packet.hh revision 4022
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 <cassert> 42#include <list> 43#include <bitset> 44 45#include "base/misc.hh" 46#include "mem/request.hh" 47#include "sim/host.hh" 48#include "sim/root.hh" 49 50 51struct Packet; 52typedef Packet *PacketPtr; 53typedef uint8_t* PacketDataPtr; 54typedef std::list<PacketPtr> PacketList; 55 56//Coherence Flags 57#define NACKED_LINE (1 << 0) 58#define SATISFIED (1 << 1) 59#define SHARED_LINE (1 << 2) 60#define CACHE_LINE_FILL (1 << 3) 61#define COMPRESSED (1 << 4) 62#define NO_ALLOCATE (1 << 5) 63#define SNOOP_COMMIT (1 << 6) 64 65 66class MemCmd 67{ 68 public: 69 70 /** List of all commands associated with a packet. */ 71 enum Command 72 { 73 InvalidCmd, 74 ReadReq, 75 WriteReq, 76 WriteReqNoAck, 77 ReadResp, 78 WriteResp, 79 Writeback, 80 SoftPFReq, 81 HardPFReq, 82 SoftPFResp, 83 HardPFResp, 84 InvalidateReq, 85 WriteInvalidateReq, 86 WriteInvalidateResp, 87 UpgradeReq, 88 ReadExReq, 89 ReadExResp, 90 NUM_MEM_CMDS 91 }; 92 93 private: 94 /** List of command attributes. */ 95 enum Attribute 96 { 97 IsRead, 98 IsWrite, 99 IsPrefetch, 100 IsInvalidate, 101 IsRequest, 102 IsResponse, 103 NeedsResponse, 104 IsSWPrefetch, 105 IsHWPrefetch, 106 IsUpgrade, 107 HasData, 108 NUM_COMMAND_ATTRIBUTES 109 }; 110 111 /** Structure that defines attributes and other data associated 112 * with a Command. */ 113 struct CommandInfo { 114 /** Set of attribute flags. */ 115 const std::bitset<NUM_COMMAND_ATTRIBUTES> attributes; 116 /** Corresponding response for requests; InvalidCmd if no 117 * response is applicable. */ 118 const Command response; 119 /** String representation (for printing) */ 120 const std::string str; 121 }; 122 123 /** Array to map Command enum to associated info. */ 124 static const CommandInfo commandInfo[]; 125 126 private: 127 128 Command cmd; 129 130 bool testCmdAttrib(MemCmd::Attribute attrib) const { 131 return commandInfo[cmd].attributes[attrib] != 0; 132 } 133 134 public: 135 136 bool isRead() const { return testCmdAttrib(IsRead); } 137 bool isWrite() const { return testCmdAttrib(IsWrite); } 138 bool isRequest() const { return testCmdAttrib(IsRequest); } 139 bool isResponse() const { return testCmdAttrib(IsResponse); } 140 bool needsResponse() const { return testCmdAttrib(NeedsResponse); } 141 bool isInvalidate() const { return testCmdAttrib(IsInvalidate); } 142 bool hasData() const { return testCmdAttrib(HasData); } 143 144 const Command responseCommand() const { 145 return commandInfo[cmd].response; 146 } 147 148 /** Return the string to a cmd given by idx. */ 149 const std::string &toString() const { 150 return commandInfo[cmd].str; 151 } 152 153 int toInt() const { return (int)cmd; } 154 155 MemCmd(Command _cmd) 156 : cmd(_cmd) 157 { } 158 159 MemCmd(int _cmd) 160 : cmd((Command)_cmd) 161 { } 162 163 MemCmd() 164 : cmd(InvalidCmd) 165 { } 166 167 bool operator==(MemCmd c2) { return (cmd == c2.cmd); } 168 bool operator!=(MemCmd c2) { return (cmd != c2.cmd); } 169 170 friend class Packet; 171}; 172 173/** 174 * A Packet is used to encapsulate a transfer between two objects in 175 * the memory system (e.g., the L1 and L2 cache). (In contrast, a 176 * single Request travels all the way from the requester to the 177 * ultimate destination and back, possibly being conveyed by several 178 * different Packets along the way.) 179 */ 180class Packet 181{ 182 public: 183 184 typedef MemCmd::Command Command; 185 186 /** Temporary FLAGS field until cache gets working, this should be in coherence/sender state. */ 187 uint64_t flags; 188 189 private: 190 /** A pointer to the data being transfered. It can be differnt 191 * sizes at each level of the heirarchy so it belongs in the 192 * packet, not request. This may or may not be populated when a 193 * responder recieves the packet. If not populated it memory 194 * should be allocated. 195 */ 196 PacketDataPtr data; 197 198 /** Is the data pointer set to a value that shouldn't be freed 199 * when the packet is destroyed? */ 200 bool staticData; 201 /** The data pointer points to a value that should be freed when 202 * the packet is destroyed. */ 203 bool dynamicData; 204 /** the data pointer points to an array (thus delete [] ) needs to 205 * be called on it rather than simply delete.