1/*
2 * Copyright (c) 2006 The Regents of The University of Michigan
3 * Copyright (c) 2010 Advanced Micro Devices, Inc.
4 * All rights reserved.
5 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions are
8 * met: redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer;
10 * redistributions in binary form must reproduce the above copyright
11 * notice, this list of conditions and the following disclaimer in the
12 * documentation and/or other materials provided with the distribution;
13 * neither the name of the copyright holders nor the names of its
14 * contributors may be used to endorse or promote products derived from
15 * this software without specific prior written permission.
16 *
17 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
18 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
19 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
20 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
21 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
22 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
23 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
24 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
25 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
26 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
27 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
28 *
29 * Authors: Ron Dreslinski
30 * Steve Reinhardt
31 * Ali Saidi
32 */
33
34/**
35 * @file
36 * Declaration of the Packet class.
37 */
38
39#ifndef __MEM_PACKET_HH__
40#define __MEM_PACKET_HH__
41
42#include <cassert>
43#include <list>
44#include <bitset>
45
46#include "base/cast.hh"
47#include "base/compiler.hh"
48#include "base/fast_alloc.hh"
49#include "base/flags.hh"
50#include "base/misc.hh"
51#include "base/printable.hh"
52#include "base/types.hh"
53#include "mem/request.hh"
54#include "sim/core.hh"
55
56struct Packet;
57typedef Packet *PacketPtr;
58typedef uint8_t* PacketDataPtr;
59typedef std::list<PacketPtr> PacketList;
60
61class MemCmd
62{
63 friend class Packet;
64
65 public:
66 /**
67 * List of all commands associated with a packet.
68 */
69 enum Command
70 {
71 InvalidCmd,
72 ReadReq,
73 ReadResp,
74 ReadRespWithInvalidate,
75 WriteReq,
76 WriteResp,
77 Writeback,
78 SoftPFReq,
79 HardPFReq,
80 SoftPFResp,
81 HardPFResp,
82 WriteInvalidateReq,
83 WriteInvalidateResp,
84 UpgradeReq,
85 SCUpgradeReq, // Special "weak" upgrade for StoreCond
86 UpgradeResp,
87 SCUpgradeFailReq, // Failed SCUpgradeReq in MSHR (never sent)
88 UpgradeFailResp, // Valid for SCUpgradeReq only
89 ReadExReq,
90 ReadExResp,
91 LoadLockedReq,
92 StoreCondReq,
93 StoreCondFailReq, // Failed StoreCondReq in MSHR (never sent)
94 StoreCondResp,
95 SwapReq,
96 SwapResp,
97 MessageReq,
98 MessageResp,
99 // Error responses
100 // @TODO these should be classified as responses rather than
101 // requests; coding them as requests initially for backwards
102 // compatibility
103 NetworkNackError, // nacked at network layer (not by protocol)
104 InvalidDestError, // packet dest field invalid
105 BadAddressError, // memory address invalid
106 // Fake simulator-only commands
107 PrintReq, // Print state matching address
108 NUM_MEM_CMDS
109 };
110
111 private:
112 /**
113 * List of command attributes.
114 */
115 enum Attribute
116 {
117 IsRead, //!< Data flows from responder to requester
118 IsWrite, //!< Data flows from requester to responder
119 IsUpgrade,
120 IsPrefetch, //!< Not a demand access
121 IsInvalidate,
122 NeedsExclusive, //!< Requires exclusive copy to complete in-cache
123 IsRequest, //!< Issued by requester
124 IsResponse, //!< Issue by responder
125 NeedsResponse, //!< Requester needs response from target
126 IsSWPrefetch,
127 IsHWPrefetch,
128 IsLlsc, //!< Alpha/MIPS LL or SC access
129 HasData, //!< There is an associated payload
130 IsError, //!< Error response
131 IsPrint, //!< Print state matching address (for debugging)
132 NUM_COMMAND_ATTRIBUTES
133 };
134
135 /**
136 * Structure that defines attributes and other data associated
137 * with a Command.
138 */
139 struct CommandInfo
140 {
141 /// Set of attribute flags.
142 const std::bitset<NUM_COMMAND_ATTRIBUTES> attributes;
143 /// Corresponding response for requests; InvalidCmd if no
144 /// response is applicable.
145 const Command response;
146 /// String representation (for printing)
147 const std::string str;
148 };
149
150 /// Array to map Command enum to associated info.
151 static const CommandInfo commandInfo[];
152
153 private:
154
155 Command cmd;
156
157 bool
158 testCmdAttrib(MemCmd::Attribute attrib) const
159 {
160 return commandInfo[cmd].attributes[attrib] != 0;
161 }
162
163 public:
164
165 bool isRead() const { return testCmdAttrib(IsRead); }
166 bool isWrite() const { return testCmdAttrib(IsWrite); }
167 bool isUpgrade() const { return testCmdAttrib(IsUpgrade); }
168 bool isRequest() const { return testCmdAttrib(IsRequest); }
169 bool isResponse() const { return testCmdAttrib(IsResponse); }
170 bool needsExclusive() const { return testCmdAttrib(NeedsExclusive); }
171 bool needsResponse() const { return testCmdAttrib(NeedsResponse); }
172 bool isInvalidate() const { return testCmdAttrib(IsInvalidate); }
173 bool hasData() const { return testCmdAttrib(HasData); }
174 bool isReadWrite() const { return isRead() && isWrite(); }
175 bool isLLSC() const { return testCmdAttrib(IsLlsc); }
176 bool isError() const { return testCmdAttrib(IsError); }
177 bool isPrint() const { return testCmdAttrib(IsPrint); }
178
179 const Command
180 responseCommand() const
181 {
182 return commandInfo[cmd].response;
183 }
184
185 /// Return the string to a cmd given by idx.
