src/mem/physical.cc - arm/gem5 - Git at Google

 /*
  * Copyright (c) 2012 ARM Limited
  * All rights reserved
  *
  * The license below extends only to copyright in the software and shall
  * not be construed as granting a license to any other intellectual
  * property including but not limited to intellectual property relating
  * to a hardware implementation of the functionality of the software
  * licensed hereunder.  You may use the software subject to the license
  * terms below provided that you ensure that this notice is replicated
  * unmodified and in its entirety in all distributions of the software,
  * modified or unmodified, in source code or in binary form.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met: redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer;
  * redistributions in binary form must reproduce the above copyright
  * notice, this list of conditions and the following disclaimer in the
  * documentation and/or other materials provided with the distribution;
  * neither the name of the copyright holders nor the names of its
  * contributors may be used to endorse or promote products derived from
  * this software without specific prior written permission.
  *
  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
  * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  *
  * Authors: Andreas Hansson
  */

 #include <sys/mman.h>
 #include <sys/types.h>
 #include <sys/user.h>
 #include <fcntl.h>
 #include <unistd.h>
 #include <zlib.h>

 #include <cerrno>
 #include <climits>
 #include <cstdio>
 #include <iostream>
 #include <string>

 #include "base/trace.hh"
 #include "debug/BusAddrRanges.hh"
 #include "debug/Checkpoint.hh"
 #include "mem/abstract_mem.hh"
 #include "mem/physical.hh"

 using namespace std;

 PhysicalMemory::PhysicalMemory(const string& _name,
                                const vector<AbstractMemory*>& _memories) :
     _name(_name), size(0)
 {
     // add the memories from the system to the address map as
     // appropriate
     for (vector<AbstractMemory*>::const_iterator m = _memories.begin();
          m != _memories.end(); ++m) {
         // only add the memory if it is part of the global address map
         if ((*m)->isInAddrMap()) {
             memories.push_back(*m);

             // calculate the total size once and for all
             size += (*m)->size();

             // add the range to our interval tree and make sure it does not
             // intersect an existing range
             if (addrMap.insert((*m)->getAddrRange(), *m) == addrMap.end())
                 fatal("Memory address range for %s is overlapping\n",
                       (*m)->name());
         } else {
             DPRINTF(BusAddrRanges,
                     "Skipping memory %s that is not in global address map\n",
                     (*m)->name());
             // this type of memory is used e.g. as reference memory by
             // Ruby, and they also needs a backing store, but should
             // not be part of the global address map

             // simply do it independently, also note that this kind of
             // memories are allowed to overlap in the logic address
             // map
             vector<AbstractMemory*> unmapped_mems;
             unmapped_mems.push_back(*m);
             createBackingStore((*m)->getAddrRange(), unmapped_mems);
         }
     }

     // iterate over the increasing addresses and chunks of contigous
     // space to be mapped to backing store, also remember what
     // memories constitute the range so we can go and find out if we
     // have to init their parts to zero
     vector<AddrRange> intlv_ranges;
     vector<AbstractMemory*> curr_memories;
     for (AddrRangeMap<AbstractMemory*>::const_iterator r = addrMap.begin();
          r != addrMap.end(); ++r) {
         // simply skip past all memories that are null and hence do
         // not need any backing store
         if (!r->second->isNull()) {
             // if the range is interleaved then save it for now
             if (r->first.interleaved()) {
                 // if we already got interleaved ranges that are not
                 // part of the same range, then first do a merge
                 // before we add the new one
                 if (!intlv_ranges.empty() &&
                     !intlv_ranges.back().mergesWith(r->first)) {
                     AddrRange merged_range(intlv_ranges);
                     createBackingStore(merged_range, curr_memories);
                     intlv_ranges.clear();
                     curr_memories.clear();
                 }
                 intlv_ranges.push_back(r->first);
                 curr_memories.push_back(r->second);
             } else {
                 vector<AbstractMemory*> single_memory;
                 single_memory.push_back(r->second);
                 createBackingStore(r->first, single_memory);
             }
         }
     }

