xref: /gem5/src/arch/mips/process.cc

/*
 * Copyright (c) 2004-2005 The Regents of The University of Michigan
 * All rights reserved.
 *
 * 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: Gabe Black
 *          Ali Saidi
 *          Korey Sewell
 */

#include "arch/mips/isa_traits.hh"
#include "arch/mips/process.hh"
#include "base/loader/object_file.hh"
#include "base/misc.hh"
#include "cpu/thread_context.hh"
#include "sim/system.hh"

using namespace std;
using namespace MipsISA;

static const int SyscallSuccessReg = 7;
static const int FirstArgumentReg = 4;
static const int ReturnValueReg = 2;

MipsLiveProcess::MipsLiveProcess(LiveProcessParams * params,
        ObjectFile *objFile)
    : LiveProcess(params, objFile)
{
    // Set up stack. On MIPS, stack starts at the top of kuseg
    // user address space. MIPS stack grows down from here
    stack_base = 0x7FFFFFFF;

    // Set pointer for next thread stack.  Reserve 8M for main stack.
    next_thread_stack_base = stack_base - (8 * 1024 * 1024);

    // Set up break point (Top of Heap)
    brk_point = objFile->dataBase() + objFile->dataSize() + objFile->bssSize();
    brk_point = roundUp(brk_point, VMPageSize);

    // Set up region for mmaps. For now, start at bottom of kuseg space.
    mmap_start = mmap_end = 0x10000;
}

void
MipsLiveProcess::startup()
{
    argsInit(MachineBytes, VMPageSize);
}

MipsISA::IntReg
MipsLiveProcess::getSyscallArg(ThreadContext *tc, int i)
{
    assert(i < 6);
    return tc->readIntReg(FirstArgumentReg + i);
}

void
MipsLiveProcess::setSyscallArg(ThreadContext *tc,
        int i, MipsISA::IntReg val)
{
    assert(i < 6);
    tc->setIntReg(FirstArgumentReg + i, val);
}

void
MipsLiveProcess::setSyscallReturn(ThreadContext *tc,
        SyscallReturn return_value)
{
    if (return_value.successful()) {
        // no error
        tc->setIntReg(SyscallSuccessReg, 0);
        tc->setIntReg(ReturnValueReg, return_value.value());
    } else {
        // got an error, return details
        tc->setIntReg(SyscallSuccessReg, (IntReg) -1);
        tc->setIntReg(ReturnValueReg, -return_value.value());
    }
}