text: /*
   * Copyright (c) 2012-2014,2016-2019 ARM Limited
   * All rights reserved.
   *
   * The license below extends only to copyright in the software and shall
   * not be construed as granting a license to any other intellectual
   * property including but not limited to intellectual property relating
   * to a hardware implementation of the functionality of the software
   * licensed hereunder.  You may use the software subject to the license
   * terms below provided that you ensure that this notice is replicated
   * unmodified and in its entirety in all distributions of the software,
   * modified or unmodified, in source code or in binary form.
   *
   * Copyright (c) 2003-2005 The Regents of The University of Michigan
   * 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.
   */
  
  /**
   * @file
   * Declaration of a common base class for cache tagstore objects.
   */
  
  #ifndef __MEM_CACHE_TAGS_BASE_HH__
  #define __MEM_CACHE_TAGS_BASE_HH__
  
  #include <cassert>
  #include <cstdint>
  #include <functional>
  #include <string>
  
  #include "base/callback.hh"
  #include "base/logging.hh"
  #include "base/statistics.hh"
  #include "base/types.hh"
  #include "mem/cache/cache_blk.hh"
  #include "mem/packet.hh"
  #include "params/BaseTags.hh"
  #include "sim/clocked_object.hh"
  
  class System;
  class IndexingPolicy;
  class ReplaceableEntry;
  
  /**
   * A common base class of Cache tagstore objects.
   */
  class BaseTags : public ClockedObject
  {
    protected:
      /** The block size of the cache. */
      const unsigned blkSize;
      /** Mask out all bits that aren't part of the block offset. */
      const Addr blkMask;
      /** The size of the cache. */
      unsigned size;
      /** The tag lookup latency of the cache. */
      const Cycles lookupLatency;
  
      /** System we are currently operating in. */
      System *system;
  
      /** Indexing policy */
      BaseIndexingPolicy *indexingPolicy;
  
      /**
       * The number of tags that need to be touched to meet the warmup
       * percentage.
       */
      const unsigned warmupBound;
      /** Marked true when the cache is warmed up. */
      bool warmedUp;
  
      /** the number of blocks in the cache */
      unsigned numBlocks;
  
      bool didSizeIncrease;
  
      /** The data blocks, 1 per cache block. */
      std::unique_ptr<uint8_t[]> dataBlks;
  
      /**
       * TODO: It would be good if these stats were acquired after warmup.
       */
      struct BaseTagStats : public Stats::Group
      {
          BaseTagStats(BaseTags &tags);
  
          void regStats() override;
          void preDumpStats() override;
  
          BaseTags &tags;
  
          /** Per cycle average of the number of tags that hold valid data. */
          Stats::Average tagsInUse;
  
          /** The total number of references to a block before it is replaced. */
          Stats::Scalar totalRefs;
  
          /**
           * The number of reference counts sampled. This is different
           * from replacements because we sample all the valid blocks
           * when the simulator exits.
           */
          Stats::Scalar sampledRefs;
  
          /**
           * Average number of references to a block before is was replaced.
           * @todo This should change to an average stat once we have them.
           */
          Stats::Formula avgRefs;
  
          /** The cycle that the warmup percentage was hit. 0 on failure. */
          Stats::Scalar warmupCycle;
  
          /** Average occupancy of each requestor using the cache */
          Stats::AverageVector occupancies;
  
          /** Average occ % of each requestor using the cache */
          Stats::Formula avgOccs;
  
          /** Occupancy of each context/cpu using the cache */
          Stats::Vector occupanciesTaskId;
  
          /** Occupancy of each context/cpu using the cache */
          Stats::Vector2d ageTaskId;
  
          /** Occ % of each context/cpu using the cache */
          Stats::Formula percentOccsTaskId;
  
          /** Number of tags consulted over all accesses. */
          Stats::Scalar tagAccesses;
          /** Number of data blocks consulted over all accesses. */
          Stats::Scalar dataAccesses;
      } stats;
  
    public:
      typedef BaseTagsParams Params;
      BaseTags(const Params *p);
  
      /**
       * Destructor.
       */
      virtual ~BaseTags() {}
  
      /**
       * Initialize blocks. Must be overriden by every subclass that uses
       * a block type different from its parent's, as the current Python
       * code generation does not allow templates.
       */
      virtual void tagsInit() = 0;
  
      /**
       * Average in the reference count for valid blocks when the simulation
       * exits.
       */
      void cleanupRefs();
  
      /**
       * Computes stats just prior to dump event
       */
      void computeStats();
  
      /**
       * Print all tags used
       */
      std::string print();
  
