b904bd5437
Virtualized CPUs and the fastmem mode of the atomic CPU require direct access to physical memory. We currently require caches to be disabled when using them to prevent chaos. This is not ideal when switching between hardware virutalized CPUs and other CPU models as it would require a configuration change on each switch. This changeset introduces a new version of the atomic memory mode, 'atomic_noncaching', where memory accesses are inserted into the memory system as atomic accesses, but bypass caches. To make memory mode tests cleaner, the following methods are added to the System class: * isAtomicMode() -- True if the memory mode is 'atomic' or 'direct'. * isTimingMode() -- True if the memory mode is 'timing'. * bypassCaches() -- True if caches should be bypassed. The old getMemoryMode() and setMemoryMode() methods should never be used from the C++ world anymore.
588 lines
17 KiB
C++
588 lines
17 KiB
C++
/*
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* Copyright (c) 2012 ARM Limited
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* All rights reserved.
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*
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* The license below extends only to copyright in the software and shall
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* not be construed as granting a license to any other intellectual
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* property including but not limited to intellectual property relating
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* to a hardware implementation of the functionality of the software
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* licensed hereunder. You may use the software subject to the license
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* terms below provided that you ensure that this notice is replicated
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* unmodified and in its entirety in all distributions of the software,
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* modified or unmodified, in source code or in binary form.
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*
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* Copyright (c) 2002-2005 The Regents of The University of Michigan
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions are
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* met: redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer;
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* redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution;
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* neither the name of the copyright holders nor the names of its
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* contributors may be used to endorse or promote products derived from
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* this software without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
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* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
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* OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
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* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
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* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*
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* Authors: Steve Reinhardt
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*/
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#include "arch/locked_mem.hh"
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#include "arch/mmapped_ipr.hh"
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#include "arch/utility.hh"
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#include "base/bigint.hh"
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#include "config/the_isa.hh"
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#include "cpu/simple/atomic.hh"
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#include "cpu/exetrace.hh"
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#include "debug/Drain.hh"
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#include "debug/ExecFaulting.hh"
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#include "debug/SimpleCPU.hh"
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#include "mem/packet.hh"
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#include "mem/packet_access.hh"
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#include "mem/physical.hh"
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#include "params/AtomicSimpleCPU.hh"
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#include "sim/faults.hh"
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#include "sim/system.hh"
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#include "sim/full_system.hh"
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using namespace std;
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using namespace TheISA;
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AtomicSimpleCPU::TickEvent::TickEvent(AtomicSimpleCPU *c)
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: Event(CPU_Tick_Pri), cpu(c)
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{
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}
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void
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AtomicSimpleCPU::TickEvent::process()
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{
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cpu->tick();
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}
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const char *
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AtomicSimpleCPU::TickEvent::description() const
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{
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return "AtomicSimpleCPU tick";
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}
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void
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AtomicSimpleCPU::init()
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{
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BaseCPU::init();
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// Initialise the ThreadContext's memory proxies
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tcBase()->initMemProxies(tcBase());
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if (FullSystem && !params()->switched_out) {
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ThreadID size = threadContexts.size();
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for (ThreadID i = 0; i < size; ++i) {
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ThreadContext *tc = threadContexts[i];
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// initialize CPU, including PC
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TheISA::initCPU(tc, tc->contextId());
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}
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}
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// Atomic doesn't do MT right now, so contextId == threadId
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ifetch_req.setThreadContext(_cpuId, 0); // Add thread ID if we add MT
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data_read_req.setThreadContext(_cpuId, 0); // Add thread ID here too
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data_write_req.setThreadContext(_cpuId, 0); // Add thread ID here too
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}
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AtomicSimpleCPU::AtomicSimpleCPU(AtomicSimpleCPUParams *p)
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: BaseSimpleCPU(p), tickEvent(this), width(p->width), locked(false),
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simulate_data_stalls(p->simulate_data_stalls),
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simulate_inst_stalls(p->simulate_inst_stalls),
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drain_manager(NULL),
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icachePort(name() + ".icache_port", this),
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dcachePort(name() + ".dcache_port", this),
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fastmem(p->fastmem)
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{
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_status = Idle;
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}
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AtomicSimpleCPU::~AtomicSimpleCPU()
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{
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if (tickEvent.scheduled()) {
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deschedule(tickEvent);
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}
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}
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unsigned int
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AtomicSimpleCPU::drain(DrainManager *dm)
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{
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assert(!drain_manager);
