src/mem/abstract_mem.hh

   1 /*
   2  * Copyright (c) 2012 ARM Limited
   3  * All rights reserved
   4  *
   5  * The license below extends only to copyright in the software and shall
   6  * not be construed as granting a license to any other intellectual
   7  * property including but not limited to intellectual property relating
   8  * to a hardware implementation of the functionality of the software
   9  * licensed hereunder.  You may use the software subject to the license
  10  * terms below provided that you ensure that this notice is replicated
  11  * unmodified and in its entirety in all distributions of the software,
  12  * modified or unmodified, in source code or in binary form.
  13  *
  14  * Copyright (c) 2001-2005 The Regents of The University of Michigan
  15  * All rights reserved.
  16  *
  17  * Redistribution and use in source and binary forms, with or without
  18  * modification, are permitted provided that the following conditions are
  19  * met: redistributions of source code must retain the above copyright
  20  * notice, this list of conditions and the following disclaimer;
  21  * redistributions in binary form must reproduce the above copyright
  22  * notice, this list of conditions and the following disclaimer in the
  23  * documentation and/or other materials provided with the distribution;
  24  * neither the name of the copyright holders nor the names of its
  25  * contributors may be used to endorse or promote products derived from
  26  * this software without specific prior written permission.
  27  *
  28  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  29  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  30  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
  31  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
  32  * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  33  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
  34  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  35  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  36  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  37  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  38  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  39  *
  40  * Authors: Ron Dreslinski
  41  *          Andreas Hansson
  42  */
  43
  44 /**
  45  * @file
  46  * AbstractMemory declaration
  47  */
  48
  49 #ifndef __ABSTRACT_MEMORY_HH__
  50 #define __ABSTRACT_MEMORY_HH__
  51
  52 #include "mem/mem_object.hh"
  53 #include "params/AbstractMemory.hh"
  54 #include "sim/stats.hh"
  55
  56
  57 class System;
  58
  59 /**
  60  * Locked address class that represents a physical address and a
  61  * context id.
  62  */
  63 class LockedAddr {
  64
  65   private:
  66
  67     // on alpha, minimum LL/SC granularity is 16 bytes, so lower
  68     // bits need to masked off.
  69     static const Addr Addr_Mask = 0xf;
  70
  71   public:
  72
  73     // locked address
  74     Addr addr;
  75
  76     // locking hw context
  77     const ContextID contextId;
  78
  79     static Addr mask(Addr paddr) { return (paddr & ~Addr_Mask); }
  80
  81     // check for matching execution context
  82     bool matchesContext(Request *req) const
  83     {
  84         return (contextId == req->contextId());
  85     }
  86
  87     LockedAddr(Request *req) : addr(mask(req->getPaddr())),
  88                                contextId(req->contextId())
  89     {}
  90
  91     // constructor for unserialization use
  92     LockedAddr(Addr _addr, int _cid) : addr(_addr), contextId(_cid)
  93     {}
  94 };
  95
  96 /**
  97  * An abstract memory represents a contiguous block of physical
  98  * memory, with an associated address range, and also provides basic
  99  * functionality for reading and writing this memory without any
 100  * timing information. It is a MemObject since any subclass must have
 101  * at least one slave port.
 102  */
 103 class AbstractMemory : public MemObject
 104 {
 105   protected:
 106
 107     // Address range of this memory
 108     AddrRange range;
 109
 110     // Pointer to host memory used to implement this memory
 111     uint8_t* pmemAddr;
 112
 113     // Enable specific memories to be reported to the configuration table
 114     const bool confTableReported;
 115
 116     // Should the memory appear in the global address map
 117     const bool inAddrMap;
 118
 119     // Should KVM map this memory for the guest
 120     const bool kvmMap;
 121
 122     std::list<LockedAddr> lockedAddrList;
 123
 124     // helper function for checkLockedAddrs(): we really want to
 125     // inline a quick check for an empty locked addr list (hopefully
 126     // the common case), and do the full list search (if necessary) in
 127     // this out-of-line function
 128     bool checkLockedAddrList(PacketPtr pkt);
 129
 130     // Record the address of a load-locked operation so that we can
 131     // clear the execution context's lock flag if a matching store is
 132     // performed
 133     void trackLoadLocked(PacketPtr pkt);
 134
 135     // Compare a store address with any locked addresses so we can
 136     // clear the lock flag appropriately.  Return value set to 'false'
 137     // if store operation should be suppressed (because it was a
 138     // conditional store and the address was no longer locked by the
 139     // requesting execution context), 'true' otherwise.  Note that
 140     // this method must be called on *all* stores since even
 141     // non-conditional stores must clear any matching lock addresses.
 142     bool writeOK(PacketPtr pkt) {
 143         Request *req = pkt->req;
 144         if (lockedAddrList.empty()) {
 145             // no locked addrs: nothing to check, store_conditional fails
 146             bool isLLSC = pkt->isLLSC();
 147             if (isLLSC) {
 148                 req->setExtraData(0);
 149             }
 150             return !isLLSC; // only do write if not an sc
 151         } else {
 152             // iterate over list...
