xnu-792.10.96.tar.gz

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

/*
 * Copyright (c) 2000-2005 Apple Computer, Inc. All rights reserved.
 *
 * @APPLE_LICENSE_HEADER_START@
 * 
 * The contents of this file constitute Original Code as defined in and
 * are subject to the Apple Public Source License Version 1.1 (the
 * "License").  You may not use this file except in compliance with the
 * License.  Please obtain a copy of the License at
 * http://www.apple.com/publicsource and read it before using this file.
 * 
 * This Original Code and all software distributed under the License are
 * distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, EITHER
 * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
 * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT.  Please see the
 * License for the specific language governing rights and limitations
 * under the License.
 * 
 * @APPLE_LICENSE_HEADER_END@
 */
/*
 * @OSF_COPYRIGHT@
 */
/*
 * Mach Operating System
 * Copyright (c) 1990,1991,1992 The University of Utah and
 * the Center for Software Science (CSS).
 * Copyright (c) 1991,1987 Carnegie Mellon University.
 * All rights reserved.
 *
 * Permission to use, copy, modify and distribute this software and its
 * documentation is hereby granted, provided that both the copyright
 * notice and this permission notice appear in all copies of the
 * software, derivative works or modified versions, and any portions
 * thereof, and that both notices appear in supporting documentation,
 * and that all advertising materials mentioning features or use of
 * this software display the following acknowledgement: ``This product
 * includes software developed by the Center for Software Science at
 * the University of Utah.''
 *
 * CARNEGIE MELLON, THE UNIVERSITY OF UTAH AND CSS ALLOW FREE USE OF
 * THIS SOFTWARE IN ITS "AS IS" CONDITION, AND DISCLAIM ANY LIABILITY
 * OF ANY KIND FOR ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF
 * THIS SOFTWARE.
 *
 * CSS requests users of this software to return to css-dist@cs.utah.edu any
 * improvements that they make and grant CSS redistribution rights.
 *
 * Carnegie Mellon requests users of this software to return to
 *  Software Distribution Coordinator  or  Software.Distribution@CS.CMU.EDU
 *  School of Computer Science
 *  Carnegie Mellon University
 *  Pittsburgh PA 15213-3890
 * any improvements or extensions that they make and grant Carnegie Mellon
 * the rights to redistribute these changes.
 *
 *      Utah $Hdr: pmap.c 1.28 92/06/23$
 *      Author: Mike Hibler, Bob Wheeler, University of Utah CSS, 10/90
 */
 
/*
 *      Manages physical address maps for powerpc.
 *
 *      In addition to hardware address maps, this
 *      module is called upon to provide software-use-only
 *      maps which may or may not be stored in the same
 *      form as hardware maps.  These pseudo-maps are
 *      used to store intermediate results from copy
 *      operations to and from address spaces.
 *
 *      Since the information managed by this module is
 *      also stored by the logical address mapping module,
 *      this module may throw away valid virtual-to-physical
 *      mappings at almost any time.  However, invalidations
 *      of virtual-to-physical mappings must be done as
 *      requested.
 *
 *      In order to cope with hardware architectures which
 *      make virtual-to-physical map invalidates expensive,
 *      this module may delay invalidate or reduced protection
 *      operations until such time as they are actually
 *      necessary.  This module is given full information to
 *      when physical maps must be made correct.
 *      
 */

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

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

#include <ppc/pmap.h>
#include <ppc/mem.h>
#include <ppc/mappings.h>

#include <ppc/new_screen.h>
#include <ppc/Firmware.h>
#include <ppc/savearea.h>
#include <ppc/cpu_internal.h>
#include <ppc/exception.h>
#include <ppc/low_trace.h>
#include <ppc/lowglobals.h>
#include <ddb/db_output.h>
#include <machine/cpu_capabilities.h>

#include <vm/vm_protos.h> /* must be last */


extern unsigned int     avail_remaining;
unsigned int    debugbackpocket;                                                        /* (TEST/DEBUG) */

vm_offset_t             first_free_virt;
int             current_free_region;                                            /* Used in pmap_next_page */

pmapTransTab *pmapTrans;                                                                        /* Point to the hash to pmap translations */
struct phys_entry *phys_table;

/* forward */
static void pmap_map_physical(void);
static void pmap_map_iohole(addr64_t paddr, addr64_t size);
void pmap_activate(pmap_t pmap, thread_t th, int which_cpu);
void pmap_deactivate(pmap_t pmap, thread_t th, int which_cpu);

extern void hw_hash_init(void);

/*  NOTE:  kernel_pmap_store must be in V=R storage and aligned!!!!!!!!!!!!!! */

extern struct pmap      kernel_pmap_store;
pmap_t          kernel_pmap;                    /* Pointer to kernel pmap and anchor for in-use pmaps */                
addr64_t        kernel_pmap_phys;               /* Pointer to kernel pmap and anchor for in-use pmaps, physical address */              
pmap_t          cursor_pmap;                    /* Pointer to last pmap allocated or previous if removed from in-use list */
pmap_t          sharedPmap;                             /* Pointer to common pmap for 64-bit address spaces */
struct zone     *pmap_zone;                             /* zone of pmap structures */
boolean_t       pmap_initialized = FALSE;

int ppc_max_pmaps;                                      /* Maximum number of concurrent address spaces allowed. This is machine dependent */    
addr64_t vm_max_address;                        /* Maximum effective address supported */
addr64_t vm_max_physical;                       /* Maximum physical address supported */

/*
 * Physical-to-virtual translations are handled by inverted page table
 * structures, phys_tables.  Multiple mappings of a single page are handled
 * by linking the affected mapping structures. We initialise one region
 * for phys_tables of the physical memory we know about, but more may be
 * added as it is discovered (eg. by drivers).
 */

/*
 *      free pmap list. caches the first free_pmap_max pmaps that are freed up
 */
int             free_pmap_max = 32;
int             free_pmap_count;
pmap_t  free_pmap_list;
decl_simple_lock_data(,free_pmap_lock)

/*
 * Function to get index into phys_table for a given physical address
 */

struct phys_entry *pmap_find_physentry(ppnum_t pa)
{
        int i;
        unsigned int entry;

        for (i = pmap_mem_regions_count - 1; i >= 0; i--) {
                if (pa < pmap_mem_regions[i].mrStart) continue; /* See if we fit in this region */
                if (pa > pmap_mem_regions[i].mrEnd) continue;   /* Check the end too */
                
                entry = (unsigned int)pmap_mem_regions[i].mrPhysTab + ((pa - pmap_mem_regions[i].mrStart) * sizeof(phys_entry_t));
                return (struct phys_entry *)entry;
        }
//      kprintf("DEBUG - pmap_find_physentry: page 0x%08X not found\n", pa);
        return 0;
}

/*
 * kern_return_t
 * pmap_add_physical_memory(vm_offset_t spa, vm_offset_t epa,
 *                          boolean_t available, unsigned int attr)
 *
 *      THIS IS NOT SUPPORTED
 */
kern_return_t
pmap_add_physical_memory(
        __unused vm_offset_t spa, 
        __unused vm_offset_t epa,
        __unused boolean_t available,
        __unused unsigned int attr)
{
        
        panic("Forget it! You can't map no more memory, you greedy puke!\n");
        return KERN_SUCCESS;
}

/*
 * pmap_map(va, spa, epa, prot)
 *      is called during boot to map memory in the kernel's address map.
 *      A virtual address range starting at "va" is mapped to the physical
 *      address range "spa" to "epa" with machine independent protection
 *      "prot".
 *
 *      "va", "spa", and "epa" are byte addresses and must be on machine
 *      independent page boundaries.
 *
 *      Pages with a contiguous virtual address range, the same protection, and attributes.
 *      therefore, we map it with a single block.
 *
 *      Note that this call will only map into 32-bit space
 *
 */

vm_offset_t
pmap_map(
        vm_offset_t va,
        vm_offset_t spa,
        vm_offset_t epa,
        vm_prot_t prot,
        unsigned int flags)
{
        unsigned int mflags;
        mflags = 0;                                                                             /* Make sure this is initialized to nothing special */
        if(!(flags & VM_WIMG_USE_DEFAULT)) {                    /* Are they supplying the attributes? */
                mflags = mmFlgUseAttr | (flags & VM_MEM_GUARDED) | ((flags & VM_MEM_NOT_CACHEABLE) >> 1);       /* Convert to our mapping_make flags */
        }

        addr64_t colladr;
        
        if (spa == epa) return(va);

        assert(epa > spa);

        colladr = mapping_make(kernel_pmap, (addr64_t)va, (ppnum_t)(spa >> 12),
                               (mmFlgBlock | mmFlgPerm), (epa - spa) >> 12, (prot & VM_PROT_ALL) );

        if(colladr) {                                                                                   /* Was something already mapped in the range? */
                panic("pmap_map: attempt to map previously mapped range - va = %08X, pa = %08X, epa = %08X, collision = %016llX\n",
                        va, spa, epa, colladr);
        }                               
        return(va);
}

/*
 * pmap_map_physical()
 *      Maps physical memory into the kernel's address map beginning at lgPMWvaddr, the
 *  physical memory window.
 *
 */
void
pmap_map_physical()
{
        unsigned region;
        uint64_t msize, size;
        addr64_t paddr, vaddr, colladdr;

        /* Iterate over physical memory regions, block mapping each into the kernel's address map */    
        for (region = 0; region < (unsigned)pmap_mem_regions_count; region++) {
                paddr = ((addr64_t)pmap_mem_regions[region].mrStart << 12);     /* Get starting physical address */
                size  = (((addr64_t)pmap_mem_regions[region].mrEnd + 1) << 12) - paddr;

                vaddr = paddr + lowGlo.lgPMWvaddr;                                      /* Get starting virtual address */

                while (size > 0) {
                        
                        msize = ((size > 0x0000020000000000ULL) ? 0x0000020000000000ULL : size);        /* Get size, but no more than 2TBs */
                        
                        colladdr = mapping_make(kernel_pmap, vaddr, (paddr >> 12),
                                (mmFlgBlock | mmFlgPerm), (msize >> 12),
                                (VM_PROT_READ | VM_PROT_WRITE));
                        if (colladdr) {
                                panic ("pmap_map_physical: mapping failure - va = %016llX, pa = %08X, size = %08X, collision = %016llX\n",
                                           vaddr, (paddr >> 12), (msize >> 12), colladdr);
                        }

