gem5/src/mem/physical.cc

/*
 * Copyright (c) 2012, 2014, 2018 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,
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 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

#include "mem/physical.hh"

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

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

#include "base/trace.hh"
#include "debug/AddrRanges.hh"
#include "debug/Checkpoint.hh"
#include "mem/abstract_mem.hh"
#include "sim/serialize.hh"

/**
 * On Linux, MAP_NORESERVE allow us to simulate a very large memory
 * without committing to actually providing the swap space on the
 * host. On FreeBSD or OSX the MAP_NORESERVE flag does not exist,
 * so simply make it 0.
 */
#if defined(__APPLE__) || defined(__FreeBSD__)
#ifndef MAP_NORESERVE
#define MAP_NORESERVE 0
#endif
#endif

namespace gem5
{

namespace memory
{

PhysicalMemory::PhysicalMemory(const std::string& _name,
                               const std::vector<AbstractMemory*>& _memories,
                               bool mmap_using_noreserve,
                               const std::string& shared_backstore) :
    _name(_name), size(0), mmapUsingNoReserve(mmap_using_noreserve),
    sharedBackstore(shared_backstore), sharedBackstoreSize(0)
{
    if (mmap_using_noreserve)
        warn("Not reserving swap space. May cause SIGSEGV on actual usage\n");

    // add the memories from the system to the address map as
    // appropriate
    for (const auto& m : _memories) {
        // 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
            fatal_if(addrMap.insert(m->getAddrRange(), m) == addrMap.end(),
                     "Memory address range for %s is overlapping\n",
                     m->name());
        } else {
            // 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
            DPRINTF(AddrRanges,
                    "Skipping memory %s that is not in global address map\n",
                    m->name());

            // sanity check
            fatal_if(m->getAddrRange().interleaved(),
                     "Memory %s that is not in the global address map cannot "
                     "be interleaved\n", m->name());

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

    // iterate over the increasing addresses and chunks of contiguous
    // space to be mapped to backing store, create it and inform the
    // memories
    std::vector<AddrRange> intlv_ranges;
    std::vector<AbstractMemory*> curr_memories;
    for (const auto& r : addrMap) {
        // 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);

                    AbstractMemory *f = curr_memories.front();
                    for (const auto& c : curr_memories)
                        if (f->isConfReported() != c->isConfReported() ||
                            f->isInAddrMap() != c->isInAddrMap() ||
                            f->isKvmMap() != c->isKvmMap())
                            fatal("Inconsistent flags in an interleaved "
                                  "range\n");

                    createBackingStore(merged_range, curr_memories,
                                       f->isConfReported(), f->isInAddrMap(),
                                       f->isKvmMap());

                    intlv_ranges.clear();
                    curr_memories.clear();
                }
                intlv_ranges.push_back(r.first);
                curr_memories.push_back(r.second);
            } else {
                std::vector<AbstractMemory*> single_memory{r.second};
                createBackingStore(r.first, single_memory,
                                   r.second->isConfReported(),
                                   r.second->isInAddrMap(),
                                   r.second->isKvmMap());
            }
        }
    }

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

        AbstractMemory *f = curr_memories.front();
        for (const auto& c : curr_memories)
            if (f->isConfReported() != c->isConfReported() ||
                f->isInAddrMap() != c->isInAddrMap() ||
                f->isKvmMap() != c->isKvmMap())
                fatal("Inconsistent flags in an interleaved "
                      "range\n");

        createBackingStore(merged_range, curr_memories,
                           f->isConfReported(), f->isInAddrMap(),
                           f->isKvmMap());
    }
}

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

    // perform the actual mmap
    DPRINTF(AddrRanges, "Creating backing store for range %s with size %d\n",
            range.to_string(), range.size());

    int shm_fd;
    int map_flags;
    off_t map_offset;

    if (sharedBackstore.empty()) {
        shm_fd = -1;
        map_flags =  MAP_ANON | MAP_PRIVATE;
        map_offset = 0;
    } else {
        // Newly create backstore will be located after previous one.
        map_offset = sharedBackstoreSize;
        sharedBackstoreSize += range.size();
        DPRINTF(AddrRanges, "Sharing backing store as %s at offset %llu\n",
                sharedBackstore.c_str(), (uint64_t)map_offset);
        shm_fd = shm_open(sharedBackstore.c_str(), O_CREAT | O_RDWR, 0666);
        if (shm_fd == -1)
               panic("Shared memory failed");
        if (ftruncate(shm_fd, sharedBackstoreSize))
               panic("Setting size of shared memory failed");
        map_flags = MAP_SHARED;
    }

