_offset_t)pc));
          pmap_qremove((vm_offset_t)pc, 1);
          vm_page_unwire(m, 0);
          vm_page_free(m);
          pmap_ptelist_free(&pv_vafree, (vm_offset_t)pc);
  
  }
  
  static pv_entry_t
  pmap_get_pv_entry(pmap_t pmap, boolean_t try)
  {
          static const struct timeval printinterval = { 60, 0 };
          static struct timeval lastprint;
          struct pv_chunk *pc;
          pv_entry_t pv;
          vm_page_t m;
          int bit, field, idx;
  
          rw_assert(&pvh_global_lock, RA_WLOCKED);
          PMAP_ASSERT_LOCKED(pmap);
          PV_STAT(pv_entry_allocs++);
          pv_entry_count++;
  
          if (pv_entry_count > pv_entry_high_water)
                  if (ratecheck(&lastprint, &printinterval))
                          printf("%s: Approaching the limit on PV entries.\n",
                              __func__);
  retry:
          pc = TAILQ_FIRST(&pmap->pm_pvchunk);
          if (pc != NULL) {
                  for (field = 0; field < _NPCM; field++) {
                          if (pc->pc_map[field]) {
                                  bit = ffs(pc->pc_map[field]) - 1;
                                  break;
                          }
                  }
                  if (field < _NPCM) {
                          idx = field * sizeof(pc->pc_map[field]) * NBBY + bit;
                          pv = &pc->pc_pventry[idx];
                          pc->pc_map[field] &= ~(1ul << bit);
                          /* If this was the last item, move it to tail */
                          for (field = 0; field < _NPCM; field++)
                                  if (pc->pc_map[field] != 0) {
                                          PV_STAT(pv_entry_spare--);
                                          return (pv);    /* not full, return */
                                  }
                          TAILQ_REMOVE(&pmap->pm_pvchunk, pc, pc_list);
                          TAILQ_INSERT_TAIL(&pmap->pm_pvchunk, pc, pc_list);
                          PV_STAT(pv_entry_spare--);
                          return (pv);
                  }
          }
          /*
           * Access to the ptelist "pv_vafree" is synchronized by the pvh
           * global lock.  If "pv_vafree" is currently non-empty, it will
           * remain non-empty until pmap_ptelist_alloc() completes.
           */
          if (pv_vafree == 0 || (m = vm_page_alloc(NULL, 0, VM_ALLOC_NORMAL |
              VM_ALLOC_NOOBJ | VM_ALLOC_WIRED)) == NULL) {
                  if (try) {
                          pv_entry_count--;
                          PV_STAT(pc_chunk_tryfail++);
                          return (NULL);
                  }
                  m = pmap_pv_reclaim(pmap);
                  if (m == NULL)
                          goto retry;
          }
          PV_STAT(pc_chunk_count++);
          PV_STAT(pc_chunk_allocs++);
          pc = (struct pv_chunk *)pmap_ptelist_alloc(&pv_vafree);
          pmap_qenter((vm_offset_t)pc, &m, 1);
          pc->pc_pmap = pmap;
          pc->pc_map[0] = pc_freemask[0] & ~1ul;  /* preallocated bit 0 */
          for (field = 1; field < _NPCM; field++)
                  pc->pc_map[field] = pc_freemask[field];
          TAILQ_INSERT_TAIL(&pv_chunks, pc, pc_lru);
          pv = &pc->pc_pventry[0];
          TAILQ_INSERT_HEAD(&pmap->pm_pvchunk, pc, pc_list);
          PV_STAT(pv_entry_spare += _NPCPV - 1);
          return (pv);
  }
  
  /*
   *      Remove the given range of addresses from the specified map.
   *
   *      It is assumed that the start and end are properly
   *      rounded to the page size.
   */
  #define PMAP_REMOVE_CLEAN_LIST_SIZE     3
  void
  pmap_remove(pmap_t pmap, vm_offset_t sva, vm_offset_t eva)
  {
          struct l2_bucket *l2b;
          vm_offset_t next_bucket;
          pd_entry_t *pl1pd, l1pd;
          pt_entry_t *ptep;
          u_int total;
          u_int mappings, is_exec, is_refd;
          int flushall = 0;
  
  
          /*
           * we lock in the pmap => pv_head direction
           */
  
          rw_wlock(&pvh_global_lock);
          PMAP_LOCK(pmap);
          total = 0;
          while (sva < eva) {
                  /*
                   * Check for large page.
                   */
                  pl1pd = &pmap->pm_l1->l1_kva[L1_IDX(sva)];
                  l1pd = *pl1pd;
                  if ((l1pd & L1_TYPE_MASK) == L1_S_PROTO) {
                          KASSERT((l1pd & L1_S_DOM_MASK) !=
                              L1_S_DOM(PMAP_DOMAIN_KERNEL), ("pmap_remove: "
                              "Trying to remove kernel section mapping"));
                          /*
                           * Are we removing the entire large page?  If not,
                           * demote the mapping and fall through.
                           */
                          if (sva + L1_S_SIZE == L2_NEXT_BUCKET(sva) &&
                              eva >= L2_NEXT_BUCKET(sva)) {
                                  pmap_remove_section(pmap, sva);
                                  sva = L2_NEXT_BUCKET(sva);
                                  continue;
                          } else if (!pmap_demote_section(pmap, sva)) {
                                  /* The large page mapping was destroyed. */
                                  sva = L2_NEXT_BUCKET(sva);
                                  continue;
                          }
                  }
                  /*
                   * Do one L2 bucket's worth at a time.
                   */
                  next_bucket = L2_NEXT_BUCKET(sva);
                  if (next_bucket > eva)
                          next_bucket = eva;
  
                  l2b = pmap_get_l2_bucket(pmap, sva);
                  if (l2b == NULL) {
                          sva = next_bucket;
                          continue;
                  }
  
                  ptep = &l2b->l2b_kva[l2pte_index(sva)];
                  mappings = 0;
  
                  while (sva < next_bucket) {
                          struct vm_page *m;
                          pt_entry_t pte;
                          vm_paddr_t pa;
  
