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 ReadRespWithInvalidate,
70 WriteReq,
71 WriteResp,
72 Writeback,
73 SoftPFReq,
74 HardPFReq,
75 SoftPFResp,
76 HardPFResp,
77 WriteInvalidateReq,
78 WriteInvalidateResp,
79 UpgradeReq,
80 UpgradeResp,
81 ReadExReq,
82 ReadExResp,
83 LoadLockedReq,
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 {
298 public:
299 virtual ~SenderState() {}
300 };
301
302 /**
303 * Object used to maintain state of a PrintReq. The senderState
304 * field of a PrintReq should always be of this type.
305 */
306 class PrintReqState : public SenderState, public FastAlloc {
307 /** An entry in the label stack. */
308 class LabelStackEntry {
309 public:
310 const std::string label;
311 std::string *prefix;
312 bool labelPrinted;
313 LabelStackEntry(const std::string &_label,
314 std::string *_prefix);
315 };
316
317 typedef std::list<LabelStackEntry> LabelStack;
318 LabelStack labelStack;
319
320 std::string *curPrefixPtr;
321
322 public:
323 std::ostream &os;
324 const int verbosity;
325
326 PrintReqState(std::ostream &os, int verbosity = 0);
327 ~PrintReqState();
328
329 /** Returns the current line prefix. */
330 const std::string &curPrefix() { return *curPrefixPtr; }
331
332 /** Push a label onto the label stack, and prepend the given
333 * prefix string onto the current prefix. Labels will only be
334 * printed if an object within the label's scope is
335 * printed. */
336 void pushLabel(const std::string &lbl,
337 const std::string &prefix = " ");
338 /** Pop a label off the label stack. */
339 void popLabel();
340 /** Print all of the pending unprinted labels on the
341 * stack. Called by printObj(), so normally not called by
342 * users unless bypassing printObj(). */
343 void printLabels();
344 /** Print a Printable object to os, because it matched the
345 * address on a PrintReq. */
346 void printObj(Printable *obj);
347 };
348
349 /** This packet's sender state. Devices should use dynamic_cast<>
350 * to cast to the state appropriate to the sender. */
351 SenderState *senderState;
352
353 /** Return the string name of the cmd field (for debugging and
354 * tracing). */
355 const std::string &cmdString() const { return cmd.toString(); }
356
357 /** Return the index of this command. */
358 inline int cmdToIndex() const { return cmd.toInt(); }
359
360 bool isRead() const { return cmd.isRead(); }
361 bool isWrite() const { return cmd.isWrite(); }
362 bool isRequest() const { return cmd.isRequest(); }
363 bool isResponse() const { return cmd.isResponse(); }
364 bool needsExclusive() const { return cmd.needsExclusive(); }
365 bool needsResponse() const { return cmd.needsResponse(); }
366 bool isInvalidate() const { return cmd.isInvalidate(); }
367 bool hasData() const { return cmd.hasData(); }
368 bool isReadWrite() const { return cmd.isReadWrite(); }
369 bool isLocked() const { return cmd.isLocked(); }
370 bool isError() const { return cmd.isError(); }
371 bool isPrint() const { return cmd.isPrint(); }
372
373 // Snoop flags
374 void assertMemInhibit() { flags[MemInhibit] = true; }
375 bool memInhibitAsserted() { return flags[MemInhibit]; }
376 void assertShared() { flags[Shared] = true; }
377 bool sharedAsserted() { return flags[Shared]; }
378
379 // Special control flags
380 void setExpressSnoop() { flags[ExpressSnoop] = true; }
381 bool isExpressSnoop() { return flags[ExpressSnoop]; }
382 void setSupplyExclusive() { flags[SupplyExclusive] = true; }
383 bool isSupplyExclusive() { return flags[SupplyExclusive]; }
384
385 // Network error conditions... encapsulate them as methods since
386 // their encoding keeps changing (from result field to command
387 // field, etc.)
