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+/*
+ * Copyright (c) 2018 Inria
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met: redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer;
+ * redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in the
+ * documentation and/or other materials provided with the distribution;
+ * neither the name of the copyright holders nor the names of its
+ * contributors may be used to endorse or promote products derived from
+ * this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ * Authors: Daniel Carvalho
+ */
+
+/**
+ * @file
+ * Definitions of a base set associative sector tag store.
+ */
+
+#include "mem/cache/tags/sector_tags.hh"
+
+#include <cassert>
+#include <memory>
+#include <string>
+
+#include "base/intmath.hh"
+#include "base/logging.hh"
+#include "base/types.hh"
+#include "debug/CacheRepl.hh"
+#include "mem/cache/base.hh"
+#include "mem/cache/replacement_policies/base.hh"
+
+SectorTags::SectorTags(const SectorTagsParams *p)
+ : BaseTags(p), assoc(p->assoc), allocAssoc(p->assoc),
+ sequentialAccess(p->sequential_access),
+ replacementPolicy(p->replacement_policy),
+ numBlocksPerSector(p->num_blocks_per_sector),
+ numSectors(numBlocks / p->num_blocks_per_sector),
+ numSets(numSectors / p->assoc),
+ blks(numBlocks), secBlks(numSectors), sets(numSets),
+ sectorShift(floorLog2(blkSize)),
+ setShift(sectorShift + floorLog2(numBlocksPerSector)),
+ tagShift(setShift + floorLog2(numSets)),
+ sectorMask(numBlocksPerSector - 1), setMask(numSets - 1)
+{
+ // Check parameters
+ fatal_if(blkSize < 4 || !isPowerOf2(blkSize),
+ "Block size must be at least 4 and a power of 2");
+ fatal_if(!isPowerOf2(numSets),
+ "# of sets must be non-zero and a power of 2");
+ fatal_if(!isPowerOf2(numBlocksPerSector),
+ "# of blocks per sector must be non-zero and a power of 2");
+ fatal_if(assoc <= 0, "associativity must be greater than zero");
+
+ // Initialize all sets
+ unsigned sec_blk_index = 0; // index into sector blks array
+ unsigned blk_index = 0; // index into blks array
+ for (unsigned i = 0; i < numSets; ++i) {
+ sets[i].resize(assoc);
+
+ // Initialize all sectors in this set
+ for (unsigned j = 0; j < assoc; ++j) {
+ // Select block within the set to be linked
+ SectorBlk*& sec_blk = sets[i][j];
+
+ // Locate next cache sector
+ sec_blk = &secBlks[sec_blk_index];
+
+ // Associate a replacement data entry to the sector
+ sec_blk->replacementData = replacementPolicy->instantiateEntry();
+
+ // Initialize all blocks in this sector
+ sec_blk->blks.resize(numBlocksPerSector);
+ for (unsigned k = 0; k < numBlocksPerSector; ++k){
+ // Select block within the set to be linked
+ SectorSubBlk*& blk = sec_blk->blks[k];
+
+ // Locate next cache block
+ blk = &blks[blk_index];
+
+ // Associate a data chunk to the block
+ blk->data = &dataBlks[blkSize*blk_index];
+
+ // Associate sector block to this block
+ blk->setSectorBlock(sec_blk);
+
+ // Associate the sector replacement data to this block
+ blk->replacementData = sec_blk->replacementData;
+
+ // Set its set, way and sector offset
+ blk->set = i;
+ blk->way = j;
+ blk->setSectorOffset(k);
+
+ // Update block index
+ ++blk_index;
+ }
+
+ // Update sector block index
+ ++sec_blk_index;
+ }
+ }
+}
+
+void
+SectorTags::invalidate(CacheBlk *blk)
+{
+ BaseTags::invalidate(blk);
+
+ // Get block's sector
+ SectorSubBlk* sub_blk = static_cast<SectorSubBlk*>(blk);
+ const SectorBlk* sector_blk = sub_blk->getSectorBlock();
+
+ // When a block in a sector is invalidated, it does not make the tag
+ // invalid automatically, as there might be other blocks in the sector
+ // using it. The tag is invalidated only when there is a single block
+ // in the sector.
+ if (!sector_blk->isValid()) {
+ // Decrease the number of tags in use
+ tagsInUse--;
+
+ // Invalidate replacement data, as we're invalidating the sector
+ replacementPolicy->invalidate(sector_blk->replacementData);
+ }
+}
+
+CacheBlk*
+SectorTags::accessBlock(Addr addr, bool is_secure, Cycles &lat)
+{
+ CacheBlk *blk = findBlock(addr, is_secure);
+
+ // Access all tags in parallel, hence one in each way. The data side
+ // either accesses all blocks in parallel, or one block sequentially on
+ // a hit. Sequential access with a miss doesn't access data.
+ tagAccesses += allocAssoc;
+ if (sequentialAccess) {
+ if (blk != nullptr) {
+ dataAccesses += 1;
+ }
+ } else {
+ dataAccesses += allocAssoc*numBlocksPerSector;
+ }
+
+ if (blk != nullptr) {
+ // If a cache hit
+ lat = accessLatency;
+ // Check if the block to be accessed is available. If not,
+ // apply the accessLatency on top of block->whenReady.
