FreeBSD/Linux Kernel Cross Reference
sys/powerpc/booke/pmap.c

     /*-
      * Copyright (C) 2007-2009 Semihalf, Rafal Jaworowski <raj@semihalf.com>
      * Copyright (C) 2006 Semihalf, Marian Balakowicz <m8@semihalf.com>
      * All rights reserved.
      *
      * 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 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 THIS
     * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
     *
     * Some hw specific parts of this pmap were derived or influenced
     * by NetBSD's ibm4xx pmap module. More generic code is shared with
     * a few other pmap modules from the FreeBSD tree.
     */
    
     /*
      * VM layout notes:
      *
      * Kernel and user threads run within one common virtual address space
      * defined by AS=0.
      *
      * Virtual address space layout:
      * -----------------------------
      * 0x0000_0000 - 0xafff_ffff   : user process
      * 0xb000_0000 - 0xbfff_ffff   : pmap_mapdev()-ed area (PCI/PCIE etc.)
      * 0xc000_0000 - 0xc0ff_ffff   : kernel reserved
      *   0xc000_0000 - data_end    : kernel code+data, env, metadata etc.
      * 0xc100_0000 - 0xfeef_ffff   : KVA
      *   0xc100_0000 - 0xc100_3fff : reserved for page zero/copy
      *   0xc100_4000 - 0xc200_3fff : reserved for ptbl bufs
      *   0xc200_4000 - 0xc200_8fff : guard page + kstack0
      *   0xc200_9000 - 0xfeef_ffff : actual free KVA space
      * 0xfef0_0000 - 0xffff_ffff   : I/O devices region
      */
    
    #include <sys/cdefs.h>
    __FBSDID("$FreeBSD: releng/11.0/sys/powerpc/booke/pmap.c 298642 2016-04-26 14:44:49Z pfg $");
    
    #include "opt_kstack_pages.h"
    
    #include <sys/param.h>
    #include <sys/conf.h>
    #include <sys/malloc.h>
    #include <sys/ktr.h>
    #include <sys/proc.h>
    #include <sys/user.h>
    #include <sys/queue.h>
    #include <sys/systm.h>
    #include <sys/kernel.h>
    #include <sys/kerneldump.h>
    #include <sys/linker.h>
    #include <sys/msgbuf.h>
    #include <sys/lock.h>
    #include <sys/mutex.h>
    #include <sys/rwlock.h>
    #include <sys/sched.h>
    #include <sys/smp.h>
    #include <sys/vmmeter.h>
    
    #include <vm/vm.h>
    #include <vm/vm_page.h>
    #include <vm/vm_kern.h>
    #include <vm/vm_pageout.h>
    #include <vm/vm_extern.h>
    #include <vm/vm_object.h>
    #include <vm/vm_param.h>
    #include <vm/vm_map.h>
    #include <vm/vm_pager.h>
    #include <vm/uma.h>
    
    #include <machine/cpu.h>
    #include <machine/pcb.h>
    #include <machine/platform.h>
    
    #include <machine/tlb.h>
    #include <machine/spr.h>
    #include <machine/md_var.h>
    #include <machine/mmuvar.h>
    #include <machine/pmap.h>
    #include <machine/pte.h>
    
    #include "mmu_if.h"
    
    #define SPARSE_MAPDEV
   #ifdef  DEBUG
   #define debugf(fmt, args...) printf(fmt, ##args)
   #else
   #define debugf(fmt, args...)
   #endif
   
   #define TODO                    panic("%s: not implemented", __func__);
   
   extern unsigned char _etext[];
   extern unsigned char _end[];
   
   extern uint32_t *bootinfo;
   
   vm_paddr_t kernload;
   vm_offset_t kernstart;
   vm_size_t kernsize;
   
   /* Message buffer and tables. */
   static vm_offset_t data_start;
   static vm_size_t data_end;
   
   /* Phys/avail memory regions. */
   static struct mem_region *availmem_regions;
   static int availmem_regions_sz;
   static struct mem_region *physmem_regions;
   static int physmem_regions_sz;
   
   /* Reserved KVA space and mutex for mmu_booke_zero_page. */
   static vm_offset_t zero_page_va;
   static struct mtx zero_page_mutex;
   
   static struct mtx tlbivax_mutex;
   
   /*
    * Reserved KVA space for mmu_booke_zero_page_idle. This is used
    * by idle thred only, no lock required.
    */
   static vm_offset_t zero_page_idle_va;
   
   /* Reserved KVA space and mutex for mmu_booke_copy_page. */
   static vm_offset_t copy_page_src_va;
   static vm_offset_t copy_page_dst_va;
   static struct mtx copy_page_mutex;
   
   /**************************************************************************/
   /* PMAP */
   /**************************************************************************/
   
   static int mmu_booke_enter_locked(mmu_t, pmap_t, vm_offset_t, vm_page_t,
       vm_prot_t, u_int flags, int8_t psind);
   
   unsigned int kptbl_min;         /* Index of the first kernel ptbl. */
   unsigned int kernel_ptbls;      /* Number of KVA ptbls. */
   
   /*
    * If user pmap is processed with mmu_booke_remove and the resident count
    * drops to 0, there are no more pages to remove, so we need not continue.
    */
   #define PMAP_REMOVE_DONE(pmap) \
           ((pmap) != kernel_pmap && (pmap)->pm_stats.resident_count == 0)
   
   extern int elf32_nxstack;
   
   /**************************************************************************/
   /* TLB and TID handling */
   /**************************************************************************/
   
   /* Translation ID busy table */
   static volatile pmap_t tidbusy[MAXCPU][TID_MAX + 1];
   
   /*
    * TLB0 capabilities (entry, way numbers etc.). These can vary between e500
    * core revisions and should be read from h/w registers during early config.
    */
   uint32_t tlb0_entries;
   uint32_t tlb0_ways;
   uint32_t tlb0_entries_per_way;
   uint32_t tlb1_entries;
   
   #define TLB0_ENTRIES            (tlb0_entries)
   #define TLB0_WAYS               (tlb0_ways)
   #define TLB0_ENTRIES_PER_WAY    (tlb0_entries_per_way)
   
   #define TLB1_ENTRIES (tlb1_entries)
   #define TLB1_MAXENTRIES 64
   
   static vm_offset_t tlb1_map_base = VM_MAXUSER_ADDRESS + PAGE_SIZE;
   
   static tlbtid_t tid_alloc(struct pmap *);
   static void tid_flush(tlbtid_t tid);
   
   static void tlb_print_entry(int, uint32_t, uint32_t, uint32_t, uint32_t);
   
   static void tlb1_read_entry(tlb_entry_t *, unsigned int);
   static void tlb1_write_entry(tlb_entry_t *, unsigned int);
   static int tlb1_iomapped(int, vm_paddr_t, vm_size_t, vm_offset_t *);
   static vm_size_t tlb1_mapin_region(vm_offset_t, vm_paddr_t, vm_size_t);
   
   static vm_size_t tsize2size(unsigned int);
   static unsigned int size2tsize(vm_size_t);
   static unsigned int ilog2(unsigned int);
   
   static void set_mas4_defaults(void);
   
   static inline void tlb0_flush_entry(vm_offset_t);
   static inline unsigned int tlb0_tableidx(vm_offset_t, unsigned int);
   
   /**************************************************************************/
   /* Page table management */
   /**************************************************************************/
   
   static struct rwlock_padalign pvh_global_lock;
   
   /* Data for the pv entry allocation mechanism */
   static uma_zone_t pvzone;
   static int pv_entry_count = 0, pv_entry_max = 0, pv_entry_high_water = 0;
   
   #define PV_ENTRY_ZONE_MIN       2048    /* min pv entries in uma zone */
   
   #ifndef PMAP_SHPGPERPROC
   #define PMAP_SHPGPERPROC        200
   #endif
   
   static void ptbl_init(void);
   static struct ptbl_buf *ptbl_buf_alloc(void);
   static void ptbl_buf_free(struct ptbl_buf *);
   static void ptbl_free_pmap_ptbl(pmap_t, pte_t *);
   
   static pte_t *ptbl_alloc(mmu_t, pmap_t, unsigned int, boolean_t);
   static void ptbl_free(mmu_t, pmap_t, unsigned int);
   static void ptbl_hold(mmu_t, pmap_t, unsigned int);
   static int ptbl_unhold(mmu_t, pmap_t, unsigned int);
   
   static vm_paddr_t pte_vatopa(mmu_t, pmap_t, vm_offset_t);
   static pte_t *pte_find(mmu_t, pmap_t, vm_offset_t);
   static int pte_enter(mmu_t, pmap_t, vm_page_t, vm_offset_t, uint32_t, boolean_t);
   static int pte_remove(mmu_t, pmap_t, vm_offset_t, uint8_t);
   static void kernel_pte_alloc(vm_offset_t data_end, vm_offset_t addr,
                                vm_offset_t pdir);
   
   static pv_entry_t pv_alloc(void);
   static void pv_free(pv_entry_t);
   static void pv_insert(pmap_t, vm_offset_t, vm_page_t);
   static void pv_remove(pmap_t, vm_offset_t, vm_page_t);
   
   static void booke_pmap_init_qpages(void);
   
   /* Number of kva ptbl buffers, each covering one ptbl (PTBL_PAGES). */
   #define PTBL_BUFS               (128 * 16)
   
   struct ptbl_buf {
           TAILQ_ENTRY(ptbl_buf) link;     /* list link */
           vm_offset_t kva;                /* va of mapping */
   };
   
   /* ptbl free list and a lock used for access synchronization. */
   static TAILQ_HEAD(, ptbl_buf) ptbl_buf_freelist;
   static struct mtx ptbl_buf_freelist_lock;
   
   /* Base address of kva space allocated fot ptbl bufs. */
   static vm_offset_t ptbl_buf_pool_vabase;
   
   /* Pointer to ptbl_buf structures. */
   static struct ptbl_buf *ptbl_bufs;
   
   #ifdef SMP
   extern tlb_entry_t __boot_tlb1[];
   void pmap_bootstrap_ap(volatile uint32_t *);
   #endif
   
   /*
    * Kernel MMU interface
    */
   static void             mmu_booke_clear_modify(mmu_t, vm_page_t);
   static void             mmu_booke_copy(mmu_t, pmap_t, pmap_t, vm_offset_t,
       vm_size_t, vm_offset_t);
   static void             mmu_booke_copy_page(mmu_t, vm_page_t, vm_page_t);
   static void             mmu_booke_copy_pages(mmu_t, vm_page_t *,
       vm_offset_t, vm_page_t *, vm_offset_t, int);
   static int              mmu_booke_enter(mmu_t, pmap_t, vm_offset_t, vm_page_t,
       vm_prot_t, u_int flags, int8_t psind);
   static void             mmu_booke_enter_object(mmu_t, pmap_t, vm_offset_t, vm_offset_t,
       vm_page_t, vm_prot_t);
   static void             mmu_booke_enter_quick(mmu_t, pmap_t, vm_offset_t, vm_page_t,
       vm_prot_t);
   static vm_paddr_t       mmu_booke_extract(mmu_t, pmap_t, vm_offset_t);
   static vm_page_t        mmu_booke_extract_and_hold(mmu_t, pmap_t, vm_offset_t,
       vm_prot_t);
   static void             mmu_booke_init(mmu_t);
   static boolean_t        mmu_booke_is_modified(mmu_t, vm_page_t);
   static boolean_t        mmu_booke_is_prefaultable(mmu_t, pmap_t, vm_offset_t);
   static boolean_t        mmu_booke_is_referenced(mmu_t, vm_page_t);
   static int              mmu_booke_ts_referenced(mmu_t, vm_page_t);
   static vm_offset_t      mmu_booke_map(mmu_t, vm_offset_t *, vm_paddr_t, vm_paddr_t,
       int);
   static int              mmu_booke_mincore(mmu_t, pmap_t, vm_offset_t,
       vm_paddr_t *);
   static void             mmu_booke_object_init_pt(mmu_t, pmap_t, vm_offset_t,
       vm_object_t, vm_pindex_t, vm_size_t);
   static boolean_t        mmu_booke_page_exists_quick(mmu_t, pmap_t, vm_page_t);
   static void             mmu_booke_page_init(mmu_t, vm_page_t);
   static int              mmu_booke_page_wired_mappings(mmu_t, vm_page_t);
   static void             mmu_booke_pinit(mmu_t, pmap_t);
   static void             mmu_booke_pinit0(mmu_t, pmap_t);
   static void             mmu_booke_protect(mmu_t, pmap_t, vm_offset_t, vm_offset_t,
       vm_prot_t);
   static void             mmu_booke_qenter(mmu_t, vm_offset_t, vm_page_t *, int);
   static void             mmu_booke_qremove(mmu_t, vm_offset_t, int);
   static void             mmu_booke_release(mmu_t, pmap_t);
   static void             mmu_booke_remove(mmu_t, pmap_t, vm_offset_t, vm_offset_t);
   static void             mmu_booke_remove_all(mmu_t, vm_page_t);
   static void             mmu_booke_remove_write(mmu_t, vm_page_t);
   static void             mmu_booke_unwire(mmu_t, pmap_t, vm_offset_t, vm_offset_t);
   static void             mmu_booke_zero_page(mmu_t, vm_page_t);
   static void             mmu_booke_zero_page_area(mmu_t, vm_page_t, int, int);
   static void             mmu_booke_zero_page_idle(mmu_t, vm_page_t);
   static void             mmu_booke_activate(mmu_t, struct thread *);
   static void             mmu_booke_deactivate(mmu_t, struct thread *);
   static void             mmu_booke_bootstrap(mmu_t, vm_offset_t, vm_offset_t);
   static void             *mmu_booke_mapdev(mmu_t, vm_paddr_t, vm_size_t);
   static void             *mmu_booke_mapdev_attr(mmu_t, vm_paddr_t, vm_size_t, vm_memattr_t);
   static void             mmu_booke_unmapdev(mmu_t, vm_offset_t, vm_size_t);
   static vm_paddr_t       mmu_booke_kextract(mmu_t, vm_offset_t);
   static void             mmu_booke_kenter(mmu_t, vm_offset_t, vm_paddr_t);
   static void             mmu_booke_kenter_attr(mmu_t, vm_offset_t, vm_paddr_t, vm_memattr_t);
   static void             mmu_booke_kremove(mmu_t, vm_offset_t);
   static boolean_t        mmu_booke_dev_direct_mapped(mmu_t, vm_paddr_t, vm_size_t);
   static void             mmu_booke_sync_icache(mmu_t, pmap_t, vm_offset_t,
       vm_size_t);
   static void             mmu_booke_dumpsys_map(mmu_t, vm_paddr_t pa, size_t,
       void **);
   static void             mmu_booke_dumpsys_unmap(mmu_t, vm_paddr_t pa, size_t,
       void *);
   static void             mmu_booke_scan_init(mmu_t);
   static vm_offset_t      mmu_booke_quick_enter_page(mmu_t mmu, vm_page_t m);
   static void             mmu_booke_quick_remove_page(mmu_t mmu, vm_offset_t addr);
   static int              mmu_booke_change_attr(mmu_t mmu, vm_offset_t addr,
       vm_size_t sz, vm_memattr_t mode);
   
   static mmu_method_t mmu_booke_methods[] = {
           /* pmap dispatcher interface */
           MMUMETHOD(mmu_clear_modify,     mmu_booke_clear_modify),
           MMUMETHOD(mmu_copy,             mmu_booke_copy),
           MMUMETHOD(mmu_copy_page,        mmu_booke_copy_page),
           MMUMETHOD(mmu_copy_pages,       mmu_booke_copy_pages),
           MMUMETHOD(mmu_enter,            mmu_booke_enter),
           MMUMETHOD(mmu_enter_object,     mmu_booke_enter_object),
           MMUMETHOD(mmu_enter_quick,      mmu_booke_enter_quick),
           MMUMETHOD(mmu_extract,          mmu_booke_extract),
           MMUMETHOD(mmu_extract_and_hold, mmu_booke_extract_and_hold),
           MMUMETHOD(mmu_init,             mmu_booke_init),
           MMUMETHOD(mmu_is_modified,      mmu_booke_is_modified),
           MMUMETHOD(mmu_is_prefaultable,  mmu_booke_is_prefaultable),
           MMUMETHOD(mmu_is_referenced,    mmu_booke_is_referenced),
           MMUMETHOD(mmu_ts_referenced,    mmu_booke_ts_referenced),
           MMUMETHOD(mmu_map,              mmu_booke_map),
           MMUMETHOD(mmu_mincore,          mmu_booke_mincore),
           MMUMETHOD(mmu_object_init_pt,   mmu_booke_object_init_pt),
           MMUMETHOD(mmu_page_exists_quick,mmu_booke_page_exists_quick),
           MMUMETHOD(mmu_page_init,        mmu_booke_page_init),
           MMUMETHOD(mmu_page_wired_mappings, mmu_booke_page_wired_mappings),
           MMUMETHOD(mmu_pinit,            mmu_booke_pinit),
           MMUMETHOD(mmu_pinit0,           mmu_booke_pinit0),
           MMUMETHOD(mmu_protect,          mmu_booke_protect),
           MMUMETHOD(mmu_qenter,           mmu_booke_qenter),
           MMUMETHOD(mmu_qremove,          mmu_booke_qremove),
           MMUMETHOD(mmu_release,          mmu_booke_release),
           MMUMETHOD(mmu_remove,           mmu_booke_remove),
           MMUMETHOD(mmu_remove_all,       mmu_booke_remove_all),
           MMUMETHOD(mmu_remove_write,     mmu_booke_remove_write),
           MMUMETHOD(mmu_sync_icache,      mmu_booke_sync_icache),
           MMUMETHOD(mmu_unwire,           mmu_booke_unwire),
           MMUMETHOD(mmu_zero_page,        mmu_booke_zero_page),
           MMUMETHOD(mmu_zero_page_area,   mmu_booke_zero_page_area),
           MMUMETHOD(mmu_zero_page_idle,   mmu_booke_zero_page_idle),
           MMUMETHOD(mmu_activate,         mmu_booke_activate),
           MMUMETHOD(mmu_deactivate,       mmu_booke_deactivate),
           MMUMETHOD(mmu_quick_enter_page, mmu_booke_quick_enter_page),
           MMUMETHOD(mmu_quick_remove_page, mmu_booke_quick_remove_page),
   
