packet.hh revision 4921:bcf49547dae7
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/compiler.hh" 46#include "base/fast_alloc.hh" 47#include "base/misc.hh" 48#include "mem/request.hh" 49#include "sim/host.hh" 50#include "sim/core.hh" 51 52 53struct Packet; 54typedef Packet *PacketPtr; 55typedef uint8_t* PacketDataPtr; 56typedef std::list<PacketPtr> PacketList; 57 58class MemCmd 59{ 60 public: 61 62 /** List of all commands associated with a packet. */ 63 enum Command 64 { 65 InvalidCmd, 66 ReadReq, 67 ReadResp, 68 WriteReq, 69 WriteResp, 70 Writeback, 71 SoftPFReq, 72 HardPFReq, 73 SoftPFResp, 74 HardPFResp, 75 WriteInvalidateReq, 76 WriteInvalidateResp, 77 UpgradeReq, 78 UpgradeResp, 79 ReadExReq, 80 ReadExResp, 81 LoadLockedReq, 82 LoadLockedResp, 83 StoreCondReq, 84 StoreCondResp, 85 SwapReq, 86 SwapResp, 87 // Error responses 88 // @TODO these should be classified as responses rather than 89 // requests; coding them as requests initially for backwards 90 // compatibility 91 NetworkNackError, // nacked at network layer (not by protocol) 92 InvalidDestError, // packet dest field invalid 93 BadAddressError, // memory address invalid 94 NUM_MEM_CMDS 95 }; 96 97 private: 98 /** List of command attributes. */ 99 enum Attribute 100 { 101 IsRead, //!< Data flows from responder to requester 102 IsWrite, //!< Data flows from requester to responder 103 IsPrefetch, //!< Not a demand access 104 IsInvalidate, 105 NeedsExclusive, //!< Requires exclusive copy to complete in-cache 106 IsRequest, //!< Issued by requester 107 IsResponse, //!< Issue by responder 108 NeedsResponse, //!< Requester needs response from target 109 IsSWPrefetch, 110 IsHWPrefetch, 111 IsLocked, //!< Alpha/MIPS LL or SC access 112 HasData, //!< There is an associated payload 113 IsError, //!< Error response 114 NUM_COMMAND_ATTRIBUTES 115 }; 116 117 /** Structure that defines attributes and other data associated 118 * with a Command. */ 119 struct CommandInfo { 120 /** Set of attribute flags. */ 121 const std::bitset<NUM_COMMAND_ATTRIBUTES> attributes; 122 /** Corresponding response for requests; InvalidCmd if no 123 * response is applicable. */ 124 const Command response; 125 /** String representation (for printing) */ 126 const std::string str; 127 }; 128 129 /** Array to map Command enum to associated info. */ 130 static const CommandInfo commandInfo[]; 131 132 private: 133 134 Command cmd; 135 136 bool testCmdAttrib(MemCmd::Attribute attrib) const { 137 return commandInfo[cmd].attributes[attrib] != 0; 138 } 139 140 public: 141 142 bool isRead() const { return testCmdAttrib(IsRead); } 143 bool isWrite() const { return testCmdAttrib(IsWrite); } 144 bool isRequest() const { return testCmdAttrib(IsRequest); } 145 bool isResponse() const { return testCmdAttrib(IsResponse); } 146 bool needsExclusive() const { return testCmdAttrib(NeedsExclusive); } 147 bool needsResponse() const { return testCmdAttrib(NeedsResponse); } 148 bool isInvalidate() const { return testCmdAttrib(IsInvalidate); } 149 bool hasData() const { return testCmdAttrib(HasData); } 150 bool isReadWrite() const { return isRead() && isWrite(); } 151 bool isLocked() const { return testCmdAttrib(IsLocked); } 152 bool isError() const { return testCmdAttrib(IsError); } 153 154 const Command responseCommand() const { 155 return commandInfo[cmd].response; 156 } 157 158 /** Return the string to a cmd given by idx. */ 159 const std::string &toString() const { 160 return commandInfo[cmd].str; 161 } 162 163 int toInt() const { return (int)cmd; } 164 165 MemCmd(Command _cmd) 166 : cmd(_cmd) 167 { } 168 169 MemCmd(int _cmd) 170 : cmd((Command)_cmd) 171 { } 172 173 MemCmd() 174 : cmd(InvalidCmd) 175 { } 176 177 bool operator==(MemCmd c2) { return (cmd == c2.cmd); } 178 bool operator!=(MemCmd c2) { return (cmd != c2.cmd); } 179 180 friend class Packet; 181}; 182 183/** 184 * A Packet is used to encapsulate a transfer between two objects in 185 * the memory system (e.g., the L1 and L2 cache). (In contrast, a 186 * single Request travels all the way from the requester to the 187 * ultimate destination and back, possibly being conveyed by several 188 * different Packets along the way.) 189 */ 190class Packet : public FastAlloc 191{ 192 public: 193 194 typedef MemCmd::Command Command; 195 196 /** The command field of the packet. */ 197 MemCmd cmd; 198 199 /** A pointer to the original request. */ 200 RequestPtr req; 201 202 private: 203 /** A pointer to the data being transfered. It can be differnt 204 * sizes at each level of the heirarchy so it belongs in the 205 * packet, not request. This may or may not be populated when a 206 * responder recieves the packet. If not populated it memory 207 * should be allocated. 