1/*
2 * Copyright (c) 2012-2018 ARM Limited
3 * All rights reserved
4 *
5 * The license below extends only to copyright in the software and shall
6 * not be construed as granting a license to any other intellectual
7 * property including but not limited to intellectual property relating
8 * to a hardware implementation of the functionality of the software
9 * licensed hereunder. You may use the software subject to the license
10 * terms below provided that you ensure that this notice is replicated
11 * unmodified and in its entirety in all distributions of the software,
12 * modified or unmodified, in source code or in binary form.
13 *
14 * Copyright (c) 2006 The Regents of The University of Michigan
15 * Copyright (c) 2010,2015 Advanced Micro Devices, Inc.
16 * All rights reserved.
17 *
18 * Redistribution and use in source and binary forms, with or without
19 * modification, are permitted provided that the following conditions are
20 * met: redistributions of source code must retain the above copyright
21 * notice, this list of conditions and the following disclaimer;
22 * redistributions in binary form must reproduce the above copyright
23 * notice, this list of conditions and the following disclaimer in the
24 * documentation and/or other materials provided with the distribution;
25 * neither the name of the copyright holders nor the names of its
26 * contributors may be used to endorse or promote products derived from
27 * this software without specific prior written permission.
28 *
29 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
30 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
31 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
32 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
33 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
34 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
35 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
36 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
37 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
38 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
39 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
40 *
41 * Authors: Ron Dreslinski
42 * Steve Reinhardt
43 * Ali Saidi
44 * Andreas Hansson
45 * Nikos Nikoleris
46 */
47
48/**
49 * @file
50 * Declaration of the Packet class.
51 */
52
53#ifndef __MEM_PACKET_HH__
54#define __MEM_PACKET_HH__
55
56#include <bitset>
57#include <cassert>
58#include <list>
59
60#include "base/cast.hh"
61#include "base/compiler.hh"
62#include "base/flags.hh"
63#include "base/logging.hh"
64#include "base/printable.hh"
65#include "base/types.hh"
66#include "config/the_isa.hh"
67#include "mem/request.hh"
68#include "sim/core.hh"
69
70class Packet;
71typedef Packet *PacketPtr;
72typedef uint8_t* PacketDataPtr;
73typedef std::list<PacketPtr> PacketList;
74typedef uint64_t PacketId;
75
76class MemCmd
77{
78 friend class Packet;
79
80 public:
81 /**
82 * List of all commands associated with a packet.
83 */
84 enum Command
85 {
86 InvalidCmd,
87 ReadReq,
88 ReadResp,
89 ReadRespWithInvalidate,
90 WriteReq,
91 WriteResp,
92 WritebackDirty,
93 WritebackClean,
94 WriteClean, // writes dirty data below without evicting
95 CleanEvict,
96 SoftPFReq,
97 HardPFReq,
98 SoftPFResp,
99 HardPFResp,
100 WriteLineReq,
101 UpgradeReq,
102 SCUpgradeReq, // Special "weak" upgrade for StoreCond
103 UpgradeResp,
104 SCUpgradeFailReq, // Failed SCUpgradeReq in MSHR (never sent)
105 UpgradeFailResp, // Valid for SCUpgradeReq only
106 ReadExReq,
107 ReadExResp,
108 ReadCleanReq,
109 ReadSharedReq,
110 LoadLockedReq,
111 StoreCondReq,
112 StoreCondFailReq, // Failed StoreCondReq in MSHR (never sent)
113 StoreCondResp,
114 SwapReq,
115 SwapResp,
116 MessageReq,
117 MessageResp,
118 MemFenceReq,
119 MemFenceResp,
120 CleanSharedReq,
121 CleanSharedResp,
122 CleanInvalidReq,
123 CleanInvalidResp,
124 // Error responses
125 // @TODO these should be classified as responses rather than
126 // requests; coding them as requests initially for backwards
127 // compatibility
128 InvalidDestError, // packet dest field invalid
129 BadAddressError, // memory address invalid
130 FunctionalReadError, // unable to fulfill functional read
131 FunctionalWriteError, // unable to fulfill functional write
132 // Fake simulator-only commands
133 PrintReq, // Print state matching address
134 FlushReq, //request for a cache flush
135 InvalidateReq, // request for address to be invalidated
136 InvalidateResp,
137 NUM_MEM_CMDS
138 };
139
140 private:
141 /**
142 * List of command attributes.
143 */
144 enum Attribute
145 {
146 IsRead, //!< Data flows from responder to requester
147 IsWrite, //!< Data flows from requester to responder
148 IsUpgrade,
149 IsInvalidate,
150 IsClean, //!< Cleans any existing dirty blocks
151 NeedsWritable, //!< Requires writable copy to complete in-cache
152 IsRequest, //!< Issued by requester
153 IsResponse, //!< Issue by responder
154 NeedsResponse, //!< Requester needs response from target
155 IsEviction,
156 IsSWPrefetch,
157 IsHWPrefetch,
158 IsLlsc, //!< Alpha/MIPS LL or SC access
159 HasData, //!< There is an associated payload
160 IsError, //!< Error response
161 IsPrint, //!< Print state matching address (for debugging)
162 IsFlush, //!< Flush the address from caches
163 FromCache, //!< Request originated from a caching agent
164 NUM_COMMAND_ATTRIBUTES
165 };
166
167 /**
168 * Structure that defines attributes and other data associated
169 * with a Command.
170 */
171 struct CommandInfo
172 {
173 /// Set of attribute flags.