     // if there is still interleaved ranges waiting to be merged, go
     // ahead and do it
     if (!intlv_ranges.empty()) {
         AddrRange merged_range(intlv_ranges);
         createBackingStore(merged_range, curr_memories);
     }
 }

 void
 PhysicalMemory::createBackingStore(AddrRange range,
                                    const vector<AbstractMemory*>& _memories)
 {
     if (range.interleaved())
         panic("Cannot create backing store for interleaved range %s\n",
               range.to_string());

     // perform the actual mmap
     DPRINTF(BusAddrRanges, "Creating backing store for range %s with size %d\n",
             range.to_string(), range.size());
     int map_flags = MAP_ANON | MAP_PRIVATE;
     uint8_t* pmem = (uint8_t*) mmap(NULL, range.size(),
                                     PROT_READ | PROT_WRITE,
                                     map_flags, -1, 0);

     if (pmem == (uint8_t*) MAP_FAILED) {
         perror("mmap");
         fatal("Could not mmap %d bytes for range %s!\n", range.size(),
               range.to_string());
     }

     // remember this backing store so we can checkpoint it and unmap
     // it appropriately
     backingStore.push_back(make_pair(range, pmem));

     // point the memories to their backing store, and if requested,
     // initialize the memory range to 0
     for (vector<AbstractMemory*>::const_iterator m = _memories.begin();
          m != _memories.end(); ++m) {
         DPRINTF(BusAddrRanges, "Mapping memory %s to backing store\n",
                 (*m)->name());
         (*m)->setBackingStore(pmem);
     }
 }

 PhysicalMemory::~PhysicalMemory()
 {
     // unmap the backing store
     for (vector<pair<AddrRange, uint8_t*> >::iterator s = backingStore.begin();
          s != backingStore.end(); ++s)
         munmap((char*)s->second, s->first.size());
 }

 bool
 PhysicalMemory::isMemAddr(Addr addr) const
 {
     // see if the address is within the last matched range
     if (!rangeCache.contains(addr)) {
         // lookup in the interval tree
         AddrRangeMap<AbstractMemory*>::const_iterator r = addrMap.find(addr);
         if (r == addrMap.end()) {
             // not in the cache, and not in the tree
             return false;
         }
         // the range is in the tree, update the cache
         rangeCache = r->first;
     }

     assert(addrMap.find(addr) != addrMap.end());

     // either matched the cache or found in the tree
     return true;
 }

 AddrRangeList
 PhysicalMemory::getConfAddrRanges() const
 {
     // this could be done once in the constructor, but since it is unlikely to
     // be called more than once the iteration should not be a problem
     AddrRangeList ranges;
     vector<AddrRange> intlv_ranges;
     for (AddrRangeMap<AbstractMemory*>::const_iterator r = addrMap.begin();
          r != addrMap.end(); ++r) {
         if (r->second->isConfReported()) {
             // if the range is interleaved then save it for now
             if (r->first.interleaved()) {
                 // if we already got interleaved ranges that are not
                 // part of the same range, then first do a merge
                 // before we add the new one
                 if (!intlv_ranges.empty() &&
                     !intlv_ranges.back().mergesWith(r->first)) {
                     ranges.push_back(AddrRange(intlv_ranges));
                     intlv_ranges.clear();
                 }
                 intlv_ranges.push_back(r->first);
             } else {
                 // keep the current range
                 ranges.push_back(r->first);
             }
         }
     }

     // if there is still interleaved ranges waiting to be merged,
     // go ahead and do it
     if (!intlv_ranges.empty()) {
         ranges.push_back(AddrRange(intlv_ranges));
     }

     return ranges;
 }

 void
 PhysicalMemory::access(PacketPtr pkt)
 {
     assert(pkt->isRequest());
     Addr addr = pkt->getAddr();
     AddrRangeMap<AbstractMemory*>::const_iterator m = addrMap.find(addr);
     assert(m != addrMap.end());
     m->second->access(pkt);
 }

 void
 PhysicalMemory::functionalAccess(PacketPtr pkt)
 {
     assert(pkt->isRequest());
     Addr addr = pkt->getAddr();
     AddrRangeMap<AbstractMemory*>::const_iterator m = addrMap.find(addr);
     assert(m != addrMap.end());
     m->second->functionalAccess(pkt);
 }

 void
 PhysicalMemory::serialize(ostream& os)
 {
     // serialize all the locked addresses and their context ids
     vector<Addr> lal_addr;
     vector<int> lal_cid;

     for (vector<AbstractMemory*>::iterator m = memories.begin();
          m != memories.end(); ++m) {
         const list<LockedAddr>& locked_addrs = (*m)->getLockedAddrList();
         for (list<LockedAddr>::const_iterator l = locked_addrs.begin();
              l != locked_addrs.end(); ++l) {
             lal_addr.push_back(l->addr);
             lal_cid.push_back(l->contextId);
         }
     }

     arrayParamOut(os, "lal_addr", lal_addr);
     arrayParamOut(os, "lal_cid", lal_cid);

