packet.hh revision 3260:d9ef6d4cbe2a
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 47struct Packet; 48typedef Packet* PacketPtr; 49typedef uint8_t* PacketDataPtr; 50typedef 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//for now. @todo fix later 62#define NUM_MEM_CMDS 1 << 11 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 */ 70class 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 /** The address of the request. This address could be virtual or 96 * physical, depending on the system configuration. */ 97 Addr addr; 98 99 /** The size of the request or transfer. */ 100 int size; 101 102 /** Device address (e.g., bus ID) of the source of the 103 * transaction. The source is not responsible for setting this 104 * field; it is set implicitly by the interconnect when the 105 * packet * is first sent. */ 106 short src; 107 108 /** Device address (e.g., bus ID) of the destination of the 109 * transaction. The special value Broadcast indicates that the 110 * packet should be routed based on its address. This field is 111 * initialized in the constructor and is thus always valid 112 * (unlike * addr, size, and src). */ 113 short dest; 114 115 /** Are the 'addr' and 'size' fields valid? */ 116 bool addrSizeValid; 117 /** Is the 'src' field valid? */ 118 bool srcValid; 119 120 121 public: 122 123 /** Used to calculate latencies for each packet.*/ 124 Tick time; 125 126 /** The time at which the packet will be fully transmitted */ 127 Tick finishTime; 128 129 /** The time at which the first chunk of the packet will be transmitted */ 130 Tick firstWordTime; 131 132 /** The special destination address indicating that the packet 133 * should be routed based on its address. */ 134 static const short Broadcast = -1; 135 136 /** A pointer to the original request. */ 137 RequestPtr req; 138 139 /** A virtual base opaque structure used to hold coherence-related 140 * state. A specific subclass would be derived from this to 141 * carry state specific to a particular coherence protocol. */ 142 class CoherenceState { 143 public: 144 virtual ~CoherenceState() {} 145 }; 146 147 /** This packet's coherence state. Caches should use 148 * dynamic_cast<> to cast to the state appropriate for the 149 * system's coherence protocol. */ 150 CoherenceState *coherence; 151 152 /** A virtual base opaque structure used to hold state associated 153 * with the packet but specific to the sending device (e.g., an 154 * MSHR). A pointer to this state is returned in the packet's 155 * response so that the sender can quickly look up the state 156 * needed to process it. A specific subclass would be derived 157 * from this to carry state specific to a particular sending 158 * device. */ 159 class SenderState { 160 public: 161 virtual ~SenderState() {} 162 }; 163 164 /** This packet's sender state. Devices should use dynamic_cast<> 165 * to cast to the state appropriate to the sender. */ 166 SenderState *senderState; 167 168 private: 169 /** List of command attributes. */ 170 // If you add a new CommandAttribute, make sure to increase NUM_MEM_CMDS 171 // as well. 172 enum CommandAttribute 173 { 174 IsRead = 1 << 0, 175 IsWrite = 1 << 1, 176 IsPrefetch = 1 << 2, 177 IsInvalidate = 1 << 3, 178 IsRequest = 1 << 4, 179 IsResponse = 1 << 5, 180 NeedsResponse = 1 << 6, 181 IsSWPrefetch = 1 << 7, 182 IsHWPrefetch = 1 << 8, 183 IsUpgrade = 1 << 9, 184 HasData = 1 << 10 185 }; 186 187 public: 188 /** List of all commands associated with a packet. */ 189 enum Command 190 { 191 InvalidCmd = 0, 192 ReadReq = IsRead | IsRequest | NeedsResponse, 193 WriteReq = IsWrite | IsRequest | NeedsResponse | HasData, 194 WriteReqNoAck = IsWrite | IsRequest | HasData, 195 ReadResp = IsRead | IsResponse | NeedsResponse | HasData, 196 WriteResp = IsWrite | IsResponse | NeedsResponse, 197 Writeback = IsWrite | IsRequest | HasData, 198 SoftPFReq = IsRead | IsRequest | IsSWPrefetch | NeedsResponse, 199 HardPFReq = IsRead | IsRequest | IsHWPrefetch | NeedsResponse, 200 SoftPFResp = IsRead | IsResponse | IsSWPrefetch 201 | NeedsResponse | HasData, 202 HardPFResp = IsRead | IsResponse | IsHWPrefetch 203 | NeedsResponse | HasData, 204 InvalidateReq = IsInvalidate | IsRequest, 205 WriteInvalidateReq = IsWrite | IsInvalidate | IsRequest | HasData, 206 UpgradeReq = IsInvalidate | IsRequest | IsUpgrade, 207 ReadExReq = IsRead | IsInvalidate | IsRequest | NeedsResponse, 208 ReadExResp = IsRead | IsInvalidate | IsResponse 209 | NeedsResponse | HasData 210 }; 211 212 /** Return the string name of the cmd field (for debugging and 213 * tracing). */ 214 const std::string &cmdString() const; 215 216 /** Reutrn the string to a cmd given by idx. */ 217 const std::string &cmdIdxToString(Command idx); 218 219 /** Return the index of this command. */ 220 inline int cmdToIndex() const { return (int) cmd; } 221 222 /** The command field of the packet. */ 223 Command cmd; 224 225 bool isRead() const { return (cmd & IsRead) != 0; } 226 bool isWrite() const { return (cmd & IsWrite) != 0; } 227 bool isRequest() const { return (cmd & IsRequest) != 0; } 228 bool isResponse() const { return (cmd & IsResponse) != 0; } 229 bool needsResponse() const { return (cmd & NeedsResponse) != 0; } 230 bool isInvalidate() const { return (cmd & IsInvalidate) != 0; } 231 bool hasData() const { return (cmd & HasData) != 0; } 232 233 bool isCacheFill() const { return (flags & CACHE_LINE_FILL) != 0; } 234 bool isNoAllocate() const { return (flags & NO_ALLOCATE) != 0; } 235 bool isCompressed() const { return (flags & COMPRESSED) != 0; } 236 237 bool nic_pkt() { assert("Unimplemented\n" && 0); return false; } 238 239 /** Possible results of a packet's request. */ 240 enum Result 241 { 242 Success, 243 BadAddress, 244 Nacked, 245 Unknown 246 }; 247 248 /** The result of this packet's request. */ 249 Result result; 250 251 /** Accessor function that returns the source index of the packet. */ 252 short getSrc() const { assert(srcValid); return src; } 253 void setSrc(short _src) { src = _src; srcValid = true; } 254 255 /** Accessor function that returns the destination index of 256 the packet. */ 257 short getDest() const { return dest; } 258 void setDest(short _dest) { dest = _dest; } 259 260 Addr getAddr() const { assert(addrSizeValid); return addr; } 261 int getSize() const { assert(addrSizeValid); return size; } 262 Addr getOffset(int blkSize) const { return addr & (Addr)(blkSize - 1); } 263 264 void addrOverride(Addr newAddr) { assert(addrSizeValid); addr = newAddr; } 265 void cmdOverride(Command newCmd) { cmd = newCmd; } 266 267 /** Constructor. Note that a Request object must be constructed 268 * first, but the Requests's physical address and size fields 269 * need not be valid. The command and destination addresses 270 * must be supplied. */ 271 Packet(Request *_req, Command _cmd, short _dest) 272 : data(NULL), staticData(false), dynamicData(false), arrayData(false), 273 addr(_req->paddr), size(_req->size), dest(_dest), 274 addrSizeValid(_req->validPaddr), 275 srcValid(false), 276 req(_req), coherence(NULL), senderState(NULL), cmd(_cmd), 277 result(Unknown) 278 { 279 flags = 0; 280 time = curTick; 281 } 282 283 /** Alternate constructor if you are trying to create a packet with 284 * a request that is for a whole block, not the address from the req. 285 * this allows for overriding the size/addr of the req.