           /* Internal interfaces */
           MMUMETHOD(mmu_bootstrap,        mmu_booke_bootstrap),
           MMUMETHOD(mmu_dev_direct_mapped,mmu_booke_dev_direct_mapped),
           MMUMETHOD(mmu_mapdev,           mmu_booke_mapdev),
           MMUMETHOD(mmu_mapdev_attr,      mmu_booke_mapdev_attr),
           MMUMETHOD(mmu_kenter,           mmu_booke_kenter),
           MMUMETHOD(mmu_kenter_attr,      mmu_booke_kenter_attr),
           MMUMETHOD(mmu_kextract,         mmu_booke_kextract),
   /*      MMUMETHOD(mmu_kremove,          mmu_booke_kremove),     */
           MMUMETHOD(mmu_unmapdev,         mmu_booke_unmapdev),
           MMUMETHOD(mmu_change_attr,      mmu_booke_change_attr),
   
           /* dumpsys() support */
           MMUMETHOD(mmu_dumpsys_map,      mmu_booke_dumpsys_map),
           MMUMETHOD(mmu_dumpsys_unmap,    mmu_booke_dumpsys_unmap),
           MMUMETHOD(mmu_scan_init,        mmu_booke_scan_init),
   
           { 0, 0 }
   };
   
   MMU_DEF(booke_mmu, MMU_TYPE_BOOKE, mmu_booke_methods, 0);
   
   static __inline uint32_t
   tlb_calc_wimg(vm_paddr_t pa, vm_memattr_t ma)
   {
           uint32_t attrib;
           int i;
   
           if (ma != VM_MEMATTR_DEFAULT) {
                   switch (ma) {
                   case VM_MEMATTR_UNCACHEABLE:
                           return (MAS2_I | MAS2_G);
                   case VM_MEMATTR_WRITE_COMBINING:
                   case VM_MEMATTR_WRITE_BACK:
                   case VM_MEMATTR_PREFETCHABLE:
                           return (MAS2_I);
                   case VM_MEMATTR_WRITE_THROUGH:
                           return (MAS2_W | MAS2_M);
                   case VM_MEMATTR_CACHEABLE:
                           return (MAS2_M);
                   }
           }
   
           /*
            * Assume the page is cache inhibited and access is guarded unless
            * it's in our available memory array.
            */
           attrib = _TLB_ENTRY_IO;
           for (i = 0; i < physmem_regions_sz; i++) {
                   if ((pa >= physmem_regions[i].mr_start) &&
                       (pa < (physmem_regions[i].mr_start +
                        physmem_regions[i].mr_size))) {
                           attrib = _TLB_ENTRY_MEM;
                           break;
                   }
           }
   
           return (attrib);
   }
   
   static inline void
   tlb_miss_lock(void)
   {
   #ifdef SMP
           struct pcpu *pc;
   
           if (!smp_started)
                   return;
   
           STAILQ_FOREACH(pc, &cpuhead, pc_allcpu) {
                   if (pc != pcpup) {
   
                           CTR3(KTR_PMAP, "%s: tlb miss LOCK of CPU=%d, "
                               "tlb_lock=%p", __func__, pc->pc_cpuid, pc->pc_booke_tlb_lock);
   
                           KASSERT((pc->pc_cpuid != PCPU_GET(cpuid)),
                               ("tlb_miss_lock: tried to lock self"));
   
                           tlb_lock(pc->pc_booke_tlb_lock);
   
                           CTR1(KTR_PMAP, "%s: locked", __func__);
                   }
           }
   #endif
   }
   
   static inline void
   tlb_miss_unlock(void)
   {
   #ifdef SMP
           struct pcpu *pc;
   
           if (!smp_started)
                   return;
   
           STAILQ_FOREACH(pc, &cpuhead, pc_allcpu) {
                   if (pc != pcpup) {
                           CTR2(KTR_PMAP, "%s: tlb miss UNLOCK of CPU=%d",
                               __func__, pc->pc_cpuid);
   
                           tlb_unlock(pc->pc_booke_tlb_lock);
   
                           CTR1(KTR_PMAP, "%s: unlocked", __func__);
                   }
           }
   #endif
   }
   
   /* Return number of entries in TLB0. */
   static __inline void
   tlb0_get_tlbconf(void)
   {
           uint32_t tlb0_cfg;
   
           tlb0_cfg = mfspr(SPR_TLB0CFG);
           tlb0_entries = tlb0_cfg & TLBCFG_NENTRY_MASK;
           tlb0_ways = (tlb0_cfg & TLBCFG_ASSOC_MASK) >> TLBCFG_ASSOC_SHIFT;
           tlb0_entries_per_way = tlb0_entries / tlb0_ways;
   }
   
   /* Return number of entries in TLB1. */
   static __inline void
   tlb1_get_tlbconf(void)
   {
           uint32_t tlb1_cfg;
   
           tlb1_cfg = mfspr(SPR_TLB1CFG);
           tlb1_entries = tlb1_cfg & TLBCFG_NENTRY_MASK;
   }
   
   /**************************************************************************/
   /* Page table related */
   /**************************************************************************/
   
   /* Initialize pool of kva ptbl buffers. */
   static void
   ptbl_init(void)
   {
           int i;
   
           CTR3(KTR_PMAP, "%s: s (ptbl_bufs = 0x%08x size 0x%08x)", __func__,
               (uint32_t)ptbl_bufs, sizeof(struct ptbl_buf) * PTBL_BUFS);
           CTR3(KTR_PMAP, "%s: s (ptbl_buf_pool_vabase = 0x%08x size = 0x%08x)",
               __func__, ptbl_buf_pool_vabase, PTBL_BUFS * PTBL_PAGES * PAGE_SIZE);
   
           mtx_init(&ptbl_buf_freelist_lock, "ptbl bufs lock", NULL, MTX_DEF);
           TAILQ_INIT(&ptbl_buf_freelist);
   
           for (i = 0; i < PTBL_BUFS; i++) {
                   ptbl_bufs[i].kva = ptbl_buf_pool_vabase + i * PTBL_PAGES * PAGE_SIZE;
                   TAILQ_INSERT_TAIL(&ptbl_buf_freelist, &ptbl_bufs[i], link);
           }
   }
   
   /* Get a ptbl_buf from the freelist. */
   static struct ptbl_buf *
   ptbl_buf_alloc(void)
   {
           struct ptbl_buf *buf;
   
           mtx_lock(&ptbl_buf_freelist_lock);
           buf = TAILQ_FIRST(&ptbl_buf_freelist);
           if (buf != NULL)
                   TAILQ_REMOVE(&ptbl_buf_freelist, buf, link);
           mtx_unlock(&ptbl_buf_freelist_lock);
   
           CTR2(KTR_PMAP, "%s: buf = %p", __func__, buf);
   
           return (buf);
   }
   
   /* Return ptbl buff to free pool. */
   static void
   ptbl_buf_free(struct ptbl_buf *buf)
   {
   
           CTR2(KTR_PMAP, "%s: buf = %p", __func__, buf);
   
           mtx_lock(&ptbl_buf_freelist_lock);
           TAILQ_INSERT_TAIL(&ptbl_buf_freelist, buf, link);
           mtx_unlock(&ptbl_buf_freelist_lock);
   }
   
   /*
    * Search the list of allocated ptbl bufs and find on list of allocated ptbls
    */
   static void
   ptbl_free_pmap_ptbl(pmap_t pmap, pte_t *ptbl)
   {
           struct ptbl_buf *pbuf;
   
           CTR2(KTR_PMAP, "%s: ptbl = %p", __func__, ptbl);
   
           PMAP_LOCK_ASSERT(pmap, MA_OWNED);
   
           TAILQ_FOREACH(pbuf, &pmap->pm_ptbl_list, link)
                   if (pbuf->kva == (vm_offset_t)ptbl) {
                           /* Remove from pmap ptbl buf list. */
                           TAILQ_REMOVE(&pmap->pm_ptbl_list, pbuf, link);
   
                           /* Free corresponding ptbl buf. */
                           ptbl_buf_free(pbuf);
                           break;
                   }
   }
   
   /* Allocate page table. */
   static pte_t *
   ptbl_alloc(mmu_t mmu, pmap_t pmap, unsigned int pdir_idx, boolean_t nosleep)
   {
           vm_page_t mtbl[PTBL_PAGES];
           vm_page_t m;
           struct ptbl_buf *pbuf;
           unsigned int pidx;
           pte_t *ptbl;
           int i, j;
   
           CTR4(KTR_PMAP, "%s: pmap = %p su = %d pdir_idx = %d", __func__, pmap,
               (pmap == kernel_pmap), pdir_idx);
   
           KASSERT((pdir_idx <= (VM_MAXUSER_ADDRESS / PDIR_SIZE)),
               ("ptbl_alloc: invalid pdir_idx"));
           KASSERT((pmap->pm_pdir[pdir_idx] == NULL),
               ("pte_alloc: valid ptbl entry exists!"));
   
           pbuf = ptbl_buf_alloc();
           if (pbuf == NULL)
                   panic("pte_alloc: couldn't alloc kernel virtual memory");
                   
           ptbl = (pte_t *)pbuf->kva;
   
           CTR2(KTR_PMAP, "%s: ptbl kva = %p", __func__, ptbl);
   
           /* Allocate ptbl pages, this will sleep! */
           for (i = 0; i < PTBL_PAGES; i++) {
                   pidx = (PTBL_PAGES * pdir_idx) + i;
                   while ((m = vm_page_alloc(NULL, pidx,
                       VM_ALLOC_NOOBJ | VM_ALLOC_WIRED)) == NULL) {
                           PMAP_UNLOCK(pmap);
                           rw_wunlock(&pvh_global_lock);
                           if (nosleep) {
                                   ptbl_free_pmap_ptbl(pmap, ptbl);
                                   for (j = 0; j < i; j++)
                                           vm_page_free(mtbl[j]);
                                   atomic_subtract_int(&vm_cnt.v_wire_count, i);
                                   return (NULL);
                           }
                           VM_WAIT;
                           rw_wlock(&pvh_global_lock);
                           PMAP_LOCK(pmap);
                   }
                   mtbl[i] = m;
           }
   
           /* Map allocated pages into kernel_pmap. */
           mmu_booke_qenter(mmu, (vm_offset_t)ptbl, mtbl, PTBL_PAGES);
   
           /* Zero whole ptbl. */
           bzero((caddr_t)ptbl, PTBL_PAGES * PAGE_SIZE);
   
           /* Add pbuf to the pmap ptbl bufs list. */
           TAILQ_INSERT_TAIL(&pmap->pm_ptbl_list, pbuf, link);
   
           return (ptbl);
   }
   
   /* Free ptbl pages and invalidate pdir entry. */
   static void
   ptbl_free(mmu_t mmu, pmap_t pmap, unsigned int pdir_idx)
   {
           pte_t *ptbl;
           vm_paddr_t pa;
           vm_offset_t va;
           vm_page_t m;
           int i;
   
           CTR4(KTR_PMAP, "%s: pmap = %p su = %d pdir_idx = %d", __func__, pmap,
               (pmap == kernel_pmap), pdir_idx);
   
           KASSERT((pdir_idx <= (VM_MAXUSER_ADDRESS / PDIR_SIZE)),
               ("ptbl_free: invalid pdir_idx"));
   
           ptbl = pmap->pm_pdir[pdir_idx];
   
           CTR2(KTR_PMAP, "%s: ptbl = %p", __func__, ptbl);
   
           KASSERT((ptbl != NULL), ("ptbl_free: null ptbl"));
   
           /*
            * Invalidate the pdir entry as soon as possible, so that other CPUs
            * don't attempt to look up the page tables we are releasing.
            */
           mtx_lock_spin(&tlbivax_mutex);
           tlb_miss_lock();
           
           pmap->pm_pdir[pdir_idx] = NULL;
   
           tlb_miss_unlock();
           mtx_unlock_spin(&tlbivax_mutex);
   
           for (i = 0; i < PTBL_PAGES; i++) {
                   va = ((vm_offset_t)ptbl + (i * PAGE_SIZE));
                   pa = pte_vatopa(mmu, kernel_pmap, va);
                   m = PHYS_TO_VM_PAGE(pa);
                   vm_page_free_zero(m);
                   atomic_subtract_int(&vm_cnt.v_wire_count, 1);
                   mmu_booke_kremove(mmu, va);
           }
   
           ptbl_free_pmap_ptbl(pmap, ptbl);
   }
   
   /*
    * Decrement ptbl pages hold count and attempt to free ptbl pages.
    * Called when removing pte entry from ptbl.
    *
    * Return 1 if ptbl pages were freed.
    */
   static int
   ptbl_unhold(mmu_t mmu, pmap_t pmap, unsigned int pdir_idx)
   {
           pte_t *ptbl;
           vm_paddr_t pa;
           vm_page_t m;
           int i;
   
           CTR4(KTR_PMAP, "%s: pmap = %p su = %d pdir_idx = %d", __func__, pmap,
               (pmap == kernel_pmap), pdir_idx);
   
           KASSERT((pdir_idx <= (VM_MAXUSER_ADDRESS / PDIR_SIZE)),
               ("ptbl_unhold: invalid pdir_idx"));
           KASSERT((pmap != kernel_pmap),
               ("ptbl_unhold: unholding kernel ptbl!"));
   
           ptbl = pmap->pm_pdir[pdir_idx];
   
           //debugf("ptbl_unhold: ptbl = 0x%08x\n", (u_int32_t)ptbl);
           KASSERT(((vm_offset_t)ptbl >= VM_MIN_KERNEL_ADDRESS),
               ("ptbl_unhold: non kva ptbl"));
   
           /* decrement hold count */
           for (i = 0; i < PTBL_PAGES; i++) {
                   pa = pte_vatopa(mmu, kernel_pmap,
                       (vm_offset_t)ptbl + (i * PAGE_SIZE));
                   m = PHYS_TO_VM_PAGE(pa);
                   m->wire_count--;
           }
   
           /*
            * Free ptbl pages if there are no pte etries in this ptbl.
            * wire_count has the same value for all ptbl pages, so check the last
            * page.
            */
           if (m->wire_count == 0) {
                   ptbl_free(mmu, pmap, pdir_idx);
   
                   //debugf("ptbl_unhold: e (freed ptbl)\n");
                   return (1);
           }
   
           return (0);
   }
   
   /*
    * Increment hold count for ptbl pages. This routine is used when a new pte
    * entry is being inserted into the ptbl.
    */
   static void
   ptbl_hold(mmu_t mmu, pmap_t pmap, unsigned int pdir_idx)
   {
           vm_paddr_t pa;
           pte_t *ptbl;
           vm_page_t m;
           int i;
   
           CTR3(KTR_PMAP, "%s: pmap = %p pdir_idx = %d", __func__, pmap,
               pdir_idx);
   
           KASSERT((pdir_idx <= (VM_MAXUSER_ADDRESS / PDIR_SIZE)),
               ("ptbl_hold: invalid pdir_idx"));
           KASSERT((pmap != kernel_pmap),
               ("ptbl_hold: holding kernel ptbl!"));
   
           ptbl = pmap->pm_pdir[pdir_idx];
   
