[apple/xnu.git] / osfmk / ppc / mappings.c

/*
 * Copyright (c) 2000 Apple Computer, Inc. All rights reserved.
 *
 * @APPLE_LICENSE_HEADER_START@
 * 
 * The contents of this file constitute Original Code as defined in and
 * are subject to the Apple Public Source License Version 1.1 (the
 * "License").  You may not use this file except in compliance with the
 * License.  Please obtain a copy of the License at
 * http://www.apple.com/publicsource and read it before using this file.
 * 
 * This Original Code and all software distributed under the License are
 * distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, EITHER
 * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
 * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT.  Please see the
 * License for the specific language governing rights and limitations
 * under the License.
 * 
 * @APPLE_LICENSE_HEADER_END@
 */
/*
 *      This file is used to maintain the virtual to real mappings for a PowerPC machine.
 *      The code herein is primarily used to bridge between the pmap layer and the hardware layer.
 *      Currently, some of the function of this module is contained within pmap.c.  We may want to move
 *      all of this into it (or most anyway) for the sake of performance.  We shall see as we write it.
 *
 *      We also depend upon the structure of the phys_entry control block.  We do put some processor 
 *      specific stuff in there.
 *
 */

#include <cpus.h>
#include <debug.h>
#include <mach_kgdb.h>
#include <mach_vm_debug.h>
#include <db_machine_commands.h>

#include <kern/thread.h>
#include <kern/thread_act.h>
#include <mach/vm_attributes.h>
#include <mach/vm_param.h>
#include <vm/vm_kern.h>
#include <vm/vm_map.h>
#include <vm/vm_page.h>
#include <kern/spl.h>

#include <kern/misc_protos.h>
#include <ppc/misc_protos.h>
#include <ppc/proc_reg.h>

#include <vm/pmap.h>
#include <ppc/pmap.h>
#include <ppc/pmap_internals.h>
#include <ppc/mem.h>

#include <ppc/new_screen.h>
#include <ppc/Firmware.h>
#include <ppc/mappings.h>
#include <ddb/db_output.h>

#include <ppc/POWERMAC/video_console.h>         /* (TEST/DEBUG) */

#define PERFTIMES 0

#if PERFTIMES && DEBUG
#define debugLog2(a, b, c) dbgLog2(a, b, c)
#else
#define debugLog2(a, b, c)
#endif

vm_map_t        mapping_map = VM_MAP_NULL;
#define         MAPPING_MAP_SIZE        33554432        /* 32MB address space */

unsigned int    incrVSID = 0;                                                                   /* VSID increment value */
unsigned int    mappingdeb0 = 0;                                                
unsigned int    mappingdeb1 = 0;                                                
extern unsigned int     hash_table_size;                                                
extern vm_offset_t mem_size;
/*
 *      ppc_prot translates from the mach representation of protections to the PPC version.
 *  We also allow for a direct setting of the protection bits. This extends the mach
 *      concepts to allow the greater control we need for Virtual Machines (VMM).
 *      Calculation of it like this saves a memory reference - and maybe a couple of microseconds.
 *      It eliminates the used of this table.
 *      unsigned char ppc_prot[16] = { 0, 3, 2, 2, 3, 3, 2, 2, 0, 1, 2, 3, 0, 1, 2, 3 };
 */

#define ppc_prot(p) ((0xE4E4AFAC >> (p << 1)) & 3)

/*
 *                      About PPC VSID generation:
 *
 *                      This function is called to generate an address space ID. This space ID must be unique within
 *                      the system.  For the PowerPC, it is used to build the VSID.  We build a VSID in the following
 *                      way:  space ID << 4 | segment.  Since a VSID is 24 bits, and out of that, we reserve the last
 *                      4, so, we can have 2^20 (2M) unique IDs.  Each pmap has a unique space ID, so we should be able
 *                      to have 2M pmaps at a time, which we couldn't, we'd run out of memory way before then.  The 
 *                      problem is that only a certain number of pmaps are kept in a free list and if that is full,
 *                      they are release.  This causes us to lose track of what space IDs are free to be reused.
 *                      We can do 4 things: 1) not worry about it, 2) keep all free pmaps, 3) rebuild all mappings
 *                      when the space ID wraps, or 4) scan the list of pmaps and find a free one.
 *
 *                      Yet another consideration is the hardware use of the VSID.  It is used as part of the hash
 *                      calculation for virtual address lookup.  An improperly chosen value could potentially cause
 *                      too many hashes to hit the same bucket, causing PTEG overflows.  The actual hash function
 *                      is (page index XOR vsid) mod number of ptegs. For a 32MB machine, using the suggested
 *                      hash table size, there are 2^12 (8192) PTEGs.  Remember, though, that the bottom 4 bits
 *                      are reserved for the segment number, which means that we really have 2^(12-4) 512 space IDs
 *                      before we start hashing to the same buckets with the same vaddrs. Also, within a space ID,
 *                      every 8192 pages (32MB) within a segment will hash to the same bucket.  That's 8 collisions
 *                      per segment.  So, a scan of every page for 256MB would fill 32 PTEGs completely, but
 *                      with no overflow.  I don't think that this is a problem.
 *
 *                      There may be a problem with the space ID, though. A new space ID is generate (mainly) 
 *                      whenever there is a fork.  There shouldn't really be any problem because (for a 32MB
 *                      machine) we can have 512 pmaps and still not have hash collisions for the same address.
 *                      The potential problem, though, is if we get long-term pmaps that have space IDs that are
 *                      the same modulo 512.  We can reduce this problem by having the segment number be bits
 *                      0-3 of the space ID rather than 20-23.  Doing this means that, in effect, corresponding
 *                      vaddrs in different segments hash to the same PTEG. While this is somewhat of a problem,
 *                      I don't think that it is as signifigant as the other, so, I'll make the space ID
 *                      with segment first.
 *
 *                      The final, and biggest problem is the wrap, which will happen every 2^20 space IDs.
 *                      While this is a problem that should only happen in periods counted in weeks, it can and
 *                      will happen.  This is assuming a monotonically increasing space ID. If we were to search
 *                      for an inactive space ID, there could not be a wrap until there was 2^20 concurrent space IDs.
 *                      That's pretty unlikely to happen.  There couldn't be enough storage to support a million tasks.
 *
 *                      So, what we do is to keep all active pmaps in a chain (anchored from kernel_pmap and
 *                      locked by free_pmap_lock) that is sorted in VSID sequence order.
 *
 *                      Whenever we need a VSID, we walk the list looking for the next in the sequence from
 *                      the last that was freed.  The we allocate that.
 *
 *                      NOTE: We must be called with interruptions off and free_pmap_lock held.
 *
 */

/*
 *              mapping_init();
 *                      Do anything that needs to be done before the mapping system can be used.
 *                      Hash table must be initialized before we call this.
 *
 *                      Calculate the SID increment.  Currently we use size^(1/2) + size^(1/4) + 1;
 */

void mapping_init(void) {

        unsigned int tmp;
        
        __asm__ volatile("cntlzw %0, %1" : "=r" (tmp) : "r" (hash_table_size)); /* Get number of leading 0s */

        incrVSID = 1 << ((32 - tmp + 1) >> 1);                                          /* Get ceiling of sqrt of table size */
        incrVSID |= 1 << ((32 - tmp + 1) >> 2);                                         /* Get ceiling of quadroot of table size */
        incrVSID |= 1;                                                                                          /* Set bit and add 1 */
        return;

}


/*
 *              mapping_remove(pmap_t pmap, vm_offset_t va);
 *                      Given a pmap and virtual address, this routine finds the mapping and removes it from
 *                      both its PTEG hash list and the physical entry list.  The mapping block will be added to
 *                      the free list.  If the free list threshold is reached, garbage collection will happen.
 *                      We also kick back a return code to say whether or not we had one to remove.
 *
 *                      We have a strict ordering here:  the mapping must be removed from the PTEG hash list before
 *                      it can be removed from the physical entry list.  This allows us to get by with only the PTEG
 *                      hash lock at page fault time. The physical entry lock must be held while we remove the mapping 
 *                      from both lists. The PTEG lock is one of the lowest level locks.  No PTE fault, interruptions,
 *                      losing control, getting other locks, etc., are allowed when you hold it. You do, and you die.
 *                      It's just that simple!
 *
 *                      When the phys_entry lock is held, the mappings chained to that one are guaranteed to stay around.
 *                      However, a mapping's order on the PTEG hash chain is not.  The interrupt handler uses the PTEG
 *                      lock to control the hash cahin and may move the position of the mapping for MRU calculations.
 *
 *                      Note that mappings do not need to point to a physical entry. When they don't, it indicates 
 *                      the mapping is outside of physical memory and usually refers to a memory mapped device of
 *                      some sort.  Naturally, we can't lock what we don't have, so the phys entry lock and unlock
 *                      routines return normally, but don't do anything.
 */

boolean_t mapping_remove(pmap_t pmap, vm_offset_t va) {                 /* Remove a single mapping for this VADDR 
                                                                                                                                   Returns TRUE if a mapping was found to remove */

        mapping         *mp, *mpv;
        register blokmap *blm;
        spl_t           s;
        unsigned int *useadd, *useaddr;
        int i;
        
        debugLog2(1, va, pmap->space);                                                          /* start mapping_remove */

        s=splhigh();                                                                                            /* Don't bother me */
        
        mp = hw_lock_phys_vir(pmap->space, va);                                         /* Lock the physical entry for this mapping */

        if(!mp) {                                                                                                       /* Did we find one? */
                splx(s);                                                                                        /* Allow 'rupts now */
                if(mp = (mapping *)hw_rem_blk(pmap, va, va)) {                  /* No normal pages, try to remove an odd-sized one */
                        
                        if((unsigned int)mp & 1) {                                                      /* Make sure we don't unmap a permanent one */
                                blm = (blokmap *)hw_cpv((mapping *)((unsigned int)mp & 0xFFFFFFFC));            /* Get virtual address */
                                panic("mapping_remove: attempt to unmap a permanent mapping - pmap = %08X, va = %08X, mapping = %08X\n",
                                        pmap, va, blm);
                        }
                        while ((unsigned int)mp & 2)
                                mp = (mapping *)hw_rem_blk(pmap, va, va);
#if 0
                        blm = (blokmap *)hw_cpv(mp);                                            /* (TEST/DEBUG) */
                        kprintf("mapping_remove: removed block map - bm=%08X; start=%08X; end=%08X; PTEr=%08X\n",       /* (TEST/DEBUG) */
                         blm, blm->start, blm->end, blm->PTEr);
#endif
                        mapping_free(hw_cpv(mp));                                                       /* Release it */
                        debugLog2(2, 1, 0);                                                                     /* End mapping_remove */
                        return TRUE;                                                                            /* Tell them we did it */
                }
                debugLog2(2, 0, 0);                                                                             /* end mapping_remove */
                return FALSE;                                                                                   /* Didn't find any, return FALSE... */
        }
        if((unsigned int)mp&1) {                                                                        /* Did we timeout? */
                panic("mapping_remove: timeout locking physical entry\n");      /* Yeah, scream about it! */
                splx(s);                                                                                                /* Restore the interrupt level */
                return FALSE;                                                                                   /* Bad hair day, return FALSE... */
        }
        
        mpv = hw_cpv(mp);                                                                                       /* Get virtual address of mapping */
#if DEBUG
        if(hw_atomic_sub(&mpv->pmap->stats.resident_count, 1) < 0) panic("pmap resident count went negative\n");
#else
        (void)hw_atomic_sub(&mpv->pmap->stats.resident_count, 1);       /* Decrement the resident page count */
#endif
        useadd = (unsigned int *)&pmap->pmapUsage[(va >> pmapUsageShft) & pmapUsageMask];       /* Point to slot to bump */
        useaddr = (unsigned int *)((unsigned int)useadd & -4);          /* Round down to word */
        (void)hw_atomic_sub(useaddr, (useaddr == useadd) ? 0x00010000 : 1);     /* Increment the even or odd slot */

