cache.hh revision 5494
1/* 2 * Copyright (c) 2002-2005 The Regents of The University of Michigan 3 * All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions are 7 * met: redistributions of source code must retain the above copyright 8 * notice, this list of conditions and the following disclaimer; 9 * redistributions in binary form must reproduce the above copyright 10 * notice, this list of conditions and the following disclaimer in the 11 * documentation and/or other materials provided with the distribution; 12 * neither the name of the copyright holders nor the names of its 13 * contributors may be used to endorse or promote products derived from 14 * this software without specific prior written permission. 15 * 16 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 17 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 18 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR 19 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT 20 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 21 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT 22 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 23 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 24 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 25 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE 26 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 27 * 28 * Authors: Erik Hallnor 29 * Dave Greene 30 * Steve Reinhardt 31 * Ron Dreslinski 32 */ 33 34/** 35 * @file 36 * Describes a cache based on template policies. 37 */ 38 39#ifndef __CACHE_HH__ 40#define __CACHE_HH__ 41 42#include "base/misc.hh" // fatal, panic, and warn 43 44#include "mem/cache/base.hh" 45#include "mem/cache/blk.hh" 46#include "mem/cache/mshr.hh" 47 48#include "sim/eventq.hh" 49 50//Forward decleration 51class BasePrefetcher; 52 53/** 54 * A template-policy based cache. The behavior of the cache can be altered by 55 * supplying different template policies. TagStore handles all tag and data 56 * storage @sa TagStore. 57 */ 58template <class TagStore> 59class Cache : public BaseCache 60{ 61 public: 62 /** Define the type of cache block to use. */ 63 typedef typename TagStore::BlkType BlkType; 64 /** A typedef for a list of BlkType pointers. */ 65 typedef typename TagStore::BlkList BlkList; 66 67 bool prefetchAccess; 68 69 protected: 70 71 class CpuSidePort : public CachePort 72 { 73 public: 74 CpuSidePort(const std::string &_name, 75 Cache<TagStore> *_cache, 76 const std::string &_label, 77 std::vector<Range<Addr> > filterRanges); 78 79 // BaseCache::CachePort just has a BaseCache *; this function 80 // lets us get back the type info we lost when we stored the 81 // cache pointer there. 82 Cache<TagStore> *myCache() { 83 return static_cast<Cache<TagStore> *>(cache); 84 } 85 86 virtual void getDeviceAddressRanges(AddrRangeList &resp, 87 bool &snoop); 88 89 virtual bool recvTiming(PacketPtr pkt); 90 91 virtual Tick recvAtomic(PacketPtr pkt); 92 93 virtual void recvFunctional(PacketPtr pkt); 94 }; 95 96 class MemSidePort : public CachePort 97 { 98 public: 99 MemSidePort(const std::string &_name, 100 Cache<TagStore> *_cache, 101 const std::string &_label, 102 std::vector<Range<Addr> > filterRanges); 103 104 // BaseCache::CachePort just has a BaseCache *; this function 105 // lets us get back the type info we lost when we stored the 106 // cache pointer there. 107 Cache<TagStore> *myCache() { 108 return static_cast<Cache<TagStore> *>(cache); 109 } 110 111 void sendPacket(); 112 113 void processSendEvent(); 114 115 virtual void getDeviceAddressRanges(AddrRangeList &resp, 116 bool &snoop); 117 118 virtual bool recvTiming(PacketPtr pkt); 119 120 virtual void recvRetry(); 121 122 virtual Tick recvAtomic(PacketPtr pkt); 123 124 virtual void recvFunctional(PacketPtr pkt); 125 126 typedef EventWrapper<MemSidePort, &MemSidePort::processSendEvent> 127 SendEvent; 128 }; 129 130 /** Tag and data Storage */ 131 TagStore *tags; 132 133 /** Prefetcher */ 134 BasePrefetcher *prefetcher; 135 136 /** Temporary cache block for occasional transitory use */ 137 BlkType *tempBlock; 138 139 /** 140 * Can this cache should allocate a block on a line-sized write miss. 141 */ 142 const bool doFastWrites; 143 144 const bool prefetchMiss; 145 146 /** 147 * Handle a replacement for the given request. 148 * @param blk A pointer to the block, usually NULL 149 * @param pkt The memory request to satisfy. 150 * @param new_state The new state of the block. 151 * @param writebacks A list to store any generated writebacks. 152 */ 153 BlkType* doReplacement(BlkType *blk, PacketPtr pkt, 154 CacheBlk::State new_state, PacketList &writebacks); 155 156 /** 157 * Does all the processing necessary to perform the provided request. 158 * @param pkt The memory request to perform. 159 * @param lat The latency of the access. 160 * @param writebacks List for any writebacks that need to be performed. 161 * @param update True if the replacement data should be updated. 162 * @return Pointer to the cache block touched by the request. NULL if it 163 * was a miss. 164 */ 165 bool access(PacketPtr pkt, BlkType *&blk, 166 int &lat, PacketList &writebacks); 167 168 /** 169 *Handle doing the Compare and Swap function for SPARC. 