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); }
138 bool needsExclusive() const { return testCmdAttrib(NeedsExclusive); }
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
231 enum SnoopFlag {
254 enum Flag {
255 // Snoop flags
256 MemInhibit,
257 Shared,
234 NUM_SNOOP_FLAGS
258 NUM_PACKET_FLAGS
259 };
260
237 /** Coherence snoopFlags for snooping */
238 std::bitset<NUM_SNOOP_FLAGS> snoopFlags;
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
255 /** A pointer to the original request. */
256 RequestPtr req;
257
258 /** A virtual base opaque structure used to hold coherence-related
259 * state. A specific subclass would be derived from this to
260 * carry state specific to a particular coherence protocol. */
261 class CoherenceState : public FastAlloc {
262 public:
263 virtual ~CoherenceState() {}
264 };
265
266 /** This packet's coherence state. Caches should use
267 * dynamic_cast<> to cast to the state appropriate for the
268 * system's coherence protocol. */
269 CoherenceState *coherence;
270
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
287 public:
288
289 /** The command field of the packet. */
290 MemCmd cmd;
291
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
299 public:
300
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(); }
305 bool needsExclusive() const { return cmd.needsExclusive(); }
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
312 void assertMemInhibit() { snoopFlags[MemInhibit] = true; }
313 void assertShared() { snoopFlags[Shared] = true; }
314 bool memInhibitAsserted() { return snoopFlags[MemInhibit]; }
315 bool sharedAsserted() { return snoopFlags[Shared]; }
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
319 /** Possible results of a packet's request. */
320 enum Result
321 {
322 Success,
323 BadAddress,
324 Nacked,
325 Unknown
326 };
327
328 /** The result of this packet's request. */
329 Result result;
330
330 /** Accessor function that returns the source index of the packet. */
332 short getSrc() const { assert(srcValid); return src; }
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. */
339 short getDest() const { return dest; }
340 void setDest(short _dest) { dest = _dest; }
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; }
343 int getSize() const { assert(addrSizeValid); return size; }
342 int getSize() const { assert(addrSizeValid); return size; }
343 Addr getOffset(int blkSize) const { return addr & (Addr)(blkSize - 1); }
344
346 void addrOverride(Addr newAddr) { assert(addrSizeValid); addr = newAddr; }
347 void cmdOverride(MemCmd newCmd) { cmd = newCmd; }
348
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)
354 : data(NULL), staticData(false), dynamicData(false), arrayData(false),
350 : cmd(_cmd), req(_req),
351 data(NULL), staticData(false), dynamicData(false), arrayData(false),
352 addr(_req->paddr), size(_req->size), dest(_dest),
356 addrSizeValid(_req->validPaddr), srcValid(false),
357 snoopFlags(0),
358 time(curTick),
359 req(_req), coherence(NULL), senderState(NULL), cmd(_cmd),
360 result(Unknown)
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)
368 : data(NULL), staticData(false), dynamicData(false), arrayData(false),
362 : cmd(_cmd), req(_req),
363 data(NULL), staticData(false), dynamicData(false), arrayData(false),
364 addr(_req->paddr & ~(_blkSize - 1)), size(_blkSize), dest(_dest),
370 addrSizeValid(_req->validPaddr), srcValid(false),
371 snoopFlags(0),
372 time(curTick),
373 req(_req), coherence(NULL), senderState(NULL), cmd(_cmd),
374 result(Unknown)
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* set data allocation as static... even if the original
372 * packet's data was dynamic, we don't want to free it when the
373 * new packet is deallocated. Note that if original packet used
374 * dynamic data, user must guarantee that the new packet's
375 * lifetime is less than that of the original packet. */
376 Packet(Packet *origPkt)
385 : data(NULL), staticData(false), dynamicData(false), arrayData(false),
377 : cmd(origPkt->cmd), req(origPkt->req),
378 data(NULL), staticData(false), dynamicData(false), arrayData(false),
379 addr(origPkt->addr), size(origPkt->size),
380 src(origPkt->src), dest(origPkt->dest),
388 addrSizeValid(origPkt->addrSizeValid), srcValid(origPkt->srcValid),
389 snoopFlags(origPkt->snoopFlags),
390 time(curTick),
391 req(origPkt->req), coherence(origPkt->coherence),
392 senderState(origPkt->senderState), cmd(origPkt->cmd),
393 result(origPkt->result)
381 addrSizeValid(origPkt->addrSizeValid),
382 srcValid(origPkt->srcValid), destValid(origPkt->destValid),
383 flags(origPkt->flags),
384 time(curTick), senderState(origPkt->senderState)
385 {
386 }
387
388 /** Destructor. */
389 ~Packet()
390 { if (staticData || dynamicData) deleteData(); }
391
392 /** Reinitialize packet address and size from the associated
393 * Request object, and reset other fields that may have been
394 * modified by a previous transaction. Typically called when a
395 * statically allocated Request/Packet pair is reused for
396 * multiple transactions. */
397 void reinitFromRequest() {
398 assert(req->validPaddr);
408 snoopFlags = 0;
399 flags = 0;
400 addr = req->paddr;
401 size = req->size;
402 time = req->time;
403 addrSizeValid = true;
413 result = Unknown;
404 if (dynamicData) {
405 deleteData();
406 dynamicData = false;
407 arrayData = false;
408 }
409 }
410
411 /**
412 * Take a request packet and modify it in place to be suitable for
413 * returning as a response to that request. The source and
414 * destination fields are *not* modified, as is appropriate for
415 * atomic accesses.