                        vaddr = vaddr + (uint64_t)msize;                                /* Point to the next virtual addr */
                        paddr = paddr + (uint64_t)msize;                                /* Point to the next physical addr */
                        size  -= msize;
                }
        }
}

/*
 * pmap_map_iohole(addr64_t paddr, addr64_t size)
 *      Maps an I/O hole into the kernel's address map at its proper offset in
 *      the physical memory window.
 *
 */
void
pmap_map_iohole(addr64_t paddr, addr64_t size)
{

        addr64_t vaddr, colladdr, msize;
        uint32_t psize;

        vaddr = paddr + lowGlo.lgPMWvaddr;                                              /* Get starting virtual address */              

        while (size > 0) {

                msize = ((size > 0x0000020000000000ULL) ? 0x0000020000000000ULL : size);        /* Get size, but no more than 2TBs */
                
                colladdr = mapping_make(kernel_pmap, vaddr, (paddr >> 12),
                        (mmFlgBlock | mmFlgPerm | mmFlgGuarded | mmFlgCInhib), (msize >> 12),
                        (VM_PROT_READ | VM_PROT_WRITE));
                if (colladdr) {
                        panic ("pmap_map_iohole: mapping failed - va = %016llX, pa = %08X, size = %08X, collision = %016llX\n",
                                   vaddr, (paddr >> 12), (msize >> 12), colladdr);
                }

                vaddr = vaddr + (uint64_t)msize;                                        /* Point to the next virtual addr */
                paddr = paddr + (uint64_t)msize;                                        /* Point to the next physical addr */
                size  -= msize;
        }       
}

/*
 *      Bootstrap the system enough to run with virtual memory.
 *      Map the kernel's code and data, and allocate the system page table.
 *      Called with mapping done by BATs. Page_size must already be set.
 *
 *      Parameters:
 *      msize:  Total memory present
 *      first_avail:    First virtual address available
 *      kmapsize:       Size of kernel text and data
 */
void
pmap_bootstrap(uint64_t msize, vm_offset_t *first_avail, unsigned int kmapsize)
{
        vm_offset_t     addr;
        vm_size_t               size;
        unsigned int    i, num, mapsize, vmpagesz, vmmapsz, nbits;
        signed                  bank;
        uint64_t                tmemsize;
        uint_t                  htslop;
        vm_offset_t             first_used_addr, PCAsize;
        struct phys_entry *phys_entry;

        *first_avail = round_page(*first_avail);                                /* Make sure we start out on a page boundary */
        vm_last_addr = VM_MAX_KERNEL_ADDRESS;                                   /* Set the highest address know to VM */

        /*
         * Initialize kernel pmap
         */
        kernel_pmap = &kernel_pmap_store;
        kernel_pmap_phys = (addr64_t)&kernel_pmap_store;
        cursor_pmap = &kernel_pmap_store;

        kernel_pmap->pmap_link.next = (queue_t)kernel_pmap;             /* Set up anchor forward */
        kernel_pmap->pmap_link.prev = (queue_t)kernel_pmap;             /* Set up anchor reverse */
        kernel_pmap->ref_count = 1;
        kernel_pmap->pmapFlags = pmapKeyDef;                                    /* Set the default keys */
        kernel_pmap->pmapFlags |= pmapNXdisabled;
        kernel_pmap->pmapCCtl = pmapCCtlVal;                                    /* Initialize cache control */
        kernel_pmap->space = PPC_SID_KERNEL;
        kernel_pmap->pmapvr = 0;                                                                /* Virtual = Real  */

/*
 *  IBM's recommended hash table size is one PTEG for every 2 physical pages.
 *  However, we have found that OSX rarely uses more than 4 PTEs in a PTEG
 *  with this size table.  Therefore, by default we allocate a hash table
 *  one half IBM's recommended size, ie one PTEG per 4 pages.  The "ht_shift" boot-arg
 *  can be used to override the default hash table size.
 *      We will allocate the hash table in physical RAM, outside of kernel virtual memory,
 *      at the top of the highest bank that will contain it.
 *      Note that "bank" doesn't refer to a physical memory slot here, it is a range of
 *      physically contiguous memory.
 *
 *      The PCA will go there as well, immediately before the hash table.
 */
 
        nbits = cntlzw(((msize << 1) - 1) >> 32);                               /* Get first bit in upper half */
        if (nbits == 32)                                        /* If upper half was empty, find bit in bottom half */
        nbits = nbits + cntlzw((uint_t)((msize << 1) - 1));
        tmemsize = 0x8000000000000000ULL >> nbits;              /* Get memory size rounded up to power of 2 */
        
    /* Calculate hash table size:  First, make sure we don't overflow 32-bit arithmetic. */
        if (tmemsize > 0x0000002000000000ULL)
        tmemsize = 0x0000002000000000ULL;

    /* Second, calculate IBM recommended hash table size, ie one PTEG per 2 physical pages */
        hash_table_size = (uint_t)(tmemsize >> 13) * PerProcTable[0].ppe_vaddr->pf.pfPTEG;
    
    /* Third, cut this in half to produce the OSX default, ie one PTEG per 4 physical pages */
    hash_table_size >>= 1;
    
    /* Fourth, adjust default size per "ht_shift" boot arg */
    if (hash_table_shift >= 0)                              /* if positive, make size bigger */
        hash_table_size <<= hash_table_shift;
    else                                                    /* if "ht_shift" is negative, make smaller */
        hash_table_size >>= (-hash_table_shift);
    
    /* Fifth, make sure we are at least minimum size */
        if (hash_table_size < (256 * 1024))
        hash_table_size = (256 * 1024);

        while(1) {                                                                                              /* Try to fit hash table in PCA into contiguous memory */

                if(hash_table_size < (256 * 1024)) {                            /* Have we dropped too short? This should never, ever happen */
                        panic("pmap_bootstrap: Can't find space for hash table\n");     /* This will never print, system isn't up far enough... */
                }

                PCAsize = (hash_table_size / PerProcTable[0].ppe_vaddr->pf.pfPTEG) * sizeof(PCA_t);     /* Get total size of PCA table */
                PCAsize = round_page(PCAsize);                                  /* Make sure it is at least a page long */
        
                for(bank = pmap_mem_regions_count - 1; bank >= 0; bank--) {     /* Search backwards through banks */
                        
                        hash_table_base = ((addr64_t)pmap_mem_regions[bank].mrEnd << 12) - hash_table_size + PAGE_SIZE; /* Get tenative address */
                        
                        htslop = hash_table_base & (hash_table_size - 1);       /* Get the extra that we will round down when we align */
                        hash_table_base = hash_table_base & -(addr64_t)hash_table_size; /* Round down to correct boundary */
                        
                        if((hash_table_base - round_page(PCAsize)) >= ((addr64_t)pmap_mem_regions[bank].mrStart << 12)) break;  /* Leave if we fit */
                }
                
                if(bank >= 0) break;                                                            /* We are done if we found a suitable bank */
                
                hash_table_size = hash_table_size >> 1;                         /* Try the next size down */
        }

        if(htslop) {                                                                                    /* If there was slop (i.e., wasted pages for alignment) add a new region */
                for(i = pmap_mem_regions_count - 1; i >= (unsigned)bank; i--) { /* Copy from end to our bank, including our bank */
                        pmap_mem_regions[i + 1].mrStart  = pmap_mem_regions[i].mrStart; /* Set the start of the bank */
                        pmap_mem_regions[i + 1].mrAStart = pmap_mem_regions[i].mrAStart;        /* Set the start of allocatable area */
                        pmap_mem_regions[i + 1].mrEnd    = pmap_mem_regions[i].mrEnd;   /* Set the end address of bank */
                        pmap_mem_regions[i + 1].mrAEnd   = pmap_mem_regions[i].mrAEnd;  /* Set the end address of allocatable area */
                }
                
                pmap_mem_regions[i + 1].mrStart  = (hash_table_base + hash_table_size) >> 12;   /* Set the start of the next bank to the start of the slop area */
                pmap_mem_regions[i + 1].mrAStart = (hash_table_base + hash_table_size) >> 12;   /* Set the start of allocatable area to the start of the slop area */
                pmap_mem_regions[i].mrEnd        = (hash_table_base + hash_table_size - 4096) >> 12;    /* Set the end of our bank to the end of the hash table */
                
        }               
        
        pmap_mem_regions[bank].mrAEnd = (hash_table_base - PCAsize - 4096) >> 12;       /* Set the maximum allocatable in this bank */
        
        hw_hash_init();                                                                                 /* Initiaize the hash table and PCA */
        hw_setup_trans();                                                                               /* Set up hardware registers needed for translation */
        
/*
 *      The hash table is now all initialized and so is the PCA.  Go on to do the rest of it.
 *      This allocation is from the bottom up.
 */     
        
        num = atop_64(msize);                                                                           /* Get number of pages in all of memory */

/* Figure out how much we need to allocate */

        size = (vm_size_t) (
                (InitialSaveBloks * PAGE_SIZE) +                                        /* Allow space for the initial context saveareas */
                (BackPocketSaveBloks * PAGE_SIZE) +                                     /* For backpocket saveareas */
                trcWork.traceSize +                                                             /* Size of trace table */
                ((((1 << maxAdrSpb) * sizeof(pmapTransTab)) + 4095) & -4096) +  /* Size of pmap translate table */
                (((num * sizeof(struct phys_entry)) + 4095) & -4096)    /* For the physical entries */
        );

        mapsize = size = round_page(size);                                              /* Get size of area to map that we just calculated */
        mapsize = mapsize + kmapsize;                                                   /* Account for the kernel text size */

        vmpagesz = round_page(num * sizeof(struct vm_page));    /* Allow for all vm_pages needed to map physical mem */
        vmmapsz = round_page((num / 8) * sizeof(struct vm_map_entry));  /* Allow for vm_maps */
        
        mapsize = mapsize + vmpagesz + vmmapsz;                                 /* Add the VM system estimates into the grand total */

        mapsize = mapsize + (4 * 1024 * 1024);                                  /* Allow for 4 meg of extra mappings */
        mapsize = ((mapsize / PAGE_SIZE) + MAPPERBLOK - 1) / MAPPERBLOK;        /* Get number of blocks of mappings we need */
        mapsize = mapsize + ((mapsize  + MAPPERBLOK - 1) / MAPPERBLOK); /* Account for the mappings themselves */

        size = size + (mapsize * PAGE_SIZE);                                    /* Get the true size we need */