                          pte = *ptep;
  
                          if (pte == 0) {
                                  /*
                                   * Nothing here, move along
                                   */
                                  sva += PAGE_SIZE;
                                  ptep++;
                                  continue;
                          }
  
                          pmap->pm_stats.resident_count--;
                          pa = l2pte_pa(pte);
                          is_exec = 0;
                          is_refd = 1;
  
                          /*
                           * Update flags. In a number of circumstances,
                           * we could cluster a lot of these and do a
                           * number of sequential pages in one go.
                           */
                          if ((m = PHYS_TO_VM_PAGE(pa)) != NULL) {
                                  struct pv_entry *pve;
  
                                  pve = pmap_remove_pv(m, pmap, sva);
                                  if (pve) {
                                          is_exec = PTE_BEEN_EXECD(pte);
                                          is_refd = PTE_BEEN_REFD(pte);
                                          pmap_free_pv_entry(pmap, pve);
                                  }
                          }
  
                          if (pmap_is_current(pmap)) {
                                  total++;
                                  if (total < PMAP_REMOVE_CLEAN_LIST_SIZE) {
                                          if (is_exec)
                                                  cpu_tlb_flushID_SE(sva);
                                          else if (is_refd)
                                                  cpu_tlb_flushD_SE(sva);
                                  } else if (total == PMAP_REMOVE_CLEAN_LIST_SIZE)
                                          flushall = 1;
                          }
                          *ptep = 0;
                          PTE_SYNC(ptep);
  
                          sva += PAGE_SIZE;
                          ptep++;
                          mappings++;
                  }
  
                  pmap_free_l2_bucket(pmap, l2b, mappings);
          }
  
          rw_wunlock(&pvh_global_lock);
          if (flushall)
                  cpu_tlb_flushID();
          PMAP_UNLOCK(pmap);
  }
  
  /*
   * pmap_zero_page()
   *
   * Zero a given physical page by mapping it at a page hook point.
   * In doing the zero page op, the page we zero is mapped cachable, as with
   * StrongARM accesses to non-cached pages are non-burst making writing
   * _any_ bulk data very slow.
   */
  static void
  pmap_zero_page_gen(vm_page_t m, int off, int size)
  {
  
          vm_paddr_t phys = VM_PAGE_TO_PHYS(m);
          if (!TAILQ_EMPTY(&m->md.pv_list))
                  panic("pmap_zero_page: page has mappings");
  
          mtx_lock(&cmtx);
          /*
           * Hook in the page, zero it, invalidate the TLB as needed.
           *
           * Note the temporary zero-page mapping must be a non-cached page in
           * order to work without corruption when write-allocate is enabled.
           */
          *cdst_pte = L2_S_PROTO | phys | pte_l2_s_cache_mode | L2_S_REF;
          pmap_set_prot(cdst_pte, VM_PROT_WRITE, 0);
          PTE_SYNC(cdst_pte);
          cpu_tlb_flushD_SE(cdstp);
          cpu_cpwait();
          if (off || size != PAGE_SIZE)
                  bzero((void *)(cdstp + off), size);
          else
                  bzero_page(cdstp);
  
          /*
           * Although aliasing is not possible if we use 
           * cdstp temporary mappings with memory that 
           * will be mapped later as non-cached or with write-through 
           * caches we might end up overwriting it when calling wbinv_all
           * So make sure caches are clean after copy operation
           */
          cpu_idcache_wbinv_range(cdstp, size);
          pmap_l2cache_wbinv_range(cdstp, phys, size);
  
          mtx_unlock(&cmtx);
  }
  
  /*
   *      pmap_zero_page zeros the specified hardware page by mapping
   *      the page into KVM and using bzero to clear its contents.
   */
  void
  pmap_zero_page(vm_page_t m)
  {
          pmap_zero_page_gen(m, 0, PAGE_SIZE);
  }
  
  
  /*
   *      pmap_zero_page_area zeros the specified hardware page by mapping
   *      the page into KVM and using bzero to clear its contents.
   *
   *      off and size may not cover an area beyond a single hardware page.
   */
  void
  pmap_zero_page_area(vm_page_t m, int off, int size)
  {
  
          pmap_zero_page_gen(m, off, size);
  }
  
  
  /*
   *      pmap_zero_page_idle zeros the specified hardware page by mapping
   *      the page into KVM and using bzero to clear its contents.  This
   *      is intended to be called from the vm_pagezero process only and
   *      outside of Giant.
   */
  void
  pmap_zero_page_idle(vm_page_t m)
  {
  
          pmap_zero_page(m);
  }
  
  /*
   *      pmap_copy_page copies the specified (machine independent)
   *      page by mapping the page into virtual memory and using
   *      bcopy to copy the page, one machine dependent page at a
   *      time.
   */
  