*/ 206 bool arrayData; 207 208 /** The address of the request. This address could be virtual or 209 * physical, depending on the system configuration. */ 210 Addr addr; 211 212 /** The size of the request or transfer. */ 213 int size; 214 215 /** Device address (e.g., bus ID) of the source of the 216 * transaction. The source is not responsible for setting this 217 * field; it is set implicitly by the interconnect when the 218 * packet is first sent. */ 219 short src; 220 221 /** Device address (e.g., bus ID) of the destination of the 222 * transaction. The special value Broadcast indicates that the 223 * packet should be routed based on its address. This field is 224 * initialized in the constructor and is thus always valid 225 * (unlike * addr, size, and src). */ 226 short dest; 227 228 /** Are the 'addr' and 'size' fields valid? */ 229 bool addrSizeValid; 230 /** Is the 'src' field valid? */ 231 bool srcValid; 232 233 234 public: 235 236 /** Used to calculate latencies for each packet.*/ 237 Tick time; 238 239 /** The time at which the packet will be fully transmitted */ 240 Tick finishTime; 241 242 /** The time at which the first chunk of the packet will be transmitted */ 243 Tick firstWordTime; 244 245 /** The special destination address indicating that the packet 246 * should be routed based on its address. */ 247 static const short Broadcast = -1; 248 249 /** A pointer to the original request. */ 250 RequestPtr req; 251 252 /** A virtual base opaque structure used to hold coherence-related 253 * state. A specific subclass would be derived from this to 254 * carry state specific to a particular coherence protocol. */ 255 class CoherenceState { 256 public: 257 virtual ~CoherenceState() {} 258 }; 259 260 /** This packet's coherence state. Caches should use 261 * dynamic_cast<> to cast to the state appropriate for the 262 * system's coherence protocol. */ 263 CoherenceState *coherence; 264 265 /** A virtual base opaque structure used to hold state associated 266 * with the packet but specific to the sending device (e.g., an 267 * MSHR). A pointer to this state is returned in the packet's 268 * response so that the sender can quickly look up the state 269 * needed to process it. A specific subclass would be derived 270 * from this to carry state specific to a particular sending 271 * device. */ 272 class SenderState { 273 public: 274 virtual ~SenderState() {} 275 }; 276 277 /** This packet's sender state. Devices should use dynamic_cast<> 278 * to cast to the state appropriate to the sender. */ 279 SenderState *senderState; 280 281 public: 282 283 /** The command field of the packet. */ 284 MemCmd cmd; 285 286 /** Return the string name of the cmd field (for debugging and 287 * tracing). */ 288 const std::string &cmdString() const { return cmd.toString(); } 289 290 /** Return the index of this command. */ 291 inline int cmdToIndex() const { return cmd.toInt(); } 292 293 public: 294 295 bool isRead() const { return cmd.isRead(); } 296 bool isWrite() const { return cmd.isWrite(); } 297 bool isRequest() const { return cmd.isRequest(); } 298 bool isResponse() const { return cmd.isResponse(); } 299 bool needsResponse() const { return cmd.needsResponse(); } 300 bool isInvalidate() const { return cmd.isInvalidate(); } 301 bool hasData() const { return cmd.hasData(); } 302 303 bool isCacheFill() const { return (flags & CACHE_LINE_FILL) != 0; } 304 bool isNoAllocate() const { return (flags & NO_ALLOCATE) != 0; } 305 bool isCompressed() const { return (flags & COMPRESSED) != 0; } 306 307 bool nic_pkt() { panic("Unimplemented"); M5_DUMMY_RETURN } 308 309 /** Possible results of a packet's request. */ 310 enum Result 311 { 312 Success, 313 BadAddress, 314 Nacked, 315 Unknown 316 }; 317 318 /** The result of this packet's request. */ 319 Result result; 320 321 /** Accessor function that returns the source index of the packet. */ 322 short getSrc() const { assert(srcValid); return src; } 323 void setSrc(short _src) { src = _src; srcValid = true; } 324 325 /** Accessor function that returns the destination index of 326 the packet. */ 327 short getDest() const { return dest; } 328 void setDest(short _dest) { dest = _dest; } 329 330 Addr getAddr() const { assert(addrSizeValid); return addr; } 331 int getSize() const { assert(addrSizeValid); return size; } 332 Addr getOffset(int blkSize) const { return addr & (Addr)(blkSize - 1); } 333 334 void addrOverride(Addr newAddr) { assert(addrSizeValid); addr = newAddr; } 335 void cmdOverride(MemCmd newCmd) { cmd = newCmd; } 336 337 /** Constructor. Note that a Request object must be constructed 338 * first, but the Requests's physical address and size fields 339 * need not be valid. The command and destination addresses 340 * must be supplied. */ 341 Packet(Request *_req, MemCmd _cmd, short _dest) 342 : data(NULL), staticData(false), dynamicData(false), arrayData(false), 343 addr(_req->paddr), size(_req->size), dest(_dest), 344 addrSizeValid(_req->validPaddr), 345 srcValid(false), 346 req(_req), coherence(NULL), senderState(NULL), cmd(_cmd), 347 result(Unknown) 348 { 349 flags = 0; 350 time = curTick; 351 } 352 353 /** Alternate constructor if you are trying to create a packet with 354 * a request that is for a whole block, not the address from the req. 355 * this allows for overriding the size/addr of the req.