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;

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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,

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95 InvalidDestError, // packet dest field invalid
96 BadAddressError, // memory address invalid
97 // Fake simulator-only commands
98 PrintReq, // Print state matching address
99 NUM_MEM_CMDS
100 };
101
102 private:
103 /** List of command attributes. */
104 enum Attribute
105 {
106 IsRead, //!< Data flows from responder to requester
107 IsWrite, //!< Data flows from requester to responder
108 IsPrefetch, //!< Not a demand access
109 IsInvalidate,
110 NeedsExclusive, //!< Requires exclusive copy to complete in-cache
111 IsRequest, //!< Issued by requester
112 IsResponse, //!< Issue by responder
113 NeedsResponse, //!< Requester needs response from target
114 IsSWPrefetch,
115 IsHWPrefetch,
116 IsLocked, //!< Alpha/MIPS LL or SC access
117 HasData, //!< There is an associated payload
118 IsError, //!< Error response
119 IsPrint, //!< Print state matching address (for debugging)
120 NUM_COMMAND_ATTRIBUTES
121 };
122
123 /** Structure that defines attributes and other data associated
124 * with a Command. */
125 struct CommandInfo {
126 /** Set of attribute flags. */
127 const std::bitset<NUM_COMMAND_ATTRIBUTES> attributes;
128 /** Corresponding response for requests; InvalidCmd if no
129 * response is applicable. */
130 const Command response;
131 /** String representation (for printing) */
132 const std::string str;
133 };
134
135 /** Array to map Command enum to associated info. */
136 static const CommandInfo commandInfo[];
137
138 private:
139
140 Command cmd;
141
142 bool testCmdAttrib(MemCmd::Attribute attrib) const {
143 return commandInfo[cmd].attributes[attrib] != 0;
144 }
145
146 public:
147
148 bool isRead() const { return testCmdAttrib(IsRead); }
149 bool isWrite() const { return testCmdAttrib(IsWrite); }
150 bool isRequest() const { return testCmdAttrib(IsRequest); }
151 bool isResponse() const { return testCmdAttrib(IsResponse); }
152 bool needsExclusive() const { return testCmdAttrib(NeedsExclusive); }
153 bool needsResponse() const { return testCmdAttrib(NeedsResponse); }
154 bool isInvalidate() const { return testCmdAttrib(IsInvalidate); }
155 bool hasData() const { return testCmdAttrib(HasData); }
156 bool isReadWrite() const { return isRead() && isWrite(); }
157 bool isLocked() const { return testCmdAttrib(IsLocked); }
158 bool isError() const { return testCmdAttrib(IsError); }
159 bool isPrint() const { return testCmdAttrib(IsPrint); }
160
161 const Command responseCommand() const {
162 return commandInfo[cmd].response;
163 }
164
165 /** Return the string to a cmd given by idx. */
166 const std::string &toString() const {
167 return commandInfo[cmd].str;
168 }
169
170 int toInt() const { return (int)cmd; }
171
172 MemCmd(Command _cmd)
173 : cmd(_cmd)
174 { }
175
176 MemCmd(int _cmd)
177 : cmd((Command)_cmd)
178 { }
179
180 MemCmd()
181 : cmd(InvalidCmd)
182 { }
183
184 bool operator==(MemCmd c2) { return (cmd == c2.cmd); }
185 bool operator!=(MemCmd c2) { return (cmd != c2.cmd); }
186
187 friend class Packet;
188};
189
190/**
191 * A Packet is used to encapsulate a transfer between two objects in
192 * the memory system (e.g., the L1 and L2 cache). (In contrast, a
193 * single Request travels all the way from the requester to the
194 * ultimate destination and back, possibly being conveyed by several
195 * different Packets along the way.)