186 const std::string &toString() const { return commandInfo[cmd].str; }
187 int toInt() const { return (int)cmd; }
188
189 MemCmd(Command _cmd) : cmd(_cmd) { }
190 MemCmd(int _cmd) : cmd((Command)_cmd) { }
191 MemCmd() : cmd(InvalidCmd) { }
192
193 bool operator==(MemCmd c2) const { return (cmd == c2.cmd); }
194 bool operator!=(MemCmd c2) const { return (cmd != c2.cmd); }
195};
196
197/**
198 * A Packet is used to encapsulate a transfer between two objects in
199 * the memory system (e.g., the L1 and L2 cache). (In contrast, a
200 * single Request travels all the way from the requester to the
201 * ultimate destination and back, possibly being conveyed by several
202 * different Packets along the way.)
203 */
204class Packet : public FastAlloc, public Printable
205{
206 public:
207 typedef uint32_t FlagsType;
208 typedef ::Flags<FlagsType> Flags;
209 typedef short NodeID;
210
211 private:
212 static const FlagsType PUBLIC_FLAGS = 0x00000000;
213 static const FlagsType PRIVATE_FLAGS = 0x00007F0F;
214 static const FlagsType COPY_FLAGS = 0x0000000F;
215
216 static const FlagsType SHARED = 0x00000001;
217 // Special control flags
218 /// Special timing-mode atomic snoop for multi-level coherence.
219 static const FlagsType EXPRESS_SNOOP = 0x00000002;
220 /// Does supplier have exclusive copy?
221 /// Useful for multi-level coherence.
222 static const FlagsType SUPPLY_EXCLUSIVE = 0x00000004;
223 // Snoop response flags
224 static const FlagsType MEM_INHIBIT = 0x00000008;
225 /// Are the 'addr' and 'size' fields valid?
226 static const FlagsType VALID_ADDR = 0x00000100;
227 static const FlagsType VALID_SIZE = 0x00000200;
228 /// Is the 'src' field valid?
229 static const FlagsType VALID_SRC = 0x00000400;
230 static const FlagsType VALID_DST = 0x00000800;
231 /// Is the data pointer set to a value that shouldn't be freed
232 /// when the packet is destroyed?
233 static const FlagsType STATIC_DATA = 0x00001000;
234 /// The data pointer points to a value that should be freed when
235 /// the packet is destroyed.
236 static const FlagsType DYNAMIC_DATA = 0x00002000;
237 /// the data pointer points to an array (thus delete []) needs to
238 /// be called on it rather than simply delete.
239 static const FlagsType ARRAY_DATA = 0x00004000;
240
241 Flags flags;
242
243 public:
244 typedef MemCmd::Command Command;
245
246 /// The command field of the packet.
247 MemCmd cmd;
248
249 /// A pointer to the original request.
250 RequestPtr req;
251
252 private:
253 /**
254 * A pointer to the data being transfered. It can be differnt
255 * sizes at each level of the heirarchy so it belongs in the
256 * packet, not request. This may or may not be populated when a
257 * responder recieves the packet. If not populated it memory should
258 * be allocated.
259 */
260 PacketDataPtr data;
261
262 /// The address of the request. This address could be virtual or
263 /// physical, depending on the system configuration.
264 Addr addr;
265
266 /// The size of the request or transfer.
267 unsigned size;
268
269 /**
270 * Device address (e.g., bus ID) of the source of the
271 * transaction. The source is not responsible for setting this
272 * field; it is set implicitly by the interconnect when the packet
273 * is first sent.
274 */
275 NodeID src;
276
277 /**
278 * Device address (e.g., bus ID) of the destination of the
279 * transaction. The special value Broadcast indicates that the
280 * packet should be routed based on its address. This field is
281 * initialized in the constructor and is thus always valid (unlike
282 * addr, size, and src).
283 */
284 NodeID dest;
285
286 /**
287 * The original value of the command field. Only valid when the
288 * current command field is an error condition; in that case, the
289 * previous contents of the command field are copied here. This
290 * field is *not* set on non-error responses.
291 */
292 MemCmd origCmd;
293
294 public:
295 /// Used to calculate latencies for each packet.
296 Tick time;
297
298 /// The time at which the packet will be fully transmitted
299 Tick finishTime;
300
301 /// The time at which the first chunk of the packet will be transmitted
302 Tick firstWordTime;
303
304 /// The special destination address indicating that the packet
305 /// should be routed based on its address.
306 static const NodeID Broadcast = -1;
307
308 /**
309 * A virtual base opaque structure used to hold state associated
310 * with the packet but specific to the sending device (e.g., an
311 * MSHR). A pointer to this state is returned in the packet's
312 * response so that the sender can quickly look up the state
313 * needed to process it. A specific subclass would be derived
314 * from this to carry state specific to a particular sending
315 * device.
316 */
317 struct SenderState
318 {
319 virtual ~SenderState() {}
320 };
321
322 /**
323 * Object used to maintain state of a PrintReq. The senderState
324 * field of a PrintReq should always be of this type.
325 */
326 class PrintReqState : public SenderState, public FastAlloc
327 {
328 private:
329 /**
330 * An entry in the label stack.
331 */
332 struct LabelStackEntry
333 {
334 const std::string label;
335 std::string *prefix;
336 bool labelPrinted;
337 LabelStackEntry(const std::string &_label, std::string *_prefix);
338 };
339
340 typedef std::list<LabelStackEntry> LabelStack;
341 LabelStack labelStack;
342
343 std::string *curPrefixPtr;
344
345 public:
346 std::ostream &os;
347 const int verbosity;
348
349 PrintReqState(std::ostream &os, int verbosity = 0);
350 ~PrintReqState();
351
352 /**
353 * Returns the current line prefix.
354 */
355 const std::string &curPrefix() { return *curPrefixPtr; }
356
357 /**
358 * Push a label onto the label stack, and prepend the given
359 * prefix string onto the current prefix. Labels will only be
360 * printed if an object within the label's scope is printed.