     // serialize the backing stores
     unsigned int nbr_of_stores = backingStore.size();
     SERIALIZE_SCALAR(nbr_of_stores);

     unsigned int store_id = 0;
     // store each backing store memory segment in a file
     for (vector<pair<AddrRange, uint8_t*> >::iterator s = backingStore.begin();
          s != backingStore.end(); ++s) {
         nameOut(os, csprintf("%s.store%d", name(), store_id));
         serializeStore(os, store_id++, s->first, s->second);
     }
 }

 void
 PhysicalMemory::serializeStore(ostream& os, unsigned int store_id,
                                AddrRange range, uint8_t* pmem)
 {
     // we cannot use the address range for the name as the
     // memories that are not part of the address map can overlap
     string filename = name() + ".store" + to_string(store_id) + ".pmem";
     long range_size = range.size();

     DPRINTF(Checkpoint, "Serializing physical memory %s with size %d\n",
             filename, range_size);

     SERIALIZE_SCALAR(store_id);
     SERIALIZE_SCALAR(filename);
     SERIALIZE_SCALAR(range_size);

     // write memory file
     string filepath = Checkpoint::dir() + "/" + filename.c_str();
     int fd = creat(filepath.c_str(), 0664);
     if (fd < 0) {
         perror("creat");
         fatal("Can't open physical memory checkpoint file '%s'\n",
               filename);
     }

     gzFile compressed_mem = gzdopen(fd, "wb");
     if (compressed_mem == NULL)
         fatal("Insufficient memory to allocate compression state for %s\n",
               filename);

     uint64_t pass_size = 0;

     // gzwrite fails if (int)len < 0 (gzwrite returns int)
     for (uint64_t written = 0; written < range.size();
          written += pass_size) {
         pass_size = (uint64_t)INT_MAX < (range.size() - written) ?
             (uint64_t)INT_MAX : (range.size() - written);

         if (gzwrite(compressed_mem, pmem + written,
                     (unsigned int) pass_size) != (int) pass_size) {
             fatal("Write failed on physical memory checkpoint file '%s'\n",
                   filename);
         }
     }

     // close the compressed stream and check that the exit status
     // is zero
     if (gzclose(compressed_mem))
         fatal("Close failed on physical memory checkpoint file '%s'\n",
               filename);

 }

 void
 PhysicalMemory::unserialize(Checkpoint* cp, const string& section)
 {
     // unserialize the locked addresses and map them to the
     // appropriate memory controller
     vector<Addr> lal_addr;
     vector<int> lal_cid;
     arrayParamIn(cp, section, "lal_addr", lal_addr);
     arrayParamIn(cp, section, "lal_cid", lal_cid);
     for(size_t i = 0; i < lal_addr.size(); ++i) {
         AddrRangeMap<AbstractMemory*>::const_iterator m =
             addrMap.find(lal_addr[i]);
         m->second->addLockedAddr(LockedAddr(lal_addr[i], lal_cid[i]));
     }

     // unserialize the backing stores
     unsigned int nbr_of_stores;
     UNSERIALIZE_SCALAR(nbr_of_stores);

     for (unsigned int i = 0; i < nbr_of_stores; ++i) {
         unserializeStore(cp, csprintf("%s.store%d", section, i));
     }

 }

 void
 PhysicalMemory::unserializeStore(Checkpoint* cp, const string& section)
 {
     const uint32_t chunk_size = 16384;

     unsigned int store_id;
     UNSERIALIZE_SCALAR(store_id);

     string filename;
     UNSERIALIZE_SCALAR(filename);
     string filepath = cp->cptDir + "/" + filename;