196 */
197class Packet : public FastAlloc, public Printable
198{
199 public:
200
201 typedef MemCmd::Command Command;
202
203 /** The command field of the packet. */
204 MemCmd cmd;
205
206 /** A pointer to the original request. */
207 RequestPtr req;
208
209 private:
210 /** A pointer to the data being transfered. It can be differnt
211 * sizes at each level of the heirarchy so it belongs in the
212 * packet, not request. This may or may not be populated when a
213 * responder recieves the packet. If not populated it memory
214 * should be allocated.
215 */
216 PacketDataPtr data;
217
218 /** Is the data pointer set to a value that shouldn't be freed
219 * when the packet is destroyed? */
220 bool staticData;
221 /** The data pointer points to a value that should be freed when
222 * the packet is destroyed. */
223 bool dynamicData;
224 /** the data pointer points to an array (thus delete [] ) needs to
225 * be called on it rather than simply delete.*/
226 bool arrayData;
227
228 /** The address of the request. This address could be virtual or
229 * physical, depending on the system configuration. */
230 Addr addr;
231
232 /** The size of the request or transfer. */
233 int size;
234
235 /** Device address (e.g., bus ID) of the source of the
236 * transaction. The source is not responsible for setting this
237 * field; it is set implicitly by the interconnect when the
238 * packet is first sent. */
239 short src;
240
241 /** Device address (e.g., bus ID) of the destination of the
242 * transaction. The special value Broadcast indicates that the
243 * packet should be routed based on its address. This field is
244 * initialized in the constructor and is thus always valid
245 * (unlike * addr, size, and src). */
246 short dest;
247
248 /** The original value of the command field. Only valid when the
249 * current command field is an error condition; in that case, the
250 * previous contents of the command field are copied here. This
251 * field is *not* set on non-error responses.
252 */
253 MemCmd origCmd;
254
255 /** Are the 'addr' and 'size' fields valid? */
256 bool addrSizeValid;
257 /** Is the 'src' field valid? */
258 bool srcValid;
259 bool destValid;
260
261 enum Flag {
262 // Snoop response flags
263 MemInhibit,
264 Shared,
265 // Special control flags
266 /// Special timing-mode atomic snoop for multi-level coherence.
267 ExpressSnoop,
268 /// Does supplier have exclusive copy?
269 /// Useful for multi-level coherence.
270 SupplyExclusive,
271 NUM_PACKET_FLAGS
272 };
273
274 /** Status flags */
275 std::bitset<NUM_PACKET_FLAGS> flags;
276
277 public:
278
279 /** Used to calculate latencies for each packet.*/
280 Tick time;
281
282 /** The time at which the packet will be fully transmitted */
283 Tick finishTime;
284
285 /** The time at which the first chunk of the packet will be transmitted */
286 Tick firstWordTime;
287
288 /** The special destination address indicating that the packet
289 * should be routed based on its address. */
290 static const short Broadcast = -1;
291
292 /** A virtual base opaque structure used to hold state associated
293 * with the packet but specific to the sending device (e.g., an
294 * MSHR). A pointer to this state is returned in the packet's
295 * response so that the sender can quickly look up the state
296 * needed to process it. A specific subclass would be derived
297 * from this to carry state specific to a particular sending
298 * device. */
299 class SenderState {
300 public:
301 virtual ~SenderState() {}
302 };
303
304 /**
305 * Object used to maintain state of a PrintReq. The senderState
306 * field of a PrintReq should always be of this type.