*/ 356 Packet(Request *_req, MemCmd _cmd, short _dest, int _blkSize) 357 : data(NULL), staticData(false), dynamicData(false), arrayData(false), 358 addr(_req->paddr & ~(_blkSize - 1)), size(_blkSize), 359 dest(_dest), 360 addrSizeValid(_req->validPaddr), srcValid(false), 361 req(_req), coherence(NULL), senderState(NULL), cmd(_cmd), 362 result(Unknown) 363 { 364 flags = 0; 365 time = curTick; 366 } 367 368 /** Destructor. */ 369 ~Packet() 370 { if (staticData || dynamicData) deleteData(); } 371 372 /** Reinitialize packet address and size from the associated 373 * Request object, and reset other fields that may have been 374 * modified by a previous transaction. Typically called when a 375 * statically allocated Request/Packet pair is reused for 376 * multiple transactions. */ 377 void reinitFromRequest() { 378 assert(req->validPaddr); 379 flags = 0; 380 addr = req->paddr; 381 size = req->size; 382 time = req->time; 383 addrSizeValid = true; 384 result = Unknown; 385 if (dynamicData) { 386 deleteData(); 387 dynamicData = false; 388 arrayData = false; 389 } 390 } 391 392 /** Take a request packet and modify it in place to be suitable 393 * for returning as a response to that request. Used for timing 394 * accesses only. For atomic and functional accesses, the 395 * request packet is always implicitly passed back *without* 396 * modifying the destination fields, so this function 397 * should not be called. */ 398 void makeTimingResponse() { 399 assert(needsResponse()); 400 assert(isRequest()); 401 cmd = cmd.responseCommand(); 402 dest = src; 403 srcValid = false; 404 } 405 406 /** 407 * Take a request packet and modify it in place to be suitable for 408 * returning as a response to that request. 409 */ 410 void makeAtomicResponse() 411 { 412 assert(needsResponse()); 413 assert(isRequest()); 414 cmd = cmd.responseCommand(); 415 } 416 417 /** 418 * Take a request packet that has been returned as NACKED and 419 * modify it so that it can be sent out again. Only packets that 420 * need a response can be NACKED, so verify that that is true. 421 */ 422 void 423 reinitNacked() 424 { 425 assert(needsResponse() && result == Nacked); 426 dest = Broadcast; 427 result = Unknown; 428 } 429 430 431 /** 432 * Set the data pointer to the following value that should not be 433 * freed. 434 */ 435 template <typename T> 436 void 437 dataStatic(T *p) 438 { 439 if(dynamicData) 440 dynamicData = false; 441 data = (PacketDataPtr)p; 442 staticData = true; 443 } 444 445 /** 446 * Set the data pointer to a value that should have delete [] 447 * called on it. 448 */ 449 template <typename T> 450 void 451 dataDynamicArray(T *p) 452 { 453 assert(!staticData && !dynamicData); 454 data = (PacketDataPtr)p; 455 dynamicData = true; 456 arrayData = true; 457 } 458 459 /** 460 * set the data pointer to a value that should have delete called 461 * on it. 462 */ 463 template <typename T> 464 void 465 dataDynamic(T *p) 466 { 467 assert(!staticData && !dynamicData); 468 data = (PacketDataPtr)p; 469 dynamicData = true; 470 arrayData = false; 471 } 472 473 /** get a pointer to the data ptr. */ 474 template <typename T> 475 T* 476 getPtr() 477 { 478 assert(staticData || dynamicData); 479 return (T*)data; 480 } 481 482 /** return the value of what is pointed to in the packet. */ 483 template <typename T> 484 T get(); 485 486 /** set the value in the data pointer to v. */ 487 template <typename T> 488 void set(T v); 489 490 /** 491 * delete the data pointed to in the data pointer. Ok to call to 492 * matter how data was allocted. 493 */ 494 void deleteData(); 495 496 /** If there isn't data in the packet, allocate some. */ 497 void allocate(); 498 499 /** Do the packet modify the same addresses. */ 500 bool intersect(PacketPtr p); 501}; 502 503/** This function given a functional packet and a timing packet either satisfies 504 * the timing packet, or updates the timing packet to reflect the updated state 505 * in the timing packet. It returns if the functional packet should continue to 506 * traverse the memory hierarchy or not. 507 */ 508bool fixPacket(PacketPtr func, PacketPtr timing); 509 510/** This function is a wrapper for the fixPacket field that toggles the hasData bit 511 * it is used when a response is waiting in the caches, but hasn't been marked as a 512 * response yet (so the fixPacket needs to get the correct value for the hasData) 513 */ 514bool fixDelayedResponsePacket(PacketPtr func, PacketPtr timing); 515 516std::ostream & operator<<(std::ostream &o, const Packet &p); 517 518#endif //__MEM_PACKET_HH 519