cache.hh revision 8985:4b517873c9ae
1/* 2 * Copyright (c) 2012 ARM Limited 3 * All rights reserved. 4 * 5 * The license below extends only to copyright in the software and shall 6 * not be construed as granting a license to any other intellectual 7 * property including but not limited to intellectual property relating 8 * to a hardware implementation of the functionality of the software 9 * licensed hereunder. You may use the software subject to the license 10 * terms below provided that you ensure that this notice is replicated 11 * unmodified and in its entirety in all distributions of the software, 12 * modified or unmodified, in source code or in binary form. 13 * 14 * Copyright (c) 2002-2005 The Regents of The University of Michigan 15 * All rights reserved. 16 * 17 * Redistribution and use in source and binary forms, with or without 18 * modification, are permitted provided that the following conditions are 19 * met: redistributions of source code must retain the above copyright 20 * notice, this list of conditions and the following disclaimer; 21 * redistributions in binary form must reproduce the above copyright 22 * notice, this list of conditions and the following disclaimer in the 23 * documentation and/or other materials provided with the distribution; 24 * neither the name of the copyright holders nor the names of its 25 * contributors may be used to endorse or promote products derived from 26 * this software without specific prior written permission. 27 * 28 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 29 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 30 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR 31 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT 32 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 33 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT 34 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 35 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 36 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 37 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE 38 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 39 * 40 * Authors: Erik Hallnor 41 * Dave Greene 42 * Steve Reinhardt 43 * Ron Dreslinski 44 * Andreas Hansson 45 */ 46 47/** 48 * @file 49 * Describes a cache based on template policies. 50 */ 51 52#ifndef __CACHE_HH__ 53#define __CACHE_HH__ 54 55#include "base/misc.hh" // fatal, panic, and warn 56#include "mem/cache/base.hh" 57#include "mem/cache/blk.hh" 58#include "mem/cache/mshr.hh" 59#include "sim/eventq.hh" 60 61//Forward decleration 62class BasePrefetcher; 63 64/** 65 * A template-policy based cache. The behavior of the cache can be altered by 66 * supplying different template policies. TagStore handles all tag and data 67 * storage @sa TagStore. 68 */ 69template <class TagStore> 70class Cache : public BaseCache 71{ 72 public: 73 /** Define the type of cache block to use. */ 74 typedef typename TagStore::BlkType BlkType; 75 /** A typedef for a list of BlkType pointers. */ 76 typedef typename TagStore::BlkList BlkList; 77 78 protected: 79 80 /** 81 * The CPU-side port extends the base cache slave port with access 82 * functions for functional, atomic and timing requests. 83 */ 84 class CpuSidePort : public CacheSlavePort 85 { 86 private: 87 88 // a pointer to our specific cache implementation 89 Cache<TagStore> *cache; 90 91 protected: 92 93 virtual bool recvTimingSnoopResp(PacketPtr pkt); 94 95 virtual bool recvTimingReq(PacketPtr pkt); 96 97 virtual Tick recvAtomic(PacketPtr pkt); 98 99 virtual void recvFunctional(PacketPtr pkt); 100 101 virtual unsigned deviceBlockSize() const 102 { return cache->getBlockSize(); } 103 104 virtual AddrRangeList getAddrRanges(); 105 106 public: 107 108 CpuSidePort(const std::string &_name, Cache<TagStore> *_cache, 109 const std::string &_label); 110 111 }; 112 113 /** 114 * Override the default behaviour of sendDeferredPacket to enable 115 * the memory-side cache port to also send requests based on the 116 * current MSHR status. This queue has a pointer to our specific 117 * cache implementation and is used by the MemSidePort. 