           KASSERT((ptbl != NULL), ("ptbl_hold: null ptbl"));
   
           for (i = 0; i < PTBL_PAGES; i++) {
                   pa = pte_vatopa(mmu, kernel_pmap,
                       (vm_offset_t)ptbl + (i * PAGE_SIZE));
                   m = PHYS_TO_VM_PAGE(pa);
                   m->wire_count++;
           }
   }
   
   /* Allocate pv_entry structure. */
   pv_entry_t
   pv_alloc(void)
   {
           pv_entry_t pv;
   
           pv_entry_count++;
           if (pv_entry_count > pv_entry_high_water)
                   pagedaemon_wakeup();
           pv = uma_zalloc(pvzone, M_NOWAIT);
   
           return (pv);
   }
   
   /* Free pv_entry structure. */
   static __inline void
   pv_free(pv_entry_t pve)
   {
   
           pv_entry_count--;
           uma_zfree(pvzone, pve);
   }
   
   
   /* Allocate and initialize pv_entry structure. */
   static void
   pv_insert(pmap_t pmap, vm_offset_t va, vm_page_t m)
   {
           pv_entry_t pve;
   
           //int su = (pmap == kernel_pmap);
           //debugf("pv_insert: s (su = %d pmap = 0x%08x va = 0x%08x m = 0x%08x)\n", su,
           //      (u_int32_t)pmap, va, (u_int32_t)m);
   
           pve = pv_alloc();
           if (pve == NULL)
                   panic("pv_insert: no pv entries!");
   
           pve->pv_pmap = pmap;
           pve->pv_va = va;
   
           /* add to pv_list */
           PMAP_LOCK_ASSERT(pmap, MA_OWNED);
           rw_assert(&pvh_global_lock, RA_WLOCKED);
   
           TAILQ_INSERT_TAIL(&m->md.pv_list, pve, pv_link);
   
           //debugf("pv_insert: e\n");
   }
   
   /* Destroy pv entry. */
   static void
   pv_remove(pmap_t pmap, vm_offset_t va, vm_page_t m)
   {
           pv_entry_t pve;
   
           //int su = (pmap == kernel_pmap);
           //debugf("pv_remove: s (su = %d pmap = 0x%08x va = 0x%08x)\n", su, (u_int32_t)pmap, va);
   
           PMAP_LOCK_ASSERT(pmap, MA_OWNED);
           rw_assert(&pvh_global_lock, RA_WLOCKED);
   
           /* find pv entry */
           TAILQ_FOREACH(pve, &m->md.pv_list, pv_link) {
                   if ((pmap == pve->pv_pmap) && (va == pve->pv_va)) {
                           /* remove from pv_list */
                           TAILQ_REMOVE(&m->md.pv_list, pve, pv_link);
                           if (TAILQ_EMPTY(&m->md.pv_list))
                                   vm_page_aflag_clear(m, PGA_WRITEABLE);
   
                           /* free pv entry struct */
                           pv_free(pve);
                           break;
                   }
           }
   
           //debugf("pv_remove: e\n");
   }
   
   /*
    * Clean pte entry, try to free page table page if requested.
    *
    * Return 1 if ptbl pages were freed, otherwise return 0.
    */
   static int
   pte_remove(mmu_t mmu, pmap_t pmap, vm_offset_t va, uint8_t flags)
   {
           unsigned int pdir_idx = PDIR_IDX(va);
           unsigned int ptbl_idx = PTBL_IDX(va);
           vm_page_t m;
           pte_t *ptbl;
           pte_t *pte;
   
           //int su = (pmap == kernel_pmap);
           //debugf("pte_remove: s (su = %d pmap = 0x%08x va = 0x%08x flags = %d)\n",
           //              su, (u_int32_t)pmap, va, flags);
   
           ptbl = pmap->pm_pdir[pdir_idx];
           KASSERT(ptbl, ("pte_remove: null ptbl"));
   
           pte = &ptbl[ptbl_idx];
   
           if (pte == NULL || !PTE_ISVALID(pte))
                   return (0);
   
           if (PTE_ISWIRED(pte))
                   pmap->pm_stats.wired_count--;
   
           /* Handle managed entry. */
           if (PTE_ISMANAGED(pte)) {
                   /* Get vm_page_t for mapped pte. */
                   m = PHYS_TO_VM_PAGE(PTE_PA(pte));
   
                   if (PTE_ISMODIFIED(pte))
                           vm_page_dirty(m);
   
                   if (PTE_ISREFERENCED(pte))
                           vm_page_aflag_set(m, PGA_REFERENCED);
   
                   pv_remove(pmap, va, m);
           }
   
           mtx_lock_spin(&tlbivax_mutex);
           tlb_miss_lock();
   
           tlb0_flush_entry(va);
           *pte = 0;
   
           tlb_miss_unlock();
           mtx_unlock_spin(&tlbivax_mutex);
   
           pmap->pm_stats.resident_count--;
   
           if (flags & PTBL_UNHOLD) {
                   //debugf("pte_remove: e (unhold)\n");
                   return (ptbl_unhold(mmu, pmap, pdir_idx));
           }
   
           //debugf("pte_remove: e\n");
           return (0);
   }
   
   /*
    * Insert PTE for a given page and virtual address.
    */
   static int
   pte_enter(mmu_t mmu, pmap_t pmap, vm_page_t m, vm_offset_t va, uint32_t flags,
       boolean_t nosleep)
   {
           unsigned int pdir_idx = PDIR_IDX(va);
           unsigned int ptbl_idx = PTBL_IDX(va);
           pte_t *ptbl, *pte;
   
           CTR4(KTR_PMAP, "%s: su = %d pmap = %p va = %p", __func__,
               pmap == kernel_pmap, pmap, va);
   
           /* Get the page table pointer. */
           ptbl = pmap->pm_pdir[pdir_idx];
   
           if (ptbl == NULL) {
                   /* Allocate page table pages. */
                   ptbl = ptbl_alloc(mmu, pmap, pdir_idx, nosleep);
                   if (ptbl == NULL) {
                           KASSERT(nosleep, ("nosleep and NULL ptbl"));
                           return (ENOMEM);
                   }
           } else {
                   /*
                    * Check if there is valid mapping for requested
                    * va, if there is, remove it.
                    */
                   pte = &pmap->pm_pdir[pdir_idx][ptbl_idx];
                   if (PTE_ISVALID(pte)) {
                           pte_remove(mmu, pmap, va, PTBL_HOLD);
                   } else {
                           /*
                            * pte is not used, increment hold count
                            * for ptbl pages.
                            */
                           if (pmap != kernel_pmap)
                                   ptbl_hold(mmu, pmap, pdir_idx);
                   }
           }
   
           /*
            * Insert pv_entry into pv_list for mapped page if part of managed
            * memory.
            */
           if ((m->oflags & VPO_UNMANAGED) == 0) {
                   flags |= PTE_MANAGED;
   
                   /* Create and insert pv entry. */
                   pv_insert(pmap, va, m);
           }
   
           pmap->pm_stats.resident_count++;
           
           mtx_lock_spin(&tlbivax_mutex);
           tlb_miss_lock();
   
           tlb0_flush_entry(va);
           if (pmap->pm_pdir[pdir_idx] == NULL) {
                   /*
                    * If we just allocated a new page table, hook it in
                    * the pdir.
                    */
                   pmap->pm_pdir[pdir_idx] = ptbl;
           }
           pte = &(pmap->pm_pdir[pdir_idx][ptbl_idx]);
           *pte = PTE_RPN_FROM_PA(VM_PAGE_TO_PHYS(m));
           *pte |= (PTE_VALID | flags | PTE_PS_4KB); /* 4KB pages only */
   
           tlb_miss_unlock();
           mtx_unlock_spin(&tlbivax_mutex);
           return (0);
   }
   
   /* Return the pa for the given pmap/va. */
   static vm_paddr_t
   pte_vatopa(mmu_t mmu, pmap_t pmap, vm_offset_t va)
   {
           vm_paddr_t pa = 0;
           pte_t *pte;
   
           pte = pte_find(mmu, pmap, va);
          if ((pte != NULL) && PTE_ISVALID(pte))
                  pa = (PTE_PA(pte) | (va & PTE_PA_MASK));
          return (pa);
  }
  
  /* Get a pointer to a PTE in a page table. */
  static pte_t *
  pte_find(mmu_t mmu, pmap_t pmap, vm_offset_t va)
  {
          unsigned int pdir_idx = PDIR_IDX(va);
          unsigned int ptbl_idx = PTBL_IDX(va);
  
          KASSERT((pmap != NULL), ("pte_find: invalid pmap"));
  
          if (pmap->pm_pdir[pdir_idx])
                  return (&(pmap->pm_pdir[pdir_idx][ptbl_idx]));
  
          return (NULL);
  }
  
  /* Set up kernel page tables. */
  static void
  kernel_pte_alloc(vm_offset_t data_end, vm_offset_t addr, vm_offset_t pdir)
  {
          int             i;
          vm_offset_t     va;
          pte_t           *pte;
  
          /* Initialize kernel pdir */
          for (i = 0; i < kernel_ptbls; i++)
                  kernel_pmap->pm_pdir[kptbl_min + i] =
                      (pte_t *)(pdir + (i * PAGE_SIZE * PTBL_PAGES));
  
          /*
           * Fill in PTEs covering kernel code and data. They are not required
           * for address translation, as this area is covered by static TLB1
           * entries, but for pte_vatopa() to work correctly with kernel area
           * addresses.
           */
          for (va = addr; va < data_end; va += PAGE_SIZE) {
                  pte = &(kernel_pmap->pm_pdir[PDIR_IDX(va)][PTBL_IDX(va)]);
                  *pte = PTE_RPN_FROM_PA(kernload + (va - kernstart));
                  *pte |= PTE_M | PTE_SR | PTE_SW | PTE_SX | PTE_WIRED |
                      PTE_VALID | PTE_PS_4KB;
          }
  }
  
  /**************************************************************************/
  /* PMAP related */
  /**************************************************************************/
  
  /*
   * This is called during booke_init, before the system is really initialized.
   */
  static void
  mmu_booke_bootstrap(mmu_t mmu, vm_offset_t start, vm_offset_t kernelend)
  {
          vm_paddr_t phys_kernelend;
          struct mem_region *mp, *mp1;
          int cnt, i, j;
          vm_paddr_t s, e, sz;
          vm_paddr_t physsz, hwphyssz;
          u_int phys_avail_count;
          vm_size_t kstack0_sz;
          vm_offset_t kernel_pdir, kstack0;
          vm_paddr_t kstack0_phys;
          void *dpcpu;
  
          debugf("mmu_booke_bootstrap: entered\n");
  
          /* Set interesting system properties */
          hw_direct_map = 0;
          elf32_nxstack = 1;
  
          /* Initialize invalidation mutex */
          mtx_init(&tlbivax_mutex, "tlbivax", NULL, MTX_SPIN);
  
          /* Read TLB0 size and associativity. */
          tlb0_get_tlbconf();
  
          /*
           * Align kernel start and end address (kernel image).
           * Note that kernel end does not necessarily relate to kernsize.
           * kernsize is the size of the kernel that is actually mapped.
           */
          kernstart = trunc_page(start);
          data_start = round_page(kernelend);
          data_end = data_start;
  
          /*
           * Addresses of preloaded modules (like file systems) use
           * physical addresses. Make sure we relocate those into
           * virtual addresses.
           */
          preload_addr_relocate = kernstart - kernload;
  
          /* Allocate the dynamic per-cpu area. */
          dpcpu = (void *)data_end;
          data_end += DPCPU_SIZE;
  
          /* Allocate space for the message buffer. */
          msgbufp = (struct msgbuf *)data_end;
          data_end += msgbufsize;
          debugf(" msgbufp at 0x%08x end = 0x%08x\n", (uint32_t)msgbufp,
              data_end);
  
          data_end = round_page(data_end);
  
          /* Allocate space for ptbl_bufs. */
          ptbl_bufs = (struct ptbl_buf *)data_end;
          data_end += sizeof(struct ptbl_buf) * PTBL_BUFS;
          debugf(" ptbl_bufs at 0x%08x end = 0x%08x\n", (uint32_t)ptbl_bufs,
              data_end);
  
          data_end = round_page(data_end);
  
          /* Allocate PTE tables for kernel KVA. */
          kernel_pdir = data_end;
          kernel_ptbls = howmany(VM_MAX_KERNEL_ADDRESS - VM_MIN_KERNEL_ADDRESS,
              PDIR_SIZE);
          data_end += kernel_ptbls * PTBL_PAGES * PAGE_SIZE;
          debugf(" kernel ptbls: %d\n", kernel_ptbls);
          debugf(" kernel pdir at 0x%08x end = 0x%08x\n", kernel_pdir, data_end);
  
          debugf(" data_end: 0x%08x\n", data_end);
          if (data_end - kernstart > kernsize) {
                  kernsize += tlb1_mapin_region(kernstart + kernsize,
                      kernload + kernsize, (data_end - kernstart) - kernsize);
          }
          data_end = kernstart + kernsize;
          debugf(" updated data_end: 0x%08x\n", data_end);
  
          /*
           * Clear the structures - note we can only do it safely after the
           * possible additional TLB1 translations are in place (above) so that
           * all range up to the currently calculated 'data_end' is covered.
           */
          dpcpu_init(dpcpu, 0);
          memset((void *)ptbl_bufs, 0, sizeof(struct ptbl_buf) * PTBL_SIZE);
          memset((void *)kernel_pdir, 0, kernel_ptbls * PTBL_PAGES * PAGE_SIZE);
  
          /*******************************************************/
          /* Set the start and end of kva. */
          /*******************************************************/
          virtual_avail = round_page(data_end);
          virtual_end = VM_MAX_KERNEL_ADDRESS;
  
          /* Allocate KVA space for page zero/copy operations. */
          zero_page_va = virtual_avail;
          virtual_avail += PAGE_SIZE;
          zero_page_idle_va = virtual_avail;
          virtual_avail += PAGE_SIZE;
          copy_page_src_va = virtual_avail;
          virtual_avail += PAGE_SIZE;
          copy_page_dst_va = virtual_avail;
          virtual_avail += PAGE_SIZE;
          debugf("zero_page_va = 0x%08x\n", zero_page_va);
          debugf("zero_page_idle_va = 0x%08x\n", zero_page_idle_va);
          debugf("copy_page_src_va = 0x%08x\n", copy_page_src_va);
          debugf("copy_page_dst_va = 0x%08x\n", copy_page_dst_va);
  
          /* Initialize page zero/copy mutexes. */
          mtx_init(&zero_page_mutex, "mmu_booke_zero_page", NULL, MTX_DEF);
          mtx_init(&copy_page_mutex, "mmu_booke_copy_page", NULL, MTX_DEF);
  
          /* Allocate KVA space for ptbl bufs. */
          ptbl_buf_pool_vabase = virtual_avail;
          virtual_avail += PTBL_BUFS * PTBL_PAGES * PAGE_SIZE;
          debugf("ptbl_buf_pool_vabase = 0x%08x end = 0x%08x\n",
              ptbl_buf_pool_vabase, virtual_avail);
  
          /* Calculate corresponding physical addresses for the kernel region. */
          phys_kernelend = kernload + kernsize;
          debugf("kernel image and allocated data:\n");
          debugf(" kernload    = 0x%09llx\n", (uint64_t)kernload);
          debugf(" kernstart   = 0x%08x\n", kernstart);
          debugf(" kernsize    = 0x%08x\n", kernsize);
  
          if (sizeof(phys_avail) / sizeof(phys_avail[0]) < availmem_regions_sz)
                  panic("mmu_booke_bootstrap: phys_avail too small");
  
          /*
           * Remove kernel physical address range from avail regions list. Page
           * align all regions.  Non-page aligned memory isn't very interesting
           * to us.  Also, sort the entries for ascending addresses.
           */
  
          /* Retrieve phys/avail mem regions */
          mem_regions(&physmem_regions, &physmem_regions_sz,
              &availmem_regions, &availmem_regions_sz);
          sz = 0;
          cnt = availmem_regions_sz;
          debugf("processing avail regions:\n");
          for (mp = availmem_regions; mp->mr_size; mp++) {
                  s = mp->mr_start;
                  e = mp->mr_start + mp->mr_size;
                  debugf(" %09jx-%09jx -> ", (uintmax_t)s, (uintmax_t)e);
                  /* Check whether this region holds all of the kernel. */
                  if (s < kernload && e > phys_kernelend) {
                          availmem_regions[cnt].mr_start = phys_kernelend;
                          availmem_regions[cnt++].mr_size = e - phys_kernelend;
                          e = kernload;
                  }
                  /* Look whether this regions starts within the kernel. */
                  if (s >= kernload && s < phys_kernelend) {
                          if (e <= phys_kernelend)
                                  goto empty;
                          s = phys_kernelend;
                  }
                  /* Now look whether this region ends within the kernel. */
                  if (e > kernload && e <= phys_kernelend) {
                          if (s >= kernload)
                                  goto empty;
                          e = kernload;
                  }
                  /* Now page align the start and size of the region. */
                  s = round_page(s);
                  e = trunc_page(e);
                  if (e < s)
                          e = s;
                  sz = e - s;
                  debugf("%09jx-%09jx = %jx\n",
                      (uintmax_t)s, (uintmax_t)e, (uintmax_t)sz);
  
