src/mem/packet.hh

   1 /*
   2  * Copyright (c) 2006 The Regents of The University of Michigan
   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: Ron Dreslinski
  29  *          Steve Reinhardt
  30  *          Ali Saidi
  31  */
  32
  33 /**
  34  * @file
  35  * Declaration of the Packet class.
  36  */
  37
  38 #ifndef __MEM_PACKET_HH__
  39 #define __MEM_PACKET_HH__
  40
  41 #include "mem/request.hh"
  42 #include "arch/isa_traits.hh"
  43 #include "sim/root.hh"
  44 #include <list>
  45
  46 struct Packet;
  47 typedef Packet* PacketPtr;
  48 typedef uint8_t* PacketDataPtr;
  49 typedef std::list<PacketPtr> PacketList;
  50
  51 //Coherence Flags
  52 #define NACKED_LINE 1 << 0
  53 #define SATISFIED 1 << 1
  54 #define SHARED_LINE 1 << 2
  55 #define CACHE_LINE_FILL 1 << 3
  56 #define COMPRESSED 1 << 4
  57 #define NO_ALLOCATE 1 << 5
  58
  59 //For statistics we need max number of commands, hard code it at
  60 //20 for now.  @todo fix later
  61 #define NUM_MEM_CMDS 1 << 9
  62
  63 /**
  64  * A Packet is used to encapsulate a transfer between two objects in
  65  * the memory system (e.g., the L1 and L2 cache).  (In contrast, a
  66  * single Request travels all the way from the requester to the
  67  * ultimate destination and back, possibly being conveyed by several
  68  * different Packets along the way.)
  69  */
  70 class Packet
  71 {
  72   public:
  73     /** Temporary FLAGS field until cache gets working, this should be in coherence/sender state. */
  74     uint64_t flags;
  75
  76   private:
  77    /** A pointer to the data being transfered.  It can be differnt
  78     *    sizes at each level of the heirarchy so it belongs in the
  79     *    packet, not request. This may or may not be populated when a
  80     *    responder recieves the packet. If not populated it memory
  81     *    should be allocated.
  82     */
  83     PacketDataPtr data;
  84
  85     /** Is the data pointer set to a value that shouldn't be freed
  86      *   when the packet is destroyed? */
  87     bool staticData;
  88     /** The data pointer points to a value that should be freed when
  89      *   the packet is destroyed. */
  90     bool dynamicData;
  91     /** the data pointer points to an array (thus delete [] ) needs to
  92      *   be called on it rather than simply delete.*/
  93     bool arrayData;
  94
  95
  96     /** The address of the request.  This address could be virtual or
  97      *   physical, depending on the system configuration. */
  98     Addr addr;
  99
 100      /** The size of the request or transfer. */
 101     int size;
 102
 103     /** Device address (e.g., bus ID) of the source of the
 104      *   transaction. The source is not responsible for setting this
 105      *   field; it is set implicitly by the interconnect when the
 106      *   packet * is first sent.  */
 107     short src;
 108
 109     /** Device address (e.g., bus ID) of the destination of the
 110      *   transaction. The special value Broadcast indicates that the
 111      *   packet should be routed based on its address. This field is
 112      *   initialized in the constructor and is thus always valid
 113      *   (unlike * addr, size, and src). */
 114     short dest;
 115
 116     /** Are the 'addr' and 'size' fields valid? */
 117     bool addrSizeValid;
 118     /** Is the 'src' field valid? */
 119     bool srcValid;
 120
 121
 122   public:
 123
 124     /** Used to calculate latencies for each packet.*/
 125     Tick time;
 126
 127     /** The special destination address indicating that the packet
 128      *   should be routed based on its address. */
 129     static const short Broadcast = -1;
 130
 131     /** A pointer to the original request. */
 132     RequestPtr req;
 133
 134     /** A virtual base opaque structure used to hold coherence-related
 135      *    state.  A specific subclass would be derived from this to
 136      *    carry state specific to a particular coherence protocol.  */
 137     class CoherenceState {
 138       public:
 139         virtual ~CoherenceState() {}
 140     };
 141
 142     /** This packet's coherence state.  Caches should use
 143      *   dynamic_cast<> to cast to the state appropriate for the
 144      *   system's coherence protocol.  */
 145     CoherenceState *coherence;
 146
 147     /** A virtual base opaque structure used to hold state associated
 148      *    with the packet but specific to the sending device (e.g., an
 149      *    MSHR).  A pointer to this state is returned in the packet's
 150      *    response so that the sender can quickly look up the state
 151      *    needed to process it.  A specific subclass would be derived
 152      *    from this to carry state specific to a particular sending
 153      *    device.  */
 154     class SenderState {
 155       public:
 156         virtual ~SenderState() {}
 157     };
 158
 159     /** This packet's sender state.  Devices should use dynamic_cast<>
