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/*
* Copyright (c) 2012, 2019 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) 2001-2005 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.
*/
/**
* @file
* AbstractMemory declaration
*/
#ifndef __MEM_ABSTRACT_MEMORY_HH__
#define __MEM_ABSTRACT_MEMORY_HH__
#include "mem/backdoor.hh"
#include "mem/port.hh"
#include "params/AbstractMemory.hh"
#include "sim/clocked_object.hh"
#include "sim/stats.hh"
class System;
/**
* Locked address class that represents a physical address and a
* context id.
*/
class LockedAddr {
private:
// on alpha, minimum LL/SC granularity is 16 bytes, so lower
// bits need to masked off.
static const Addr Addr_Mask = 0xf;
public:
// locked address
Addr addr;
// locking hw context
const ContextID contextId;
static Addr mask(Addr paddr) { return (paddr & ~Addr_Mask); }
// check for matching execution context
bool matchesContext(const RequestPtr &req) const
{
assert(contextId != InvalidContextID);
assert(req->hasContextId());
return (contextId == req->contextId());
}
LockedAddr(const RequestPtr &req) : addr(mask(req->getPaddr())),
contextId(req->contextId())
{}
// constructor for unserialization use
LockedAddr(Addr _addr, int _cid) : addr(_addr), contextId(_cid)
{}
};
/**
* An abstract memory represents a contiguous block of physical
* memory, with an associated address range, and also provides basic
* functionality for reading and writing this memory without any
* timing information. It is a ClockedObject since subclasses may need timing
* information.
*/
class AbstractMemory : public ClockedObject
{
protected:
// Address range of this memory
AddrRange range;
// Pointer to host memory used to implement this memory
uint8_t* pmemAddr;
// Backdoor to access this memory.
MemBackdoor backdoor;
// Enable specific memories to be reported to the configuration table
const bool confTableReported;
// Should the memory appear in the global address map
const bool inAddrMap;
// Should KVM map this memory for the guest
const bool kvmMap;
std::list<LockedAddr> lockedAddrList;
// helper function for checkLockedAddrs(): we really want to
// inline a quick check for an empty locked addr list (hopefully
// the common case), and do the full list search (if necessary) in
// this out-of-line function
bool checkLockedAddrList(PacketPtr pkt);
// Record the address of a load-locked operation so that we can
// clear the execution context's lock flag if a matching store is
// performed
void trackLoadLocked(PacketPtr pkt);
// Compare a store address with any locked addresses so we can
// clear the lock flag appropriately. Return value set to 'false'
// if store operation should be suppressed (because it was a
// conditional store and the address was no longer locked by the
// requesting execution context), 'true' otherwise. Note that
// this method must be called on *all* stores since even
// non-conditional stores must clear any matching lock addresses.
bool writeOK(PacketPtr pkt) {
const RequestPtr &req = pkt->req;
if (lockedAddrList.empty()) {
// no locked addrs: nothing to check, store_conditional fails
bool isLLSC = pkt->isLLSC();
if (isLLSC) {
req->setExtraData(0);
}
return !isLLSC; // only do write if not an sc
} else {
// iterate over list...
return checkLockedAddrList(pkt);
}
}
/** Pointer to the System object.
* This is used for getting the number of requestors in the system which is
* needed when registering stats
*/
System *_system;
struct MemStats : public Stats::Group {
MemStats(AbstractMemory &mem);
void regStats() override;
const AbstractMemory &mem;
/** Number of total bytes read from this memory */
Stats::Vector bytesRead;
/** Number of instruction bytes read from this memory */
Stats::Vector bytesInstRead;
/** Number of bytes written to this memory */
Stats::Vector bytesWritten;
/** Number of read requests */
Stats::Vector numReads;
/** Number of write requests */
Stats::Vector numWrites;
/** Number of other requests */
Stats::Vector numOther;
/** Read bandwidth from this memory */
Stats::Formula bwRead;
/** Read bandwidth from this memory */
Stats::Formula bwInstRead;
/** Write bandwidth from this memory */
Stats::Formula bwWrite;
/** Total bandwidth from this memory */
Stats::Formula bwTotal;
} stats;
private:
// Prevent copying
AbstractMemory(const AbstractMemory&);
// Prevent assignment
AbstractMemory& operator=(const AbstractMemory&);
public:
typedef AbstractMemoryParams Params;
AbstractMemory(const Params* p);
virtual ~AbstractMemory() {}
void initState() override;
/**
* See if this is a null memory that should never store data and
* always return zero.
*
* @return true if null
*/
bool isNull() const { return params()->null; }
/**
* Set the host memory backing store to be used by this memory
* controller.
*
* @param pmem_addr Pointer to a segment of host memory
*/
void setBackingStore(uint8_t* pmem_addr);
/**
* Get the list of locked addresses to allow checkpointing.
*/
const std::list<LockedAddr>& getLockedAddrList() const
{ return lockedAddrList; }
/**
* Add a locked address to allow for checkpointing.
*/
void addLockedAddr(LockedAddr addr) { lockedAddrList.push_back(addr); }
/** read the system pointer
* Implemented for completeness with the setter
* @return pointer to the system object */
System* system() const { return _system; }
/** Set the system pointer on this memory
* This can't be done via a python parameter because the system needs
* pointers to all the memories and the reverse would create a cycle in the
* object graph. An init() this is set.
* @param sys system pointer to set
*/
void system(System *sys) { _system = sys; }
const Params *
params() const
{
return dynamic_cast<const Params *>(_params);
}
/**
* Get the address range
*
* @return a single contigous address range
*/
AddrRange getAddrRange() const;
/**
* Transform a gem5 address space address into its physical counterpart
* in the host address space.
*
* @param addr Address in gem5's address space.
* @return Pointer to the corresponding memory address of the host.
*/
inline uint8_t *
toHostAddr(Addr addr) const
{
return pmemAddr + addr - range.start();
}
/**
* Get the memory size.
*
* @return the size of the memory
*/
uint64_t size() const { return range.size(); }
/**
* Get the start address.
*
* @return the start address of the memory
*/
Addr start() const { return range.start(); }
/**
* Should this memory be passed to the kernel and part of the OS
* physical memory layout.
*
* @return if this memory is reported
*/
bool isConfReported() const { return confTableReported; }
/**
* Some memories are used as shadow memories or should for other
* reasons not be part of the global address map.
*
* @return if this memory is part of the address map
*/
bool isInAddrMap() const { return inAddrMap; }
/**
* When shadow memories are in use, KVM may want to make one or the other,
* but cannot map both into the guest address space.
*
* @return if this memory should be mapped into the KVM guest address space
*/
bool isKvmMap() const { return kvmMap; }
/**
* Perform an untimed memory access and update all the state
* (e.g. locked addresses) and statistics accordingly. The packet
* is turned into a response if required.
*
* @param pkt Packet performing the access
*/
void access(PacketPtr pkt);
/**
* Perform an untimed memory read or write without changing
* anything but the memory itself. No stats are affected by this
* access. In addition to normal accesses this also facilitates
* print requests.
*
* @param pkt Packet performing the access
*/
void functionalAccess(PacketPtr pkt);
};
#endif //__MEM_ABSTRACT_MEMORY_HH__