  /*
   * pmap_copy_page()
   *
   * Copy one physical page into another, by mapping the pages into
   * hook points. The same comment regarding cachability as in
   * pmap_zero_page also applies here.
   */
  void
  pmap_copy_page_generic(vm_paddr_t src, vm_paddr_t dst)
  {
          /*
           * Hold the source page's lock for the duration of the copy
           * so that no other mappings can be created while we have a
           * potentially aliased mapping.
           * Map the pages into the page hook points, copy them, and purge
           * the cache for the appropriate page. Invalidate the TLB
           * as required.
           */
          mtx_lock(&cmtx);
  
          /* For ARMv6 using System bit is deprecated and mapping with AP
           * bits set to 0x0 makes page not accessible. csrc_pte is mapped
           * read/write until proper mapping defines are created for ARMv6.
           */
          *csrc_pte = L2_S_PROTO | src | pte_l2_s_cache_mode | L2_S_REF;
          pmap_set_prot(csrc_pte, VM_PROT_READ, 0);
          PTE_SYNC(csrc_pte);
  
          *cdst_pte = L2_S_PROTO | dst | pte_l2_s_cache_mode | L2_S_REF;
          pmap_set_prot(cdst_pte, VM_PROT_READ | VM_PROT_WRITE, 0);
          PTE_SYNC(cdst_pte);
  
          cpu_tlb_flushD_SE(csrcp);
          cpu_tlb_flushD_SE(cdstp);
          cpu_cpwait();
  
          /*
           * Although aliasing is not possible if we use 
           * cdstp temporary mappings with memory that 
           * will be mapped later as non-cached or with write-through 
           * caches we might end up overwriting it when calling wbinv_all
           * So make sure caches are clean after copy operation
           */
          bcopy_page(csrcp, cdstp);
  
          cpu_idcache_wbinv_range(cdstp, PAGE_SIZE);
          pmap_l2cache_wbinv_range(cdstp, dst, PAGE_SIZE);
  
          mtx_unlock(&cmtx);
  }
  
  int unmapped_buf_allowed = 1;
  
  void
  pmap_copy_pages(vm_page_t ma[], vm_offset_t a_offset, vm_page_t mb[],
      vm_offset_t b_offset, int xfersize)
  {
          vm_page_t a_pg, b_pg;
          vm_offset_t a_pg_offset, b_pg_offset;
          int cnt;
  
          mtx_lock(&cmtx);
          while (xfersize > 0) {
                  a_pg = ma[a_offset >> PAGE_SHIFT];
                  a_pg_offset = a_offset & PAGE_MASK;
                  cnt = min(xfersize, PAGE_SIZE - a_pg_offset);
                  b_pg = mb[b_offset >> PAGE_SHIFT];
                  b_pg_offset = b_offset & PAGE_MASK;
                  cnt = min(cnt, PAGE_SIZE - b_pg_offset);
                  *csrc_pte = L2_S_PROTO | VM_PAGE_TO_PHYS(a_pg) |
                      pte_l2_s_cache_mode | L2_S_REF;
                  pmap_set_prot(csrc_pte, VM_PROT_READ, 0);
                  PTE_SYNC(csrc_pte);
                  *cdst_pte = L2_S_PROTO | VM_PAGE_TO_PHYS(b_pg) |
                      pte_l2_s_cache_mode | L2_S_REF;
                  pmap_set_prot(cdst_pte, VM_PROT_READ | VM_PROT_WRITE, 0);
                  PTE_SYNC(cdst_pte);
                  cpu_tlb_flushD_SE(csrcp);
                  cpu_tlb_flushD_SE(cdstp);
                  cpu_cpwait();
                  bcopy((char *)csrcp + a_pg_offset, (char *)cdstp + b_pg_offset,
                      cnt);
                  cpu_idcache_wbinv_range(cdstp + b_pg_offset, cnt);
                  pmap_l2cache_wbinv_range(cdstp + b_pg_offset,
                      VM_PAGE_TO_PHYS(b_pg) + b_pg_offset, cnt);
                  xfersize -= cnt;
                  a_offset += cnt;
                  b_offset += cnt;
          }
          mtx_unlock(&cmtx);
  }
  
  void
  pmap_copy_page(vm_page_t src, vm_page_t dst)
  {
  
          if (_arm_memcpy && PAGE_SIZE >= _min_memcpy_size &&
              _arm_memcpy((void *)VM_PAGE_TO_PHYS(dst),
              (void *)VM_PAGE_TO_PHYS(src), PAGE_SIZE, IS_PHYSICAL) == 0)
                  return;
  
          pmap_copy_page_generic(VM_PAGE_TO_PHYS(src), VM_PAGE_TO_PHYS(dst));
  }
  
  /*
   * this routine returns true if a physical page resides
   * in the given pmap.
   */
  boolean_t
  pmap_page_exists_quick(pmap_t pmap, vm_page_t m)
  {
          struct md_page *pvh;
          pv_entry_t pv;
          int loops = 0;
          boolean_t rv;
  
          KASSERT((m->oflags & VPO_UNMANAGED) == 0,
              ("pmap_page_exists_quick: page %p is not managed", m));
          rv = FALSE;
          rw_wlock(&pvh_global_lock);
          TAILQ_FOREACH(pv, &m->md.pv_list, pv_list) {
                  if (PV_PMAP(pv) == pmap) {
                          rv = TRUE;
                          break;
                  }
                  loops++;
                  if (loops >= 16)
                          break;
          }
          if (!rv && loops < 16 && (m->flags & PG_FICTITIOUS) == 0) {
                  pvh = pa_to_pvh(VM_PAGE_TO_PHYS(m));
                  TAILQ_FOREACH(pv, &pvh->pv_list, pv_list) {
                          if (PV_PMAP(pv) == pmap) {
                                  rv = TRUE;
                                  break;
                          }
                          loops++;
                          if (loops >= 16)
                                  break;
                  }
          }
          rw_wunlock(&pvh_global_lock);
          return (rv);
  }
  
