packet.hh revision 5314
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 "base/printable.hh" 49#include "mem/request.hh" 50#include "sim/host.hh" 51#include "sim/core.hh" 52 53 54struct Packet; 55typedef Packet *PacketPtr; 56typedef uint8_t* PacketDataPtr; 57typedef std::list<PacketPtr> PacketList; 58 59class MemCmd 60{ 61 public: 62 63 /** List of all commands associated with a packet. */ 64 enum Command 65 { 66 InvalidCmd, 67 ReadReq, 68 ReadResp, 69 WriteReq, 70 WriteResp, 71 Writeback, 72 SoftPFReq, 73 HardPFReq, 74 SoftPFResp, 75 HardPFResp, 76 WriteInvalidateReq, 77 WriteInvalidateResp, 78 UpgradeReq, 79 UpgradeResp, 80 ReadExReq, 81 ReadExResp, 82 LoadLockedReq, 83 LoadLockedResp, 84 StoreCondReq, 85 StoreCondResp, 86 SwapReq, 87 SwapResp, 88 // Error responses 89 // @TODO these should be classified as responses rather than 90 // requests; coding them as requests initially for backwards 91 // compatibility 92 NetworkNackError, // nacked at network layer (not by protocol) 93 InvalidDestError, // packet dest field invalid 94 BadAddressError, // memory address invalid 95 // Fake simulator-only commands 96 PrintReq, // Print state matching address 97 NUM_MEM_CMDS 98 }; 99 100 private: 101 /** List of command attributes. */ 102 enum Attribute 103 { 104 IsRead, //!< Data flows from responder to requester 105 IsWrite, //!< Data flows from requester to responder 106 IsPrefetch, //!< Not a demand access 107 IsInvalidate, 108 NeedsExclusive, //!< Requires exclusive copy to complete in-cache 109 IsRequest, //!< Issued by requester 110 IsResponse, //!< Issue by responder 111 NeedsResponse, //!< Requester needs response from target 112 IsSWPrefetch, 113 IsHWPrefetch, 114 IsLocked, //!< Alpha/MIPS LL or SC access 115 HasData, //!< There is an associated payload 116 IsError, //!< Error response 117 IsPrint, //!< Print state matching address (for debugging) 118 NUM_COMMAND_ATTRIBUTES 119 }; 120 121 /** Structure that defines attributes and other data associated 122 * with a Command. */ 123 struct CommandInfo { 124 /** Set of attribute flags. */ 125 const std::bitset<NUM_COMMAND_ATTRIBUTES> attributes; 126 /** Corresponding response for requests; InvalidCmd if no 127 * response is applicable. */ 128 const Command response; 129 /** String representation (for printing) */ 130 const std::string str; 131 }; 132 133 /** Array to map Command enum to associated info. */ 134 static const CommandInfo commandInfo[]; 135 136 private: 137 138 Command cmd; 139 140 bool testCmdAttrib(MemCmd::Attribute attrib) const { 141 return commandInfo[cmd].attributes[attrib] != 0; 142 } 143 144 public: 145 146 bool isRead() const { return testCmdAttrib(IsRead); } 147 bool isWrite() const { return testCmdAttrib(IsWrite); } 148 bool isRequest() const { return testCmdAttrib(IsRequest); } 149 bool isResponse() const { return testCmdAttrib(IsResponse); } 150 bool needsExclusive() const { return testCmdAttrib(NeedsExclusive); } 151 bool needsResponse() const { return testCmdAttrib(NeedsResponse); } 152 bool isInvalidate() const { return testCmdAttrib(IsInvalidate); } 153 bool hasData() const { return testCmdAttrib(HasData); } 154 bool isReadWrite() const { return isRead() && isWrite(); } 155 bool isLocked() const { return testCmdAttrib(IsLocked); } 156 bool isError() const { return testCmdAttrib(IsError); } 157 bool isPrint() const { return testCmdAttrib(IsPrint); } 158 159 const Command responseCommand() const { 160 return commandInfo[cmd].response; 161 } 162 163 /** Return the string to a cmd given by idx. */ 164 const std::string &toString() const { 165 return commandInfo[cmd].str; 166 } 167 168 int toInt() const { return (int)cmd; } 169 170 MemCmd(Command _cmd) 171 : cmd(_cmd) 172 { } 173 174 MemCmd(int _cmd) 175 : cmd((Command)_cmd) 176 { } 177 178 MemCmd() 179 : cmd(InvalidCmd) 180 { } 181 182 bool operator==(MemCmd c2) { return (cmd == c2.cmd); } 183 bool operator!