        /* hash table must be aligned to its size */

        addr = *first_avail;                                                                    /* Set the address to start allocations */
        first_used_addr = addr;                                                                 /* Remember where we started */

        bzero((char *)addr, size);                                                              /* Clear everything that we are allocating */

        savearea_init(addr);                                                                    /* Initialize the savearea chains and data */

        addr = (vm_offset_t)((unsigned int)addr + ((InitialSaveBloks + BackPocketSaveBloks) * PAGE_SIZE));      /* Point past saveareas */

        trcWork.traceCurr = (unsigned int)addr;                                 /* Set first trace slot to use */
        trcWork.traceStart = (unsigned int)addr;                                /* Set start of trace table */
        trcWork.traceEnd = (unsigned int)addr + trcWork.traceSize;              /* Set end of trace table */

        addr = (vm_offset_t)trcWork.traceEnd;                                   /* Set next allocatable location */
                
        pmapTrans = (pmapTransTab *)addr;                                               /* Point to the pmap to hash translation table */
                
        pmapTrans[PPC_SID_KERNEL].pmapPAddr = (addr64_t)((uintptr_t)kernel_pmap);       /* Initialize the kernel pmap in the translate table */
        pmapTrans[PPC_SID_KERNEL].pmapVAddr = CAST_DOWN(unsigned int, kernel_pmap);  /* Initialize the kernel pmap in the translate table */
                
        addr += ((((1 << maxAdrSpb) * sizeof(pmapTransTab)) + 4095) & -4096);   /* Point past pmap translate table */

/*      NOTE: the phys_table must be within the first 2GB of physical RAM. This makes sure we only need to do 32-bit arithmetic */

        phys_entry = (struct phys_entry *) addr;                                /* Get pointer to physical table */

        for (bank = 0; bank < pmap_mem_regions_count; bank++) { /* Set pointer and initialize all banks of ram */
                
                pmap_mem_regions[bank].mrPhysTab = phys_entry;          /* Set pointer to the physical table for this bank */
                
                phys_entry = phys_entry + (pmap_mem_regions[bank].mrEnd - pmap_mem_regions[bank].mrStart + 1);  /* Point to the next */
        }

        addr += (((num * sizeof(struct phys_entry)) + 4095) & -4096);   /* Step on past the physical entries */
        
/*
 *              Remaining space is for mapping entries.  Tell the initializer routine that
 *              the mapping system can't release this block because it's permanently assigned
 */

        mapping_init();                                                                                 /* Initialize the mapping tables */

        for(i = addr; i < first_used_addr + size; i += PAGE_SIZE) {     /* Add initial mapping blocks */
                mapping_free_init(i, 1, 0);                                                     /* Pass block address and say that this one is not releasable */
        }
        mapCtl.mapcmin = MAPPERBLOK;                                                    /* Make sure we only adjust one at a time */

        /* Map V=R the page tables */
        pmap_map(first_used_addr, first_used_addr,
                 round_page(first_used_addr + size), VM_PROT_READ | VM_PROT_WRITE, VM_WIMG_USE_DEFAULT);

        *first_avail = round_page(first_used_addr + size);              /* Set next available page */
        first_free_virt = *first_avail;                                                 /* Ditto */
        
        /* For 64-bit machines, block map physical memory and the I/O hole into kernel space */
        if(BootProcInfo.pf.Available & pf64Bit) {                               /* Are we on a 64-bit machine? */
                lowGlo.lgPMWvaddr = PHYS_MEM_WINDOW_VADDR;                      /* Initialize the physical memory window's virtual address */

                pmap_map_physical();                                                            /* Block map physical memory into the window */
                
                pmap_map_iohole(IO_MEM_WINDOW_VADDR, IO_MEM_WINDOW_SIZE);
                                                                                                                        /* Block map the I/O hole */
        }

        /* All the rest of memory is free - add it to the free
         * regions so that it can be allocated by pmap_steal
         */

        pmap_mem_regions[0].mrAStart = (*first_avail >> 12);    /* Set up the free area to start allocations (always in the first bank) */

        current_free_region = 0;                                                                /* Set that we will start allocating in bank 0 */
        avail_remaining = 0;                                                                    /* Clear free page count */
        for(bank = 0; bank < pmap_mem_regions_count; bank++) {  /* Total up all of the pages in the system that are available */
                avail_remaining += (pmap_mem_regions[bank].mrAEnd - pmap_mem_regions[bank].mrAStart) + 1;       /* Add in allocatable pages in this bank */
        }


}

/*
 * pmap_init(spa, epa)
 *      finishes the initialization of the pmap module.
 *      This procedure is called from vm_mem_init() in vm/vm_init.c
 *      to initialize any remaining data structures that the pmap module
 *      needs to map virtual memory (VM is already ON).
 *
 *      Note that the pmap needs to be sized and aligned to
 *      a power of two.  This is because it is used both in virtual and
 *      real so it can't span a page boundary.
 */

void
pmap_init(void)
{

        pmap_zone = zinit(pmapSize, 400 * pmapSize, 4096, "pmap");
#if     ZONE_DEBUG
        zone_debug_disable(pmap_zone);          /* Can't debug this one 'cause it messes with size and alignment */
#endif  /* ZONE_DEBUG */

        pmap_initialized = TRUE;

        /*
         *      Initialize list of freed up pmaps
         */
        free_pmap_list = 0;                                     /* Set that there are no free pmaps */
        free_pmap_count = 0;
        simple_lock_init(&free_pmap_lock, 0);
        
}

unsigned int pmap_free_pages(void)
{
        return avail_remaining;
}

/*
 *      This function allocates physical pages.
 */

/* Non-optimal, but only used for virtual memory startup.
 * Allocate memory from a table of free physical addresses
 * If there are no more free entries, too bad. 
 */

boolean_t pmap_next_page(ppnum_t *addrp)
{
                int i;

        if(current_free_region >= pmap_mem_regions_count) return FALSE; /* Return failure if we have used everything... */
        
        for(i = current_free_region; i < pmap_mem_regions_count; i++) { /* Find the next bank with free pages */
                if(pmap_mem_regions[i].mrAStart <= pmap_mem_regions[i].mrAEnd) break;   /* Found one */
        }
        
        current_free_region = i;                                                                                /* Set our current bank */
        if(i >= pmap_mem_regions_count) return FALSE;                                   /* Couldn't find a free page */

        *addrp = pmap_mem_regions[i].mrAStart;                                  /* Allocate the page */
        pmap_mem_regions[i].mrAStart = pmap_mem_regions[i].mrAStart + 1;        /* Set the next one to go */
        avail_remaining--;                                                                                              /* Drop free count */

        return TRUE;
}

void pmap_virtual_space(
        vm_offset_t *startp,
        vm_offset_t *endp)
{
        *startp = round_page(first_free_virt);
        *endp   = vm_last_addr;
}

/*
 * pmap_create
 *
 * Create and return a physical map.
 *
 * If the size specified for the map is zero, the map is an actual physical
 * map, and may be referenced by the hardware.
 *
 * A pmap is either in the free list or in the in-use list.  The only use
 * of the in-use list (aside from debugging) is to handle the VSID wrap situation.
 * Whenever a new pmap is allocated (i.e., not recovered from the free list). The
 * in-use list is matched until a hole in the VSID sequence is found. (Note
 * that the in-use pmaps are queued in VSID sequence order.) This is all done
 * while free_pmap_lock is held.
 *
 * If the size specified is non-zero, the map will be used in software 
 * only, and is bounded by that size.
 */
pmap_t
pmap_create(vm_map_size_t size, __unused boolean_t is_64bit)
{
        pmap_t pmap, ckpmap, fore;
        int s;
        unsigned int currSID;
        addr64_t physpmap;

        /*
         * A software use-only map doesn't even need a pmap structure.
         */
        if (size)
                return(PMAP_NULL);

        /* 
         * If there is a pmap in the pmap free list, reuse it. 
         * Note that we use free_pmap_list for all chaining of pmaps, both to
         * the free list and the in use chain (anchored from kernel_pmap).
         */
        s = splhigh();
        simple_lock(&free_pmap_lock);
        
        if(free_pmap_list) {                                                    /* Any free? */
                pmap = free_pmap_list;                                          /* Yes, allocate it */
                free_pmap_list = (pmap_t)pmap->freepmap;        /* Dequeue this one (we chain free ones through freepmap) */
                free_pmap_count--;
        }
        else {
                simple_unlock(&free_pmap_lock);                         /* Unlock just in case */
                splx(s);

                pmap = (pmap_t) zalloc(pmap_zone);                      /* Get one */
                if (pmap == PMAP_NULL) return(PMAP_NULL);       /* Handle out-of-memory condition */
                
                bzero((char *)pmap, pmapSize);                          /* Clean up the pmap */
                
                s = splhigh();
                simple_lock(&free_pmap_lock);                           /* Lock it back up      */
                
                ckpmap = cursor_pmap;                                           /* Get starting point for free ID search */
                currSID = ckpmap->spaceNum;                                     /* Get the actual space ID number */

                while(1) {                                                                      /* Keep trying until something happens */
                
                        currSID = (currSID + 1) & (maxAdrSp - 1);       /* Get the next in the sequence */
                        if(((currSID * incrVSID) & (maxAdrSp - 1)) == invalSpace) continue;     /* Skip the space we have reserved */
                        ckpmap = (pmap_t)ckpmap->pmap_link.next;        /* On to the next in-use pmap */
        
                        if(ckpmap->spaceNum != currSID) break;  /* If we are out of sequence, this is free */
                        