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if (switchedOut())
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return 0;
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if (!isDrained()) {
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DPRINTF(Drain, "Requesting drain: %s\n", pcState());
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drain_manager = dm;
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return 1;
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} else {
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if (tickEvent.scheduled())
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deschedule(tickEvent);
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DPRINTF(Drain, "Not executing microcode, no need to drain.\n");
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return 0;
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}
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}
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void
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AtomicSimpleCPU::drainResume()
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{
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assert(!tickEvent.scheduled());
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assert(!drain_manager);
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if (switchedOut())
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return;
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DPRINTF(SimpleCPU, "Resume\n");
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verifyMemoryMode();
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assert(!threadContexts.empty());
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if (threadContexts.size() > 1)
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fatal("The atomic CPU only supports one thread.\n");
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if (thread->status() == ThreadContext::Active) {
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schedule(tickEvent, nextCycle());
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_status = BaseSimpleCPU::Running;
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} else {
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_status = BaseSimpleCPU::Idle;
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}
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system->totalNumInsts = 0;
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}
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bool
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AtomicSimpleCPU::tryCompleteDrain()
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{
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if (!drain_manager)
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return false;
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DPRINTF(Drain, "tryCompleteDrain: %s\n", pcState());
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if (!isDrained())
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return false;
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DPRINTF(Drain, "CPU done draining, processing drain event\n");
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drain_manager->signalDrainDone();
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drain_manager = NULL;
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return true;
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}
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void
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AtomicSimpleCPU::switchOut()
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{
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BaseSimpleCPU::switchOut();
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assert(!tickEvent.scheduled());
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assert(_status == BaseSimpleCPU::Running || _status == Idle);
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assert(isDrained());
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}
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void
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AtomicSimpleCPU::takeOverFrom(BaseCPU *oldCPU)
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{
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BaseSimpleCPU::takeOverFrom(oldCPU);
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// The tick event should have been descheduled by drain()
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assert(!tickEvent.scheduled());
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ifetch_req.setThreadContext(_cpuId, 0); // Add thread ID if we add MT
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data_read_req.setThreadContext(_cpuId, 0); // Add thread ID here too
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data_write_req.setThreadContext(_cpuId, 0); // Add thread ID here too
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}
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void
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AtomicSimpleCPU::verifyMemoryMode() const
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{
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if (!system->isAtomicMode()) {
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fatal("The atomic CPU requires the memory system to be in "
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"'atomic' mode.\n");
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}
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}
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void
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AtomicSimpleCPU::activateContext(ThreadID thread_num, Cycles delay)
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{
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DPRINTF(SimpleCPU, "ActivateContext %d (%d cycles)\n", thread_num, delay);
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assert(thread_num == 0);
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assert(thread);
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assert(_status == Idle);
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assert(!tickEvent.scheduled());
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notIdleFraction++;
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numCycles += ticksToCycles(thread->lastActivate - thread->lastSuspend);
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//Make sure ticks are still on multiples of cycles
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schedule(tickEvent, clockEdge(delay));
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_status = BaseSimpleCPU::Running;
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}
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void
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AtomicSimpleCPU::suspendContext(ThreadID thread_num)
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{
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DPRINTF(SimpleCPU, "SuspendContext %d\n", thread_num);
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assert(thread_num == 0);
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assert(thread);
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if (_status == Idle)
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return;
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assert(_status == BaseSimpleCPU::Running);
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// tick event may not be scheduled if this gets called from inside
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// an instruction's execution, e.g. "quiesce"
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if (tickEvent.scheduled())
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deschedule(tickEvent);
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notIdleFraction--;
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_status = Idle;
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}
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Fault
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AtomicSimpleCPU::readMem(Addr addr, uint8_t * data,
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unsigned size, unsigned flags)
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{
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// use the CPU's statically allocated read request and packet objects
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Request *req = &data_read_req;
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if (traceData) {
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traceData->setAddr(addr);
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}
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//The block size of our peer.
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unsigned blockSize = dcachePort.peerBlockSize();
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//The size of the data we're trying to read.
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int fullSize = size;
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//The address of the second part of this access if it needs to be split
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//across a cache line boundary.