208 */ 209 PacketDataPtr data; 210 211 /** Is the data pointer set to a value that shouldn't be freed 212 * when the packet is destroyed? */ 213 bool staticData; 214 /** The data pointer points to a value that should be freed when 215 * the packet is destroyed. */ 216 bool dynamicData; 217 /** the data pointer points to an array (thus delete [] ) needs to 218 * be called on it rather than simply delete.*/ 219 bool arrayData; 220 221 /** The address of the request. This address could be virtual or 222 * physical, depending on the system configuration. */ 223 Addr addr; 224 225 /** The size of the request or transfer. */ 226 int size; 227 228 /** Device address (e.g., bus ID) of the source of the 229 * transaction. The source is not responsible for setting this 230 * field; it is set implicitly by the interconnect when the 231 * packet is first sent. */ 232 short src; 233 234 /** Device address (e.g., bus ID) of the destination of the 235 * transaction. The special value Broadcast indicates that the 236 * packet should be routed based on its address. This field is 237 * initialized in the constructor and is thus always valid 238 * (unlike * addr, size, and src). */ 239 short dest; 240 241 /** The original value of the command field. Only valid when the 242 * current command field is an error condition; in that case, the 243 * previous contents of the command field are copied here. This 244 * field is *not* set on non-error responses. 245 */ 246 MemCmd origCmd; 247 248 /** Are the 'addr' and 'size' fields valid? */ 249 bool addrSizeValid; 250 /** Is the 'src' field valid? */ 251 bool srcValid; 252 bool destValid; 253 254 enum Flag { 255 // Snoop response flags 256 MemInhibit, 257 Shared, 258 // Special control flags 259 /// Special timing-mode atomic snoop for multi-level coherence. 260 ExpressSnoop, 261 /// Does supplier have exclusive copy? 262 /// Useful for multi-level coherence. 263 SupplyExclusive, 264 NUM_PACKET_FLAGS 265 }; 266 267 /** Status flags */ 268 std::bitset<NUM_PACKET_FLAGS> flags; 269 270 public: 271 272 /** Used to calculate latencies for each packet.*/ 273 Tick time; 274 275 /** The time at which the packet will be fully transmitted */ 276 Tick finishTime; 277 278 /** The time at which the first chunk of the packet will be transmitted */ 279 Tick firstWordTime; 280 281 /** The special destination address indicating that the packet 282 * should be routed based on its address. */ 283 static const short Broadcast = -1; 284 285 /** A virtual base opaque structure used to hold state associated 286 * with the packet but specific to the sending device (e.g., an 287 * MSHR). A pointer to this state is returned in the packet's 288 * response so that the sender can quickly look up the state 289 * needed to process it. A specific subclass would be derived 290 * from this to carry state specific to a particular sending 291 * device. */ 292 class SenderState : public FastAlloc { 293 public: 294 virtual ~SenderState() {} 295 }; 296 297 /** This packet's sender state. Devices should use dynamic_cast<> 298 * to cast to the state appropriate to the sender. */ 299 SenderState *senderState; 300 301 /** Return the string name of the cmd field (for debugging and 302 * tracing). */ 303 const std::string &cmdString() const { return cmd.toString(); } 304 305 /** Return the index of this command. */ 306 inline int cmdToIndex() const { return cmd.toInt(); } 307 308 bool isRead() const { return cmd.isRead(); } 309 bool isWrite() const { return cmd.isWrite(); } 310 bool isRequest() const { return cmd.isRequest(); } 311 bool isResponse() const { return cmd.isResponse(); } 312 bool needsExclusive() const { return cmd.needsExclusive(); } 313 bool needsResponse() const { return cmd.needsResponse(); } 314 bool isInvalidate() const { return cmd.isInvalidate(); } 315 bool hasData() const { return cmd.hasData(); } 316 bool