                        if(ckpmap == cursor_pmap) {                             /* See if we have 2^20 already allocated */
                                panic("pmap_create: Maximum number (%d) active address spaces reached\n", maxAdrSp);    /* Die pig dog */
                        }
                }

                pmap->space = (currSID * incrVSID) & (maxAdrSp - 1);    /* Calculate the actual VSID */
                pmap->spaceNum = currSID;                                       /* Set the space ID number */
/*
 *              Now we link into the chain just before the out of sequence guy.
 */

                fore = (pmap_t)ckpmap->pmap_link.prev;          /* Get the current's previous */
                pmap->pmap_link.next = (queue_t)ckpmap;         /* My next points to the current */
                fore->pmap_link.next = (queue_t)pmap;           /* Current's previous's next points to me */
                pmap->pmap_link.prev = (queue_t)fore;           /* My prev points to what the current pointed to */
                ckpmap->pmap_link.prev = (queue_t)pmap;         /* Current's prev points to me */
                
                physpmap = ((addr64_t)pmap_find_phys(kernel_pmap, (addr64_t)((uintptr_t)pmap)) << 12) | (addr64_t)((unsigned int)pmap & 0xFFF); /* Get the physical address of the pmap */
                
                pmap->pmapvr = (addr64_t)((uintptr_t)pmap) ^ physpmap;  /* Make V to R translation mask */
                
                pmapTrans[pmap->space].pmapPAddr = physpmap;    /* Set translate table physical to point to us */
                pmapTrans[pmap->space].pmapVAddr = CAST_DOWN(unsigned int, pmap);       /* Set translate table virtual to point to us */
        }

        pmap->pmapVmmExt = 0;                                                   /* Clear VMM extension block vaddr */
        pmap->pmapVmmExtPhys = 0;                                               /*  and the paddr, too */
        pmap->pmapFlags = pmapKeyDef;                                   /* Set default key */
        pmap->pmapCCtl = pmapCCtlVal;                                   /* Initialize cache control */
        pmap->ref_count = 1;
        pmap->stats.resident_count = 0;
        pmap->stats.wired_count = 0;
        pmap->pmapSCSubTag = 0x0000000000000000ULL;             /* Make sure this is clean an tidy */
        simple_unlock(&free_pmap_lock);

        splx(s);
        return(pmap);
}

/* 
 * pmap_destroy
 * 
 * Gives up a reference to the specified pmap.  When the reference count 
 * reaches zero the pmap structure is added to the pmap free list.
 *
 * Should only be called if the map contains no valid mappings.
 */
void
pmap_destroy(pmap_t pmap)
{
        int ref_count;
        spl_t s;
        pmap_t fore, aft;

        if (pmap == PMAP_NULL)
                return;

        ref_count=hw_atomic_sub(&pmap->ref_count, 1);                   /* Back off the count */
        if(ref_count>0) return;                                                                 /* Still more users, leave now... */

        if(ref_count < 0)                                                                               /* Did we go too far? */
                panic("pmap_destroy(): ref_count < 0");

        if (!(pmap->pmapFlags & pmapVMgsaa)) {                                  /* Don't try this for a shadow assist guest */
                pmap_unmap_sharedpage(pmap);                                            /* Remove any mapping of page -1 */
        }
        
#ifdef notdef
        if(pmap->stats.resident_count != 0)
                panic("PMAP_DESTROY: pmap not empty");
#else
        if(pmap->stats.resident_count != 0) {
                pmap_remove(pmap, 0, 0xFFFFFFFFFFFFF000ULL);
        }
#endif

        /* 
         * Add the pmap to the pmap free list. 
         */

        s = splhigh();
        /* 
         * Add the pmap to the pmap free list. 
         */
        simple_lock(&free_pmap_lock);
        
        if (free_pmap_count <= free_pmap_max) {         /* Do we have enough spares? */
                
                pmap->freepmap = free_pmap_list;                /* Queue in front */
                free_pmap_list = pmap;
                free_pmap_count++;
                simple_unlock(&free_pmap_lock);

        } else {
                if(cursor_pmap == pmap) cursor_pmap = (pmap_t)pmap->pmap_link.prev;     /* If we are releasing the cursor, back up */
                fore = (pmap_t)pmap->pmap_link.prev;
                aft  = (pmap_t)pmap->pmap_link.next;
                fore->pmap_link.next = pmap->pmap_link.next;    /* My previous's next is my next */
                aft->pmap_link.prev = pmap->pmap_link.prev;             /* My next's previous is my previous */ 
                simple_unlock(&free_pmap_lock);
                pmapTrans[pmap->space].pmapPAddr = -1;                  /* Invalidate the translate table physical */
                pmapTrans[pmap->space].pmapVAddr = -1;                  /* Invalidate the translate table virtual */
                zfree(pmap_zone, pmap);
        }
        splx(s);
}

/*
 * pmap_reference(pmap)
 *      gains a reference to the specified pmap.
 */
void
pmap_reference(pmap_t pmap)
{
        if (pmap != PMAP_NULL) hw_atomic_add(&pmap->ref_count, 1);      /* Bump the count */
}

/*
 * pmap_remove_some_phys
 *
 *      Removes mappings of the associated page from the specified pmap
 *
 */
void pmap_remove_some_phys(
             pmap_t pmap,
             vm_offset_t pa)
{
        register struct phys_entry      *pp;
        register struct mapping         *mp;
        unsigned int pindex;

        if (pmap == PMAP_NULL) {                                        /* This should never be called with a null pmap */
                panic("pmap_remove_some_phys: null pmap\n");
        }

        pp = mapping_phys_lookup(pa, &pindex);          /* Get physical entry */
        if (pp == 0) return;                                            /* Leave if not in physical RAM */

        do {                                                                            /* Keep going until we toss all pages from this pmap */
                if (pmap->pmapFlags & pmapVMhost) {
                        mp = hw_purge_phys(pp);                         /* Toss a map */
                        switch ((unsigned int)mp & mapRetCode) {
                                case mapRtOK:
                                        mapping_free(mp);                       /* Return mapping to free inventory */
                                        break;
                                case mapRtGuest:
                                        break;                                          /* Don't try to return a guest mapping */
                                case mapRtEmpty:
                                        break;                                          /* Physent chain empty, we're done */
                                case mapRtNotFnd:                               
                                        break;                                          /* Mapping disappeared on us, retry */  
                                default:
                                        panic("pmap_remove_some_phys: hw_purge_phys failed - pp = %08X, pmap = %08X, code = %08X\n",
                                                        pp, pmap, mp);          /* Handle failure with our usual lack of tact */
                        }
                } else { 
                        mp = hw_purge_space(pp, pmap);          /* Toss a map */
                        switch ((unsigned int)mp & mapRetCode) {
                                case mapRtOK:
                                        mapping_free(mp);                       /* Return mapping to free inventory */
                                        break;
                                case mapRtEmpty:
                                        break;                                          /* Physent chain empty, we're done */
                                case mapRtNotFnd:                               
                                        break;                                          /* Mapping disappeared on us, retry */  
                                default:
                                        panic("pmap_remove_some_phys: hw_purge_phys failed - pp = %08X, pmap = %08X, code = %08X\n",
                                                        pp, pmap, mp);          /* Handle failure with our usual lack of tact */
                        }
                }
        } while (mapRtEmpty != ((unsigned int)mp & mapRetCode));

#if DEBUG       
        if ((pmap->pmapFlags & pmapVMhost) && !pmap_verify_free(pa)) 
                panic("pmap_remove_some_phys: cruft left behind - pa = %08X, pmap = %08X\n", pa, pmap);
#endif

        return;                                                                         /* Leave... */
}

/*
 * pmap_remove(pmap, s, e)
 *      unmaps all virtual addresses v in the virtual address
 *      range determined by [s, e) and pmap.
 *      s and e must be on machine independent page boundaries and
 *      s must be less than or equal to e.
 *
 *      Note that pmap_remove does not remove any mappings in nested pmaps. We just 
 *      skip those segments.
 */
void
pmap_remove(
            pmap_t pmap,
            addr64_t sva,
            addr64_t eva)
{
        addr64_t                va, endva;

        if (pmap == PMAP_NULL) return;                                  /* Leave if software pmap */


        /* It is just possible that eva might have wrapped around to zero,
         * and sometimes we get asked to liberate something of size zero
         * even though it's dumb (eg. after zero length read_overwrites)
         */
        assert(eva >= sva);

        /* If these are not page aligned the loop might not terminate */
        assert((sva == trunc_page_64(sva)) && (eva == trunc_page_64(eva)));

        va = sva & -4096LL;                                                     /* Round start down to a page */
        endva = eva & -4096LL;                                          /* Round end down to a page */

        while(1) {                                                                      /* Go until we finish the range */
                va = mapping_remove(pmap, va);                  /* Remove the mapping and see what's next */
                va = va & -4096LL;                                              /* Make sure the "not found" indication is clear */
                if((va == 0) || (va >= endva)) break;   /* End loop if we finish range or run off the end */
        }

}

/*
 *      Routine:
 *              pmap_page_protect
 *
 *      Function:
 *              Lower the permission for all mappings to a given page.
 */
void
pmap_page_protect(
        ppnum_t pa,
        vm_prot_t prot)
{
        register struct phys_entry      *pp;
        boolean_t                       remove;
        unsigned int            pindex;
        mapping_t                       *mp;


        switch (prot & VM_PROT_ALL) {
                case VM_PROT_READ:
                case VM_PROT_READ|VM_PROT_EXECUTE:
                        remove = FALSE;
                        break;
                case VM_PROT_ALL:
                        return;
                default:
                        remove = TRUE;
                        break;
        }


        pp = mapping_phys_lookup(pa, &pindex);          /* Get physical entry */
        if (pp == 0) return;                                            /* Leave if not in physical RAM */

        if (remove) {                                                           /* If the protection was set to none, we'll remove all mappings */
                
                do {                                                                    /* Keep going until we toss all pages from this physical page */
                        mp = hw_purge_phys(pp);                         /* Toss a map */
                        switch ((unsigned int)mp & mapRetCode) {
                                case mapRtOK:
                                                        mapping_free(mp);       /* Return mapping to free inventory */
                                                        break;
                                case mapRtGuest:
                                                        break;                          /* Don't try to return a guest mapping */
                                case mapRtNotFnd:
                                                        break;                          /* Mapping disappeared on us, retry */
                                case mapRtEmpty:
                                                        break;                          /* Physent chain empty, we're done */
                                default:        panic("pmap_page_protect: hw_purge_phys failed - pp = %08X, code = %08X\n",
                                                                  pp, mp);              /* Handle failure with our usual lack of tact */
                        }
                } while (mapRtEmpty != ((unsigned int)mp & mapRetCode));

