gem5/src/mem/ruby/system/CacheMemory.hh

/*
 * Copyright (c) 1999-2008 Mark D. Hill and David A. Wood
 * 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.
 */

/*
 * CacheMemory.h
 *
 * Description:
 *
 * $Id: CacheMemory.h,v 3.7 2004/06/18 20:15:15 beckmann Exp $
 *
 */

#ifndef CACHEMEMORY_H
#define CACHEMEMORY_H

#include "AbstractChip.hh"
#include "Global.hh"
#include "AccessPermission.hh"
#include "Address.hh"
#include "CacheRecorder.hh"
#include "CacheRequestType.hh"
#include "Vector.hh"
#include "DataBlock.hh"
#include "MachineType.hh"
#include "RubySlicc_ComponentMapping.hh"
#include "PseudoLRUPolicy.hh"
#include "LRUPolicy.hh"
#include <vector>

template<class ENTRY>
class CacheMemory {
public:

  // Constructors
  CacheMemory(AbstractChip* chip_ptr, int numSetBits, int cacheAssoc, const MachineType machType, const string& description);

  // Destructor
  ~CacheMemory();

  // Public Methods
  void printConfig(ostream& out);

  // perform a cache access and see if we hit or not.  Return true on a hit.
  bool tryCacheAccess(const Address& address, CacheRequestType type, DataBlock*& data_ptr);

  // similar to above, but doesn't require full access check
  bool testCacheAccess(const Address& address, CacheRequestType type, DataBlock*& data_ptr);

  // tests to see if an address is present in the cache
  bool isTagPresent(const Address& address) const;

  // Returns true if there is:
  //   a) a tag match on this address or there is
  //   b) an unused line in the same cache "way"
  bool cacheAvail(const Address& address) const;

  // find an unused entry and sets the tag appropriate for the address
  void allocate(const Address& address);

  // Explicitly free up this address
  void deallocate(const Address& address);

  // Returns with the physical address of the conflicting cache line
  Address cacheProbe(const Address& address) const;

  // looks an address up in the cache
  ENTRY& lookup(const Address& address);
  const ENTRY& lookup(const Address& address) const;

  // Get/Set permission of cache block
  AccessPermission getPermission(const Address& address) const;
  void changePermission(const Address& address, AccessPermission new_perm);

  // Hook for checkpointing the contents of the cache
  void recordCacheContents(CacheRecorder& tr) const;
  void setAsInstructionCache(bool is_icache) { m_is_instruction_cache = is_icache; }

  // Set this address to most recently used
  void setMRU(const Address& address);

  void getMemoryValue(const Address& addr, char* value,
                      unsigned int size_in_bytes );
  void setMemoryValue(const Address& addr, char* value,
                      unsigned int size_in_bytes );

  // Print cache contents
  void print(ostream& out) const;
  void printData(ostream& out) const;

private:
  // Private Methods

  // convert a Address to its location in the cache
  Index addressToCacheSet(const Address& address) const;

  // Given a cache tag: returns the index of the tag in a set.
  // returns -1 if the tag is not found.
  int findTagInSet(Index line, const Address& tag) const;
  int findTagInSetIgnorePermissions(Index cacheSet, const Address& tag) const;

  // Private copy constructor and assignment operator
  CacheMemory(const CacheMemory& obj);
  CacheMemory& operator=(const CacheMemory& obj);

  // Data Members (m_prefix)
  AbstractChip* m_chip_ptr;
  MachineType m_machType;
  string m_description;
  bool m_is_instruction_cache;

  // The first index is the # of cache lines.
  // The second index is the the amount associativity.
  Vector<Vector<ENTRY> > m_cache;

  AbstractReplacementPolicy *m_replacementPolicy_ptr;

  int m_cache_num_sets;
  int m_cache_num_set_bits;
  int m_cache_assoc;
};

// Output operator declaration
//ostream& operator<<(ostream& out, const CacheMemory<ENTRY>& obj);

// ******************* Definitions *******************

// Output operator definition
template<class ENTRY>
inline
ostream& operator<<(ostream& out, const CacheMemory<ENTRY>& obj)
{
  obj.print(out);
  out << flush;
  return out;
}


// ****************************************************************

template<class ENTRY>
inline
CacheMemory<ENTRY>::CacheMemory(AbstractChip* chip_ptr, int numSetBits,
                                      int cacheAssoc, const MachineType machType, const string& description)