=(MemCmd c2) { return (cmd != c2.cmd); } 184 185 friend class Packet; 186}; 187 188/** 189 * A Packet is used to encapsulate a transfer between two objects in 190 * the memory system (e.g., the L1 and L2 cache). (In contrast, a 191 * single Request travels all the way from the requester to the 192 * ultimate destination and back, possibly being conveyed by several 193 * different Packets along the way.) 194 */ 195class Packet : public FastAlloc, public Printable 196{ 197 public: 198 199 typedef MemCmd::Command Command; 200 201 /** The command field of the packet. */ 202 MemCmd cmd; 203 204 /** A pointer to the original request. */ 205 RequestPtr req; 206 207 private: 208 /** A pointer to the data being transfered. It can be differnt 209 * sizes at each level of the heirarchy so it belongs in the 210 * packet, not request. This may or may not be populated when a 211 * responder recieves the packet. If not populated it memory 212 * should be allocated. 213 */ 214 PacketDataPtr data; 215 216 /** Is the data pointer set to a value that shouldn't be freed 217 * when the packet is destroyed? */ 218 bool staticData; 219 /** The data pointer points to a value that should be freed when 220 * the packet is destroyed. */ 221 bool dynamicData; 222 /** the data pointer points to an array (thus delete [] ) needs to 223 * be called on it rather than simply delete.*/ 224 bool arrayData; 225 226 /** The address of the request. This address could be virtual or 227 * physical, depending on the system configuration. */ 228 Addr addr; 229 230 /** The size of the request or transfer. */ 231 int size; 232 233 /** Device address (e.g., bus ID) of the source of the 234 * transaction. The source is not responsible for setting this 235 * field; it is set implicitly by the interconnect when the 236 * packet is first sent. */ 237 short src; 238 239 /** Device address (e.g., bus ID) of the destination of the 240 * transaction. The special value Broadcast indicates that the 241 * packet should be routed based on its address. This field is 242 * initialized in the constructor and is thus always valid 243 * (unlike * addr, size, and src). */ 244 short dest; 245 246 /** The original value of the command field. Only valid when the 247 * current command field is an error condition; in that case, the 248 * previous contents of the command field are copied here. This 249 * field is *not* set on non-error responses. 250 */ 251 MemCmd origCmd; 252 253 /** Are the 'addr' and 'size' fields valid? */ 254 bool addrSizeValid; 255 /** Is the 'src' field valid? */ 256 bool srcValid; 257 bool destValid; 258 259 enum Flag { 260 // Snoop response flags 261 MemInhibit, 262 Shared, 263 // Special control flags 264 /// Special timing-mode atomic snoop for multi-level coherence. 265 ExpressSnoop, 266 /// Does supplier have exclusive copy? 267 /// Useful for multi-level coherence. 268 SupplyExclusive, 269 NUM_PACKET_FLAGS 270 }; 271 272 /** Status flags */ 273 std::bitset<NUM_PACKET_FLAGS> flags; 274 275 public: 276 277 /** Used to calculate latencies for each packet.*/ 278 Tick time; 279 280 /** The time at which the packet will be fully transmitted */ 281 Tick finishTime; 282 283 /** The time at which the first chunk of the packet will be transmitted */ 284 Tick firstWordTime; 285 286 /** The special destination address indicating that the packet 287 * should be routed based on its address. */ 288 static const short Broadcast = -1; 289 290 /** A virtual base opaque structure used to hold state associated 291 * with the packet but specific to the sending device (e.g., an 292 * MSHR). A pointer to this state is returned in the