packet.hh revision 3940
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 44#include "base/misc.hh" 45#include "mem/request.hh" 46#include "sim/host.hh" 47#include "sim/root.hh" 48 49 50struct Packet; 51typedef Packet *PacketPtr; 52typedef uint8_t* PacketDataPtr; 53typedef std::list<PacketPtr> PacketList; 54 55//Coherence Flags 56#define NACKED_LINE (1 << 0) 57#define SATISFIED (1 << 1) 58#define SHARED_LINE (1 << 2) 59#define CACHE_LINE_FILL (1 << 3) 60#define COMPRESSED (1 << 4) 61#define NO_ALLOCATE (1 << 5) 62#define SNOOP_COMMIT (1 << 6) 63 64//for now. @todo fix later 65#define NUM_MEM_CMDS (1 << 11) 66/** 67 * A Packet is used to encapsulate a transfer between two objects in 68 * the memory system (e.g., the L1 and L2 cache). (In contrast, a 69 * single Request travels all the way from the requester to the 70 * ultimate destination and back, possibly being conveyed by several 71 * different Packets along the way.) 72 */ 73class Packet 74{ 75 public: 76 /** Temporary FLAGS field until cache gets working, this should be in coherence/sender state. */ 77 uint64_t flags; 78 79 private: 80 /** A pointer to the data being transfered. It can be differnt 81 * sizes at each level of the heirarchy so it belongs in the 82 * packet, not request. This may or may not be populated when a 83 * responder recieves the packet. If not populated it memory 84 * should be allocated. 85 */ 86 PacketDataPtr data; 87 88 /** Is the data pointer set to a value that shouldn't be freed 89 * when the packet is destroyed? */ 90 bool staticData; 91 /** The data pointer points to a value that should be freed when 92 * the packet is destroyed. */ 93 bool dynamicData; 94 /** the data pointer points to an array (thus delete [] ) needs to 95 * be called on it rather than simply delete.*/ 96 bool arrayData; 97 98 /** The address of the request. This address could be virtual or 99 * physical, depending on the system configuration. */ 100 Addr addr; 101 102 /** The size of the request or transfer. */ 103 int size; 104 105 /** Device address (e.g., bus ID) of the source of the 106 * transaction. The source is not responsible for setting this 107 * field; it is set implicitly by the interconnect when the 108 * packet is first sent. */ 109 short src; 110 111 /** Device address (e.g., bus ID) of the destination of the 112 * transaction. The special value Broadcast indicates that the 113 * packet should be routed based on its address. This field is 114 * initialized in the constructor and is thus always valid 115 * (unlike * addr, size, and src). */ 116 short dest; 117 118 /** Are the 'addr' and 'size' fields valid? */ 119 bool addrSizeValid; 120 /** Is the 'src' field valid? */ 121 bool srcValid; 122 123 124 public: 125 126 /** Used to calculate latencies for each packet.*/ 127 Tick time; 128 129 /** The time at which the packet will be fully transmitted */ 130 Tick finishTime; 131 132 /** The time at which the first chunk of the packet will be transmitted */ 133 Tick firstWordTime; 134 135 /** The special destination address indicating that the packet 136 * should be routed based on its address. */ 137 static const short Broadcast = -1; 138 139 /** A pointer to the original request. */ 140 RequestPtr req; 141 142 /** A virtual base opaque structure used to hold coherence-related 143 * state. A specific subclass would be derived from this to 144 * carry state specific to a particular coherence protocol. */ 145 class CoherenceState { 146 public: 147 virtual ~CoherenceState() {} 148 }; 149 150 /** This packet's coherence state. Caches should use 151 * dynamic_cast<> to cast to the state appropriate for the 152 * system's coherence protocol. */ 153 CoherenceState *coherence; 154 155 /** A virtual base opaque structure used to hold state associated 156 * with the packet but specific to the sending device (e.g., an 157 * MSHR). A pointer to this state is returned in the packet's 158 * response so that the sender can quickly look up the state 159 * needed to process it. A specific subclass would be derived 160 * from this to carry state specific to a particular sending 161 * device. */ 162 class SenderState { 163 public: 164 virtual ~SenderState() {} 165 }; 166 167 /** This packet's sender state. Devices should use dynamic_cast<> 168 * to cast to the state appropriate to the sender. */ 169 SenderState *senderState; 170 171 private: 172 /** List of command attributes. */ 173 // If you add a new CommandAttribute, make sure to increase NUM_MEM_CMDS 174 // as well. 175 enum CommandAttribute 176 { 177 IsRead = 1 << 0, 178 IsWrite = 1 << 1, 179 IsPrefetch = 1 << 2, 180 