361 */
362 void pushLabel(const std::string &lbl,
363 const std::string &prefix = " ");
364
365 /**
366 * Pop a label off the label stack.
367 */
368 void popLabel();
369
370 /**
371 * Print all of the pending unprinted labels on the
372 * stack. Called by printObj(), so normally not called by
373 * users unless bypassing printObj().
374 */
375 void printLabels();
376
377 /**
378 * Print a Printable object to os, because it matched the
379 * address on a PrintReq.
380 */
381 void printObj(Printable *obj);
382 };
383
384 /**
385 * This packet's sender state. Devices should use dynamic_cast<>
386 * to cast to the state appropriate to the sender. The intent of
387 * this variable is to allow a device to attach extra information
388 * to a request. A response packet must return the sender state
389 * that was attached to the original request (even if a new packet
390 * is created).
391 */
392 SenderState *senderState;
393
394 /// Return the string name of the cmd field (for debugging and
395 /// tracing).
396 const std::string &cmdString() const { return cmd.toString(); }
397
398 /// Return the index of this command.
399 inline int cmdToIndex() const { return cmd.toInt(); }
400
401 bool isRead() const { return cmd.isRead(); }
402 bool isWrite() const { return cmd.isWrite(); }
403 bool isUpgrade() const { return cmd.isUpgrade(); }
404 bool isRequest() const { return cmd.isRequest(); }
405 bool isResponse() const { return cmd.isResponse(); }
406 bool needsExclusive() const { return cmd.needsExclusive(); }
407 bool needsResponse() const { return cmd.needsResponse(); }
408 bool isInvalidate() const { return cmd.isInvalidate(); }
409 bool hasData() const { return cmd.hasData(); }
410 bool isReadWrite() const { return cmd.isReadWrite(); }
411 bool isLLSC() const { return cmd.isLLSC(); }
412 bool isError() const { return cmd.isError(); }
413 bool isPrint() const { return cmd.isPrint(); }
414
415 // Snoop flags
416 void assertMemInhibit() { flags.set(MEM_INHIBIT); }
417 bool memInhibitAsserted() { return flags.isSet(MEM_INHIBIT); }
418 void assertShared() { flags.set(SHARED); }
419 bool sharedAsserted() { return flags.isSet(SHARED); }
420
421 // Special control flags
422 void setExpressSnoop() { flags.set(EXPRESS_SNOOP); }
423 bool isExpressSnoop() { return flags.isSet(EXPRESS_SNOOP); }
424 void setSupplyExclusive() { flags.set(SUPPLY_EXCLUSIVE); }
425 void clearSupplyExclusive() { flags.clear(SUPPLY_EXCLUSIVE); }
426 bool isSupplyExclusive() { return flags.isSet(SUPPLY_EXCLUSIVE); }
427
428 // Network error conditions... encapsulate them as methods since
429 // their encoding keeps changing (from result field to command
430 // field, etc.)
431 void
432 setNacked()
433 {
434 assert(isResponse());
435 cmd = MemCmd::NetworkNackError;
436 }
437
438 void
439 setBadAddress()
440 {
441 assert(isResponse());
442 cmd = MemCmd::BadAddressError;
443 }
444
445 bool wasNacked() const { return cmd == MemCmd::NetworkNackError; }
446 bool hadBadAddress() const { return cmd == MemCmd::BadAddressError; }
447 void copyError(Packet *pkt) { assert(pkt->isError()); cmd = pkt->cmd; }
448
449 bool isSrcValid() { return flags.isSet(VALID_SRC); }
450 /// Accessor function to get the source index of the packet.
451 NodeID getSrc() const { assert(flags.isSet(VALID_SRC)); return src; }
452 /// Accessor function to set the source index of the packet.
453 void setSrc(NodeID _src) { src = _src; flags.set(VALID_SRC); }
454 /// Reset source field, e.g. to retransmit packet on different bus.
455 void clearSrc() { flags.clear(VALID_SRC); }
456
457 bool isDestValid() { return flags.isSet(VALID_DST); }
458 /// Accessor function for the destination index of the packet.
459 NodeID getDest() const { assert(flags.isSet(VALID_DST)); return dest; }
460 /// Accessor function to set the destination index of the packet.
461 void setDest(NodeID _dest) { dest = _dest; flags.set(VALID_DST); }
462
463 Addr getAddr() const { assert(flags.isSet(VALID_ADDR)); return addr; }
464 unsigned getSize() const { assert(flags.isSet(VALID_SIZE)); return size; }
465 Addr getOffset(int blkSize) const { return getAddr() & (Addr)(blkSize - 1); }
466
467 /**
468 * It has been determined that the SC packet should successfully update
469 * memory. Therefore, convert this SC packet to a normal write.
470 */
471 void
472 convertScToWrite()
473 {
474 assert(isLLSC());
475 assert(isWrite());
476 cmd = MemCmd::WriteReq;
477 }
478
479 /**
480 * When ruby is in use, Ruby will monitor the cache line and thus M5
481 * phys memory should treat LL ops as normal reads.
482 */
483 void
484 convertLlToRead()
485 {
486 assert(isLLSC());
487 assert(isRead());
488 cmd = MemCmd::ReadReq;
489 }
490
491 /**
492 * Constructor. Note that a Request object must be constructed
493 * first, but the Requests's physical address and size fields need
494 * not be valid. The command and destination addresses must be
495 * supplied.
496 */
497 Packet(Request *_req, MemCmd _cmd, NodeID _dest)
498 : flags(VALID_DST), cmd(_cmd), req(_req), data(NULL),
499 dest(_dest), time(curTick), senderState(NULL)
500 {
501 if (req->hasPaddr()) {
502 addr = req->getPaddr();
503 flags.set(VALID_ADDR);
504 }
505 if (req->hasSize()) {
506 size = req->getSize();
507 flags.set(VALID_SIZE);
508 }
509 }
510
511 /**
512 * Alternate constructor if you are trying to create a packet with
513 * a request that is for a whole block, not the address from the
514 * req. this allows for overriding the size/addr of the req.