packet's 293 * response so that the sender can quickly look up the state 294 * needed to process it. A specific subclass would be derived 295 * from this to carry state specific to a particular sending 296 * device. */ 297 class SenderState : public FastAlloc { 298 public: 299 virtual ~SenderState() {} 300 }; 301 302 class PrintReqState : public SenderState { 303 class LabelStackEntry { 304 public: 305 const std::string label; 306 std::string *prefix; 307 bool labelPrinted; 308 LabelStackEntry(const std::string &_label, 309 std::string *_prefix); 310 }; 311 312 typedef std::list<LabelStackEntry> LabelStack; 313 LabelStack labelStack; 314 315 std::string *curPrefixPtr; 316 317 public: 318 std::ostream &os; 319 const int verbosity; 320 321 PrintReqState(std::ostream &os, int verbosity = 0); 322 ~PrintReqState(); 323 324 const std::string &curPrefix() { return *curPrefixPtr; } 325 void pushLabel(const std::string &lbl, 326 const std::string &prefix = " "); 327 void popLabel(); 328 void printLabels(); 329 void printObj(Printable *obj); 330 }; 331 332 /** This packet's sender state. Devices should use dynamic_cast<> 333 * to cast to the state appropriate to the sender. */ 334 SenderState *senderState; 335 336 /** Return the string name of the cmd field (for debugging and 337 * tracing). */ 338 const std::string &cmdString() const { return cmd.toString(); } 339 340 /** Return the index of this command. */ 341 inline int cmdToIndex() const { return cmd.toInt(); } 342 343 bool isRead() const { return cmd.isRead(); } 344 bool isWrite() const { return cmd.isWrite(); } 345 bool isRequest() const { return cmd.isRequest(); } 346 bool isResponse() const { return cmd.isResponse(); } 347 bool needsExclusive() const { return cmd.needsExclusive(); } 348 bool needsResponse() const { return cmd.needsResponse(); } 349 bool isInvalidate() const { return cmd.isInvalidate(); } 350 bool hasData() const { return cmd.hasData(); } 351 bool isReadWrite() const { return cmd.isReadWrite(); } 352 bool isLocked() const { return cmd.isLocked(); } 353 bool isError() const { return cmd.isError(); } 354 bool isPrint() const { return cmd.isPrint(); } 355 356 // Snoop flags 357 void assertMemInhibit() { flags[MemInhibit] = true; } 358 bool memInhibitAsserted() { return flags[MemInhibit]; } 359 void assertShared() { flags[Shared] = true; } 360 bool sharedAsserted() { return flags[Shared]; } 361 362 // Special control flags 363 void setExpressSnoop() { flags[ExpressSnoop] = true; } 364 bool isExpressSnoop() { return flags[ExpressSnoop]; } 365 void setSupplyExclusive() { flags[SupplyExclusive] = true; } 366 bool isSupplyExclusive() { return flags[SupplyExclusive]; } 367 368 // Network error conditions... encapsulate them as methods since 369 // their encoding keeps changing (from result field to command 370 // field, etc.) 371 void setNacked() { assert(isResponse()); cmd = MemCmd::NetworkNackError; } 372 void setBadAddress() { assert(isResponse()); cmd = MemCmd::BadAddressError; } 373 bool wasNacked() { return cmd == MemCmd::NetworkNackError; } 374 bool hadBadAddress() { return cmd == MemCmd::BadAddressError; } 375 void copyError(Packet *pkt) { assert(pkt->isError()); cmd = pkt->cmd; } 376 377 bool nic_pkt() { panic("Unimplemented"); M5_DUMMY_RETURN } 378 379 /** Accessor function that returns the source index of the packet. */ 380 short getSrc() const { assert(srcValid); return src; } 381 void setSrc(short _src) { src = _src; srcValid = true; } 382 /** Reset source field, e.g. to retransmit packet on different bus. */ 383 void clearSrc() { srcValid = false; } 384 385 /** Accessor function that returns the destination index of 386 the packet. */ 387 short getDest() const { assert(destValid); return dest; } 388 void setDest(short _dest) { dest = _dest; destValid = true; } 389 390 Addr getAddr() const { assert(addrSizeValid); return addr; } 391 int getSize() const { assert(addrSizeValid); return size; } 392 Addr getOffset(int blkSize) const { return addr & (Addr)(blkSize - 1); } 393 394 /** Constructor. Note that a Request object must be constructed 395 * first, but the Requests's physical address and size fields 396 * need not be valid. The command and destination addresses 397 * must be supplied. */ 398 Packet(Request *_req, MemCmd _cmd, short _dest) 399 : cmd(_cmd), req(_req), 400 data(NULL), staticData(false), dynamicData(false), arrayData(false), 401 addr(_req->paddr), size(_req->size), dest(_dest), 402 addrSizeValid(_req->validPaddr), srcValid(false), destValid(true), 403 flags(0), time(curTick), senderState(NULL) 404 { 405 } 406 407 /** Alternate constructor if you are trying to create a packet with 408 * a request that is for a whole block, not the address from the req. 409 * this allows for overriding the size/addr of the req.*/ 410 Packet(Request *_req, MemCmd _cmd, short _dest, int _blkSize) 411 : cmd(_cmd), req(_req), 412 data(NULL), staticData(false), dynamicData(false), arrayData(false), 413 addr(_req->paddr & ~(_blkSize - 1)), size(_blkSize), dest(_dest), 414 addrSizeValid(_req->validPaddr), srcValid(false), destValid(true), 415 flags(0), time(curTick), senderState(NULL) 416 { 417 } 418 419 /** Alternate constructor for copying a packet. Copy all fields 420 * *except* if the original packet's data was dynamic, don't copy 421 * that, as we can't guarantee that the new packet's lifetime is 422 * less than that of the original packet. In this case the new 423 * packet should allocate its own data. */ 424 Packet(Packet *origPkt, bool clearFlags = false) 425 : cmd(origPkt->cmd), req(origPkt->req), 426 data(origPkt->staticData ? origPkt->data : NULL), 427 staticData(origPkt->staticData), 428 dynamicData(false), arrayData(false), 429 addr(origPkt->addr), size(origPkt->size), 430 src(origPkt->src), dest(origPkt->dest), 431 addrSizeValid(origPkt->addrSizeValid), 432 srcValid(origPkt->srcValid), destValid(origPkt->destValid), 433 flags(clearFlags ? 0 : origPkt->flags), 434 time(curTick), senderState(origPkt->senderState) 435 { 436 } 437 438 /** Destructor. */ 439 ~Packet() 440 { if (staticData || dynamicData) deleteData(); } 441 442 /** Reinitialize packet address and size from the associated 443 * Request object, and reset other fields that may have been 444 * modified by a previous transaction. Typically called when a 445 * statically allocated Request/Packet pair is reused for 446 * multiple transactions. */ 447 void reinitFromRequest() { 448 assert(req->validPaddr); 449 flags = 0; 450 addr = req->paddr; 451 size = req->size; 452 time = req->time; 453 addrSizeValid = true; 454 if (dynamicData) { 455 deleteData(); 456 dynamicData = false; 457 arrayData = false; 458 } 459 } 460 461 /** 462 * Take a request packet and modify it in place to be suitable for 463 * returning as a response to that request. The source and 464 * destination fields are *not* modified, as is appropriate for 465 * atomic accesses. 466 */ 467 void makeResponse() 468 { 469 assert(needsResponse()); 470 assert(isRequest()); 471 origCmd = cmd; 472 cmd = cmd.responseCommand(); 473 dest = src; 474 destValid = srcValid; 475 srcValid = false; 476 } 477 478 void makeAtomicResponse() 479 { 480 makeResponse(); 481 } 482 483 void makeTimingResponse() 484 { 485 makeResponse(); 486 } 487 488 /** 489 * Take a request packet that has been returned as NACKED and 490 * modify it so that it can be sent out again. Only packets that 491 * need a response can be NACKED, so verify that that is true. 492 */ 493 void 494 reinitNacked() 495 { 496 assert(wasNacked()); 497 cmd = origCmd; 498 assert(needsResponse()); 499 setDest(Broadcast); 500 } 501 502 503 /** 504 * Set the data pointer to the following value that should not be 505 * freed. 