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 "sim/host.hh"
  43 #include "sim/root.hh"
  44 #include <list>
  45 #include <cassert>
  46
  47 struct Packet;
  48 typedef Packet* PacketPtr;
  49 typedef uint8_t* PacketDataPtr;
  50 typedef std::list<PacketPtr> PacketList;
  51
  52 //Coherence Flags
  53 #define NACKED_LINE 1 << 0
  54 #define SATISFIED 1 << 1
  55 #define SHARED_LINE 1 << 2
  56 #define CACHE_LINE_FILL 1 << 3
  57 #define COMPRESSED 1 << 4
  58 #define NO_ALLOCATE 1 << 5
  59 #define SNOOP_COMMIT 1 << 6
  60
  61 /**
  62  * A Packet is used to encapsulate a transfer between two objects in
  63  * the memory system (e.g., the L1 and L2 cache).  (In contrast, a
  64  * single Request travels all the way from the requester to the
  65  * ultimate destination and back, possibly being conveyed by several
  66  * different Packets along the way.)
  67  */
  68 class Packet
  69 {
  70   public:
  71     /** Temporary FLAGS field until cache gets working, this should be in coherence/sender state. */
  72     uint64_t flags;
  73
  74   private:
  75    /** A pointer to the data being transfered.  It can be differnt
  76     *    sizes at each level of the heirarchy so it belongs in the
  77     *    packet, not request. This may or may not be populated when a
  78     *    responder recieves the packet. If not populated it memory
  79     *    should be allocated.
  80     */
  81     PacketDataPtr data;
  82
  83     /** Is the data pointer set to a value that shouldn't be freed
  84      *   when the packet is destroyed? */
  85     bool staticData;
  86     /** The data pointer points to a value that should be freed when
  87      *   the packet is destroyed. */
  88     bool dynamicData;
  89     /** the data pointer points to an array (thus delete [] ) needs to
  90      *   be called on it rather than simply delete.*/
  91     bool arrayData;
  92
  93
  94     /** The address of the request.  This address could be virtual or
  95      *   physical, depending on the system configuration. */
  96     Addr addr;
  97
  98      /** The size of the request or transfer. */
  99     int size;
 100
 101     /** Device address (e.g., bus ID) of the source of the
 102      *   transaction. The source is not responsible for setting this
 103      *   field; it is set implicitly by the interconnect when the
 104      *   packet * is first sent.  */
 105     short src;
 106
 107     /** Device address (e.g., bus ID) of the destination of the
 108      *   transaction. The special value Broadcast indicates that the
 109      *   packet should be routed based on its address. This field is
 110      *   initialized in the constructor and is thus always valid
 111      *   (unlike * addr, size, and src). */
 112     short dest;
 113
 114     /** Are the 'addr' and 'size' fields valid? */
 115     bool addrSizeValid;
 116     /** Is the 'src' field valid? */
 117     bool srcValid;
 118
 119
 120   public:
 121
 122     /** Used to calculate latencies for each packet.*/
 123     Tick time;
 124
 125     /** The special destination address indicating that the packet
 126      *   should be routed based on its address. */
 127     static const short Broadcast = -1;
 128
 129     /** A pointer to the original request. */
 130     RequestPtr req;
 131
 132     /** A virtual base opaque structure used to hold coherence-related
 133      *    state.  A specific subclass would be derived from this to
 134      *    carry state specific to a particular coherence protocol.  */
 135     class CoherenceState {
 136       public:
 137         virtual ~CoherenceState() {}
 138     };
 139
 140     /** This packet's coherence state.  Caches should use
 141      *   dynamic_cast<> to cast to the state appropriate for the
 142      *   system's coherence protocol.  */
 143     CoherenceState *coherence;
 144
 145     /** A virtual base opaque structure used to hold state associated
 146      *    with the packet but specific to the sending device (e.g., an
 147      *    MSHR).  A pointer to this state is returned in the packet's
 148      *    response so that the sender can quickly look up the state
 149      *    needed to process it.  A specific subclass would be derived
 150      *    from this to carry state specific to a particular sending
 151      *    device.  */
 152     class SenderState {
 153       public:
 154         virtual ~SenderState() {}
 155     };
 156
 157     /** This packet's sender state.  Devices should use dynamic_cast<>
 158      *   to cast to the state appropriate to the sender. */
 159     SenderState *senderState;
 160
 161   private:
 162     /** List of command attributes. */
 163     // If you add a new CommandAttribute, make sure to increase NUM_MEM_CMDS
 164     // as well.