307 */
308 class PrintReqState : public SenderState, public FastAlloc {
309 /** An entry in the label stack. */
310 class LabelStackEntry {
311 public:
312 const std::string label;
313 std::string *prefix;
314 bool labelPrinted;
315 LabelStackEntry(const std::string &_label,
316 std::string *_prefix);
317 };
318
319 typedef std::list<LabelStackEntry> LabelStack;
320 LabelStack labelStack;
321
322 std::string *curPrefixPtr;
323
324 public:
325 std::ostream &os;
326 const int verbosity;
327
328 PrintReqState(std::ostream &os, int verbosity = 0);
329 ~PrintReqState();
330
331 /** Returns the current line prefix. */
332 const std::string &curPrefix() { return *curPrefixPtr; }
333
334 /** Push a label onto the label stack, and prepend the given
335 * prefix string onto the current prefix. Labels will only be
336 * printed if an object within the label's scope is
337 * printed. */
338 void pushLabel(const std::string &lbl,
339 const std::string &prefix = " ");
340 /** Pop a label off the label stack. */
341 void popLabel();
342 /** Print all of the pending unprinted labels on the
343 * stack. Called by printObj(), so normally not called by
344 * users unless bypassing printObj(). */
345 void printLabels();
346 /** Print a Printable object to os, because it matched the
347 * address on a PrintReq. */
348 void printObj(Printable *obj);
349 };
350
351 /** This packet's sender state. Devices should use dynamic_cast<>
352 * to cast to the state appropriate to the sender. */
353 SenderState *senderState;
354
355 /** Return the string name of the cmd field (for debugging and
356 * tracing). */
357 const std::string &cmdString() const { return cmd.toString(); }
358
359 /** Return the index of this command. */
360 inline int cmdToIndex() const { return cmd.toInt(); }
361
362 bool isRead() const { return cmd.isRead(); }
363 bool isWrite() const { return cmd.isWrite(); }
364 bool isRequest() const { return cmd.isRequest(); }
365 bool isResponse() const { return cmd.isResponse(); }
366 bool needsExclusive() const { return cmd.needsExclusive(); }
367 bool needsResponse() const { return cmd.needsResponse(); }
368 bool isInvalidate() const { return cmd.isInvalidate(); }
369 bool hasData() const { return cmd.hasData(); }
370 bool isReadWrite() const { return cmd.isReadWrite(); }
371 bool isLocked() const { return cmd.isLocked(); }
372 bool isError() const { return cmd.isError(); }
373 bool isPrint() const { return cmd.isPrint(); }
374
375 // Snoop flags
376 void assertMemInhibit() { flags[MemInhibit] = true; }
377 bool memInhibitAsserted() { return flags[MemInhibit]; }
378 void assertShared() { flags[Shared] = true; }
379 bool sharedAsserted() { return flags[Shared]; }
380
381 // Special control flags
382 void setExpressSnoop() { flags[ExpressSnoop] = true; }
383 bool isExpressSnoop() { return flags[ExpressSnoop]; }
384 void setSupplyExclusive() { flags[SupplyExclusive] = true; }
385 bool isSupplyExclusive() { return flags[SupplyExclusive]; }
386
387 // Network error conditions... encapsulate them as methods since
388 // their encoding keeps changing (from result field to command
389 // field, etc.)
390 void setNacked() { assert(isResponse()); cmd = MemCmd::NetworkNackError; }
391 void setBadAddress() { assert(isResponse()); cmd = MemCmd::BadAddressError; }
392 bool wasNacked() { return cmd == MemCmd::NetworkNackError; }
393 bool hadBadAddress() { return cmd == MemCmd::BadAddressError; }
394 void copyError(Packet *pkt) { assert(pkt->isError()); cmd = pkt->cmd; }
395
396 bool nic_pkt() { panic("Unimplemented"); M5_DUMMY_RETURN }
397
398 /** Accessor function that returns the source index of the packet. */
399 short getSrc() const { assert(srcValid); return src; }
400 void setSrc(short _src) { src = _src; srcValid = true; }
401 /** Reset source field, e.g. to retransmit packet on different bus. */
402 void clearSrc() { srcValid = false; }
403
404 /** Accessor function that returns the destination index of
405 the packet. */
406 short getDest() const { assert(destValid); return dest; }
407 void setDest(short _dest) { dest = _dest; destValid = true; }
408
409 Addr getAddr() const { assert(addrSizeValid); return addr; }
410 int getSize() const { assert(addrSizeValid); return size; }
411 Addr getOffset(int blkSize) const { return addr & (Addr)(blkSize - 1); }
412
413 /** Constructor. Note that a Request object must be constructed
414 * first, but the Requests's physical address and size fields
415 * need not be valid. The command and destination addresses
416 * must be supplied. */
417 Packet(Request *_req, MemCmd _cmd, short _dest)
418 : cmd(_cmd), req(_req),
419 data(NULL), staticData(false), dynamicData(false), arrayData(false),
420 addr(_req->paddr), size(_req->size), dest(_dest),
421 addrSizeValid(_req->validPaddr), srcValid(false), destValid(true),
422 flags(0), time(curTick), senderState(NULL)
423 {
424 }
425
426 /** Alternate constructor if you are trying to create a packet with
427 * a request that is for a whole block, not the address from the req.