IsInvalidate = 1 << 3, 181 IsRequest = 1 << 4, 182 IsResponse = 1 << 5, 183 NeedsResponse = 1 << 6, 184 IsSWPrefetch = 1 << 7, 185 IsHWPrefetch = 1 << 8, 186 IsUpgrade = 1 << 9, 187 HasData = 1 << 10 188 }; 189 190 public: 191 /** List of all commands associated with a packet. */ 192 enum Command 193 { 194 InvalidCmd = 0, 195 ReadReq = IsRead | IsRequest | NeedsResponse, 196 WriteReq = IsWrite | IsRequest | NeedsResponse | HasData, 197 WriteReqNoAck = IsWrite | IsRequest | HasData, 198 ReadResp = IsRead | IsResponse | NeedsResponse | HasData, 199 WriteResp = IsWrite | IsResponse | NeedsResponse, 200 Writeback = IsWrite | IsRequest | HasData, 201 SoftPFReq = IsRead | IsRequest | IsSWPrefetch | NeedsResponse, 202 HardPFReq = IsRead | IsRequest | IsHWPrefetch | NeedsResponse, 203 SoftPFResp = IsRead | IsResponse | IsSWPrefetch 204 | NeedsResponse | HasData, 205 HardPFResp = IsRead | IsResponse | IsHWPrefetch 206 | NeedsResponse | HasData, 207 InvalidateReq = IsInvalidate | IsRequest, 208 WriteInvalidateReq = IsWrite | IsInvalidate | IsRequest 209 | HasData | NeedsResponse, 210 WriteInvalidateResp = IsWrite | IsInvalidate | IsRequest 211 | NeedsResponse | IsResponse, 212 UpgradeReq = IsInvalidate | IsRequest | IsUpgrade, 213 ReadExReq = IsRead | IsInvalidate | IsRequest | NeedsResponse, 214 ReadExResp = IsRead | IsInvalidate | IsResponse 215 | NeedsResponse | HasData 216 }; 217 218 /** Return the string name of the cmd field (for debugging and 219 * tracing). */ 220 const std::string &cmdString() const; 221 222 /** Reutrn the string to a cmd given by idx. */ 223 const std::string &cmdIdxToString(Command idx); 224 225 /** Return the index of this command. */ 226 inline int cmdToIndex() const { return (int) cmd; } 227 228 /** The command field of the packet. */ 229 Command cmd; 230 231 bool isRead() const { return (cmd & IsRead) != 0; } 232 bool isWrite() const { return (cmd & IsWrite) != 0; } 233 bool isRequest() const { return (cmd & IsRequest) != 0; } 234 bool isResponse() const { return (cmd & IsResponse) != 0; } 235 bool needsResponse() const { return (cmd & NeedsResponse) != 0; } 236 bool isInvalidate() const { return (cmd & IsInvalidate) != 0; } 237 bool hasData() const { return (cmd & HasData) != 0; } 238 239 bool isCacheFill() const { return (flags & CACHE_LINE_FILL) != 0; } 240 bool isNoAllocate() const { return (flags & NO_ALLOCATE) != 0; } 241 bool isCompressed() const { return (flags & COMPRESSED) != 0; } 242 243 bool nic_pkt() { panic("Unimplemented"); M5_DUMMY_RETURN } 244 245 /** Possible results of a packet's request. */ 246 enum Result 247 { 248 Success, 249 BadAddress, 250 Nacked, 251 Unknown 252 }; 253 254 /** The result of this packet's request. */ 255 Result result; 256 257 /** Accessor function that returns the source index of the packet. */ 258 short getSrc() const { assert(srcValid); return src; } 259 void setSrc(short _src) { src = _src; srcValid = true; } 260 261 /** Accessor function that returns the destination index of 262 the packet. */ 263 short getDest() const { return dest; } 264 void setDest(short _dest) { dest = _dest; } 265 266 Addr getAddr() const { assert(addrSizeValid); return addr; } 267 int getSize() const { assert(addrSizeValid); return size; } 268 Addr getOffset(int blkSize) const { return addr & (Addr)(blkSize - 1); } 269 270 void addrOverride(Addr newAddr) { assert(addrSizeValid); addr = newAddr; } 271 void cmdOverride(Command newCmd) { cmd = newCmd; } 272 273 /** Constructor. Note that a Request object must be constructed 274 * first, but the Requests's physical address and size fields 275 * need not be valid. The command and destination addresses 276 * must be supplied. */ 277 Packet(Request *_req, Command _cmd, short _dest) 278 : data(NULL), staticData(false), dynamicData(false), arrayData(false), 279 addr(_req->paddr), size(_req->size), dest(_dest), 280 addrSizeValid(_req->validPaddr), 281 srcValid(false), 282 req(_req), coherence(NULL), senderState(NULL), cmd(_cmd), 283 result(Unknown) 284 { 285 flags = 0; 286 time = curTick; 287 } 288 289 /** Alternate constructor if you are trying to create a packet with 290 * a request that is for a whole block, not the address from the req. 291 * this allows for overriding the size/addr of the req.