  /*
   *      pmap_page_wired_mappings:
   *
   *      Return the number of managed mappings to the given physical page
   *      that are wired.
   */
  int
  pmap_page_wired_mappings(vm_page_t m)
  {
          int count;
  
          count = 0;
          if ((m->oflags & VPO_UNMANAGED) != 0)
                  return (count);
          rw_wlock(&pvh_global_lock);
          count = pmap_pvh_wired_mappings(&m->md, count);
          if ((m->flags & PG_FICTITIOUS) == 0) {
              count = pmap_pvh_wired_mappings(pa_to_pvh(VM_PAGE_TO_PHYS(m)),
                  count);
          }
          rw_wunlock(&pvh_global_lock);
          return (count);
  }
  
  /*
   *      pmap_pvh_wired_mappings:
   *
   *      Return the updated number "count" of managed mappings that are wired.
   */
  static int
  pmap_pvh_wired_mappings(struct md_page *pvh, int count)
  {
          pv_entry_t pv;
  
          rw_assert(&pvh_global_lock, RA_WLOCKED);
          TAILQ_FOREACH(pv, &pvh->pv_list, pv_list) {
                  if ((pv->pv_flags & PVF_WIRED) != 0)
                          count++;
          }
          return (count);
  }
  
  /*
   * Returns TRUE if any of the given mappings were referenced and FALSE
   * otherwise.  Both page and section mappings are supported.
   */
  static boolean_t
  pmap_is_referenced_pvh(struct md_page *pvh)
  {
          struct l2_bucket *l2b;
          pv_entry_t pv;
          pd_entry_t *pl1pd;
          pt_entry_t *ptep;
          pmap_t pmap;
          boolean_t rv;
  
          rw_assert(&pvh_global_lock, RA_WLOCKED);
          rv = FALSE;
          TAILQ_FOREACH(pv, &pvh->pv_list, pv_list) {
                  pmap = PV_PMAP(pv);
                  PMAP_LOCK(pmap);
                  pl1pd = &pmap->pm_l1->l1_kva[L1_IDX(pv->pv_va)];
                  if ((*pl1pd & L1_TYPE_MASK) == L1_S_PROTO)
                          rv = L1_S_REFERENCED(*pl1pd);
                  else {
                          l2b = pmap_get_l2_bucket(pmap, pv->pv_va);
                          ptep = &l2b->l2b_kva[l2pte_index(pv->pv_va)];
                          rv = L2_S_REFERENCED(*ptep);
                  }
                  PMAP_UNLOCK(pmap);
                  if (rv)
                          break;
          }
          return (rv);
  }
  
  /*
   *      pmap_is_referenced:
   *
   *      Return whether or not the specified physical page was referenced
   *      in any physical maps.
   */
  boolean_t
  pmap_is_referenced(vm_page_t m)
  {
          boolean_t rv;
  
          KASSERT((m->oflags & VPO_UNMANAGED) == 0,
              ("pmap_is_referenced: page %p is not managed", m));
          rw_wlock(&pvh_global_lock);
          rv = pmap_is_referenced_pvh(&m->md) ||
              ((m->flags & PG_FICTITIOUS) == 0 &&
              pmap_is_referenced_pvh(pa_to_pvh(VM_PAGE_TO_PHYS(m))));
          rw_wunlock(&pvh_global_lock);
          return (rv);
  }
  
  /*
   *      pmap_ts_referenced:
   *
   *      Return the count of reference bits for a page, clearing all of them.
   */
  int
  pmap_ts_referenced(vm_page_t m)
  {
  
          KASSERT((m->oflags & VPO_UNMANAGED) == 0,
              ("pmap_ts_referenced: page %p is not managed", m));
          return (pmap_clearbit(m, PVF_REF));
  }
  
  /*
   * Returns TRUE if any of the given mappings were used to modify
   * physical memory. Otherwise, returns FALSE. Both page and 1MB section
   * mappings are supported.
   */
  static boolean_t
  pmap_is_modified_pvh(struct md_page *pvh)
  {
          pd_entry_t *pl1pd;
          struct l2_bucket *l2b;
          pv_entry_t pv;
          pt_entry_t *ptep;
          pmap_t pmap;
          boolean_t rv;
  
          rw_assert(&pvh_global_lock, RA_WLOCKED);
          rv = FALSE;
  
          TAILQ_FOREACH(pv, &pvh->pv_list, pv_list) {
                  pmap = PV_PMAP(pv);
                  PMAP_LOCK(pmap);
                  pl1pd = &pmap->pm_l1->l1_kva[L1_IDX(pv->pv_va)];
                  if ((*pl1pd & L1_TYPE_MASK) == L1_S_PROTO)
                          rv = L1_S_WRITABLE(*pl1pd);
                  else {
                          l2b = pmap_get_l2_bucket(pmap, pv->pv_va);
                          ptep = &l2b->l2b_kva[l2pte_index(pv->pv_va)];
                          rv = L2_S_WRITABLE(*ptep);
                  }
                  PMAP_UNLOCK(pmap);
                  if (rv)
                          break;
          }
  
          return (rv);
  }
  
  boolean_t
  pmap_is_modified(vm_page_t m)
  {
          boolean_t rv;
  
