mem_state.cc

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/*
 * Copyright (c) 2017-2020 Advanced Micro Devices, Inc.
 * All rights reserved.
 *
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 * 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
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 * this software without specific prior written permission.
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 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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#include "sim/mem_state.hh"
 
#include <cassert>
 
#include "arch/generic/mmu.hh"
#include "debug/Vma.hh"
#include "mem/se_translating_port_proxy.hh"
#include "sim/process.hh"
#include "sim/syscall_debug_macros.hh"
#include "sim/system.hh"
#include "sim/vma.hh"
 
namespace gem5
{
 
MemState::MemState(Process *owner, Addr brk_point, Addr stack_base,
                   Addr max_stack_size, Addr next_thread_stack_base,
                   Addr mmap_end)
    : _ownerProcess(owner),
      _pageBytes(owner->pTable->pageSize()), _brkPoint(brk_point),
      _stackBase(stack_base), _stackSize(max_stack_size),
      _maxStackSize(max_stack_size), _stackMin(stack_base - max_stack_size),
      _nextThreadStackBase(next_thread_stack_base),
      _mmapEnd(mmap_end), _endBrkPoint(brk_point)
{
}
 
MemState&
MemState::operator=(const MemState &in)
{
    if (this == &in)
        return *this;
 
    _pageBytes = in._pageBytes;
    _brkPoint = in._brkPoint;
    _stackBase = in._stackBase;
    _stackSize = in._stackSize;
    _maxStackSize = in._maxStackSize;
    _stackMin = in._stackMin;
    _nextThreadStackBase = in._nextThreadStackBase;
    _mmapEnd = in._mmapEnd;
    _endBrkPoint = in._endBrkPoint;
    _vmaList = in._vmaList; /* This assignment does a deep copy. */
 
    return *this;
}
 
void
MemState::resetOwner(Process *owner)
{
    _ownerProcess = owner;
}
 
bool
MemState::isUnmapped(Addr start_addr, Addr length)
{
    Addr end_addr = start_addr + length;
    const AddrRange range(start_addr, end_addr);
    for (const auto &vma : _vmaList) {
        if (vma.intersects(range))
            return false;
    }
 
    for (auto start = start_addr; start < end_addr;
         start += _pageBytes) {
        if (_ownerProcess->pTable->lookup(start) != nullptr) {
            panic("Someone allocated physical memory at VA %p without "
                  "creating a VMA!\n", start);
            return false;
        }
    }
    return true;
}
 
void
MemState::updateBrkRegion(Addr old_brk, Addr new_brk)
{
    if (new_brk < old_brk) {
        _brkPoint = new_brk;
        return;
    }
 
    auto page_aligned_brk = roundUp(new_brk, _pageBytes);
 
    if (page_aligned_brk > _endBrkPoint) {
        auto length = page_aligned_brk - _endBrkPoint;
        if (!isUnmapped(_endBrkPoint, length)) {
            return;
        }
 
        mapRegion(_endBrkPoint, length, "heap");
        _endBrkPoint = page_aligned_brk;
    }
 
    _brkPoint = new_brk;
}
 
void
MemState::mapRegion(Addr start_addr, Addr length,
                    const std::string& region_name, int sim_fd, Addr offset)
{
    DPRINTF(Vma, "memstate: creating vma (%s) [0x%x - 0x%x]\n",
            region_name.c_str(), start_addr, start_addr + length);
 
    assert(isUnmapped(start_addr, length));
 
    _vmaList.emplace_back(AddrRange(start_addr, start_addr + length),
                          _pageBytes, region_name, sim_fd, offset);
}
 
void
MemState::unmapRegion(Addr start_addr, Addr length)
{
    Addr end_addr = start_addr + length;
    const AddrRange range(start_addr, end_addr);
 
    auto vma = std::begin(_vmaList);
    while (vma != std::end(_vmaList)) {
        if (vma->isStrictSuperset(range)) {
            DPRINTF(Vma, "memstate: split vma [0x%x - 0x%x] into "
                    "[0x%x - 0x%x] and [0x%x - 0x%x]\n",
                    vma->start(), vma->end(),
                    vma->start(), start_addr,
                    end_addr, vma->end());
            _vmaList.push_back(*vma);
            _vmaList.back().sliceRegionRight(start_addr);
 
            vma->sliceRegionLeft(end_addr);
 
            break;
        } else if (vma->isSubset(range)) {
            DPRINTF(Vma, "memstate: destroying vma [0x%x - 0x%x]\n",
                    vma->start(), vma->end());
            vma = _vmaList.erase(vma);
 
            continue;
 