                  /* Check whether some memory is left here. */
                  if (sz == 0) {
                  empty:
                          memmove(mp, mp + 1,
                              (cnt - (mp - availmem_regions)) * sizeof(*mp));
                          cnt--;
                          mp--;
                          continue;
                  }
  
                  /* Do an insertion sort. */
                  for (mp1 = availmem_regions; mp1 < mp; mp1++)
                          if (s < mp1->mr_start)
                                  break;
                  if (mp1 < mp) {
                          memmove(mp1 + 1, mp1, (char *)mp - (char *)mp1);
                          mp1->mr_start = s;
                          mp1->mr_size = sz;
                  } else {
                          mp->mr_start = s;
                          mp->mr_size = sz;
                  }
          }
          availmem_regions_sz = cnt;
  
          /*******************************************************/
          /* Steal physical memory for kernel stack from the end */
          /* of the first avail region                           */
          /*******************************************************/
          kstack0_sz = kstack_pages * PAGE_SIZE;
          kstack0_phys = availmem_regions[0].mr_start +
              availmem_regions[0].mr_size;
          kstack0_phys -= kstack0_sz;
          availmem_regions[0].mr_size -= kstack0_sz;
  
          /*******************************************************/
          /* Fill in phys_avail table, based on availmem_regions */
          /*******************************************************/
          phys_avail_count = 0;
          physsz = 0;
          hwphyssz = 0;
          TUNABLE_ULONG_FETCH("hw.physmem", (u_long *) &hwphyssz);
  
          debugf("fill in phys_avail:\n");
          for (i = 0, j = 0; i < availmem_regions_sz; i++, j += 2) {
  
                  debugf(" region: 0x%jx - 0x%jx (0x%jx)\n",
                      (uintmax_t)availmem_regions[i].mr_start,
                      (uintmax_t)availmem_regions[i].mr_start +
                          availmem_regions[i].mr_size,
                      (uintmax_t)availmem_regions[i].mr_size);
  
                  if (hwphyssz != 0 &&
                      (physsz + availmem_regions[i].mr_size) >= hwphyssz) {
                          debugf(" hw.physmem adjust\n");
                          if (physsz < hwphyssz) {
                                  phys_avail[j] = availmem_regions[i].mr_start;
                                  phys_avail[j + 1] =
                                      availmem_regions[i].mr_start +
                                      hwphyssz - physsz;
                                  physsz = hwphyssz;
                                  phys_avail_count++;
                          }
                          break;
                  }
  
                  phys_avail[j] = availmem_regions[i].mr_start;
                  phys_avail[j + 1] = availmem_regions[i].mr_start +
                      availmem_regions[i].mr_size;
                  phys_avail_count++;
                  physsz += availmem_regions[i].mr_size;
          }
          physmem = btoc(physsz);
  
          /* Calculate the last available physical address. */
          for (i = 0; phys_avail[i + 2] != 0; i += 2)
                  ;
          Maxmem = powerpc_btop(phys_avail[i + 1]);
  
          debugf("Maxmem = 0x%08lx\n", Maxmem);
          debugf("phys_avail_count = %d\n", phys_avail_count);
          debugf("physsz = 0x%09jx physmem = %jd (0x%09jx)\n",
              (uintmax_t)physsz, (uintmax_t)physmem, (uintmax_t)physmem);
  
          /*******************************************************/
          /* Initialize (statically allocated) kernel pmap. */
          /*******************************************************/
          PMAP_LOCK_INIT(kernel_pmap);
          kptbl_min = VM_MIN_KERNEL_ADDRESS / PDIR_SIZE;
  
          debugf("kernel_pmap = 0x%08x\n", (uint32_t)kernel_pmap);
          debugf("kptbl_min = %d, kernel_ptbls = %d\n", kptbl_min, kernel_ptbls);
          debugf("kernel pdir range: 0x%08x - 0x%08x\n",
              kptbl_min * PDIR_SIZE, (kptbl_min + kernel_ptbls) * PDIR_SIZE - 1);
  
          kernel_pte_alloc(data_end, kernstart, kernel_pdir);
          for (i = 0; i < MAXCPU; i++) {
                  kernel_pmap->pm_tid[i] = TID_KERNEL;
                  
                  /* Initialize each CPU's tidbusy entry 0 with kernel_pmap */
                  tidbusy[i][TID_KERNEL] = kernel_pmap;
          }
  
          /* Mark kernel_pmap active on all CPUs */
          CPU_FILL(&kernel_pmap->pm_active);
  
          /*
           * Initialize the global pv list lock.
           */
          rw_init(&pvh_global_lock, "pmap pv global");
  
          /*******************************************************/
          /* Final setup */
          /*******************************************************/
  
          /* Enter kstack0 into kernel map, provide guard page */
          kstack0 = virtual_avail + KSTACK_GUARD_PAGES * PAGE_SIZE;
          thread0.td_kstack = kstack0;
          thread0.td_kstack_pages = kstack_pages;
  
          debugf("kstack_sz = 0x%08x\n", kstack0_sz);
          debugf("kstack0_phys at 0x%09llx - 0x%09llx\n",
              kstack0_phys, kstack0_phys + kstack0_sz);
          debugf("kstack0 at 0x%08x - 0x%08x\n", kstack0, kstack0 + kstack0_sz);
          
          virtual_avail += KSTACK_GUARD_PAGES * PAGE_SIZE + kstack0_sz;
          for (i = 0; i < kstack_pages; i++) {
                  mmu_booke_kenter(mmu, kstack0, kstack0_phys);
                  kstack0 += PAGE_SIZE;
                  kstack0_phys += PAGE_SIZE;
          }
  
          pmap_bootstrapped = 1;
          
          debugf("virtual_avail = %08x\n", virtual_avail);
          debugf("virtual_end   = %08x\n", virtual_end);
  
          debugf("mmu_booke_bootstrap: exit\n");
  }
  
  #ifdef SMP
   void
  tlb1_ap_prep(void)
  {
          tlb_entry_t *e, tmp;
          unsigned int i;
  
          /* Prepare TLB1 image for AP processors */
          e = __boot_tlb1;
          for (i = 0; i < TLB1_ENTRIES; i++) {
                  tlb1_read_entry(&tmp, i);
  
                  if ((tmp.mas1 & MAS1_VALID) && (tmp.mas2 & _TLB_ENTRY_SHARED))
                          memcpy(e++, &tmp, sizeof(tmp));
          }
  }
  
  void
  pmap_bootstrap_ap(volatile uint32_t *trcp __unused)
  {
          int i;
  
          /*
           * Finish TLB1 configuration: the BSP already set up its TLB1 and we
           * have the snapshot of its contents in the s/w __boot_tlb1[] table
           * created by tlb1_ap_prep(), so use these values directly to
           * (re)program AP's TLB1 hardware.
           *
           * Start at index 1 because index 0 has the kernel map.
           */
          for (i = 1; i < TLB1_ENTRIES; i++) {
                  if (__boot_tlb1[i].mas1 & MAS1_VALID)
                          tlb1_write_entry(&__boot_tlb1[i], i);
          }
  
          set_mas4_defaults();
  }
  #endif
  
  static void
  booke_pmap_init_qpages(void)
  {
          struct pcpu *pc;
          int i;
  
          CPU_FOREACH(i) {
                  pc = pcpu_find(i);
                  pc->pc_qmap_addr = kva_alloc(PAGE_SIZE);
                  if (pc->pc_qmap_addr == 0)
                          panic("pmap_init_qpages: unable to allocate KVA");
          }
  }
  
  SYSINIT(qpages_init, SI_SUB_CPU, SI_ORDER_ANY, booke_pmap_init_qpages, NULL);
  
  /*
   * Get the physical page address for the given pmap/virtual address.
   */
  static vm_paddr_t
  mmu_booke_extract(mmu_t mmu, pmap_t pmap, vm_offset_t va)
  {
          vm_paddr_t pa;
  
          PMAP_LOCK(pmap);
          pa = pte_vatopa(mmu, pmap, va);
          PMAP_UNLOCK(pmap);
  
          return (pa);
  }
  
  /*
   * Extract the physical page address associated with the given
   * kernel virtual address.
   */
  static vm_paddr_t
  mmu_booke_kextract(mmu_t mmu, vm_offset_t va)
  {
          tlb_entry_t e;
          int i;
  
          /* Check TLB1 mappings */
          for (i = 0; i < TLB1_ENTRIES; i++) {
                  tlb1_read_entry(&e, i);
                  if (!(e.mas1 & MAS1_VALID))
                          continue;
                  if (va >= e.virt && va < e.virt + e.size)
                          return (e.phys + (va - e.virt));
          }
  
          return (pte_vatopa(mmu, kernel_pmap, va));
  }
  
  /*
   * Initialize the pmap module.
   * Called by vm_init, to initialize any structures that the pmap
   * system needs to map virtual memory.
   */
  static void
  mmu_booke_init(mmu_t mmu)
  {
          int shpgperproc = PMAP_SHPGPERPROC;
  
          /*
           * Initialize the address space (zone) for the pv entries.  Set a
           * high water mark so that the system can recover from excessive
           * numbers of pv entries.
           */
          pvzone = uma_zcreate("PV ENTRY", sizeof(struct pv_entry), NULL, NULL,
              NULL, NULL, UMA_ALIGN_PTR, UMA_ZONE_VM | UMA_ZONE_NOFREE);
  
          TUNABLE_INT_FETCH("vm.pmap.shpgperproc", &shpgperproc);
          pv_entry_max = shpgperproc * maxproc + vm_cnt.v_page_count;
  
          TUNABLE_INT_FETCH("vm.pmap.pv_entries", &pv_entry_max);
          pv_entry_high_water = 9 * (pv_entry_max / 10);
  
          uma_zone_reserve_kva(pvzone, pv_entry_max);
  
          /* Pre-fill pvzone with initial number of pv entries. */
          uma_prealloc(pvzone, PV_ENTRY_ZONE_MIN);
  
          /* Initialize ptbl allocation. */
          ptbl_init();
  }
  
  /*
   * Map a list of wired pages into kernel virtual address space.  This is
   * intended for temporary mappings which do not need page modification or
   * references recorded.  Existing mappings in the region are overwritten.
   */
  static void
  mmu_booke_qenter(mmu_t mmu, vm_offset_t sva, vm_page_t *m, int count)
  {
          vm_offset_t va;
  
          va = sva;
          while (count-- > 0) {
                  mmu_booke_kenter(mmu, va, VM_PAGE_TO_PHYS(*m));
                  va += PAGE_SIZE;
                  m++;
          }
  }
  
  /*
   * Remove page mappings from kernel virtual address space.  Intended for
   * temporary mappings entered by mmu_booke_qenter.
   */
  static void
  mmu_booke_qremove(mmu_t mmu, vm_offset_t sva, int count)
  {
          vm_offset_t va;
  
          va = sva;
          while (count-- > 0) {
                  mmu_booke_kremove(mmu, va);
                  va += PAGE_SIZE;
          }
  }
  
  /*
   * Map a wired page into kernel virtual address space.
   */
  static void
  mmu_booke_kenter(mmu_t mmu, vm_offset_t va, vm_paddr_t pa)
  {
  
          mmu_booke_kenter_attr(mmu, va, pa, VM_MEMATTR_DEFAULT);
  }
  
  static void
  mmu_booke_kenter_attr(mmu_t mmu, vm_offset_t va, vm_paddr_t pa, vm_memattr_t ma)
  {
          uint32_t flags;
          pte_t *pte;
  
          KASSERT(((va >= VM_MIN_KERNEL_ADDRESS) &&
              (va <= VM_MAX_KERNEL_ADDRESS)), ("mmu_booke_kenter: invalid va"));
  
          flags = PTE_SR | PTE_SW | PTE_SX | PTE_WIRED | PTE_VALID;
          flags |= tlb_calc_wimg(pa, ma) << PTE_MAS2_SHIFT;
          flags |= PTE_PS_4KB;
  
          pte = pte_find(mmu, kernel_pmap, va);
  
          mtx_lock_spin(&tlbivax_mutex);
          tlb_miss_lock();
          
          if (PTE_ISVALID(pte)) {
          
                  CTR1(KTR_PMAP, "%s: replacing entry!", __func__);
  
                  /* Flush entry from TLB0 */
                  tlb0_flush_entry(va);
          }
  
          *pte = PTE_RPN_FROM_PA(pa) | flags;
  
          //debugf("mmu_booke_kenter: pdir_idx = %d ptbl_idx = %d va=0x%08x "
          //              "pa=0x%08x rpn=0x%08x flags=0x%08x\n",
          //              pdir_idx, ptbl_idx, va, pa, pte->rpn, pte->flags);
  
          /* Flush the real memory from the instruction cache. */
          if ((flags & (PTE_I | PTE_G)) == 0)
                  __syncicache((void *)va, PAGE_SIZE);
  
          tlb_miss_unlock();
          mtx_unlock_spin(&tlbivax_mutex);
  }
  
  /*
   * Remove a page from kernel page table.
   */
  static void
  mmu_booke_kremove(mmu_t mmu, vm_offset_t va)
  {
          pte_t *pte;
  
          CTR2(KTR_PMAP,"%s: s (va = 0x%08x)\n", __func__, va);
  
          KASSERT(((va >= VM_MIN_KERNEL_ADDRESS) &&
              (va <= VM_MAX_KERNEL_ADDRESS)),
              ("mmu_booke_kremove: invalid va"));
  
          pte = pte_find(mmu, kernel_pmap, va);
  
          if (!PTE_ISVALID(pte)) {
          
                  CTR1(KTR_PMAP, "%s: invalid pte", __func__);
  
                  return;
          }
  
          mtx_lock_spin(&tlbivax_mutex);
          tlb_miss_lock();
  
          /* Invalidate entry in TLB0, update PTE. */
          tlb0_flush_entry(va);
          *pte = 0;
  
          tlb_miss_unlock();
          mtx_unlock_spin(&tlbivax_mutex);
  }
  
  /*
   * Initialize pmap associated with process 0.
   */
  static void
  mmu_booke_pinit0(mmu_t mmu, pmap_t pmap)
  {
  
          PMAP_LOCK_INIT(pmap);
          mmu_booke_pinit(mmu, pmap);
          PCPU_SET(curpmap, pmap);
  }
  
  /*
   * Initialize a preallocated and zeroed pmap structure,
   * such as one in a vmspace structure.
   */
  static void
  mmu_booke_pinit(mmu_t mmu, pmap_t pmap)
  {
          int i;
  
          CTR4(KTR_PMAP, "%s: pmap = %p, proc %d '%s'", __func__, pmap,
              curthread->td_proc->p_pid, curthread->td_proc->p_comm);
  
          KASSERT((pmap != kernel_pmap), ("pmap_pinit: initializing kernel_pmap"));
  
          for (i = 0; i < MAXCPU; i++)
                  pmap->pm_tid[i] = TID_NONE;
          CPU_ZERO(&kernel_pmap->pm_active);
          bzero(&pmap->pm_stats, sizeof(pmap->pm_stats));
          bzero(&pmap->pm_pdir, sizeof(pte_t *) * PDIR_NENTRIES);
          TAILQ_INIT(&pmap->pm_ptbl_list);
  }
  
  /*
   * Release any resources held by the given physical map.
   * Called when a pmap initialized by mmu_booke_pinit is being released.
   * Should only be called if the map contains no valid mappings.
   */
  static void
  mmu_booke_release(mmu_t mmu, pmap_t pmap)
  {
  
          KASSERT(pmap->pm_stats.resident_count == 0,
              ("pmap_release: pmap resident count %ld != 0",
              pmap->pm_stats.resident_count));
  }
  