#if DEBUG
                if (!pmap_verify_free(pa)) 
                        panic("pmap_page_protect: cruft left behind - pa = %08X\n", pa);
#endif

                return;                                                                 /* Leave... */
        }

/*      When we get here, it means that we are to change the protection for a 
 *      physical page.  
 */
 
        mapping_protect_phys(pa, (prot & VM_PROT_ALL) );                /* Change protection of all mappings to page. */

}

/*
 *      Routine:
 *              pmap_disconnect
 *
 *      Function:
 *              Disconnect all mappings for this page and return reference and change status
 *              in generic format.
 *
 */
unsigned int pmap_disconnect(
        ppnum_t pa)
{
        register struct phys_entry *pp;
        unsigned int                            pindex;
        mapping_t                                  *mp;
        
        pp = mapping_phys_lookup(pa, &pindex);          /* Get physical entry */
        if (pp == 0) return (0);                                        /* Return null ref and chg if not in physical RAM */
        do {                                                                            /* Iterate until all mappings are dead and gone */
                mp = hw_purge_phys(pp);                                 /* Disconnect a mapping */
                if (!mp) break;                                                 /* All mappings are gone, leave the loop */
                switch ((unsigned int)mp & mapRetCode) {
                        case mapRtOK:
                                                mapping_free(mp);               /* Return mapping to free inventory */
                                                break;
                        case mapRtGuest:
                                                break;                                  /* Don't try to return a guest mapping */
                        case mapRtNotFnd:
                                                break;                                  /* Mapping disappeared on us, retry */
                        case mapRtEmpty:
                                                break;                                  /* Physent chain empty, we're done */
                        default:        panic("hw_purge_phys: hw_purge_phys failed - pp = %08X, code = %08X\n",
                                                          pp, mp);                      /* Handle failure with our usual lack of tact */
                }
        } while (mapRtEmpty != ((unsigned int)mp & mapRetCode));

#if DEBUG
        if (!pmap_verify_free(pa)) 
                panic("pmap_disconnect: cruft left behind - pa = %08X\n", pa);
#endif

        return (mapping_tst_refmod(pa));                        /* Return page ref and chg in generic format */
}

/*
 * pmap_protect(pmap, s, e, prot)
 *      changes the protection on all virtual addresses v in the 
 *      virtual address range determined by [s, e] and pmap to prot.
 *      s and e must be on machine independent page boundaries and
 *      s must be less than or equal to e.
 *
 *      Note that any requests to change the protection of a nested pmap are
 *      ignored. Those changes MUST be done by calling this with the correct pmap.
 */
void pmap_protect(
             pmap_t pmap,
             vm_map_offset_t sva, 
             vm_map_offset_t eva,
             vm_prot_t prot)
{

        addr64_t va, endva;

        if (pmap == PMAP_NULL) return;                          /* Do nothing if no pmap */

        if (prot == VM_PROT_NONE) {                                     /* Should we kill the address range?? */
                pmap_remove(pmap, (addr64_t)sva, (addr64_t)eva);        /* Yeah, dump 'em */
                return;                                                                 /* Leave... */
        }

        va = sva & -4096LL;                                                     /* Round start down to a page */
        endva = eva & -4096LL;                                          /* Round end down to a page */

        while(1) {                                                                      /* Go until we finish the range */
                mapping_protect(pmap, va, (prot & VM_PROT_ALL), &va);   /* Change the protection and see what's next */
                if((va == 0) || (va >= endva)) break;   /* End loop if we finish range or run off the end */
        }

}



/*
 * pmap_enter
 *
 * Create a translation for the virtual address (virt) to the physical
 * address (phys) in the pmap with the protection requested. If the
 * translation is wired then we can not allow a full page fault, i.e., 
 * the mapping control block is not eligible to be stolen in a low memory
 * condition.
 *
 * NB: This is the only routine which MAY NOT lazy-evaluate
 *     or lose information.  That is, this routine must actually
 *     insert this page into the given map NOW.
 */
void
pmap_enter(pmap_t pmap, vm_map_offset_t va, ppnum_t pa, vm_prot_t prot, 
                unsigned int flags, __unused boolean_t wired)
{
        unsigned int            mflags;
        addr64_t                        colva;
        
        if (pmap == PMAP_NULL) return;                                  /* Leave if software pmap */

        mflags = 0;                                                                             /* Make sure this is initialized to nothing special */
        if(!(flags & VM_WIMG_USE_DEFAULT)) {                    /* Are they supplying the attributes? */
                mflags = mmFlgUseAttr | (flags & VM_MEM_GUARDED) | ((flags & VM_MEM_NOT_CACHEABLE) >> 1);       /* Convert to our mapping_make flags */
        }
        
/*
 *      It is possible to hang here if another processor is remapping any pages we collide with and are removing
 */ 

        while(1) {                                                                              /* Keep trying the enter until it goes in */
        
                colva = mapping_make(pmap, va, pa, mflags, 1, (prot & VM_PROT_ALL) );           /* Enter the mapping into the pmap */
                
                if(!colva) break;                                                       /* If there were no collisions, we are done... */
                
                mapping_remove(pmap, colva);                            /* Remove the mapping that collided */
        }
}

/*
 *              Enters translations for odd-sized V=F blocks.
 *
 *              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.
 *
 *              Any block that is larger than 256MB must be a multiple of 32MB.  We panic if it is not.
 *
 *              Note that pmap_map_block_rc is the same but doesn't panic if collision.
 *
 */
 
void pmap_map_block(pmap_t pmap, addr64_t va, ppnum_t pa, uint32_t size, vm_prot_t prot, int attr, unsigned int flags) {        /* Map an autogenned block */

        unsigned int            mflags;
        addr64_t                        colva;

        
        if (pmap == PMAP_NULL) {                                                /* Did they give us a pmap? */
                panic("pmap_map_block: null pmap\n");           /* No, like that's dumb... */
        }

//      kprintf("pmap_map_block: (%08X) va = %016llX, pa = %08X, size = %08X, prot = %08X, attr = %08X, flags = %08X\n",        /* (BRINGUP) */
//              current_thread(), va, pa, size, prot, attr, flags);     /* (BRINGUP) */

        mflags = mmFlgBlock | mmFlgUseAttr | (attr & VM_MEM_GUARDED) | ((attr & VM_MEM_NOT_CACHEABLE) >> 1);    /* Convert to our mapping_make flags */
        if(flags) mflags |= mmFlgPerm;                                  /* Mark permanent if requested */
        
        colva = mapping_make(pmap, va, pa, mflags, size, prot); /* Enter the mapping into the pmap */
        
        if(colva) {                                                                             /* If there was a collision, panic */
                panic("pmap_map_block: mapping error %d, pmap = %08X, va = %016llX\n", (uint32_t)(colva & mapRetCode), pmap, va);
        }
        
        return;                                                                                 /* Return */
}

int pmap_map_block_rc(pmap_t pmap, addr64_t va, ppnum_t pa, uint32_t size, vm_prot_t prot, int attr, unsigned int flags) {      /* Map an autogenned block */

        unsigned int            mflags;
        addr64_t                        colva;

        
        if (pmap == PMAP_NULL) {                                                /* Did they give us a pmap? */
                panic("pmap_map_block_rc: null pmap\n");        /* No, like that's dumb... */
        }

        mflags = mmFlgBlock | mmFlgUseAttr | (attr & VM_MEM_GUARDED) | ((attr & VM_MEM_NOT_CACHEABLE) >> 1);    /* Convert to our mapping_make flags */
        if(flags) mflags |= mmFlgPerm;                                  /* Mark permanent if requested */

        colva = mapping_make(pmap, va, pa, mflags, size, prot); /* Enter the mapping into the pmap */
        
        if(colva) return 0;                                                             /* If there was a collision, fail */
        
        return 1;                                                                               /* Return true of we worked */
}

/*
 * pmap_extract(pmap, va)
 *      returns the physical address corrsponding to the 
 *      virtual address specified by pmap and va if the
 *      virtual address is mapped and 0 if it is not.
 *      Note: we assume nothing is ever mapped to phys 0.
 *
 *      NOTE: This call always will fail for physical addresses greater than 0xFFFFF000.
 */
vm_offset_t pmap_extract(pmap_t pmap, vm_map_offset_t va) {

        spl_t                                   spl;
        register struct mapping *mp;
        register vm_offset_t    pa;
        addr64_t                                nextva;
        ppnum_t                                 ppoffset;
        unsigned int                    gva;

#ifdef BOGUSCOMPAT
        panic("pmap_extract: THIS CALL IS BOGUS. NEVER USE IT EVER. So there...\n");    /* Don't use this */
#else

        gva = (unsigned int)va;                                                 /* Make sure we don't have a sign */

        spl = splhigh();                                                                /* We can't allow any loss of control here */
        
        mp = mapping_find(pmap, (addr64_t)gva, &nextva,1);      /* Find the mapping for this address */
        
        if(!mp) {                                                                               /* Is the page mapped? */
                splx(spl);                                                                      /* Enable interrupts */
                return 0;                                                                       /* Pass back 0 if not found */
        }

        ppoffset = (ppnum_t)(((gva & -4096LL) - (mp->mpVAddr & -4096LL)) >> 12);        /* Get offset from va to base va */
        
        
        pa = mp->mpPAddr + ppoffset;                                    /* Remember ppage because mapping may vanish after drop call */
                        
        mapping_drop_busy(mp);                                                  /* We have everything we need from the mapping */
        splx(spl);                                                                              /* Restore 'rupts */

        if(pa > maxPPage32) return 0;                                   /* Force large addresses to fail */
        
        pa = (pa << 12) | (va & 0xFFF);                                 /* Convert physical page number to address */
        
#endif
        return pa;                                                                              /* Return physical address or 0 */
}