388 void setNacked() { assert(isResponse()); cmd = MemCmd::NetworkNackError; }
389 void setBadAddress() { assert(isResponse()); cmd = MemCmd::BadAddressError; }
390 bool wasNacked() { return cmd == MemCmd::NetworkNackError; }
391 bool hadBadAddress() { return cmd == MemCmd::BadAddressError; }
392 void copyError(Packet *pkt) { assert(pkt->isError()); cmd = pkt->cmd; }
393
394 bool nic_pkt() { panic("Unimplemented"); M5_DUMMY_RETURN }
395
396 /** Accessor function that returns the source index of the packet. */
397 short getSrc() const { assert(srcValid); return src; }
398 void setSrc(short _src) { src = _src; srcValid = true; }
399 /** Reset source field, e.g. to retransmit packet on different bus. */
400 void clearSrc() { srcValid = false; }
401
402 /** Accessor function that returns the destination index of
403 the packet. */
404 short getDest() const { assert(destValid); return dest; }
405 void setDest(short _dest) { dest = _dest; destValid = true; }
406
407 Addr getAddr() const { assert(addrSizeValid); return addr; }
408 int getSize() const { assert(addrSizeValid); return size; }
409 Addr getOffset(int blkSize) const { return addr & (Addr)(blkSize - 1); }
410
411 /** Constructor. Note that a Request object must be constructed
412 * first, but the Requests's physical address and size fields
413 * need not be valid. The command and destination addresses
414 * must be supplied. */
415 Packet(Request *_req, MemCmd _cmd, short _dest)
416 : cmd(_cmd), req(_req),
417 data(NULL), staticData(false), dynamicData(false), arrayData(false),
418 addr(_req->paddr), size(_req->size), dest(_dest),
419 addrSizeValid(_req->validPaddr), srcValid(false), destValid(true),
420 flags(0), time(curTick), senderState(NULL)
421 {
422 }
423
424 /** Alternate constructor if you are trying to create a packet with
425 * a request that is for a whole block, not the address from the req.
426 * this allows for overriding the size/addr of the req.*/
427 Packet(Request *_req, MemCmd _cmd, short _dest, int _blkSize)
428 : cmd(_cmd), req(_req),
429 data(NULL), staticData(false), dynamicData(false), arrayData(false),
430 addr(_req->paddr & ~(_blkSize - 1)), size(_blkSize), dest(_dest),
431 addrSizeValid(_req->validPaddr), srcValid(false), destValid(true),
432 flags(0), time(curTick), senderState(NULL)
433 {
434 }
435
436 /** Alternate constructor for copying a packet. Copy all fields
437 * *except* if the original packet's data was dynamic, don't copy
438 * that, as we can't guarantee that the new packet's lifetime is
439 * less than that of the original packet. In this case the new
440 * packet should allocate its own data. */
441 Packet(Packet *origPkt, bool clearFlags = false)
442 : cmd(origPkt->cmd), req(origPkt->req),
443 data(origPkt->staticData ? origPkt->data : NULL),
444 staticData(origPkt->staticData),
445 dynamicData(false), arrayData(false),
446 addr(origPkt->addr), size(origPkt->size),
447 src(origPkt->src), dest(origPkt->dest),
448 addrSizeValid(origPkt->addrSizeValid),
449 srcValid(origPkt->srcValid), destValid(origPkt->destValid),
450 flags(clearFlags ? 0 : origPkt->flags),
451 time(curTick), senderState(origPkt->senderState)
452 {
453 }
454
455 /** Destructor. */
456 ~Packet()
457 {
458 // If this is a request packet for which there's no response,
459 // delete the request object here, since the requester will
460 // never get the chance.
461 if (req && isRequest() && !needsResponse())
462 delete req;
463 if (staticData || dynamicData)
464 deleteData();
465 }
466
467 /** Reinitialize packet address and size from the associated
468 * Request object, and reset other fields that may have been
469 * modified by a previous transaction. Typically called when a
470 * statically allocated Request/Packet pair is reused for
471 * multiple transactions. */
472 void reinitFromRequest() {
473 assert(req->validPaddr);
474 flags = 0;
475 addr = req->paddr;
476 size = req->size;
477 time = req->time;
478 addrSizeValid = true;
479 if (dynamicData) {
480 deleteData();
481 dynamicData = false;
482 arrayData = false;
483 }
484 }
485
486 /**
487 * Take a request packet and modify it in place to be suitable for
488 * returning as a response to that request. The source and
489 * destination fields are *not* modified, as is appropriate for
490 * atomic accesses.
491 */
492 void makeResponse()
493 {
494 assert(needsResponse());
495 assert(isRequest());
496 origCmd = cmd;
497 cmd = cmd.responseCommand();
498 dest = src;
499 destValid = srcValid;
500 srcValid = false;
501 }
502
503 void makeAtomicResponse()
504 {
505 makeResponse();
506 }
507
508 void makeTimingResponse()
509 {
510 makeResponse();
511 }
512
513 /**
514 * Take a request packet that has been returned as NACKED and
515 * modify it so that it can be sent out again. Only packets that
516 * need a response can be NACKED, so verify that that is true.
