1/*
2 * Copyright (c) 2012-2014,2017 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) 2003-2005,2014 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 */
42
43/**
44 * @file
45 * Declaration of a base set associative tag store.
46 */
47
48#ifndef __MEM_CACHE_TAGS_BASE_SET_ASSOC_HH__
49#define __MEM_CACHE_TAGS_BASE_SET_ASSOC_HH__
50
51#include <functional>
52#include <string>
53#include <vector>
54
55#include "base/logging.hh"
56#include "base/types.hh"
57#include "debug/CacheRepl.hh"
58#include "mem/cache/base.hh"
59#include "mem/cache/blk.hh"
60#include "mem/cache/replacement_policies/base.hh"
61#include "mem/cache/tags/base.hh"
62#include "mem/cache/tags/cacheset.hh"
63#include "params/BaseSetAssoc.hh"
64
65/**
66 * A BaseSetAssoc cache tag store.
67 * @sa \ref gem5MemorySystem "gem5 Memory System"
68 *
69 * The BaseSetAssoc placement policy divides the cache into s sets of w
70 * cache lines (ways). A cache line is mapped onto a set, and can be placed
71 * into any of the ways of this set.
72 */
73class BaseSetAssoc : public BaseTags
74{
75 public:
76 /** Typedef the block type used in this tag store. */
77 typedef CacheBlk BlkType;
78 /** Typedef the set type used in this tag store. */
79 typedef CacheSet<CacheBlk> SetType;
80
81 protected:
82 /** The associativity of the cache. */
83 const unsigned assoc;
84 /** The allocatable associativity of the cache (alloc mask). */
85 unsigned allocAssoc;
86
87 /** The cache blocks. */
88 std::vector<BlkType> blks;
89
90 /** The number of sets in the cache. */
91 const unsigned numSets;
92
93 /** Whether tags and data are accessed sequentially. */
94 const bool sequentialAccess;
95
96 /** The cache sets. */
97 std::vector<SetType> sets;
98
99 /** The amount to shift the address to get the set. */
100 int setShift;
101 /** The amount to shift the address to get the tag. */
102 int tagShift;
103 /** Mask out all bits that aren't part of the set index. */
104 unsigned setMask;
105
106 /** Replacement policy */
107 BaseReplacementPolicy *replacementPolicy;
108
109 public:
110 /** Convenience typedef. */
111 typedef BaseSetAssocParams Params;
112
113 /**
114 * Construct and initialize this tag store.
115 */
116 BaseSetAssoc(const Params *p);
117
118 /**
119 * Destructor
120 */
121 virtual ~BaseSetAssoc() {};
122
123 /**
124 * Initialize blocks and set the parent cache back pointer.
125 *
126 * @param _cache Pointer to parent cache.
127 */
128 void init(BaseCache *_cache) override;
129
130 /**
131 * This function updates the tags when a block is invalidated. It also
132 * updates the replacement data.
133 *
134 * @param blk The block to invalidate.
135 */
136 void invalidate(CacheBlk *blk) override;
137
138 /**
139 * Access block and update replacement data. May not succeed, in which case
140 * nullptr is returned. This has all the implications of a cache
141 * access and should only be used as such. Returns the access latency as a
142 * side effect.
143 * @param addr The address to find.
144 * @param is_secure True if the target memory space is secure.
145 * @param lat The access latency.
146 * @return Pointer to the cache block if found.
147 */
148 CacheBlk* accessBlock(Addr addr, bool is_secure, Cycles &lat) override
149 {
150 BlkType *blk = findBlock(addr, is_secure);
151
152 // Access all tags in parallel, hence one in each way. The data side
153 // either accesses all blocks in parallel, or one block sequentially on
154 // a hit. Sequential access with a miss doesn't access data.
155 tagAccesses += allocAssoc;
156 if (sequentialAccess) {
157 if (blk != nullptr) {
158 dataAccesses += 1;
159 }
160 } else {
161 dataAccesses += allocAssoc;
162 }
163
164 if (blk != nullptr) {
165 // If a cache hit
166 lat = accessLatency;
167 // Check if the block to be accessed is available. If not,
168 // apply the accessLatency on top of block->whenReady.
169 if (blk->whenReady > curTick() &&
170 cache->ticksToCycles(blk->whenReady - curTick()) >
171 accessLatency) {
172 lat = cache->ticksToCycles(blk->whenReady - curTick()) +
173 accessLatency;
174 }
175
176 // Update number of references to accessed block
177 blk->refCount++;
178
179 // Update replacement data of accessed block
180 replacementPolicy->touch(blk->replacementData);
181 } else {
182 // If a cache miss
183 lat = lookupLatency;
184 }
185
186 return blk;
187 }
188
189 /**
190 * Finds the given address in the cache, do not update replacement data.