#if 0
        for(i = 0; i < (pmapUsageMask + 1); i++) {                                      /* (TEST/DEBUG) */
                if((mpv->pmap->pmapUsage[i]) > 8192) {                                  /* (TEST/DEBUG) */
                        panic("mapping_remove: pmapUsage slot for %08X has invalid count (%d) for pmap %08X\n",
                                i * pmapUsageSize, mpv->pmap->pmapUsage[i], mpv->pmap);
                }
        }
#endif
        
        hw_rem_map(mp);                                                                                         /* Remove the corresponding mapping */
        
        if(mpv->physent)hw_unlock_bit((unsigned int *)&mpv->physent->phys_link, PHYS_LOCK);     /* Unlock physical entry associated with mapping */
        
        splx(s);                                                                                                        /* Was there something you needed? */
                
        mapping_free(mpv);                                                                                      /* Add mapping to the free list */
        debugLog2(2, 1, 0);                                                                                     /* end mapping_remove */
        return TRUE;                                                                                            /* Tell them we did it */
}

/*
 *              mapping_purge_pmap(struct phys_entry *pp, pmap_t pmap) - release all mappings for this physent for the specified map
 *
 *              This guy releases any mappings that exist for a physical page on a specified map.
 *              We get the lock on the phys_entry, and hold it through out this whole routine.
 *              That way, no one can change the queue out from underneath us.  We keep fetching
 *              the physents mapping anchor until it is null, then we're done.  
 *
 *              For each mapping, we call the remove routine to remove it from the PTEG hash list and 
 *              decriment the pmap's residency count.  Then we release the mapping back to the free list.
 *
 */
 

void mapping_purge_pmap(struct phys_entry *pp, pmap_t pmap) {           /* Remove all mappings from specified pmap for this physent */

        mapping         *mp, *mp_next, *mpv;
        spl_t           s;
        unsigned int *useadd, *useaddr, uindx;
        int i;
                
        s=splhigh();                                                                    /* Don't bother me */
        
        if(!hw_lock_bit((unsigned int *)&pp->phys_link, PHYS_LOCK, LockTimeOut)) {      /* Lock the physical entry */
                panic("\nmapping_purge_pmap: Timeout attempting to lock physical entry at %08X: %08X %08X\n", 
                        pp, pp->phys_link, pp->pte1);   /* Complain about timeout */
        }

        mp = (mapping *)((unsigned int)pp->phys_link & ~PHYS_FLAGS);
        
        while(mp) {     /* Keep going so long as there's another */

                mpv = hw_cpv(mp);                                       /* Get the virtual address */
                if(mpv->pmap != pmap) {
                        mp = (mapping *)((unsigned int)mpv->next & ~PHYS_FLAGS);
                        continue;
                }
#if DEBUG
                if(hw_atomic_sub(&mpv->pmap->stats.resident_count, 1) < 0) panic("pmap resident count went negative\n");
#else
                (void)hw_atomic_sub(&mpv->pmap->stats.resident_count, 1);       /* Decrement the resident page count */
#endif

                uindx = ((mpv->PTEv >> 24) & 0x78) | ((mpv->PTEv >> 3) & 7);    /* Join seg # and top 2 bits of API */
                useadd = (unsigned int *)&mpv->pmap->pmapUsage[uindx];  /* Point to slot to bump */
                useaddr = (unsigned int *)((unsigned int)useadd & -4);  /* Round down to word */
                (void)hw_atomic_sub(useaddr, (useaddr == useadd) ? 0x00010000 : 1); /* Incr the even or odd slot */

        
        
                mp_next = (mapping *)((unsigned int)mpv->next & ~PHYS_FLAGS);
                hw_rem_map(mp);                                         /* Remove the mapping */
                mapping_free(mpv);                                      /* Add mapping to the free list */
                mp = mp_next;
        }
                
        hw_unlock_bit((unsigned int *)&pp->phys_link, PHYS_LOCK);       /* We're done, unlock the physical entry */
        splx(s);
        return;
}
/*
 *              mapping_purge(struct phys_entry *pp) - release all mappings for this physent to the free list 
 *
 *              This guy releases any mappings that exist for a physical page.
 *              We get the lock on the phys_entry, and hold it through out this whole routine.
 *              That way, no one can change the queue out from underneath us.  We keep fetching
 *              the physents mapping anchor until it is null, then we're done.  
 *
 *              For each mapping, we call the remove routine to remove it from the PTEG hash list and 
 *              decriment the pmap's residency count.  Then we release the mapping back to the free list.
 *
 */
 
void mapping_purge(struct phys_entry *pp) {                                             /* Remove all mappings for this physent */

        mapping         *mp, *mpv;
        spl_t           s;
        unsigned int *useadd, *useaddr, uindx;
        int i;
                
        s=splhigh();                                                                                            /* Don't bother me */
        debugLog2(3, pp->pte1, 0);                                                                      /* start mapping_purge */
        
        if(!hw_lock_bit((unsigned int *)&pp->phys_link, PHYS_LOCK, LockTimeOut)) {              /* Lock the physical entry */
                panic("\nmapping_purge: Timeout attempting to lock physical entry at %08X: %08X %08X\n", 
                        pp, pp->phys_link, pp->pte1);   /* Complain about timeout */
        }
        
        while(mp = (mapping *)((unsigned int)pp->phys_link & ~PHYS_FLAGS)) {    /* Keep going so long as there's another */

                mpv = hw_cpv(mp);                                                                               /* Get the virtual address */
#if DEBUG
                if(hw_atomic_sub(&mpv->pmap->stats.resident_count, 1) < 0) panic("pmap resident count went negative\n");
#else
                (void)hw_atomic_sub(&mpv->pmap->stats.resident_count, 1);       /* Decrement the resident page count */
#endif

                uindx = ((mpv->PTEv >> 24) & 0x78) | ((mpv->PTEv >> 3) & 7);    /* Join segment number and top 2 bits of the API */
                useadd = (unsigned int *)&mpv->pmap->pmapUsage[uindx];  /* Point to slot to bump */
                useaddr = (unsigned int *)((unsigned int)useadd & -4);  /* Round down to word */
                (void)hw_atomic_sub(useaddr, (useaddr == useadd) ? 0x00010000 : 1);     /* Increment the even or odd slot */

#if 0
        for(i = 0; i < (pmapUsageMask + 1); i++) {                                      /* (TEST/DEBUG) */
                if((mpv->pmap->pmapUsage[i]) > 8192) {                                  /* (TEST/DEBUG) */
                        panic("mapping_remove: pmapUsage slot for %08X has invalid count (%d) for pmap %08X\n",
                                i * pmapUsageSize, mpv->pmap->pmapUsage[i], mpv->pmap);
                }
        }
#endif
        
        
                hw_rem_map(mp);                                                                                 /* Remove the mapping */
                mapping_free(mpv);                                                                              /* Add mapping to the free list */
        }
                
        hw_unlock_bit((unsigned int *)&pp->phys_link, PHYS_LOCK);       /* We're done, unlock the physical entry */
        
        debugLog2(4, pp->pte1, 0);                                                                      /* end mapping_purge */
        splx(s);                                                                                                        /* Was there something you needed? */
        return;                                                                                                         /* Tell them we did it */
}


/*
 *              mapping_make(pmap, pp, va, spa, prot, attr, locked) - map a virtual address to a real one 
 *
 *              This routine takes the given parameters, builds a mapping block, and queues it into the 
 *              correct lists.
 *              
 *              The pp parameter can be null.  This allows us to make a mapping that is not
 *              associated with any physical page.  We may need this for certain I/O areas.
 *
 *              If the phys_entry address is null, we neither lock or chain into it.
 *              If locked is 1, we already hold the lock on the phys_entry and won't get nor release it.
 */
 
mapping *mapping_make(pmap_t pmap, struct phys_entry *pp, vm_offset_t va, vm_offset_t pa, vm_prot_t prot, int attr, boolean_t locked) { /* Make an address mapping */

        register mapping *mp, *mpv;
        unsigned int *useadd, *useaddr;
        spl_t           s;
        int i;

        debugLog2(5, va, pa);                                                                           /* start mapping_purge */
        mpv = mapping_alloc();                                                                          /* Get a spare mapping block */
        
        mpv->pmap = pmap;                                                                                       /* Initialize the pmap pointer */
        mpv->physent = pp;                                                                                      /* Initialize the pointer to the physical entry */
        mpv->PTEr = ((unsigned int)pa & ~(PAGE_SIZE - 1)) | attr<<3 | ppc_prot(prot);   /* Build the real portion of the PTE */
        mpv->PTEv = (((unsigned int)va >> 1) & 0x78000000) | (pmap->space << 7) | (((unsigned int)va >> 22) & 0x0000003F);      /* Build the VSID */

        s=splhigh();                                                                                            /* Don't bother from now on */
        
        mp = hw_cvp(mpv);                                                                                       /* Get the physical address of this */

        if(pp && !locked) {                                                                                     /* Is there a physical entry? Or do we already hold the lock? */
                if(!hw_lock_bit((unsigned int *)&pp->phys_link, PHYS_LOCK, LockTimeOut)) {      /* Lock the physical entry */
                        panic("\nmapping_make: Timeout attempting to lock physical entry at %08X: %08X %08X\n", 
                                pp, pp->phys_link, pp->pte1);                                   /* Complain about timeout */
                }
        }
                
        if(pp) {                                                                                                        /* See of there is a physcial entry */
                mpv->next = (mapping *)((unsigned int)pp->phys_link & ~PHYS_FLAGS);             /* Move the old anchor to the new mappings forward */
                pp->phys_link = (mapping *)((unsigned int)mp | (unsigned int)pp->phys_link & PHYS_FLAGS);       /* Point the anchor at us.  Now we're on the list (keep the flags) */
        }
        
        hw_add_map(mp, pmap->space, va);                                                        /* Stick it on the PTEG hash list */
        
        (void)hw_atomic_add(&mpv->pmap->stats.resident_count, 1);       /* Increment the resident page count */
        useadd = (unsigned int *)&pmap->pmapUsage[(va >> pmapUsageShft) & pmapUsageMask];       /* Point to slot to bump */
        useaddr = (unsigned int *)((unsigned int)useadd & -4);          /* Round down to word */
        (void)hw_atomic_add(useaddr, (useaddr == useadd) ? 0x00010000 : 1);     /* Increment the even or odd slot */
#if 0
        for(i = 0; i < (pmapUsageMask + 1); i++) {                                      /* (TEST/DEBUG) */
                if((mpv->pmap->pmapUsage[i]) > 8192) {                                  /* (TEST/DEBUG) */
                        panic("mapping_remove: pmapUsage slot for %08X has invalid count (%d) for pmap %08X\n",
                                i * pmapUsageSize, mpv->pmap->pmapUsage[i], mpv->pmap);
                }
        }
#endif

        if(pp && !locked)hw_unlock_bit((unsigned int *)&pp->phys_link, PHYS_LOCK);      /* If we have one and we didn't hold on entry, unlock the physical entry */
                
        splx(s);                                                                                                        /* Ok for interruptions now */
        debugLog2(6, pmap->space, prot);                                                        /* end mapping_purge */
        return mpv;                                                                                                     /* Leave... */
}


/*
 *              Enters optimal translations for odd-sized V=F blocks.
 *
 *              Builds a block map for each power-of-two hunk o' address
 *              that exists.  This is specific to the processor type.  
 *              PPC uses BAT register size stuff.  Future PPC might have
 *              something else.
 *
 *              The supplied va is expected to be maxoptimal vs the supplied boundary. We're too
 *              stupid to know otherwise so we only look at the va anyhow, so there...
 *
 */
 
void mapping_block_map_opt(pmap_t pmap, vm_offset_t va, vm_offset_t pa, vm_offset_t bnd, vm_size_t size, vm_prot_t prot, int attr) {    /* Maps optimal autogenned blocks */

        register blokmap *blm, *oblm;
        unsigned int    pg;
        unsigned int    maxsize, boundary, leading, trailing, cbsize, minsize, tomin;
        int                             i, maxshft, nummax, minshft;