416 */
427 void makeAtomicResponse()
417 void makeResponse()
418 {
419 assert(needsResponse());
420 assert(isRequest());
431 assert(result == Unknown);
421 cmd = cmd.responseCommand();
433 result = Success;
422 dest = src;
423 destValid = srcValid;
424 srcValid = false;
425 }
426
436 /**
437 * Perform the additional work required for timing responses above
438 * and beyond atomic responses; i.e., change the destination to
439 * point back to the requester and clear the source field.
440 */
441 void convertAtomicToTimingResponse()
427 void makeAtomicResponse()
428 {
443 dest = getSrc();
444 srcValid = false;
429 makeResponse();
430 }
431
447 /**
448 * Take a request packet and modify it in place to be suitable for
449 * returning as a response to a timing request.
450 */
432 void makeTimingResponse()
433 {
453 makeAtomicResponse();
454 convertAtomicToTimingResponse();
434 makeResponse();
435 }
436
437 /**
438 * Take a request packet that has been returned as NACKED and
439 * modify it so that it can be sent out again. Only packets that
440 * need a response can be NACKED, so verify that that is true.
441 */
442 void
443 reinitNacked()
444 {
465 assert(needsResponse() && result == Nacked);
466 dest = Broadcast;
467 result = Unknown;
445 assert(wasNacked());
446 cmd = origCmd;
447 assert(needsResponse());
448 setDest(Broadcast);
449 }
450
451
452 /**
453 * Set the data pointer to the following value that should not be
454 * freed.
455 */
456 template <typename T>
457 void
458 dataStatic(T *p)
459 {
460 if(dynamicData)
461 dynamicData = false;
462 data = (PacketDataPtr)p;
463 staticData = true;
464 }
465
466 /**
467 * Set the data pointer to a value that should have delete []
468 * called on it.
469 */
470 template <typename T>
471 void
472 dataDynamicArray(T *p)
473 {
474 assert(!staticData && !dynamicData);
475 data = (PacketDataPtr)p;
476 dynamicData = true;
477 arrayData = true;
478 }
479
480 /**
481 * set the data pointer to a value that should have delete called
482 * on it.
483 */
484 template <typename T>
485 void
486 dataDynamic(T *p)
487 {
488 assert(!staticData && !dynamicData);
489 data = (PacketDataPtr)p;
490 dynamicData = true;
491 arrayData = false;
492 }
493
494 /** get a pointer to the data ptr. */
495 template <typename T>
496 T*
497 getPtr()
498 {
499 assert(staticData || dynamicData);
500 return (T*)data;
501 }
502
503 /** return the value of what is pointed to in the packet. */
504 template <typename T>
505 T get();
506
507 /** set the value in the data pointer to v. */
508 template <typename T>
509 void set(T v);
510
511 /**
512 * Copy data into the packet from the provided pointer.
513 */
514 void setData(uint8_t *p)
515 {
516 std::memcpy(getPtr<uint8_t>(), p, getSize());
517 }
518
519 /**
520 * Copy data into the packet from the provided block pointer,
521 * which is aligned to the given block size.
522 */
523 void setDataFromBlock(uint8_t *blk_data, int blkSize)
524 {
525 setData(blk_data + getOffset(blkSize));
526 }
527
528 /**
529 * Copy data from the packet to the provided block pointer, which
530 * is aligned to the given block size.
531 */
532 void writeData(uint8_t *p)
533 {
534 std::memcpy(p, getPtr<uint8_t>(), getSize());
535 }
536
537 /**
538 * Copy data from the packet to the memory at the provided pointer.
539 */
540 void writeDataToBlock(uint8_t *blk_data, int blkSize)
541 {
542 writeData(blk_data + getOffset(blkSize));
543 }
544
545 /**
546 * delete the data pointed to in the data pointer. Ok to call to
547 * matter how data was allocted.
548 */
549 void deleteData();
550
551 /** If there isn't data in the packet, allocate some. */
552 void allocate();
553
554 /** Do the packet modify the same addresses. */
555 bool intersect(PacketPtr p);
556
557 /**
558 * Check a functional request against a memory value represented
559 * by a base/size pair and an associated data array. If the
560 * functional request is a read, it may be satisfied by the memory
561 * value. If the functional request is a write, it may update the
562 * memory value.
563 */
564 bool checkFunctional(Addr base, int size, uint8_t *data);
565
566 /**
567 * Check a functional request against a memory value stored in
568 * another packet (i.e. an in-transit request or response).
569 */
570 bool checkFunctional(PacketPtr otherPkt) {
571 return (otherPkt->hasData() &&
572 checkFunctional(otherPkt->getAddr(), otherPkt->getSize(),
573 otherPkt->getPtr<uint8_t>()));
574 }
575};
576
577
578
579/** Temporary for backwards compatibility.
580 */
581inline
582bool fixPacket(PacketPtr func, PacketPtr timing) {
583 return !func->checkFunctional(timing);
584}
585
586/** This function is a wrapper for the fixPacket field that toggles
587 * the hasData bit it is used when a response is waiting in the
588 * caches, but hasn't been marked as a response yet (so the fixPacket
589 * needs to get the correct value for the hasData)
590 */
591bool fixDelayedResponsePacket(PacketPtr func, PacketPtr timing);
592
593std::ostream & operator<<(std::ostream &o, const Packet &p);
594
595#endif //__MEM_PACKET_HH