118 */ 119 class MemSidePacketQueue : public MasterPacketQueue 120 { 121 122 protected: 123 124 Cache<TagStore> &cache; 125 126 public: 127 128 MemSidePacketQueue(Cache<TagStore> &cache, MasterPort &port, 129 const std::string &label) : 130 MasterPacketQueue(cache, port, label), cache(cache) { } 131 132 /** 133 * Override the normal sendDeferredPacket and do not only 134 * consider the transmit list (used for responses), but also 135 * requests. 136 */ 137 virtual void sendDeferredPacket(); 138 139 }; 140 141 /** 142 * The memory-side port extends the base cache master port with 143 * access functions for functional, atomic and timing snoops. 144 */ 145 class MemSidePort : public CacheMasterPort 146 { 147 private: 148 149 /** The cache-specific queue. */ 150 MemSidePacketQueue _queue; 151 152 // a pointer to our specific cache implementation 153 Cache<TagStore> *cache; 154 155 protected: 156 157 virtual void recvTimingSnoopReq(PacketPtr pkt); 158 159 virtual bool recvTimingResp(PacketPtr pkt); 160 161 virtual Tick recvAtomicSnoop(PacketPtr pkt); 162 163 virtual void recvFunctionalSnoop(PacketPtr pkt); 164 165 virtual unsigned deviceBlockSize() const 166 { return cache->getBlockSize(); } 167 168 public: 169 170 MemSidePort(const std::string &_name, Cache<TagStore> *_cache, 171 const std::string &_label); 172 }; 173 174 /** Tag and data Storage */ 175 TagStore *tags; 176 177 /** Prefetcher */ 178 BasePrefetcher *prefetcher; 179 180 /** Temporary cache block for occasional transitory use */ 181 BlkType *tempBlock; 182 183 /** 184 * This cache should allocate a block on a line-sized write miss. 185 */ 186 const bool doFastWrites; 187 188 /** 189 * Notify the prefetcher on every access, not just misses. 190 */ 191 const bool prefetchOnAccess; 192 193 /** 194 * Does all the processing necessary to perform the provided request. 195 * @param pkt The memory request to perform. 196 * @param lat The latency of the access. 197 * @param writebacks List for any writebacks that need to be performed. 198 * @param update True if the replacement data should be updated. 199 * @return Boolean indicating whether the request was satisfied. 200 */ 201 bool access(PacketPtr pkt, BlkType *&blk, 202 int &lat, PacketList &writebacks); 203 204 /** 205 *Handle doing the Compare and Swap function for SPARC. 206 */ 207 void cmpAndSwap(BlkType *blk, PacketPtr pkt); 208 209 /** 210 * Find a block frame for new block at address addr, assuming that 211 * the block is not currently in the cache. Append writebacks if 212 * any to provided packet list. Return free block frame. May 213 * return NULL if there are no replaceable blocks at the moment. 214 */ 215 BlkType *allocateBlock(Addr addr, PacketList &writebacks); 216 217 /** 218 * Populates a cache block and handles all outstanding requests for the 219 * satisfied fill request. This version takes two memory requests. One 220 * contains the fill data, the other is an optional target to satisfy. 221 * @param pkt The memory request with the fill data. 222 * @param blk The cache block if it already exists. 223 * @param writebacks List for any writebacks that need to be performed. 224 * @return Pointer to the new cache block. 225 */ 226 BlkType *handleFill(PacketPtr pkt, BlkType *blk, 227 PacketList &writebacks); 228 229 void satisfyCpuSideRequest(PacketPtr pkt, BlkType *blk, 230 bool deferred_response = false, 231 bool pending_downgrade = false); 232 bool satisfyMSHR(MSHR *mshr, PacketPtr pkt, BlkType *blk); 233 234 void doTimingSupplyResponse(PacketPtr req_pkt, uint8_t *blk_data, 235 bool already_copied, bool pending_inval); 236 237 /** 238 * Sets the blk to the new state. 239 * @param blk The cache block being snooped. 240 * @param new_state The new coherence state for the block. 241 */ 242 void handleSnoop(PacketPtr ptk, BlkType *blk, 243 bool is_timing, bool is_deferred, bool pending_inval); 244 245 /** 246 * Create a writeback request for the given block. 