428 * this allows for overriding the size/addr of the req.*/
429 Packet(Request *_req, MemCmd _cmd, short _dest, int _blkSize)
430 : cmd(_cmd), req(_req),
431 data(NULL), staticData(false), dynamicData(false), arrayData(false),
432 addr(_req->paddr & ~(_blkSize - 1)), size(_blkSize), dest(_dest),
433 addrSizeValid(_req->validPaddr), srcValid(false), destValid(true),
434 flags(0), time(curTick), senderState(NULL)
435 {
436 }
437
438 /** Alternate constructor for copying a packet. Copy all fields
439 * *except* if the original packet's data was dynamic, don't copy
440 * that, as we can't guarantee that the new packet's lifetime is
441 * less than that of the original packet. In this case the new
442 * packet should allocate its own data. */
443 Packet(Packet *origPkt, bool clearFlags = false)
444 : cmd(origPkt->cmd), req(origPkt->req),
445 data(origPkt->staticData ? origPkt->data : NULL),
446 staticData(origPkt->staticData),
447 dynamicData(false), arrayData(false),
448 addr(origPkt->addr), size(origPkt->size),
449 src(origPkt->src), dest(origPkt->dest),
450 addrSizeValid(origPkt->addrSizeValid),
451 srcValid(origPkt->srcValid), destValid(origPkt->destValid),
452 flags(clearFlags ? 0 : origPkt->flags),
453 time(curTick), senderState(origPkt->senderState)
454 {
455 }
456
457 /** Destructor. */
458 ~Packet()
459 {
460 // If this is a request packet for which there's no response,
461 // delete the request object here, since the requester will
462 // never get the chance.
463 if (req && isRequest() && !needsResponse())
464 delete req;
465 if (staticData || dynamicData)
466 deleteData();
467 }
468
469 /** Reinitialize packet address and size from the associated
470 * Request object, and reset other fields that may have been
471 * modified by a previous transaction. Typically called when a
472 * statically allocated Request/Packet pair is reused for
473 * multiple transactions. */
474 void reinitFromRequest() {
475 assert(req->validPaddr);
476 flags = 0;
477 addr = req->paddr;
478 size = req->size;
479 time = req->time;
480 addrSizeValid = true;
481 if (dynamicData) {
482 deleteData();
483 dynamicData = false;
484 arrayData = false;
485 }
486 }
487
488 /**
489 * Take a request packet and modify it in place to be suitable for
490 * returning as a response to that request. The source and
491 * destination fields are *not* modified, as is appropriate for
492 * atomic accesses.
493 */
494 void makeResponse()
495 {
496 assert(needsResponse());
497 assert(isRequest());
498 origCmd = cmd;
499 cmd = cmd.responseCommand();
500 dest = src;
501 destValid = srcValid;
502 srcValid = false;
503 }
504
505 void makeAtomicResponse()
506 {
507 makeResponse();
508 }
509
510 void makeTimingResponse()
511 {
512 makeResponse();
513 }
514
515 /**
516 * Take a request packet that has been returned as NACKED and
517 * modify it so that it can be sent out again. Only packets that
518 * need a response can be NACKED, so verify that that is true.