{
  //cout << "CacheMemory constructor numThreads = " << numThreads << endl;
  m_chip_ptr = chip_ptr;
  m_machType = machType;
  m_description = MachineType_to_string(m_machType)+"_"+description;
  m_cache_num_set_bits = numSetBits;
  m_cache_num_sets = 1 << numSetBits;
  m_cache_assoc = cacheAssoc;
  m_is_instruction_cache = false;

  m_cache.setSize(m_cache_num_sets);
  if(strcmp(g_REPLACEMENT_POLICY, "PSEDUO_LRU") == 0)
    m_replacementPolicy_ptr = new PseudoLRUPolicy(m_cache_num_sets, m_cache_assoc);
  else if(strcmp(g_REPLACEMENT_POLICY, "LRU") == 0)
    m_replacementPolicy_ptr = new LRUPolicy(m_cache_num_sets, m_cache_assoc);
  else
    assert(false);
  for (int i = 0; i < m_cache_num_sets; i++) {
    m_cache[i].setSize(m_cache_assoc);
    for (int j = 0; j < m_cache_assoc; j++) {
      m_cache[i][j].m_Address.setAddress(0);
      m_cache[i][j].m_Permission = AccessPermission_NotPresent;
    }
  }


  //  cout << "Before setting trans address list size" << endl;
  //create a trans address for each SMT thread
//   m_trans_address_list.setSize(numThreads);
//   for(int i=0; i < numThreads; ++i){
//     cout << "Setting list size for list " << i << endl;
//     m_trans_address_list[i].setSize(30);
//   }
  //cout << "CacheMemory constructor finished" << endl;
}

template<class ENTRY>
inline
CacheMemory<ENTRY>::~CacheMemory()
{
  if(m_replacementPolicy_ptr != NULL)
    delete m_replacementPolicy_ptr;
}

template<class ENTRY>
inline
void CacheMemory<ENTRY>::printConfig(ostream& out)
{
  out << "Cache config: " << m_description << endl;
  out << "  cache_associativity: " << m_cache_assoc << endl;
  out << "  num_cache_sets_bits: " << m_cache_num_set_bits << endl;
  const int cache_num_sets = 1 << m_cache_num_set_bits;
  out << "  num_cache_sets: " << cache_num_sets << endl;
  out << "  cache_set_size_bytes: " << cache_num_sets * RubyConfig::dataBlockBytes() << endl;
  out << "  cache_set_size_Kbytes: "
      << double(cache_num_sets * RubyConfig::dataBlockBytes()) / (1<<10) << endl;
  out << "  cache_set_size_Mbytes: "
      << double(cache_num_sets * RubyConfig::dataBlockBytes()) / (1<<20) << endl;
  out << "  cache_size_bytes: "
      << cache_num_sets * RubyConfig::dataBlockBytes() * m_cache_assoc << endl;
  out << "  cache_size_Kbytes: "
      << double(cache_num_sets * RubyConfig::dataBlockBytes() * m_cache_assoc) / (1<<10) << endl;
  out << "  cache_size_Mbytes: "
      << double(cache_num_sets * RubyConfig::dataBlockBytes() * m_cache_assoc) / (1<<20) << endl;
}

// PRIVATE METHODS

// convert a Address to its location in the cache
template<class ENTRY>
inline
Index CacheMemory<ENTRY>::addressToCacheSet(const Address& address) const
{
  assert(address == line_address(address));
  Index temp = -1;
  switch (m_machType) {
  case MACHINETYPE_L1CACHE_ENUM:
    temp = map_address_to_L1CacheSet(address, m_cache_num_set_bits);
    break;
  case MACHINETYPE_L2CACHE_ENUM:
    temp = map_address_to_L2CacheSet(address, m_cache_num_set_bits);
    break;
  default:
    ERROR_MSG("Don't recognize m_machType");
  }
  assert(temp < m_cache_num_sets);
  assert(temp >= 0);
  return temp;
}

// Given a cache index: returns the index of the tag in a set.
// returns -1 if the tag is not found.
template<class ENTRY>
inline
int CacheMemory<ENTRY>::findTagInSet(Index cacheSet, const Address& tag) const
{
  assert(tag == line_address(tag));
  // search the set for the tags
  for (int i=0; i < m_cache_assoc; i++) {
    if ((m_cache[cacheSet][i].m_Address == tag) &&
        (m_cache[cacheSet][i].m_Permission != AccessPermission_NotPresent)) {
      return i;
    }
  }
  return -1; // Not found
}

// Given a cache index: returns the index of the tag in a set.
// returns -1 if the tag is not found.
template<class ENTRY>
inline
int CacheMemory<ENTRY>::findTagInSetIgnorePermissions(Index cacheSet, const Address& tag) const
{
  assert(tag == line_address(tag));
  // search the set for the tags
  for (int i=0; i < m_cache_assoc; i++) {
    if (m_cache[cacheSet][i].m_Address == tag)
      return i;
  }
  return -1; // Not found
}