    // to be able to simulate very large memories, the user can opt to
    // pass noreserve to mmap
    if (mmapUsingNoReserve) {
        map_flags |= MAP_NORESERVE;
    }

    uint8_t* pmem = (uint8_t*) mmap(NULL, range.size(),
                                    PROT_READ | PROT_WRITE,
                                    map_flags, shm_fd, map_offset);

    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.emplace_back(range, pmem,
                              conf_table_reported, in_addr_map, kvm_map);

    // point the memories to their backing store
    for (const auto& m : _memories) {
        DPRINTF(AddrRanges, "Mapping memory %s to backing store\n",
                m->name());
        m->setBackingStore(pmem);
    }
}

PhysicalMemory::~PhysicalMemory()
{
    // unmap the backing store
    for (auto& s : backingStore)
        munmap((char*)s.pmem, s.range.size());
}

bool
PhysicalMemory::isMemAddr(Addr addr) const
{
    return addrMap.contains(addr) != addrMap.end();
}

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;
    std::vector<AddrRange> intlv_ranges;
    for (const auto& r : addrMap) {
        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());
    const auto& m = addrMap.contains(pkt->getAddrRange());
    assert(m != addrMap.end());
    m->second->access(pkt);
}

void
PhysicalMemory::functionalAccess(PacketPtr pkt)
{
    assert(pkt->isRequest());
    const auto& m = addrMap.contains(pkt->getAddrRange());
    assert(m != addrMap.end());
    m->second->functionalAccess(pkt);
}

void
PhysicalMemory::serialize(CheckpointOut &cp) const
{
    // serialize all the locked addresses and their context ids
    std::vector<Addr> lal_addr;
    std::vector<ContextID> lal_cid;

    for (auto& m : memories) {
        const std::list<LockedAddr>& locked_addrs = m->getLockedAddrList();
        for (const auto& l : locked_addrs) {
            lal_addr.push_back(l.addr);
            lal_cid.push_back(l.contextId);
        }
    }

    SERIALIZE_CONTAINER(lal_addr);
    SERIALIZE_CONTAINER(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 (auto& s : backingStore) {
        ScopedCheckpointSection sec(cp, csprintf("store%d", store_id));
        serializeStore(cp, store_id++, s.range, s.pmem);
    }
}

void
PhysicalMemory::serializeStore(CheckpointOut &cp, unsigned int store_id,
                               AddrRange range, uint8_t* pmem) const
{
    // we cannot use the address range for the name as the
    // memories that are not part of the address map can overlap
    std::string filename =
        name() + ".store" + std::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
    std::string filepath = CheckpointIn::dir() + "/" + filename.c_str();
    gzFile compressed_mem = gzopen(filepath.c_str(), "wb");
    if (compressed_mem == NULL)
        fatal("Can't open physical memory checkpoint file '%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(CheckpointIn &cp)
{
    // unserialize the locked addresses and map them to the
    // appropriate memory controller
    std::vector<Addr> lal_addr;
    std::vector<ContextID> lal_cid;
    UNSERIALIZE_CONTAINER(lal_addr);
    UNSERIALIZE_CONTAINER(lal_cid);
    for (size_t i = 0; i < lal_addr.size(); ++i) {
        const auto& m = addrMap.contains(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) {
        ScopedCheckpointSection sec(cp, csprintf("store%d", i));
        unserializeStore(cp);
    }

}

void
PhysicalMemory::unserializeStore(CheckpointIn &cp)
{
    const uint32_t chunk_size = 16384;

    unsigned int store_id;
    UNSERIALIZE_SCALAR(store_id);

    std::string filename;
    UNSERIALIZE_SCALAR(filename);
    std::string filepath = cp.getCptDir() + "/" + filename;

    // mmap memoryfile
    gzFile compressed_mem = gzopen(filepath.c_str(), "rb");
    if (compressed_mem == NULL)
        fatal("Can't open physical memory checkpoint file '%s'", filename);

    // we've already got the actual backing store mapped
    uint8_t* pmem = backingStore[store_id].pmem;
    AddrRange range = backingStore[store_id].range;

    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());

    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);
}

} // namespace memory
} // namespace gem5