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 */
45
46/**
47 * @file
48 * Describes a cache based on template policies.
49 */
50
51#ifndef __CACHE_HH__
52#define __CACHE_HH__
53
54#include "base/misc.hh" // fatal, panic, and warn
55#include "mem/cache/base.hh"
56#include "mem/cache/blk.hh"
57#include "mem/cache/mshr.hh"
58#include "sim/eventq.hh"
59
60//Forward decleration
61class BasePrefetcher;
62
63/**
64 * A template-policy based cache. The behavior of the cache can be altered by
65 * supplying different template policies. TagStore handles all tag and data
66 * storage @sa TagStore.
67 */
68template <class TagStore>
69class Cache : public BaseCache
70{
71 public:
72 /** Define the type of cache block to use. */
73 typedef typename TagStore::BlkType BlkType;
74 /** A typedef for a list of BlkType pointers. */
75 typedef typename TagStore::BlkList BlkList;
76
77 protected:
78
79 class CpuSidePort : public CachePort
80 {
81 public:
82 CpuSidePort(const std::string &_name,
83 Cache<TagStore> *_cache,
84 const std::string &_label);
85
86 // BaseCache::CachePort just has a BaseCache *; this function
87 // lets us get back the type info we lost when we stored the
88 // cache pointer there.
89 Cache<TagStore> *myCache() {
90 return static_cast<Cache<TagStore> *>(cache);
91 }
92
93 virtual AddrRangeList getAddrRanges();
94
95 virtual bool recvTiming(PacketPtr pkt);
96
97 virtual Tick recvAtomic(PacketPtr pkt);
98
99 virtual void recvFunctional(PacketPtr pkt);
100 };
101
102 class MemSidePort : public CachePort
103 {
104 public:
105 MemSidePort(const std::string &_name,
106 Cache<TagStore> *_cache,
107 const std::string &_label);
108
109 // BaseCache::CachePort just has a BaseCache *; this function
110 // lets us get back the type info we lost when we stored the
111 // cache pointer there.
112 Cache<TagStore> *myCache() {
113 return static_cast<Cache<TagStore> *>(cache);
114 }
115
116 void sendPacket();
117
118 void processSendEvent();
119
120 virtual bool isSnooping();
121
122 virtual bool recvTiming(PacketPtr pkt);
123
124 virtual void recvRetry();
125
126 virtual Tick recvAtomic(PacketPtr pkt);
127
128 virtual void recvFunctional(PacketPtr pkt);
129
130 typedef EventWrapper<MemSidePort, &MemSidePort::processSendEvent>
131 SendEvent;
132 };
133
134 /** Tag and data Storage */
135 TagStore *tags;
136
137 /** Prefetcher */
138 BasePrefetcher *prefetcher;
139
140 /** Temporary cache block for occasional transitory use */
141 BlkType *tempBlock;
142
143 /**
144 * This cache should allocate a block on a line-sized write miss.
145 */
146 const bool doFastWrites;
147
148 /**
149 * Notify the prefetcher on every access, not just misses.
150 */
151 const bool prefetchOnAccess;
152
153 /**
154 * Does all the processing necessary to perform the provided request.
155 * @param pkt The memory request to perform.
156 * @param lat The latency of the access.
157 * @param writebacks List for any writebacks that need to be performed.
158 * @param update True if the replacement data should be updated.
159 * @return Boolean indicating whether the request was satisfied.
160 */
161 bool access(PacketPtr pkt, BlkType *&blk,
162 int &lat, PacketList &writebacks);
163
164 /**
165 *Handle doing the Compare and Swap function for SPARC.
166 */
167 void cmpAndSwap(BlkType *blk, PacketPtr pkt);
168
169 /**
170 * Find a block frame for new block at address addr, assuming that
171 * the block is not currently in the cache. Append writebacks if
172 * any to provided packet list. Return free block frame. May
173 * return NULL if there are no replaceable blocks at the moment.
174 */
175 BlkType *allocateBlock(Addr addr, PacketList &writebacks);
176
177 /**
178 * Populates a cache block and handles all outstanding requests for the
179 * satisfied fill request. This version takes two memory requests. One
180 * contains the fill data, the other is an optional target to satisfy.
181 * @param pkt The memory request with the fill data.
182 * @param blk The cache block if it already exists.
183 * @param writebacks List for any writebacks that need to be performed.
184 * @return Pointer to the new cache block.