 160      *   to cast to the state appropriate to the sender. */
 161     SenderState *senderState;
 162
 163   private:
 164     /** List of command attributes. */
 165     enum CommandAttribute
 166     {
 167         IsRead          = 1 << 0,
 168         IsWrite         = 1 << 1,
 169         IsPrefetch      = 1 << 2,
 170         IsInvalidate    = 1 << 3,
 171         IsRequest       = 1 << 4,
 172         IsResponse      = 1 << 5,
 173         NeedsResponse   = 1 << 6,
 174         IsSWPrefetch    = 1 << 7,
 175         IsHWPrefetch    = 1 << 8
 176     };
 177
 178   public:
 179     /** List of all commands associated with a packet. */
 180     enum Command
 181     {
 182         InvalidCmd      = 0,
 183         ReadReq         = IsRead  | IsRequest | NeedsResponse,
 184         WriteReq        = IsWrite | IsRequest | NeedsResponse,
 185         WriteReqNoAck   = IsWrite | IsRequest,
 186         ReadResp        = IsRead  | IsResponse | NeedsResponse,
 187         WriteResp       = IsWrite | IsResponse | NeedsResponse,
 188         Writeback       = IsWrite | IsRequest,
 189         SoftPFReq       = IsRead  | IsRequest | IsSWPrefetch | NeedsResponse,
 190         HardPFReq       = IsRead  | IsRequest | IsHWPrefetch | NeedsResponse,
 191         SoftPFResp      = IsRead  | IsResponse | IsSWPrefetch | NeedsResponse,
 192         HardPFResp      = IsRead  | IsResponse | IsHWPrefetch | NeedsResponse,
 193         InvalidateReq   = IsInvalidate | IsRequest,
 194         WriteInvalidateReq = IsWrite | IsInvalidate | IsRequest,
 195         UpgradeReq      = IsInvalidate | IsRequest | NeedsResponse,
 196         UpgradeResp     = IsInvalidate | IsResponse | NeedsResponse,
 197         ReadExReq       = IsRead | IsInvalidate | IsRequest | NeedsResponse,
 198         ReadExResp      = IsRead | IsInvalidate | IsResponse | NeedsResponse
 199     };
 200
 201     /** Return the string name of the cmd field (for debugging and
 202      *   tracing). */
 203     const std::string &cmdString() const;
 204
 205     /** Reutrn the string to a cmd given by idx. */
 206     const std::string &cmdIdxToString(Command idx);
 207
 208     /** Return the index of this command. */
 209     inline int cmdToIndex() const { return (int) cmd; }
 210
 211     /** The command field of the packet. */
 212     Command cmd;
 213
 214     bool isRead()        { return (cmd & IsRead)  != 0; }
 215     bool isWrite()       { return (cmd & IsWrite) != 0; }
 216     bool isRequest()     { return (cmd & IsRequest)  != 0; }
 217     bool isResponse()    { return (cmd & IsResponse) != 0; }
 218     bool needsResponse() { return (cmd & NeedsResponse) != 0; }
 219     bool isInvalidate()  { return (cmd * IsInvalidate) != 0; }
 220
 221     bool isCacheFill() { return (flags & CACHE_LINE_FILL) != 0; }
 222     bool isNoAllocate() { return (flags & NO_ALLOCATE) != 0; }
 223     bool isCompressed() { return (flags & COMPRESSED) != 0; }
 224
 225     bool nic_pkt() { assert("Unimplemented\n" && 0); }
 226
 227     /** Possible results of a packet's request. */
 228     enum Result
 229     {
 230         Success,
 231         BadAddress,
 232         Nacked,
 233         Unknown
 234     };
 235
 236     /** The result of this packet's request. */
 237     Result result;
 238
 239     /** Accessor function that returns the source index of the packet. */
 240     short getSrc() const { assert(srcValid); return src; }
 241     void setSrc(short _src) { src = _src; srcValid = true; }
 242
 243     /** Accessor function that returns the destination index of
 244         the packet. */
 245     short getDest() const { return dest; }
 246     void setDest(short _dest) { dest = _dest; }
 247
 248     Addr getAddr() const { assert(addrSizeValid); return addr; }
 249     int getSize() const { assert(addrSizeValid); return size; }
 250     Addr getOffset(int blkSize) const { return addr & (Addr)(blkSize - 1); }
 251
 252     void addrOverride(Addr newAddr) { assert(addrSizeValid); addr = newAddr; }
 253     void cmdOverride(Command newCmd) { cmd = newCmd; }
 254
 255     /** Constructor.  Note that a Request object must be constructed
 256      *   first, but the Requests's physical address and size fields
 257      *   need not be valid. The command and destination addresses
 258      *   must be supplied.  */
 259     Packet(Request *_req, Command _cmd, short _dest)
 260         :  data(NULL), staticData(false), dynamicData(false), arrayData(false),
 261            addr(_req->paddr), size(_req->size), dest(_dest),
 262            addrSizeValid(_req->validPaddr),
 263            srcValid(false),
 264            req(_req), coherence(NULL), senderState(NULL), cmd(_cmd),
 265            result(Unknown)
 266     {
 267         flags = 0;
 268     }
 269
 270     /** Alternate constructor if you are trying to create a packet with
 271      *  a request that is for a whole block, not the address from the req.