247 * @param blk The block to writeback. 248 * @return The writeback request for the block. 249 */ 250 PacketPtr writebackBlk(BlkType *blk); 251 252 public: 253 /** Instantiates a basic cache object. */ 254 Cache(const Params *p, TagStore *tags); 255 256 void regStats(); 257 258 /** 259 * Performs the access specified by the request. 260 * @param pkt The request to perform. 261 * @return The result of the access. 262 */ 263 bool timingAccess(PacketPtr pkt); 264 265 /** 266 * Performs the access specified by the request. 267 * @param pkt The request to perform. 268 * @return The result of the access. 269 */ 270 Tick atomicAccess(PacketPtr pkt); 271 272 /** 273 * Performs the access specified by the request. 274 * @param pkt The request to perform. 275 * @param fromCpuSide from the CPU side port or the memory side port 276 */ 277 void functionalAccess(PacketPtr pkt, bool fromCpuSide); 278 279 /** 280 * Handles a response (cache line fill/write ack) from the bus. 281 * @param pkt The request being responded to. 282 */ 283 void handleResponse(PacketPtr pkt); 284 285 /** 286 * Snoops bus transactions to maintain coherence. 287 * @param pkt The current bus transaction. 288 */ 289 void snoopTiming(PacketPtr pkt); 290 291 /** 292 * Snoop for the provided request in the cache and return the estimated 293 * time of completion. 294 * @param pkt The memory request to snoop 295 * @return The estimated completion time. 296 */ 297 Tick snoopAtomic(PacketPtr pkt); 298 299 /** 300 * Squash all requests associated with specified thread. 301 * intended for use by I-cache. 302 * @param threadNum The thread to squash. 303 */ 304 void squash(int threadNum); 305 306 /** 307 * Generate an appropriate downstream bus request packet for the 308 * given parameters. 309 * @param cpu_pkt The upstream request that needs to be satisfied. 310 * @param blk The block currently in the cache corresponding to 311 * cpu_pkt (NULL if none). 312 * @param needsExclusive Indicates that an exclusive copy is required 313 * even if the request in cpu_pkt doesn't indicate that. 314 * @return A new Packet containing the request, or NULL if the 315 * current request in cpu_pkt should just be forwarded on. 316 */ 317 PacketPtr getBusPacket(PacketPtr cpu_pkt, BlkType *blk, 318 bool needsExclusive); 319 320 /** 321 * Return the next MSHR to service, either a pending miss from the 322 * mshrQueue, a buffered write from the write buffer, or something 323 * from the prefetcher. This function is responsible for 324 * prioritizing among those sources on the fly. 325 */ 326 MSHR *getNextMSHR(); 327 328 /** 329 * Selects an outstanding request to service. Called when the 330 * cache gets granted the downstream bus in timing mode. 331 * @return The request to service, NULL if none found. 332 */ 333 PacketPtr getTimingPacket(); 334 335 /** 336 * Marks a request as in service (sent on the bus). This can have side 337 * effect since storage for no response commands is deallocated once they 338 * are successfully sent. 339 * @param pkt The request that was sent on the bus. 340 */ 341 void markInService(MSHR *mshr, PacketPtr pkt = 0); 342 343 /** 344 * Perform the given writeback request. 345 * @param pkt The writeback request. 346 */ 347 void doWriteback(PacketPtr pkt); 348 349 /** 350 * Return whether there are any outstanding misses. 351 */ 352 bool outstandingMisses() const 353 { 354 return mshrQueue.allocated != 0; 355 } 356 357 CacheBlk *findBlock(Addr addr) { 358 return tags->findBlock(addr); 359 } 360 361 bool inCache(Addr addr) { 362 return (tags->findBlock(addr) != 0); 363 } 364 365 bool inMissQueue(Addr addr) { 366 return (mshrQueue.findMatch(addr) != 0); 367 } 368 369 /** 370 * Find next request ready time from among possible sources. 371 */ 372 Tick nextMSHRReadyTime(); 373 374 /** serialize the state of the caches 375 * We currently don't support checkpointing cache state, so this panics. 376 */ 377 virtual void serialize(std::ostream &os); 378 void unserialize(Checkpoint *cp, const std::string §ion); 379}; 380 381#endif // __CACHE_HH__ 382