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; 9 * redistributions in binary form must reproduce the above copyright 10 * notice, this list of conditions and the following disclaimer in the 11 * documentation and/or other materials provided with the distribution; 12 * neither the name of the copyright holders nor the names of its 13 * contributors may be used to endorse or promote products derived from 14 * this software without specific prior written permission. 15 * 16 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 17 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 18 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR 19 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT 20 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 21 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT 22 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 23 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 24 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 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 * Declaration of a sector tag store. 34 */ 35 36#ifndef __MEM_CACHE_TAGS_SECTOR_TAGS_HH__ 37#define __MEM_CACHE_TAGS_SECTOR_TAGS_HH__ 38 39#include <cstdint> 40#include <string> 41#include <vector> 42 43#include "mem/cache/tags/base.hh" 44#include "mem/cache/tags/sector_blk.hh" 45#include "mem/packet.hh" 46#include "params/SectorTags.hh" 47 48class BaseReplacementPolicy; 49class ReplaceableEntry; 50 51/** 52 * A SectorTags cache tag store. 53 * @sa \ref gem5MemorySystem "gem5 Memory System" 54 * 55 * The SectorTags placement policy divides the cache into s sectors of w 56 * consecutive sectors (ways). Each sector then consists of a number of 57 * sequential cache lines that may or may not be present. 58 */ 59class SectorTags : public BaseTags 60{ 61 private: 62 /** The cache blocks. */ 63 std::vector<SectorSubBlk> blks; 64 /** The cache sector blocks. */ 65 std::vector<SectorBlk> secBlks; 66 67 protected: 68 /** The allocatable associativity of the cache (alloc mask). */ 69 unsigned allocAssoc; 70 71 /** Whether tags and data are accessed sequentially. */ 72 const bool sequentialAccess; 73 74 /** Replacement policy */ 75 BaseReplacementPolicy *replacementPolicy; 76 77 /** Number of data blocks per sector. */ 78 const unsigned numBlocksPerSector; 79 80 /** The number of sectors in the cache. */ 81 const unsigned numSectors; 82 83 // Organization of an address: 84 // Tag | Placement Location | Sector Offset # | Offset # 85 /** The amount to shift the address to get the sector tag. */ 86 const int sectorShift; 87 88 /** Mask out all bits that aren't part of the sector tag. */ 89 const unsigned sectorMask; 90 91 public: 92 /** Convenience typedef. */ 93 typedef SectorTagsParams Params; 94 95 /** 96 * Construct and initialize this tag store. 97 */ 98 SectorTags(const Params *p); 99 100 /** 101 * Destructor. 102 */ 103 virtual ~SectorTags() {}; 104 105 /** 106 * Initialize blocks as SectorBlk and SectorSubBlk instances. 107 */ 108 void tagsInit() override; 109 110 /** 111 * This function updates the tags when a block is invalidated but does 112 * not invalidate the block itself. It also updates the replacement data. 113 * 114 * @param blk The block to invalidate. 115 */ 116 void invalidate(CacheBlk *blk) override; 117 118 /** 119 * Access block and update replacement data. May not succeed, in which 120 * case nullptr is returned. This has all the implications of a cache 121 * access and should only be used as such. Returns the tag lookup latency 122 * as a side effect. 123 * 124 * @param addr The address to find. 125 * @param is_secure True if the target memory space is secure. 126 * @param lat The latency of the tag lookup. 127 * @return Pointer to the cache block if found. 128 */ 129 CacheBlk* accessBlock(Addr addr, bool is_secure, Cycles &lat) override; 130 131 /** 132 * Insert the new block into the cache and update replacement data. 133 * 134 * @param pkt Packet holding the address to update 135 * @param blk The block to update. 136 */ 137 void insertBlock(const PacketPtr pkt, CacheBlk *blk) override; 138 139 /** 140 * Finds the given address in the cache, do not update replacement data. 141 * i.e. This is a no-side-effect find of a block. 142 * 143 * @param addr The address to find. 144 * @param is_secure True if the target memory space is secure. 145 * @return Pointer to the cache block if found. 146 */ 147 CacheBlk* findBlock(Addr addr, bool is_secure) const override; 148 149 /** 150 * Find replacement victim based on address. 151 * 152 * @param addr Address to find a victim for. 153 * @param is_secure True if the target memory space is secure. 154 * @param size Size, in bits, of new block to allocate. 155 * @param evict_blks Cache blocks to be evicted. 156 * @return Cache block to be replaced. 157 */ 158 CacheBlk* findVictim(Addr addr, const bool is_secure, 159 const std::size_t size, 160 std::vector<CacheBlk*>& evict_blks) const override; 161 162 /** 163 * Calculate a block's offset in a sector from the address. 164 * 165 * @param addr The address to get the offset from. 166 * @return Offset of the corresponding block within its sector. 167 */ 168 int extractSectorOffset(Addr addr) const; 169 170 /** 171 * Regenerate the block address from the tag and location. 172 * 173 * @param block The block. 174 * @return the block address. 175 */ 176 Addr regenerateBlkAddr(const CacheBlk* blk) const override; 177 178 /** 179 * Visit each sub-block in the tags and apply a visitor. 180 * 181 * The visitor should be a std::function that takes a cache block. 182 * reference as its parameter. 183 * 184 * @param visitor Visitor to call on each block. 185 */ 186 void forEachBlk(std::function<void(CacheBlk &)> visitor) override; 187 188 /** 189 * Find if any of the sub-blocks satisfies a condition. 190 * 191 * The visitor should be a std::function that takes a cache block 192 * reference as its parameter. The visitor will terminate the 193 * traversal early if the condition is satisfied. 194 * 195 * @param visitor Visitor to call on each block. 196 */ 197 bool anyBlk(std::function<bool(CacheBlk &)> visitor) override; 198}; 199 200#endif //__MEM_CACHE_TAGS_SECTOR_TAGS_HH__ 201