src/mem/cache/cache.hh - public/gem5 - Git at Google

 /*
  * 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: Erik Hallnor
  *          Dave Greene
  *          Steve Reinhardt
  *          Ron Dreslinski
  */

 /**
  * @file
  * Describes a cache based on template policies.
  */

 #ifndef __CACHE_HH__
 #define __CACHE_HH__

 #include "base/misc.hh" // fatal, panic, and warn

 #include "mem/cache/base.hh"
 #include "mem/cache/blk.hh"
 #include "mem/cache/mshr.hh"

 #include "sim/eventq.hh"

 //Forward decleration
 class BasePrefetcher;

 /**
  * A template-policy based cache. The behavior of the cache can be altered by
  * supplying different template policies. TagStore handles all tag and data
  * storage @sa TagStore.
  */
 template <class TagStore>
 class Cache : public BaseCache
 {
   public:
     /** Define the type of cache block to use. */
     typedef typename TagStore::BlkType BlkType;
     /** A typedef for a list of BlkType pointers. */
     typedef typename TagStore::BlkList BlkList;

     bool prefetchAccess;

   protected:

     class CpuSidePort : public CachePort
     {
       public:
         CpuSidePort(const std::string &_name,
                     Cache<TagStore> *_cache,
                     const std::string &_label,
                     std::vector<Range<Addr> > filterRanges);

         // BaseCache::CachePort just has a BaseCache *; this function
         // lets us get back the type info we lost when we stored the
         // cache pointer there.
         Cache<TagStore> *myCache() {
             return static_cast<Cache<TagStore> *>(cache);
         }

         virtual void getDeviceAddressRanges(AddrRangeList &resp,
                                             bool &snoop);

         virtual bool recvTiming(PacketPtr pkt);

         virtual Tick recvAtomic(PacketPtr pkt);

         virtual void recvFunctional(PacketPtr pkt);
     };

     class MemSidePort : public CachePort
     {
       public:
         MemSidePort(const std::string &_name,
                     Cache<TagStore> *_cache,
                     const std::string &_label,
                     std::vector<Range<Addr> > filterRanges);

         // BaseCache::CachePort just has a BaseCache *; this function
         // lets us get back the type info we lost when we stored the
         // cache pointer there.
         Cache<TagStore> *myCache() {
             return static_cast<Cache<TagStore> *>(cache);
         }

         void sendPacket();

         void processSendEvent();

         virtual void getDeviceAddressRanges(AddrRangeList &resp,
                                             bool &snoop);

         virtual bool recvTiming(PacketPtr pkt);

         virtual void recvRetry();

         virtual Tick recvAtomic(PacketPtr pkt);

         virtual void recvFunctional(PacketPtr pkt);

         typedef EventWrapper<MemSidePort, &MemSidePort::processSendEvent>
                 SendEvent;
     };

     /** Tag and data Storage */
     TagStore *tags;

     /** Prefetcher */
     BasePrefetcher *prefetcher;

     /** Temporary cache block for occasional transitory use */
     BlkType *tempBlock;

     /**
      * Can this cache should allocate a block on a line-sized write miss.
      */
     const bool doFastWrites;

     const bool prefetchMiss;

     /**
      * Handle a replacement for the given request.
      * @param blk A pointer to the block, usually NULL
      * @param pkt The memory request to satisfy.
      * @param new_state The new state of the block.
      * @param writebacks A list to store any generated writebacks.
      */
     BlkType* doReplacement(BlkType *blk, PacketPtr pkt,
                            CacheBlk::State new_state, PacketList &writebacks);

     /**
      * Does all the processing necessary to perform the provided request.
      * @param pkt The memory request to perform.
      * @param lat The latency of the access.
      * @param writebacks List for any writebacks that need to be performed.
      * @param update True if the replacement data should be updated.
      * @return Pointer to the cache block touched by the request. NULL if it
      * was a miss.
      */
     bool access(PacketPtr pkt, BlkType *&blk,
                 int &lat, PacketList &writebacks);

     /**
      *Handle doing the Compare and Swap function for SPARC.
      */
     void cmpAndSwap(BlkType *blk, PacketPtr pkt);

     /**
      * Find a block frame for new block at address addr, assuming that
      * the block is not currently in the cache.  Append writebacks if
      * any to provided packet list.  Return free block frame.  May
      * return NULL if there are no replaceable blocks at the moment.
      */
     BlkType *allocateBlock(Addr addr, PacketList &writebacks);