191 * i.e. This is a no-side-effect find of a block.
192 *
193 * @param addr The address to find.
194 * @param is_secure True if the target memory space is secure.
195 * @return Pointer to the cache block if found.
196 */
197 CacheBlk* findBlock(Addr addr, bool is_secure) const override;
198
199 /**
200 * Find a block given set and way.
201 *
202 * @param set The set of the block.
203 * @param way The way of the block.
204 * @return The block.
205 */
206 ReplaceableEntry* findBlockBySetAndWay(int set, int way) const override;
207
208 /**
209 * Find replacement victim based on address. The list of evicted blocks
210 * only contains the victim.
211 *
212 * @param addr Address to find a victim for.
213 * @param is_secure True if the target memory space is secure.
214 * @param evict_blks Cache blocks to be evicted.
215 * @return Cache block to be replaced.
216 */
217 CacheBlk* findVictim(Addr addr, const bool is_secure,
218 std::vector<CacheBlk*>& evict_blks) const override
219 {
220 // Get possible locations for the victim block
221 std::vector<CacheBlk*> locations = getPossibleLocations(addr);
222
223 // Choose replacement victim from replacement candidates
224 CacheBlk* victim = static_cast<CacheBlk*>(replacementPolicy->getVictim(
225 std::vector<ReplaceableEntry*>(
226 locations.begin(), locations.end())));
227
228 // There is only one eviction for this replacement
229 evict_blks.push_back(victim);
230
231 DPRINTF(CacheRepl, "set %x, way %x: selecting blk for replacement\n",
232 victim->set, victim->way);
233
234 return victim;
235 }
236
237 /**
238 * Find all possible block locations for insertion and replacement of
239 * an address. Should be called immediately before ReplacementPolicy's
240 * findVictim() not to break cache resizing.
241 * Returns blocks in all ways belonging to the set of the address.
242 *
243 * @param addr The addr to a find possible locations for.
244 * @return The possible locations.
245 */
246 virtual const std::vector<CacheBlk*> getPossibleLocations(Addr addr) const
247 {
248 return sets[extractSet(addr)].blks;
249 }
250
251 /**
252 * Insert the new block into the cache and update replacement data.
253 *
254 * @param addr Address of the block.
255 * @param is_secure Whether the block is in secure space or not.
256 * @param src_master_ID The source requestor ID.
257 * @param task_ID The new task ID.
258 * @param blk The block to update.
259 */
260 void insertBlock(const Addr addr, const bool is_secure,
261 const int src_master_ID, const uint32_t task_ID,
262 CacheBlk *blk) override
263 {
264 // Insert block
265 BaseTags::insertBlock(addr, is_secure, src_master_ID, task_ID, blk);
266
267 // Increment tag counter
268 tagsInUse++;
269
270 // Update replacement policy
271 replacementPolicy->reset(blk->replacementData);
272 }
273
274 /**
275 * Limit the allocation for the cache ways.
276 * @param ways The maximum number of ways available for replacement.
277 */
278 virtual void setWayAllocationMax(int ways) override
279 {
280 fatal_if(ways < 1, "Allocation limit must be greater than zero");
281 allocAssoc = ways;
282 }
283
284 /**
285 * Get the way allocation mask limit.
286 * @return The maximum number of ways available for replacement.
287 */
288 virtual int getWayAllocationMax() const override
289 {
290 return allocAssoc;
291 }
292
293 /**
294 * Generate the tag from the given address.
295 * @param addr The address to get the tag from.
296 * @return The tag of the address.
297 */
298 Addr extractTag(Addr addr) const override
299 {
300 return (addr >> tagShift);
301 }
302
303 /**
304 * Regenerate the block address from the tag and set.
305 *
306 * @param block The block.
307 * @return the block address.
308 */
309 Addr regenerateBlkAddr(const CacheBlk* blk) const override
310 {
311 return ((blk->tag << tagShift) | ((Addr)blk->set << setShift));
312 }
313
314 void forEachBlk(std::function<void(CacheBlk &)> visitor) override {
315 for (CacheBlk& blk : blks) {
316 visitor(blk);
317 }
318 }
319
320 bool anyBlk(std::function<bool(CacheBlk &)> visitor) override {
321 for (CacheBlk& blk : blks) {
322 if (visitor(blk)) {
323 return true;
324 }
325 }
326 return false;
327 }
328
329 private:
330 /**
331 * Calculate the set index from the address.
332 *
333 * @param addr The address to get the set from.
334 * @return The set index of the address.
335 */
336 int extractSet(Addr addr) const
337 {
338 return ((addr >> setShift) & setMask);
339 }
340};
341
342#endif //__MEM_CACHE_TAGS_BASE_SET_ASSOC_HH__
2 * Copyright (c) 2012-2014,2017 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) 2003-2005,2014 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 */
42
43/**
44 * @file
45 * Declaration of a base set associative tag store.