          KASSERT((m->oflags & VPO_UNMANAGED) == 0,
              ("pmap_is_modified: page %p is not managed", m));
          /*
           * If the page is not exclusive busied, then PGA_WRITEABLE cannot be
           * concurrently set while the object is locked.  Thus, if PGA_WRITEABLE
           * is clear, no PTEs can have APX cleared.
           */
          VM_OBJECT_ASSERT_WLOCKED(m->object);
          if (!vm_page_xbusied(m) && (m->aflags & PGA_WRITEABLE) == 0)
                  return (FALSE);
          rw_wlock(&pvh_global_lock);
          rv = pmap_is_modified_pvh(&m->md) ||
              ((m->flags & PG_FICTITIOUS) == 0 &&
              pmap_is_modified_pvh(pa_to_pvh(VM_PAGE_TO_PHYS(m))));
          rw_wunlock(&pvh_global_lock);
          return (rv);
  }
  
  /*
   *      Apply the given advice to the specified range of addresses within the
   *      given pmap.  Depending on the advice, clear the referenced and/or
   *      modified flags in each mapping.
   */
  void
  pmap_advise(pmap_t pmap, vm_offset_t sva, vm_offset_t eva, int advice)
  {
          struct l2_bucket *l2b;
          struct pv_entry *pve;
          pd_entry_t *pl1pd, l1pd;
          pt_entry_t *ptep, opte, pte;
          vm_offset_t next_bucket;
          vm_page_t m;
  
          if (advice != MADV_DONTNEED && advice != MADV_FREE)
                  return;
          rw_wlock(&pvh_global_lock);
          PMAP_LOCK(pmap);
          for (; sva < eva; sva = next_bucket) {
                  next_bucket = L2_NEXT_BUCKET(sva);
                  if (next_bucket < sva)
                          next_bucket = eva;
                  pl1pd = &pmap->pm_l1->l1_kva[L1_IDX(sva)];
                  l1pd = *pl1pd;
                  if ((l1pd & L1_TYPE_MASK) == L1_S_PROTO) {
                          if (pmap == pmap_kernel())
                                  continue;
                          if (!pmap_demote_section(pmap, sva)) {
                                  /*
                                   * The large page mapping was destroyed.
                                   */
                                  continue;
                          }
                          /*
                           * Unless the page mappings are wired, remove the
                           * mapping to a single page so that a subsequent
                           * access may repromote. Since the underlying
                           * l2_bucket is fully populated, this removal
                           * never frees an entire l2_bucket.
                           */
                          l2b = pmap_get_l2_bucket(pmap, sva);
                          KASSERT(l2b != NULL,
                              ("pmap_advise: no l2 bucket for "
                               "va 0x%#x, pmap 0x%p", sva, pmap));
                          ptep = &l2b->l2b_kva[l2pte_index(sva)];
                          opte = *ptep;
                          m = PHYS_TO_VM_PAGE(l2pte_pa(*ptep));
                          KASSERT(m != NULL,
                              ("pmap_advise: no vm_page for demoted superpage"));
                          pve = pmap_find_pv(&m->md, pmap, sva);
                          KASSERT(pve != NULL,
                              ("pmap_advise: no PV entry for managed mapping"));
                          if ((pve->pv_flags & PVF_WIRED) == 0) {
                                  pmap_free_l2_bucket(pmap, l2b, 1);
                                  pve = pmap_remove_pv(m, pmap, sva);
                                  pmap_free_pv_entry(pmap, pve);
                                  *ptep = 0;
                                  PTE_SYNC(ptep);
                                  if (pmap_is_current(pmap)) {
                                          if (PTE_BEEN_EXECD(opte))
                                                  cpu_tlb_flushID_SE(sva);
                                          else if (PTE_BEEN_REFD(opte))
                                                  cpu_tlb_flushD_SE(sva);
                                  }
                          }
                  }
                  if (next_bucket > eva)
                          next_bucket = eva;
                  l2b = pmap_get_l2_bucket(pmap, sva);
                  if (l2b == NULL)
                          continue;
                  for (ptep = &l2b->l2b_kva[l2pte_index(sva)];
                      sva != next_bucket; ptep++, sva += PAGE_SIZE) {
                          opte = pte = *ptep;
                          if ((opte & L2_S_PROTO) == 0)
                                  continue;
                          m = PHYS_TO_VM_PAGE(l2pte_pa(opte));
                          if (m == NULL || (m->oflags & VPO_UNMANAGED) != 0)
                                  continue;
                          else if (L2_S_WRITABLE(opte)) {
                                  if (advice == MADV_DONTNEED) {
                                          /*
                                           * Don't need to mark the page
                                           * dirty as it was already marked as
                                           * such in pmap_fault_fixup() or
                                           * pmap_enter_locked().
                                           * Just clear the state.
                                           */
                                  } else
                                          pte |= L2_APX;
  
                                  pte &= ~L2_S_REF;
                                  *ptep = pte;
                                  PTE_SYNC(ptep);
                          } else if (L2_S_REFERENCED(opte)) {
                                  pte &= ~L2_S_REF;
                                  *ptep = pte;
                                  PTE_SYNC(ptep);
                          } else
                                  continue;
                          if (pmap_is_current(pmap)) {
                                  if (PTE_BEEN_EXECD(opte))
                                          cpu_tlb_flushID_SE(sva);
                                  else if (PTE_BEEN_REFD(opte))
                                          cpu_tlb_flushD_SE(sva);
                          }
                  }
          }
          rw_wunlock(&pvh_global_lock);
          PMAP_UNLOCK(pmap);
  }
  