515 */
516 Packet(Request *_req, MemCmd _cmd, NodeID _dest, int _blkSize)
517 : flags(VALID_DST), cmd(_cmd), req(_req), data(NULL),
518 dest(_dest), time(curTick), senderState(NULL)
519 {
520 if (req->hasPaddr()) {
521 addr = req->getPaddr() & ~(_blkSize - 1);
522 flags.set(VALID_ADDR);
523 }
524 size = _blkSize;
525 flags.set(VALID_SIZE);
526 }
527
528 /**
529 * Alternate constructor for copying a packet. Copy all fields
530 * *except* if the original packet's data was dynamic, don't copy
531 * that, as we can't guarantee that the new packet's lifetime is
532 * less than that of the original packet. In this case the new
533 * packet should allocate its own data.
534 */
535 Packet(Packet *pkt, bool clearFlags = false)
536 : cmd(pkt->cmd), req(pkt->req),
537 data(pkt->flags.isSet(STATIC_DATA) ? pkt->data : NULL),
538 addr(pkt->addr), size(pkt->size), src(pkt->src), dest(pkt->dest),
539 time(curTick), senderState(pkt->senderState)
540 {
541 if (!clearFlags)
542 flags.set(pkt->flags & COPY_FLAGS);
543
544 flags.set(pkt->flags & (VALID_ADDR|VALID_SIZE|VALID_SRC|VALID_DST));
545 flags.set(pkt->flags & STATIC_DATA);
546 }
547
548 /**
549 * clean up packet variables
550 */
551 ~Packet()
552 {
553 // If this is a request packet for which there's no response,
554 // delete the request object here, since the requester will
555 // never get the chance.
556 if (req && isRequest() && !needsResponse())
557 delete req;
558 deleteData();
559 }
560
561 /**
562 * Reinitialize packet address and size from the associated
563 * Request object, and reset other fields that may have been
564 * modified by a previous transaction. Typically called when a
565 * statically allocated Request/Packet pair is reused for multiple
566 * transactions.
567 */
568 void
569 reinitFromRequest()
570 {
571 assert(req->hasPaddr());
572 flags = 0;
573 addr = req->getPaddr();
574 size = req->getSize();
575 time = req->time();
576
577 flags.set(VALID_ADDR|VALID_SIZE);
578 deleteData();
579 }
580
581 /**
582 * Take a request packet and modify it in place to be suitable for
583 * returning as a response to that request. The source and
584 * destination fields are *not* modified, as is appropriate for
585 * atomic accesses.
586 */
587 void
588 makeResponse()
589 {
590 assert(needsResponse());
591 assert(isRequest());
592 origCmd = cmd;
593 cmd = cmd.responseCommand();
594
595 // responses are never express, even if the snoop that
596 // triggered them was
597 flags.clear(EXPRESS_SNOOP);
598
599 dest = src;
600 flags.set(VALID_DST, flags.isSet(VALID_SRC));
601 flags.clear(VALID_SRC);
602 }
603
604 void
605 makeAtomicResponse()
606 {
607 makeResponse();
608 }
609
610 void
611 makeTimingResponse()
612 {
613 makeResponse();
614 }
615
616 /**
617 * Take a request packet that has been returned as NACKED and
618 * modify it so that it can be sent out again. Only packets that
619 * need a response can be NACKED, so verify that that is true.
620 */
621 void
622 reinitNacked()
623 {
624 assert(wasNacked());
625 cmd = origCmd;
626 assert(needsResponse());
627 setDest(Broadcast);
628 }
629
630 void
631 setSize(unsigned size)
632 {
633 assert(!flags.isSet(VALID_SIZE));
634
635 this->size = size;
636 flags.set(VALID_SIZE);
637 }
638
639
640 /**
641 * Set the data pointer to the following value that should not be
642 * freed.
643 */
644 template <typename T>
645 void
646 dataStatic(T *p)
647 {
648 assert(flags.noneSet(STATIC_DATA|DYNAMIC_DATA|ARRAY_DATA));
649 data = (PacketDataPtr)p;
650 flags.set(STATIC_DATA);
651 }
652
653 /**
654 * Set the data pointer to a value that should have delete []
655 * called on it.
656 */
657 template <typename T>
658 void
659 dataDynamicArray(T *p)
660 {
661 assert(flags.noneSet(STATIC_DATA|DYNAMIC_DATA|ARRAY_DATA));
662 data = (PacketDataPtr)p;
663 flags.set(DYNAMIC_DATA|ARRAY_DATA);
664 }
665
666 /**
667 * set the data pointer to a value that should have delete called
668 * on it.
669 */
670 template <typename T>
671 void
672 dataDynamic(T *p)
673 {
674 assert(flags.noneSet(STATIC_DATA|DYNAMIC_DATA|ARRAY_DATA));
675 data = (PacketDataPtr)p;
676 flags.set(DYNAMIC_DATA);
677 }
678
679 /**
680 * get a pointer to the data ptr.
681 */
682 template <typename T>
683 T*
684 getPtr()
685 {
686 assert(flags.isSet(STATIC_DATA|DYNAMIC_DATA));
687 return (T*)data;
688 }
689
690 /**
691 * return the value of what is pointed to in the packet.
692 */
693 template <typename T>
694 T get();
695
696 /**
697 * set the value in the data pointer to v.
698 */
699 template <typename T>
700 void set(T v);
701
702 /**
703 * Copy data into the packet from the provided pointer.