185 */
186 BlkType *handleFill(PacketPtr pkt, BlkType *blk,
187 PacketList &writebacks);
188
189 void satisfyCpuSideRequest(PacketPtr pkt, BlkType *blk,
190 bool deferred_response = false,
191 bool pending_downgrade = false);
192 bool satisfyMSHR(MSHR *mshr, PacketPtr pkt, BlkType *blk);
193
194 void doTimingSupplyResponse(PacketPtr req_pkt, uint8_t *blk_data,
195 bool already_copied, bool pending_inval);
196
197 /**
198 * Sets the blk to the new state.
199 * @param blk The cache block being snooped.
200 * @param new_state The new coherence state for the block.
201 */
202 void handleSnoop(PacketPtr ptk, BlkType *blk,
203 bool is_timing, bool is_deferred, bool pending_inval);
204
205 /**
206 * Create a writeback request for the given block.
207 * @param blk The block to writeback.
208 * @return The writeback request for the block.
209 */
210 PacketPtr writebackBlk(BlkType *blk);
211
212 public:
213 /** Instantiates a basic cache object. */
214 Cache(const Params *p, TagStore *tags);
215
216 virtual Port *getPort(const std::string &if_name, int idx = -1);
217
218 void regStats();
219
220 /**
221 * Performs the access specified by the request.
222 * @param pkt The request to perform.
223 * @return The result of the access.
224 */
225 bool timingAccess(PacketPtr pkt);
226
227 /**
228 * Performs the access specified by the request.
229 * @param pkt The request to perform.
230 * @return The result of the access.
231 */
232 Tick atomicAccess(PacketPtr pkt);
233
234 /**
235 * Performs the access specified by the request.
236 * @param pkt The request to perform.
237 * @param fromCpuSide from the CPU side port or the memory side port
238 */
239 void functionalAccess(PacketPtr pkt, bool fromCpuSide);
240
241 /**
242 * Handles a response (cache line fill/write ack) from the bus.
243 * @param pkt The request being responded to.
244 */
245 void handleResponse(PacketPtr pkt);
246
247 /**
248 * Snoops bus transactions to maintain coherence.
249 * @param pkt The current bus transaction.
250 */
251 void snoopTiming(PacketPtr pkt);
252
253 /**
254 * Snoop for the provided request in the cache and return the estimated
255 * time of completion.
256 * @param pkt The memory request to snoop
257 * @return The estimated completion time.
258 */
259 Tick snoopAtomic(PacketPtr pkt);
260
261 /**
262 * Squash all requests associated with specified thread.
263 * intended for use by I-cache.
264 * @param threadNum The thread to squash.
265 */
266 void squash(int threadNum);
267
268 /**
269 * Generate an appropriate downstream bus request packet for the
270 * given parameters.
271 * @param cpu_pkt The upstream request that needs to be satisfied.
272 * @param blk The block currently in the cache corresponding to
273 * cpu_pkt (NULL if none).
274 * @param needsExclusive Indicates that an exclusive copy is required
275 * even if the request in cpu_pkt doesn't indicate that.
276 * @return A new Packet containing the request, or NULL if the
277 * current request in cpu_pkt should just be forwarded on.
278 */
279 PacketPtr getBusPacket(PacketPtr cpu_pkt, BlkType *blk,
280 bool needsExclusive);
281
282 /**
283 * Return the next MSHR to service, either a pending miss from the
284 * mshrQueue, a buffered write from the write buffer, or something
285 * from the prefetcher. This function is responsible for
286 * prioritizing among those sources on the fly.
287 */
288 MSHR *getNextMSHR();
289
290 /**
291 * Selects an outstanding request to service. Called when the
292 * cache gets granted the downstream bus in timing mode.
293 * @return The request to service, NULL if none found.
294 */
295 PacketPtr getTimingPacket();
296
297 /**
298 * Marks a request as in service (sent on the bus). This can have side
299 * effect since storage for no response commands is deallocated once they
300 * are successfully sent.
301 * @param pkt The request that was sent on the bus.
302 */
303 void markInService(MSHR *mshr, PacketPtr pkt = 0);
304
305 /**
306 * Perform the given writeback request.
307 * @param pkt The writeback request.
308 */
309 void doWriteback(PacketPtr pkt);
310
311 /**
312 * Return whether there are any outstanding misses.
313 */
314 bool outstandingMisses() const
315 {
316 return mshrQueue.allocated != 0;
317 }
318
319 CacheBlk *findBlock(Addr addr) {
320 return tags->findBlock(addr);
321 }
322
323 bool inCache(Addr addr) {
324 return (tags->findBlock(addr) != 0);
325 }
326
327 bool inMissQueue(Addr addr) {
328 return (mshrQueue.findMatch(addr) != 0);
329 }
330
331 /**
332 * Find next request ready time from among possible sources.
333 */
334 Tick nextMSHRReadyTime();
335};
336
337#endif // __CACHE_HH__