  /*
   * Insert the given physical page at the specified virtual address in the
   * target physical map with the protection requested. If specified the page
   * will be wired down.
   */
  static int
  mmu_booke_enter(mmu_t mmu, pmap_t pmap, vm_offset_t va, vm_page_t m,
      vm_prot_t prot, u_int flags, int8_t psind)
  {
          int error;
  
          rw_wlock(&pvh_global_lock);
          PMAP_LOCK(pmap);
          error = mmu_booke_enter_locked(mmu, pmap, va, m, prot, flags, psind);
          rw_wunlock(&pvh_global_lock);
          PMAP_UNLOCK(pmap);
          return (error);
  }
  
  static int
  mmu_booke_enter_locked(mmu_t mmu, pmap_t pmap, vm_offset_t va, vm_page_t m,
      vm_prot_t prot, u_int pmap_flags, int8_t psind __unused)
  {
          pte_t *pte;
          vm_paddr_t pa;
          uint32_t flags;
          int error, su, sync;
  
          pa = VM_PAGE_TO_PHYS(m);
          su = (pmap == kernel_pmap);
          sync = 0;
  
          //debugf("mmu_booke_enter_locked: s (pmap=0x%08x su=%d tid=%d m=0x%08x va=0x%08x "
          //              "pa=0x%08x prot=0x%08x flags=%#x)\n",
          //              (u_int32_t)pmap, su, pmap->pm_tid,
          //              (u_int32_t)m, va, pa, prot, flags);
  
          if (su) {
                  KASSERT(((va >= virtual_avail) &&
                      (va <= VM_MAX_KERNEL_ADDRESS)),
                      ("mmu_booke_enter_locked: kernel pmap, non kernel va"));
          } else {
                  KASSERT((va <= VM_MAXUSER_ADDRESS),
                      ("mmu_booke_enter_locked: user pmap, non user va"));
          }
          if ((m->oflags & VPO_UNMANAGED) == 0 && !vm_page_xbusied(m))
                  VM_OBJECT_ASSERT_LOCKED(m->object);
  
          PMAP_LOCK_ASSERT(pmap, MA_OWNED);
  
          /*
           * If there is an existing mapping, and the physical address has not
           * changed, must be protection or wiring change.
           */
          if (((pte = pte_find(mmu, pmap, va)) != NULL) &&
              (PTE_ISVALID(pte)) && (PTE_PA(pte) == pa)) {
              
                  /*
                   * Before actually updating pte->flags we calculate and
                   * prepare its new value in a helper var.
                   */
                  flags = *pte;
                  flags &= ~(PTE_UW | PTE_UX | PTE_SW | PTE_SX | PTE_MODIFIED);
  
                  /* Wiring change, just update stats. */
                  if ((pmap_flags & PMAP_ENTER_WIRED) != 0) {
                          if (!PTE_ISWIRED(pte)) {
                                  flags |= PTE_WIRED;
                                  pmap->pm_stats.wired_count++;
                          }
                  } else {
                          if (PTE_ISWIRED(pte)) {
                                  flags &= ~PTE_WIRED;
                                  pmap->pm_stats.wired_count--;
                          }
                  }
  
                  if (prot & VM_PROT_WRITE) {
                          /* Add write permissions. */
                          flags |= PTE_SW;
                          if (!su)
                                  flags |= PTE_UW;
  
                          if ((flags & PTE_MANAGED) != 0)
                                  vm_page_aflag_set(m, PGA_WRITEABLE);
                  } else {
                          /* Handle modified pages, sense modify status. */
  
                          /*
                           * The PTE_MODIFIED flag could be set by underlying
                           * TLB misses since we last read it (above), possibly
                           * other CPUs could update it so we check in the PTE
                           * directly rather than rely on that saved local flags
                           * copy.
                           */
                          if (PTE_ISMODIFIED(pte))
                                  vm_page_dirty(m);
                  }
  
                  if (prot & VM_PROT_EXECUTE) {
                          flags |= PTE_SX;
                          if (!su)
                                  flags |= PTE_UX;
  
                          /*
                           * Check existing flags for execute permissions: if we
                           * are turning execute permissions on, icache should
                           * be flushed.
                           */
                          if ((*pte & (PTE_UX | PTE_SX)) == 0)
                                  sync++;
                  }
  
                  flags &= ~PTE_REFERENCED;
  
                  /*
                   * The new flags value is all calculated -- only now actually
                   * update the PTE.
                   */
                  mtx_lock_spin(&tlbivax_mutex);
                  tlb_miss_lock();
  
                  tlb0_flush_entry(va);
                  *pte &= ~PTE_FLAGS_MASK;
                  *pte |= flags;
  
                  tlb_miss_unlock();
                  mtx_unlock_spin(&tlbivax_mutex);
  
          } else {
                  /*
                   * If there is an existing mapping, but it's for a different
                   * physical address, pte_enter() will delete the old mapping.
                   */
                  //if ((pte != NULL) && PTE_ISVALID(pte))
                  //      debugf("mmu_booke_enter_locked: replace\n");
                  //else
                  //      debugf("mmu_booke_enter_locked: new\n");
  
                  /* Now set up the flags and install the new mapping. */
                  flags = (PTE_SR | PTE_VALID);
                  flags |= PTE_M;
  
                  if (!su)
                          flags |= PTE_UR;
  
                  if (prot & VM_PROT_WRITE) {
                          flags |= PTE_SW;
                          if (!su)
                                  flags |= PTE_UW;
  
                          if ((m->oflags & VPO_UNMANAGED) == 0)
                                  vm_page_aflag_set(m, PGA_WRITEABLE);
                  }
  
                  if (prot & VM_PROT_EXECUTE) {
                          flags |= PTE_SX;
                          if (!su)
                                  flags |= PTE_UX;
                  }
  
                  /* If its wired update stats. */
                  if ((pmap_flags & PMAP_ENTER_WIRED) != 0)
                          flags |= PTE_WIRED;
  
                  error = pte_enter(mmu, pmap, m, va, flags,
                      (pmap_flags & PMAP_ENTER_NOSLEEP) != 0);
                  if (error != 0)
                          return (KERN_RESOURCE_SHORTAGE);
  
                  if ((flags & PMAP_ENTER_WIRED) != 0)
                          pmap->pm_stats.wired_count++;
  
                  /* Flush the real memory from the instruction cache. */
                  if (prot & VM_PROT_EXECUTE)
                          sync++;
          }
  
          if (sync && (su || pmap == PCPU_GET(curpmap))) {
                  __syncicache((void *)va, PAGE_SIZE);
                  sync = 0;
          }
  
          return (KERN_SUCCESS);
  }
  
  /*
   * 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.
   */
  static void
  mmu_booke_enter_object(mmu_t mmu, pmap_t pmap, vm_offset_t start,
      vm_offset_t end, vm_page_t m_start, vm_prot_t prot)
  {
          vm_page_t m;
          vm_pindex_t diff, psize;
  
          VM_OBJECT_ASSERT_LOCKED(m_start->object);
  
          psize = atop(end - start);
          m = m_start;
          rw_wlock(&pvh_global_lock);
          PMAP_LOCK(pmap);
          while (m != NULL && (diff = m->pindex - m_start->pindex) < psize) {
                  mmu_booke_enter_locked(mmu, pmap, start + ptoa(diff), m,
                      prot & (VM_PROT_READ | VM_PROT_EXECUTE),
                      PMAP_ENTER_NOSLEEP, 0);
                  m = TAILQ_NEXT(m, listq);
          }
          rw_wunlock(&pvh_global_lock);
          PMAP_UNLOCK(pmap);
  }
  
  static void
  mmu_booke_enter_quick(mmu_t mmu, pmap_t pmap, vm_offset_t va, vm_page_t m,
      vm_prot_t prot)
  {
  
          rw_wlock(&pvh_global_lock);
          PMAP_LOCK(pmap);
          mmu_booke_enter_locked(mmu, pmap, va, m,
              prot & (VM_PROT_READ | VM_PROT_EXECUTE), PMAP_ENTER_NOSLEEP,
              0);
          rw_wunlock(&pvh_global_lock);
          PMAP_UNLOCK(pmap);
  }
  
  /*
   * 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.
   */
  static void
  mmu_booke_remove(mmu_t mmu, pmap_t pmap, vm_offset_t va, vm_offset_t endva)
  {
          pte_t *pte;
          uint8_t hold_flag;
  
          int su = (pmap == kernel_pmap);
  
          //debugf("mmu_booke_remove: s (su = %d pmap=0x%08x tid=%d va=0x%08x endva=0x%08x)\n",
          //              su, (u_int32_t)pmap, pmap->pm_tid, va, endva);
  
          if (su) {
                  KASSERT(((va >= virtual_avail) &&
                      (va <= VM_MAX_KERNEL_ADDRESS)),
                      ("mmu_booke_remove: kernel pmap, non kernel va"));
          } else {
                  KASSERT((va <= VM_MAXUSER_ADDRESS),
                      ("mmu_booke_remove: user pmap, non user va"));
          }
  
          if (PMAP_REMOVE_DONE(pmap)) {
                  //debugf("mmu_booke_remove: e (empty)\n");
                  return;
          }
  
          hold_flag = PTBL_HOLD_FLAG(pmap);
          //debugf("mmu_booke_remove: hold_flag = %d\n", hold_flag);
  
          rw_wlock(&pvh_global_lock);
          PMAP_LOCK(pmap);
          for (; va < endva; va += PAGE_SIZE) {
                  pte = pte_find(mmu, pmap, va);
                  if ((pte != NULL) && PTE_ISVALID(pte))
                          pte_remove(mmu, pmap, va, hold_flag);
          }
          PMAP_UNLOCK(pmap);
          rw_wunlock(&pvh_global_lock);
  
          //debugf("mmu_booke_remove: e\n");
  }
  
  /*
   * Remove physical page from all pmaps in which it resides.
   */
  static void
  mmu_booke_remove_all(mmu_t mmu, vm_page_t m)
  {
          pv_entry_t pv, pvn;
          uint8_t hold_flag;
  
          rw_wlock(&pvh_global_lock);
          for (pv = TAILQ_FIRST(&m->md.pv_list); pv != NULL; pv = pvn) {
                  pvn = TAILQ_NEXT(pv, pv_link);
  
                  PMAP_LOCK(pv->pv_pmap);
                  hold_flag = PTBL_HOLD_FLAG(pv->pv_pmap);
                  pte_remove(mmu, pv->pv_pmap, pv->pv_va, hold_flag);
                  PMAP_UNLOCK(pv->pv_pmap);
          }
          vm_page_aflag_clear(m, PGA_WRITEABLE);
          rw_wunlock(&pvh_global_lock);
  }
  
  /*
   * Map a range of physical addresses into kernel virtual address space.
   */
  static vm_offset_t
  mmu_booke_map(mmu_t mmu, vm_offset_t *virt, vm_paddr_t pa_start,
      vm_paddr_t pa_end, int prot)
  {
          vm_offset_t sva = *virt;
          vm_offset_t va = sva;
  
          //debugf("mmu_booke_map: s (sva = 0x%08x pa_start = 0x%08x pa_end = 0x%08x)\n",
          //              sva, pa_start, pa_end);
  
          while (pa_start < pa_end) {
                  mmu_booke_kenter(mmu, va, pa_start);
                  va += PAGE_SIZE;
                  pa_start += PAGE_SIZE;
          }
          *virt = va;
  
          //debugf("mmu_booke_map: e (va = 0x%08x)\n", va);
          return (sva);
  }
  
  /*
   * The pmap must be activated before it's address space can be accessed in any
   * way.
   */
  static void
  mmu_booke_activate(mmu_t mmu, struct thread *td)
  {
          pmap_t pmap;
          u_int cpuid;
  
          pmap = &td->td_proc->p_vmspace->vm_pmap;
  
          CTR5(KTR_PMAP, "%s: s (td = %p, proc = '%s', id = %d, pmap = 0x%08x)",
              __func__, td, td->td_proc->p_comm, td->td_proc->p_pid, pmap);
  
          KASSERT((pmap != kernel_pmap), ("mmu_booke_activate: kernel_pmap!"));
  
          sched_pin();
  
          cpuid = PCPU_GET(cpuid);
          CPU_SET_ATOMIC(cpuid, &pmap->pm_active);
          PCPU_SET(curpmap, pmap);
          
          if (pmap->pm_tid[cpuid] == TID_NONE)
                  tid_alloc(pmap);
  
          /* Load PID0 register with pmap tid value. */
          mtspr(SPR_PID0, pmap->pm_tid[cpuid]);
          __asm __volatile("isync");
  
          mtspr(SPR_DBCR0, td->td_pcb->pcb_cpu.booke.dbcr0);
  
          sched_unpin();
  
          CTR3(KTR_PMAP, "%s: e (tid = %d for '%s')", __func__,
              pmap->pm_tid[PCPU_GET(cpuid)], td->td_proc->p_comm);
  }
  
  /*
   * Deactivate the specified process's address space.
   */
  static void
  mmu_booke_deactivate(mmu_t mmu, struct thread *td)
  {
          pmap_t pmap;
  
          pmap = &td->td_proc->p_vmspace->vm_pmap;
          
          CTR5(KTR_PMAP, "%s: td=%p, proc = '%s', id = %d, pmap = 0x%08x",
              __func__, td, td->td_proc->p_comm, td->td_proc->p_pid, pmap);
  
          td->td_pcb->pcb_cpu.booke.dbcr0 = mfspr(SPR_DBCR0);
  
          CPU_CLR_ATOMIC(PCPU_GET(cpuid), &pmap->pm_active);
          PCPU_SET(curpmap, NULL);
  }
  
  /*
   * 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.
   */
  static void
  mmu_booke_copy(mmu_t mmu, pmap_t dst_pmap, pmap_t src_pmap,
      vm_offset_t dst_addr, vm_size_t len, vm_offset_t src_addr)
  {
  
  }
  
  /*
   * Set the physical protection on the specified range of this map as requested.
   */
  static void
  mmu_booke_protect(mmu_t mmu, pmap_t pmap, vm_offset_t sva, vm_offset_t eva,
      vm_prot_t prot)
  {
          vm_offset_t va;
          vm_page_t m;
          pte_t *pte;
  
          if ((prot & VM_PROT_READ) == VM_PROT_NONE) {
                  mmu_booke_remove(mmu, pmap, sva, eva);
                  return;
          }
  
          if (prot & VM_PROT_WRITE)
                  return;
  
          PMAP_LOCK(pmap);
          for (va = sva; va < eva; va += PAGE_SIZE) {
                  if ((pte = pte_find(mmu, pmap, va)) != NULL) {
                          if (PTE_ISVALID(pte)) {
                                  m = PHYS_TO_VM_PAGE(PTE_PA(pte));
  
                                  mtx_lock_spin(&tlbivax_mutex);
                                  tlb_miss_lock();
  
                                  /* Handle modified pages. */
                                  if (PTE_ISMODIFIED(pte) && PTE_ISMANAGED(pte))
                                          vm_page_dirty(m);
  
                                  tlb0_flush_entry(va);
                                  *pte &= ~(PTE_UW | PTE_SW | PTE_MODIFIED);
  
                                  tlb_miss_unlock();
                                  mtx_unlock_spin(&tlbivax_mutex);
                          }
                  }
          }
          PMAP_UNLOCK(pmap);
  }
  
  /*
   * Clear the write and modified bits in each of the given page's mappings.
   */
  static void
  mmu_booke_remove_write(mmu_t mmu, vm_page_t m)
  {
          pv_entry_t pv;
          pte_t *pte;
  
          KASSERT((m->oflags & VPO_UNMANAGED) == 0,
              ("mmu_booke_remove_write: page %p is not managed", m));
  
          /*
           * If the page is not exclusive busied, then PGA_WRITEABLE cannot be
           * set by another thread while the object is locked.  Thus,
           * if PGA_WRITEABLE is clear, no page table entries need updating.
           */
          VM_OBJECT_ASSERT_WLOCKED(m->object);
          if (!vm_page_xbusied(m) && (m->aflags & PGA_WRITEABLE) == 0)
                  return;
          rw_wlock(&pvh_global_lock);
          TAILQ_FOREACH(pv, &m->md.pv_list, pv_link) {
                  PMAP_LOCK(pv->pv_pmap);
                  if ((pte = pte_find(mmu, pv->pv_pmap, pv->pv_va)) != NULL) {
                          if (PTE_ISVALID(pte)) {
                                  m = PHYS_TO_VM_PAGE(PTE_PA(pte));
  
                                  mtx_lock_spin(&tlbivax_mutex);
                                  tlb_miss_lock();
  
                                  /* Handle modified pages. */
                                  if (PTE_ISMODIFIED(pte))
                                          vm_page_dirty(m);
  
                                  /* Flush mapping from TLB0. */
                                  *pte &= ~(PTE_UW | PTE_SW | PTE_MODIFIED);
  