     /**
      * Populates a cache block and handles all outstanding requests for the
      * satisfied fill request. This version takes two memory requests. One
      * contains the fill data, the other is an optional target to satisfy.
      * Used for Cache::probe.
      * @param pkt The memory request with the fill data.
      * @param blk The cache block if it already exists.
      * @param writebacks List for any writebacks that need to be performed.
      * @return Pointer to the new cache block.
      */
     BlkType *handleFill(PacketPtr pkt, BlkType *blk,
                         PacketList &writebacks);

     void satisfyCpuSideRequest(PacketPtr pkt, BlkType *blk);
     bool satisfyMSHR(MSHR *mshr, PacketPtr pkt, BlkType *blk);

     void doTimingSupplyResponse(PacketPtr req_pkt, uint8_t *blk_data,
                                 bool already_copied, bool pending_inval);

     /**
      * Sets the blk to the new state.
      * @param blk The cache block being snooped.
      * @param new_state The new coherence state for the block.
      */
     void handleSnoop(PacketPtr ptk, BlkType *blk,
                      bool is_timing, bool is_deferred, bool pending_inval);

     /**
      * Create a writeback request for the given block.
      * @param blk The block to writeback.
      * @return The writeback request for the block.
      */
     PacketPtr writebackBlk(BlkType *blk);

   public:
     /** Instantiates a basic cache object. */
     Cache(const Params *p, TagStore *tags, BasePrefetcher *prefetcher);

     virtual Port *getPort(const std::string &if_name, int idx = -1);
     virtual void deletePortRefs(Port *p);

     void regStats();

     /**
      * Performs the access specified by the request.
      * @param pkt The request to perform.
      * @return The result of the access.
      */
     bool timingAccess(PacketPtr pkt);

     /**
      * Performs the access specified by the request.
      * @param pkt The request to perform.
      * @return The result of the access.
      */
     Tick atomicAccess(PacketPtr pkt);

     /**
      * Performs the access specified by the request.
      * @param pkt The request to perform.
      * @return The result of the access.
      */
     void functionalAccess(PacketPtr pkt, CachePort *incomingPort,
                           CachePort *otherSidePort);

     /**
      * Handles a response (cache line fill/write ack) from the bus.
      * @param pkt The request being responded to.
      */
     void handleResponse(PacketPtr pkt);

     /**
      * Snoops bus transactions to maintain coherence.
      * @param pkt The current bus transaction.
      */
     void snoopTiming(PacketPtr pkt);

     /**
      * Snoop for the provided request in the cache and return the estimated
      * time of completion.
      * @param pkt The memory request to snoop
      * @return The estimated completion time.
      */
     Tick snoopAtomic(PacketPtr pkt);

     /**
      * Squash all requests associated with specified thread.
      * intended for use by I-cache.
      * @param threadNum The thread to squash.
      */
     void squash(int threadNum);

     /**
      * Generate an appropriate downstream bus request packet for the
      * given parameters.
      * @param cpu_pkt  The upstream request that needs to be satisfied.
      * @param blk The block currently in the cache corresponding to
      * cpu_pkt (NULL if none).
      * @param needsExclusive  Indicates that an exclusive copy is required
      * even if the request in cpu_pkt doesn't indicate that.
      * @return A new Packet containing the request, or NULL if the
      * current request in cpu_pkt should just be forwarded on.
      */
     PacketPtr getBusPacket(PacketPtr cpu_pkt, BlkType *blk,
                            bool needsExclusive);

     /**
      * Return the next MSHR to service, either a pending miss from the
      * mshrQueue, a buffered write from the write buffer, or something
      * from the prefetcher.  This function is responsible for
      * prioritizing among those sources on the fly.
      */
     MSHR *getNextMSHR();

     /**
      * Selects an outstanding request to service.  Called when the
      * cache gets granted the downstream bus in timing mode.
      * @return The request to service, NULL if none found.
      */
     PacketPtr getTimingPacket();

     /**
      * Marks a request as in service (sent on the bus). This can have side
      * effect since storage for no response commands is deallocated once they
      * are successfully sent.
      * @param pkt The request that was sent on the bus.
      */
     void markInService(MSHR *mshr);

     /**
      * Perform the given writeback request.
      * @param pkt The writeback request.
      */
     void doWriteback(PacketPtr pkt);

     /**
      * Return whether there are any outstanding misses.
      */
     bool outstandingMisses() const
     {
         return mshrQueue.allocated != 0;
     }

     CacheBlk *findBlock(Addr addr) {
         return tags->findBlock(addr);
     }

     bool inCache(Addr addr) {
         return (tags->findBlock(addr) != 0);
     }

     bool inMissQueue(Addr addr) {
         return (mshrQueue.findMatch(addr) != 0);
     }
 };