704 */
705 void
706 setData(uint8_t *p)
707 {
| 1/*
2 * Copyright (c) 2006 The Regents of The University of Michigan
3 * Copyright (c) 2010 Advanced Micro Devices, Inc.
4 * All rights reserved.
5 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions are
8 * met: redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer;
10 * redistributions in binary form must reproduce the above copyright
11 * notice, this list of conditions and the following disclaimer in the
12 * documentation and/or other materials provided with the distribution;
13 * neither the name of the copyright holders nor the names of its
14 * contributors may be used to endorse or promote products derived from
15 * this software without specific prior written permission.
16 *
17 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
18 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
19 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
20 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
21 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
22 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
23 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
24 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
25 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
26 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
27 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
28 *
29 * Authors: Ron Dreslinski
30 * Steve Reinhardt
31 * Ali Saidi
32 */
33
34/**
35 * @file
36 * Declaration of the Packet class.
37 */
38
39#ifndef __MEM_PACKET_HH__
40#define __MEM_PACKET_HH__
41
42#include <cassert>
43#include <list>
44#include <bitset>
45
46#include "base/cast.hh"
47#include "base/compiler.hh"
48#include "base/fast_alloc.hh"
49#include "base/flags.hh"
50#include "base/misc.hh"
51#include "base/printable.hh"
52#include "base/types.hh"
53#include "mem/request.hh"
54#include "sim/core.hh"
55
56struct Packet;
57typedef Packet *PacketPtr;
58typedef uint8_t* PacketDataPtr;
59typedef std::list<PacketPtr> PacketList;
60
61class MemCmd
62{
63 friend class Packet;
64
65 public:
66 /**
67 * List of all commands associated with a packet.
68 */
69 enum Command
70 {
71 InvalidCmd,
72 ReadReq,
73 ReadResp,
74 ReadRespWithInvalidate,
75 WriteReq,
76 WriteResp,
77 Writeback,
78 SoftPFReq,
79 HardPFReq,
80 SoftPFResp,
81 HardPFResp,
82 WriteInvalidateReq,
83 WriteInvalidateResp,
84 UpgradeReq,
85 SCUpgradeReq, // Special "weak" upgrade for StoreCond
86 UpgradeResp,
87 SCUpgradeFailReq, // Failed SCUpgradeReq in MSHR (never sent)
88 UpgradeFailResp, // Valid for SCUpgradeReq only
89 ReadExReq,
90 ReadExResp,
91 LoadLockedReq,
92 StoreCondReq,
93 StoreCondFailReq, // Failed StoreCondReq in MSHR (never sent)
94 StoreCondResp,
95 SwapReq,
96 SwapResp,
97 MessageReq,
98 MessageResp,
99 // Error responses
100 // @TODO these should be classified as responses rather than
101 // requests; coding them as requests initially for backwards
102 // compatibility
103 NetworkNackError, // nacked at network layer (not by protocol)
104 InvalidDestError, // packet dest field invalid
105 BadAddressError, // memory address invalid
106 // Fake simulator-only commands
107 PrintReq, // Print state matching address
108 NUM_MEM_CMDS
109 };
110
111 private:
112 /**
113 * List of command attributes.
114 */
115 enum Attribute
116 {
117 IsRead, //!< Data flows from responder to requester
118 IsWrite, //!< Data flows from requester to responder
119 IsUpgrade,
120 IsPrefetch, //!< Not a demand access
121 IsInvalidate,
122 NeedsExclusive, //!< Requires exclusive copy to complete in-cache
123 IsRequest, //!< Issued by requester
124 IsResponse, //!< Issue by responder
125 NeedsResponse, //!< Requester needs response from target
126 IsSWPrefetch,
127 IsHWPrefetch,
128 IsLlsc, //!< Alpha/MIPS LL or SC access
129 HasData, //!< There is an associated payload
130 IsError, //!< Error response
131 IsPrint, //!< Print state matching address (for debugging)
132 NUM_COMMAND_ATTRIBUTES
133 };
134
135 /**
136 * Structure that defines attributes and other data associated
137 * with a Command.
138 */
139 struct CommandInfo
140 {
141 /// Set of attribute flags.
142 const std::bitset<NUM_COMMAND_ATTRIBUTES> attributes;
143 /// Corresponding response for requests; InvalidCmd if no
144 /// response is applicable.
145 const Command response;
146 /// String representation (for printing)
147 const std::string str;
148 };
149
150 /// Array to map Command enum to associated info.
151 static const CommandInfo commandInfo[];
152
153 private:
154
155 Command cmd;
156
157 bool
158 testCmdAttrib(MemCmd::Attribute attrib) const
159 {
160 return commandInfo[cmd].attributes[attrib] != 0;
161 }
162
163 public:
164
165 bool isRead() const { return testCmdAttrib(IsRead); }
166 bool isWrite() const { return testCmdAttrib(IsWrite); }
167 bool isUpgrade() const { return testCmdAttrib(IsUpgrade); }
168 bool isRequest() const { return testCmdAttrib(IsRequest); }
169 bool isResponse() const { return testCmdAttrib(IsResponse); }
170 bool needsExclusive() const { return testCmdAttrib(NeedsExclusive); }
171 bool needsResponse() const { return testCmdAttrib(NeedsResponse); }
172 bool isInvalidate() const { return testCmdAttrib(IsInvalidate); }
173 bool hasData() const { return testCmdAttrib(HasData); }
174 bool isReadWrite() const { return isRead() && isWrite(); }
175 bool isLLSC() const { return testCmdAttrib(IsLlsc); }
176 bool isError() const { return testCmdAttrib(IsError); }
177 bool isPrint() const { return testCmdAttrib(IsPrint); }
178
179 const Command
180 responseCommand() const
181 {
182 return commandInfo[cmd].response;
183 }
184
185 /// Return the string to a cmd given by idx.