     // mmap memoryfile
     int fd = open(filepath.c_str(), O_RDONLY);
     if (fd < 0) {
         perror("open");
         fatal("Can't open physical memory checkpoint file '%s'", filename);
     }

     gzFile compressed_mem = gzdopen(fd, "rb");
     if (compressed_mem == NULL)
         fatal("Insufficient memory to allocate compression state for %s\n",
               filename);

     uint8_t* pmem = backingStore[store_id].second;
     AddrRange range = backingStore[store_id].first;

     // unmap file that was mmapped in the constructor, this is
     // done here to make sure that gzip and open don't muck with
     // our nice large space of memory before we reallocate it
     munmap((char*) pmem, range.size());

     long range_size;
     UNSERIALIZE_SCALAR(range_size);

     DPRINTF(Checkpoint, "Unserializing physical memory %s with size %d\n",
             filename, range_size);

     if (range_size != range.size())
         fatal("Memory range size has changed! Saw %lld, expected %lld\n",
               range_size, range.size());

     pmem = (uint8_t*) mmap(NULL, range.size(), PROT_READ | PROT_WRITE,
                            MAP_ANON | MAP_PRIVATE, -1, 0);

     if (pmem == (void*) MAP_FAILED) {
         perror("mmap");
         fatal("Could not mmap physical memory!\n");
     }

     uint64_t curr_size = 0;
     long* temp_page = new long[chunk_size];
     long* pmem_current;
     uint32_t bytes_read;
     while (curr_size < range.size()) {
         bytes_read = gzread(compressed_mem, temp_page, chunk_size);
         if (bytes_read == 0)
             break;

         assert(bytes_read % sizeof(long) == 0);

         for (uint32_t x = 0; x < bytes_read / sizeof(long); x++) {
             // Only copy bytes that are non-zero, so we don't give
             // the VM system hell
             if (*(temp_page + x) != 0) {
                 pmem_current = (long*)(pmem + curr_size + x * sizeof(long));
                 *pmem_current = *(temp_page + x);
             }
         }
         curr_size += bytes_read;
     }

     delete[] temp_page;

     if (gzclose(compressed_mem))
         fatal("Close failed on physical memory checkpoint file '%s'\n",
               filename);
 }
	/*
	* Copyright (c) 2012 ARM Limited
	* All rights reserved
	*
	* The license below extends only to copyright in the software and shall
	* not be construed as granting a license to any other intellectual
	* property including but not limited to intellectual property relating
	* to a hardware implementation of the functionality of the software
	* licensed hereunder. You may use the software subject to the license
	* terms below provided that you ensure that this notice is replicated
	* unmodified and in its entirety in all distributions of the software,
	* modified or unmodified, in source code or in binary form.
	*
	* Redistribution and use in source and binary forms, with or without
	* modification, are permitted provided that the following conditions are
	* met: redistributions of source code must retain the above copyright
	* notice, this list of conditions and the following disclaimer;
	* redistributions in binary form must reproduce the above copyright
	* notice, this list of conditions and the following disclaimer in the
	* documentation and/or other materials provided with the distribution;
	* neither the name of the copyright holders nor the names of its
	* contributors may be used to endorse or promote products derived from
	* this software without specific prior written permission.
	*
	* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
	* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
	* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
	* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
	* OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
	* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
	* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
	* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
	* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
	* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
	* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
	*
	* Authors: Andreas Hansson
	*/

	#include <sys/mman.h>
	#include <sys/types.h>
	#include <sys/user.h>
	#include <fcntl.h>
	#include <unistd.h>
	#include <zlib.h>

	#include <cerrno>
	#include <climits>
	#include <cstdio>
	#include <iostream>
	#include <string>

	#include "base/trace.hh"
	#include "debug/BusAddrRanges.hh"
	#include "debug/Checkpoint.hh"
	#include "mem/abstract_mem.hh"
	#include "mem/physical.hh"

	using namespace std;

	PhysicalMemory::PhysicalMemory(const string& _name,
	const vector<AbstractMemory*>& _memories) :
	_name(_name), size(0)
	{
	// add the memories from the system to the address map as
	// appropriate
	for (vector<AbstractMemory*>::const_iterator m = _memories.begin();
	m != _memories.end(); ++m) {
	// only add the memory if it is part of the global address map
	if ((*m)->isInAddrMap()) {
	memories.push_back(*m);

	// calculate the total size once and for all
	size += (*m)->size();