  /*
   *      Clear the modify bits on the specified physical page.
   */
  void
  pmap_clear_modify(vm_page_t m)
  {
  
          KASSERT((m->oflags & VPO_UNMANAGED) == 0,
              ("pmap_clear_modify: page %p is not managed", m));
          VM_OBJECT_ASSERT_WLOCKED(m->object);
          KASSERT(!vm_page_xbusied(m),
              ("pmap_clear_modify: page %p is exclusive busied", m));
  
          /*
           * If the page is not PGA_WRITEABLE, then no mappings can be modified.
           * If the object containing the page is locked and the page is not
           * exclusive busied, then PGA_WRITEABLE cannot be concurrently set.
           */
          if ((m->aflags & PGA_WRITEABLE) == 0)
                  return;
          if (pmap_is_modified(m))
                  pmap_clearbit(m, PVF_MOD);
  }
  
  
  /*
   * Clear the write and modified bits in each of the given page's mappings.
   */
  void
  pmap_remove_write(vm_page_t m)
  {
          KASSERT((m->oflags & VPO_UNMANAGED) == 0,
              ("pmap_remove_write: page %p is not managed", m));
  
          /*
           * If the page is not exclusive busied, then PGA_WRITEABLE cannot be
           * set by another thread while the object is locked.  Thus,
           * if PGA_WRITEABLE is clear, no page table entries need updating.
           */
          VM_OBJECT_ASSERT_WLOCKED(m->object);
          if (vm_page_xbusied(m) || (m->aflags & PGA_WRITEABLE) != 0)
                  pmap_clearbit(m, PVF_WRITE);
  }
  
  
  /*
   * perform the pmap work for mincore
   */
  int
  pmap_mincore(pmap_t pmap, vm_offset_t addr, vm_paddr_t *locked_pa)
  {
          struct l2_bucket *l2b;
          pd_entry_t *pl1pd, l1pd;
          pt_entry_t *ptep, pte;
          vm_paddr_t pa;
          vm_page_t m;
          int val;
          boolean_t managed;
  
          PMAP_LOCK(pmap);
  retry:
          pl1pd = &pmap->pm_l1->l1_kva[L1_IDX(addr)];
          l1pd = *pl1pd;
          if ((l1pd & L1_TYPE_MASK) == L1_S_PROTO) {
                  pa = (l1pd & L1_S_FRAME);
                  val = MINCORE_SUPER | MINCORE_INCORE;
                  if (L1_S_WRITABLE(l1pd))
                          val |= MINCORE_MODIFIED | MINCORE_MODIFIED_OTHER;
                  managed = FALSE;
                  m = PHYS_TO_VM_PAGE(pa);
                  if (m != NULL && (m->oflags & VPO_UNMANAGED) == 0)
                          managed = TRUE;
                  if (managed) {
                          if (L1_S_REFERENCED(l1pd))
                                  val |= MINCORE_REFERENCED |
                                      MINCORE_REFERENCED_OTHER;
                  }
          } else {
                  l2b = pmap_get_l2_bucket(pmap, addr);
                  if (l2b == NULL) {
                          val = 0;
                          goto out;
                  }
                  ptep = &l2b->l2b_kva[l2pte_index(addr)];
                  pte = *ptep;
                  if (!l2pte_valid(pte)) {
                          val = 0;
                          goto out;
                  }
                  val = MINCORE_INCORE;
                  if (L2_S_WRITABLE(pte))
                          val |= MINCORE_MODIFIED | MINCORE_MODIFIED_OTHER;
                  managed = FALSE;
                  pa = l2pte_pa(pte);
                  m = PHYS_TO_VM_PAGE(pa);
                  if (m != NULL && (m->oflags & VPO_UNMANAGED) == 0)
                          managed = TRUE;
                  if (managed) {
                          if (L2_S_REFERENCED(pte))
                                  val |= MINCORE_REFERENCED |
                                      MINCORE_REFERENCED_OTHER;
                  }
          }
          if ((val & (MINCORE_MODIFIED_OTHER | MINCORE_REFERENCED_OTHER)) !=
              (MINCORE_MODIFIED_OTHER | MINCORE_REFERENCED_OTHER) && managed) {
                  /* Ensure that "PHYS_TO_VM_PAGE(pa)->object" doesn't change. */
                  if (vm_page_pa_tryrelock(pmap, pa, locked_pa))
                          goto retry;
          } else
  out:
                  PA_UNLOCK_COND(*locked_pa);
          PMAP_UNLOCK(pmap);
          return (val);
  }
  
  void
  pmap_sync_icache(pmap_t pmap, vm_offset_t va, vm_size_t sz)
  {
  }
  
  /*
   *      Increase the starting virtual address of the given mapping if a
   *      different alignment might result in more superpage mappings.
   */
  void
  pmap_align_superpage(vm_object_t object, vm_ooffset_t offset,
      vm_offset_t *addr, vm_size_t size)
  {
  }
  
  
  /*
   * Map a set of physical memory pages into the kernel virtual
   * address space. Return a pointer to where it is mapped. This
   * routine is intended to be used for mapping device memory,
   * NOT real memory.
   */
  void *
  pmap_mapdev(vm_offset_t pa, vm_size_t size)
  {
          vm_offset_t va, tmpva, offset;
  
          offset = pa & PAGE_MASK;
          size = roundup(size, PAGE_SIZE);
  