#if 1
        kprintf("mapping_block_map_opt: pmap=%08X; va=%08X; pa=%08X; ; bnd=%08X; size=%08X; prot=%08X; attr=%08X\n",    /* (TEST/DEBUG) */
         pmap, va, pa, bnd, size, prot, attr);
#endif
        
        minsize = blokValid ^ (blokValid & (blokValid - 1));    /* Set minimum subblock size */
        maxsize = 0x80000000 >> cntlzw(blokValid);              /* Set maximum subblock size */
        
        minshft = 31 - cntlzw(minsize);                                 /* Shift to position minimum size */
        maxshft = 31 - cntlzw(blokValid);                               /* Shift to position maximum size */
        
        leading = ((va + bnd - 1) & -bnd) - va;                 /* Get size of leading area */
        trailing = size - leading;                                              /* Get size of trailing area */
        tomin = ((va + minsize - 1) & -minsize) - va;   /* Get size needed to round up to the minimum block size */
        
#if 1
        kprintf("mapping_block_map_opt: bnd=%08X; leading=%08X; trailing=%08X; tomin=%08X\n", bnd, leading, trailing, tomin);           /* (TEST/DEBUG) */
#endif

        if(tomin)pmap_map_block(pmap, va, pa, tomin, prot, attr, 0); /* Map up to minimum block size */
        
        va = va + tomin;                                                                /* Adjust virtual start */
        pa = pa + tomin;                                                                /* Adjust physical start */
        leading = leading - tomin;                                              /* Adjust leading size */
        
/*
 *      Some of this code is very classic PPC.  We need to fix this up.
 */
 
        leading = leading >> minshft;                                   /* Position for bit testing */
        cbsize = minsize;                                                               /* Set the minimum size */
        
        for(i = 0; i < (maxshft - minshft + 1); i ++) { /* Cycle through all block sizes, small to large */
                
                if(leading & 1) {               
                        pmap_map_block(pmap, va, pa, cbsize, prot, attr, 0); /* Map up to next boundary */
                        pa = pa + cbsize;                                               /* Bump up physical address */
                        va = va + cbsize;                                               /* Bump up virtual address */
                }
        
                leading = leading >> 1;                                         /* Shift up to next size */
                cbsize = cbsize << 1;                                           /* Here too */

        }
        
        nummax = trailing >> maxshft;                                   /* Get number of max size blocks left */
        for(i=0; i < nummax - 1; i++) {                                 /* Account for all max size block left but 1 */
                pmap_map_block(pmap, va, pa, maxsize, prot, attr, 0); /* Map up to next boundary */

                pa = pa + maxsize;                                                      /* Bump up physical address */
                va = va + maxsize;                                                      /* Bump up virtual address */
                trailing -= maxsize;                                            /* Back off what we just did */
        }
        
        cbsize = maxsize;                                                               /* Start at maximum size */
        
        for(i = 0; i < (maxshft - minshft + 1); i ++) { /* Cycle through all block sizes, high to low */
                
                if(trailing & cbsize) { 
                        trailing &= ~cbsize;                                    /* Remove the block we are allocating */                                                
                        pmap_map_block(pmap, va, pa, cbsize, prot, attr, 0); /* Map up to next boundary */
                        pa = pa + cbsize;                                               /* Bump up physical address */
                        va = va + cbsize;                                               /* Bump up virtual address */
                }       
                cbsize = cbsize >> 1;                                           /* Next size down */
        }
        
        if(trailing) pmap_map_block(pmap, va, pa, trailing, prot, attr, 0); /* Map up to end */
        
        return;                                                                                                 /* Return */
}


/*
 *              Enters translations for odd-sized V=F blocks.
 *
 *              Checks to insure that the request is at least ODDBLKMIN in size.  If smaller, the request
 *              will be split into normal-sized page mappings.
 *
 *              The higher level VM map should be locked to insure that we don't have a
 *              double diddle here.
 *
 *              We panic if we get a block that overlaps with another. We do not merge adjacent
 *              blocks because removing any address within a block removes the entire block and if
 *              would really mess things up if we trashed too much.
 *
 *              Once a block is mapped, it is unmutable, that is, protection, catch mode, etc. can
 *              not be changed.  The block must be unmapped and then remapped with the new stuff.
 *              We also do not keep track of reference or change flags.
 *
 *              Blocks are kept in MRU order anchored from the pmap. The chain is traversed only
 *              with interruptions and translation disabled and under the control of the lock located
 *              in the first block map. MRU is used because it is expected that the same entry 
 *              will be accessed repeatedly while PTEs are being generated to cover those addresses.
 *
 */
 
void pmap_map_block(pmap_t pmap, vm_offset_t va, vm_offset_t pa, vm_size_t size, vm_prot_t prot, int attr, unsigned int flags) {        /* Map an autogenned block */

        register blokmap *blm, *oblm, *oblm_virt;;
        unsigned int pg;

#if 0
        kprintf("pmap_map_block: pmap=%08X; va=%08X; pa=%08X; size=%08X; prot=%08X; attr=%08X\n",       /* (TEST/DEBUG) */
         pmap, va, pa, size, prot, attr);
#endif

        if(size < ODDBLKMIN) {                                                                  /* Is this below the minimum size? */
                for(pg = 0; pg < size; pg += PAGE_SIZE) {                       /* Add all pages in this block */
                        mapping_make(pmap, 0, va + pg, pa + pg, prot, attr, 0); /* Map this page on in */
#if 0
                        kprintf("pmap_map_block: mm: va=%08X; pa=%08X\n",       /* (TEST/DEBUG) */
                                va + pg, pa + pg);
#endif
                }
                return;                                                                                         /* All done */
        }
        
        blm = (blokmap *)mapping_alloc();                                               /* Get a block mapping */
        
        blm->start = (unsigned int)va & -PAGE_SIZE;                             /* Get virtual block start */
        blm->end = (blm->start + size - 1) | (PAGE_SIZE - 1);   /* Get virtual block end */
        blm->current = 0;
        blm->PTEr = ((unsigned int)pa & -PAGE_SIZE) | attr<<3 | ppc_prot(prot); /* Build the real portion of the base PTE */
        blm->space = pmap->space;                                                               /* Set the space (only needed for remove) */
        blm->blkFlags = flags;                                                                  /* Set the block's flags */
        
#if 0
        kprintf("pmap_map_block: bm=%08X; start=%08X; end=%08X; PTEr=%08X\n",   /* (TEST/DEBUG) */
         blm, blm->start, blm->end, blm->PTEr);
#endif

        blm = (blokmap *)hw_cvp((mapping *)blm);                                /* Get the physical address of this */

#if 0
        kprintf("pmap_map_block: bm (real)=%08X; pmap->bmaps=%08X\n",   /* (TEST/DEBUG) */
         blm, pmap->bmaps);
#endif

        do {
                oblm = hw_add_blk(pmap, blm); 
                if ((unsigned int)oblm & 2) {
                        oblm_virt = (blokmap *)hw_cpv((mapping *)((unsigned int)oblm & 0xFFFFFFFC));
                        mapping_remove(pmap, oblm_virt->start);
                };
        } while ((unsigned int)oblm & 2);

        if (oblm) {
                oblm = (blokmap *)hw_cpv((mapping *) oblm);                             /* Get the old block virtual address */
                blm = (blokmap *)hw_cpv((mapping *)blm);                                /* Back to the virtual address of this */
                if((oblm->start != blm->start) ||                                       /* If we have a match, then this is a fault race and */
                                (oblm->end != blm->end) ||                              /* is acceptable */
                                (oblm->PTEr != blm->PTEr))
                        panic("pmap_map_block: block map overlap - blm = %08X\n", oblm);/* Otherwise, Squeak loudly and carry a big stick */
                mapping_free((struct mapping *)blm);
        }

#if 0
        kprintf("pmap_map_block: pmap->bmaps=%08X\n",                   /* (TEST/DEBUG) */
         blm, pmap->bmaps);
#endif

        return;                                                                                                 /* Return */
}


/*
 *              Optimally enters translations for odd-sized V=F blocks.
 *
 *              Checks to insure that the request is at least ODDBLKMIN in size.  If smaller, the request
 *              will be split into normal-sized page mappings.
 *
 *              This one is different than pmap_map_block in that it will allocate it's own virtual
 *              target address. Rather than allocating a single block,
 *              it will also allocate multiple blocks that are power-of-two aligned/sized.  This allows
 *              hardware-level mapping that takes advantage of BAT maps or large page sizes.
 *
 *              Most considerations for pmap_map_block apply.
 *
 *
 */
 
kern_return_t pmap_map_block_opt(vm_map_t map, vm_offset_t *va, 
        vm_offset_t pa, vm_size_t size, vm_prot_t prot, int attr) {     /* Map an optimal autogenned block */

        register blokmap *blm, *oblm;
        unsigned int    pg;
    kern_return_t       err;
        unsigned int    bnd;

#if 1
        kprintf("pmap_map_block_opt: map=%08X; pa=%08X; size=%08X; prot=%08X; attr=%08X\n",     /* (TEST/DEBUG) */
                map, pa, size, prot, attr);
#endif

        if(size < ODDBLKMIN) {                                                                  /* Is this below the minimum size? */
                err = vm_allocate(map, va, size, VM_FLAGS_ANYWHERE);    /* Make us some memories */
                if(err) {
#if DEBUG
                        kprintf("pmap_map_block_opt: vm_allocate() returned %d\n", err);        /* Say we died */
#endif
                        return(err);                                                                    /* Pass back the error */
                }
#if 1
                kprintf("pmap_map_block_opt: small; vaddr = %08X\n", *va);      /* (TEST/DEBUG) */
#endif

                for(pg = 0; pg < size; pg += PAGE_SIZE) {                       /* Add all pages in this block */
                        mapping_make(map->pmap, 0, *va + pg, pa + pg, prot, attr, 0);   /* Map this page on in */
                }
                return(KERN_SUCCESS);                                                           /* All done */
        }
        
        err = vm_map_block(map, va, &bnd, pa, size, prot);              /* Go get an optimal allocation */

        if(err == KERN_INVALID_ADDRESS) {                                               /* Can we try a brute force block mapping? */
                err = vm_allocate(map, va, size, VM_FLAGS_ANYWHERE);    /* Make us some memories */
                if(err) {
#if DEBUG
                        kprintf("pmap_map_block_opt: non-optimal vm_allocate() returned %d\n", err);    /* Say we died */
#endif
                        return(err);                                                                    /* Pass back the error */
                }
#if 1
                kprintf("pmap_map_block_opt: non-optimal - vaddr = %08X\n", *va);       /* (TEST/DEBUG) */
#endif
                pmap_map_block(map->pmap, *va, pa, size, prot, attr, 0);        /* Set up a block mapped area */
                return KERN_SUCCESS;                                                            /* All done now */
        }

        if(err != KERN_SUCCESS) {                                                               /* We couldn't get any address range to map this... */
#if DEBUG
                kprintf("pmap_map_block_opt: vm_allocate() returned %d\n", err);        /* Say we couldn' do it */
#endif
                return(err);
        }

#if 1
        kprintf("pmap_map_block_opt: optimal - vaddr=%08X; bnd=%08X\n", *va, bnd);      /* (TEST/DEBUG) */
#endif
        mapping_block_map_opt(map->pmap, *va, pa, bnd, size, prot, attr);       /* Go build the maps */
        return(KERN_SUCCESS);                                                                   /* All done */
}


#if 0

/*
 *              Enters translations for odd-sized V=F blocks and merges adjacent or overlapping
 *              areas.
 *
 *              Once blocks are merged, they act like one block, i.e., if you remove it,
 *              it all goes...
 *
 *              This can only be used during boot.  Ain't no way we can handle SMP
 *              or preemption easily, so we restrict it.  We don't check either. We
 *              assume only skilled professional programmers will attempt using this
 *              function. We assume no responsibility, either real or imagined, for
 *              injury or death resulting from unauthorized use of this function.
 *
 *              No user servicable parts inside. Notice to be removed by end-user only,
 *              under penalty of applicable federal and state laws.
 *
 *              See descriptions of pmap_map_block. Ignore the part where we say we panic for
 *              overlapping areas.  Note that we do panic if we can't merge.
 *
 */
 
void pmap_map_block_merge(pmap_t pmap, vm_offset_t va, vm_offset_t pa, vm_size_t size, vm_prot_t prot, int attr) {      /* Map an autogenned block */

        register blokmap *blm, *oblm;
        unsigned int pg;
        spl_t           s;