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Addr secondAddr = roundDown(addr + size - 1, blockSize);
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if (secondAddr > addr)
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size = secondAddr - addr;
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dcache_latency = 0;
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while (1) {
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req->setVirt(0, addr, size, flags, dataMasterId(), thread->pcState().instAddr());
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// translate to physical address
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Fault fault = thread->dtb->translateAtomic(req, tc, BaseTLB::Read);
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// Now do the access.
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if (fault == NoFault && !req->getFlags().isSet(Request::NO_ACCESS)) {
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Packet pkt = Packet(req,
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req->isLLSC() ? MemCmd::LoadLockedReq :
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MemCmd::ReadReq);
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pkt.dataStatic(data);
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if (req->isMmappedIpr())
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dcache_latency += TheISA::handleIprRead(thread->getTC(), &pkt);
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else {
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if (fastmem && system->isMemAddr(pkt.getAddr()))
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system->getPhysMem().access(&pkt);
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else
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dcache_latency += dcachePort.sendAtomic(&pkt);
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}
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dcache_access = true;
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assert(!pkt.isError());
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if (req->isLLSC()) {
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TheISA::handleLockedRead(thread, req);
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}
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}
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//If there's a fault, return it
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if (fault != NoFault) {
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if (req->isPrefetch()) {
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return NoFault;
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} else {
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return fault;
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}
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}
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//If we don't need to access a second cache line, stop now.
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if (secondAddr <= addr)
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{
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if (req->isLocked() && fault == NoFault) {
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assert(!locked);
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locked = true;
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}
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return fault;
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}
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/*
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* Set up for accessing the second cache line.
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*/
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//Move the pointer we're reading into to the correct location.
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data += size;
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//Adjust the size to get the remaining bytes.
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size = addr + fullSize - secondAddr;
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//And access the right address.
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addr = secondAddr;
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}
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}
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Fault
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AtomicSimpleCPU::writeMem(uint8_t *data, unsigned size,
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Addr addr, unsigned flags, uint64_t *res)
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{
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// use the CPU's statically allocated write request and packet objects
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Request *req = &data_write_req;
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if (traceData) {
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traceData->setAddr(addr);
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}
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//The block size of our peer.
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unsigned blockSize = dcachePort.peerBlockSize();
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//The size of the data we're trying to read.
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int fullSize = size;
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//The address of the second part of this access if it needs to be split
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//across a cache line boundary.
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Addr secondAddr = roundDown(addr + size - 1, blockSize);
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if(secondAddr > addr)
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size = secondAddr - addr;
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dcache_latency = 0;
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while(1) {
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req->setVirt(0, addr, size, flags, dataMasterId(), thread->pcState().instAddr());
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// translate to physical address
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Fault fault = thread->dtb->translateAtomic(req, tc, BaseTLB::Write);
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// Now do the access.
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if (fault == NoFault) {
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MemCmd cmd = MemCmd::WriteReq; // default
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bool do_access = true; // flag to suppress cache access
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if (req->isLLSC()) {
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cmd = MemCmd::StoreCondReq;
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do_access = TheISA::handleLockedWrite(thread, req);
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} else if (req->isSwap()) {
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cmd = MemCmd::SwapReq;
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if (req->isCondSwap()) {
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assert(res);
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req->setExtraData(*res);
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}
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}
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if (do_access && !req->getFlags().isSet(Request::NO_ACCESS)) {
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Packet pkt = Packet(req, cmd);
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pkt.dataStatic(data);
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if (req->isMmappedIpr()) {
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dcache_latency +=
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TheISA::handleIprWrite(thread->getTC(), &pkt);
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} else {
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if (fastmem && system->isMemAddr(pkt.getAddr()))
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system->getPhysMem().access(&pkt);
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else
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dcache_latency += dcachePort.sendAtomic(&pkt);
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}
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dcache_access = true;
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assert(!pkt.isError());
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if (req->isSwap()) {
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assert(res);
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memcpy(res, pkt.getPtr<uint8_t>(), fullSize);
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}
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}
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if (res && !req->isSwap()) {
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*res = req->getExtraData();
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}
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}
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//If there's a fault or we don't need to access a second cache line,
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//stop now.
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if (fault != NoFault || secondAddr <= addr)
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{
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if (req->isLocked() && fault == NoFault) {
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assert(locked);
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locked = false;
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}
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if (fault != NoFault && req->isPrefetch()) {
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return NoFault;
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} else {
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return fault;
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}
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}
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/*
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* Set up for accessing the second cache line.
