2 * Copyright (c) 2012-2014 ARM Limited
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.
14 * Copyright (c) 2003-2005,2014 The Regents of The University of Michigan
15 * All rights reserved.
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.
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.
40 * Authors: Erik Hallnor
45 * Declaration of a base set associative tag store.
48 #ifndef __MEM_CACHE_TAGS_BASESETASSOC_HH__
49 #define __MEM_CACHE_TAGS_BASESETASSOC_HH__
55 #include "mem/cache/tags/base.hh"
56 #include "mem/cache/tags/cacheset.hh"
57 #include "mem/cache/base.hh"
58 #include "mem/cache/blk.hh"
59 #include "mem/packet.hh"
60 #include "params/BaseSetAssoc.hh"
63 * A BaseSetAssoc cache tag store.
64 * @sa \ref gem5MemorySystem "gem5 Memory System"
66 * The BaseSetAssoc tags provide a base, as well as the functionality
67 * common to any set associative tags. Any derived class must implement
68 * the methods related to the specifics of the actual replacment policy.
71 * BlkType* accessBlock();
72 * BlkType* findVictim();
76 class BaseSetAssoc : public BaseTags
79 /** Typedef the block type used in this tag store. */
80 typedef CacheBlk BlkType;
81 /** Typedef for a list of pointers to the local block class. */
82 typedef std::list<BlkType*> BlkList;
83 /** Typedef the set type used in this tag store. */
84 typedef CacheSet<CacheBlk> SetType;
88 /** The associativity of the cache. */
90 /** The allocatable associativity of the cache (alloc mask). */
92 /** The number of sets in the cache. */
93 const unsigned numSets;
94 /** Whether tags and data are accessed sequentially. */
95 const bool sequentialAccess;
97 /** The cache sets. */
100 /** The cache blocks. */
102 /** The data blocks, 1 per cache block. */
105 /** The amount to shift the address to get the set. */
107 /** The amount to shift the address to get the tag. */
109 /** Mask out all bits that aren't part of the set index. */
111 /** Mask out all bits that aren't part of the block offset. */
116 /** Convenience typedef. */
117 typedef BaseSetAssocParams Params;
120 * Construct and initialize this tag store.
122 BaseSetAssoc(const Params *p);
127 virtual ~BaseSetAssoc();
130 * Return the block size.
131 * @return the block size.
140 * Return the subblock size. In the case of BaseSetAssoc it is always
142 * @return The block size.
145 getSubBlockSize() const
151 * Return the number of sets this cache has
152 * @return The number of sets.
155 getNumSets() const override
161 * Return the number of ways this cache has
162 * @return The number of ways.
165 getNumWays() const override
171 * Find the cache block given set and way
172 * @param set The set of the block.
173 * @param way The way of the block.
174 * @return The cache block.
176 CacheBlk *findBlockBySetAndWay(int set, int way) const override;
179 * Invalidate the given block.
180 * @param blk The block to invalidate.
182 void invalidate(CacheBlk *blk) override
185 assert(blk->isValid());
187 assert(blk->srcMasterId < cache->system->maxMasters());
188 occupancies[blk->srcMasterId]--;
189 blk->srcMasterId = Request::invldMasterId;
190 blk->task_id = ContextSwitchTaskId::Unknown;
191 blk->tickInserted = curTick();
195 * Access block and update replacement data. May not succeed, in which case
196 * NULL pointer is returned. This has all the implications of a cache
197 * access and should only be used as such. Returns the access latency as a
199 * @param addr The address to find.
200 * @param is_secure True if the target memory space is secure.
201 * @param asid The address space ID.
202 * @param lat The access latency.
203 * @return Pointer to the cache block if found.
205 CacheBlk* accessBlock(Addr addr, bool is_secure, Cycles &lat,
206 int context_src) override
208 Addr tag = extractTag(addr);
209 int set = extractSet(addr);
210 BlkType *blk = sets[set].findBlk(tag, is_secure);
211 lat = accessLatency;;
213 // Access all tags in parallel, hence one in each way. The data side
214 // either accesses all blocks in parallel, or one block sequentially on
215 // a hit. Sequential access with a miss doesn't access data.
216 tagAccesses += allocAssoc;
217 if (sequentialAccess) {
222 dataAccesses += allocAssoc;
226 if (blk->whenReady > curTick()
227 && cache->ticksToCycles(blk->whenReady - curTick())
229 lat = cache->ticksToCycles(blk->whenReady - curTick());
238 * Finds the given address in the cache, do not update replacement data.