          GIANT_REQUIRED;
  
          va = kva_alloc(size);
          if (!va)
                  panic("pmap_mapdev: Couldn't alloc kernel virtual memory");
          for (tmpva = va; size > 0;) {
                  pmap_kenter_internal(tmpva, pa, 0);
                  size -= PAGE_SIZE;
                  tmpva += PAGE_SIZE;
                  pa += PAGE_SIZE;
          }
  
          return ((void *)(va + offset));
  }
  
  /*
   * pmap_map_section:
   *
   *      Create a single section mapping.
   */
  void
  pmap_map_section(pmap_t pmap, vm_offset_t va, vm_offset_t pa, vm_prot_t prot,
      boolean_t ref)
  {
          pd_entry_t *pl1pd, l1pd;
          pd_entry_t fl;
  
          KASSERT(((va | pa) & L1_S_OFFSET) == 0,
              ("Not a valid section mapping"));
  
          fl = pte_l1_s_cache_mode;
  
          pl1pd = &pmap->pm_l1->l1_kva[L1_IDX(va)];
          l1pd = L1_S_PROTO | pa | L1_S_PROT(PTE_USER, prot) | fl |
              L1_S_DOM(pmap->pm_domain);
  
          /* Mark page referenced if this section is a result of a promotion. */
          if (ref == TRUE)
                  l1pd |= L1_S_REF;
  #ifdef SMP
          l1pd |= L1_SHARED;
  #endif
          *pl1pd = l1pd;
          PTE_SYNC(pl1pd);
  }
  
  /*
   * pmap_link_l2pt:
   *
   *      Link the L2 page table specified by l2pv.pv_pa into the L1
   *      page table at the slot for "va".
   */
  void
  pmap_link_l2pt(vm_offset_t l1pt, vm_offset_t va, struct pv_addr *l2pv)
  {
          pd_entry_t *pde = (pd_entry_t *) l1pt, proto;
          u_int slot = va >> L1_S_SHIFT;
  
          proto = L1_S_DOM(PMAP_DOMAIN_KERNEL) | L1_C_PROTO;
  
  #ifdef VERBOSE_INIT_ARM
          printf("pmap_link_l2pt: pa=0x%x va=0x%x\n", l2pv->pv_pa, l2pv->pv_va);
  #endif
  
          pde[slot + 0] = proto | (l2pv->pv_pa + 0x000);
          PTE_SYNC(&pde[slot]);
  
          SLIST_INSERT_HEAD(&kernel_pt_list, l2pv, pv_list);
  
  }
  
  /*
   * pmap_map_entry
   *
   *      Create a single page mapping.
   */
  void
  pmap_map_entry(vm_offset_t l1pt, vm_offset_t va, vm_offset_t pa, int prot,
      int cache)
  {
          pd_entry_t *pde = (pd_entry_t *) l1pt;
          pt_entry_t fl;
          pt_entry_t *ptep;
  
          KASSERT(((va | pa) & PAGE_MASK) == 0, ("ouin"));
  
          fl = l2s_mem_types[cache];
  
          if ((pde[va >> L1_S_SHIFT] & L1_TYPE_MASK) != L1_TYPE_C)
                  panic("pmap_map_entry: no L2 table for VA 0x%08x", va);
  
          ptep = (pt_entry_t *)kernel_pt_lookup(pde[L1_IDX(va)] & L1_C_ADDR_MASK);
  
          if (ptep == NULL)
                  panic("pmap_map_entry: can't find L2 table for VA 0x%08x", va);
  
          ptep[l2pte_index(va)] = L2_S_PROTO | pa | fl | L2_S_REF;
          pmap_set_prot(&ptep[l2pte_index(va)], prot, 0);
          PTE_SYNC(&ptep[l2pte_index(va)]);
  }
  
  /*
   * pmap_map_chunk:
   *
   *      Map a chunk of memory using the most efficient mappings
   *      possible (section. large page, small page) into the
   *      provided L1 and L2 tables at the specified virtual address.
   */
  vm_size_t
  pmap_map_chunk(vm_offset_t l1pt, vm_offset_t va, vm_offset_t pa,
      vm_size_t size, int prot, int type)
  {
          pd_entry_t *pde = (pd_entry_t *) l1pt;
          pt_entry_t *ptep, f1, f2s, f2l;
          vm_size_t resid;
          int i;
  
          resid = (size + (PAGE_SIZE - 1)) & ~(PAGE_SIZE - 1);
  
          if (l1pt == 0)
                  panic("pmap_map_chunk: no L1 table provided");
  
  #ifdef VERBOSE_INIT_ARM
          printf("pmap_map_chunk: pa=0x%x va=0x%x size=0x%x resid=0x%x "
              "prot=0x%x type=%d\n", pa, va, size, resid, prot, type);
  #endif
  
          f1 = l1_mem_types[type];
          f2l = l2l_mem_types[type];
          f2s = l2s_mem_types[type];
  
          size = resid;
  
          while (resid > 0) {
                  /* See if we can use a section mapping. */
                  if (L1_S_MAPPABLE_P(va, pa, resid)) {
  #ifdef VERBOSE_INIT_ARM
                          printf("S");
  #endif
                          pde[va >> L1_S_SHIFT] = L1_S_PROTO | pa |
                              L1_S_PROT(PTE_KERNEL, prot | VM_PROT_EXECUTE) |
                              f1 | L1_S_DOM(PMAP_DOMAIN_KERNEL) | L1_S_REF;
                          PTE_SYNC(&pde[va >> L1_S_SHIFT]);
                          va += L1_S_SIZE;
                          pa += L1_S_SIZE;
                          resid -= L1_S_SIZE;
                          continue;
                  }
  