#if 1
        kprintf("pmap_map_block_merge: pmap=%08X; va=%08X; pa=%08X; size=%08X; prot=%08X; attr=%08X\n", /* (TEST/DEBUG) */
         pmap, va, pa, size, prot, attr);
#endif

        s=splhigh();                                                                                            /* Don't bother from now on */
        if(size < ODDBLKMIN) {                                                                          /* Is this below the minimum size? */
                for(pg = 0; pg < size; pg += PAGE_SIZE) {                               /* Add all pages in this block */
                        mapping_make(pmap, 0, va + pg, pa + pg, prot, attr, 0); /* Map this page on in */
                }
                return;                                                                                                 /* All done */
        }
        
        blm = (blokmap *)mapping_alloc();                                                       /* Get a block mapping */
        
        blm->start = (unsigned int)va & -PAGE_SIZE;                                     /* Get virtual block start */
        blm->end = (blm->start + size - 1) | (PAGE_SIZE - 1);           /* Get virtual block end */
        blm->PTEr = ((unsigned int)pa & -PAGE_SIZE) | attr<<3 | ppc_prot(prot); /* Build the real portion of the base PTE */
        
#if 1
        kprintf("pmap_map_block_merge: bm=%08X; start=%08X; end=%08X; PTEr=%08X\n",     /* (TEST/DEBUG) */
         blm, blm->start, blm->end, blm->PTEr);
#endif

        blm = (blokmap *)hw_cvp((mapping *)blm);                                        /* Get the physical address of this */

#if 1
        kprintf("pmap_map_block_merge: bm (real)=%08X; pmap->bmaps=%08X\n",     /* (TEST/DEBUG) */
         blm, pmap->bmaps);
#endif

        if(oblm = hw_add_blk(pmap, blm)) {                                                      /* Add to list and make sure we don't overlap anything */
                panic("pmap_map_block_merge: block map overlap - blm = %08X\n", oblm);  /* Squeak loudly and carry a big stick */
        }

#if 1
        kprintf("pmap_map_block_merge: pmap->bmaps=%08X\n",                     /* (TEST/DEBUG) */
         blm, pmap->bmaps);
#endif
        splx(s);                                                                                                        /* Ok for interruptions now */

        return;                                                                                                         /* Return */
}
#endif

/*
 *              void mapping_protect_phys(phys_entry *pp, vm_prot_t prot) - change the protection of a physical page
 *
 *              This routine takes a physical entry and runs through all mappings attached to it and changes
 *              the protection.  If there are PTEs associated with the mappings, they will be invalidated before
 *              the protection is changed.  We don't try to save the PTE.  We won't worry about the LRU calculations
 *              either (I don't think, maybe I'll change my mind later).  There is no limitation on changes, e.g., 
 *              higher to lower, lower to higher.
 *
 *              Phys_entry is unlocked.
 */

void mapping_protect_phys(struct phys_entry *pp, vm_prot_t prot, boolean_t locked) {    /* Change protection of all mappings to page */

        spl_t                           spl;
        
        debugLog2(9, pp->pte1, prot);                                                           /* end remap */
        spl=splhigh();                                                                                          /* No interruptions during this */
        if(!locked) {                                                                                           /* Do we need to lock the physent? */
                if(!hw_lock_bit((unsigned int *)&pp->phys_link, PHYS_LOCK, LockTimeOut)) {      /* Lock the physical entry */
                        panic("\nmapping_protect: Timeout attempting to lock physical entry at %08X: %08X %08X\n", 
                                pp, pp->phys_link, pp->pte1);                                           /* Complain about timeout */
                }
        }       

        hw_prot(pp, ppc_prot(prot));                                                            /* Go set the protection on this physical page */

        if(!locked) hw_unlock_bit((unsigned int *)&pp->phys_link, PHYS_LOCK);   /* We're done, unlock the physical entry */
        splx(spl);                                                                                                      /* Restore interrupt state */
        debugLog2(10, pp->pte1, 0);                                                                     /* end remap */
        
        return;                                                                                                         /* Leave... */
}

/*
 *              void mapping_protect(pmap_t pmap, vm_offset_t vaddr, vm_prot_t prot) - change the protection of a virtual page
 *
 *              This routine takes a pmap and virtual address and changes
 *              the protection.  If there are PTEs associated with the mappings, they will be invalidated before
 *              the protection is changed.  We don't try to save the PTE.  We won't worry about the LRU calculations
 *              either (I don't think, maybe I'll change my mind later).  There is no limitation on changes, e.g., 
 *              higher to lower, lower to higher.
 *
 */

void mapping_protect(pmap_t pmap, vm_offset_t vaddr, vm_prot_t prot) {  /* Change protection of a virtual page */

        mapping         *mp, *mpv;
        spl_t           s;

        debugLog2(9, vaddr, pmap);                                      /* start mapping_protect */
        s = splhigh();                                                          /* Don't bother me */
                
        mp = hw_lock_phys_vir(pmap->space, vaddr);      /* Lock the physical entry for this mapping */

        if(!mp) {                                                                       /* Did we find one? */
                splx(s);                                                                /* Restore the interrupt level */
                debugLog2(10, 0, 0);                                            /* end mapping_pmap */
                return;                                                                 /* Didn't find any... */
        }
        if((unsigned int)mp & 1) {                                      /* Did we timeout? */
                panic("mapping_protect: timeout locking physical entry\n");     /* Yeah, scream about it! */
                splx(s);                                                                /* Restore the interrupt level */
                return;                                                                 /* Bad hair day... */
        }
                
        hw_prot_virt(mp, ppc_prot(prot));                       /* Go set the protection on this virtual mapping */

        mpv = hw_cpv(mp);                                                       /* Get virtual address of mapping */
        if(mpv->physent) {                                                      /* If there is a physical page, */
                hw_unlock_bit((unsigned int *)&mpv->physent->phys_link, PHYS_LOCK);     /* Unlock the physical entry */
        }
        splx(s);                                                                        /* Restore interrupt state */
        debugLog2(10, mpv->PTEr, 0);                            /* end remap */
        
        return;                                                                         /* Leave... */
}

/*
 *              mapping_phys_attr(struct phys_entry *pp, vm_prot_t prot, unsigned int wimg) Sets the default physical page attributes
 *
 *              This routine takes a physical entry and sets the physical attributes.  There can be no mappings
 *              associated with this page when we do it.
 */

void mapping_phys_attr(struct phys_entry *pp, vm_prot_t prot, unsigned int wimg) {      /* Sets the default physical page attributes */

        debugLog2(11, pp->pte1, prot);                                                          /* end remap */

        if(!hw_lock_bit((unsigned int *)&pp->phys_link, PHYS_LOCK, LockTimeOut)) {      /* Lock the physical entry */
                panic("\nmapping_phys_attr: Timeout attempting to lock physical entry at %08X: %08X %08X\n", 
                        pp, pp->phys_link, pp->pte1);                                           /* Complain about timeout */
        }

        hw_phys_attr(pp, ppc_prot(prot), wimg);                                         /* Go set the default WIMG and protection */

        hw_unlock_bit((unsigned int *)&pp->phys_link, PHYS_LOCK);       /* We're done, unlock the physical entry */
        debugLog2(12, pp->pte1, wimg);                                                          /* end remap */
        
        return;                                                                                                         /* Leave... */
}

/*
 *              void mapping_invall(phys_entry *pp) - invalidates all ptes associated with a page
 *
 *              This routine takes a physical entry and runs through all mappings attached to it and invalidates
 *              any PTEs it finds.
 *
 *              Interruptions must be disabled and the physical entry locked at entry.
 */

void mapping_invall(struct phys_entry *pp) {                                    /* Clear all PTEs pointing to a physical page */

        hw_inv_all(pp);                                                                                         /* Go set the change bit of a physical page */
        
        return;                                                                                                         /* Leave... */
}


/*
 *              void mapping_clr_mod(phys_entry *pp) - clears the change bit of a physical page
 *
 *              This routine takes a physical entry and runs through all mappings attached to it and turns
 *              off the change bit.  If there are PTEs associated with the mappings, they will be invalidated before
 *              the change bit is changed.  We don't try to save the PTE.  We won't worry about the LRU calculations
 *              either (I don't think, maybe I'll change my mind later).
 *
 *              Interruptions must be disabled and the physical entry locked at entry.
 */

void mapping_clr_mod(struct phys_entry *pp) {                                   /* Clears the change bit of a physical page */

        hw_clr_mod(pp);                                                                                         /* Go clear the change bit of a physical page */
        return;                                                                                                         /* Leave... */
}


/*
 *              void mapping_set_mod(phys_entry *pp) - set the change bit of a physical page
 *
 *              This routine takes a physical entry and runs through all mappings attached to it and turns
 *              on the change bit.  If there are PTEs associated with the mappings, they will be invalidated before
 *              the change bit is changed.  We don't try to save the PTE.  We won't worry about the LRU calculations
 *              either (I don't think, maybe I'll change my mind later).
 *
 *              Interruptions must be disabled and the physical entry locked at entry.
 */

void mapping_set_mod(struct phys_entry *pp) {                                   /* Sets the change bit of a physical page */

        hw_set_mod(pp);                                                                                         /* Go set the change bit of a physical page */
        return;                                                                                                         /* Leave... */
}


/*
 *              void mapping_clr_ref(struct phys_entry *pp) - clears the reference bit of a physical page
 *
 *              This routine takes a physical entry and runs through all mappings attached to it and turns
 *              off the reference bit.  If there are PTEs associated with the mappings, they will be invalidated before
 *              the reference bit is changed.  We don't try to save the PTE.  We won't worry about the LRU calculations
 *              either (I don't think, maybe I'll change my mind later).
 *
 *              Interruptions must be disabled at entry.
 */

void mapping_clr_ref(struct phys_entry *pp) {                                   /* Clears the reference bit of a physical page */

        mapping *mp;

        debugLog2(13, pp->pte1, 0);                                                                     /* end remap */
        if(!hw_lock_bit((unsigned int *)&pp->phys_link, PHYS_LOCK, LockTimeOut)) {      /* Lock the physical entry for this mapping */
                panic("Lock timeout getting lock on physical entry\n"); /* Just die... */
        }
        hw_clr_ref(pp);                                                                                         /* Go clear the reference bit of a physical page */
        hw_unlock_bit((unsigned int *)&pp->phys_link, PHYS_LOCK);       /* Unlock physical entry */
        debugLog2(14, pp->pte1, 0);                                                                     /* end remap */
        return;                                                                                                         /* Leave... */
}


/*
 *              void mapping_set_ref(phys_entry *pp) - set the reference bit of a physical page
 *
 *              This routine takes a physical entry and runs through all mappings attached to it and turns
 *              on the reference bit.  If there are PTEs associated with the mappings, they will be invalidated before
 *              the reference bit is changed.  We don't try to save the PTE.  We won't worry about the LRU calculations
 *              either (I don't think, maybe I'll change my mind later).
 *
 *              Interruptions must be disabled and the physical entry locked at entry.
 */

void mapping_set_ref(struct phys_entry *pp) {                                   /* Sets the reference bit of a physical page */

        hw_set_ref(pp);                                                                                         /* Go set the reference bit of a physical page */
        return;                                                                                                         /* Leave... */
}


/*
 *              void mapping_tst_mod(phys_entry *pp) - test the change bit of a physical page
 *
 *              This routine takes a physical entry and runs through all mappings attached to it and tests
 *              the changed bit.  If there are PTEs associated with the mappings, they will be invalidated before
 *              the changed bit is tested.  We don't try to save the PTE.  We won't worry about the LRU calculations
 *              either (I don't think, maybe I'll change my mind later).
 *
 *              Interruptions must be disabled and the physical entry locked at entry.
 */

boolean_t mapping_tst_mod(struct phys_entry *pp) {                              /* Tests the change bit of a physical page */

        return(hw_tst_mod(pp));                                                                         /* Go test the change bit of a physical page */
}