      /**
       * Finds the block in the cache without touching it.
       *
       * @param addr The address to look for.
       * @param is_secure True if the target memory space is secure.
       * @return Pointer to the cache block.
       */
      virtual CacheBlk *findBlock(Addr addr, bool is_secure) const;
  
      /**
       * Find a block given set and way.
       *
       * @param set The set of the block.
       * @param way The way of the block.
       * @return The block.
       */
      virtual ReplaceableEntry* findBlockBySetAndWay(int set, int way) const;
  
      /**
       * Align an address to the block size.
       * @param addr the address to align.
       * @return The block address.
       */
      Addr blkAlign(Addr addr) const
      {
          return addr & ~blkMask;
      }
  
      /**
       * Calculate the block offset of an address.
       * @param addr the address to get the offset of.
       * @return the block offset.
       */
      int extractBlkOffset(Addr addr) const
      {
          return (addr & blkMask);
      }
  
      /**
       * Limit the allocation for the cache ways.
       * @param ways The maximum number of ways available for replacement.
       */
      virtual void setWayAllocationMax(int ways)
      {
          panic("This tag class does not implement way allocation limit!\n");
      }
  
      /**
       * Get the way allocation mask limit.
       * @return The maximum number of ways available for replacement.
       */
      virtual int getWayAllocationMax() const
      {
          panic("This tag class does not implement way allocation limit!\n");
          return -1;
      }
  
      /**
       * This function updates the tags when a block is invalidated
       *
       * @param blk A valid block to invalidate.
       */
      virtual void invalidate(CacheBlk *blk)
      {
          assert(blk);
          assert(blk->isValid());
  
          stats.occupancies[blk->srcMasterId]--;
          stats.totalRefs += blk->refCount;
          stats.sampledRefs++;
  
          blk->invalidate();
      }
  
      /**
       * Double the size of the cache by increasing ways.
       */
  
       void* ownerCache; //pointer to a BaseCache object
       void setOwnerCache(void* cache);
       
       virtual void doubleSize()
       {}
  
       virtual void halfSize()
       {}
  
      /**
       * Find replacement victim based on address. If the address requires
       * blocks to be evicted, their locations are listed for eviction. If a
       * conventional cache is being used, the list only contains the victim.
       * However, if using sector or compressed caches, the victim is one of
       * the blocks to be evicted, but its location is the only one that will
       * be assigned to the newly allocated block associated to this address.
       * @sa insertBlock
       *
       * @param addr Address to find a victim for.
       * @param is_secure True if the target memory space is secure.
       * @param size Size, in bits, of new block to allocate.
       * @param evict_blks Cache blocks to be evicted.
       * @return Cache block to be replaced.
       */
      virtual CacheBlk* findVictim(Addr addr, const bool is_secure,
                                   const std::size_t size,
                                   std::vector<CacheBlk*>& evict_blks) = 0;
  
      /**
       * 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 tag lookup 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 latency of the tag lookup.
       * @return Pointer to the cache block if found.
       */
      virtual CacheBlk* accessBlock(Addr addr, bool is_secure, Cycles &lat) = 0;
  
      /**
       * Generate the tag from the given address.
       *
       * @param addr The address to get the tag from.
       * @return The tag of the address.
       */
      virtual Addr extractTag(const Addr addr) const;
  
      /**
       * Insert the new block into the cache and update stats.
       *
       * @param pkt Packet holding the address to update
       * @param blk The block to update.
       */
      virtual void insertBlock(const PacketPtr pkt, CacheBlk *blk);
  
      /**
       * Regenerate the block address.
       *
       * @param block The block.
       * @return the block address.
       */
      virtual Addr regenerateBlkAddr(const CacheBlk* blk) const = 0;
  
      /**
       * Visit each 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.
       */
      virtual void forEachBlk(std::function<void(CacheBlk &)> visitor) = 0;
  
      /**
       * Find if any of the 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.
       */
      virtual bool anyBlk(std::function<bool(CacheBlk &)> visitor) = 0;
  
    private:
      /**
       * Update the reference stats using data from the input block
       *
       * @param blk The input block
       */
      void cleanupRefsVisitor(CacheBlk &blk);
  
      /**
       * Update the occupancy and age stats using data from the input block
       *
       * @param blk The input block
       */
      void computeStatsVisitor(CacheBlk &blk);
  };
  
  class BaseTagsCallback : public Callback
  {
      BaseTags *tags;
    public:
      BaseTagsCallback(BaseTags *t) : tags(t) {}
      virtual void process() { tags->cleanupRefs(); };
  };
  
  #endif //__MEM_CACHE_TAGS_BASE_HH__
  