                                  tlb_miss_unlock();
                                  mtx_unlock_spin(&tlbivax_mutex);
                          }
                  }
                  PMAP_UNLOCK(pv->pv_pmap);
          }
          vm_page_aflag_clear(m, PGA_WRITEABLE);
          rw_wunlock(&pvh_global_lock);
  }
  
  static void
  mmu_booke_sync_icache(mmu_t mmu, pmap_t pm, vm_offset_t va, vm_size_t sz)
  {
          pte_t *pte;
          pmap_t pmap;
          vm_page_t m;
          vm_offset_t addr;
          vm_paddr_t pa = 0;
          int active, valid;
   
          va = trunc_page(va);
          sz = round_page(sz);
  
          rw_wlock(&pvh_global_lock);
          pmap = PCPU_GET(curpmap);
          active = (pm == kernel_pmap || pm == pmap) ? 1 : 0;
          while (sz > 0) {
                  PMAP_LOCK(pm);
                  pte = pte_find(mmu, pm, va);
                  valid = (pte != NULL && PTE_ISVALID(pte)) ? 1 : 0;
                  if (valid)
                          pa = PTE_PA(pte);
                  PMAP_UNLOCK(pm);
                  if (valid) {
                          if (!active) {
                                  /* Create a mapping in the active pmap. */
                                  addr = 0;
                                  m = PHYS_TO_VM_PAGE(pa);
                                  PMAP_LOCK(pmap);
                                  pte_enter(mmu, pmap, m, addr,
                                      PTE_SR | PTE_VALID | PTE_UR, FALSE);
                                  __syncicache((void *)addr, PAGE_SIZE);
                                  pte_remove(mmu, pmap, addr, PTBL_UNHOLD);
                                  PMAP_UNLOCK(pmap);
                          } else
                                  __syncicache((void *)va, PAGE_SIZE);
                  }
                  va += PAGE_SIZE;
                  sz -= PAGE_SIZE;
          }
          rw_wunlock(&pvh_global_lock);
  }
  
  /*
   * Atomically extract and hold the physical page with the given
   * pmap and virtual address pair if that mapping permits the given
   * protection.
   */
  static vm_page_t
  mmu_booke_extract_and_hold(mmu_t mmu, pmap_t pmap, vm_offset_t va,
      vm_prot_t prot)
  {
          pte_t *pte;
          vm_page_t m;
          uint32_t pte_wbit;
          vm_paddr_t pa;
          
          m = NULL;
          pa = 0; 
          PMAP_LOCK(pmap);
  retry:
          pte = pte_find(mmu, pmap, va);
          if ((pte != NULL) && PTE_ISVALID(pte)) {
                  if (pmap == kernel_pmap)
                          pte_wbit = PTE_SW;
                  else
                          pte_wbit = PTE_UW;
  
                  if ((*pte & pte_wbit) || ((prot & VM_PROT_WRITE) == 0)) {
                          if (vm_page_pa_tryrelock(pmap, PTE_PA(pte), &pa))
                                  goto retry;
                          m = PHYS_TO_VM_PAGE(PTE_PA(pte));
                          vm_page_hold(m);
                  }
          }
  
          PA_UNLOCK_COND(pa);
          PMAP_UNLOCK(pmap);
          return (m);
  }
  
  /*
   * Initialize a vm_page's machine-dependent fields.
   */
  static void
  mmu_booke_page_init(mmu_t mmu, vm_page_t m)
  {
  
          TAILQ_INIT(&m->md.pv_list);
  }
  
  /*
   * mmu_booke_zero_page_area zeros the specified hardware page by
   * mapping it into virtual memory and using bzero to clear
   * its contents.
   *
   * off and size must reside within a single page.
   */
  static void
  mmu_booke_zero_page_area(mmu_t mmu, vm_page_t m, int off, int size)
  {
          vm_offset_t va;
  
          /* XXX KASSERT off and size are within a single page? */
  
          mtx_lock(&zero_page_mutex);
          va = zero_page_va;
  
          mmu_booke_kenter(mmu, va, VM_PAGE_TO_PHYS(m));
          bzero((caddr_t)va + off, size);
          mmu_booke_kremove(mmu, va);
  
          mtx_unlock(&zero_page_mutex);
  }
  
  /*
   * mmu_booke_zero_page zeros the specified hardware page.
   */
  static void
  mmu_booke_zero_page(mmu_t mmu, vm_page_t m)
  {
          vm_offset_t off, va;
  
          mtx_lock(&zero_page_mutex);
          va = zero_page_va;
  
          mmu_booke_kenter(mmu, va, VM_PAGE_TO_PHYS(m));
          for (off = 0; off < PAGE_SIZE; off += cacheline_size)
                  __asm __volatile("dcbz 0,%0" :: "r"(va + off));
          mmu_booke_kremove(mmu, va);
  
          mtx_unlock(&zero_page_mutex);
  }
  
  /*
   * mmu_booke_copy_page copies the specified (machine independent) page by
   * mapping the page into virtual memory and using memcopy to copy the page,
   * one machine dependent page at a time.
   */
  static void
  mmu_booke_copy_page(mmu_t mmu, vm_page_t sm, vm_page_t dm)
  {
          vm_offset_t sva, dva;
  
          sva = copy_page_src_va;
          dva = copy_page_dst_va;
  
          mtx_lock(&copy_page_mutex);
          mmu_booke_kenter(mmu, sva, VM_PAGE_TO_PHYS(sm));
          mmu_booke_kenter(mmu, dva, VM_PAGE_TO_PHYS(dm));
          memcpy((caddr_t)dva, (caddr_t)sva, PAGE_SIZE);
          mmu_booke_kremove(mmu, dva);
          mmu_booke_kremove(mmu, sva);
          mtx_unlock(&copy_page_mutex);
  }
  
  static inline void
  mmu_booke_copy_pages(mmu_t mmu, vm_page_t *ma, vm_offset_t a_offset,
      vm_page_t *mb, vm_offset_t b_offset, int xfersize)
  {
          void *a_cp, *b_cp;
          vm_offset_t a_pg_offset, b_pg_offset;
          int cnt;
  
          mtx_lock(&copy_page_mutex);
          while (xfersize > 0) {
                  a_pg_offset = a_offset & PAGE_MASK;
                  cnt = min(xfersize, PAGE_SIZE - a_pg_offset);
                  mmu_booke_kenter(mmu, copy_page_src_va,
                      VM_PAGE_TO_PHYS(ma[a_offset >> PAGE_SHIFT]));
                  a_cp = (char *)copy_page_src_va + a_pg_offset;
                  b_pg_offset = b_offset & PAGE_MASK;
                  cnt = min(cnt, PAGE_SIZE - b_pg_offset);
                  mmu_booke_kenter(mmu, copy_page_dst_va,
                      VM_PAGE_TO_PHYS(mb[b_offset >> PAGE_SHIFT]));
                  b_cp = (char *)copy_page_dst_va + b_pg_offset;
                  bcopy(a_cp, b_cp, cnt);
                  mmu_booke_kremove(mmu, copy_page_dst_va);
                  mmu_booke_kremove(mmu, copy_page_src_va);
                  a_offset += cnt;
                  b_offset += cnt;
                  xfersize -= cnt;
          }
          mtx_unlock(&copy_page_mutex);
  }
  
  /*
   * mmu_booke_zero_page_idle zeros the specified hardware page by mapping it
   * into virtual memory and using bzero to clear its contents. This is intended
   * to be called from the vm_pagezero process only and outside of Giant. No
   * lock is required.
   */
  static void
  mmu_booke_zero_page_idle(mmu_t mmu, vm_page_t m)
  {
          vm_offset_t va;
  
          va = zero_page_idle_va;
          mmu_booke_kenter(mmu, va, VM_PAGE_TO_PHYS(m));
          bzero((caddr_t)va, PAGE_SIZE);
          mmu_booke_kremove(mmu, va);
  }
  
  static vm_offset_t
  mmu_booke_quick_enter_page(mmu_t mmu, vm_page_t m)
  {
          vm_paddr_t paddr;
          vm_offset_t qaddr;
          uint32_t flags;
          pte_t *pte;
  
          paddr = VM_PAGE_TO_PHYS(m);
  
          flags = PTE_SR | PTE_SW | PTE_SX | PTE_WIRED | PTE_VALID;
          flags |= tlb_calc_wimg(paddr, pmap_page_get_memattr(m)) << PTE_MAS2_SHIFT;
          flags |= PTE_PS_4KB;
  
          critical_enter();
          qaddr = PCPU_GET(qmap_addr);
  
          pte = pte_find(mmu, kernel_pmap, qaddr);
  
          KASSERT(*pte == 0, ("mmu_booke_quick_enter_page: PTE busy"));
  
          /* 
           * XXX: tlbivax is broadcast to other cores, but qaddr should
           * not be present in other TLBs.  Is there a better instruction
           * sequence to use? Or just forget it & use mmu_booke_kenter()... 
           */
          __asm __volatile("tlbivax 0, %0" :: "r"(qaddr & MAS2_EPN_MASK));
          __asm __volatile("isync; msync");
  
          *pte = PTE_RPN_FROM_PA(paddr) | flags;
  
          /* Flush the real memory from the instruction cache. */
          if ((flags & (PTE_I | PTE_G)) == 0)
                  __syncicache((void *)qaddr, PAGE_SIZE);
  
          return (qaddr);
  }
  
  static void
  mmu_booke_quick_remove_page(mmu_t mmu, vm_offset_t addr)
  {
          pte_t *pte;
  
          pte = pte_find(mmu, kernel_pmap, addr);
  
          KASSERT(PCPU_GET(qmap_addr) == addr,
              ("mmu_booke_quick_remove_page: invalid address"));
          KASSERT(*pte != 0,
              ("mmu_booke_quick_remove_page: PTE not in use"));
  
          *pte = 0;
          critical_exit();
  }
  
  /*
   * Return whether or not the specified physical page was modified
   * in any of physical maps.
   */
  static boolean_t
  mmu_booke_is_modified(mmu_t mmu, vm_page_t m)
  {
          pte_t *pte;
          pv_entry_t pv;
          boolean_t rv;
  
          KASSERT((m->oflags & VPO_UNMANAGED) == 0,
              ("mmu_booke_is_modified: page %p is not managed", m));
          rv = FALSE;
  
          /*
           * If the page is not exclusive busied, then PGA_WRITEABLE cannot be
           * concurrently set while the object is locked.  Thus, if PGA_WRITEABLE
           * is clear, no PTEs can be modified.
           */
          VM_OBJECT_ASSERT_WLOCKED(m->object);
          if (!vm_page_xbusied(m) && (m->aflags & PGA_WRITEABLE) == 0)
                  return (rv);
          rw_wlock(&pvh_global_lock);
          TAILQ_FOREACH(pv, &m->md.pv_list, pv_link) {
                  PMAP_LOCK(pv->pv_pmap);
                  if ((pte = pte_find(mmu, pv->pv_pmap, pv->pv_va)) != NULL &&
                      PTE_ISVALID(pte)) {
                          if (PTE_ISMODIFIED(pte))
                                  rv = TRUE;
                  }
                  PMAP_UNLOCK(pv->pv_pmap);
                  if (rv)
                          break;
          }
          rw_wunlock(&pvh_global_lock);
          return (rv);
  }
  
  /*
   * Return whether or not the specified virtual address is eligible
   * for prefault.
   */
  static boolean_t
  mmu_booke_is_prefaultable(mmu_t mmu, pmap_t pmap, vm_offset_t addr)
  {
  
          return (FALSE);
  }
  
  /*
   * Return whether or not the specified physical page was referenced
   * in any physical maps.
   */
  static boolean_t
  mmu_booke_is_referenced(mmu_t mmu, vm_page_t m)
  {
          pte_t *pte;
          pv_entry_t pv;
          boolean_t rv;
  
          KASSERT((m->oflags & VPO_UNMANAGED) == 0,
              ("mmu_booke_is_referenced: page %p is not managed", m));
          rv = FALSE;
          rw_wlock(&pvh_global_lock);
          TAILQ_FOREACH(pv, &m->md.pv_list, pv_link) {
                  PMAP_LOCK(pv->pv_pmap);
                  if ((pte = pte_find(mmu, pv->pv_pmap, pv->pv_va)) != NULL &&
                      PTE_ISVALID(pte)) {
                          if (PTE_ISREFERENCED(pte))
                                  rv = TRUE;
                  }
                  PMAP_UNLOCK(pv->pv_pmap);
                  if (rv)
                          break;
          }
          rw_wunlock(&pvh_global_lock);
          return (rv);
  }
  
  /*
   * Clear the modify bits on the specified physical page.
   */
  static void
  mmu_booke_clear_modify(mmu_t mmu, vm_page_t m)
  {
          pte_t *pte;
          pv_entry_t pv;
  
          KASSERT((m->oflags & VPO_UNMANAGED) == 0,
              ("mmu_booke_clear_modify: page %p is not managed", m));
          VM_OBJECT_ASSERT_WLOCKED(m->object);
          KASSERT(!vm_page_xbusied(m),
              ("mmu_booke_clear_modify: page %p is exclusive busied", m));
  
          /*
           * If the page is not PG_AWRITEABLE, then no PTEs can be modified.
           * If the object containing the page is locked and the page is not
           * exclusive busied, then PG_AWRITEABLE cannot be concurrently set.
           */
          if ((m->aflags & PGA_WRITEABLE) == 0)
                  return;
          rw_wlock(&pvh_global_lock);
          TAILQ_FOREACH(pv, &m->md.pv_list, pv_link) {
                  PMAP_LOCK(pv->pv_pmap);
                  if ((pte = pte_find(mmu, pv->pv_pmap, pv->pv_va)) != NULL &&
                      PTE_ISVALID(pte)) {
                          mtx_lock_spin(&tlbivax_mutex);
                          tlb_miss_lock();
                          
                          if (*pte & (PTE_SW | PTE_UW | PTE_MODIFIED)) {
                                  tlb0_flush_entry(pv->pv_va);
                                  *pte &= ~(PTE_SW | PTE_UW | PTE_MODIFIED |
                                      PTE_REFERENCED);
                          }
  
                          tlb_miss_unlock();
                          mtx_unlock_spin(&tlbivax_mutex);
                  }
                  PMAP_UNLOCK(pv->pv_pmap);
          }
          rw_wunlock(&pvh_global_lock);
  }
  
  /*
   * Return a count of reference bits for a page, clearing those bits.
   * It is not necessary for every reference bit to be cleared, but it
   * is necessary that 0 only be returned when there are truly no
   * reference bits set.
   *
   * XXX: The exact number of bits to check and clear is a matter that
   * should be tested and standardized at some point in the future for
   * optimal aging of shared pages.
   */
  static int
  mmu_booke_ts_referenced(mmu_t mmu, vm_page_t m)
  {
          pte_t *pte;
          pv_entry_t pv;
          int count;
  
          KASSERT((m->oflags & VPO_UNMANAGED) == 0,
              ("mmu_booke_ts_referenced: page %p is not managed", m));
          count = 0;
          rw_wlock(&pvh_global_lock);
          TAILQ_FOREACH(pv, &m->md.pv_list, pv_link) {
                  PMAP_LOCK(pv->pv_pmap);
                  if ((pte = pte_find(mmu, pv->pv_pmap, pv->pv_va)) != NULL &&
                      PTE_ISVALID(pte)) {
                          if (PTE_ISREFERENCED(pte)) {
                                  mtx_lock_spin(&tlbivax_mutex);
                                  tlb_miss_lock();
  
                                  tlb0_flush_entry(pv->pv_va);
                                  *pte &= ~PTE_REFERENCED;
  
                                  tlb_miss_unlock();
                                  mtx_unlock_spin(&tlbivax_mutex);
  
                                  if (++count > 4) {
                                          PMAP_UNLOCK(pv->pv_pmap);
                                          break;
                                  }
                          }
                  }
                  PMAP_UNLOCK(pv->pv_pmap);
          }
          rw_wunlock(&pvh_global_lock);
          return (count);
  }
  
  /*
   * Clear the wired attribute from the mappings for the specified range of
   * addresses in the given pmap.  Every valid mapping within that range must
   * have the wired attribute set.  In contrast, invalid mappings cannot have
   * the wired attribute set, so they are ignored.
   *
   * The wired attribute of the page table entry is not a hardware feature, so
   * there is no need to invalidate any TLB entries.
   */
  static void
  mmu_booke_unwire(mmu_t mmu, pmap_t pmap, vm_offset_t sva, vm_offset_t eva)
  {
          vm_offset_t va;
          pte_t *pte;
  
          PMAP_LOCK(pmap);
          for (va = sva; va < eva; va += PAGE_SIZE) {
                  if ((pte = pte_find(mmu, pmap, va)) != NULL &&
                      PTE_ISVALID(pte)) {
                          if (!PTE_ISWIRED(pte))
                                  panic("mmu_booke_unwire: pte %p isn't wired",
                                      pte);
                          *pte &= ~PTE_WIRED;
                          pmap->pm_stats.wired_count--;
                  }
          }
          PMAP_UNLOCK(pmap);
  