 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         HasData         = 1 << 9
 177     };
 178
 179 //For statistics we need max number of commands, hard code it at
 180 //20 for now.  @todo fix later
 181 #define NUM_MEM_CMDS 1 << 10
 182
 183   public:
 184     /** List of all commands associated with a packet. */
 185     enum Command
 186     {
 187         InvalidCmd      = 0,
 188         ReadReq         = IsRead  | IsRequest | NeedsResponse,
 189         WriteReq        = IsWrite | IsRequest | NeedsResponse | HasData,
 190         WriteReqNoAck   = IsWrite | IsRequest | HasData,
 191         ReadResp        = IsRead  | IsResponse | NeedsResponse | HasData,
 192         WriteResp       = IsWrite | IsResponse | NeedsResponse,
 193         Writeback       = IsWrite | IsRequest | HasData,
 194         SoftPFReq       = IsRead  | IsRequest | IsSWPrefetch | NeedsResponse,
 195         HardPFReq       = IsRead  | IsRequest | IsHWPrefetch | NeedsResponse,
 196         SoftPFResp      = IsRead  | IsResponse | IsSWPrefetch
 197                                 | NeedsResponse | HasData,
 198         HardPFResp      = IsRead  | IsResponse | IsHWPrefetch
 199                                 | NeedsResponse | HasData,
 200         InvalidateReq   = IsInvalidate | IsRequest,
 201         WriteInvalidateReq = IsWrite | IsInvalidate | IsRequest | HasData,
 202         UpgradeReq      = IsInvalidate | IsRequest | NeedsResponse,
 203         UpgradeResp     = IsInvalidate | IsResponse | NeedsResponse,
 204         ReadExReq       = IsRead | IsInvalidate | IsRequest | NeedsResponse,
 205         ReadExResp      = IsRead | IsInvalidate | IsResponse
 206                                 | NeedsResponse | HasData
 207     };
 208
 209     /** Return the string name of the cmd field (for debugging and
 210      *   tracing). */
 211     const std::string &cmdString() const;
 212
 213     /** Reutrn the string to a cmd given by idx. */
 214     const std::string &cmdIdxToString(Command idx);
 215
 216     /** Return the index of this command. */
 217     inline int cmdToIndex() const { return (int) cmd; }
 218
 219     /** The command field of the packet. */
 220     Command cmd;
 221
 222     bool isRead()        { return (cmd & IsRead)  != 0; }
 223     bool isWrite()       { return (cmd & IsWrite) != 0; }
 224     bool isRequest()     { return (cmd & IsRequest)  != 0; }
 225     bool isResponse()    { return (cmd & IsResponse) != 0; }
 226     bool needsResponse() { return (cmd & NeedsResponse) != 0; }
 227     bool isInvalidate()  { return (cmd & IsInvalidate) != 0; }
 228     bool hasData()       { return (cmd & HasData) != 0; }
 229
 230     bool isCacheFill() { return (flags & CACHE_LINE_FILL) != 0; }
 231     bool isNoAllocate() { return (flags & NO_ALLOCATE) != 0; }
 232     bool isCompressed() { return (flags & COMPRESSED) != 0; }
 233
 234     bool nic_pkt() { assert("Unimplemented\n" && 0); return false; }
 235
 236     /** Possible results of a packet's request. */
 237     enum Result
 238     {
 239         Success,
 240         BadAddress,
 241         Nacked,
 242         Unknown
 243     };
 244
 245     /** The result of this packet's request. */
 246     Result result;
 247
 248     /** Accessor function that returns the source index of the packet. */
 249     short getSrc() const { assert(srcValid); return src; }
 250     void setSrc(short _src) { src = _src; srcValid = true; }
 251
 252     /** Accessor function that returns the destination index of
 253         the packet. */
 254     short getDest() const { return dest; }
 255     void setDest(short _dest) { dest = _dest; }
 256
 257     Addr getAddr() const { assert(addrSizeValid); return addr; }
 258     int getSize() const { assert(addrSizeValid); return size; }
 259     Addr getOffset(int blkSize) const { return addr & (Addr)(blkSize - 1); }
 260
 261     void addrOverride(Addr newAddr) { assert(addrSizeValid); addr = newAddr; }
 262     void cmdOverride(Command newCmd) { cmd = newCmd; }
 263
 264     /** Constructor.  Note that a Request object must be constructed
 265      *   first, but the Requests's physical address and size fields
 266      *   need not be valid. The command and destination addresses
 267      *   must be supplied.  */
 268     Packet(Request *_req, Command _cmd, short _dest)
 269         :  data(NULL), staticData(false), dynamicData(false), arrayData(false),
 270            addr(_req->paddr), size(_req->size), dest(_dest),
 271            addrSizeValid(_req->validPaddr),
 272            srcValid(false),
 273            req(_req), coherence(NULL), senderState(NULL), cmd(_cmd),
 274            result(Unknown)
 275     {
 276         flags = 0;
 277         time = curTick;
 278     }
 279
 280     /** Alternate constructor if you are trying to create a packet with
 281      *  a request that is for a whole block, not the address from the req.