 272      *  this allows for overriding the size/addr of the req.*/
 273     Packet(Request *_req, Command _cmd, short _dest, int _blkSize)
 274         :  data(NULL), staticData(false), dynamicData(false), arrayData(false),
 275            addr(_req->paddr & ~(_blkSize - 1)), size(_blkSize),
 276            dest(_dest),
 277            addrSizeValid(_req->validPaddr), srcValid(false),
 278            req(_req), coherence(NULL), senderState(NULL), cmd(_cmd),
 279            result(Unknown)
 280     {
 281         flags = 0;
 282     }
 283
 284     /** Destructor. */
 285     ~Packet()
 286     { deleteData(); }
 287
 288     /** Reinitialize packet address and size from the associated
 289      *   Request object, and reset other fields that may have been
 290      *   modified by a previous transaction.  Typically called when a
 291      *   statically allocated Request/Packet pair is reused for
 292      *   multiple transactions. */
 293     void reinitFromRequest() {
 294         assert(req->validPaddr);
 295         addr = req->paddr;
 296         size = req->size;
 297         addrSizeValid = true;
 298         result = Unknown;
 299         if (dynamicData) {
 300             deleteData();
 301             dynamicData = false;
 302             arrayData = false;
 303         }
 304     }
 305
 306     /** Take a request packet and modify it in place to be suitable
 307      *   for returning as a response to that request.  Used for timing
 308      *   accesses only.  For atomic and functional accesses, the
 309      *   request packet is always implicitly passed back *without*
 310      *   modifying the command or destination fields, so this function
 311      *   should not be called. */
 312     void makeTimingResponse() {
 313         assert(needsResponse());
 314         assert(isRequest());
 315         int icmd = (int)cmd;
 316         icmd &= ~(IsRequest);
 317         icmd |= IsResponse;
 318         cmd = (Command)icmd;
 319         dest = src;
 320         srcValid = false;
 321     }
 322
 323     /** Take a request packet that has been returned as NACKED and modify it so
 324      * that it can be sent out again. Only packets that need a response can be
 325      * NACKED, so verify that that is true. */
 326     void reinitNacked() {
 327         assert(needsResponse() && result == Nacked);
 328         dest =  Broadcast;
 329         result = Unknown;
 330     }
 331
 332
 333     /** Set the data pointer to the following value that should not be freed. */
 334     template <typename T>
 335     void dataStatic(T *p);
 336
 337     /** Set the data pointer to a value that should have delete [] called on it.
 338      */
 339     template <typename T>
 340     void dataDynamicArray(T *p);
 341
 342     /** set the data pointer to a value that should have delete called on it. */
 343     template <typename T>
 344     void dataDynamic(T *p);
 345
 346     /** return the value of what is pointed to in the packet. */
 347     template <typename T>
 348     T get();
 349
 350     /** get a pointer to the data ptr. */
 351     template <typename T>
 352     T* getPtr();
 353
 354     /** set the value in the data pointer to v. */
 355     template <typename T>
 356     void set(T v);
 357
 358     /** delete the data pointed to in the data pointer. Ok to call to matter how
 359      * data was allocted. */
 360     void deleteData();
 361
 362     /** If there isn't data in the packet, allocate some. */
 363     void allocate();
 364
 365     /** Do the packet modify the same addresses. */
 366     bool intersect(Packet *p);
 367 };
 368
 369 bool fixPacket(Packet *func, Packet *timing);
 370 #endif //__MEM_PACKET_HH