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530 /**
531 * Set the data pointer to the following value that should not be
532 * freed.
533 */
534 template <typename T>
535 void
536 dataStatic(T *p)
537 {
538 if(dynamicData)
539 dynamicData = false;
540 data = (PacketDataPtr)p;
541 staticData = true;
542 }
543
544 /**
545 * Set the data pointer to a value that should have delete []
546 * called on it.
547 */
548 template <typename T>
549 void
550 dataDynamicArray(T *p)
551 {
552 assert(!staticData && !dynamicData);
553 data = (PacketDataPtr)p;
554 dynamicData = true;
555 arrayData = true;
556 }
557
558 /**
559 * set the data pointer to a value that should have delete called
560 * on it.
561 */
562 template <typename T>
563 void
564 dataDynamic(T *p)
565 {
566 assert(!staticData && !dynamicData);
567 data = (PacketDataPtr)p;
568 dynamicData = true;
569 arrayData = false;
570 }
571
572 /** get a pointer to the data ptr. */
573 template <typename T>
574 T*
575 getPtr()
576 {
577 assert(staticData || dynamicData);
578 return (T*)data;
579 }
580
581 /** return the value of what is pointed to in the packet. */
582 template <typename T>
583 T get();
584
585 /** set the value in the data pointer to v. */
586 template <typename T>
587 void set(T v);
588
589 /**
590 * Copy data into the packet from the provided pointer.
591 */
592 void setData(uint8_t *p)
593 {
594 std::memcpy(getPtr<uint8_t>(), p, getSize());
595 }
596
597 /**
598 * Copy data into the packet from the provided block pointer,
599 * which is aligned to the given block size.
600 */
601 void setDataFromBlock(uint8_t *blk_data, int blkSize)
602 {
603 setData(blk_data + getOffset(blkSize));
604 }
605
606 /**
607 * Copy data from the packet to the provided block pointer, which
608 * is aligned to the given block size.
609 */
610 void writeData(uint8_t *p)
611 {
612 std::memcpy(p, getPtr<uint8_t>(), getSize());
613 }
614
615 /**
616 * Copy data from the packet to the memory at the provided pointer.
617 */
618 void writeDataToBlock(uint8_t *blk_data, int blkSize)
619 {
620 writeData(blk_data + getOffset(blkSize));
621 }
622
623 /**
624 * delete the data pointed to in the data pointer. Ok to call to
625 * matter how data was allocted.
626 */
627 void deleteData();
628
629 /** If there isn't data in the packet, allocate some. */
630 void allocate();
631
632 /**
633 * Check a functional request against a memory value represented
634 * by a base/size pair and an associated data array. If the
635 * functional request is a read, it may be satisfied by the memory
636 * value. If the functional request is a write, it may update the
637 * memory value.
638 */
639 bool checkFunctional(Printable *obj, Addr base, int size, uint8_t *data);
640
641 /**
642 * Check a functional request against a memory value stored in
643 * another packet (i.e. an in-transit request or response).
644 */
645 bool checkFunctional(PacketPtr otherPkt) {
646 return checkFunctional(otherPkt,
647 otherPkt->getAddr(), otherPkt->getSize(),
648 otherPkt->hasData() ?
649 otherPkt->getPtr<uint8_t>() : NULL);
650 }
651
652 /**
653 * Push label for PrintReq (safe to call unconditionally).
654 */
655 void pushLabel(const std::string &lbl) {
656 if (isPrint()) {
657 dynamic_cast<PrintReqState*>(senderState)->pushLabel(lbl);
658 }
659 }
660
661 /**
662 * Pop label for PrintReq (safe to call unconditionally).
663 */
664 void popLabel() {
665 if (isPrint()) {
666 dynamic_cast<PrintReqState*>(senderState)->popLabel();
667 }
668 }
669
670 void print(std::ostream &o, int verbosity = 0,
671 const std::string &prefix = "") const;
672};
673
674#endif //__MEM_PACKET_HH