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Diffstat (limited to 'src/mem/cache/tags/sector_tags.hh')
| -rw-r--r-- | src/mem/cache/tags/sector_tags.hh | 241 |
1 files changed, 241 insertions, 0 deletions
diff --git a/src/mem/cache/tags/sector_tags.hh b/src/mem/cache/tags/sector_tags.hh new file mode 100644 index 000000000..3fc8ae476 --- /dev/null +++ b/src/mem/cache/tags/sector_tags.hh @@ -0,0 +1,241 @@ +/* + * 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 + * Declaration of a sector set associative tag store. + */ + +#ifndef __MEM_CACHE_TAGS_SECTOR_TAGS_HH__ +#define __MEM_CACHE_TAGS_SECTOR_TAGS_HH__ + +#include <string> +#include <vector> + +#include "mem/cache/sector_blk.hh" +#include "mem/cache/tags/base.hh" +#include "mem/packet.hh" +#include "params/SectorTags.hh" + +class BaseReplacementPolicy; + +/** + * A SectorTags cache tag store. + * @sa \ref gem5MemorySystem "gem5 Memory System" + * + * The SectorTags placement policy divides the cache into s sectors of w + * consecutive sectors (ways). Each sector then consists of a number of + * sequential cache lines that may or may not be present. + */ +class SectorTags : public BaseTags +{ + protected: + /** Typedef the set type used in this tag store. */ + typedef std::vector<SectorBlk*> SetType; + + /** The associativity of the cache. */ + const unsigned assoc; + /** The allocatable associativity of the cache (alloc mask). */ + unsigned allocAssoc; + + /** Whether tags and data are accessed sequentially. */ + const bool sequentialAccess; + + /** Replacement policy */ + BaseReplacementPolicy *replacementPolicy; + + /** Number of data blocks per sector. */ + const unsigned numBlocksPerSector; + + /** The number of sectors in the cache. */ + const unsigned numSectors; + /** The number of sets in the cache. */ + const unsigned numSets; + + /** The cache blocks. */ + std::vector<SectorSubBlk> blks; + /** The cache sector blocks. */ + std::vector<SectorBlk> secBlks; + /** The cache sets. */ + std::vector<SetType> sets; + + // Organization of an address: Tag | Set # | Sector Offset # | Offset # + /** The amount to shift the address to get the sector tag. */ + const int sectorShift; + /** The amount to shift the address to get the set. */ + const int setShift; + /** The amount to shift the address to get the tag. */ + const int tagShift; + + /** Mask out all bits that aren't part of the sector tag. */ + const unsigned sectorMask; + /** Mask out all bits that aren't part of the set index. */ + const unsigned setMask; + + public: + /** Convenience typedef. */ + typedef SectorTagsParams Params; + + /** + * Construct and initialize this tag store. + */ + SectorTags(const Params *p); + + /** + * Destructor. + */ + virtual ~SectorTags() {}; + + /** + * This function updates the tags when a block is invalidated but does + * not invalidate the block itself. It also updates the replacement data. + * + * @param blk The block to invalidate. + */ + void invalidate(CacheBlk *blk) override; + + /** + * Access block and update replacement data. May not succeed, in which + * case nullptr is returned. This has all the implications of a cache + * access and should only be used as such. Returns the access latency + * as a side effect. + * + * @param addr The address to find. + * @param is_secure True if the target memory space is secure. + * @param lat The access latency. + * @return Pointer to the cache block if found. + */ + CacheBlk* accessBlock(Addr addr, bool is_secure, Cycles &lat) override; + + /** + * Find all possible block locations for insertion and replacement of + * an address. Should be called immediately before ReplacementPolicy's + * findVictim() not to break cache resizing. + * Returns sector blocks in all ways belonging to the set of the address. + * + * @param addr The addr to a find possible locations for. + * @return The possible locations. + */ + virtual const std::vector<SectorBlk*> getPossibleLocations(Addr addr) + const; + + /** + * Insert the new block into the cache and update replacement data. + * + * @param pkt Packet holding the address to update + * @param blk The block to update. + */ + void insertBlock(PacketPtr pkt, CacheBlk *blk) override; + + /** + * Finds the given address in the cache, do not update replacement data. + * i.e. This is a no-side-effect find of a block. + * + * @param addr The address to find. + * @param is_secure True if the target memory space is secure. + * @return Pointer to the cache block if found. + */ + CacheBlk* findBlock(Addr addr, bool is_secure) const override; + + /** + * Find a sector block given set and way. + * + * @param set The set of the block. + * @param way The way of the block. + * @return The block. + */ + ReplaceableEntry* findBlockBySetAndWay(int set, int way) const override; + + /** + * Find replacement victim based on address. + * + * @param addr Address to find a victim for. + * @param is_secure True if the target memory space is secure. + * @param evict_blks Cache blocks to be evicted. + * @return Cache block to be replaced. + */ + CacheBlk* findVictim(Addr addr, const bool is_secure, + std::vector<CacheBlk*>& evict_blks) const override; + + /** + * Generate the sector tag from the given address. + * + * @param addr The address to get the sector tag from. + * @return The sector tag of the address. + */ + Addr extractTag(Addr addr) const override; + + /** + * Calculate the set index from the address. + * + * @param addr The address to get the set from. + * @return The set index of the address. + */ + int extractSet(Addr addr) const; + + /** + * Calculate a block's offset in a sector from the address. + * + * @param addr The address to get the offset from. + * @return Offset of the corresponding block within its sector. + */ + int extractSectorOffset(Addr addr) const; + + /** + * Regenerate the block address from the tag and set. + * + * @param block The block. + * @return the block address. + */ + Addr regenerateBlkAddr(const CacheBlk* blk) const override; + + /** + * Visit each sub-block in the tags and apply a visitor. + * + * The visitor should be a std::function that takes a cache block. + * reference as its parameter. + * + * @param visitor Visitor to call on each block. + */ + void forEachBlk(std::function<void(CacheBlk &)> visitor) override; + + /** + * Find if any of the sub-blocks satisfies a condition. + * + * The visitor should be a std::function that takes a cache block + * reference as its parameter. The visitor will terminate the + * traversal early if the condition is satisfied. + * + * @param visitor Visitor to call on each block. + */ + bool anyBlk(std::function<bool(CacheBlk &)> visitor) override; +}; + +#endif //__MEM_CACHE_TAGS_SECTOR_TAGS_HH__ |