isReadWrite() const { return cmd.isReadWrite(); } 317 bool isLocked() const { return cmd.isLocked(); } 318 bool isError() const { return cmd.isError(); } 319 320 // Snoop flags 321 void assertMemInhibit() { flags[MemInhibit] = true; } 322 bool memInhibitAsserted() { return flags[MemInhibit]; } 323 void assertShared() { flags[Shared] = true; } 324 bool sharedAsserted() { return flags[Shared]; } 325 326 // Special control flags 327 void setExpressSnoop() { flags[ExpressSnoop] = true; } 328 bool isExpressSnoop() { return flags[ExpressSnoop]; } 329 void setSupplyExclusive() { flags[SupplyExclusive] = true; } 330 bool isSupplyExclusive() { return flags[SupplyExclusive]; } 331 332 // Network error conditions... encapsulate them as methods since 333 // their encoding keeps changing (from result field to command 334 // field, etc.) 335 void setNacked() { origCmd = cmd; cmd = MemCmd::NetworkNackError; } 336 void setBadAddress() { origCmd = cmd; cmd = MemCmd::BadAddressError; } 337 bool wasNacked() { return cmd == MemCmd::NetworkNackError; } 338 bool hadBadAddress() { return cmd == MemCmd::BadAddressError; } 339 340 bool nic_pkt() { panic("Unimplemented"); M5_DUMMY_RETURN } 341 342 /** Accessor function that returns the source index of the packet. */ 343 short getSrc() const { assert(srcValid); return src; } 344 void setSrc(short _src) { src = _src; srcValid = true; } 345 /** Reset source field, e.g. to retransmit packet on different bus. */ 346 void clearSrc() { srcValid = false; } 347 348 /** Accessor function that returns the destination index of 349 the packet. */ 350 short getDest() const { assert(destValid); return dest; } 351 void setDest(short _dest) { dest = _dest; destValid = true; } 352 353 Addr getAddr() const { assert(addrSizeValid); return addr; } 354 int getSize() const { assert(addrSizeValid); return size; } 355 Addr getOffset(int blkSize) const { return addr & (Addr)(blkSize - 1); } 356 357 /** Constructor. Note that a Request object must be constructed 358 * first, but the Requests's physical address and size fields 359 * need not be valid. The command and destination addresses 360 * must be supplied. */ 361 Packet(Request *_req, MemCmd _cmd, short _dest) 362 : cmd(_cmd), req(_req), 363 data(NULL), staticData(false), dynamicData(false), arrayData(false), 364 addr(_req->paddr), size(_req->size), dest(_dest), 365 addrSizeValid(_req->validPaddr), srcValid(false), destValid(true), 366 flags(0), time(curTick), senderState(NULL) 367 { 368 } 369 370 /** Alternate constructor if you are trying to create a packet with 371 * a request that is for a whole block, not the address from the req. 372 * this allows for overriding the size/addr of the req.*/ 373 Packet(Request *_req, MemCmd _cmd, short _dest, int _blkSize) 374 : cmd(_cmd), req(_req), 375 data(NULL), staticData(false), dynamicData(false), arrayData(false), 376 addr(_req->paddr & ~(_blkSize - 1)), size(_blkSize), dest(_dest), 377 addrSizeValid(_req->validPaddr), srcValid(false), destValid(true), 378 flags(0), time(curTick), senderState(NULL) 379 { 380 } 381 382 /** Alternate constructor for copying a packet. Copy all fields 383 * *except* if the original packet's data was dynamic, don't copy 384 * that, as we can't guarantee that the new packet's lifetime is 385 * less than that of the original packet. In this case the new 386 * packet should allocate its own data. */ 387 Packet(Packet *origPkt, bool clearFlags = false) 388 : cmd(origPkt->cmd), req(origPkt->req), 389 data(origPkt->staticData ? origPkt->data : NULL), 390 staticData(origPkt->staticData), 391 dynamicData(false), arrayData(false), 392 addr(origPkt->addr), size(origPkt->size), 393 src(origPkt->src), dest(origPkt->dest), 394 addrSizeValid(origPkt->addrSizeValid), 395 srcValid(origPkt->srcValid), destValid(origPkt->destValid), 396 flags(clearFlags ? 