  }
  
  /*
   * Return true if the pmap's pv is one of the first 16 pvs linked to from this
   * page.  This count may be changed upwards or downwards in the future; it is
   * only necessary that true be returned for a small subset of pmaps for proper
   * page aging.
   */
  static boolean_t
  mmu_booke_page_exists_quick(mmu_t mmu, pmap_t pmap, vm_page_t m)
  {
          pv_entry_t pv;
          int loops;
          boolean_t rv;
  
          KASSERT((m->oflags & VPO_UNMANAGED) == 0,
              ("mmu_booke_page_exists_quick: page %p is not managed", m));
          loops = 0;
          rv = FALSE;
          rw_wlock(&pvh_global_lock);
          TAILQ_FOREACH(pv, &m->md.pv_list, pv_link) {
                  if (pv->pv_pmap == pmap) {
                          rv = TRUE;
                          break;
                  }
                  if (++loops >= 16)
                          break;
          }
          rw_wunlock(&pvh_global_lock);
          return (rv);
  }
  
  /*
   * Return the number of managed mappings to the given physical page that are
   * wired.
   */
  static int
  mmu_booke_page_wired_mappings(mmu_t mmu, vm_page_t m)
  {
          pv_entry_t pv;
          pte_t *pte;
          int count = 0;
  
          if ((m->oflags & VPO_UNMANAGED) != 0)
                  return (count);
          rw_wlock(&pvh_global_lock);
          TAILQ_FOREACH(pv, &m->md.pv_list, pv_link) {
                  PMAP_LOCK(pv->pv_pmap);
                  if ((pte = pte_find(mmu, pv->pv_pmap, pv->pv_va)) != NULL)
                          if (PTE_ISVALID(pte) && PTE_ISWIRED(pte))
                                  count++;
                  PMAP_UNLOCK(pv->pv_pmap);
          }
          rw_wunlock(&pvh_global_lock);
          return (count);
  }
  
  static int
  mmu_booke_dev_direct_mapped(mmu_t mmu, vm_paddr_t pa, vm_size_t size)
  {
          int i;
          vm_offset_t va;
  
          /*
           * This currently does not work for entries that
           * overlap TLB1 entries.
           */
          for (i = 0; i < TLB1_ENTRIES; i ++) {
                  if (tlb1_iomapped(i, pa, size, &va) == 0)
                          return (0);
          }
  
          return (EFAULT);
  }
  
  void
  mmu_booke_dumpsys_map(mmu_t mmu, vm_paddr_t pa, size_t sz, void **va)
  {
          vm_paddr_t ppa;
          vm_offset_t ofs;
          vm_size_t gran;
  
          /* Minidumps are based on virtual memory addresses. */
          if (do_minidump) {
                  *va = (void *)(vm_offset_t)pa;
                  return;
          }
  
          /* Raw physical memory dumps don't have a virtual address. */
          /* We always map a 256MB page at 256M. */
          gran = 256 * 1024 * 1024;
          ppa = rounddown2(pa, gran);
          ofs = pa - ppa;
          *va = (void *)gran;
          tlb1_set_entry((vm_offset_t)va, ppa, gran, _TLB_ENTRY_IO);
  
          if (sz > (gran - ofs))
                  tlb1_set_entry((vm_offset_t)(va + gran), ppa + gran, gran,
                      _TLB_ENTRY_IO);
  }
  
  void
  mmu_booke_dumpsys_unmap(mmu_t mmu, vm_paddr_t pa, size_t sz, void *va)
  {
          vm_paddr_t ppa;
          vm_offset_t ofs;
          vm_size_t gran;
          tlb_entry_t e;
          int i;
  
          /* Minidumps are based on virtual memory addresses. */
          /* Nothing to do... */
          if (do_minidump)
                  return;
  
          for (i = 0; i < TLB1_ENTRIES; i++) {
                  tlb1_read_entry(&e, i);
                  if (!(e.mas1 & MAS1_VALID))
                          break;
          }
  
          /* Raw physical memory dumps don't have a virtual address. */
          i--;
          e.mas1 = 0;
          e.mas2 = 0;
          e.mas3 = 0;
          tlb1_write_entry(&e, i);
  
          gran = 256 * 1024 * 1024;
          ppa = rounddown2(pa, gran);
          ofs = pa - ppa;
          if (sz > (gran - ofs)) {
                  i--;
                  e.mas1 = 0;
                  e.mas2 = 0;
                  e.mas3 = 0;
                  tlb1_write_entry(&e, i);
          }
  }
  
  extern struct dump_pa dump_map[PHYS_AVAIL_SZ + 1];
  
  void
  mmu_booke_scan_init(mmu_t mmu)
  {
          vm_offset_t va;
          pte_t *pte;
          int i;
  
          if (!do_minidump) {
                  /* Initialize phys. segments for dumpsys(). */
                  memset(&dump_map, 0, sizeof(dump_map));
                  mem_regions(&physmem_regions, &physmem_regions_sz, &availmem_regions,
                      &availmem_regions_sz);
                  for (i = 0; i < physmem_regions_sz; i++) {
                          dump_map[i].pa_start = physmem_regions[i].mr_start;
                          dump_map[i].pa_size = physmem_regions[i].mr_size;
                  }
                  return;
          }
  
          /* Virtual segments for minidumps: */
          memset(&dump_map, 0, sizeof(dump_map));
  
          /* 1st: kernel .data and .bss. */
          dump_map[0].pa_start = trunc_page((uintptr_t)_etext);
          dump_map[0].pa_size =
              round_page((uintptr_t)_end) - dump_map[0].pa_start;
  
          /* 2nd: msgbuf and tables (see pmap_bootstrap()). */
          dump_map[1].pa_start = data_start;
          dump_map[1].pa_size = data_end - data_start;
  
          /* 3rd: kernel VM. */
          va = dump_map[1].pa_start + dump_map[1].pa_size;
          /* Find start of next chunk (from va). */
          while (va < virtual_end) {
                  /* Don't dump the buffer cache. */
                  if (va >= kmi.buffer_sva && va < kmi.buffer_eva) {
                          va = kmi.buffer_eva;
                          continue;
                  }
                  pte = pte_find(mmu, kernel_pmap, va);
                  if (pte != NULL && PTE_ISVALID(pte))
                          break;
                  va += PAGE_SIZE;
          }
          if (va < virtual_end) {
                  dump_map[2].pa_start = va;
                  va += PAGE_SIZE;
                  /* Find last page in chunk. */
                  while (va < virtual_end) {
                          /* Don't run into the buffer cache. */
                          if (va == kmi.buffer_sva)
                                  break;
                          pte = pte_find(mmu, kernel_pmap, va);
                          if (pte == NULL || !PTE_ISVALID(pte))
                                  break;
                          va += PAGE_SIZE;
                  }
                  dump_map[2].pa_size = va - dump_map[2].pa_start;
          }
  }
  
  /*
   * 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.
   */
  static void *
  mmu_booke_mapdev(mmu_t mmu, vm_paddr_t pa, vm_size_t size)
  {
  
          return (mmu_booke_mapdev_attr(mmu, pa, size, VM_MEMATTR_DEFAULT));
  }
  
  static void *
  mmu_booke_mapdev_attr(mmu_t mmu, vm_paddr_t pa, vm_size_t size, vm_memattr_t ma)
  {
          tlb_entry_t e;
          void *res;
          uintptr_t va, tmpva;
          vm_size_t sz;
          int i;
  
          /*
           * Check if this is premapped in TLB1. Note: this should probably also
           * check whether a sequence of TLB1 entries exist that match the
           * requirement, but now only checks the easy case.
           */
          if (ma == VM_MEMATTR_DEFAULT) {
                  for (i = 0; i < TLB1_ENTRIES; i++) {
                          tlb1_read_entry(&e, i);
                          if (!(e.mas1 & MAS1_VALID))
                                  continue;
                          if (pa >= e.phys &&
                              (pa + size) <= (e.phys + e.size))
                                  return (void *)(e.virt +
                                      (vm_offset_t)(pa - e.phys));
                  }
          }
  
          size = roundup(size, PAGE_SIZE);
  
          /*
           * The device mapping area is between VM_MAXUSER_ADDRESS and
           * VM_MIN_KERNEL_ADDRESS.  This gives 1GB of device addressing.
           */
  #ifdef SPARSE_MAPDEV
          /*
           * With a sparse mapdev, align to the largest starting region.  This
           * could feasibly be optimized for a 'best-fit' alignment, but that
           * calculation could be very costly.
           */
          do {
              tmpva = tlb1_map_base;
              va = roundup(tlb1_map_base, 1 << flsl(size));
          } while (!atomic_cmpset_int(&tlb1_map_base, tmpva, va + size));
  #else
          va = atomic_fetchadd_int(&tlb1_map_base, size);
  #endif
          res = (void *)va;
  
          do {
                  sz = 1 << (ilog2(size) & ~1);
                  if (va % sz != 0) {
                          do {
                                  sz >>= 2;
                          } while (va % sz != 0);
                  }
                  if (bootverbose)
                          printf("Wiring VA=%x to PA=%jx (size=%x)\n",
                              va, (uintmax_t)pa, sz);
                  tlb1_set_entry(va, pa, sz,
                      _TLB_ENTRY_SHARED | tlb_calc_wimg(pa, ma));
                  size -= sz;
                  pa += sz;
                  va += sz;
          } while (size > 0);
  
          return (res);
  }
  
  /*
   * 'Unmap' a range mapped by mmu_booke_mapdev().
   */
  static void
  mmu_booke_unmapdev(mmu_t mmu, vm_offset_t va, vm_size_t size)
  {
  #ifdef SUPPORTS_SHRINKING_TLB1
          vm_offset_t base, offset;
  
          /*
           * Unmap only if this is inside kernel virtual space.
           */
          if ((va >= VM_MIN_KERNEL_ADDRESS) && (va <= VM_MAX_KERNEL_ADDRESS)) {
                  base = trunc_page(va);
                  offset = va & PAGE_MASK;
                  size = roundup(offset + size, PAGE_SIZE);
                  kva_free(base, size);
          }
  #endif
  }
  
  /*
   * mmu_booke_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.
   */
  static void
  mmu_booke_object_init_pt(mmu_t mmu, 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,
              ("mmu_booke_object_init_pt: non-device object"));
  }
  
  /*
   * Perform the pmap work for mincore.
   */
  static int
  mmu_booke_mincore(mmu_t mmu, pmap_t pmap, vm_offset_t addr,
      vm_paddr_t *locked_pa)
  {
  
          /* XXX: this should be implemented at some point */
          return (0);
  }
  
  static int
  mmu_booke_change_attr(mmu_t mmu, vm_offset_t addr, vm_size_t sz,
      vm_memattr_t mode)
  {
          vm_offset_t va;
          pte_t *pte;
          int i, j;
          tlb_entry_t e;
  
          /* Check TLB1 mappings */
          for (i = 0; i < TLB1_ENTRIES; i++) {
                  tlb1_read_entry(&e, i);
                  if (!(e.mas1 & MAS1_VALID))
                          continue;
                  if (addr >= e.virt && addr < e.virt + e.size)
                          break;
          }
          if (i < TLB1_ENTRIES) {
                  /* Only allow full mappings to be modified for now. */
                  /* Validate the range. */
                  for (j = i, va = addr; va < addr + sz; va += e.size, j++) {
                          tlb1_read_entry(&e, j);
                          if (va != e.virt || (sz - (va - addr) < e.size))
                                  return (EINVAL);
                  }
                  for (va = addr; va < addr + sz; va += e.size, i++) {
                          tlb1_read_entry(&e, i);
                          e.mas2 &= ~MAS2_WIMGE_MASK;
                          e.mas2 |= tlb_calc_wimg(e.phys, mode);
  
                          /*
                           * Write it out to the TLB.  Should really re-sync with other
                           * cores.
                           */
                          tlb1_write_entry(&e, i);
                  }
                  return (0);
          }
  
          /* Not in TLB1, try through pmap */
          /* First validate the range. */
          for (va = addr; va < addr + sz; va += PAGE_SIZE) {
                  pte = pte_find(mmu, kernel_pmap, va);
                  if (pte == NULL || !PTE_ISVALID(pte))
                          return (EINVAL);
          }
  
          mtx_lock_spin(&tlbivax_mutex);
          tlb_miss_lock();
          for (va = addr; va < addr + sz; va += PAGE_SIZE) {
                  pte = pte_find(mmu, kernel_pmap, va);
                  *pte &= ~(PTE_MAS2_MASK << PTE_MAS2_SHIFT);
                  *pte |= tlb_calc_wimg(PTE_PA(pte), mode << PTE_MAS2_SHIFT);
                  tlb0_flush_entry(va);
          }
          tlb_miss_unlock();
          mtx_unlock_spin(&tlbivax_mutex);
  
          return (pte_vatopa(mmu, kernel_pmap, va));
  }
  
  /**************************************************************************/
  /* TID handling */
  /**************************************************************************/
  
  /*
   * Allocate a TID. If necessary, steal one from someone else.
   * The new TID is flushed from the TLB before returning.
   */
  static tlbtid_t
  tid_alloc(pmap_t pmap)
  {
          tlbtid_t tid;
          int thiscpu;
  
          KASSERT((pmap != kernel_pmap), ("tid_alloc: kernel pmap"));
  
          CTR2(KTR_PMAP, "%s: s (pmap = %p)", __func__, pmap);
  
          thiscpu = PCPU_GET(cpuid);
  
          tid = PCPU_GET(tid_next);
          if (tid > TID_MAX)
                  tid = TID_MIN;
          PCPU_SET(tid_next, tid + 1);
  
          /* If we are stealing TID then clear the relevant pmap's field */
          if (tidbusy[thiscpu][tid] != NULL) {
  
                  CTR2(KTR_PMAP, "%s: warning: stealing tid %d", __func__, tid);
                  
                  tidbusy[thiscpu][tid]->pm_tid[thiscpu] = TID_NONE;
  
                  /* Flush all entries from TLB0 matching this TID. */
                  tid_flush(tid);
          }
  
          tidbusy[thiscpu][tid] = pmap;
          pmap->pm_tid[thiscpu] = tid;
          __asm __volatile("msync; isync");
  
          CTR3(KTR_PMAP, "%s: e (%02d next = %02d)", __func__, tid,
              PCPU_GET(tid_next));
  
          return (tid);
  }
  
  /**************************************************************************/
  /* TLB0 handling */
  /**************************************************************************/
  
  static void
  tlb_print_entry(int i, uint32_t mas1, uint32_t mas2, uint32_t mas3,
      uint32_t mas7)
  {
          int as;
          char desc[3];
          tlbtid_t tid;
          vm_size_t size;
          unsigned int tsize;
  
          desc[2] = '\0';
          if (mas1 & MAS1_VALID)
                  desc[0] = 'V';
          else
                  desc[0] = ' ';
  
          if (mas1 & MAS1_IPROT)
                  desc[1] = 'P';
          else
                  desc[1] = ' ';
  
          as = (mas1 & MAS1_TS_MASK) ? 1 : 0;
          tid = MAS1_GETTID(mas1);
  
          tsize = (mas1 & MAS1_TSIZE_MASK) >> MAS1_TSIZE_SHIFT;
          size = 0;
          if (tsize)
                  size = tsize2size(tsize);
  
          debugf("%3d: (%s) [AS=%d] "
              "sz = 0x%08x tsz = %d tid = %d mas1 = 0x%08x "
              "mas2(va) = 0x%08x mas3(pa) = 0x%08x mas7 = 0x%08x\n",
              i, desc, as, size, tsize, tid, mas1, mas2, mas3, mas7);
  }
  
  /* Convert TLB0 va and way number to tlb0[] table index. */
  static inline unsigned int
  tlb0_tableidx(vm_offset_t va, unsigned int way)
  {
          unsigned int idx;
  
          idx = (way * TLB0_ENTRIES_PER_WAY);
          idx += (va & MAS2_TLB0_ENTRY_IDX_MASK) >> MAS2_TLB0_ENTRY_IDX_SHIFT;
          return (idx);
  }
  
  /*
   * Invalidate TLB0 entry.
   */
  static inline void
  tlb0_flush_entry(vm_offset_t va)
  {
  
          CTR2(KTR_PMAP, "%s: s va=0x%08x", __func__, va);
  
          mtx_assert(&tlbivax_mutex, MA_OWNED);
  
          __asm __volatile("tlbivax 0, %0" :: "r"(va & MAS2_EPN_MASK));
          __asm __volatile("isync; msync");
          __asm __volatile("tlbsync; msync");
  