*/ 292 Packet(Request *_req, Command _cmd, short _dest, int _blkSize) 293 : data(NULL), staticData(false), dynamicData(false), arrayData(false), 294 addr(_req->paddr & ~(_blkSize - 1)), size(_blkSize), 295 dest(_dest), 296 addrSizeValid(_req->validPaddr), srcValid(false), 297 req(_req), coherence(NULL), senderState(NULL), cmd(_cmd), 298 result(Unknown) 299 { 300 flags = 0; 301 time = curTick; 302 } 303 304 /** Destructor. */ 305 ~Packet() 306 { if (staticData || dynamicData) deleteData(); } 307 308 /** Reinitialize packet address and size from the associated 309 * Request object, and reset other fields that may have been 310 * modified by a previous transaction. Typically called when a 311 * statically allocated Request/Packet pair is reused for 312 * multiple transactions. */ 313 void reinitFromRequest() { 314 assert(req->validPaddr); 315 flags = 0; 316 addr = req->paddr; 317 size = req->size; 318 time = req->time; 319 addrSizeValid = true; 320 result = Unknown; 321 if (dynamicData) { 322 deleteData(); 323 dynamicData = false; 324 arrayData = false; 325 } 326 } 327 328 /** Take a request packet and modify it in place to be suitable 329 * for returning as a response to that request. Used for timing 330 * accesses only. For atomic and functional accesses, the 331 * request packet is always implicitly passed back *without* 332 * modifying the destination fields, so this function 333 * should not be called. */ 334 void makeTimingResponse() { 335 assert(needsResponse()); 336 assert(isRequest()); 337 int icmd = (int)cmd; 338 icmd &= ~(IsRequest); 339 icmd |= IsResponse; 340 if (isRead()) 341 icmd |= HasData; 342 if (isWrite()) 343 icmd &= ~HasData; 344 cmd = (Command)icmd; 345 dest = src; 346 srcValid = false; 347 } 348 349 350 void toggleData() { 351 int icmd = (int)cmd; 352 icmd ^= HasData; 353 cmd = (Command)icmd; 354 } 355 356 /** 357 * Take a request packet and modify it in place to be suitable for 358 * returning as a response to that request. 359 */ 360 void makeAtomicResponse() 361 { 362 assert(needsResponse()); 363 assert(isRequest()); 364 int icmd = (int)cmd; 365 icmd &= ~(IsRequest); 366 icmd |= IsResponse; 367 if (isRead()) 368 icmd |= HasData; 369 if (isWrite()) 370 icmd &= ~HasData; 371 cmd = (Command)icmd; 372 } 373 374 /** 375 * Take a request packet that has been returned as NACKED and 376 * modify it so that it can be sent out again. Only packets that 377 * need a response can be NACKED, so verify that that is true. 378 */ 379 void 380 reinitNacked() 381 { 382 assert(needsResponse() && result == Nacked); 383 dest = Broadcast; 384 result = Unknown; 385 } 386 387 388 /** 389 * Set the data pointer to the following value that should not be 390 * freed. 391 */ 392 template <typename T> 393 void 394 dataStatic(T *p) 395 { 396 if(dynamicData) 397 dynamicData = false; 398 data = (PacketDataPtr)p; 399 staticData = true; 400 } 401 402 /** 403 * Set the data pointer to a value that should have delete [] 404 * called on it. 405 */ 406 template <typename T> 407 void 408 dataDynamicArray(T *p) 409 { 410 assert(!staticData && !dynamicData); 411 data = (PacketDataPtr)p; 412 dynamicData = true; 413 arrayData = true; 414 } 415 416 /** 417 * set the data pointer to a value that should have delete called 418 * on it. 419 */ 420 template <typename T> 421 void 422 dataDynamic(T *p) 423 { 424 assert(!staticData && !dynamicData); 425 data = (PacketDataPtr)p; 426 dynamicData = true; 427 arrayData = false; 428 } 429 430 /** get a pointer to the data ptr. */ 431 template <typename T> 432 T* 433 getPtr() 434 { 435 assert(staticData || dynamicData); 436 return (T*)data; 437 } 438 439 /** return the value of what is pointed to in the packet. */ 440 template <typename T> 441 T get(); 442 443 /** set the value in the data pointer to v. */ 444 template <typename T> 445 void set(T v); 446 447 /** 448 * delete the data pointed to in the data pointer. Ok to call to 449 * matter how data was allocted. 450 */ 451 void deleteData(); 452 453 /** If there isn't data in the packet, allocate some. */ 454 void allocate(); 455 456 /** Do the packet modify the same addresses. */ 457 bool intersect(PacketPtr p); 458}; 459 460/** This function given a functional packet and a timing packet either satisfies 461 * the timing packet, or updates the timing packet to reflect the updated state 462 * in the timing packet. It returns if the functional packet should continue to 463 * traverse the memory hierarchy or not. 464 */ 465bool fixPacket(PacketPtr func, PacketPtr timing); 466 467/** This function is a wrapper for the fixPacket field that toggles the hasData bit 468 * it is used when a response is waiting in the caches, but hasn't been marked as a 469 * response yet (so the fixPacket needs to get the correct value for the hasData) 470 */ 471bool fixDelayedResponsePacket(PacketPtr func, PacketPtr timing); 472 473std::ostream & operator<<(std::ostream &o, const Packet &p); 474 475#endif //__MEM_PACKET_HH 476