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/*
* Copyright (c) 2002-2005 The Regents of The University of Michigan
* Copyright (c) 2009 The University of Edinburgh
* 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
* Timothy M. Jones
*/
#ifndef __CPU_TRANSLATION_HH__
#define __CPU_TRANSLATION_HH__
#include "sim/tlb.hh"
/**
* This class captures the state of an address translation. A translation
* can be split in two if the ISA supports it and the memory access crosses
* a page boundary. In this case, this class is shared by two data
* translations (below). Otherwise it is used by a single data translation
* class. When each part of the translation is finished, the finish
* function is called which will indicate whether the whole translation is
* completed or not. There are also functions for accessing parts of the
* translation state which deal with the possible split correctly.
*/
class WholeTranslationState
{
protected:
int outstanding;
Fault faults[2];
public:
bool isSplit;
RequestPtr mainReq;
RequestPtr sreqLow;
RequestPtr sreqHigh;
uint8_t *data;
uint64_t *res;
BaseTLB::Mode mode;
/**
* Single translation state. We set the number of outstanding
* translations to one and indicate that it is not split.
*/
WholeTranslationState(RequestPtr _req, uint8_t *_data, uint64_t *_res,
BaseTLB::Mode _mode)
: outstanding(1), isSplit(false), mainReq(_req), sreqLow(NULL),
sreqHigh(NULL), data(_data), res(_res), mode(_mode)
{
faults[0] = faults[1] = NoFault;
assert(mode == BaseTLB::Read || mode == BaseTLB::Write);
}
/**
* Split translation state. We copy all state into this class, set the
* number of outstanding translations to two and then mark this as a
* split translation.
*/
WholeTranslationState(RequestPtr _req, RequestPtr _sreqLow,
RequestPtr _sreqHigh, uint8_t *_data, uint64_t *_res,
BaseTLB::Mode _mode)
: outstanding(2), isSplit(true), mainReq(_req), sreqLow(_sreqLow),
sreqHigh(_sreqHigh), data(_data), res(_res), mode(_mode)
{
faults[0] = faults[1] = NoFault;
assert(mode == BaseTLB::Read || mode == BaseTLB::Write);
}
/**
* Finish part of a translation. If there is only one request then this
* translation is completed. If the request has been split in two then
* the outstanding count determines whether the translation is complete.
* In this case, flags from the split request are copied to the main
* request to make it easier to access them later on.
*/
bool
finish(Fault fault, int index)
{
assert(outstanding);
faults[index] = fault;
outstanding--;
if (isSplit && outstanding == 0) {
// For ease later, we copy some state to the main request.
if (faults[0] == NoFault) {
mainReq->setPaddr(sreqLow->getPaddr());
}
mainReq->setFlags(sreqLow->getFlags());
mainReq->setFlags(sreqHigh->getFlags());
}
return outstanding == 0;
}
/**
* Determine whether this translation produced a fault. Both parts of the
* translation must be checked if this is a split translation.
*/
Fault
getFault() const
{
if (!isSplit)
return faults[0];
else if (faults[0] != NoFault)
return faults[0];
else if (faults[1] != NoFault)
return faults[1];
else
return NoFault;
}
/** Remove all faults from the translation. */
void
setNoFault()
{
faults[0] = faults[1] = NoFault;
}
/**
* Check if this request is uncacheable. We only need to check the main
* request because the flags will have been copied here on a split
* translation.
*/
bool
isUncacheable() const
{
return mainReq->isUncacheable();
}
/**
* Check if this request is a prefetch. We only need to check the main
* request because the flags will have been copied here on a split
* translation.
*/
bool
isPrefetch() const
{
return mainReq->isPrefetch();
}
/** Get the physical address of this request. */
Addr
getPaddr() const
{
return mainReq->getPaddr();
}
/**
* Get the flags associated with this request. We only need to access
* the main request because the flags will have been copied here on a
* split translation.
*/
unsigned
getFlags()
{
return mainReq->getFlags();
}
/** Delete all requests that make up this translation. */
void
deleteReqs()
{
delete mainReq;
if (isSplit) {
delete sreqLow;
delete sreqHigh;
}
}
};
/**
* This class represents part of a data address translation. All state for
* the translation is held in WholeTranslationState (above). Therefore this
* class does not need to know whether the translation is split or not. The
* index variable determines this but is simply passed on to the state class.
* When this part of the translation is completed, finish is called. If the
* translation state class indicate that the whole translation is complete
* then the execution context is informed.
*/
template <class ExecContext>
class DataTranslation : public BaseTLB::Translation
{
protected:
ExecContext *xc;
WholeTranslationState *state;
int index;
public:
DataTranslation(ExecContext *_xc, WholeTranslationState* _state)
: xc(_xc), state(_state), index(0)
{
}
DataTranslation(ExecContext *_xc, WholeTranslationState* _state,
int _index)
: xc(_xc), state(_state), index(_index)
{
}
/**
* Finish this part of the translation and indicate that the whole
* translation is complete if the state says so.
*/
void
finish(Fault fault, RequestPtr req, ThreadContext *tc,
BaseTLB::Mode mode)
{
assert(state);
assert(mode == state->mode);
if (state->finish(fault, index)) {
xc->finishTranslation(state);
}
delete this;
}
};
#endif // __CPU_TRANSLATION_HH__
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