 153             return checkLockedAddrList(pkt);
 154         }
 155     }
 156
 157     /** Number of total bytes read from this memory */
 158     Stats::Vector bytesRead;
 159     /** Number of instruction bytes read from this memory */
 160     Stats::Vector bytesInstRead;
 161     /** Number of bytes written to this memory */
 162     Stats::Vector bytesWritten;
 163     /** Number of read requests */
 164     Stats::Vector numReads;
 165     /** Number of write requests */
 166     Stats::Vector numWrites;
 167     /** Number of other requests */
 168     Stats::Vector numOther;
 169     /** Read bandwidth from this memory */
 170     Stats::Formula bwRead;
 171     /** Read bandwidth from this memory */
 172     Stats::Formula bwInstRead;
 173     /** Write bandwidth from this memory */
 174     Stats::Formula bwWrite;
 175     /** Total bandwidth from this memory */
 176     Stats::Formula bwTotal;
 177
 178     /** Pointor to the System object.
 179      * This is used for getting the number of masters in the system which is
 180      * needed when registering stats
 181      */
 182     System *_system;
 183
 184
 185   private:
 186
 187     // Prevent copying
 188     AbstractMemory(const AbstractMemory&);
 189
 190     // Prevent assignment
 191     AbstractMemory& operator=(const AbstractMemory&);
 192
 193   public:
 194
 195     typedef AbstractMemoryParams Params;
 196
 197     AbstractMemory(const Params* p);
 198     virtual ~AbstractMemory() {}
 199
 200     /**
 201      * Initialise this memory.
 202      */
 203     void init() override;
 204
 205     /**
 206      * See if this is a null memory that should never store data and
 207      * always return zero.
 208      *
 209      * @return true if null
 210      */
 211     bool isNull() const { return params()->null; }
 212
 213     /**
 214      * Set the host memory backing store to be used by this memory
 215      * controller.
 216      *
 217      * @param pmem_addr Pointer to a segment of host memory
 218      */
 219     void setBackingStore(uint8_t* pmem_addr);
 220
 221     /**
 222      * Get the list of locked addresses to allow checkpointing.
 223      */
 224     const std::list<LockedAddr>& getLockedAddrList() const
 225     { return lockedAddrList; }
 226
 227     /**
 228      * Add a locked address to allow for checkpointing.
 229      */
 230     void addLockedAddr(LockedAddr addr) { lockedAddrList.push_back(addr); }
 231
 232     /** read the system pointer
 233      * Implemented for completeness with the setter
 234      * @return pointer to the system object */
 235     System* system() const { return _system; }
 236
 237     /** Set the system pointer on this memory
 238      * This can't be done via a python parameter because the system needs
 239      * pointers to all the memories and the reverse would create a cycle in the
 240      * object graph. An init() this is set.
 241      * @param sys system pointer to set
 242      */
 243     void system(System *sys) { _system = sys; }
 244
 245     const Params *
 246     params() const
 247     {
 248         return dynamic_cast<const Params *>(_params);
 249     }
 250
 251     /**
 252      * Get the address range
 253      *
 254      * @return a single contigous address range
 255      */
 256     AddrRange getAddrRange() const;
 257
 258     /**
 259      * Get the memory size.
 260      *
 261      * @return the size of the memory
 262      */
 263     uint64_t size() const { return range.size(); }
 264
 265     /**
 266      * Get the start address.
 267      *
 268      * @return the start address of the memory
 269      */
 270     Addr start() const { return range.start(); }
 271
 272     /**
 273      *  Should this memory be passed to the kernel and part of the OS
 274      *  physical memory layout.
 275      *
 276      * @return if this memory is reported
 277      */
 278     bool isConfReported() const { return confTableReported; }
 279
 280     /**
 281      * Some memories are used as shadow memories or should for other
 282      * reasons not be part of the global address map.
 283      *
 284      * @return if this memory is part of the address map
 285      */
 286     bool isInAddrMap() const { return inAddrMap; }
 287
 288     /**
 289      * When shadow memories are in use, KVM may want to make one or the other,
 290      * but cannot map both into the guest address space.
 291      *
 292      * @return if this memory should be mapped into the KVM guest address space
 293      */
 294     bool isKvmMap() const { return kvmMap; }
 295
 296     /**
 297      * Perform an untimed memory access and update all the state
 298      * (e.g. locked addresses) and statistics accordingly. The packet
 299      * is turned into a response if required.
 300      *
 301      * @param pkt Packet performing the access
 302      */
 303     void access(PacketPtr pkt);
 304
 305     /**
 306      * Perform an untimed memory read or write without changing
 307      * anything but the memory itself. No stats are affected by this
 308      * access. In addition to normal accesses this also facilitates
 309      * print requests.
 310      *
 311      * @param pkt Packet performing the access
 312      */
 313     void functionalAccess(PacketPtr pkt);
 314
 315     /**
 316      * Register Statistics
 317      */
 318     void regStats() override;
 319
 320 };
 321
 322 #endif //__ABSTRACT_MEMORY_HH__