                  /*
                   * Ok, we're going to use an L2 table.  Make sure
                   * one is actually in the corresponding L1 slot
                   * for the current VA.
                   */
                  if ((pde[va >> L1_S_SHIFT] & L1_TYPE_MASK) != L1_TYPE_C)
                          panic("pmap_map_chunk: no L2 table for VA 0x%08x", va);
  
                  ptep = (pt_entry_t *) kernel_pt_lookup(
                      pde[L1_IDX(va)] & L1_C_ADDR_MASK);
                  if (ptep == NULL)
                          panic("pmap_map_chunk: can't find L2 table for VA"
                              "0x%08x", va);
                  /* See if we can use a L2 large page mapping. */
                  if (L2_L_MAPPABLE_P(va, pa, resid)) {
  #ifdef VERBOSE_INIT_ARM
                          printf("L");
  #endif
                          for (i = 0; i < 16; i++) {
                                  ptep[l2pte_index(va) + i] =
                                      L2_L_PROTO | pa |
                                      L2_L_PROT(PTE_KERNEL, prot) | f2l;
                                  PTE_SYNC(&ptep[l2pte_index(va) + i]);
                          }
                          va += L2_L_SIZE;
                          pa += L2_L_SIZE;
                          resid -= L2_L_SIZE;
                          continue;
                  }
  
                  /* Use a small page mapping. */
  #ifdef VERBOSE_INIT_ARM
                  printf("P");
  #endif
                  ptep[l2pte_index(va)] = L2_S_PROTO | pa | f2s | L2_S_REF;
                  pmap_set_prot(&ptep[l2pte_index(va)], prot, 0);
                  PTE_SYNC(&ptep[l2pte_index(va)]);
                  va += PAGE_SIZE;
                  pa += PAGE_SIZE;
                  resid -= PAGE_SIZE;
          }
  #ifdef VERBOSE_INIT_ARM
          printf("\n");
  #endif
          return (size);
  
  }
  
  /********************** Static device map routines ***************************/
  
  static const struct pmap_devmap *pmap_devmap_table;
  
  /*
   * Register the devmap table.  This is provided in case early console
   * initialization needs to register mappings created by bootstrap code
   * before pmap_devmap_bootstrap() is called.
   */
  void
  pmap_devmap_register(const struct pmap_devmap *table)
  {
  
          pmap_devmap_table = table;
  }
  
  /*
   * Map all of the static regions in the devmap table, and remember
   * the devmap table so other parts of the kernel can look up entries
   * later.
   */
  void
  pmap_devmap_bootstrap(vm_offset_t l1pt, const struct pmap_devmap *table)
  {
          int i;
  
          pmap_devmap_table = table;
  
          for (i = 0; pmap_devmap_table[i].pd_size != 0; i++) {
  #ifdef VERBOSE_INIT_ARM
                  printf("devmap: %08x -> %08x @ %08x\n",
                      pmap_devmap_table[i].pd_pa,
                      pmap_devmap_table[i].pd_pa +
                          pmap_devmap_table[i].pd_size - 1,
                      pmap_devmap_table[i].pd_va);
  #endif
                  pmap_map_chunk(l1pt, pmap_devmap_table[i].pd_va,
                      pmap_devmap_table[i].pd_pa,
                      pmap_devmap_table[i].pd_size,
                      pmap_devmap_table[i].pd_prot,
                      pmap_devmap_table[i].pd_cache);
          }
  }
  
  const struct pmap_devmap *
  pmap_devmap_find_pa(vm_paddr_t pa, vm_size_t size)
  {
          int i;
  
          if (pmap_devmap_table == NULL)
                  return (NULL);
  
          for (i = 0; pmap_devmap_table[i].pd_size != 0; i++) {
                  if (pa >= pmap_devmap_table[i].pd_pa &&
                      pa + size <= pmap_devmap_table[i].pd_pa +
                                   pmap_devmap_table[i].pd_size)
                          return (&pmap_devmap_table[i]);
          }
  
          return (NULL);
  }
  
  const struct pmap_devmap *
  pmap_devmap_find_va(vm_offset_t va, vm_size_t size)
  {
          int i;
  
          if (pmap_devmap_table == NULL)
                  return (NULL);
  
          for (i = 0; pmap_devmap_table[i].pd_size != 0; i++) {
                  if (va >= pmap_devmap_table[i].pd_va &&
                      va + size <= pmap_devmap_table[i].pd_va +
                                   pmap_devmap_table[i].pd_size)
                          return (&pmap_devmap_table[i]);
          }
  
          return (NULL);
  }
  
  int
  pmap_dmap_iscurrent(pmap_t pmap)
  {
          return(pmap_is_current(pmap));
  }
  
  void
  pmap_page_set_memattr(vm_page_t m, vm_memattr_t ma)
  {
          /* 
           * Remember the memattr in a field that gets used to set the appropriate
           * bits in the PTEs as mappings are established.
           */
          m->md.pv_memattr = ma;
  
          /*
           * It appears that this function can only be called before any mappings
           * for the page are established on ARM.  If this ever changes, this code
           * will need to walk the pv_list and make each of the existing mappings
           * uncacheable, being careful to sync caches and PTEs (and maybe
           * invalidate TLB?) for any current mapping it modifies.
           */
          if (TAILQ_FIRST(&m->md.pv_list) != NULL)
                  panic("Can't change memattr on page with existing mappings");
  }