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*/
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//Move the pointer we're reading into to the correct location.
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data += size;
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//Adjust the size to get the remaining bytes.
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size = addr + fullSize - secondAddr;
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//And access the right address.
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addr = secondAddr;
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}
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}
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void
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AtomicSimpleCPU::tick()
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{
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DPRINTF(SimpleCPU, "Tick\n");
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Tick latency = 0;
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for (int i = 0; i < width || locked; ++i) {
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numCycles++;
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if (!curStaticInst || !curStaticInst->isDelayedCommit())
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checkForInterrupts();
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checkPcEventQueue();
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// We must have just got suspended by a PC event
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if (_status == Idle) {
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tryCompleteDrain();
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return;
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}
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Fault fault = NoFault;
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TheISA::PCState pcState = thread->pcState();
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bool needToFetch = !isRomMicroPC(pcState.microPC()) &&
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!curMacroStaticInst;
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if (needToFetch) {
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setupFetchRequest(&ifetch_req);
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fault = thread->itb->translateAtomic(&ifetch_req, tc,
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BaseTLB::Execute);
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}
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if (fault == NoFault) {
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Tick icache_latency = 0;
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bool icache_access = false;
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dcache_access = false; // assume no dcache access
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if (needToFetch) {
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// This is commented out because the decoder would act like
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// a tiny cache otherwise. It wouldn't be flushed when needed
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// like the I cache. It should be flushed, and when that works
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// this code should be uncommented.
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//Fetch more instruction memory if necessary
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//if(decoder.needMoreBytes())
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//{
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icache_access = true;
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Packet ifetch_pkt = Packet(&ifetch_req, MemCmd::ReadReq);
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ifetch_pkt.dataStatic(&inst);
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if (fastmem && system->isMemAddr(ifetch_pkt.getAddr()))
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system->getPhysMem().access(&ifetch_pkt);
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else
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icache_latency = icachePort.sendAtomic(&ifetch_pkt);
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assert(!ifetch_pkt.isError());
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// ifetch_req is initialized to read the instruction directly
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// into the CPU object's inst field.
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//}
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}
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preExecute();
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if (curStaticInst) {
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fault = curStaticInst->execute(this, traceData);
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// keep an instruction count
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if (fault == NoFault)
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countInst();
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else if (traceData && !DTRACE(ExecFaulting)) {
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delete traceData;
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traceData = NULL;
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}
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postExecute();
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}
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// @todo remove me after debugging with legion done
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if (curStaticInst && (!curStaticInst->isMicroop() ||
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curStaticInst->isFirstMicroop()))
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instCnt++;
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Tick stall_ticks = 0;
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if (simulate_inst_stalls && icache_access)
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stall_ticks += icache_latency;
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if (simulate_data_stalls && dcache_access)
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stall_ticks += dcache_latency;
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if (stall_ticks) {
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// the atomic cpu does its accounting in ticks, so
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// keep counting in ticks but round to the clock
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// period
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latency += divCeil(stall_ticks, clockPeriod()) *
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clockPeriod();
|
|
}
|
|
|
|
}
|
|
if(fault != NoFault || !stayAtPC)
|
|
advancePC(fault);
|
|
}
|
|
|
|
if (tryCompleteDrain())
|
|
return;
|
|
|
|
// instruction takes at least one cycle
|
|
if (latency < clockPeriod())
|
|
latency = clockPeriod();
|
|
|
|
if (_status != Idle)
|
|
schedule(tickEvent, curTick() + latency);
|
|
}
|
|
|
|
|
|
void
|
|
AtomicSimpleCPU::printAddr(Addr a)
|
|
{
|
|
dcachePort.printAddr(a);
|
|
}
|
|
|
|
|
|
////////////////////////////////////////////////////////////////////////
|
|
//
|
|
// AtomicSimpleCPU Simulation Object
|
|
//
|
|
AtomicSimpleCPU *
|
|
AtomicSimpleCPUParams::create()
|
|
{
|
|
numThreads = 1;
|
|
if (!FullSystem && workload.size() != 1)
|
|
panic("only one workload allowed");
|
|
return new AtomicSimpleCPU(this);
|
|
}
|