*/ 286 Packet(Request *_req, Command _cmd, short _dest, int _blkSize) 287 : data(NULL), staticData(false), dynamicData(false), arrayData(false), 288 addr(_req->paddr & ~(_blkSize - 1)), size(_blkSize), 289 dest(_dest), 290 addrSizeValid(_req->validPaddr), srcValid(false), 291 req(_req), coherence(NULL), senderState(NULL), cmd(_cmd), 292 result(Unknown) 293 { 294 flags = 0; 295 time = curTick; 296 } 297 298 /** Destructor. */ 299 ~Packet() 300 { deleteData(); } 301 302 /** Reinitialize packet address and size from the associated 303 * Request object, and reset other fields that may have been 304 * modified by a previous transaction. Typically called when a 305 * statically allocated Request/Packet pair is reused for 306 * multiple transactions. */ 307 void reinitFromRequest() { 308 assert(req->validPaddr); 309 addr = req->paddr; 310 size = req->size; 311 time = req->time; 312 addrSizeValid = true; 313 result = Unknown; 314 if (dynamicData) { 315 deleteData(); 316 dynamicData = false; 317 arrayData = false; 318 } 319 } 320 321 /** Take a request packet and modify it in place to be suitable 322 * for returning as a response to that request. Used for timing 323 * accesses only. For atomic and functional accesses, the 324 * request packet is always implicitly passed back *without* 325 * modifying the destination fields, so this function 326 * should not be called. */ 327 void makeTimingResponse() { 328 assert(needsResponse()); 329 assert(isRequest()); 330 int icmd = (int)cmd; 331 icmd &= ~(IsRequest); 332 icmd |= IsResponse; 333 if (isRead()) 334 icmd |= HasData; 335 if (isWrite()) 336 icmd &= ~HasData; 337 cmd = (Command)icmd; 338 dest = src; 339 srcValid = false; 340 } 341 342 /** Take a request packet and modify it in place to be suitable 343 * for returning as a response to that request. 344 */ 345 void makeAtomicResponse() { 346 assert(needsResponse()); 347 assert(isRequest()); 348 int icmd = (int)cmd; 349 icmd &= ~(IsRequest); 350 icmd |= IsResponse; 351 cmd = (Command)icmd; 352 } 353 354 /** Take a request packet that has been returned as NACKED and modify it so 355 * that it can be sent out again. Only packets that need a response can be 356 * NACKED, so verify that that is true. */ 357 void reinitNacked() { 358 assert(needsResponse() && result == Nacked); 359 dest = Broadcast; 360 result = Unknown; 361 } 362 363 364 /** Set the data pointer to the following value that should not be freed. */ 365 template <typename T> 366 void dataStatic(T *p); 367 368 /** Set the data pointer to a value that should have delete [] called on it. 369 */ 370 template <typename T> 371 void dataDynamicArray(T *p); 372 373 /** set the data pointer to a value that should have delete called on it. */ 374 template <typename T> 375 void dataDynamic(T *p); 376 377 /** return the value of what is pointed to in the packet. */ 378 template <typename T> 379 T get(); 380 381 /** get a pointer to the data ptr. */ 382 template <typename T> 383 T* getPtr(); 384 385 /** set the value in the data pointer to v. */ 386 template <typename T> 387 void set(T v); 388 389 /** delete the data pointed to in the data pointer. Ok to call to matter how 390 * data was allocted. */ 391 void deleteData(); 392 393 /** If there isn't data in the packet, allocate some. */ 394 void allocate(); 395 396 /** Do the packet modify the same addresses. */ 397 bool intersect(Packet *p); 398}; 399 400 401/** This function given a functional packet and a timing packet either satisfies 402 * the timing packet, or updates the timing packet to reflect the updated state 403 * in the timing packet. It returns if the functional packet should continue to 404 * traverse the memory hierarchy or not. 405 */ 406bool fixPacket(Packet *func, Packet *timing); 407 408std::ostream & operator<<(std::ostream &o, const Packet &p); 409 410#endif //__MEM_PACKET_HH 411