1/*
2 * Copyright (c) 2018 Inria
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;

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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: Daniel Carvalho
29 */
30
31/**
32 * @file
33 * Definitions of a base set associative sector tag store.
34 */
35
36#include "mem/cache/tags/sector_tags.hh"
37
38#include <cassert>
39#include <memory>
40#include <string>
41
42#include "base/intmath.hh"
43#include "base/logging.hh"
44#include "base/types.hh"
45#include "debug/CacheRepl.hh"
46#include "mem/cache/base.hh"
47#include "mem/cache/replacement_policies/base.hh"
48
49SectorTags::SectorTags(const SectorTagsParams *p)
50 : BaseTags(p), assoc(p->assoc), allocAssoc(p->assoc),
51 sequentialAccess(p->sequential_access),
52 replacementPolicy(p->replacement_policy),
53 numBlocksPerSector(p->num_blocks_per_sector),
54 numSectors(numBlocks / p->num_blocks_per_sector),
55 numSets(numSectors / p->assoc),
56 blks(numBlocks), secBlks(numSectors), sets(numSets),
57 sectorShift(floorLog2(blkSize)),
58 setShift(sectorShift + floorLog2(numBlocksPerSector)),
59 tagShift(setShift + floorLog2(numSets)),
60 sectorMask(numBlocksPerSector - 1), setMask(numSets - 1)
61{
62 // Check parameters
63 fatal_if(blkSize < 4 || !isPowerOf2(blkSize),
64 "Block size must be at least 4 and a power of 2");
65 fatal_if(!isPowerOf2(numSets),
66 "# of sets must be non-zero and a power of 2");
67 fatal_if(!isPowerOf2(numBlocksPerSector),
68 "# of blocks per sector must be non-zero and a power of 2");
69 fatal_if(assoc <= 0, "associativity must be greater than zero");
70}
71
72void
73SectorTags::init(BaseCache* cache)
74{
75 // Set parent cache
76 setCache(cache);
77
78 // Initialize all sets
79 unsigned sec_blk_index = 0; // index into sector blks array
80 unsigned blk_index = 0; // index into blks array
81 for (unsigned i = 0; i < numSets; ++i) {
82 sets[i].resize(assoc);
83
84 // Initialize all sectors in this set
85 for (unsigned j = 0; j < assoc; ++j) {
86 // Select block within the set to be linked
87 SectorBlk*& sec_blk = sets[i][j];
88
89 // Locate next cache sector
90 sec_blk = &secBlks[sec_blk_index];
91
92 // Associate a replacement data entry to the sector
93 sec_blk->replacementData = replacementPolicy->instantiateEntry();
94
95 // Set its index
96 sec_blk->setPosition(i, j);
97
98 // Initialize all blocks in this sector
99 sec_blk->blks.resize(numBlocksPerSector);
100 for (unsigned k = 0; k < numBlocksPerSector; ++k){
101 // Select block within the set to be linked
102 SectorSubBlk*& blk = sec_blk->blks[k];
103
104 // Locate next cache block
105 blk = &blks[blk_index];
106
107 // Associate a data chunk to the block
108 blk->data = &dataBlks[blkSize*blk_index];
109
110 // Associate sector block to this block
111 blk->setSectorBlock(sec_blk);
112
113 // Associate the sector replacement data to this block
114 blk->replacementData = sec_blk->replacementData;
115
116 // Set its index and sector offset
117 blk->setPosition(i, j);
118 blk->setSectorOffset(k);
119
120 // Update block index
121 ++blk_index;
122 }
123
124 // Update sector block index
125 ++sec_blk_index;
126 }
127 }
128}
129
130void
131SectorTags::invalidate(CacheBlk *blk)
132{
133 BaseTags::invalidate(blk);

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191 } else {
192 // If a cache miss
193 lat = lookupLatency;
194 }
195
196 return blk;
197}
198
199std::vector<ReplaceableEntry*>
200SectorTags::getPossibleLocations(const Addr addr) const
201{
202 std::vector<ReplaceableEntry*> locations;
203 for (const auto& blk : sets[extractSet(addr)]) {
204 locations.push_back(static_cast<ReplaceableEntry*>(blk));
205 }
206 return locations;
207}
208
209void
210SectorTags::insertBlock(const Addr addr, const bool is_secure,
211 const int src_master_ID, const uint32_t task_ID,
212 CacheBlk *blk)
213{
214 // Do common block insertion functionality
215 BaseTags::insertBlock(addr, is_secure, src_master_ID, task_ID, blk);
216