186 const std::string &toString() const { return commandInfo[cmd].str; }
187 int toInt() const { return (int)cmd; }
188
189 MemCmd(Command _cmd) : cmd(_cmd) { }
190 MemCmd(int _cmd) : cmd((Command)_cmd) { }
191 MemCmd() : cmd(InvalidCmd) { }
192
193 bool operator==(MemCmd c2) const { return (cmd == c2.cmd); }
194 bool operator!=(MemCmd c2) const { return (cmd != c2.cmd); }
195};
196
197/**
198 * A Packet is used to encapsulate a transfer between two objects in
199 * the memory system (e.g., the L1 and L2 cache). (In contrast, a
200 * single Request travels all the way from the requester to the
201 * ultimate destination and back, possibly being conveyed by several
202 * different Packets along the way.)
203 */
204class Packet : public FastAlloc, public Printable
205{
206 public:
207 typedef uint32_t FlagsType;
208 typedef ::Flags<FlagsType> Flags;
209 typedef short NodeID;
210
211 private:
212 static const FlagsType PUBLIC_FLAGS = 0x00000000;
213 static const FlagsType PRIVATE_FLAGS = 0x00007F0F;
214 static const FlagsType COPY_FLAGS = 0x0000000F;
215
216 static const FlagsType SHARED = 0x00000001;
217 // Special control flags
218 /// Special timing-mode atomic snoop for multi-level coherence.
219 static const FlagsType EXPRESS_SNOOP = 0x00000002;
220 /// Does supplier have exclusive copy?
221 /// Useful for multi-level coherence.
222 static const FlagsType SUPPLY_EXCLUSIVE = 0x00000004;
223 // Snoop response flags
224 static const FlagsType MEM_INHIBIT = 0x00000008;
225 /// Are the 'addr' and 'size' fields valid?
226 static const FlagsType VALID_ADDR = 0x00000100;
227 static const FlagsType VALID_SIZE = 0x00000200;
228 /// Is the 'src' field valid?
229 static const FlagsType VALID_SRC = 0x00000400;
230 static const FlagsType VALID_DST = 0x00000800;
231 /// Is the data pointer set to a value that shouldn't be freed
232 /// when the packet is destroyed?
233 static const FlagsType STATIC_DATA = 0x00001000;
234 /// The data pointer points to a value that should be freed when
235 /// the packet is destroyed.
236 static const FlagsType DYNAMIC_DATA = 0x00002000;
237 /// the data pointer points to an array (thus delete []) needs to
238 /// be called on it rather than simply delete.
239 static const FlagsType ARRAY_DATA = 0x00004000;
240
241 Flags flags;
242
243 public:
244 typedef MemCmd::Command Command;
245
246 /// The command field of the packet.
247 MemCmd cmd;
248
249 /// A pointer to the original request.
250 RequestPtr req;
251
252 private:
253 /**
254 * A pointer to the data being transfered. It can be differnt
255 * sizes at each level of the heirarchy so it belongs in the
256 * packet, not request. This may or may not be populated when a
257 * responder recieves the packet. If not populated it memory should
258 * be allocated.
259 */
260 PacketDataPtr data;
261
262 /// The address of the request. This address could be virtual or
263 /// physical, depending on the system configuration.
264 Addr addr;
265
266 /// The size of the request or transfer.
267 unsigned size;
268
269 /**
270 * Device address (e.g., bus ID) of the source of the
271 * transaction. The source is not responsible for setting this
272 * field; it is set implicitly by the interconnect when the packet
273 * is first sent.
274 */
275 NodeID src;
276
277 /**
278 * Device address (e.g., bus ID) of the destination of the
279 * transaction. The special value Broadcast indicates that the
280 * packet should be routed based on its address. This field is
281 * initialized in the constructor and is thus always valid (unlike
282 * addr, size, and src).
283 */
284 NodeID dest;
285
286 /**
287 * The original value of the command field. Only valid when the
288 * current command field is an error condition; in that case, the
289 * previous contents of the command field are copied here. This
290 * field is *not* set on non-error responses.
291 */
292 MemCmd origCmd;
293
294 public:
295 /// Used to calculate latencies for each packet.
296 Tick time;
297
298 /// The time at which the packet will be fully transmitted
299 Tick finishTime;
300
301 /// The time at which the first chunk of the packet will be transmitted
302 Tick firstWordTime;
303
304 /// The special destination address indicating that the packet
305 /// should be routed based on its address.
306 static const NodeID Broadcast = -1;
307
308 /**
309 * A virtual base opaque structure used to hold state associated
310 * with the packet but specific to the sending device (e.g., an
311 * MSHR). A pointer to this state is returned in the packet's
312 * response so that the sender can quickly look up the state
313 * needed to process it. A specific subclass would be derived
314 * from this to carry state specific to a particular sending
315 * device.
316 */
317 struct SenderState
318 {
319 virtual ~SenderState() {}
320 };
321
322 /**
323 * Object used to maintain state of a PrintReq. The senderState
324 * field of a PrintReq should always be of this type.
325 */
326 class PrintReqState : public SenderState, public FastAlloc
327 {
328 private:
329 /**
330 * An entry in the label stack.
331 */
332 struct LabelStackEntry
333 {
334 const std::string label;
335 std::string *prefix;
336 bool labelPrinted;
337 LabelStackEntry(const std::string &_label, std::string *_prefix);
338 };
339
340 typedef std::list<LabelStackEntry> LabelStack;
341 LabelStack labelStack;
342
343 std::string *curPrefixPtr;
344
345 public:
346 std::ostream &os;
347 const int verbosity;
348
349 PrintReqState(std::ostream &os, int verbosity = 0);
350 ~PrintReqState();
351
352 /**
353 * Returns the current line prefix.
354 */
355 const std::string &curPrefix() { return *curPrefixPtr; }
356
357 /**
358 * Push a label onto the label stack, and prepend the given
359 * prefix string onto the current prefix. Labels will only be
360 * printed if an object within the label's scope is printed.