 #endif // __CACHE_HH__
	/*
	* 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: Erik Hallnor
	* Dave Greene
	* Steve Reinhardt
	* Ron Dreslinski
	*/

	/**
	* @file
	* Describes a cache based on template policies.
	*/

	#ifndef __CACHE_HH__
	#define __CACHE_HH__

	#include "base/misc.hh" // fatal, panic, and warn

	#include "mem/cache/base.hh"
	#include "mem/cache/blk.hh"
	#include "mem/cache/mshr.hh"

	#include "sim/eventq.hh"

	//Forward decleration
	class BasePrefetcher;

	/**
	* A template-policy based cache. The behavior of the cache can be altered by
	* supplying different template policies. TagStore handles all tag and data
	* storage @sa TagStore.
	*/
	template <class TagStore>
	class Cache : public BaseCache
	{
	public:
	/** Define the type of cache block to use. */
	typedef typename TagStore::BlkType BlkType;
	/** A typedef for a list of BlkType pointers. */
	typedef typename TagStore::BlkList BlkList;

	bool prefetchAccess;

	protected:

	class CpuSidePort : public CachePort
	{
	public:
	CpuSidePort(const std::string &_name,
	Cache<TagStore> *_cache,
	const std::string &_label,
	std::vector<Range<Addr> > filterRanges);

	// BaseCache::CachePort just has a BaseCache *; this function
	// lets us get back the type info we lost when we stored the
	// cache pointer there.
	Cache<TagStore> *myCache() {
	return static_cast<Cache<TagStore> *>(cache);
	}

	virtual void getDeviceAddressRanges(AddrRangeList &resp,
	bool &snoop);

	virtual bool recvTiming(PacketPtr pkt);

	virtual Tick recvAtomic(PacketPtr pkt);

	virtual void recvFunctional(PacketPtr pkt);
	};

	class MemSidePort : public CachePort
	{
	public:
	MemSidePort(const std::string &_name,
	Cache<TagStore> *_cache,
	const std::string &_label,
	std::vector<Range<Addr> > filterRanges);

	// BaseCache::CachePort just has a BaseCache *; this function
	// lets us get back the type info we lost when we stored the
	// cache pointer there.
	Cache<TagStore> *myCache() {
	return static_cast<Cache<TagStore> *>(cache);
	}

	void sendPacket();

	void processSendEvent();

	virtual void getDeviceAddressRanges(AddrRangeList &resp,
	bool &snoop);

	virtual bool recvTiming(PacketPtr pkt);

	virtual void recvRetry();

	virtual Tick recvAtomic(PacketPtr pkt);

	virtual void recvFunctional(PacketPtr pkt);

	typedef EventWrapper<MemSidePort, &MemSidePort::processSendEvent>
	SendEvent;
	};

	/** Tag and data Storage */
	TagStore *tags;

	/** Prefetcher */
	BasePrefetcher *prefetcher;

	/** Temporary cache block for occasional transitory use */
	BlkType *tempBlock;

	/**
	* Can this cache should allocate a block on a line-sized write miss.
	*/
	const bool doFastWrites;

	const bool prefetchMiss;

	/**
	* Handle a replacement for the given request.
	* @param blk A pointer to the block, usually NULL
	* @param pkt The memory request to satisfy.
	* @param new_state The new state of the block.
	* @param writebacks A list to store any generated writebacks.
	*/
	BlkType* doReplacement(BlkType *blk, PacketPtr pkt,
	CacheBlk::State new_state, PacketList &writebacks);

	/**
	* Does all the processing necessary to perform the provided request.
	* @param pkt The memory request to perform.
	* @param lat The latency of the access.
	* @param writebacks List for any writebacks that need to be performed.
	* @param update True if the replacement data should be updated.
	* @return Pointer to the cache block touched by the request. NULL if it
	* was a miss.
	*/
	bool access(PacketPtr pkt, BlkType *&blk,
	int &lat, PacketList &writebacks);

	/**
	*Handle doing the Compare and Swap function for SPARC.
	*/
	void cmpAndSwap(BlkType *blk, PacketPtr pkt);

	/**
	* Find a block frame for new block at address addr, assuming that
	* the block is not currently in the cache. Append writebacks if
	* any to provided packet list. Return free block frame. May
	* return NULL if there are no replaceable blocks at the moment.
	*/
	BlkType *allocateBlock(Addr addr, PacketList &writebacks);

