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/*
* Copyright (c) 2012-2013,2015 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.
*
* Copyright (c) 2002-2005 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: Steve Reinhardt
*/
#ifndef __CPU_SIMPLE_ATOMIC_HH__
#define __CPU_SIMPLE_ATOMIC_HH__
#include "cpu/simple/base.hh"
#include "cpu/simple/exec_context.hh"
#include "mem/request.hh"
#include "params/AtomicSimpleCPU.hh"
#include "sim/probe/probe.hh"
class AtomicSimpleCPU : public BaseSimpleCPU
{
public:
AtomicSimpleCPU(AtomicSimpleCPUParams *params);
virtual ~AtomicSimpleCPU();
void init() override;
private:
EventFunctionWrapper tickEvent;
const int width;
bool locked;
const bool simulate_data_stalls;
const bool simulate_inst_stalls;
// main simulation loop (one cycle)
void tick();
/**
* Check if a system is in a drained state.
*
* We need to drain if:
* <ul>
* <li>We are in the middle of a microcode sequence as some CPUs
* (e.g., HW accelerated CPUs) can't be started in the middle
* of a gem5 microcode sequence.
*
* <li>The CPU is in a LLSC region. This shouldn't normally happen
* as these are executed atomically within a single tick()
* call. The only way this can happen at the moment is if
* there is an event in the PC event queue that affects the
* CPU state while it is in an LLSC region.
*
* <li>Stay at PC is true.
* </ul>
*/
bool isDrained() {
SimpleExecContext &t_info = *threadInfo[curThread];
return t_info.thread->microPC() == 0 &&
!locked &&
!t_info.stayAtPC;
}
/**
* Try to complete a drain request.
*
* @returns true if the CPU is drained, false otherwise.
*/
bool tryCompleteDrain();
/**
* An AtomicCPUPort overrides the default behaviour of the
* recvAtomicSnoop and ignores the packet instead of panicking. It
* also provides an implementation for the purely virtual timing
* functions and panics on either of these.
*/
class AtomicCPUPort : public MasterPort
{
public:
AtomicCPUPort(const std::string &_name, BaseSimpleCPU* _cpu)
: MasterPort(_name, _cpu)
{ }
protected:
bool recvTimingResp(PacketPtr pkt)
{
panic("Atomic CPU doesn't expect recvTimingResp!\n");
return true;
}
void recvReqRetry()
{
panic("Atomic CPU doesn't expect recvRetry!\n");
}
};
class AtomicCPUDPort : public AtomicCPUPort
{
public:
AtomicCPUDPort(const std::string &_name, BaseSimpleCPU* _cpu)
: AtomicCPUPort(_name, _cpu), cpu(_cpu)
{
cacheBlockMask = ~(cpu->cacheLineSize() - 1);
}
bool isSnooping() const { return true; }
Addr cacheBlockMask;
protected:
BaseSimpleCPU *cpu;
virtual Tick recvAtomicSnoop(PacketPtr pkt);
virtual void recvFunctionalSnoop(PacketPtr pkt);
};
AtomicCPUPort icachePort;
AtomicCPUDPort dcachePort;
bool fastmem;
RequestPtr ifetch_req;
RequestPtr data_read_req;
RequestPtr data_write_req;
bool dcache_access;
Tick dcache_latency;
/** Probe Points. */
ProbePointArg<std::pair<SimpleThread*, const StaticInstPtr>> *ppCommit;
protected:
/** Return a reference to the data port. */
MasterPort &getDataPort() override { return dcachePort; }
/** Return a reference to the instruction port. */
MasterPort &getInstPort() override { return icachePort; }
/** Perform snoop for other cpu-local thread contexts. */
void threadSnoop(PacketPtr pkt, ThreadID sender);
public:
DrainState drain() override;
void drainResume() override;
void switchOut() override;
void takeOverFrom(BaseCPU *oldCPU) override;
void verifyMemoryMode() const override;
void activateContext(ThreadID thread_num) override;
void suspendContext(ThreadID thread_num) override;
Fault readMem(Addr addr, uint8_t *data, unsigned size,
Request::Flags flags) override;
Fault initiateMemRead(Addr addr, unsigned size,
Request::Flags flags) override;
Fault writeMem(uint8_t *data, unsigned size,
Addr addr, Request::Flags flags, uint64_t *res) override;
void regProbePoints() override;
/**
* Print state of address in memory system via PrintReq (for
* debugging).
*/
void printAddr(Addr a);
};
#endif // __CPU_SIMPLE_ATOMIC_HH__
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