packet.hh revision 4887
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 flags 256 MemInhibit, 257 Shared, 258 NUM_PACKET_FLAGS 259 }; 260 261 /** Status flags */ 262 std::bitset<NUM_PACKET_FLAGS> flags; 263 264 public: 265 266 /** Used to calculate latencies for each packet.*/ 267 Tick time; 268 269 /** The time at which the packet will be fully transmitted */ 270 Tick finishTime; 271 272 /** The time at which the first chunk of the packet will be transmitted */ 273 Tick firstWordTime; 274 275 /** The special destination address indicating that the packet 276 * should be routed based on its address. */ 277 static const short Broadcast = -1; 278 279 /** A virtual base opaque structure used to hold state associated 280 * with the packet but specific to the sending device (e.g., an 281 * MSHR). A pointer to this state is returned in the packet's 282 * response so that the sender can quickly look up the state 283 * needed to process it. A specific subclass would be derived 284 * from this to carry state specific to a particular sending 285 * device. */ 286 class SenderState : public FastAlloc { 287 public: 288 virtual ~SenderState() {} 289 }; 290 291 /** This packet's sender state. Devices should use dynamic_cast<> 292 * to cast to the state appropriate to the sender. */ 293 SenderState *senderState; 294 295 /** Return the string name of the cmd field (for debugging and 296 * tracing). */ 297 const std::string &cmdString() const { return cmd.toString(); } 298 299 /** Return the index of this command. */ 300 inline int cmdToIndex() const { return cmd.toInt(); } 301 302 bool isRead() const { return cmd.isRead(); } 303 bool isWrite() const { return cmd.isWrite(); } 304 bool isRequest() const { return cmd.isRequest(); } 305 bool isResponse() const { return cmd.isResponse(); } 306 bool needsExclusive() const { return cmd.needsExclusive(); } 307 bool needsResponse() const { return cmd.needsResponse(); } 308 bool isInvalidate() const { return cmd.isInvalidate(); } 309 bool hasData() const { return cmd.hasData(); } 310 bool isReadWrite() const { return cmd.isReadWrite(); } 311 bool isLocked() const { return cmd.isLocked(); } 312 bool isError() const { return cmd.isError(); } 313 314 // Snoop flags 315 void assertMemInhibit() { flags[MemInhibit] = true; } 316 void assertShared() { flags[Shared] = true; } 317 bool memInhibitAsserted() { return flags[MemInhibit]; } 318 bool sharedAsserted() { return flags[Shared]; } 319 320 // Network error conditions... encapsulate them as methods since 321 // their encoding keeps changing (from result field to command 322 // field, etc.) 323 void setNacked() { origCmd = cmd; cmd = MemCmd::NetworkNackError; } 324 void setBadAddress() { origCmd = cmd; cmd = MemCmd::BadAddressError; } 325 bool wasNacked() { return cmd == MemCmd::NetworkNackError; } 326 bool hadBadAddress() { return cmd == MemCmd::BadAddressError; } 327 328 bool nic_pkt() { panic("Unimplemented"); M5_DUMMY_RETURN } 329 330 /** Accessor function that returns the source index of the packet. */ 331 short getSrc() const { assert(srcValid); return src; } 332 void setSrc(short _src) { src = _src; srcValid = true; } 333 /** Reset source field, e.g. to retransmit packet on different bus. */ 334 void clearSrc() { srcValid = false; } 335 336 /** Accessor function that returns the destination index of 337 the packet. */ 338 short getDest() const { assert(destValid); return dest; } 339 void setDest(short _dest) { dest = _dest; destValid = true; } 340 341 Addr getAddr() const { assert(addrSizeValid); return addr; } 342 int getSize() const { assert(addrSizeValid); return size; } 343 Addr getOffset(int blkSize) const { return addr & (Addr)(blkSize - 1); } 344 345 /** Constructor. Note that a Request object must be constructed 346 * first, but the Requests's physical address and size fields 347 * need not be valid. The command and destination addresses 348 * must be supplied. */ 349 Packet(Request *_req, MemCmd _cmd, short _dest) 350 : cmd(_cmd), req(_req), 351 data(NULL), staticData(false), dynamicData(false), arrayData(false), 352 addr(_req->paddr), size(_req->size), dest(_dest), 353 addrSizeValid(_req->validPaddr), srcValid(false), destValid(true), 354 flags(0), time(curTick), senderState(NULL) 355 { 356 } 357 358 /** Alternate constructor if you are trying to create a packet with 359 * a request that is for a whole block, not the address from the req. 360 * this allows for overriding the size/addr of the req.