517 */
518 void
519 reinitNacked()
520 {
521 assert(wasNacked());
522 cmd = origCmd;
523 assert(needsResponse());
524 setDest(Broadcast);
525 }
526
527
528 /**
529 * Set the data pointer to the following value that should not be
530 * freed.
531 */
532 template <typename T>
533 void
534 dataStatic(T *p)
535 {
536 if(dynamicData)
537 dynamicData = false;
538 data = (PacketDataPtr)p;
539 staticData = true;
540 }
541
542 /**
543 * Set the data pointer to a value that should have delete []
544 * called on it.
545 */
546 template <typename T>
547 void
548 dataDynamicArray(T *p)
549 {
550 assert(!staticData && !dynamicData);
551 data = (PacketDataPtr)p;
552 dynamicData = true;
553 arrayData = true;
554 }
555
556 /**
557 * set the data pointer to a value that should have delete called
558 * on it.
559 */
560 template <typename T>
561 void
562 dataDynamic(T *p)
563 {
564 assert(!staticData && !dynamicData);
565 data = (PacketDataPtr)p;
566 dynamicData = true;
567 arrayData = false;
568 }
569
570 /** get a pointer to the data ptr. */
571 template <typename T>
572 T*
573 getPtr()
574 {
575 assert(staticData || dynamicData);
576 return (T*)data;
577 }
578
579 /** return the value of what is pointed to in the packet. */
580 template <typename T>
581 T get();
582
583 /** set the value in the data pointer to v. */
584 template <typename T>
585 void set(T v);
586
587 /**
588 * Copy data into the packet from the provided pointer.
589 */
590 void setData(uint8_t *p)
591 {
592 std::memcpy(getPtr<uint8_t>(), p, getSize());
593 }
594
595 /**
596 * Copy data into the packet from the provided block pointer,
597 * which is aligned to the given block size.
598 */
599 void setDataFromBlock(uint8_t *blk_data, int blkSize)
600 {
601 setData(blk_data + getOffset(blkSize));
602 }
603
604 /**
605 * Copy data from the packet to the provided block pointer, which
606 * is aligned to the given block size.
607 */
608 void writeData(uint8_t *p)
609 {
610 std::memcpy(p, getPtr<uint8_t>(), getSize());
611 }
612
613 /**
614 * Copy data from the packet to the memory at the provided pointer.
615 */
616 void writeDataToBlock(uint8_t *blk_data, int blkSize)
617 {
618 writeData(blk_data + getOffset(blkSize));
619 }
620
621 /**
622 * delete the data pointed to in the data pointer. Ok to call to
623 * matter how data was allocted.
624 */
625 void deleteData();
626
627 /** If there isn't data in the packet, allocate some. */
628 void allocate();
629
630 /**
631 * Check a functional request against a memory value represented
632 * by a base/size pair and an associated data array. If the
633 * functional request is a read, it may be satisfied by the memory
634 * value. If the functional request is a write, it may update the
635 * memory value.
636 */
637 bool checkFunctional(Printable *obj, Addr base, int size, uint8_t *data);
638
639 /**
640 * Check a functional request against a memory value stored in
641 * another packet (i.e. an in-transit request or response).
642 */
643 bool checkFunctional(PacketPtr otherPkt) {
644 return checkFunctional(otherPkt,
645 otherPkt->getAddr(), otherPkt->getSize(),
646 otherPkt->hasData() ?
647 otherPkt->getPtr<uint8_t>() : NULL);
648 }
649
650 /**
651 * Push label for PrintReq (safe to call unconditionally).
652 */
653 void pushLabel(const std::string &lbl) {
654 if (isPrint()) {
655 dynamic_cast<PrintReqState*>(senderState)->pushLabel(lbl);
656 }
657 }
658
659 /**
660 * Pop label for PrintReq (safe to call unconditionally).
661 */
662 void popLabel() {
663 if (isPrint()) {
664 dynamic_cast<PrintReqState*>(senderState)->popLabel();
665 }
666 }
667
668 void print(std::ostream &o, int verbosity = 0,
669 const std::string &prefix = "") const;
670};
671
672#endif //__MEM_PACKET_HH