361 */
362 void pushLabel(const std::string &lbl,
363 const std::string &prefix = " ");
364
365 /**
366 * Pop a label off the label stack.
367 */
368 void popLabel();
369
370 /**
371 * Print all of the pending unprinted labels on the
372 * stack. Called by printObj(), so normally not called by
373 * users unless bypassing printObj().
374 */
375 void printLabels();
376
377 /**
378 * Print a Printable object to os, because it matched the
379 * address on a PrintReq.
380 */
381 void printObj(Printable *obj);
382 };
383
384 /**
385 * This packet's sender state. Devices should use dynamic_cast<>
386 * to cast to the state appropriate to the sender. The intent of
387 * this variable is to allow a device to attach extra information
388 * to a request. A response packet must return the sender state
389 * that was attached to the original request (even if a new packet
390 * is created).
391 */
392 SenderState *senderState;
393
394 /// Return the string name of the cmd field (for debugging and
395 /// tracing).
396 const std::string &cmdString() const { return cmd.toString(); }
397
398 /// Return the index of this command.
399 inline int cmdToIndex() const { return cmd.toInt(); }
400
401 bool isRead() const { return cmd.isRead(); }
402 bool isWrite() const { return cmd.isWrite(); }
403 bool isUpgrade() const { return cmd.isUpgrade(); }
404 bool isRequest() const { return cmd.isRequest(); }
405 bool isResponse() const { return cmd.isResponse(); }
406 bool needsExclusive() const { return cmd.needsExclusive(); }
407 bool needsResponse() const { return cmd.needsResponse(); }
408 bool isInvalidate() const { return cmd.isInvalidate(); }
409 bool hasData() const { return cmd.hasData(); }
410 bool isReadWrite() const { return cmd.isReadWrite(); }
411 bool isLLSC() const { return cmd.isLLSC(); }
412 bool isError() const { return cmd.isError(); }
413 bool isPrint() const { return cmd.isPrint(); }
414
415 // Snoop flags
416 void assertMemInhibit() { flags.set(MEM_INHIBIT); }
417 bool memInhibitAsserted() { return flags.isSet(MEM_INHIBIT); }
418 void assertShared() { flags.set(SHARED); }
419 bool sharedAsserted() { return flags.isSet(SHARED); }
420
421 // Special control flags
422 void setExpressSnoop() { flags.set(EXPRESS_SNOOP); }
423 bool isExpressSnoop() { return flags.isSet(EXPRESS_SNOOP); }
424 void setSupplyExclusive() { flags.set(SUPPLY_EXCLUSIVE); }
425 void clearSupplyExclusive() { flags.clear(SUPPLY_EXCLUSIVE); }
426 bool isSupplyExclusive() { return flags.isSet(SUPPLY_EXCLUSIVE); }
427
428 // Network error conditions... encapsulate them as methods since
429 // their encoding keeps changing (from result field to command
430 // field, etc.)
431 void
432 setNacked()
433 {
434 assert(isResponse());
435 cmd = MemCmd::NetworkNackError;
436 }
437
438 void
439 setBadAddress()
440 {
441 assert(isResponse());
442 cmd = MemCmd::BadAddressError;
443 }
444
445 bool wasNacked() const { return cmd == MemCmd::NetworkNackError; }
446 bool hadBadAddress() const { return cmd == MemCmd::BadAddressError; }
447 void copyError(Packet *pkt) { assert(pkt->isError()); cmd = pkt->cmd; }
448
449 bool isSrcValid() { return flags.isSet(VALID_SRC); }
450 /// Accessor function to get the source index of the packet.
451 NodeID getSrc() const { assert(flags.isSet(VALID_SRC)); return src; }
452 /// Accessor function to set the source index of the packet.
453 void setSrc(NodeID _src) { src = _src; flags.set(VALID_SRC); }
454 /// Reset source field, e.g. to retransmit packet on different bus.
455 void clearSrc() { flags.clear(VALID_SRC); }
456
457 bool isDestValid() { return flags.isSet(VALID_DST); }
458 /// Accessor function for the destination index of the packet.
459 NodeID getDest() const { assert(flags.isSet(VALID_DST)); return dest; }
460 /// Accessor function to set the destination index of the packet.
461 void setDest(NodeID _dest) { dest = _dest; flags.set(VALID_DST); }
462
463 Addr getAddr() const { assert(flags.isSet(VALID_ADDR)); return addr; }
464 unsigned getSize() const { assert(flags.isSet(VALID_SIZE)); return size; }
465 Addr getOffset(int blkSize) const { return getAddr() & (Addr)(blkSize - 1); }
466
467 /**
468 * It has been determined that the SC packet should successfully update
469 * memory. Therefore, convert this SC packet to a normal write.
470 */
471 void
472 convertScToWrite()
473 {
474 assert(isLLSC());
475 assert(isWrite());
476 cmd = MemCmd::WriteReq;
477 }
478
479 /**
480 * When ruby is in use, Ruby will monitor the cache line and thus M5
481 * phys memory should treat LL ops as normal reads.
482 */
483 void
484 convertLlToRead()
485 {
486 assert(isLLSC());
487 assert(isRead());
488 cmd = MemCmd::ReadReq;
489 }
490
491 /**
492 * Constructor. Note that a Request object must be constructed
493 * first, but the Requests's physical address and size fields need
494 * not be valid. The command and destination addresses must be
495 * supplied.