	// add the range to our interval tree and make sure it does not
	// intersect an existing range
	if (addrMap.insert((m)->getAddrRange(), m) == addrMap.end())
	fatal("Memory address range for %s is overlapping\n",
	(*m)->name());
	} else {
	DPRINTF(BusAddrRanges,
	"Skipping memory %s that is not in global address map\n",
	(*m)->name());
	// this type of memory is used e.g. as reference memory by
	// Ruby, and they also needs a backing store, but should
	// not be part of the global address map

	// simply do it independently, also note that this kind of
	// memories are allowed to overlap in the logic address
	// map
	vector<AbstractMemory*> unmapped_mems;
	unmapped_mems.push_back(*m);
	createBackingStore((*m)->getAddrRange(), unmapped_mems);
	}
	}

	// iterate over the increasing addresses and chunks of contigous
	// space to be mapped to backing store, also remember what
	// memories constitute the range so we can go and find out if we
	// have to init their parts to zero
	vector<AddrRange> intlv_ranges;
	vector<AbstractMemory*> curr_memories;
	for (AddrRangeMap<AbstractMemory*>::const_iterator r = addrMap.begin();
	r != addrMap.end(); ++r) {
	// simply skip past all memories that are null and hence do
	// not need any backing store
	if (!r->second->isNull()) {
	// if the range is interleaved then save it for now
	if (r->first.interleaved()) {
	// if we already got interleaved ranges that are not
	// part of the same range, then first do a merge
	// before we add the new one
	if (!intlv_ranges.empty() &&
	!intlv_ranges.back().mergesWith(r->first)) {
	AddrRange merged_range(intlv_ranges);
	createBackingStore(merged_range, curr_memories);
	intlv_ranges.clear();
	curr_memories.clear();
	}
	intlv_ranges.push_back(r->first);
	curr_memories.push_back(r->second);
	} else {
	vector<AbstractMemory*> single_memory;
	single_memory.push_back(r->second);
	createBackingStore(r->first, single_memory);
	}
	}
	}

	// if there is still interleaved ranges waiting to be merged, go
	// ahead and do it
	if (!intlv_ranges.empty()) {
	AddrRange merged_range(intlv_ranges);
	createBackingStore(merged_range, curr_memories);
	}
	}

	void
	PhysicalMemory::createBackingStore(AddrRange range,
	const vector<AbstractMemory*>& _memories)
	{
	if (range.interleaved())
	panic("Cannot create backing store for interleaved range %s\n",
	range.to_string());

	// perform the actual mmap
	DPRINTF(BusAddrRanges, "Creating backing store for range %s with size %d\n",
	range.to_string(), range.size());
	int map_flags = MAP_ANON \| MAP_PRIVATE;
	uint8_t* pmem = (uint8_t*) mmap(NULL, range.size(),
	PROT_READ \| PROT_WRITE,
	map_flags, -1, 0);

	if (pmem == (uint8_t*) MAP_FAILED) {
	perror("mmap");
	fatal("Could not mmap %d bytes for range %s!\n", range.size(),
	range.to_string());
	}

	// remember this backing store so we can checkpoint it and unmap
	// it appropriately
	backingStore.push_back(make_pair(range, pmem));

	// point the memories to their backing store, and if requested,
	// initialize the memory range to 0
	for (vector<AbstractMemory*>::const_iterator m = _memories.begin();
	m != _memories.end(); ++m) {
	DPRINTF(BusAddrRanges, "Mapping memory %s to backing store\n",
	(*m)->name());
	(*m)->setBackingStore(pmem);
	}
	}

	PhysicalMemory::~PhysicalMemory()
	{
	// unmap the backing store
	for (vector<pair<AddrRange, uint8_t*> >::iterator s = backingStore.begin();
	s != backingStore.end(); ++s)
	munmap((char*)s->second, s->first.size());
	}

	bool
	PhysicalMemory::isMemAddr(Addr addr) const
	{
	// see if the address is within the last matched range
	if (!rangeCache.contains(addr)) {
	// lookup in the interval tree
	AddrRangeMap<AbstractMemory*>::const_iterator r = addrMap.find(addr);
	if (r == addrMap.end()) {
	// not in the cache, and not in the tree
	return false;
	}
	// the range is in the tree, update the cache
	rangeCache = r->first;
	}

	assert(addrMap.find(addr) != addrMap.end());