/*
 * ppnum_t pmap_find_phys(pmap, addr64_t va)
 *      returns the physical page corrsponding to the 
 *      virtual address specified by pmap and va if the
 *      virtual address is mapped and 0 if it is not.
 *      Note: we assume nothing is ever mapped to phys 0.
 *
 */
ppnum_t pmap_find_phys(pmap_t pmap, addr64_t va) {

        spl_t                                   spl;
        register struct mapping *mp;
        ppnum_t                                 pa, ppoffset;
        addr64_t                                nextva;

        spl = splhigh();                                                                /* We can't allow any loss of control here */
        
        mp = mapping_find(pmap, va, &nextva, 1);                /* Find the mapping for this address */
        
        if(!mp) {                                                                               /* Is the page mapped? */
                splx(spl);                                                                      /* Enable interrupts */
                return 0;                                                                       /* Pass back 0 if not found */
        }
                
        
        ppoffset = (ppnum_t)(((va & -4096LL) - (mp->mpVAddr & -4096LL)) >> 12); /* Get offset from va to base va */
        
        pa = mp->mpPAddr + ppoffset;                                    /* Get the actual physical address */

        mapping_drop_busy(mp);                                                  /* We have everything we need from the mapping */

        splx(spl);                                                                              /* Restore 'rupts */
        return pa;                                                                              /* Return physical address or 0 */
}


/*
 *      pmap_attributes:
 *
 *      Set/Get special memory attributes; not implemented.
 *
 *      Note: 'VAL_GET_INFO' is used to return info about a page.
 *        If less than 1 page is specified, return the physical page
 *        mapping and a count of the number of mappings to that page.
 *        If more than one page is specified, return the number
 *        of resident pages and the number of shared (more than
 *        one mapping) pages in the range;
 *
 *
 */
kern_return_t
pmap_attribute(
        __unused pmap_t                         pmap,
        __unused vm_map_offset_t                address,
        __unused vm_map_size_t                  size,
        __unused vm_machine_attribute_t         attribute,
        __unused vm_machine_attribute_val_t*    value)  
{
        
        return KERN_INVALID_ARGUMENT;

}



unsigned int pmap_cache_attributes(ppnum_t pgn) {

        unsigned int    flags;
        struct phys_entry * pp;

        // Find physical address
        if ((pp = pmap_find_physentry(pgn))) {
                // Use physical attributes as default
                // NOTE: DEVICE_PAGER_FLAGS are made to line up
                flags = VM_MEM_COHERENT;                                /* We only support coherent memory */
                if (pp->ppLink & ppG) flags |= VM_MEM_GUARDED;          /* Add in guarded if it is */
                if (pp->ppLink & ppI) flags |= VM_MEM_NOT_CACHEABLE;    /* Add in cache inhibited if so */
        } else
                // If no physical, just hard code attributes
                flags = VM_WIMG_IO;

        return (flags);
}



/*
 * pmap_attribute_cache_sync(vm_offset_t pa)
 * 
 * Invalidates all of the instruction cache on a physical page and
 * pushes any dirty data from the data cache for the same physical page
 */
 
kern_return_t pmap_attribute_cache_sync(ppnum_t pp, vm_size_t size,
                                __unused vm_machine_attribute_t  attribute,
                                __unused vm_machine_attribute_val_t* value) {
        
        spl_t s;
        unsigned int i, npages;
        
        npages = round_page(size) >> 12;                        /* Get the number of pages to do */
        
        for(i = 0; i < npages; i++) {                           /* Do all requested pages */
                s = splhigh();                                                  /* No interruptions here */
                sync_ppage(pp + i);                                             /* Go flush data cache and invalidate icache */
                splx(s);                                                                /* Allow interruptions */
        }
        
        return KERN_SUCCESS;
}

/*
 * pmap_sync_page_data_phys(ppnum_t pa)
 * 
 * Invalidates all of the instruction cache on a physical page and
 * pushes any dirty data from the data cache for the same physical page
 */
 
void pmap_sync_page_data_phys(ppnum_t pa) {
        
        spl_t s;
        
        s = splhigh();                                                          /* No interruptions here */
        sync_ppage(pa);                                                         /* Sync up dem caches */
        splx(s);                                                                        /* Allow interruptions */
        return;
}

void
pmap_sync_page_attributes_phys(ppnum_t pa)
{
        pmap_sync_page_data_phys(pa);
}

/*
 * pmap_collect
 * 
 * Garbage collects the physical map system for pages that are no longer used.
 * It isn't implemented or needed or wanted.
 */
void
pmap_collect(__unused pmap_t pmap)
{
        return;
}

/*
 *      Routine:        pmap_activate
 *      Function:
 *              Binds the given physical map to the given
 *              processor, and returns a hardware map description.
 *              It isn't implemented or needed or wanted.
 */
void
pmap_activate(
        __unused pmap_t pmap,
        __unused thread_t th,
        __unused int which_cpu)
{
        return;
}
/*
 * pmap_deactivate:
 * It isn't implemented or needed or wanted.
 */
void
pmap_deactivate(
        __unused pmap_t pmap,
        __unused thread_t th,
        __unused int which_cpu)
{
        return;
}


/*
 * pmap_pageable(pmap, s, e, pageable)
 *      Make the specified pages (by pmap, offset)
 *      pageable (or not) as requested.
 *
 *      A page which is not pageable may not take
 *      a fault; therefore, its page table entry
 *      must remain valid for the duration.
 *
 *      This routine is merely advisory; pmap_enter()
 *      will specify that these pages are to be wired
 *      down (or not) as appropriate.
 *
 *      (called from vm/vm_fault.c).
 */
void
pmap_pageable(
        __unused pmap_t                         pmap,
        __unused vm_map_offset_t        start,
        __unused vm_map_offset_t        end,
        __unused boolean_t                      pageable)
{

        return;                                                                                         /* This is not used... */

}
/*
 *      Routine:        pmap_change_wiring
 *      NOT USED ANYMORE.
 */
void
pmap_change_wiring(
        __unused pmap_t                         pmap,
        __unused vm_map_offset_t        va,
        __unused boolean_t                      wired)
{
        return;                                                                                         /* This is not used... */
}

/*
 * pmap_modify_pages(pmap, s, e)
 *      sets the modified bit on all virtual addresses v in the 
 *      virtual address range determined by [s, e] and pmap,
 *      s and e must be on machine independent page boundaries and
 *      s must be less than or equal to e.
 *
 *  Note that this function will not descend nested pmaps.
 */
void
pmap_modify_pages(
             pmap_t pmap,
             vm_map_offset_t sva, 
             vm_map_offset_t eva)
{
        spl_t           spl;
        mapping_t       *mp;
        ppnum_t         pa;
        addr64_t                va, endva;
        unsigned int    savetype;

        if (pmap == PMAP_NULL) return;                                  /* If no pmap, can't do it... */
        
        va = sva & -4096;                                                               /* Round to page */
        endva = eva & -4096;                                                    /* Round to page */

        while (va < endva) {                                                    /* Walk through all pages */

                spl = splhigh();                                                        /* We can't allow any loss of control here */
        
                mp = mapping_find(pmap, (addr64_t)va, &va, 0);  /* Find the mapping for this address */
                
                if(!mp) {                                                                       /* Is the page mapped? */
                        splx(spl);                                                              /* Page not mapped, restore interruptions */
                        if((va == 0) || (va >= endva)) break;   /* We are done if there are no more or we hit the end... */
                        continue;                                                               /* We are not done and there is more to check... */
                }
                
                savetype = mp->mpFlags & mpType;                        /* Remember the type */
                pa = mp->mpPAddr;                                                       /* Remember ppage because mapping may vanish after drop call */
        
                mapping_drop_busy(mp);                                          /* We have everything we need from the mapping */
        
                splx(spl);                                                                      /* Restore 'rupts */
        
                if(savetype != mpNormal) continue;                      /* Can't mess around with these guys... */      
                
                mapping_set_mod(pa);                                            /* Set the modfied bit for this page */
                
                if(va == 0) break;                                                      /* We hit the end of the pmap, might as well leave now... */
        }
        return;                                                                                 /* Leave... */
}

/*
 * pmap_clear_modify(phys)
 *      clears the hardware modified ("dirty") bit for one
 *      machine independant page starting at the given
 *      physical address.  phys must be aligned on a machine
 *      independant page boundary.
 */
void
pmap_clear_modify(ppnum_t pa)
{

        mapping_clr_mod(pa);                            /* Clear all change bits for physical page */

}

/*
 * pmap_is_modified(phys)
 *      returns TRUE if the given physical page has been modified 
 *      since the last call to pmap_clear_modify().
 */
boolean_t
pmap_is_modified(register ppnum_t pa)
{
        return mapping_tst_mod(pa);     /* Check for modified */
        
}

/*
 * pmap_clear_reference(phys)
 *      clears the hardware referenced bit in the given machine
 *      independant physical page.  
 *
 */
void
pmap_clear_reference(ppnum_t pa)
{
        mapping_clr_ref(pa);                    /* Check for modified */
}

/*
 * pmap_is_referenced(phys)
 *      returns TRUE if the given physical page has been referenced 
 *      since the last call to pmap_clear_reference().
 */
boolean_t
pmap_is_referenced(ppnum_t pa)
{
        return mapping_tst_ref(pa);     /* Check for referenced */
}

/*
 * pmap_get_refmod(phys)
 *  returns the referenced and modified bits of the specified
 *  physical page.
 */
unsigned int
pmap_get_refmod(ppnum_t pa)
{
        return (mapping_tst_refmod(pa));
}

/*
 * pmap_clear_refmod(phys, mask)
 *  clears the referenced and modified bits as specified by the mask
 *  of the specified physical page.
 */
void
pmap_clear_refmod(ppnum_t pa, unsigned int mask)
{
        mapping_clr_refmod(pa, mask);
}

/*
 * pmap_eligible_for_execute(ppnum_t pa)
 *      return true if physical address is eligible to contain executable code;
 *  otherwise, return false
 */
boolean_t
pmap_eligible_for_execute(ppnum_t pa)
{
        phys_entry_t *physent;
        unsigned int  pindex;

        physent = mapping_phys_lookup(pa, &pindex);                             /* Get physical entry */

        if((!physent) || (physent->ppLink & ppG))
                return 0;                                                                                       /* If there is no physical entry or marked guarded,
                                                                       the entry is not eligible for execute */

        return 1;                                                                                               /* Otherwise, entry is eligible for execute */
}