*/ 361 Packet(Request *_req, MemCmd _cmd, short _dest, int _blkSize) 362 : cmd(_cmd), req(_req), 363 data(NULL), staticData(false), dynamicData(false), arrayData(false), 364 addr(_req->paddr & ~(_blkSize - 1)), size(_blkSize), dest(_dest), 365 addrSizeValid(_req->validPaddr), srcValid(false), destValid(true), 366 flags(0), time(curTick), senderState(NULL) 367 { 368 } 369 370 /** Alternate constructor for copying a packet. Copy all fields 371 * *except* if the original packet's data was dynamic, don't copy 372 * that, as we can't guarantee that the new packet's lifetime is 373 * less than that of the original packet. In this case the new 374 * packet should allocate its own data. */ 375 Packet(Packet *origPkt) 376 : cmd(origPkt->cmd), req(origPkt->req), 377 data(origPkt->staticData ? origPkt->data : NULL), 378 staticData(origPkt->staticData), 379 dynamicData(false), arrayData(false), 380 addr(origPkt->addr), size(origPkt->size), 381 src(origPkt->src), dest(origPkt->dest), 382 addrSizeValid(origPkt->addrSizeValid), 383 srcValid(origPkt->srcValid), destValid(origPkt->destValid), 384 flags(origPkt->flags), 385 time(curTick), senderState(origPkt->senderState) 386 { 387 } 388 389 /** Destructor. */ 390 ~Packet() 391 { if (staticData || dynamicData) deleteData(); } 392 393 /** Reinitialize packet address and size from the associated 394 * Request object, and reset other fields that may have been 395 * modified by a previous transaction. Typically called when a 396 * statically allocated Request/Packet pair is reused for 397 * multiple transactions. */ 398 void reinitFromRequest() { 399 assert(req->validPaddr); 400 flags = 0; 401 addr = req->paddr; 402 size = req->size; 403 time = req->time; 404 addrSizeValid = true; 405 if (dynamicData) { 406 deleteData(); 407 dynamicData = false; 408 arrayData = false; 409 } 410 } 411 412 /** 413 * Take a request packet and modify it in place to be suitable for 414 * returning as a response to that request. The source and 415 * destination fields are *not* modified, as is appropriate for 416 * atomic accesses. 417 */ 418 void makeResponse() 419 { 420 assert(needsResponse()); 421 assert(isRequest()); 422 cmd = cmd.responseCommand(); 423 dest = src; 424 destValid = srcValid; 425 srcValid = false; 426 } 427 428 void makeAtomicResponse() 429 { 430 makeResponse(); 431 } 432 433 void makeTimingResponse() 434 { 435 makeResponse(); 436 } 437 438 /** 439 * Take a request packet that has been returned as NACKED and 440 * modify it so that it can be sent out again. Only packets that 441 * need a response can be NACKED, so verify that that is true. 442 */ 443 void 444 reinitNacked() 445 { 446 assert(wasNacked()); 447 cmd = origCmd; 448 assert(needsResponse()); 449 setDest(Broadcast); 450 } 451 452 453 /** 454 * Set the data pointer to the following value that should not be 455 * freed. 456 */ 457 template <typename T> 458 void 459 dataStatic(T *p) 460 { 461 if(dynamicData) 462 dynamicData = false; 463 data = (PacketDataPtr)p; 464 staticData = true; 465 } 466 467 /** 468 * Set the data pointer to a value that should have delete [] 469 * called on it. 470 */ 471 template <typename T> 472 void 473 dataDynamicArray(T *p) 474 { 475 assert(!staticData && !dynamicData); 476 data = (PacketDataPtr)p; 477 dynamicData = true; 478 arrayData = true; 479 } 480 481 /** 482 * set the data pointer to a value that should have delete called 483 * on it. 484 */ 485 template <typename T> 486 void 487 dataDynamic(T *p) 488 { 489 assert(!staticData && !dynamicData); 490 data = (PacketDataPtr)p; 491 dynamicData = true; 492 arrayData = false; 493 } 494 495 /** get a pointer to the data ptr. */ 496 template <typename T> 497 T* 498 getPtr() 499 { 500 assert(staticData || dynamicData); 501 return (T*)data; 502 } 503 504 /** return the value of what is pointed to in the packet. */ 505 template <typename T> 506 T get(); 507 508 /** set the value in the data pointer to v. */ 509 template <typename T> 510 void set(T v); 511 512 /** 513 * Copy data into the packet from the provided pointer. 514 */ 515 void setData(uint8_t *p) 516 { 517 std::memcpy(getPtr<uint8_t>(), p, getSize()); 518 } 519 520 /** 521 * Copy data into the packet from the provided block pointer, 522 * which is aligned to the given block size. 523 */ 524 void setDataFromBlock(uint8_t *blk_data, int blkSize) 525 { 526 setData(blk_data + getOffset(blkSize)); 527 } 528 529 /** 530 * Copy data from the packet to the provided block pointer, which 531 * is aligned to the given block size. 532 */ 533 void writeData(uint8_t *p) 534 { 535 std::memcpy(p, getPtr<uint8_t>(), getSize()); 536 } 537 538 /** 539 * Copy data from the packet to the memory at the provided pointer. 540 */ 541 void writeDataToBlock(uint8_t *blk_data, int blkSize) 542 { 543 writeData(blk_data + getOffset(blkSize)); 544 } 545 546 /** 547 * delete the data pointed to in the data pointer. Ok to call to 548 * matter how data was allocted. 549 */ 550 void deleteData(); 551 552 /** If there isn't data in the packet, allocate some. */ 553 void allocate(); 554 555 /** Do the packet modify the same addresses. */ 556 bool intersect(PacketPtr p); 557 558 /** 559 * Check a functional request against a memory value represented 560 * by a base/size pair and an associated data array. If the 561 * functional request is a read, it may be satisfied by the memory 562 * value. If the functional request is a write, it may update the 563 * memory value. 564 */ 565 bool checkFunctional(Addr base, int size, uint8_t *data); 566 567 /** 568 * Check a functional request against a memory value stored in 569 * another packet (i.e. an in-transit request or response). 570 */ 571 bool checkFunctional(PacketPtr otherPkt) { 572 return (otherPkt->hasData() && 573 checkFunctional(otherPkt->getAddr(), otherPkt->getSize(), 574 otherPkt->getPtr<uint8_t>())); 575 } 576}; 577 578std::ostream & operator<<(std::ostream &o, const Packet &p); 579 580#endif //__MEM_PACKET_HH 581