	// either matched the cache or found in the tree
	return true;
	}

	AddrRangeList
	PhysicalMemory::getConfAddrRanges() const
	{
	// this could be done once in the constructor, but since it is unlikely to
	// be called more than once the iteration should not be a problem
	AddrRangeList ranges;
	vector<AddrRange> intlv_ranges;
	for (AddrRangeMap<AbstractMemory*>::const_iterator r = addrMap.begin();
	r != addrMap.end(); ++r) {
	if (r->second->isConfReported()) {
	// if the range is interleaved then save it for now
	if (r->first.interleaved()) {
	// if we already got interleaved ranges that are not
	// part of the same range, then first do a merge
	// before we add the new one
	if (!intlv_ranges.empty() &&
	!intlv_ranges.back().mergesWith(r->first)) {
	ranges.push_back(AddrRange(intlv_ranges));
	intlv_ranges.clear();
	}
	intlv_ranges.push_back(r->first);
	} else {
	// keep the current range
	ranges.push_back(r->first);
	}
	}
	}

	// if there is still interleaved ranges waiting to be merged,
	// go ahead and do it
	if (!intlv_ranges.empty()) {
	ranges.push_back(AddrRange(intlv_ranges));
	}

	return ranges;
	}

	void
	PhysicalMemory::access(PacketPtr pkt)
	{
	assert(pkt->isRequest());
	Addr addr = pkt->getAddr();
	AddrRangeMap<AbstractMemory*>::const_iterator m = addrMap.find(addr);
	assert(m != addrMap.end());
	m->second->access(pkt);
	}

	void
	PhysicalMemory::functionalAccess(PacketPtr pkt)
	{
	assert(pkt->isRequest());
	Addr addr = pkt->getAddr();
	AddrRangeMap<AbstractMemory*>::const_iterator m = addrMap.find(addr);
	assert(m != addrMap.end());
	m->second->functionalAccess(pkt);
	}

	void
	PhysicalMemory::serialize(ostream& os)
	{
	// serialize all the locked addresses and their context ids
	vector<Addr> lal_addr;
	vector<int> lal_cid;

	for (vector<AbstractMemory*>::iterator m = memories.begin();
	m != memories.end(); ++m) {
	const list<LockedAddr>& locked_addrs = (*m)->getLockedAddrList();
	for (list<LockedAddr>::const_iterator l = locked_addrs.begin();
	l != locked_addrs.end(); ++l) {
	lal_addr.push_back(l->addr);
	lal_cid.push_back(l->contextId);
	}
	}

	arrayParamOut(os, "lal_addr", lal_addr);
	arrayParamOut(os, "lal_cid", lal_cid);

	// serialize the backing stores
	unsigned int nbr_of_stores = backingStore.size();
	SERIALIZE_SCALAR(nbr_of_stores);

	unsigned int store_id = 0;
	// store each backing store memory segment in a file
	for (vector<pair<AddrRange, uint8_t*> >::iterator s = backingStore.begin();
	s != backingStore.end(); ++s) {
	nameOut(os, csprintf("%s.store%d", name(), store_id));
	serializeStore(os, store_id++, s->first, s->second);
	}
	}

	void
	PhysicalMemory::serializeStore(ostream& os, unsigned int store_id,
	AddrRange range, uint8_t* pmem)
	{
	// we cannot use the address range for the name as the
	// memories that are not part of the address map can overlap
	string filename = name() + ".store" + to_string(store_id) + ".pmem";
	long range_size = range.size();

	DPRINTF(Checkpoint, "Serializing physical memory %s with size %d\n",
	filename, range_size);

	SERIALIZE_SCALAR(store_id);
	SERIALIZE_SCALAR(filename);
	SERIALIZE_SCALAR(range_size);

	// write memory file
	string filepath = Checkpoint::dir() + "/" + filename.c_str();
	int fd = creat(filepath.c_str(), 0664);
	if (fd < 0) {
	perror("creat");
	fatal("Can't open physical memory checkpoint file '%s'\n",
	filename);
	}

	gzFile compressed_mem = gzdopen(fd, "wb");
	if (compressed_mem == NULL)
	fatal("Insufficient memory to allocate compression state for %s\n",
	filename);

	uint64_t pass_size = 0;