239 * i.e. This is a no-side-effect find of a block.
240 * @param addr The address to find.
241 * @param is_secure True if the target memory space is secure.
242 * @param asid The address space ID.
243 * @return Pointer to the cache block if found.
245 CacheBlk* findBlock(Addr addr, bool is_secure) const override;
248 * Find an invalid block to evict for the address provided.
249 * If there are no invalid blocks, this will return the block
250 * in the least-recently-used position.
251 * @param addr The addr to a find a replacement candidate for.
252 * @return The candidate block.
254 CacheBlk* findVictim(Addr addr) override
257 int set = extractSet(addr);
259 // prefer to evict an invalid block
260 for (int i = 0; i < allocAssoc; ++i) {
261 blk = sets[set].blks[i];
270 * Insert the new block into the cache.
271 * @param pkt Packet holding the address to update
272 * @param blk The block to update.
274 void insertBlock(PacketPtr pkt, CacheBlk *blk) override
276 Addr addr = pkt->getAddr();
277 MasterID master_id = pkt->req->masterId();
278 uint32_t task_id = pkt->req->taskId();
280 if (!blk->isTouched) {
282 blk->isTouched = true;
283 if (!warmedUp && tagsInUse.value() >= warmupBound) {
285 warmupCycle = curTick();
289 // If we're replacing a block that was previously valid update
290 // stats for it. This can't be done in findBlock() because a
291 // found block might not actually be replaced there if the
292 // coherence protocol says it can't be.
293 if (blk->isValid()) {
295 totalRefs += blk->refCount;
299 // deal with evicted block
300 assert(blk->srcMasterId < cache->system->maxMasters());
301 occupancies[blk->srcMasterId]--;
306 blk->isTouched = true;
308 // Set tag for new block. Caller is responsible for setting status.
309 blk->tag = extractTag(addr);
311 // deal with what we are bringing in
312 assert(master_id < cache->system->maxMasters());
313 occupancies[master_id]++;
314 blk->srcMasterId = master_id;
315 blk->task_id = task_id;
316 blk->tickInserted = curTick();
318 // We only need to write into one tag and one data block.
324 * Limit the allocation for the cache ways.
325 * @param ways The maximum number of ways available for replacement.
327 virtual void setWayAllocationMax(int ways) override
329 fatal_if(ways < 1, "Allocation limit must be greater than zero");
334 * Get the way allocation mask limit.
335 * @return The maximum number of ways available for replacement.
337 virtual int getWayAllocationMax() const override
343 * Generate the tag from the given address.
344 * @param addr The address to get the tag from.
345 * @return The tag of the address.
347 Addr extractTag(Addr addr) const override
349 return (addr >> tagShift);
353 * Calculate the set index from the address.
354 * @param addr The address to get the set from.
355 * @return The set index of the address.
357 int extractSet(Addr addr) const override
359 return ((addr >> setShift) & setMask);
363 * Align an address to the block size.
364 * @param addr the address to align.
365 * @return The block address.
367 Addr blkAlign(Addr addr) const
369 return (addr & ~(Addr)blkMask);
373 * Regenerate the block address from the tag.
374 * @param tag The tag of the block.
375 * @param set The set of the block.
376 * @return The block address.
378 Addr regenerateBlkAddr(Addr tag, unsigned set) const override
380 return ((tag << tagShift) | ((Addr)set << setShift));
384 * Called at end of simulation to complete average block reference stats.
386 void cleanupRefs() override;
389 * Print all tags used
391 std::string print() const override;
394 * Called prior to dumping stats to compute task occupancy
396 void computeStats() override;
399 * Visit each block in the tag store and apply a visitor to the
402 * The visitor should be a function (or object that behaves like a
403 * function) that takes a cache block reference as its parameter
404 * and returns a bool. A visitor can request the traversal to be
405 * stopped by returning false, returning true causes it to be
406 * called for the next block in the tag store.
408 * \param visitor Visitor to call on each block.
410 void forEachBlk(CacheBlkVisitor &visitor) override {
411 for (unsigned i = 0; i < numSets * assoc; ++i) {
412 if (!visitor(blks[i]))
418 #endif // __MEM_CACHE_TAGS_BASESETASSOC_HH__