506 */ 507 template <typename T> 508 void 509 dataStatic(T *p) 510 { 511 if(dynamicData) 512 dynamicData = false; 513 data = (PacketDataPtr)p; 514 staticData = true; 515 } 516 517 /** 518 * Set the data pointer to a value that should have delete [] 519 * called on it. 520 */ 521 template <typename T> 522 void 523 dataDynamicArray(T *p) 524 { 525 assert(!staticData && !dynamicData); 526 data = (PacketDataPtr)p; 527 dynamicData = true; 528 arrayData = true; 529 } 530 531 /** 532 * set the data pointer to a value that should have delete called 533 * on it. 534 */ 535 template <typename T> 536 void 537 dataDynamic(T *p) 538 { 539 assert(!staticData && !dynamicData); 540 data = (PacketDataPtr)p; 541 dynamicData = true; 542 arrayData = false; 543 } 544 545 /** get a pointer to the data ptr. */ 546 template <typename T> 547 T* 548 getPtr() 549 { 550 assert(staticData || dynamicData); 551 return (T*)data; 552 } 553 554 /** return the value of what is pointed to in the packet. */ 555 template <typename T> 556 T get(); 557 558 /** set the value in the data pointer to v. */ 559 template <typename T> 560 void set(T v); 561 562 /** 563 * Copy data into the packet from the provided pointer. 564 */ 565 void setData(uint8_t *p) 566 { 567 std::memcpy(getPtr<uint8_t>(), p, getSize()); 568 } 569 570 /** 571 * Copy data into the packet from the provided block pointer, 572 * which is aligned to the given block size. 573 */ 574 void setDataFromBlock(uint8_t *blk_data, int blkSize) 575 { 576 setData(blk_data + getOffset(blkSize)); 577 } 578 579 /** 580 * Copy data from the packet to the provided block pointer, which 581 * is aligned to the given block size. 582 */ 583 void writeData(uint8_t *p) 584 { 585 std::memcpy(p, getPtr<uint8_t>(), getSize()); 586 } 587 588 /** 589 * Copy data from the packet to the memory at the provided pointer. 590 */ 591 void writeDataToBlock(uint8_t *blk_data, int blkSize) 592 { 593 writeData(blk_data + getOffset(blkSize)); 594 } 595 596 /** 597 * delete the data pointed to in the data pointer. Ok to call to 598 * matter how data was allocted. 599 */ 600 void deleteData(); 601 602 /** If there isn't data in the packet, allocate some. */ 603 void allocate(); 604 605 /** 606 * Check a functional request against a memory value represented 607 * by a base/size pair and an associated data array. If the 608 * functional request is a read, it may be satisfied by the memory 609 * value. If the functional request is a write, it may update the 610 * memory value. 611 */ 612 bool checkFunctional(Printable *obj, Addr base, int size, uint8_t *data); 613 614 /** 615 * Check a functional request against a memory value stored in 616 * another packet (i.e. an in-transit request or response). If 617 * possible, the request will be satisfied and transformed 618 * in-place into a response (at which point no further checking 619 * need be done). 620 * 621 * @return True if the memory location addressed by the request 622 * overlaps with the location addressed by otherPkt. 623 */ 624 bool checkFunctional(PacketPtr otherPkt) { 625 return checkFunctional(otherPkt, 626 otherPkt->getAddr(), otherPkt->getSize(), 627 otherPkt->hasData() ? 628 otherPkt->getPtr<uint8_t>() : NULL); 629 } 630 631 void pushLabel(const std::string &lbl) { 632 if (isPrint()) { 633 dynamic_cast<PrintReqState*>(senderState)->pushLabel(lbl); 634 } 635 } 636 637 void popLabel() { 638 if (isPrint()) { 639 dynamic_cast<PrintReqState*>(senderState)->popLabel(); 640 } 641 } 642 643 void print(std::ostream &o, int verbosity = 0, 644 const std::string &prefix = "") const; 645}; 646 647#endif //__MEM_PACKET_HH 648