46 */
47
48#ifndef __MEM_CACHE_TAGS_BASE_SET_ASSOC_HH__
49#define __MEM_CACHE_TAGS_BASE_SET_ASSOC_HH__
50
51#include <functional>
52#include <string>
53#include <vector>
54
55#include "base/logging.hh"
56#include "base/types.hh"
57#include "debug/CacheRepl.hh"
58#include "mem/cache/base.hh"
59#include "mem/cache/blk.hh"
60#include "mem/cache/replacement_policies/base.hh"
61#include "mem/cache/tags/base.hh"
62#include "mem/cache/tags/cacheset.hh"
63#include "params/BaseSetAssoc.hh"
64
65/**
66 * A BaseSetAssoc cache tag store.
67 * @sa \ref gem5MemorySystem "gem5 Memory System"
68 *
69 * The BaseSetAssoc placement policy divides the cache into s sets of w
70 * cache lines (ways). A cache line is mapped onto a set, and can be placed
71 * into any of the ways of this set.
72 */
73class BaseSetAssoc : public BaseTags
74{
75 public:
76 /** Typedef the block type used in this tag store. */
77 typedef CacheBlk BlkType;
78 /** Typedef the set type used in this tag store. */
79 typedef CacheSet<CacheBlk> SetType;
80
81 protected:
82 /** The associativity of the cache. */
83 const unsigned assoc;
84 /** The allocatable associativity of the cache (alloc mask). */
85 unsigned allocAssoc;
86
87 /** The cache blocks. */
88 std::vector<BlkType> blks;
89
90 /** The number of sets in the cache. */
91 const unsigned numSets;
92
93 /** Whether tags and data are accessed sequentially. */
94 const bool sequentialAccess;
95
96 /** The cache sets. */
97 std::vector<SetType> sets;
98
99 /** The amount to shift the address to get the set. */
100 int setShift;
101 /** The amount to shift the address to get the tag. */
102 int tagShift;
103 /** Mask out all bits that aren't part of the set index. */
104 unsigned setMask;
105
106 /** Replacement policy */
107 BaseReplacementPolicy *replacementPolicy;
108
109 public:
110 /** Convenience typedef. */
111 typedef BaseSetAssocParams Params;
112
113 /**
114 * Construct and initialize this tag store.
115 */
116 BaseSetAssoc(const Params *p);
117
118 /**
119 * Destructor
120 */
121 virtual ~BaseSetAssoc() {};
122
123 /**
124 * Initialize blocks and set the parent cache back pointer.
125 *
126 * @param _cache Pointer to parent cache.
127 */
128 void init(BaseCache *_cache) override;
129
130 /**
131 * This function updates the tags when a block is invalidated. It also
132 * updates the replacement data.
133 *
134 * @param blk The block to invalidate.
135 */
136 void invalidate(CacheBlk *blk) override;
137
138 /**
139 * Access block and update replacement data. May not succeed, in which case
140 * nullptr is returned. This has all the implications of a cache
141 * access and should only be used as such. Returns the access latency as a
142 * side effect.
143 * @param addr The address to find.
144 * @param is_secure True if the target memory space is secure.
145 * @param lat The access latency.
146 * @return Pointer to the cache block if found.
147 */
148 CacheBlk* accessBlock(Addr addr, bool is_secure, Cycles &lat) override
149 {
150 BlkType *blk = findBlock(addr, is_secure);
151
152 // Access all tags in parallel, hence one in each way. The data side
153 // either accesses all blocks in parallel, or one block sequentially on
154 // a hit. Sequential access with a miss doesn't access data.
155 tagAccesses += allocAssoc;
156 if (sequentialAccess) {
157 if (blk != nullptr) {
158 dataAccesses += 1;
159 }
160 } else {
161 dataAccesses += allocAssoc;
162 }
163
164 if (blk != nullptr) {
165 // If a cache hit
166 lat = accessLatency;
167 // Check if the block to be accessed is available. If not,
168 // apply the accessLatency on top of block->whenReady.
169 if (blk->whenReady > curTick() &&
170 cache->ticksToCycles(blk->whenReady - curTick()) >
171 accessLatency) {
172 lat = cache->ticksToCycles(blk->whenReady - curTick()) +
173 accessLatency;
174 }
175
176 // Update number of references to accessed block
177 blk->refCount++;
178
179 // Update replacement data of accessed block
180 replacementPolicy->touch(blk->replacementData);
181 } else {
182 // If a cache miss
183 lat = lookupLatency;
184 }
185
186 return blk;
187 }
188
189 /**
190 * Finds the given address in the cache, do not update replacement data.