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238{
239 // Extract sector tag
240 const Addr tag = extractTag(addr);
241
242 // The address can only be mapped to a specific location of a sector
243 // due to sectors being composed of contiguous-address entries
244 const Addr offset = extractSectorOffset(addr);
245
246 // Find all possible sector locations for the given address
247 const std::vector<ReplaceableEntry*> locations =
248 getPossibleLocations(addr);
249
250 // Search for block
251 for (const auto& sector : locations) {
252 auto blk = static_cast<SectorBlk*>(sector)->blks[offset];
253 if (blk->getTag() == tag && blk->isValid() &&
254 blk->isSecure() == is_secure) {
255 return blk;
256 }
257 }
258
259 // Did not find block
260 return nullptr;
261}
262
263ReplaceableEntry*
264SectorTags::findBlockBySetAndWay(int set, int way) const
265{
266 return sets[set][way];
267}
268
269CacheBlk*
270SectorTags::findVictim(Addr addr, const bool is_secure,
271 std::vector<CacheBlk*>& evict_blks) const
272{
273 // Get all possible locations of this sector
274 const std::vector<ReplaceableEntry*> sector_locations =
275 getPossibleLocations(addr);
276
277 // Check if the sector this address belongs to has been allocated
278 Addr tag = extractTag(addr);
279 SectorBlk* victim_sector = nullptr;
280 for (const auto& sector : sector_locations) {
281 SectorBlk* sector_blk = static_cast<SectorBlk*>(sector);
282 if ((tag == sector_blk->getTag()) && sector_blk->isValid() &&
283 (is_secure == sector_blk->isSecure())){
284 victim_sector = sector_blk;
285 break;
286 }
287 }
288
289 // If the sector is not present
290 if (victim_sector == nullptr){
291 // Choose replacement victim from replacement candidates
292 victim_sector = static_cast<SectorBlk*>(replacementPolicy->getVictim(
293 sector_locations));
294 }
295
296 // Get the location of the victim block within the sector
297 SectorSubBlk* victim = victim_sector->blks[extractSectorOffset(addr)];
298
299 // Get evicted blocks. Blocks are only evicted if the sectors mismatch and
300 // the currently existing sector is valid.
301 if ((tag == victim_sector->getTag()) &&
302 (is_secure == victim_sector->isSecure())){
303 // It would be a hit if victim was valid, and upgrades do not call
304 // findVictim, so it cannot happen

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312
313 DPRINTF(CacheRepl, "set %x, way %x, sector offset %x: selecting blk " \
314 "for replacement\n", victim->getSet(), victim->getWay(),
315 victim->getSectorOffset());
316
317 return victim;
318}
319
320Addr
321SectorTags::extractTag(Addr addr) const
322{
323 return addr >> tagShift;
324}
325
326int
327SectorTags::extractSet(Addr addr) const
328{
329 return (addr >> setShift) & setMask;
330}
331
332int
333SectorTags::extractSectorOffset(Addr addr) const
334{
335 return (addr >> sectorShift) & sectorMask;
336}
337
338Addr
339SectorTags::regenerateBlkAddr(const CacheBlk* blk) const
340{
341 const SectorSubBlk* blk_cast = static_cast<const SectorSubBlk*>(blk);
342 const Addr set = blk_cast->getSectorBlock()->getSet() << setShift;
343 return ((blk_cast->getTag() << tagShift) | set |
344 ((Addr)blk_cast->getSectorOffset() << sectorShift));
345}
346
347void
348SectorTags::forEachBlk(std::function<void(CacheBlk &)> visitor)
349{
350 for (SectorSubBlk& blk : blks) {
351 visitor(blk);
352 }

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361 }
362 }
363 return false;
364}
365
366SectorTags *
367SectorTagsParams::create()
368{
369 return new SectorTags(this);
370}