/*
 *              void mapping_tst_ref(phys_entry *pp) - tests the reference bit of a physical page
 *
 *              This routine takes a physical entry and runs through all mappings attached to it and tests
 *              the reference bit.  If there are PTEs associated with the mappings, they will be invalidated before
 *              the reference bit is changed.  We don't try to save the PTE.  We won't worry about the LRU calculations
 *              either (I don't think, maybe I'll change my mind later).
 *
 *              Interruptions must be disabled and the physical entry locked at entry.
 */

boolean_t mapping_tst_ref(struct phys_entry *pp) {                              /* Tests the reference bit of a physical page */

        return(hw_tst_ref(pp));                                                                         /* Go test the reference bit of a physical page */
}


/*
 *              void mapping_phys_init(physent, wimg) - fills in the default processor dependent areas of the phys ent
 *
 *              Currently, this sets the default word 1 of the PTE.  The only bits set are the WIMG bits
 */

void mapping_phys_init(struct phys_entry *pp, unsigned int pa, unsigned int wimg) {             /* Initializes hw specific storage attributes */

        pp->pte1 = (pa & -PAGE_SIZE) | ((wimg << 3) & 0x00000078);      /* Set the WIMG and phys addr in the default PTE1 */

        return;                                                                                                         /* Leave... */
}


/*
 *              mapping_adjust(void) - Releases free mapping blocks and/or allocates new ones 
 *
 *              This routine frees any mapping blocks queued to mapCtl.mapcrel. It also checks
 *              the number of free mappings remaining, and if below a threshold, replenishes them.
 *              The list will be replenshed from mapCtl.mapcrel if there are enough.  Otherwise,
 *              a new one is allocated.
 *
 *              This routine allocates and/or memory and must be called from a safe place. 
 *              Currently, vm_pageout_scan is the safest place. We insure that the 
 */

thread_call_t                           mapping_adjust_call;
static thread_call_data_t       mapping_adjust_call_data;

void mapping_adjust(void) {                                                                             /* Adjust free mappings */

        kern_return_t   retr;
        mappingblok     *mb, *mbn;
        spl_t                   s;
        int                             allocsize, i;
        extern int vm_page_free_count;

        if(mapCtl.mapcmin <= MAPPERBLOK) {
                mapCtl.mapcmin = (mem_size / PAGE_SIZE) / 16;

#if DEBUG
                kprintf("mapping_adjust: minimum entries rqrd = %08X\n", mapCtl.mapcmin);
                kprintf("mapping_adjust: free = %08X; in use = %08X; release = %08X\n",
                  mapCtl.mapcfree, mapCtl.mapcinuse, mapCtl.mapcreln);
#endif
        }

        s = splhigh();                                                                                          /* Don't bother from now on */
        if(!hw_lock_to((hw_lock_t)&mapCtl.mapclock, LockTimeOut)) {     /* Lock the control header */ 
                panic("mapping_adjust - timeout getting control lock (1)\n");   /* Tell all and die */
        }
        
        if (mapping_adjust_call == NULL) {
                thread_call_setup(&mapping_adjust_call_data, 
                                  (thread_call_func_t)mapping_adjust, 
                                  (thread_call_param_t)NULL);
                mapping_adjust_call = &mapping_adjust_call_data;
        }

        while(1) {                                                                                                      /* Keep going until we've got enough */
                
                allocsize = mapCtl.mapcmin - mapCtl.mapcfree;                   /* Figure out how much we need */
                if(allocsize < 1) break;                                                                /* Leave if we have all we need */
                
                if((unsigned int)(mbn = mapCtl.mapcrel)) {                              /* Can we rescue a free one? */
                        mapCtl.mapcrel = mbn->nextblok;                                         /* Dequeue it */
                        mapCtl.mapcreln--;                                                                      /* Back off the count */
                        allocsize = MAPPERBLOK;                                                         /* Show we allocated one block */                       
                }
                else {                                                                                                  /* No free ones, try to get it */
                        
                        allocsize = (allocsize + MAPPERBLOK - 1) / MAPPERBLOK;  /* Get the number of pages we need */

                        hw_lock_unlock((hw_lock_t)&mapCtl.mapclock);            /* Unlock our stuff */
                        splx(s);                                                                                        /* Restore 'rupts */

                        for(; allocsize > 0; allocsize >>= 1) {                         /* Try allocating in descending halves */ 
                                retr = kmem_alloc_wired(mapping_map, (vm_offset_t *)&mbn, PAGE_SIZE * allocsize);       /* Find a virtual address to use */
                                if((retr != KERN_SUCCESS) && (allocsize == 1)) {        /* Did we find any memory at all? */
                                        break;
                                }
                                if(retr == KERN_SUCCESS) break;                                 /* We got some memory, bail out... */
                        }
                        allocsize = allocsize * MAPPERBLOK;                                     /* Convert pages to number of maps allocated */
                        s = splhigh();                                                                          /* Don't bother from now on */
                        if(!hw_lock_to((hw_lock_t)&mapCtl.mapclock, LockTimeOut)) {     /* Lock the control header */ 
                                panic("mapping_adjust - timeout getting control lock (2)\n");   /* Tell all and die */
                        }
                }
                if (retr != KERN_SUCCESS)
                        break;                                                                                          /* Fail to alocate, bail out... */
                for(; allocsize > 0; allocsize -= MAPPERBLOK) {                 /* Release one block at a time */
                        mapping_free_init((vm_offset_t)mbn, 0, 1);                      /* Initialize a non-permanent block */
                        mbn = (mappingblok *)((unsigned int)mbn + PAGE_SIZE);   /* Point to the next slot */
                }
                if ((mapCtl.mapcinuse + mapCtl.mapcfree + (mapCtl.mapcreln * (MAPPERBLOK + 1))) > mapCtl.mapcmaxalloc)
                        mapCtl.mapcmaxalloc = mapCtl.mapcinuse + mapCtl.mapcfree + (mapCtl.mapcreln * (MAPPERBLOK + 1));
        }

        if(mapCtl.mapcholdoff) {                                                                        /* Should we hold off this release? */
                mapCtl.mapcrecurse = 0;                                                                 /* We are done now */
                hw_lock_unlock((hw_lock_t)&mapCtl.mapclock);                    /* Unlock our stuff */
                splx(s);                                                                                                /* Restore 'rupts */
                return;                                                                                                 /* Return... */
        }

        mbn = mapCtl.mapcrel;                                                                           /* Get first pending release block */
        mapCtl.mapcrel = 0;                                                                                     /* Dequeue them */
        mapCtl.mapcreln = 0;                                                                            /* Set count to 0 */

        hw_lock_unlock((hw_lock_t)&mapCtl.mapclock);                            /* Unlock our stuff */
        splx(s);                                                                                                        /* Restore 'rupts */

        while((unsigned int)mbn) {                                                                      /* Toss 'em all */
                mb = mbn->nextblok;                                                                             /* Get the next */
                kmem_free(mapping_map, (vm_offset_t) mbn, PAGE_SIZE);   /* Release this mapping block */
                mbn = mb;                                                                                               /* Chain to the next */
        }

        __asm__ volatile("sync");                                                                       /* Make sure all is well */
        mapCtl.mapcrecurse = 0;                                                                         /* We are done now */
        return;
}

/*
 *              mapping_free(mapping *mp) - release a mapping to the free list 
 *
 *              This routine takes a mapping and adds it to the free list.
 *              If this mapping make the block non-empty, we queue it to the free block list.
 *              NOTE: we might want to queue it to the end to keep quelch the pathalogical
 *              case when we get a mapping and free it repeatedly causing the block to chain and unchain.
 *              If this release fills a block and we are above the threshold, we release the block
 */

void mapping_free(struct mapping *mp) {                                                 /* Release a mapping */

        mappingblok     *mb, *mbn;
        spl_t                   s;
        unsigned int    full, mindx;

        mindx = ((unsigned int)mp & (PAGE_SIZE - 1)) >> 5;                      /* Get index to mapping */
        mb = (mappingblok *)((unsigned int)mp & -PAGE_SIZE);            /* Point to the mapping block */

        s = splhigh();                                                                                          /* Don't bother from now on */
        if(!hw_lock_to((hw_lock_t)&mapCtl.mapclock, LockTimeOut)) {     /* Lock the control header */ 
                panic("mapping_free - timeout getting control lock\n"); /* Tell all and die */
        }
        
        full = !(mb->mapblokfree[0] | mb->mapblokfree[1] | mb->mapblokfree[2] | mb->mapblokfree[3]);    /* See if full now */ 
        mb->mapblokfree[mindx >> 5] |= (0x80000000 >> (mindx & 31));    /* Flip on the free bit */
        
        if(full) {                                                                                                      /* If it was full before this: */
                mb->nextblok = mapCtl.mapcnext;                                                 /* Move head of list to us */
                mapCtl.mapcnext = mb;                                                                   /* Chain us to the head of the list */
                if(!((unsigned int)mapCtl.mapclast))
                        mapCtl.mapclast = mb;
        }

        mapCtl.mapcfree++;                                                                                      /* Bump free count */
        mapCtl.mapcinuse--;                                                                                     /* Decriment in use count */
        
        mapCtl.mapcfreec++;                                                                                     /* Count total calls */

        if(mapCtl.mapcfree > mapCtl.mapcmin) {                                          /* Should we consider releasing this? */
                if(((mb->mapblokfree[0] | 0x80000000) & mb->mapblokfree[1] & mb->mapblokfree[2] & mb->mapblokfree[3]) 
                   == 0xFFFFFFFF) {                                                                             /* See if empty now */ 

                        if(mapCtl.mapcnext == mb) {                                                     /* Are we first on the list? */
                                mapCtl.mapcnext = mb->nextblok;                                 /* Unchain us */
                                if(!((unsigned int)mapCtl.mapcnext)) mapCtl.mapclast = 0;       /* If last, remove last */
                        }
                        else {                                                                                          /* We're not first */
                                for(mbn = mapCtl.mapcnext; mbn != 0; mbn = mbn->nextblok) {     /* Search for our block */
                                        if(mbn->nextblok == mb) break;                          /* Is the next one our's? */
                                }
                                if(!mbn) panic("mapping_free: attempt to release mapping block (%08X) not on list\n", mp);
                                mbn->nextblok = mb->nextblok;                                   /* Dequeue us */
                                if(mapCtl.mapclast == mb) mapCtl.mapclast = mbn;        /* If last, make our predecessor last */
                        }
                        
                        if(mb->mapblokflags & mbPerm) {                                         /* Is this permanently assigned? */
                                mb->nextblok = mapCtl.mapcnext;                                 /* Move chain head to us */
                                mapCtl.mapcnext = mb;                                                   /* Chain us to the head */
                                if(!((unsigned int)mb->nextblok)) mapCtl.mapclast = mb; /* If last, make us so */
                        }
                        else {
                                mapCtl.mapcfree -= MAPPERBLOK;                                  /* Remove the block from the free count */
                                mapCtl.mapcreln++;                                                              /* Count on release list */
                                mb->nextblok = mapCtl.mapcrel;                                  /* Move pointer */
                                mapCtl.mapcrel = mb;                                                    /* Chain us in front */
                        }
                }
        }

        if(mapCtl.mapcreln > MAPFRTHRSH) {                                                      /* Do we have way too many releasable mappings? */
                if(hw_compare_and_store(0, 1, &mapCtl.mapcrecurse)) {   /* Make sure we aren't recursing */
                        thread_call_enter(mapping_adjust_call);                         /* Go toss some */
                }
        }
        hw_lock_unlock((hw_lock_t)&mapCtl.mapclock);                            /* Unlock our stuff */
        splx(s);                                                                                                        /* Restore 'rupts */

        return;                                                                                                         /* Bye, dude... */
}