// PUBLIC METHODS
template<class ENTRY>
inline
bool CacheMemory<ENTRY>::tryCacheAccess(const Address& address,
                                           CacheRequestType type,
                                           DataBlock*& data_ptr)
{
  assert(address == line_address(address));
  DEBUG_EXPR(CACHE_COMP, HighPrio, address);
  Index cacheSet = addressToCacheSet(address);
  int loc = findTagInSet(cacheSet, address);
  if(loc != -1){ // Do we even have a tag match?
    ENTRY& entry = m_cache[cacheSet][loc];
    m_replacementPolicy_ptr->touch(cacheSet, loc, g_eventQueue_ptr->getTime());
    data_ptr = &(entry.getDataBlk());

    if(entry.m_Permission == AccessPermission_Read_Write) {
      return true;
    }
    if ((entry.m_Permission == AccessPermission_Read_Only) &&
        (type == CacheRequestType_LD || type == CacheRequestType_IFETCH)) {
      return true;
    }
    // The line must not be accessible
  }
  data_ptr = NULL;
  return false;
}

template<class ENTRY>
inline
bool CacheMemory<ENTRY>::testCacheAccess(const Address& address,
                                           CacheRequestType type,
                                           DataBlock*& data_ptr)
{
  assert(address == line_address(address));
  DEBUG_EXPR(CACHE_COMP, HighPrio, address);
  Index cacheSet = addressToCacheSet(address);
  int loc = findTagInSet(cacheSet, address);
  if(loc != -1){ // Do we even have a tag match?
    ENTRY& entry = m_cache[cacheSet][loc];
    m_replacementPolicy_ptr->touch(cacheSet, loc, g_eventQueue_ptr->getTime());
    data_ptr = &(entry.getDataBlk());

    return (m_cache[cacheSet][loc].m_Permission != AccessPermission_NotPresent);
  }
  data_ptr = NULL;
  return false;
}

// tests to see if an address is present in the cache
template<class ENTRY>
inline
bool CacheMemory<ENTRY>::isTagPresent(const Address& address) const
{
  assert(address == line_address(address));
  Index cacheSet = addressToCacheSet(address);
  int location = findTagInSet(cacheSet, address);

  if (location == -1) {
    // We didn't find the tag
    DEBUG_EXPR(CACHE_COMP, LowPrio, address);
    DEBUG_MSG(CACHE_COMP, LowPrio, "No tag match");
    return false;
  }
  DEBUG_EXPR(CACHE_COMP, LowPrio, address);
  DEBUG_MSG(CACHE_COMP, LowPrio, "found");
  return true;
}

// Returns true if there is:
//   a) a tag match on this address or there is
//   b) an unused line in the same cache "way"
template<class ENTRY>
inline
bool CacheMemory<ENTRY>::cacheAvail(const Address& address) const
{
  assert(address == line_address(address));

  Index cacheSet = addressToCacheSet(address);

  for (int i=0; i < m_cache_assoc; i++) {
    if (m_cache[cacheSet][i].m_Address == address) {
      // Already in the cache
      return true;
    }

    if (m_cache[cacheSet][i].m_Permission == AccessPermission_NotPresent) {
      // We found an empty entry
      return true;
    }
  }
  return false;
}

template<class ENTRY>
inline
void CacheMemory<ENTRY>::allocate(const Address& address)
{
  assert(address == line_address(address));
  assert(!isTagPresent(address));
  assert(cacheAvail(address));
  DEBUG_EXPR(CACHE_COMP, HighPrio, address);

  // Find the first open slot
  Index cacheSet = addressToCacheSet(address);
  for (int i=0; i < m_cache_assoc; i++) {
    if (m_cache[cacheSet][i].m_Permission == AccessPermission_NotPresent) {
      m_cache[cacheSet][i] = ENTRY();  // Init entry
      m_cache[cacheSet][i].m_Address = address;
      m_cache[cacheSet][i].m_Permission = AccessPermission_Invalid;

      m_replacementPolicy_ptr->touch(cacheSet, i, g_eventQueue_ptr->getTime());

      return;
    }
  }
  ERROR_MSG("Allocate didn't find an available entry");
}

template<class ENTRY>
inline
void CacheMemory<ENTRY>::deallocate(const Address& address)
{
  assert(address == line_address(address));
  assert(isTagPresent(address));
  DEBUG_EXPR(CACHE_COMP, HighPrio, address);
  lookup(address).m_Permission = AccessPermission_NotPresent;
}