	// gzwrite fails if (int)len < 0 (gzwrite returns int)
	for (uint64_t written = 0; written < range.size();
	written += pass_size) {
	pass_size = (uint64_t)INT_MAX < (range.size() - written) ?
	(uint64_t)INT_MAX : (range.size() - written);

	if (gzwrite(compressed_mem, pmem + written,
	(unsigned int) pass_size) != (int) pass_size) {
	fatal("Write failed on physical memory checkpoint file '%s'\n",
	filename);
	}
	}

	// close the compressed stream and check that the exit status
	// is zero
	if (gzclose(compressed_mem))
	fatal("Close failed on physical memory checkpoint file '%s'\n",
	filename);

	}

	void
	PhysicalMemory::unserialize(Checkpoint* cp, const string& section)
	{
	// unserialize the locked addresses and map them to the
	// appropriate memory controller
	vector<Addr> lal_addr;
	vector<int> lal_cid;
	arrayParamIn(cp, section, "lal_addr", lal_addr);
	arrayParamIn(cp, section, "lal_cid", lal_cid);
	for(size_t i = 0; i < lal_addr.size(); ++i) {
	AddrRangeMap<AbstractMemory*>::const_iterator m =
	addrMap.find(lal_addr[i]);
	m->second->addLockedAddr(LockedAddr(lal_addr[i], lal_cid[i]));
	}

	// unserialize the backing stores
	unsigned int nbr_of_stores;
	UNSERIALIZE_SCALAR(nbr_of_stores);

	for (unsigned int i = 0; i < nbr_of_stores; ++i) {
	unserializeStore(cp, csprintf("%s.store%d", section, i));
	}

	}

	void
	PhysicalMemory::unserializeStore(Checkpoint* cp, const string& section)
	{
	const uint32_t chunk_size = 16384;

	unsigned int store_id;
	UNSERIALIZE_SCALAR(store_id);

	string filename;
	UNSERIALIZE_SCALAR(filename);
	string filepath = cp->cptDir + "/" + filename;

	// mmap memoryfile
	int fd = open(filepath.c_str(), O_RDONLY);
	if (fd < 0) {
	perror("open");
	fatal("Can't open physical memory checkpoint file '%s'", filename);
	}

	gzFile compressed_mem = gzdopen(fd, "rb");
	if (compressed_mem == NULL)
	fatal("Insufficient memory to allocate compression state for %s\n",
	filename);

	uint8_t* pmem = backingStore[store_id].second;
	AddrRange range = backingStore[store_id].first;

	// unmap file that was mmapped in the constructor, this is
	// done here to make sure that gzip and open don't muck with
	// our nice large space of memory before we reallocate it
	munmap((char*) pmem, range.size());

	long range_size;
	UNSERIALIZE_SCALAR(range_size);

	DPRINTF(Checkpoint, "Unserializing physical memory %s with size %d\n",
	filename, range_size);

	if (range_size != range.size())
	fatal("Memory range size has changed! Saw %lld, expected %lld\n",
	range_size, range.size());

	pmem = (uint8_t*) mmap(NULL, range.size(), PROT_READ \| PROT_WRITE,
	MAP_ANON \| MAP_PRIVATE, -1, 0);

	if (pmem == (void*) MAP_FAILED) {
	perror("mmap");
	fatal("Could not mmap physical memory!\n");
	}

	uint64_t curr_size = 0;
	long* temp_page = new long[chunk_size];
	long* pmem_current;
	uint32_t bytes_read;
	while (curr_size < range.size()) {
	bytes_read = gzread(compressed_mem, temp_page, chunk_size);
	if (bytes_read == 0)
	break;

	assert(bytes_read % sizeof(long) == 0);

	for (uint32_t x = 0; x < bytes_read / sizeof(long); x++) {
	// Only copy bytes that are non-zero, so we don't give
	// the VM system hell
	if (*(temp_page + x) != 0) {
	pmem_current = (long)(pmem + curr_size + x sizeof(long));
	pmem_current = (temp_page + x);
	}
	}
	curr_size += bytes_read;
	}

	delete[] temp_page;

	if (gzclose(compressed_mem))
	fatal("Close failed on physical memory checkpoint file '%s'\n",
	filename);
	}