/*
 *              mapping_alloc(void) - obtain a mapping from the free list 
 *
 *              This routine takes a mapping off of the free list and returns it's address.
 *
 *              We do this by finding a free entry in the first block and allocating it.
 *              If this allocation empties the block, we remove it from the free list.
 *              If this allocation drops the total number of free entries below a threshold,
 *              we allocate a new block.
 *
 */

mapping *mapping_alloc(void) {                                                                  /* Obtain a mapping */

        register mapping *mp;
        mappingblok     *mb, *mbn;
        spl_t                   s;
        int                             mindx;
        kern_return_t   retr;

        s = splhigh();                                                                                          /* Don't bother from now on */
        if(!hw_lock_to((hw_lock_t)&mapCtl.mapclock, LockTimeOut)) {     /* Lock the control header */ 
                panic("mapping_alloc - timeout getting control lock\n");        /* Tell all and die */
        }

        if(!(mb = mapCtl.mapcnext)) {                                                           /* Get the first block entry */
                unsigned int                    i;
                struct mappingflush             mappingflush;
                PCA                                             *pca_min, *pca_max;
                PCA                                             *pca_base;

                pca_min = (PCA *)(hash_table_base+hash_table_size);
                pca_max = (PCA *)(hash_table_base+hash_table_size+hash_table_size);

                while (mapCtl.mapcfree <= (MAPPERBLOK*2)) {
                        mapCtl.mapcflush.mappingcnt = 0;
                        pca_base = mapCtl.mapcflush.pcaptr;
                        do {
                                hw_select_mappings(&mapCtl.mapcflush);
                                mapCtl.mapcflush.pcaptr++;
                                if (mapCtl.mapcflush.pcaptr >= pca_max)
                                        mapCtl.mapcflush.pcaptr = pca_min;
                        } while ((mapCtl.mapcflush.mappingcnt == 0) && (mapCtl.mapcflush.pcaptr != pca_base));

                        if ((mapCtl.mapcflush.mappingcnt == 0) && (mapCtl.mapcflush.pcaptr == pca_base)) {
                                hw_lock_unlock((hw_lock_t)&mapCtl.mapclock);
                                panic("mapping_alloc - all mappings are wired\n");
                        }
                        mappingflush = mapCtl.mapcflush;
                        hw_lock_unlock((hw_lock_t)&mapCtl.mapclock);
                        splx(s);
                        for (i=0;i<mappingflush.mappingcnt;i++)
                                mapping_remove(mappingflush.mapping[i].pmap, 
                                               mappingflush.mapping[i].offset);
                        s = splhigh();
                        if(!hw_lock_to((hw_lock_t)&mapCtl.mapclock, LockTimeOut)) {
                                panic("mapping_alloc - timeout getting control lock\n");
                        }
                }
                mb = mapCtl.mapcnext;
        }
        
        if(!(mindx = mapalc(mb))) {                                                                     /* Allocate a slot */
                panic("mapping_alloc - empty mapping block detected at %08X\n", mb);    /* Not allowed to find none */
        }
        
        if(mindx < 0) {                                                                                         /* Did we just take the last one */
                mindx = -mindx;                                                                                 /* Make positive */
                mapCtl.mapcnext = mb->nextblok;                                                 /* Remove us from the list */
                if(!((unsigned int)mapCtl.mapcnext)) mapCtl.mapclast = 0;       /* Removed the last one */
        }
        
        mapCtl.mapcfree--;                                                                                      /* Decrement free count */
        mapCtl.mapcinuse++;                                                                                     /* Bump in use count */
        
        mapCtl.mapcallocc++;                                                                            /* Count total calls */

/*
 *      Note: in the following code, we will attempt to rescue blocks only one at a time.
 *      Eventually, after a few more mapping_alloc calls, we will catch up.  If there are none
 *      rescueable, we will kick the misc scan who will allocate some for us.  We only do this
 *      if we haven't already done it.
 *      For early boot, we are set up to only rescue one block at a time.  This is because we prime
 *      the release list with as much as we need until threads start.
 */
        if(mapCtl.mapcfree < mapCtl.mapcmin) {                                          /* See if we need to replenish */
                if(mbn = mapCtl.mapcrel) {                                                              /* Try to rescue a block from impending doom */
                        mapCtl.mapcrel = mbn->nextblok;                                         /* Pop the queue */
                        mapCtl.mapcreln--;                                                                      /* Back off the count */
                        mapping_free_init((vm_offset_t)mbn, 0, 1);                      /* Initialize a non-permanent block */
                }
                else {                                                                                                  /* We need to replenish */
                        if (mapCtl.mapcfree < (mapCtl.mapcmin / 4)) {
                                if(hw_compare_and_store(0, 1, &mapCtl.mapcrecurse)) {   /* Make sure we aren't recursing */
                                        thread_call_enter(mapping_adjust_call);                 /* Go allocate some more */
                                }
                        }
                }
        }

        hw_lock_unlock((hw_lock_t)&mapCtl.mapclock);                            /* Unlock our stuff */
        splx(s);                                                                                                        /* Restore 'rupts */
        
        mp = &((mapping *)mb)[mindx];                                                           /* Point to the allocated mapping */
    __asm__ volatile("dcbz 0,%0" : : "r" (mp));                                 /* Clean it up */
        return mp;                                                                                                      /* Send it back... */
}


void
consider_mapping_adjust()
{
        spl_t                   s;

        s = splhigh();                                                                                          /* Don't bother from now on */
        if(!hw_lock_to((hw_lock_t)&mapCtl.mapclock, LockTimeOut)) {     /* Lock the control header */ 
                panic("mapping_alloc - timeout getting control lock\n");        /* Tell all and die */
        }

        if (mapCtl.mapcfree < (mapCtl.mapcmin / 4)) {
                if(hw_compare_and_store(0, 1, &mapCtl.mapcrecurse)) {   /* Make sure we aren't recursing */
                        thread_call_enter(mapping_adjust_call);                 /* Go allocate some more */
                }
        }

        hw_lock_unlock((hw_lock_t)&mapCtl.mapclock);                            /* Unlock our stuff */
        splx(s);                                                                                                        /* Restore 'rupts */
        
}



/*
 *              void mapping_free_init(mb, perm) - Adds a block of storage to the free mapping list
 *
 *              The mapping block is a page size area on a page boundary.  It contains 1 header and 127
 *              mappings.  This call adds and initializes a block for use.
 *      
 *              The header contains a chain link, bit maps, a virtual to real translation mask, and
 *              some statistics. Bit maps map each slot on the page (bit 0 is not used because it 
 *              corresponds to the header).  The translation mask is the XOR of the virtual and real
 *              addresses (needless to say, the block must be wired).
 *
 *              We handle these mappings the same way as saveareas: the block is only on the chain so
 *              long as there are free entries in it.
 *
 *              Empty blocks are garbage collected when there are at least mapCtl.mapcmin pages worth of free 
 *              mappings. Blocks marked PERM won't ever be released.
 *
 *              If perm is negative, the mapping is initialized, but immediately queued to the mapCtl.mapcrel
 *              list.  We do this only at start up time. This is done because we only allocate blocks 
 *              in the pageout scan and it doesn't start up until after we run out of the initial mappings.
 *              Therefore, we need to preallocate a bunch, but we don't want them to be permanent.  If we put
 *              them on the release queue, the allocate routine will rescue them.  Then when the
 *              pageout scan starts, all extra ones will be released.
 *
 */


void mapping_free_init(vm_offset_t mbl, int perm, boolean_t locked) {           
                                                                                                                        /* Set's start and end of a block of mappings
                                                                                                                           perm indicates if the block can be released 
                                                                                                                           or goes straight to the release queue .
                                                                                                                           locked indicates if the lock is held already */
                                                                                                                   
        mappingblok     *mb;
        spl_t           s;
        int                     i;
        unsigned int    raddr;

        mb = (mappingblok *)mbl;                                                                /* Start of area */
        
        
        if(perm >= 0) {                                                                                 /* See if we need to initialize the block */
                if(perm) {
                        raddr = (unsigned int)mbl;                                              /* Perm means V=R */
                        mb->mapblokflags = mbPerm;                                              /* Set perm */
                }
                else {
                        raddr = kvtophys(mbl);                                                  /* Get real address */
                        mb->mapblokflags = 0;                                                   /* Set not perm */
                }
                
                mb->mapblokvrswap = raddr ^ (unsigned int)mbl;          /* Form translation mask */
                
                mb->mapblokfree[0] = 0x7FFFFFFF;                                        /* Set first 32 (minus 1) free */
                mb->mapblokfree[1] = 0xFFFFFFFF;                                        /* Set next 32 free */
                mb->mapblokfree[2] = 0xFFFFFFFF;                                        /* Set next 32 free */
                mb->mapblokfree[3] = 0xFFFFFFFF;                                        /* Set next 32 free */
        }
        
        s = splhigh();                                                                                  /* Don't bother from now on */
        if(!locked) {                                                                                   /* Do we need the lock? */
                if(!hw_lock_to((hw_lock_t)&mapCtl.mapclock, LockTimeOut)) {             /* Lock the control header */ 
                        panic("mapping_free_init - timeout getting control lock\n");    /* Tell all and die */
                }
        }
        
        if(perm < 0) {                                                                                  /* Direct to release queue? */
                mb->nextblok = mapCtl.mapcrel;                                          /* Move forward pointer */
                mapCtl.mapcrel = mb;                                                            /* Queue us on in */
                mapCtl.mapcreln++;                                                                      /* Count the free block */
        }
        else {                                                                                                  /* Add to the free list */
                
                mb->nextblok = 0;                                                                       /* We always add to the end */
                mapCtl.mapcfree += MAPPERBLOK;                                          /* Bump count */
                
                if(!((unsigned int)mapCtl.mapcnext)) {                          /* First entry on list? */
                        mapCtl.mapcnext = mapCtl.mapclast = mb;                 /* Chain to us */
                }
                else {                                                                                          /* We are not the first */
                        mapCtl.mapclast->nextblok = mb;                                 /* Point the last to us */
                        mapCtl.mapclast = mb;                                                   /* We are now last */
                }
        }
                
        if(!locked) {                                                                                   /* Do we need to unlock? */
                hw_lock_unlock((hw_lock_t)&mapCtl.mapclock);            /* Unlock our stuff */
        }
                splx(s);                                                                                        /* Restore 'rupts */
        return;                                                                                                 /* All done, leave... */
}


/*
 *              void mapping_prealloc(unsigned int) - Preallocates mapppings for large request
 *      
 *              No locks can be held, because we allocate memory here.
 *              This routine needs a corresponding mapping_relpre call to remove the
 *              hold off flag so that the adjust routine will free the extra mapping
 *              blocks on the release list.  I don't like this, but I don't know
 *              how else to do this for now...
 *
 */

void mapping_prealloc(unsigned int size) {                                      /* Preallocates mapppings for large request */

        int     nmapb, i;
        kern_return_t   retr;
        mappingblok     *mbn;
        spl_t           s;

        s = splhigh();                                                                                  /* Don't bother from now on */
        if(!hw_lock_to((hw_lock_t)&mapCtl.mapclock, LockTimeOut)) {             /* Lock the control header */ 
                panic("mapping_prealloc - timeout getting control lock\n");     /* Tell all and die */
        }

        nmapb = (size >> 12) + mapCtl.mapcmin;                                  /* Get number of entries needed for this and the minimum */
        
        mapCtl.mapcholdoff++;                                                                   /* Bump the hold off count */
        
        if((nmapb = (nmapb - mapCtl.mapcfree)) <= 0) {                  /* Do we already have enough? */
                hw_lock_unlock((hw_lock_t)&mapCtl.mapclock);            /* Unlock our stuff */
                splx(s);                                                                                        /* Restore 'rupts */
                return;
        }
        if (!hw_compare_and_store(0, 1, &mapCtl.mapcrecurse)) {                 /* Make sure we aren't recursing */
                hw_lock_unlock((hw_lock_t)&mapCtl.mapclock);                    /* Unlock our stuff */
                splx(s);                                                        /* Restore 'rupts */
                return;
        }
        nmapb = (nmapb + MAPPERBLOK - 1) / MAPPERBLOK;                  /* Get number of blocks to get */
        
        hw_lock_unlock((hw_lock_t)&mapCtl.mapclock);                    /* Unlock our stuff */
        splx(s);                                                                                                /* Restore 'rupts */
        
        for(i = 0; i < nmapb; i++) {                                                    /* Allocate 'em all */
                retr = kmem_alloc_wired(mapping_map, (vm_offset_t *)&mbn, PAGE_SIZE);   /* Find a virtual address to use */
                if(retr != KERN_SUCCESS) {                                                      /* Did we get some memory? */
                        panic("Whoops...  Not a bit of wired memory left for anyone\n");
                }
                mapping_free_init((vm_offset_t)mbn, -1, 0);                     /* Initialize on to the release queue */
        }
        if ((mapCtl.mapcinuse + mapCtl.mapcfree + (mapCtl.mapcreln * (MAPPERBLOK + 1))) > mapCtl.mapcmaxalloc)
                mapCtl.mapcmaxalloc = mapCtl.mapcinuse + mapCtl.mapcfree + (mapCtl.mapcreln * (MAPPERBLOK + 1));

        mapCtl.mapcrecurse = 0;                                                                         /* We are done now */
}