496 */
497 Packet(Request *_req, MemCmd _cmd, NodeID _dest)
498 : flags(VALID_DST), cmd(_cmd), req(_req), data(NULL),
499 dest(_dest), time(curTick), senderState(NULL)
500 {
501 if (req->hasPaddr()) {
502 addr = req->getPaddr();
503 flags.set(VALID_ADDR);
504 }
505 if (req->hasSize()) {
506 size = req->getSize();
507 flags.set(VALID_SIZE);
508 }
509 }
510
511 /**
512 * Alternate constructor if you are trying to create a packet with
513 * a request that is for a whole block, not the address from the
514 * req. this allows for overriding the size/addr of the req.
515 */
516 Packet(Request *_req, MemCmd _cmd, NodeID _dest, int _blkSize)
517 : flags(VALID_DST), cmd(_cmd), req(_req), data(NULL),
518 dest(_dest), time(curTick), senderState(NULL)
519 {
520 if (req->hasPaddr()) {
521 addr = req->getPaddr() & ~(_blkSize - 1);
522 flags.set(VALID_ADDR);
523 }
524 size = _blkSize;
525 flags.set(VALID_SIZE);
526 }
527
528 /**
529 * Alternate constructor for copying a packet. Copy all fields
530 * *except* if the original packet's data was dynamic, don't copy
531 * that, as we can't guarantee that the new packet's lifetime is
532 * less than that of the original packet. In this case the new
533 * packet should allocate its own data.
534 */
535 Packet(Packet *pkt, bool clearFlags = false)
536 : cmd(pkt->cmd), req(pkt->req),
537 data(pkt->flags.isSet(STATIC_DATA) ? pkt->data : NULL),
538 addr(pkt->addr), size(pkt->size), src(pkt->src), dest(pkt->dest),
539 time(curTick), senderState(pkt->senderState)
540 {
541 if (!clearFlags)
542 flags.set(pkt->flags & COPY_FLAGS);
543
544 flags.set(pkt->flags & (VALID_ADDR|VALID_SIZE|VALID_SRC|VALID_DST));
545 flags.set(pkt->flags & STATIC_DATA);
546 }
547
548 /**
549 * clean up packet variables
550 */
551 ~Packet()
552 {
553 // If this is a request packet for which there's no response,
554 // delete the request object here, since the requester will
555 // never get the chance.
556 if (req && isRequest() && !needsResponse())
557 delete req;
558 deleteData();
559 }
560
561 /**
562 * Reinitialize packet address and size from the associated
563 * Request object, and reset other fields that may have been
564 * modified by a previous transaction. Typically called when a
565 * statically allocated Request/Packet pair is reused for multiple
566 * transactions.
567 */
568 void
569 reinitFromRequest()
570 {
571 assert(req->hasPaddr());
572 flags = 0;
573 addr = req->getPaddr();
574 size = req->getSize();
575 time = req->time();
576
577 flags.set(VALID_ADDR|VALID_SIZE);
578 deleteData();
579 }
580
581 /**
582 * Take a request packet and modify it in place to be suitable for
583 * returning as a response to that request. The source and
584 * destination fields are *not* modified, as is appropriate for
585 * atomic accesses.
586 */
587 void
588 makeResponse()
589 {
590 assert(needsResponse());
591 assert(isRequest());
592 origCmd = cmd;
593 cmd = cmd.responseCommand();
594
595 // responses are never express, even if the snoop that
596 // triggered them was
597 flags.clear(EXPRESS_SNOOP);
598
599 dest = src;
600 flags.set(VALID_DST, flags.isSet(VALID_SRC));
601 flags.clear(VALID_SRC);
602 }
603
604 void
605 makeAtomicResponse()
606 {
607 makeResponse();
608 }
609
610 void
611 makeTimingResponse()
612 {
613 makeResponse();
614 }
615
616 /**
617 * Take a request packet that has been returned as NACKED and
618 * modify it so that it can be sent out again. Only packets that
619 * need a response can be NACKED, so verify that that is true.
620 */
621 void
622 reinitNacked()
623 {
624 assert(wasNacked());
625 cmd = origCmd;
626 assert(needsResponse());
627 setDest(Broadcast);
628 }
629
630 void
631 setSize(unsigned size)
632 {
633 assert(!flags.isSet(VALID_SIZE));
634
635 this->size = size;
636 flags.set(VALID_SIZE);
637 }
638
639
640 /**
641 * Set the data pointer to the following value that should not be
642 * freed.
643 */
644 template <typename T>
645 void
646 dataStatic(T *p)
647 {
648 assert(flags.noneSet(STATIC_DATA|DYNAMIC_DATA|ARRAY_DATA));
649 data = (PacketDataPtr)p;
650 flags.set(STATIC_DATA);
651 }
652
653 /**
654 * Set the data pointer to a value that should have delete []
655 * called on it.
656 */
657 template <typename T>
658 void
659 dataDynamicArray(T *p)
660 {
661 assert(flags.noneSet(STATIC_DATA|DYNAMIC_DATA|ARRAY_DATA));
662 data = (PacketDataPtr)p;
663 flags.set(DYNAMIC_DATA|ARRAY_DATA);
664 }
665
666 /**
667 * set the data pointer to a value that should have delete called
668 * on it.
669 */
670 template <typename T>
671 void
672 dataDynamic(T *p)
673 {
674 assert(flags.noneSet(STATIC_DATA|DYNAMIC_DATA|ARRAY_DATA));
675 data = (PacketDataPtr)p;
676 flags.set(DYNAMIC_DATA);
677 }
678
679 /**
680 * get a pointer to the data ptr.
681 */
682 template <typename T>
683 T*
684 getPtr()
685 {
686 assert(flags.isSet(STATIC_DATA|DYNAMIC_DATA));
687 return (T*)data;
688 }
689
690 /**
691 * return the value of what is pointed to in the packet.
692 */
693 template <typename T>
694 T get();
695
696 /**
697 * set the value in the data pointer to v.
698 */
699 template <typename T>
700 void set(T v);
701
702 /**
703 * Copy data into the packet from the provided pointer.
704 */
705 void
706 setData(uint8_t *p)
707 {
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