          CTR1(KTR_PMAP, "%s: e", __func__);
  }
  
  /* Print out contents of the MAS registers for each TLB0 entry */
  void
  tlb0_print_tlbentries(void)
  {
          uint32_t mas0, mas1, mas2, mas3, mas7;
          int entryidx, way, idx;
  
          debugf("TLB0 entries:\n");
          for (way = 0; way < TLB0_WAYS; way ++)
                  for (entryidx = 0; entryidx < TLB0_ENTRIES_PER_WAY; entryidx++) {
  
                          mas0 = MAS0_TLBSEL(0) | MAS0_ESEL(way);
                          mtspr(SPR_MAS0, mas0);
                          __asm __volatile("isync");
  
                          mas2 = entryidx << MAS2_TLB0_ENTRY_IDX_SHIFT;
                          mtspr(SPR_MAS2, mas2);
  
                          __asm __volatile("isync; tlbre");
  
                          mas1 = mfspr(SPR_MAS1);
                          mas2 = mfspr(SPR_MAS2);
                          mas3 = mfspr(SPR_MAS3);
                          mas7 = mfspr(SPR_MAS7);
  
                          idx = tlb0_tableidx(mas2, way);
                          tlb_print_entry(idx, mas1, mas2, mas3, mas7);
                  }
  }
  
  /**************************************************************************/
  /* TLB1 handling */
  /**************************************************************************/
  
  /*
   * TLB1 mapping notes:
   *
   * TLB1[0]      Kernel text and data.
   * TLB1[1-15]   Additional kernel text and data mappings (if required), PCI
   *              windows, other devices mappings.
   */
  
   /*
   * Read an entry from given TLB1 slot.
   */
  void
  tlb1_read_entry(tlb_entry_t *entry, unsigned int slot)
  {
          uint32_t mas0;
  
          KASSERT((entry != NULL), ("%s(): Entry is NULL!", __func__));
  
          mas0 = MAS0_TLBSEL(1) | MAS0_ESEL(slot);
          mtspr(SPR_MAS0, mas0);
          __asm __volatile("isync; tlbre");
  
          entry->mas1 = mfspr(SPR_MAS1);
          entry->mas2 = mfspr(SPR_MAS2);
          entry->mas3 = mfspr(SPR_MAS3);
  
          switch ((mfpvr() >> 16) & 0xFFFF) {
          case FSL_E500v2:
          case FSL_E500mc:
          case FSL_E5500:
                  entry->mas7 = mfspr(SPR_MAS7);
                  break;
          default:
                  entry->mas7 = 0;
                  break;
          }
  
          entry->virt = entry->mas2 & MAS2_EPN_MASK;
          entry->phys = ((vm_paddr_t)(entry->mas7 & MAS7_RPN) << 32) |
              (entry->mas3 & MAS3_RPN);
          entry->size =
              tsize2size((entry->mas1 & MAS1_TSIZE_MASK) >> MAS1_TSIZE_SHIFT);
  }
  
  /*
   * Write given entry to TLB1 hardware.
   * Use 32 bit pa, clear 4 high-order bits of RPN (mas7).
   */
  static void
  tlb1_write_entry(tlb_entry_t *e, unsigned int idx)
  {
          uint32_t mas0;
  
          //debugf("tlb1_write_entry: s\n");
  
          /* Select entry */
          mas0 = MAS0_TLBSEL(1) | MAS0_ESEL(idx);
          //debugf("tlb1_write_entry: mas0 = 0x%08x\n", mas0);
  
          mtspr(SPR_MAS0, mas0);
          __asm __volatile("isync");
          mtspr(SPR_MAS1, e->mas1);
          __asm __volatile("isync");
          mtspr(SPR_MAS2, e->mas2);
          __asm __volatile("isync");
          mtspr(SPR_MAS3, e->mas3);
          __asm __volatile("isync");
          switch ((mfpvr() >> 16) & 0xFFFF) {
          case FSL_E500mc:
          case FSL_E5500:
                  mtspr(SPR_MAS8, 0);
                  __asm __volatile("isync");
                  /* FALLTHROUGH */
          case FSL_E500v2:
                  mtspr(SPR_MAS7, e->mas7);
                  __asm __volatile("isync");
                  break;
          default:
                  break;
          }
  
          __asm __volatile("tlbwe; isync; msync");
  
          //debugf("tlb1_write_entry: e\n");
  }
  
  /*
   * Return the largest uint value log such that 2^log <= num.
   */
  static unsigned int
  ilog2(unsigned int num)
  {
          int lz;
  
          __asm ("cntlzw %0, %1" : "=r" (lz) : "r" (num));
          return (31 - lz);
  }
  
  /*
   * Convert TLB TSIZE value to mapped region size.
   */
  static vm_size_t
  tsize2size(unsigned int tsize)
  {
  
          /*
           * size = 4^tsize KB
           * size = 4^tsize * 2^10 = 2^(2 * tsize - 10)
           */
  
          return ((1 << (2 * tsize)) * 1024);
  }
  
  /*
   * Convert region size (must be power of 4) to TLB TSIZE value.
   */
  static unsigned int
  size2tsize(vm_size_t size)
  {
  
          return (ilog2(size) / 2 - 5);
  }
  
  /*
   * Register permanent kernel mapping in TLB1.
   *
   * Entries are created starting from index 0 (current free entry is
   * kept in tlb1_idx) and are not supposed to be invalidated.
   */
  int
  tlb1_set_entry(vm_offset_t va, vm_paddr_t pa, vm_size_t size,
      uint32_t flags)
  {
          tlb_entry_t e;
          uint32_t ts, tid;
          int tsize, index;
  
          for (index = 0; index < TLB1_ENTRIES; index++) {
                  tlb1_read_entry(&e, index);
                  if ((e.mas1 & MAS1_VALID) == 0)
                          break;
                  /* Check if we're just updating the flags, and update them. */
                  if (e.phys == pa && e.virt == va && e.size == size) {
                          e.mas2 = (va & MAS2_EPN_MASK) | flags;
                          tlb1_write_entry(&e, index);
                          return (0);
                  }
          }
          if (index >= TLB1_ENTRIES) {
                  printf("tlb1_set_entry: TLB1 full!\n");
                  return (-1);
          }
  
          /* Convert size to TSIZE */
          tsize = size2tsize(size);
  
          tid = (TID_KERNEL << MAS1_TID_SHIFT) & MAS1_TID_MASK;
          /* XXX TS is hard coded to 0 for now as we only use single address space */
          ts = (0 << MAS1_TS_SHIFT) & MAS1_TS_MASK;
  
          e.phys = pa;
          e.virt = va;
          e.size = size;
          e.mas1 = MAS1_VALID | MAS1_IPROT | ts | tid;
          e.mas1 |= ((tsize << MAS1_TSIZE_SHIFT) & MAS1_TSIZE_MASK);
          e.mas2 = (va & MAS2_EPN_MASK) | flags;
  
          /* Set supervisor RWX permission bits */
          e.mas3 = (pa & MAS3_RPN) | MAS3_SR | MAS3_SW | MAS3_SX;
          e.mas7 = (pa >> 32) & MAS7_RPN;
  
          tlb1_write_entry(&e, index);
  
          /*
           * XXX in general TLB1 updates should be propagated between CPUs,
           * since current design assumes to have the same TLB1 set-up on all
           * cores.
           */
          return (0);
  }
  
  /*
   * Map in contiguous RAM region into the TLB1 using maximum of
   * KERNEL_REGION_MAX_TLB_ENTRIES entries.
   *
   * If necessary round up last entry size and return total size
   * used by all allocated entries.
   */
  vm_size_t
  tlb1_mapin_region(vm_offset_t va, vm_paddr_t pa, vm_size_t size)
  {
          vm_size_t pgs[KERNEL_REGION_MAX_TLB_ENTRIES];
          vm_size_t mapped, pgsz, base, mask;
          int idx, nents;
  
          /* Round up to the next 1M */
          size = roundup2(size, 1 << 20);
  
          mapped = 0;
          idx = 0;
          base = va;
          pgsz = 64*1024*1024;
          while (mapped < size) {
                  while (mapped < size && idx < KERNEL_REGION_MAX_TLB_ENTRIES) {
                          while (pgsz > (size - mapped))
                                  pgsz >>= 2;
                          pgs[idx++] = pgsz;
                          mapped += pgsz;
                  }
  
                  /* We under-map. Correct for this. */
                  if (mapped < size) {
                          while (pgs[idx - 1] == pgsz) {
                                  idx--;
                                  mapped -= pgsz;
                          }
                          /* XXX We may increase beyond out starting point. */
                          pgsz <<= 2;
                          pgs[idx++] = pgsz;
                          mapped += pgsz;
                  }
          }
  
          nents = idx;
          mask = pgs[0] - 1;
          /* Align address to the boundary */
          if (va & mask) {
                  va = (va + mask) & ~mask;
                  pa = (pa + mask) & ~mask;
          }
  
          for (idx = 0; idx < nents; idx++) {
                  pgsz = pgs[idx];
                  debugf("%u: %llx -> %x, size=%x\n", idx, pa, va, pgsz);
                  tlb1_set_entry(va, pa, pgsz,
                      _TLB_ENTRY_SHARED | _TLB_ENTRY_MEM);
                  pa += pgsz;
                  va += pgsz;
          }
  
          mapped = (va - base);
  #ifdef __powerpc64__
          printf("mapped size 0x%016lx (wasted space 0x%16lx)\n",
  #else
          printf("mapped size 0x%08x (wasted space 0x%08x)\n",
  #endif
              mapped, mapped - size);
          return (mapped);
  }
  
  /*
   * TLB1 initialization routine, to be called after the very first
   * assembler level setup done in locore.S.
   */
  void
  tlb1_init()
  {
          uint32_t mas0, mas1, mas2, mas3, mas7;
          uint32_t tsz;
  
          tlb1_get_tlbconf();
  
          mas0 = MAS0_TLBSEL(1) | MAS0_ESEL(0);
          mtspr(SPR_MAS0, mas0);
          __asm __volatile("isync; tlbre");
  
          mas1 = mfspr(SPR_MAS1);
          mas2 = mfspr(SPR_MAS2);
          mas3 = mfspr(SPR_MAS3);
          mas7 = mfspr(SPR_MAS7);
  
          kernload =  ((vm_paddr_t)(mas7 & MAS7_RPN) << 32) |
              (mas3 & MAS3_RPN);
  
          tsz = (mas1 & MAS1_TSIZE_MASK) >> MAS1_TSIZE_SHIFT;
          kernsize += (tsz > 0) ? tsize2size(tsz) : 0;
  
          /* Setup TLB miss defaults */
          set_mas4_defaults();
  }
  
  vm_offset_t 
  pmap_early_io_map(vm_paddr_t pa, vm_size_t size)
  {
          vm_paddr_t pa_base;
          vm_offset_t va, sz;
          int i;
          tlb_entry_t e;
  
          KASSERT(!pmap_bootstrapped, ("Do not use after PMAP is up!"));
          
          for (i = 0; i < TLB1_ENTRIES; i++) {
                  tlb1_read_entry(&e, i);
                  if (!(e.mas1 & MAS1_VALID))
                          continue;
                  if (pa >= e.phys && (pa + size) <=
                      (e.phys + e.size))
                          return (e.virt + (pa - e.phys));
          }
  
          pa_base = rounddown(pa, PAGE_SIZE);
          size = roundup(size + (pa - pa_base), PAGE_SIZE);
          tlb1_map_base = roundup2(tlb1_map_base, 1 << (ilog2(size) & ~1));
          va = tlb1_map_base + (pa - pa_base);
  
          do {
                  sz = 1 << (ilog2(size) & ~1);
                  tlb1_set_entry(tlb1_map_base, pa_base, sz,
                      _TLB_ENTRY_SHARED | _TLB_ENTRY_IO);
                  size -= sz;
                  pa_base += sz;
                  tlb1_map_base += sz;
          } while (size > 0);
  
          return (va);
  }
  
  /*
   * Setup MAS4 defaults.
   * These values are loaded to MAS0-2 on a TLB miss.
   */
  static void
  set_mas4_defaults(void)
  {
          uint32_t mas4;
  
          /* Defaults: TLB0, PID0, TSIZED=4K */
          mas4 = MAS4_TLBSELD0;
          mas4 |= (TLB_SIZE_4K << MAS4_TSIZED_SHIFT) & MAS4_TSIZED_MASK;
  #ifdef SMP
          mas4 |= MAS4_MD;
  #endif
          mtspr(SPR_MAS4, mas4);
          __asm __volatile("isync");
  }
  
  /*
   * Print out contents of the MAS registers for each TLB1 entry
   */
  void
  tlb1_print_tlbentries(void)
  {
          uint32_t mas0, mas1, mas2, mas3, mas7;
          int i;
  
          debugf("TLB1 entries:\n");
          for (i = 0; i < TLB1_ENTRIES; i++) {
  
                  mas0 = MAS0_TLBSEL(1) | MAS0_ESEL(i);
                  mtspr(SPR_MAS0, mas0);
  
                  __asm __volatile("isync; tlbre");
  
                  mas1 = mfspr(SPR_MAS1);
                  mas2 = mfspr(SPR_MAS2);
                  mas3 = mfspr(SPR_MAS3);
                  mas7 = mfspr(SPR_MAS7);
  
                  tlb_print_entry(i, mas1, mas2, mas3, mas7);
          }
  }
  
  /*
   * Return 0 if the physical IO range is encompassed by one of the
   * the TLB1 entries, otherwise return related error code.
   */
  static int
  tlb1_iomapped(int i, vm_paddr_t pa, vm_size_t size, vm_offset_t *va)
  {
          uint32_t prot;
          vm_paddr_t pa_start;
          vm_paddr_t pa_end;
          unsigned int entry_tsize;
          vm_size_t entry_size;
          tlb_entry_t e;
  
          *va = (vm_offset_t)NULL;
  
          tlb1_read_entry(&e, i);
          /* Skip invalid entries */
          if (!(e.mas1 & MAS1_VALID))
                  return (EINVAL);
  
          /*
           * The entry must be cache-inhibited, guarded, and r/w
           * so it can function as an i/o page
           */
          prot = e.mas2 & (MAS2_I | MAS2_G);
          if (prot != (MAS2_I | MAS2_G))
                  return (EPERM);
  
          prot = e.mas3 & (MAS3_SR | MAS3_SW);
          if (prot != (MAS3_SR | MAS3_SW))
                  return (EPERM);
  
          /* The address should be within the entry range. */
          entry_tsize = (e.mas1 & MAS1_TSIZE_MASK) >> MAS1_TSIZE_SHIFT;
          KASSERT((entry_tsize), ("tlb1_iomapped: invalid entry tsize"));
  
          entry_size = tsize2size(entry_tsize);
          pa_start = (((vm_paddr_t)e.mas7 & MAS7_RPN) << 32) | 
              (e.mas3 & MAS3_RPN);
          pa_end = pa_start + entry_size;
  
          if ((pa < pa_start) || ((pa + size) > pa_end))
                  return (ERANGE);
  
          /* Return virtual address of this mapping. */
          *va = (e.mas2 & MAS2_EPN_MASK) + (pa - pa_start);
          return (0);
  }
  
  /*
   * Invalidate all TLB0 entries which match the given TID. Note this is
   * dedicated for cases when invalidations should NOT be propagated to other
   * CPUs.
   */
  static void
  tid_flush(tlbtid_t tid)
  {
          register_t msr;
          uint32_t mas0, mas1, mas2;
          int entry, way;
  
  
          /* Don't evict kernel translations */
          if (tid == TID_KERNEL)
                  return;
  
          msr = mfmsr();
          __asm __volatile("wrteei 0");
  
          for (way = 0; way < TLB0_WAYS; way++)
                  for (entry = 0; entry < TLB0_ENTRIES_PER_WAY; entry++) {
  
                          mas0 = MAS0_TLBSEL(0) | MAS0_ESEL(way);
                          mtspr(SPR_MAS0, mas0);
                          __asm __volatile("isync");
  
                          mas2 = entry << MAS2_TLB0_ENTRY_IDX_SHIFT;
                          mtspr(SPR_MAS2, mas2);
  
                          __asm __volatile("isync; tlbre");
  
                          mas1 = mfspr(SPR_MAS1);
  
                          if (!(mas1 & MAS1_VALID))
                                  continue;
                          if (((mas1 & MAS1_TID_MASK) >> MAS1_TID_SHIFT) != tid)
                                  continue;
                          mas1 &= ~MAS1_VALID;
                          mtspr(SPR_MAS1, mas1);
                          __asm __volatile("isync; tlbwe; isync; msync");
                  }
          mtmsr(msr);
  }