/*
 *              void mapping_relpre(void) - Releases preallocation release hold off
 *      
 *              This routine removes the
 *              hold off flag so that the adjust routine will free the extra mapping
 *              blocks on the release list.  I don't like this, but I don't know
 *              how else to do this for now...
 *
 */

void mapping_relpre(void) {                                                                     /* Releases release hold off */

        spl_t           s;

        s = splhigh();                                                                                  /* Don't bother from now on */
        if(!hw_lock_to((hw_lock_t)&mapCtl.mapclock, LockTimeOut)) {             /* Lock the control header */ 
                panic("mapping_relpre - timeout getting control lock\n");       /* Tell all and die */
        }
        if(--mapCtl.mapcholdoff < 0) {                                                  /* Back down the hold off count */
                panic("mapping_relpre: hold-off count went negative\n");
        }

        hw_lock_unlock((hw_lock_t)&mapCtl.mapclock);                    /* Unlock our stuff */
        splx(s);                                                                                                /* Restore 'rupts */
}

/*
 *              void mapping_free_prime(void) - Primes the mapping block release list
 *
 *              See mapping_free_init.
 *              No locks can be held, because we allocate memory here.
 *              One processor running only.
 *
 */

void mapping_free_prime(void) {                                                                 /* Primes the mapping block release list */

        int     nmapb, i;
        kern_return_t   retr;
        mappingblok     *mbn;
        vm_offset_t     mapping_min;
        
        retr = kmem_suballoc(kernel_map, &mapping_min, MAPPING_MAP_SIZE,
                             FALSE, TRUE, &mapping_map);

        if (retr != KERN_SUCCESS)
                panic("mapping_free_prime: kmem_suballoc failed");


        nmapb = (mapCtl.mapcfree + mapCtl.mapcinuse + MAPPERBLOK - 1) / MAPPERBLOK;     /* Get permanent allocation */
        nmapb = nmapb * 4;                                                                                      /* Get 4 times our initial allocation */

#if DEBUG
        kprintf("mapping_free_prime: free = %08X; in use = %08X; priming = %08X\n", 
          mapCtl.mapcfree, mapCtl.mapcinuse, nmapb);
#endif
        
        for(i = 0; i < nmapb; i++) {                                                            /* Allocate 'em all */
                retr = kmem_alloc_wired(mapping_map, (vm_offset_t *)&mbn, PAGE_SIZE);   /* Find a virtual address to use */
                if(retr != KERN_SUCCESS) {                                                              /* Did we get some memory? */
                        panic("Whoops...  Not a bit of wired memory left for anyone\n");
                }
                mapping_free_init((vm_offset_t)mbn, -1, 0);                             /* Initialize onto release queue */
        }
        if ((mapCtl.mapcinuse + mapCtl.mapcfree + (mapCtl.mapcreln * (MAPPERBLOK + 1))) > mapCtl.mapcmaxalloc)
                mapCtl.mapcmaxalloc = mapCtl.mapcinuse + mapCtl.mapcfree + (mapCtl.mapcreln * (MAPPERBLOK + 1));
}



mapping_fake_zone_info(int *count, vm_size_t *cur_size, vm_size_t *max_size, vm_size_t *elem_size,
                       vm_size_t *alloc_size, int *collectable, int *exhaustable)
{
        *count      = mapCtl.mapcinuse;
        *cur_size   = ((PAGE_SIZE / (MAPPERBLOK + 1)) * (mapCtl.mapcinuse + mapCtl.mapcfree)) + (PAGE_SIZE * mapCtl.mapcreln);
        *max_size   = (PAGE_SIZE / (MAPPERBLOK + 1)) * mapCtl.mapcmaxalloc;
        *elem_size  = (PAGE_SIZE / (MAPPERBLOK + 1));
        *alloc_size = PAGE_SIZE;

        *collectable = 1;
        *exhaustable = 0;
}


/*
 *              vm_offset_t     mapping_p2v(pmap_t pmap, phys_entry *pp) - Finds first virtual mapping of a physical page in a space
 *
 *              Gets a lock on the physical entry.  Then it searches the list of attached mappings for one with
 *              the same space.  If it finds it, it returns the virtual address.
 *
 *              Note that this will fail if the pmap has nested pmaps in it.  Fact is, I'll check
 *              for it and fail it myself...
 */

vm_offset_t     mapping_p2v(pmap_t pmap, struct phys_entry *pp) {               /* Finds first virtual mapping of a physical page in a space */

        spl_t                           s;
        register mapping        *mp, *mpv;
        vm_offset_t                     va;

        if(pmap->vflags & pmapAltSeg) return 0;                                 /* If there are nested pmaps, fail immediately */

        s = splhigh();
        if(!hw_lock_bit((unsigned int *)&pp->phys_link, PHYS_LOCK, LockTimeOut)) {      /* Try to get the lock on the physical entry */
                splx(s);                                                                                        /* Restore 'rupts */
                panic("mapping_p2v: timeout getting lock on physent\n");                        /* Arrrgghhhh! */
                return(0);                                                                                      /* Should die before here */
        }
        
        va = 0;                                                                                                 /* Assume failure */
        
        for(mpv = hw_cpv(pp->phys_link); mpv; mpv = hw_cpv(mpv->next)) {        /* Scan 'em all */
                
                if(!(((mpv->PTEv >> 7) & 0x000FFFFF) == pmap->space)) continue; /* Skip all the rest if this is not the right space... */ 
                
                va = ((((unsigned int)mpv->PTEhash & -64) << 6) ^ (pmap->space  << 12)) & 0x003FF000;   /* Backward hash to the wrapped VADDR */
                va = va | ((mpv->PTEv << 1) & 0xF0000000);                      /* Move in the segment number */
                va = va | ((mpv->PTEv << 22) & 0x0FC00000);                     /* Add in the API for the top of the address */
                break;                                                                                          /* We're done now, pass virtual address back */
        }
        
        hw_unlock_bit((unsigned int *)&pp->phys_link, PHYS_LOCK);                               /* Unlock the physical entry */
        splx(s);                                                                                                /* Restore 'rupts */
        return(va);                                                                                             /* Return the result or 0... */
}

/*
 *      kvtophys(addr)
 *
 *      Convert a kernel virtual address to a physical address
 */
vm_offset_t kvtophys(vm_offset_t va) {

        register mapping                *mp, *mpv;
        register blokmap                *bmp;
        register vm_offset_t    pa;
        spl_t                           s;
        
        s=splhigh();                                                                                    /* Don't bother from now on */
        mp = hw_lock_phys_vir(PPC_SID_KERNEL, va);                              /* Find mapping and lock the physical entry for this mapping */

        if((unsigned int)mp&1) {                                                                /* Did the lock on the phys entry time out? */
                splx(s);                                                                                        /* Restore 'rupts */
                panic("kvtophys: timeout obtaining lock on physical entry (vaddr=%08X)\n", va); /* Scream bloody murder! */
                return 0;
        }

        if(!mp) {                                                                                               /* If it was not a normal page */
                pa = hw_cvp_blk(kernel_pmap, va);                                       /* Try to convert odd-sized page (returns 0 if not found) */
                splx(s);                                                                                        /* Restore 'rupts */
                return pa;                                                                                      /* Return physical address */
        }

        mpv = hw_cpv(mp);                                                                               /* Convert to virtual addressing */
        
        if(!mpv->physent) {                                                                             /* Was there a physical entry? */
                pa = (vm_offset_t)((mpv->PTEr & -PAGE_SIZE) | ((unsigned int)va & (PAGE_SIZE-1)));      /* Get physical address from physent */
        }
        else {
                pa = (vm_offset_t)((mpv->physent->pte1 & -PAGE_SIZE) | ((unsigned int)va & (PAGE_SIZE-1)));     /* Get physical address from physent */
                hw_unlock_bit((unsigned int *)&mpv->physent->phys_link, PHYS_LOCK);     /* Unlock the physical entry */
        }
        
        splx(s);                                                                                                /* Restore 'rupts */
        return pa;                                                                                              /* Return the physical address... */
}

/*
 *      phystokv(addr)
 *
 *      Convert a physical address to a kernel virtual address if
 *      there is a mapping, otherwise return NULL
 */

vm_offset_t phystokv(vm_offset_t pa) {

        struct phys_entry       *pp;
        vm_offset_t                     va;

        pp = pmap_find_physentry(pa);                                                   /* Find the physical entry */
        if (PHYS_NULL == pp) {
                return (vm_offset_t)NULL;                                                       /* If none, return null */
        }
        if(!(va=mapping_p2v(kernel_pmap, pp))) {
                return 0;                                                                                       /* Can't find it, return 0... */
        }
        return (va | (pa & (PAGE_SIZE-1)));                                             /* Build and return VADDR... */

}

/*
 *              void ignore_zero_fault(boolean_t) - Sets up to ignore or honor any fault on 
 *              page 0 access for the current thread.
 *
 *              If parameter is TRUE, faults are ignored
 *              If parameter is FALSE, faults are honored
 *
 */

void ignore_zero_fault(boolean_t type) {                                /* Sets up to ignore or honor any fault on page 0 access for the current thread */

        if(type) current_act()->mact.specFlags |= ignoreZeroFault;      /* Ignore faults on page 0 */
        else     current_act()->mact.specFlags &= ~ignoreZeroFault;     /* Honor faults on page 0 */
        
        return;                                                                                         /* Return the result or 0... */
}


/*
 *      Allocates a range of virtual addresses in a map as optimally as
 *      possible for block mapping.  The start address is aligned such
 *      that a minimum number of power-of-two sized/aligned blocks is
 *      required to cover the entire range. 
 *
 *      We also use a mask of valid block sizes to determine optimality.
 *
 *      Note that the passed in pa is not actually mapped to the selected va,
 *      rather, it is used to figure the optimal boundary.  The actual 
 *      V to R mapping is done externally.
 *
 *      This function will return KERN_INVALID_ADDRESS if an optimal address 
 *      can not be found.  It is not necessarily a fatal error, the caller may still be
 *      still be able to do a non-optimal assignment.
 */

kern_return_t vm_map_block(vm_map_t map, vm_offset_t *va, vm_offset_t *bnd, vm_offset_t pa, 
        vm_size_t size, vm_prot_t prot) {

        vm_map_entry_t  entry, next, tmp_entry, new_entry;
        vm_offset_t             start, end, algnpa, endadr, strtadr, curradr;
        vm_offset_t             boundary;
        
        unsigned int    maxsize, minsize, leading, trailing;
        
        assert(page_aligned(pa));
        assert(page_aligned(size));

        if (map == VM_MAP_NULL) return(KERN_INVALID_ARGUMENT);  /* Dude, like we need a target map */
        
        minsize = blokValid ^ (blokValid & (blokValid - 1));    /* Set minimum subblock size */
        maxsize = 0x80000000 >> cntlzw(blokValid);      /* Set maximum subblock size */
        
        boundary = 0x80000000 >> cntlzw(size);          /* Get optimal boundary */
        if(boundary > maxsize) boundary = maxsize;      /* Pin this at maximum supported hardware size */
        
        vm_map_lock(map);                                                       /* No touchee no mapee */

        for(; boundary > minsize; boundary >>= 1) {     /* Try all optimizations until we find one */
                if(!(boundary & blokValid)) continue;   /* Skip unavailable block sizes */
                algnpa = (pa + boundary - 1) & -boundary;       /* Round physical up */
                leading = algnpa - pa;                                  /* Get leading size */
                
                curradr = 0;                                                    /* Start low */
                
                while(1) {                                                              /* Try all possible values for this opt level */