	/**
	* Populates a cache block and handles all outstanding requests for the
	* satisfied fill request. This version takes two memory requests. One
	* contains the fill data, the other is an optional target to satisfy.
	* Used for Cache::probe.
	* @param pkt The memory request with the fill data.
	* @param blk The cache block if it already exists.
	* @param writebacks List for any writebacks that need to be performed.
	* @return Pointer to the new cache block.
	*/
	BlkType handleFill(PacketPtr pkt, BlkType blk,
	PacketList &writebacks);

	void satisfyCpuSideRequest(PacketPtr pkt, BlkType *blk);
	bool satisfyMSHR(MSHR mshr, PacketPtr pkt, BlkType blk);

	void doTimingSupplyResponse(PacketPtr req_pkt, uint8_t *blk_data,
	bool already_copied, bool pending_inval);

	/**
	* Sets the blk to the new state.
	* @param blk The cache block being snooped.
	* @param new_state The new coherence state for the block.
	*/
	void handleSnoop(PacketPtr ptk, BlkType *blk,
	bool is_timing, bool is_deferred, bool pending_inval);

	/**
	* Create a writeback request for the given block.
	* @param blk The block to writeback.
	* @return The writeback request for the block.
	*/
	PacketPtr writebackBlk(BlkType *blk);

	public:
	/** Instantiates a basic cache object. */
	Cache(const Params p, TagStore tags, BasePrefetcher *prefetcher);

	virtual Port *getPort(const std::string &if_name, int idx = -1);
	virtual void deletePortRefs(Port *p);

	void regStats();

	/**
	* Performs the access specified by the request.
	* @param pkt The request to perform.
	* @return The result of the access.
	*/
	bool timingAccess(PacketPtr pkt);

	/**
	* Performs the access specified by the request.
	* @param pkt The request to perform.
	* @return The result of the access.
	*/
	Tick atomicAccess(PacketPtr pkt);

	/**
	* Performs the access specified by the request.
	* @param pkt The request to perform.
	* @return The result of the access.
	*/
	void functionalAccess(PacketPtr pkt, CachePort *incomingPort,
	CachePort *otherSidePort);

	/**
	* Handles a response (cache line fill/write ack) from the bus.
	* @param pkt The request being responded to.
	*/
	void handleResponse(PacketPtr pkt);

	/**
	* Snoops bus transactions to maintain coherence.
	* @param pkt The current bus transaction.
	*/
	void snoopTiming(PacketPtr pkt);

	/**
	* Snoop for the provided request in the cache and return the estimated
	* time of completion.
	* @param pkt The memory request to snoop
	* @return The estimated completion time.
	*/
	Tick snoopAtomic(PacketPtr pkt);

	/**
	* Squash all requests associated with specified thread.
	* intended for use by I-cache.
	* @param threadNum The thread to squash.
	*/
	void squash(int threadNum);

	/**
	* Generate an appropriate downstream bus request packet for the
	* given parameters.
	* @param cpu_pkt The upstream request that needs to be satisfied.
	* @param blk The block currently in the cache corresponding to
	* cpu_pkt (NULL if none).
	* @param needsExclusive Indicates that an exclusive copy is required
	* even if the request in cpu_pkt doesn't indicate that.
	* @return A new Packet containing the request, or NULL if the
	* current request in cpu_pkt should just be forwarded on.
	*/
	PacketPtr getBusPacket(PacketPtr cpu_pkt, BlkType *blk,
	bool needsExclusive);

	/**
	* Return the next MSHR to service, either a pending miss from the
	* mshrQueue, a buffered write from the write buffer, or something
	* from the prefetcher. This function is responsible for
	* prioritizing among those sources on the fly.
	*/
	MSHR *getNextMSHR();

	/**
	* Selects an outstanding request to service. Called when the
	* cache gets granted the downstream bus in timing mode.
	* @return The request to service, NULL if none found.
	*/
	PacketPtr getTimingPacket();

	/**
	* Marks a request as in service (sent on the bus). This can have side
	* effect since storage for no response commands is deallocated once they
	* are successfully sent.
	* @param pkt The request that was sent on the bus.
	*/
	void markInService(MSHR *mshr);

	/**
	* Perform the given writeback request.
	* @param pkt The writeback request.
	*/
	void doWriteback(PacketPtr pkt);

	/**
	* Return whether there are any outstanding misses.
	*/
	bool outstandingMisses() const
	{
	return mshrQueue.allocated != 0;
	}

	CacheBlk *findBlock(Addr addr) {
	return tags->findBlock(addr);
	}

	bool inCache(Addr addr) {
	return (tags->findBlock(addr) != 0);
	}

	bool inMissQueue(Addr addr) {
	return (mshrQueue.findMatch(addr) != 0);
	}
	};

	#endif // __CACHE_HH__