0 : origPkt->flags), 397 time(curTick), senderState(origPkt->senderState) 398 { 399 } 400 401 /** Destructor. */ 402 ~Packet() 403 { if (staticData || dynamicData) deleteData(); } 404 405 /** Reinitialize packet address and size from the associated 406 * Request object, and reset other fields that may have been 407 * modified by a previous transaction. Typically called when a 408 * statically allocated Request/Packet pair is reused for 409 * multiple transactions. */ 410 void reinitFromRequest() { 411 assert(req->validPaddr); 412 flags = 0; 413 addr = req->paddr; 414 size = req->size; 415 time = req->time; 416 addrSizeValid = true; 417 if (dynamicData) { 418 deleteData(); 419 dynamicData = false; 420 arrayData = false; 421 } 422 } 423 424 /** 425 * Take a request packet and modify it in place to be suitable for 426 * returning as a response to that request. The source and 427 * destination fields are *not* modified, as is appropriate for 428 * atomic accesses. 429 */ 430 void makeResponse() 431 { 432 assert(needsResponse()); 433 assert(isRequest()); 434 cmd = cmd.responseCommand(); 435 dest = src; 436 destValid = srcValid; 437 srcValid = false; 438 } 439 440 void makeAtomicResponse() 441 { 442 makeResponse(); 443 } 444 445 void makeTimingResponse() 446 { 447 makeResponse(); 448 } 449 450 /** 451 * Take a request packet that has been returned as NACKED and 452 * modify it so that it can be sent out again. Only packets that 453 * need a response can be NACKED, so verify that that is true. 454 */ 455 void 456 reinitNacked() 457 { 458 assert(wasNacked()); 459 cmd = origCmd; 460 assert(needsResponse()); 461 setDest(Broadcast); 462 } 463 464 465 /** 466 * Set the data pointer to the following value that should not be 467 * freed. 468 */ 469 template <typename T> 470 void 471 dataStatic(T *p) 472 { 473 if(dynamicData) 474 dynamicData = false; 475 data = (PacketDataPtr)p; 476 staticData = true; 477 } 478 479 /** 480 * Set the data pointer to a value that should have delete [] 481 * called on it. 482 */ 483 template <typename T> 484 void 485 dataDynamicArray(T *p) 486 { 487 assert(!staticData && !dynamicData); 488 data = (PacketDataPtr)p; 489 dynamicData = true; 490 arrayData = true; 491 } 492 493 /** 494 * set the data pointer to a value that should have delete called 495 * on it. 496 */ 497 template <typename T> 498 void 499 dataDynamic(T *p) 500 { 501 assert(!staticData && !dynamicData); 502 data = (PacketDataPtr)p; 503 dynamicData = true; 504 arrayData = false; 505 } 506 507 /** get a pointer to the data ptr. */ 508 template <typename T> 509 T* 510 getPtr() 511 { 512 assert(staticData || dynamicData); 513 return (T*)data; 514 } 515 516 /** return the value of what is pointed to in the packet. */ 517 template <typename T> 518 T get(); 519 520 /** set the value in the data pointer to v. */ 521 template <typename T> 522 void set(T v); 523 524 /** 525 * Copy data into the packet from the provided pointer. 526 */ 527 void setData(uint8_t *p) 528 { 529 std::memcpy(getPtr<uint8_t>(), p, getSize()); 530 } 531 532 /** 533 * Copy data into the packet from the provided block pointer, 534 * which is aligned to the given block size. 535 */ 536 void setDataFromBlock(uint8_t *blk_data, int blkSize) 537 { 538 setData(blk_data + getOffset(blkSize)); 539 } 540 541 /** 542 * Copy data from the packet to the provided block pointer, which 543 * is aligned to the given block size. 544 */ 545 void writeData(uint8_t *p) 546 { 547 std::memcpy(p, getPtr<uint8_t>(), getSize()); 548 } 549 550 /** 551 * Copy data from the packet to the memory at the provided pointer. 552 */ 553 void writeDataToBlock(uint8_t *blk_data, int blkSize) 554 { 555 writeData(blk_data + getOffset(blkSize)); 556 } 557 558 /** 559 * delete the data pointed to in the data pointer. Ok to call to 560 * matter how data was allocted. 561 */ 562 void deleteData(); 563 564 /** If there isn't data in the packet, allocate some. */ 565 void allocate(); 566 567 /** 568 * Check a functional request against a memory value represented 569 * by a base/size pair and an associated data array. If the 570 * functional request is a read, it may be satisfied by the memory 571 * value. If the functional request is a write, it may update the 572 * memory value. 573 */ 574 bool checkFunctional(Addr base, int size, uint8_t *data); 575 576 /** 577 * Check a functional request against a memory value stored in 578 * another packet (i.e. an in-transit request or response). 579 */ 580 bool checkFunctional(PacketPtr otherPkt) { 581 return (otherPkt->hasData() && 582 checkFunctional(otherPkt->getAddr(), otherPkt->getSize(), 583 otherPkt->getPtr<uint8_t>())); 584 } 585}; 586 587std::ostream & operator<<(std::ostream &o, const Packet &p); 588 589#endif //__MEM_PACKET_HH 590