        } else if (vma->intersects(range)) {
            if (vma->start() < start_addr) {
                DPRINTF(Vma, "memstate: resizing vma [0x%x - 0x%x] "
                        "into [0x%x - 0x%x]\n",
                        vma->start(), vma->end(),
                        vma->start(), start_addr);
                vma->sliceRegionRight(start_addr);
            } else {
                DPRINTF(Vma, "memstate: resizing vma [0x%x - 0x%x] "
                        "into [0x%x - 0x%x]\n",
                        vma->start(), vma->end(),
                        end_addr, vma->end());
                vma->sliceRegionLeft(end_addr);
            }
        }
 
        vma++;
    }
 
    for (auto *tc: _ownerProcess->system->threads) {
        tc->getMMUPtr()->flushAll();
    }
 
    do {
        if (!_ownerProcess->pTable->isUnmapped(start_addr, _pageBytes))
            _ownerProcess->pTable->unmap(start_addr, _pageBytes);
 
        start_addr += _pageBytes;
 
        length -= _pageBytes;
    } while (length > 0);
}
 
void
MemState::remapRegion(Addr start_addr, Addr new_start_addr, Addr length)
{
    Addr end_addr = start_addr + length;
    const AddrRange range(start_addr, end_addr);
 
    auto vma = std::begin(_vmaList);
    while (vma != std::end(_vmaList)) {
        if (vma->isStrictSuperset(range)) {
            _vmaList.push_back(*vma);
            _vmaList.back().sliceRegionRight(start_addr);
 
            _vmaList.push_back(*vma);
            _vmaList.back().sliceRegionLeft(end_addr);
 
            vma->sliceRegionLeft(start_addr);
            vma->sliceRegionRight(end_addr);
            vma->remap(new_start_addr);
 
            break;
        } else if (vma->isSubset(range)) {
            vma->remap(vma->start() - start_addr + new_start_addr);
        } else if (vma->intersects(range)) {
            _vmaList.push_back(*vma);
 
            if (vma->start() < start_addr) {
                _vmaList.back().sliceRegionRight(start_addr);
 
                vma->sliceRegionLeft(start_addr);
                vma->remap(new_start_addr);
            } else {
                _vmaList.back().sliceRegionLeft(end_addr);
 
                vma->sliceRegionRight(end_addr);
                vma->remap(new_start_addr + vma->start() - start_addr);
            }
        }
 
        vma++;
    }
 
    for (auto *tc: _ownerProcess->system->threads) {
        tc->getMMUPtr()->flushAll();
    }
 
    do {
        if (!_ownerProcess->pTable->isUnmapped(start_addr, _pageBytes))
            _ownerProcess->pTable->remap(start_addr, _pageBytes,
                                         new_start_addr);
 
        start_addr += _pageBytes;
        new_start_addr += _pageBytes;
 
        length -= _pageBytes;
    } while (length > 0);
}
 
bool
MemState::fixupFault(Addr vaddr)
{
    for (const auto &vma : _vmaList) {
        if (vma.contains(vaddr)) {
            Addr vpage_start = roundDown(vaddr, _pageBytes);
            _ownerProcess->allocateMem(vpage_start, _pageBytes);
 
            if (vma.hasHostBuf()) {
                for (auto &cid : _ownerProcess->contextIds) {
                    auto *tc = _ownerProcess->system->threads[cid];
                    SETranslatingPortProxy
                        virt_mem(tc, SETranslatingPortProxy::Always);
                    vma.fillMemPages(vpage_start, _pageBytes, virt_mem);
                }
            }
            return true;
        }
    }
 
    if (vaddr >= _stackMin && vaddr < _stackBase) {
        _ownerProcess->allocateMem(roundDown(vaddr, _pageBytes), _pageBytes);
        return true;
    }
 
    if (vaddr < _stackMin && vaddr >= _stackBase - _maxStackSize) {
        while (vaddr < _stackMin) {
            _stackMin -= _pageBytes;
            if (_stackBase - _stackMin > _maxStackSize) {
                fatal("Maximum stack size exceeded\n");
            }
            _ownerProcess->allocateMem(_stackMin, _pageBytes);
            inform("Increasing stack size by one page.");
        }
        return true;
    }
 
    return false;
}
 
Addr
MemState::extendMmap(Addr length)
{
    Addr start = _mmapEnd;
 
    if (_ownerProcess->mmapGrowsDown())
        start = _mmapEnd - length;
 
    // Look for a contiguous region of free virtual memory.  We can't assume
    // that the region beyond mmap_end is free because of fixed mappings from
    // the user.
    while (!isUnmapped(start, length)) {
        DPRINTF(Vma, "memstate: cannot extend vma for mmap region at %p. "
                "Virtual address range is already reserved! Skipping a page "
                "and trying again!\n", start);
        start = (_ownerProcess->mmapGrowsDown()) ? start - _pageBytes :
            start + _pageBytes;
    }
 
    DPRINTF(Vma, "memstate: extending mmap region (old %p) (new %p)\n",
            _mmapEnd,
            _ownerProcess->mmapGrowsDown() ? start : start + length);
 
    _mmapEnd = _ownerProcess->mmapGrowsDown() ? start : start + length;
 
    return start;
}
 
std::string
MemState::printVmaList()
{
    std::stringstream file_content;
 
    for (auto vma : _vmaList) {
        std::stringstream line;
        line << std::hex << vma.start() << "-";
        line << std::hex << vma.end() << " ";
        line << "r-xp 00000000 00:00 0 ";
        line << "[" << vma.getName() << "]" << std::endl;
        file_content << line.str();
    }
 
    return file_content.str();
}
 
} // namespace gem5