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

/*
 * Locking:
 *      spl: VM
 */
void
pmap_copy_part_page(
        vm_offset_t     src,
        vm_offset_t     src_offset,
        vm_offset_t     dst,
        vm_offset_t     dst_offset,
        vm_size_t       len)
{
        addr64_t fsrc, fdst;

        assert(((dst <<12) & PAGE_MASK+dst_offset+len) <= PAGE_SIZE);
        assert(((src <<12) & PAGE_MASK+src_offset+len) <= PAGE_SIZE);

        fsrc = ((addr64_t)src << 12) + src_offset;
        fdst = ((addr64_t)dst << 12) + dst_offset;

        phys_copy(fsrc, fdst, len);                                                             /* Copy the stuff physically */
}

void
pmap_zero_part_page(
        __unused vm_offset_t            p,
        __unused vm_offset_t    offset,
        __unused vm_size_t      len)
{
    panic("pmap_zero_part_page");
}

boolean_t pmap_verify_free(ppnum_t pa) {

        struct phys_entry       *pp;
        unsigned int pindex;

        pp = mapping_phys_lookup(pa, &pindex);  /* Get physical entry */
        if (pp == 0) return FALSE;                                      /* If there isn't one, show no mapping... */

        if(pp->ppLink & ~(ppLock | ppFlags)) return FALSE;      /* We have at least one mapping */
        return TRUE;                                                            /* No mappings */
}


/* Determine if we need to switch space and set up for it if so */

void pmap_switch(pmap_t map)
{
        hw_blow_seg(lowGlo.lgUMWvaddr);                                 /* Blow off the first segment */
        hw_blow_seg(lowGlo.lgUMWvaddr + 0x10000000ULL); /* Blow off the second segment */

/* when changing to kernel space, don't bother
 * doing anything, the kernel is mapped from here already.
 */
        if (map->space == PPC_SID_KERNEL) {                     /* Are we switching into kernel space? */
                return;                                                                 /* If so, we don't do anything... */
        }
        
        hw_set_user_space(map);                                         /* Indicate if we need to load the SRs or not */
        return;                                                                         /* Bye, bye, butterfly... */
}

/*
 *      kern_return_t pmap_nest(grand, subord, vstart, size)
 *
 *      grand  = the pmap that we will nest subord into
 *      subord = the pmap that goes into the grand
 *      vstart  = start of range in pmap to be inserted
 *      nstart  = start of range in pmap nested pmap
 *      size   = Size of nest area (up to 2TB)
 *
 *      Inserts a pmap into another.  This is used to implement shared segments.
 *      On the current PPC processors, this is limited to segment (256MB) aligned
 *      segment sized ranges.
 *
 *      We actually kinda allow recursive nests.  The gating factor is that we do not allow 
 *      nesting on top of something that is already mapped, i.e., the range must be empty.
 *
 *      Note that we depend upon higher level VM locks to insure that things don't change while
 *      we are doing this.  For example, VM should not be doing any pmap enters while it is nesting
 *      or do 2 nests at once.
 */

kern_return_t pmap_nest(pmap_t grand, pmap_t subord, addr64_t vstart, addr64_t nstart, uint64_t size) {
                
        addr64_t vend, colladdr;
        unsigned int msize;
        int nlists;
        mapping_t *mp;
        
        if(size & 0x0FFFFFFFULL) return KERN_INVALID_VALUE;     /* We can only do this for multiples of 256MB */
        if((size >> 25) > 65536)  return KERN_INVALID_VALUE;    /* Max size we can nest is 2TB */
        if(vstart & 0x0FFFFFFFULL) return KERN_INVALID_VALUE;   /* We can only do this aligned to 256MB */
        if(nstart & 0x0FFFFFFFULL) return KERN_INVALID_VALUE;   /* We can only do this aligned to 256MB */
        
        if(size == 0) {                                                         /*      Is the size valid? */
                panic("pmap_nest: size is invalid - %016llX\n", size);
        }
        
        msize = (size >> 25) - 1;                                                       /* Change size to blocks of 32MB */
        
        nlists = mapSetLists(grand);                                            /* Set number of lists this will be on */

        mp = mapping_alloc(nlists);                                                     /* Get a spare mapping block */
        
        mp->mpFlags = 0x01000000 | mpNest | mpPerm | mpBSu | nlists;    /* Make this a permanent nested pmap with a 32MB basic size unit */
                                                                                                                /* Set the flags. Make sure busy count is 1 */
        mp->mpSpace = subord->space;                                            /* Set the address space/pmap lookup ID */
        mp->u.mpBSize = msize;                                                          /* Set the size */
        mp->mpPte = 0;                                                                          /* Set the PTE invalid */
        mp->mpPAddr = 0;                                                                        /* Set the physical page number */
        mp->mpVAddr = vstart;                                                           /* Set the address */
        mp->mpNestReloc = nstart - vstart;                                      /* Set grand to nested vaddr relocation value */
        
        colladdr = hw_add_map(grand, mp);                                       /* Go add the mapping to the pmap */
        
        if(colladdr) {                                                                          /* Did it collide? */
                vend = vstart + size - 4096;                                    /* Point to the last page we would cover in nest */     
                panic("pmap_nest: attempt to nest into a non-empty range - pmap = %08X, start = %016llX, end = %016llX\n",
                        grand, vstart, vend);
        }
        
        return KERN_SUCCESS;
}

/*
 *      kern_return_t pmap_unnest(grand, vaddr)
 *
 *      grand  = the pmap that we will nest subord into
 *      vaddr  = start of range in pmap to be unnested
 *
 *      Removes a pmap from another.  This is used to implement shared segments.
 *      On the current PPC processors, this is limited to segment (256MB) aligned
 *      segment sized ranges.
 */

kern_return_t pmap_unnest(pmap_t grand, addr64_t vaddr) {
                        
        unsigned int tstamp, i, mycpu;
        addr64_t nextva;
        spl_t s;
        mapping_t *mp;
                
        s = splhigh();                                                                          /* Make sure interruptions are disabled */

        mp = mapping_find(grand, vaddr, &nextva, 0);            /* Find the nested map */

        if(((unsigned int)mp & mapRetCode) != mapRtOK) {        /* See if it was even nested */
                panic("pmap_unnest: Attempt to unnest an unnested segment - va = %016llX\n", vaddr);
        }

        if((mp->mpFlags & mpType) != mpNest) {                          /* Did we find something other than a nest? */
                panic("pmap_unnest: Attempt to unnest something that is not a nest - va = %016llX\n", vaddr);
        }
        
        if(mp->mpVAddr != vaddr) {                                                      /* Make sure the address is the same */
                panic("pmap_unnest: Attempt to unnest something that is not at start of nest - va = %016llX\n", vaddr);
        }

        (void)hw_atomic_and(&mp->mpFlags, ~mpPerm);                     /* Show that this mapping is now removable */
        
        mapping_drop_busy(mp);                                                          /* Go ahead and release the mapping now */

        splx(s);                                                                                        /* Restore 'rupts */
                
        (void)mapping_remove(grand, vaddr);                                     /* Toss the nested pmap mapping */
        
        invalidateSegs(grand);                                                          /* Invalidate the pmap segment cache */
        
/*
 *      Note that the following will force the segment registers to be reloaded 
 *      on all processors (if they are using the pmap we just changed) before returning.
 *
 *      This is needed.  The reason is that until the segment register is 
 *      reloaded, another thread in the same task on a different processor will
 *      be able to access memory that it isn't allowed to anymore.  That can happen
 *      because access to the subordinate pmap is being removed, but the pmap is still
 *      valid.
 *
 *      Note that we only kick the other processor if we see that it was using the pmap while we
 *      were changing it.
 */


        for(i=0; i < real_ncpus; i++) {                                         /* Cycle through processors */
                disable_preemption();
                mycpu = cpu_number();                                                           /* Who am I? Am I just a dream? */
                if((unsigned int)grand == PerProcTable[i].ppe_vaddr->ppUserPmapVirt) {  /* Is this guy using the changed pmap? */
                        
                        PerProcTable[i].ppe_vaddr->ppInvSeg = 1;        /* Show that we need to invalidate the segments */
                        
                        if(i != mycpu) {
                
                                tstamp = PerProcTable[i].ppe_vaddr->ruptStamp[1];               /* Save the processor's last interrupt time stamp */
                                if(cpu_signal(i, SIGPcpureq, CPRQsegload, 0) == KERN_SUCCESS) { /* Make sure we see the pmap change */
                                        if(!hw_cpu_wcng(&PerProcTable[i].ppe_vaddr->ruptStamp[1], tstamp, LockTimeOut)) {       /* Wait for the other processors to enter debug */
                                                panic("pmap_unnest: Other processor (%d) did not see interruption request\n", i);
                                        }
                                }
                        }
                }
                enable_preemption();
        }

        return KERN_SUCCESS;                                                            /* Bye, bye, butterfly... */
}