191 * i.e. This is a no-side-effect find of a block.
192 *
193 * @param addr The address to find.
194 * @param is_secure True if the target memory space is secure.
195 * @return Pointer to the cache block if found.
196 */
197 CacheBlk* findBlock(Addr addr, bool is_secure) const override;
198
199 /**
200 * Find a block given set and way.
201 *
202 * @param set The set of the block.
203 * @param way The way of the block.
204 * @return The block.
205 */
206 ReplaceableEntry* findBlockBySetAndWay(int set, int way) const override;
207
208 /**
209 * Find replacement victim based on address. The list of evicted blocks
210 * only contains the victim.
211 *
212 * @param addr Address to find a victim for.
213 * @param is_secure True if the target memory space is secure.
214 * @param evict_blks Cache blocks to be evicted.
215 * @return Cache block to be replaced.
216 */
217 CacheBlk* findVictim(Addr addr, const bool is_secure,
218 std::vector<CacheBlk*>& evict_blks) const override
219 {
220 // Get possible locations for the victim block
221 std::vector<CacheBlk*> locations = getPossibleLocations(addr);
222
223 // Choose replacement victim from replacement candidates
224 CacheBlk* victim = static_cast<CacheBlk*>(replacementPolicy->getVictim(
225 std::vector<ReplaceableEntry*>(
226 locations.begin(), locations.end())));
227
228 // There is only one eviction for this replacement
229 evict_blks.push_back(victim);
230
231 DPRINTF(CacheRepl, "set %x, way %x: selecting blk for replacement\n",
232 victim->set, victim->way);
233
234 return victim;
235 }
236
237 /**
238 * Find all possible block locations for insertion and replacement of
239 * an address. Should be called immediately before ReplacementPolicy's
240 * findVictim() not to break cache resizing.
241 * Returns blocks in all ways belonging to the set of the address.
242 *
243 * @param addr The addr to a find possible locations for.
244 * @return The possible locations.
245 */
246 virtual const std::vector<CacheBlk*> getPossibleLocations(Addr addr) const
247 {
248 return sets[extractSet(addr)].blks;
249 }
250
251 /**
252 * Insert the new block into the cache and update replacement data.
253 *
254 * @param addr Address of the block.
255 * @param is_secure Whether the block is in secure space or not.
256 * @param src_master_ID The source requestor ID.
257 * @param task_ID The new task ID.
258 * @param blk The block to update.
259 */
260 void insertBlock(const Addr addr, const bool is_secure,
261 const int src_master_ID, const uint32_t task_ID,
262 CacheBlk *blk) override
263 {
264 // Insert block
265 BaseTags::insertBlock(addr, is_secure, src_master_ID, task_ID, blk);
266
267 // Increment tag counter
268 tagsInUse++;
269
270 // Update replacement policy
271 replacementPolicy->reset(blk->replacementData);
272 }
273
274 /**
275 * Limit the allocation for the cache ways.
276 * @param ways The maximum number of ways available for replacement.
277 */
278 virtual void setWayAllocationMax(int ways) override
279 {
280 fatal_if(ways < 1, "Allocation limit must be greater than zero");
281 allocAssoc = ways;
282 }
283
284 /**
285 * Get the way allocation mask limit.
286 * @return The maximum number of ways available for replacement.
287 */
288 virtual int getWayAllocationMax() const override
289 {
290 return allocAssoc;
291 }
292
293 /**
294 * Generate the tag from the given address.
295 * @param addr The address to get the tag from.
296 * @return The tag of the address.
297 */
298 Addr extractTag(Addr addr) const override
299 {
300 return (addr >> tagShift);
301 }
302
303 /**
304 * Regenerate the block address from the tag and set.
305 *
306 * @param block The block.
307 * @return the block address.
308 */
309 Addr regenerateBlkAddr(const CacheBlk* blk) const override
310 {
311 return ((blk->tag << tagShift) | ((Addr)blk->set << setShift));
312 }
313
314 void forEachBlk(std::function<void(CacheBlk &)> visitor) override {
315 for (CacheBlk& blk : blks) {
316 visitor(blk);
317 }
318 }
319
320 bool anyBlk(std::function<bool(CacheBlk &)> visitor) override {
321 for (CacheBlk& blk : blks) {
322 if (visitor(blk)) {
323 return true;
324 }
325 }
326 return false;
327 }
328
329 private:
330 /**
331 * Calculate the set index from the address.
332 *
333 * @param addr The address to get the set from.
334 * @return The set index of the address.
335 */
336 int extractSet(Addr addr) const
337 {
338 return ((addr >> setShift) & setMask);
339 }
340};
341
342#endif //__MEM_CACHE_TAGS_BASE_SET_ASSOC_HH__