+ if (blk->whenReady > curTick() &&
+ cache->ticksToCycles(blk->whenReady - curTick()) >
+ accessLatency) {
+ lat = cache->ticksToCycles(blk->whenReady - curTick()) +
+ accessLatency;
+ }
+
+ // Update number of references to accessed block
+ blk->refCount++;
+
+ // Get block's sector
+ SectorSubBlk* sub_blk = static_cast<SectorSubBlk*>(blk);
+ const SectorBlk* sector_blk = sub_blk->getSectorBlock();
+
+ // Update replacement data of accessed block, which is shared with
+ // the whole sector it belongs to
+ replacementPolicy->touch(sector_blk->replacementData);
+ } else {
+ // If a cache miss
+ lat = lookupLatency;
+ }
+
+ return blk;
+}
+
+const std::vector<SectorBlk*>
+SectorTags::getPossibleLocations(Addr addr) const
+{
+ return sets[extractSet(addr)];
+}
+
+void
+SectorTags::insertBlock(PacketPtr pkt, CacheBlk *blk)
+{
+ // Insert block
+ BaseTags::insertBlock(pkt, blk);
+
+ // Get block's sector
+ SectorSubBlk* sub_blk = static_cast<SectorSubBlk*>(blk);
+ const SectorBlk* sector_blk = sub_blk->getSectorBlock();
+
+ // When a block is inserted, the tag is only a newly used tag if the
+ // sector was not previously present in the cache.
+ // This assumes BaseTags::insertBlock does not set the valid bit.
+ if (sector_blk->isValid()) {
+ // An existing entry's replacement data is just updated
+ replacementPolicy->touch(sector_blk->replacementData);
+ } else {
+ // Increment tag counter
+ tagsInUse++;
+
+ // A new entry resets the replacement data
+ replacementPolicy->reset(sector_blk->replacementData);
+ }
+}
+
+CacheBlk*
+SectorTags::findBlock(Addr addr, bool is_secure) const
+{
+ // Extract sector tag
+ const Addr tag = extractTag(addr);
+
+ // The address can only be mapped to a specific location of a sector
+ // due to sectors being composed of contiguous-address entries
+ const Addr offset = extractSectorOffset(addr);
+
+ // Find all possible sector locations for the given address
+ const std::vector<SectorBlk*> locations = getPossibleLocations(addr);
+
+ // Search for block
+ for (const auto& sector : locations) {
+ auto blk = sector->blks[offset];
+ if (blk->getTag() == tag && blk->isValid() &&
+ blk->isSecure() == is_secure) {
+ return blk;
+ }
+ }
+
+ // Did not find block
+ return nullptr;
+}
+
+ReplaceableEntry*
+SectorTags::findBlockBySetAndWay(int set, int way) const
+{
+ return sets[set][way];
+}
+
+CacheBlk*
+SectorTags::findVictim(Addr addr, const bool is_secure,
+ std::vector<CacheBlk*>& evict_blks) const
+{
+ // Get all possible locations of this sector
+ const std::vector<SectorBlk*> sector_locations =
+ getPossibleLocations(addr);
+
+ // Check if the sector this address belongs to has been allocated
+ Addr tag = extractTag(addr);
+ SectorBlk* victim_sector = nullptr;
+ for (const auto& sector : sector_locations){
+ if ((tag == sector->getTag()) && sector->isValid() &&
+ (is_secure == sector->isSecure())){
+ victim_sector = sector;
+ break;
+ }
+ }
+
+ // If the sector is not present
+ if (victim_sector == nullptr){
+ // Choose replacement victim from replacement candidates
+ victim_sector = static_cast<SectorBlk*>(replacementPolicy->getVictim(
+ std::vector<ReplaceableEntry*>(
+ sector_locations.begin(), sector_locations.end())));
+ }
+
+ // Get the location of the victim block within the sector
+ CacheBlk* victim = victim_sector->blks[extractSectorOffset(addr)];
+
+ // Get evicted blocks. Blocks are only evicted if the sectors mismatch and
+ // the currently existing sector is valid.
+ if ((tag == victim_sector->getTag()) &&
+ (is_secure == victim_sector->isSecure())){
+ // It would be a hit if victim was valid, and upgrades do not call
+ // findVictim, so it cannot happen
+ assert(!victim->isValid());
+ } else {
+ // The whole sector must be evicted to make room for the new sector
+ for (const auto& blk : victim_sector->blks){
+ evict_blks.push_back(blk);
+ }
+ }
+
+ SectorSubBlk* victim_cast = static_cast<SectorSubBlk*>(victim);
+ DPRINTF(CacheRepl, "set %x, way %x, sector offset %x: %s\n",
+ "selecting blk for replacement\n", victim->set, victim->way,
+ victim_cast->getSectorOffset());
+
+ return victim;
+}
+
+Addr
+SectorTags::extractTag(Addr addr) const
+{
+ return addr >> tagShift;
+}
+
+int
+SectorTags::extractSet(Addr addr) const
+{
+ return (addr >> setShift) & setMask;
+}
+
+int
+SectorTags::extractSectorOffset(Addr addr) const
+{
+ return (addr >> sectorShift) & sectorMask;
+}
+
+Addr
+SectorTags::regenerateBlkAddr(const CacheBlk* blk) const
+{
+ const SectorSubBlk* blk_cast = static_cast<const SectorSubBlk*>(blk);
+ return ((blk_cast->getTag() << tagShift) | ((Addr)blk->set << setShift) |
+ ((Addr)blk_cast->getSectorOffset() << sectorShift));
+}
+
+void
+SectorTags::forEachBlk(std::function<void(CacheBlk &)> visitor)
+{
+ for (SectorSubBlk& blk : blks) {
+ visitor(blk);
+ }
+}
+
+bool
+SectorTags::anyBlk(std::function<bool(CacheBlk &)> visitor)
+{
+ for (SectorSubBlk& blk : blks) {
+ if (visitor(blk)) {
+ return true;
+ }
+ }
+ return false;
+}
+
+SectorTags *
+SectorTagsParams::create()
+{
+ return new SectorTags(this);
+}
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