// Returns with the physical address of the conflicting cache line
template<class ENTRY>
inline
Address CacheMemory<ENTRY>::cacheProbe(const Address& address) const
{
  assert(address == line_address(address));
  assert(!cacheAvail(address));

  Index cacheSet = addressToCacheSet(address);
  return m_cache[cacheSet][m_replacementPolicy_ptr->getVictim(cacheSet)].m_Address;
}

// looks an address up in the cache
template<class ENTRY>
inline
ENTRY& CacheMemory<ENTRY>::lookup(const Address& address)
{
  assert(address == line_address(address));
  Index cacheSet = addressToCacheSet(address);
  int loc = findTagInSet(cacheSet, address);
  assert(loc != -1);
  return m_cache[cacheSet][loc];
}

// looks an address up in the cache
template<class ENTRY>
inline
const ENTRY& CacheMemory<ENTRY>::lookup(const Address& address) const
{
  assert(address == line_address(address));
  Index cacheSet = addressToCacheSet(address);
  int loc = findTagInSet(cacheSet, address);
  assert(loc != -1);
  return m_cache[cacheSet][loc];
}

template<class ENTRY>
inline
AccessPermission CacheMemory<ENTRY>::getPermission(const Address& address) const
{
  assert(address == line_address(address));
  return lookup(address).m_Permission;
}

template<class ENTRY>
inline
void CacheMemory<ENTRY>::changePermission(const Address& address, AccessPermission new_perm)
{
  assert(address == line_address(address));
  lookup(address).m_Permission = new_perm;
  assert(getPermission(address) == new_perm);
}

// Sets the most recently used bit for a cache block
template<class ENTRY>
inline
void CacheMemory<ENTRY>::setMRU(const Address& address)
{
  Index cacheSet;

  cacheSet = addressToCacheSet(address);
  m_replacementPolicy_ptr->touch(cacheSet,
                                 findTagInSet(cacheSet, address),
                                 g_eventQueue_ptr->getTime());
}

template<class ENTRY>
inline
void CacheMemory<ENTRY>::recordCacheContents(CacheRecorder& tr) const
{
  for (int i = 0; i < m_cache_num_sets; i++) {
    for (int j = 0; j < m_cache_assoc; j++) {
      AccessPermission perm = m_cache[i][j].m_Permission;
      CacheRequestType request_type = CacheRequestType_NULL;
      if (perm == AccessPermission_Read_Only) {
        if (m_is_instruction_cache) {
          request_type = CacheRequestType_IFETCH;
        } else {
          request_type = CacheRequestType_LD;
        }
      } else if (perm == AccessPermission_Read_Write) {
        request_type = CacheRequestType_ST;
      }

      if (request_type != CacheRequestType_NULL) {
        tr.addRecord(m_chip_ptr->getID(), m_cache[i][j].m_Address,
                     Address(0), request_type, m_replacementPolicy_ptr->getLastAccess(i, j));
      }
    }
  }
}

template<class ENTRY>
inline
void CacheMemory<ENTRY>::print(ostream& out) const
{
  out << "Cache dump: " << m_description << endl;
  for (int i = 0; i < m_cache_num_sets; i++) {
    for (int j = 0; j < m_cache_assoc; j++) {
      out << "  Index: " << i
          << " way: " << j
          << " entry: " << m_cache[i][j] << endl;
    }
  }
}

template<class ENTRY>
inline
void CacheMemory<ENTRY>::printData(ostream& out) const
{
  out << "printData() not supported" << endl;
}

template<class ENTRY>
void CacheMemory<ENTRY>::getMemoryValue(const Address& addr, char* value,
                                           unsigned int size_in_bytes ){
  ENTRY entry = lookup(line_address(addr));
  unsigned int startByte = addr.getAddress() - line_address(addr).getAddress();
  for(unsigned int i=0; i<size_in_bytes; ++i){
    value[i] = entry.m_DataBlk.getByte(i + startByte);
  }
}

template<class ENTRY>
void CacheMemory<ENTRY>::setMemoryValue(const Address& addr, char* value,
                                           unsigned int size_in_bytes ){
  ENTRY& entry = lookup(line_address(addr));
  unsigned int startByte = addr.getAddress() - line_address(addr).getAddress();
  assert(size_in_bytes > 0);
  for(unsigned int i=0; i<size_in_bytes; ++i){
    entry.m_DataBlk.setByte(i + startByte, value[i]);
  }

  entry = lookup(line_address(addr));
}

#endif //CACHEMEMORY_H