                        curradr = curradr + boundary;           /* Get the next optimal address */
                        strtadr = curradr - leading;            /* Calculate start of optimal range */
                        endadr = strtadr + size;                        /* And now the end */
                        
                        if((curradr < boundary) ||                      /* Did address wrap here? */
                                (strtadr > curradr) ||                  /* How about this way? */
                                (endadr < strtadr)) break;              /* We wrapped, try next lower optimization... */
                
                        if(strtadr < map->min_offset) continue; /* Jump to the next higher slot... */
                        if(endadr > map->max_offset) break;     /* No room right now... */
                        
                        if(vm_map_lookup_entry(map, strtadr, &entry)) continue; /* Find slot, continue if allocated... */
                
                        next = entry->vme_next;                         /* Get the next entry */
                        if((next == vm_map_to_entry(map)) ||    /* Are we the last entry? */
                                (next->vme_start >= endadr)) {  /* or do we end before the next entry? */
                        
                                new_entry = vm_map_entry_insert(map, entry, strtadr, endadr, /* Yes, carve out our entry */
                                        VM_OBJECT_NULL,
                                        0,                                                      /* Offset into object of 0 */
                                        FALSE,                                          /* No copy needed */
                                        FALSE,                                          /* Not shared */
                                        FALSE,                                          /* Not in transition */
                                        prot,                                           /* Set the protection to requested */
                                        prot,                                           /* We can't change protection */
                                        VM_BEHAVIOR_DEFAULT,            /* Use default behavior, but makes no never mind,
                                                                                                   'cause we don't page in this area */
                                        VM_INHERIT_DEFAULT,             /* Default inheritance */
                                        0);                                                     /* Nothing is wired */
                        
                                vm_map_unlock(map);                             /* Let the world see it all */
                                *va = strtadr;                                  /* Tell everyone */
                                *bnd = boundary;                                /* Say what boundary we are aligned to */
                                return(KERN_SUCCESS);                   /* Leave, all is right with the world... */
                        }
                }               
        }       

        vm_map_unlock(map);                                                     /* Couldn't find a slot */
        return(KERN_INVALID_ADDRESS);
}

/* 
 *              Copies data from a physical page to a virtual page.  This is used to 
 *              move data from the kernel to user state.
 *
 *              Note that it is invalid to have a source that spans a page boundry.
 *              This can block.
 *              We don't check protection either.
 *              And we don't handle a block mapped sink address either.
 *
 */
 
kern_return_t copyp2v(vm_offset_t source, vm_offset_t sink, unsigned int size) {
 
        vm_map_t map;
        kern_return_t ret;
        unsigned int spaceid;
        int left, csize;
        vm_offset_t pa;
        register mapping *mpv, *mp;
        spl_t s;

        if((size == 0) || ((source ^ (source + size - 1)) & -PAGE_SIZE)) return KERN_FAILURE;   /* We don't allow a source page crosser */
        map = current_act()->map;                                               /* Get the current map */

        while(size) {
                s=splhigh();                                                            /* Don't bother me */
        
                spaceid = map->pmap->pmapSegs[(unsigned int)sink >> 28];        /* Get space ID. Don't bother to clean top bits */

                mp = hw_lock_phys_vir(spaceid, sink);           /* Lock the physical entry for the sink */
                if(!mp) {                                                                       /* Was it there? */
                        splx(s);                                                                /* Restore the interrupt level */
                        ret = vm_fault(map, trunc_page(sink), VM_PROT_READ | VM_PROT_WRITE, FALSE, NULL, 0);    /* Didn't find it, try to fault it in... */
                        if (ret == KERN_SUCCESS) continue;              /* We got it in, try again to find it... */

                        return KERN_FAILURE;                                    /* Didn't find any, return no good... */
                }
                if((unsigned int)mp&1) {                                        /* Did we timeout? */
                        panic("dumpaddr: timeout locking physical entry for virtual address (%08X)\n", sink);   /* Yeah, scream about it! */
                        splx(s);                                                                /* Restore the interrupt level */
                        return KERN_FAILURE;                                    /* Bad hair day, return FALSE... */
                }

                mpv = hw_cpv(mp);                                                       /* Convert mapping block to virtual */

                if(mpv->PTEr & 1) {                                                     /* Are we write protected? yes, could indicate COW */
                        hw_unlock_bit((unsigned int *)&mpv->physent->phys_link, PHYS_LOCK);     /* Unlock the sink */
                        splx(s);                                                                /* Restore the interrupt level */
                        ret = vm_fault(map, trunc_page(sink), VM_PROT_READ | VM_PROT_WRITE, FALSE, NULL, 0);    /* check for a COW area */
                        if (ret == KERN_SUCCESS) continue;              /* We got it in, try again to find it... */
                        return KERN_FAILURE;                                    /* Didn't find any, return no good... */
                }
                left = PAGE_SIZE - (sink & PAGE_MASK);          /* Get amount left on sink page */

                csize = size < left ? size : left;              /* Set amount to copy this pass */

                pa = (vm_offset_t)((mpv->physent->pte1 & ~PAGE_MASK) | ((unsigned int)sink & PAGE_MASK));       /* Get physical address of sink */

                bcopy_physvir((char *)source, (char *)pa, csize);       /* Do a physical copy, virtually */

                hw_set_mod(mpv->physent);                                       /* Go set the change of the sink */

                hw_unlock_bit((unsigned int *)&mpv->physent->phys_link, PHYS_LOCK);     /* Unlock the sink */
                splx(s);                                                                        /* Open up for interrupts */

                sink += csize;                                                          /* Move up to start of next page */
                source += csize;                                                        /* Move up source */
                size -= csize;                                                          /* Set amount for next pass */
        }
        return KERN_SUCCESS;
}


/*
 * copy 'size' bytes from physical to physical address
 * the caller must validate the physical ranges 
 *
 * if flush_action == 0, no cache flush necessary
 * if flush_action == 1, flush the source
 * if flush_action == 2, flush the dest
 * if flush_action == 3, flush both source and dest
 */

kern_return_t copyp2p(vm_offset_t source, vm_offset_t dest, unsigned int size, unsigned int flush_action) {

        switch(flush_action) {
        case 1:
                flush_dcache(source, size, 1);
                break;
        case 2:
                flush_dcache(dest, size, 1);
                break;
        case 3:
                flush_dcache(source, size, 1);
                flush_dcache(dest, size, 1);
                break;

        }
        bcopy_phys((char *)source, (char *)dest, size); /* Do a physical copy */

        switch(flush_action) {
        case 1:
                flush_dcache(source, size, 1);
                break;
        case 2:
                flush_dcache(dest, size, 1);
                break;
        case 3:
                flush_dcache(source, size, 1);
                flush_dcache(dest, size, 1);
                break;

        }
}



#if DEBUG
/*
 *              Dumps out the mapping stuff associated with a virtual address
 */
void dumpaddr(space_t space, vm_offset_t va) {

        mapping         *mp, *mpv;
        vm_offset_t     pa;
        spl_t           s;

        s=splhigh();                                                                                    /* Don't bother me */

        mp = hw_lock_phys_vir(space, va);                                               /* Lock the physical entry for this mapping */
        if(!mp) {                                                                                               /* Did we find one? */
                splx(s);                                                                                        /* Restore the interrupt level */
                printf("dumpaddr: virtual address (%08X) not mapped\n", va);    
                return;                                                                                         /* Didn't find any, return FALSE... */
        }
        if((unsigned int)mp&1) {                                                                /* Did we timeout? */
                panic("dumpaddr: timeout locking physical entry for virtual address (%08X)\n", va);     /* Yeah, scream about it! */
                splx(s);                                                                                        /* Restore the interrupt level */
                return;                                                                                         /* Bad hair day, return FALSE... */
        }
        printf("dumpaddr: space=%08X; vaddr=%08X\n", space, va);        /* Say what address were dumping */
        mpv = hw_cpv(mp);                                                                               /* Get virtual address of mapping */
        dumpmapping(mpv);
        if(mpv->physent) {
                dumppca(mpv);
                hw_unlock_bit((unsigned int *)&mpv->physent->phys_link, PHYS_LOCK);     /* Unlock physical entry associated with mapping */
        }
        splx(s);                                                                                                /* Was there something you needed? */
        return;                                                                                                 /* Tell them we did it */
}



/*
 *              Prints out a mapping control block
 *
 */
 
void dumpmapping(struct mapping *mp) {                                          /* Dump out a mapping */

        printf("Dump of mapping block: %08X\n", mp);                    /* Header */
        printf("                 next: %08X\n", mp->next);                 
        printf("             hashnext: %08X\n", mp->hashnext);                 
        printf("              PTEhash: %08X\n", mp->PTEhash);                 
        printf("               PTEent: %08X\n", mp->PTEent);                 
        printf("              physent: %08X\n", mp->physent);                 
        printf("                 PTEv: %08X\n", mp->PTEv);                 
        printf("                 PTEr: %08X\n", mp->PTEr);                 
        printf("                 pmap: %08X\n", mp->pmap);
        
        if(mp->physent) {                                                                       /* Print physent if it exists */
                printf("Associated physical entry: %08X %08X\n", mp->physent->phys_link, mp->physent->pte1);
        }
        else {
                printf("Associated physical entry: none\n");
        }
        
        dumppca(mp);                                                                            /* Dump out the PCA information */
        
        return;
}

/*
 *              Prints out a PTEG control area
 *
 */
 
void dumppca(struct mapping *mp) {                                              /* PCA */

        PCA                             *pca;
        unsigned int    *pteg;
        
        pca = (PCA *)((unsigned int)mp->PTEhash&-64);           /* Back up to the start of the PCA */
        pteg=(unsigned int *)((unsigned int)pca-(((hash_table_base&0x0000FFFF)+1)<<16));
        printf(" Dump of PCA: %08X\n", pca);            /* Header */
        printf("     PCAlock: %08X\n", pca->PCAlock);                 
        printf("     PCAallo: %08X\n", pca->flgs.PCAallo);                 
        printf("     PCAhash: %08X %08X %08X %08X\n", pca->PCAhash[0], pca->PCAhash[1], pca->PCAhash[2], pca->PCAhash[3]);                 
        printf("              %08X %08X %08X %08X\n", pca->PCAhash[4], pca->PCAhash[5], pca->PCAhash[6], pca->PCAhash[7]);                 
        printf("Dump of PTEG: %08X\n", pteg);           /* Header */
        printf("              %08X %08X %08X %08X\n", pteg[0], pteg[1], pteg[2], pteg[3]);                 
        printf("              %08X %08X %08X %08X\n", pteg[4], pteg[5], pteg[6], pteg[7]);                 
        printf("              %08X %08X %08X %08X\n", pteg[8], pteg[9], pteg[10], pteg[11]);                 
        printf("              %08X %08X %08X %08X\n", pteg[12], pteg[13], pteg[14], pteg[15]);                 
        return;
}

/*
 *              Dumps starting with a physical entry
 */
 
void dumpphys(struct phys_entry *pp) {                                          /* Dump from physent */

        mapping                 *mp;
        PCA                             *pca;
        unsigned int    *pteg;

        printf("Dump from physical entry %08X: %08X %08X\n", pp, pp->phys_link, pp->pte1);
        mp = hw_cpv(pp->phys_link);
        while(mp) {
                dumpmapping(mp);
                dumppca(mp);
                mp = hw_cpv(mp->next);
        }
        
        return;
}

#endif


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

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

kern_return_t bmapmap(vm_offset_t va, vm_offset_t pa, vm_size_t size, vm_prot_t prot, int attr);
kern_return_t bmapmap(vm_offset_t va, vm_offset_t pa, vm_size_t size, vm_prot_t prot, int attr) {
        
        pmap_map_block(current_act()->task->map->pmap, va, pa, size, prot, attr, 0);    /* Map it in */
        return KERN_SUCCESS;
}

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