 282      *  this allows for overriding the size/addr of the req.*/
 283     Packet(Request *_req, Command _cmd, short _dest, int _blkSize)
 284         :  data(NULL), staticData(false), dynamicData(false), arrayData(false),
 285            addr(_req->paddr & ~(_blkSize - 1)), size(_blkSize),
 286            dest(_dest),
 287            addrSizeValid(_req->validPaddr), srcValid(false),
 288            req(_req), coherence(NULL), senderState(NULL), cmd(_cmd),
 289            result(Unknown)
 290     {
 291         flags = 0;
 292         time = curTick;
 293     }
 294
 295     /** Destructor. */
 296     ~Packet()
 297     { deleteData(); }
 298
 299     /** Reinitialize packet address and size from the associated
 300      *   Request object, and reset other fields that may have been
 301      *   modified by a previous transaction.  Typically called when a
 302      *   statically allocated Request/Packet pair is reused for
 303      *   multiple transactions. */
 304     void reinitFromRequest() {
 305         assert(req->validPaddr);
 306         addr = req->paddr;
 307         size = req->size;
 308         time = req->time;
 309         addrSizeValid = true;
 310         result = Unknown;
 311         if (dynamicData) {
 312             deleteData();
 313             dynamicData = false;
 314             arrayData = false;
 315         }
 316     }
 317
 318     /** Take a request packet and modify it in place to be suitable
 319      *   for returning as a response to that request.  Used for timing
 320      *   accesses only.  For atomic and functional accesses, the
 321      *   request packet is always implicitly passed back *without*
 322      *   modifying the command or destination fields, so this function
 323      *   should not be called. */
 324     void makeTimingResponse() {
 325         assert(needsResponse());
 326         assert(isRequest());
 327         int icmd = (int)cmd;
 328         icmd &= ~(IsRequest);
 329         icmd |= IsResponse;
 330         cmd = (Command)icmd;
 331         dest = src;
 332         srcValid = false;
 333     }
 334
 335     /** Take a request packet that has been returned as NACKED and modify it so
 336      * that it can be sent out again. Only packets that need a response can be
 337      * NACKED, so verify that that is true. */
 338     void reinitNacked() {
 339         assert(needsResponse() && result == Nacked);
 340         dest =  Broadcast;
 341         result = Unknown;
 342     }
 343
 344
 345     /** Set the data pointer to the following value that should not be freed. */
 346     template <typename T>
 347     void dataStatic(T *p);
 348
 349     /** Set the data pointer to a value that should have delete [] called on it.
 350      */
 351     template <typename T>
 352     void dataDynamicArray(T *p);
 353
 354     /** set the data pointer to a value that should have delete called on it. */
 355     template <typename T>
 356     void dataDynamic(T *p);
 357
 358     /** return the value of what is pointed to in the packet. */
 359     template <typename T>
 360     T get();
 361
 362     /** get a pointer to the data ptr. */
 363     template <typename T>
 364     T* getPtr();
 365
 366     /** set the value in the data pointer to v. */
 367     template <typename T>
 368     void set(T v);
 369
 370     /** delete the data pointed to in the data pointer. Ok to call to matter how
 371      * data was allocted. */
 372     void deleteData();
 373
 374     /** If there isn't data in the packet, allocate some. */
 375     void allocate();
 376
 377     /** Do the packet modify the same addresses. */
 378     bool intersect(Packet *p);
 379 };
 380
 381 bool fixPacket(Packet *func, Packet *timing);
 382 #endif //__MEM_PACKET_HH