170 */ 171 void cmpAndSwap(BlkType *blk, PacketPtr pkt); 172 173 /** 174 * Find a block frame for new block at address addr, assuming that 175 * the block is not currently in the cache. Append writebacks if 176 * any to provided packet list. Return free block frame. May 177 * return NULL if there are no replaceable blocks at the moment. 178 */ 179 BlkType *allocateBlock(Addr addr, PacketList &writebacks); 180 181 /** 182 * Populates a cache block and handles all outstanding requests for the 183 * satisfied fill request. This version takes two memory requests. One 184 * contains the fill data, the other is an optional target to satisfy. 185 * Used for Cache::probe. 186 * @param pkt The memory request with the fill data. 187 * @param blk The cache block if it already exists. 188 * @param writebacks List for any writebacks that need to be performed. 189 * @return Pointer to the new cache block. 190 */ 191 BlkType *handleFill(PacketPtr pkt, BlkType *blk, 192 PacketList &writebacks); 193 194 void satisfyCpuSideRequest(PacketPtr pkt, BlkType *blk); 195 bool satisfyMSHR(MSHR *mshr, PacketPtr pkt, BlkType *blk); 196 197 void doTimingSupplyResponse(PacketPtr req_pkt, uint8_t *blk_data, 198 bool already_copied, bool pending_inval); 199 200 /** 201 * Sets the blk to the new state. 202 * @param blk The cache block being snooped. 203 * @param new_state The new coherence state for the block. 204 */ 205 void handleSnoop(PacketPtr ptk, BlkType *blk, 206 bool is_timing, bool is_deferred, bool pending_inval); 207 208 /** 209 * Create a writeback request for the given block. 210 * @param blk The block to writeback. 211 * @return The writeback request for the block. 212 */ 213 PacketPtr writebackBlk(BlkType *blk); 214 215 public: 216 /** Instantiates a basic cache object. */ 217 Cache(const Params *p, TagStore *tags, BasePrefetcher *prefetcher); 218 219 virtual Port *getPort(const std::string &if_name, int idx = -1); 220 virtual void deletePortRefs(Port *p); 221 222 void regStats(); 223 224 /** 225 * Performs the access specified by the request. 226 * @param pkt The request to perform. 227 * @return The result of the access. 228 */ 229 bool timingAccess(PacketPtr pkt); 230 231 /** 232 * Performs the access specified by the request. 233 * @param pkt The request to perform. 234 * @return The result of the access. 235 */ 236 Tick atomicAccess(PacketPtr pkt); 237 238 /** 239 * Performs the access specified by the request. 240 * @param pkt The request to perform. 241 * @return The result of the access. 242 */ 243 void functionalAccess(PacketPtr pkt, CachePort *incomingPort, 244 CachePort *otherSidePort); 245 246 /** 247 * Handles a response (cache line fill/write ack) from the bus. 248 * @param pkt The request being responded to. 249 */ 250 void handleResponse(PacketPtr pkt); 251 252 /** 253 * Snoops bus transactions to maintain coherence. 254 * @param pkt The current bus transaction. 255 */ 256 void snoopTiming(PacketPtr pkt); 257 258 /** 259 * Snoop for the provided request in the cache and return the estimated 260 * time of completion. 261 * @param pkt The memory request to snoop 262 * @return The estimated completion time. 263 */ 264 Tick snoopAtomic(PacketPtr pkt); 265 266 /** 267 * Squash all requests associated with specified thread. 268 * intended for use by I-cache. 269 * @param threadNum The thread to squash. 270 */ 271 void squash(int threadNum); 272 273 /** 274 * Generate an appropriate downstream bus request packet for the 275 * given parameters. 276 * @param cpu_pkt The upstream request that needs to be satisfied. 277 * @param blk The block currently in the cache corresponding to 278 * cpu_pkt (NULL if none). 279 * @param needsExclusive Indicates that an exclusive copy is required 280 * even if the request in cpu_pkt doesn't indicate that. 281 * @return A new Packet containing the request, or NULL if the 282 * current request in cpu_pkt should just be forwarded on. 283 */ 284 PacketPtr getBusPacket(PacketPtr cpu_pkt, BlkType *blk, 285 bool needsExclusive); 286 287 /** 288 * Return the next MSHR to service, either a pending miss from the 289 * mshrQueue, a buffered write from the write buffer, or something 290 * from the prefetcher. This function is responsible for 291 * prioritizing among those sources on the fly. 292 */ 293 MSHR *getNextMSHR(); 294 295 /** 296 * Selects an outstanding request to service. Called when the 297 * cache gets granted the downstream bus in timing mode. 298 * @return The request to service, NULL if none found. 299 */ 300 PacketPtr getTimingPacket(); 301 302 /** 303 * Marks a request as in service (sent on the bus). This can have side 304 * effect since storage for no response commands is deallocated once they 305 * are successfully sent. 306 * @param pkt The request that was sent on the bus. 307 */ 308 void markInService(MSHR *mshr); 309 310 /** 311 * Perform the given writeback request. 312 * @param pkt The writeback request. 313 */ 314 void doWriteback(PacketPtr pkt); 315 316 /** 317 * Return whether there are any outstanding misses. 318 */ 319 bool outstandingMisses() const 320 { 321 return mshrQueue.allocated != 0; 322 } 323 324 CacheBlk *findBlock(Addr addr) { 325 return tags->findBlock(addr); 326 } 327 328 bool inCache(Addr addr) { 329 return (tags->findBlock(addr) != 0); 330 } 331 332 bool inMissQueue(Addr addr) { 333 return (mshrQueue.findMatch(addr) != 0); 334 } 335}; 336 337#endif // __CACHE_HH__ 338