/*
 *      void MapUserMemoryWindowInit(void)
 *
 *      Initialize anything we need to in order to map user address space slices into
 *      the kernel.  Primarily used for copy in/out.
 *
 *      Currently we only support one 512MB slot for this purpose.  There are two special
 *      mappings defined for the purpose: the special pmap nest, and linkage mapping.
 *
 *      The special pmap nest (which is allocated in this function) is used as a place holder
 *      in the kernel's pmap search list. It is 512MB long and covers the address range
 *      starting at lgUMWvaddr.  It points to no actual memory and when the fault handler 
 *      hits in it, it knows to look in the per_proc and start using the linkage
 *      mapping contained therin.
 *
 *      The linkage mapping is used to glue the user address space slice into the 
 *      kernel.  It contains the relocation information used to transform the faulting
 *      kernel address into the user address space.  It also provides the link to the
 *      user's pmap.  This is pointed to by the per_proc and is switched in and out
 *      whenever there is a context switch.
 *
 */

void MapUserMemoryWindowInit(void) {
                
        addr64_t colladdr;
        int nlists;
        mapping_t *mp;
        
        nlists = mapSetLists(kernel_pmap);                                      /* Set number of lists this will be on */
        
        mp = mapping_alloc(nlists);                                                     /* Get a spare mapping block */

        mp->mpFlags = 0x01000000 | mpLinkage | mpPerm | mpBSu | nlists; /* Make this a permanent nested pmap with a 32MB basic size unit */
                                                                                                                /* Set the flags. Make sure busy count is 1 */
        mp->mpSpace = kernel_pmap->space;                                       /* Set the address space/pmap lookup ID */
        mp->u.mpBSize = 15;                                                                     /* Set the size to 2 segments in 32MB chunks - 1 */
        mp->mpPte = 0;                                                                          /* Means nothing */
        mp->mpPAddr = 0;                                                                        /* Means nothing */
        mp->mpVAddr = lowGlo.lgUMWvaddr;                                        /* Set the address range we cover */
        mp->mpNestReloc = 0;                                                            /* Means nothing */
        
        colladdr = hw_add_map(kernel_pmap, mp);                         /* Go add the mapping to the pmap */
        
        if(colladdr) {                                                                          /* Did it collide? */
                panic("MapUserMemoryWindowInit: MapUserMemoryWindow range already mapped\n");
        }
        
        return;
}

/*
 *      addr64_t MapUserMemoryWindow(vm_map_t map, vm_offset_t va, size)
 *
 *      map  = the vm_map that we are mapping into the kernel
 *      va = start of the address range we are mapping
 *      Note that we do not test validty, we chose to trust our fellows...
 *
 *      Maps a 512M slice of a user address space into a predefined kernel range
 *      on a per-thread basis. We map only the first 256M segment, allowing the
 *  second 256M segment to fault in as needed. This allows our clients to access
 *  an arbitrarily aligned operand up to 256M in size.
 *
 *  In the future, the restriction of a predefined range may be loosened.
 *
 *      Builds the proper linkage map to map the user range
 *  We will round this down to the previous segment boundary and calculate
 *      the relocation to the kernel slot
 *
 *      We always make a segment table entry here if we need to.  This is mainly because of
 *      copyin/out and if we don't, there will be multiple segment faults for
 *      each system call.  I have seen upwards of 30000 per second.
 *
 *      We do check, however, to see if the slice is already mapped and if so,
 *      we just exit.  This is done for performance reasons.  It was found that 
 *      there was a considerable boost in copyin/out performance if we did not
 *      invalidate the segment at ReleaseUserAddressSpace time, so we dumped the
 *      restriction that you had to bracket MapUserMemoryWindow.  Further, there 
 *      is a yet further boost if you didn't need to map it each time.  The theory
 *      behind this is that many times copies are to or from the same segment and
 *      done multiple times within the same system call.  To take advantage of that,
 *      we check umwSpace and umwRelo to see if we've already got it.  
 *
 *      We also need to half-invalidate the slice when we context switch or go
 *      back to user state.  A half-invalidate does not clear the actual mapping,
 *      but it does force the MapUserMemoryWindow function to reload the segment
 *      register/SLBE.  If this is not done, we can end up some pretty severe
 *      performance penalties. If we map a slice, and the cached space/relocation is
 *      the same, we won't reload the segment registers.  Howver, since we ran someone else,
 *      our SR is cleared and we will take a fault.  This is reasonable if we block
 *      while copying (e.g., we took a page fault), but it is not reasonable when we 
 *      just start.  For this reason, we half-invalidate to make sure that the SR is
 *      explicitly reloaded.
 *       
 *      Note that we do not go to the trouble of making a pmap segment cache
 *      entry for these guys because they are very short term -- 99.99% of the time
 *      they will be unmapped before the next context switch.
 *
 */

addr64_t MapUserMemoryWindow(
        vm_map_t map,
        addr64_t va) {
                
        addr64_t baddrs, reladd;
        thread_t thread;
        mapping_t *mp;
        
        baddrs = va & 0xFFFFFFFFF0000000ULL;                            /* Isolate the segment */
        thread = current_thread();                                                      /* Remember our activation */

        reladd = baddrs - lowGlo.lgUMWvaddr;                            /* Get the relocation from user to kernel */
        
        if((thread->machine.umwSpace == map->pmap->space) && (thread->machine.umwRelo == reladd)) {     /* Already mapped? */
                return ((va & 0x0FFFFFFFULL) | lowGlo.lgUMWvaddr);      /* Pass back the kernel address we are to use */
        }

        disable_preemption();                                                           /* Don't move... */     
        
        mp = (mapping_t *)&(getPerProc()->ppUMWmp);                     /* Make up for C */
        thread->machine.umwRelo = reladd;                                       /* Relocation from user to kernel */
        mp->mpNestReloc = reladd;                                                       /* Relocation from user to kernel */
        
        thread->machine.umwSpace = map->pmap->space;            /* Set the address space/pmap lookup ID */
        mp->mpSpace = map->pmap->space;                                         /* Set the address space/pmap lookup ID */
        
/*
 *      Here we make an assumption that we are going to be using the base pmap's address space.
 *      If we are wrong, and that would be very, very, very rare, the fault handler will fix us up.
 */ 

        hw_map_seg(map->pmap,  lowGlo.lgUMWvaddr, baddrs);      /* Make the entry for the first segment */

        enable_preemption();                                                            /* Let's move */
        return ((va & 0x0FFFFFFFULL) | lowGlo.lgUMWvaddr);      /* Pass back the kernel address we are to use */
}


/*
 *      kern_return_t pmap_boot_map(size)
 *
 *      size   = size of virtual address range to be mapped
 *
 *      This function is used to assign a range of virtual addresses before VM in 
 *      initialized.  It starts at VM_MAX_KERNEL_ADDRESS and works downward.
 *      The variable vm_last_addr contains the current highest possible VM
 *      assignable address.  It is a panic to attempt to call this after VM has
 *      started up.  The only problem is, is that we may not have the serial or
 *      framebuffer mapped, so we'll never know we died.........
 */

vm_offset_t pmap_boot_map(vm_size_t size) {
                        
        if(kernel_map != VM_MAP_NULL) {                         /* Has VM already started? */
                panic("pmap_boot_map: VM started\n");
        }
        
        size = round_page(size);                                        /* Make sure this is in pages */
        vm_last_addr = vm_last_addr - size;                     /* Allocate the memory */
        return (vm_last_addr + 1);                                      /* Return the vaddr we just allocated */

}


/*
 *      void pmap_init_sharedpage(void);
 *
 *      Hack map for the 64-bit commpage
 */

void pmap_init_sharedpage(vm_offset_t cpg){
        
        addr64_t cva, cpoff;
        ppnum_t cpphys;
        
        sharedPmap = pmap_create(0, FALSE);                             /* Get a pmap to hold the common segment */
        if(!sharedPmap) {                                                       /* Check for errors */
                panic("pmap_init_sharedpage: couldn't make sharedPmap\n");
        }

        for(cpoff = 0; cpoff < _COMM_PAGE_AREA_USED; cpoff += 4096) {   /* Step along now */
        
                cpphys = pmap_find_phys(kernel_pmap, (addr64_t)cpg + cpoff);
                if(!cpphys) {
                        panic("pmap_init_sharedpage: compage %08X not mapped in kernel\n", cpg + cpoff);
                }
                
                cva = mapping_make(sharedPmap, (addr64_t)((uint32_t)_COMM_PAGE_BASE_ADDRESS) + cpoff,
                        cpphys, mmFlgPerm, 1, VM_PROT_READ | VM_PROT_EXECUTE);          /* Map the page read/execute only */
                if(cva) {                                                               /* Check for errors */
                        panic("pmap_init_sharedpage: couldn't map commpage page - cva = %016llX\n", cva);
                }
        
        }
                
        return;
}


/*
 *      void pmap_map_sharedpage(pmap_t pmap);
 *
 *      Maps the last segment in a 64-bit address space
 *
 *      
 */

void pmap_map_sharedpage(task_t task, pmap_t pmap){
        
        kern_return_t ret;

        if(task_has_64BitAddr(task) || _cpu_capabilities & k64Bit) {    /* Should we map the 64-bit page -1? */
                ret = pmap_nest(pmap, sharedPmap, 0xFFFFFFFFF0000000ULL, 0x00000000F0000000ULL,
                        0x0000000010000000ULL);                         /* Nest the highest possible segment to map comm page */
                if(ret != KERN_SUCCESS) {                               /* Did it work? */
                        panic("pmap_map_sharedpage: couldn't nest shared page - ret = %08X\n", ret);
                }
        }

        return;
}


/*
 *      void pmap_unmap_sharedpage(pmap_t pmap);
 *
 *      Unmaps the last segment in a 64-bit address space
 *
 */

void pmap_unmap_sharedpage(pmap_t pmap){
        
        kern_return_t ret;
        mapping_t *mp;
        boolean_t inter;
        int gotnest;
        addr64_t nextva;

        if(BootProcInfo.pf.Available & pf64Bit) {               /* Are we on a 64-bit machine? */
                
                inter  = ml_set_interrupts_enabled(FALSE);      /* Disable interruptions for now */
                mp = hw_find_map(pmap, 0xFFFFFFFFF0000000ULL, &nextva); /* Find the mapping for this address */
                if((unsigned int)mp == mapRtBadLk) {            /* Did we lock up ok? */
                        panic("pmap_unmap_sharedpage: mapping lock failure - rc = %08X, pmap = %08X\n", mp, pmap);      /* Die... */
                }
                
                gotnest = 0;                                                            /* Assume nothing here */
                if(mp) {
                        gotnest = ((mp->mpFlags & mpType) == mpNest);
                                                                                                        /* Remember if we have a nest here */
                        mapping_drop_busy(mp);                                  /* We have everything we need from the mapping */
                }
                ml_set_interrupts_enabled(inter);                       /* Put interrupts back to what they were */
                
                if(!gotnest) return;                                            /* Leave if there isn't any nesting here */
                
                ret = pmap_unnest(pmap, 0xFFFFFFFFF0000000ULL); /* Unnest the max 64-bit page */
                
                if(ret != KERN_SUCCESS) {                                       /* Did it work? */
                        panic("pmap_unmap_sharedpage: couldn't unnest shared page - ret = %08X\n", ret);
                }
        }
        
        return;
}


/* temporary workaround */
boolean_t
coredumpok(
        __unused vm_map_t map,
        __unused vm_offset_t va)
{
        return TRUE;
}


/*
 * disable no-execute capability on
 * the specified pmap
 */
void pmap_disable_NX(pmap_t pmap) {
  
        pmap->pmapFlags |= pmapNXdisabled;
}