174 const std::bitset<NUM_COMMAND_ATTRIBUTES> attributes;
175 /// Corresponding response for requests; InvalidCmd if no
176 /// response is applicable.
177 const Command response;
178 /// String representation (for printing)
179 const std::string str;
180 };
181
182 /// Array to map Command enum to associated info.
183 static const CommandInfo commandInfo[];
184
185 private:
186
187 Command cmd;
188
189 bool
190 testCmdAttrib(MemCmd::Attribute attrib) const
191 {
192 return commandInfo[cmd].attributes[attrib] != 0;
193 }
194
195 public:
196
197 bool isRead() const { return testCmdAttrib(IsRead); }
198 bool isWrite() const { return testCmdAttrib(IsWrite); }
199 bool isUpgrade() const { return testCmdAttrib(IsUpgrade); }
200 bool isRequest() const { return testCmdAttrib(IsRequest); }
201 bool isResponse() const { return testCmdAttrib(IsResponse); }
202 bool needsWritable() const { return testCmdAttrib(NeedsWritable); }
203 bool needsResponse() const { return testCmdAttrib(NeedsResponse); }
204 bool isInvalidate() const { return testCmdAttrib(IsInvalidate); }
205 bool isEviction() const { return testCmdAttrib(IsEviction); }
206 bool isClean() const { return testCmdAttrib(IsClean); }
207 bool fromCache() const { return testCmdAttrib(FromCache); }
208
209 /**
210 * A writeback is an eviction that carries data.
211 */
212 bool isWriteback() const { return testCmdAttrib(IsEviction) &&
213 testCmdAttrib(HasData); }
214
215 /**
216 * Check if this particular packet type carries payload data. Note
217 * that this does not reflect if the data pointer of the packet is
218 * valid or not.
219 */
220 bool hasData() const { return testCmdAttrib(HasData); }
221 bool isLLSC() const { return testCmdAttrib(IsLlsc); }
222 bool isSWPrefetch() const { return testCmdAttrib(IsSWPrefetch); }
223 bool isHWPrefetch() const { return testCmdAttrib(IsHWPrefetch); }
224 bool isPrefetch() const { return testCmdAttrib(IsSWPrefetch) ||
225 testCmdAttrib(IsHWPrefetch); }
226 bool isError() const { return testCmdAttrib(IsError); }
227 bool isPrint() const { return testCmdAttrib(IsPrint); }
228 bool isFlush() const { return testCmdAttrib(IsFlush); }
229
230 Command
231 responseCommand() const
232 {
233 return commandInfo[cmd].response;
234 }
235
236 /// Return the string to a cmd given by idx.
237 const std::string &toString() const { return commandInfo[cmd].str; }
238 int toInt() const { return (int)cmd; }
239
240 MemCmd(Command _cmd) : cmd(_cmd) { }
241 MemCmd(int _cmd) : cmd((Command)_cmd) { }
242 MemCmd() : cmd(InvalidCmd) { }
243
244 bool operator==(MemCmd c2) const { return (cmd == c2.cmd); }
245 bool operator!=(MemCmd c2) const { return (cmd != c2.cmd); }
246};
247
248/**
249 * A Packet is used to encapsulate a transfer between two objects in
250 * the memory system (e.g., the L1 and L2 cache). (In contrast, a
251 * single Request travels all the way from the requester to the
252 * ultimate destination and back, possibly being conveyed by several
253 * different Packets along the way.)
254 */
255class Packet : public Printable
256{
257 public:
258 typedef uint32_t FlagsType;
259 typedef ::Flags<FlagsType> Flags;
260
261 private:
262
263 enum : FlagsType {
264 // Flags to transfer across when copying a packet
265 COPY_FLAGS = 0x0000003F,
266
267 // Does this packet have sharers (which means it should not be
268 // considered writable) or not. See setHasSharers below.
269 HAS_SHARERS = 0x00000001,
270
271 // Special control flags
272 /// Special timing-mode atomic snoop for multi-level coherence.
273 EXPRESS_SNOOP = 0x00000002,
274
275 /// Allow a responding cache to inform the cache hierarchy
276 /// that it had a writable copy before responding. See
277 /// setResponderHadWritable below.
278 RESPONDER_HAD_WRITABLE = 0x00000004,
279
280 // Snoop co-ordination flag to indicate that a cache is
281 // responding to a snoop. See setCacheResponding below.
282 CACHE_RESPONDING = 0x00000008,
283
284 // The writeback/writeclean should be propagated further
285 // downstream by the receiver
286 WRITE_THROUGH = 0x00000010,
287
288 // Response co-ordination flag for cache maintenance
289 // operations
290 SATISFIED = 0x00000020,
291
292 /// Are the 'addr' and 'size' fields valid?
293 VALID_ADDR = 0x00000100,
294 VALID_SIZE = 0x00000200,
295
296 /// Is the data pointer set to a value that shouldn't be freed
297 /// when the packet is destroyed?
298 STATIC_DATA = 0x00001000,
299 /// The data pointer points to a value that should be freed when
300 /// the packet is destroyed. The pointer is assumed to be pointing
301 /// to an array, and delete [] is consequently called
302 DYNAMIC_DATA = 0x00002000,
303
304 /// suppress the error if this packet encounters a functional
305 /// access failure.
306 SUPPRESS_FUNC_ERROR = 0x00008000,
307
308 // Signal block present to squash prefetch and cache evict packets
309 // through express snoop flag
310 BLOCK_CACHED = 0x00010000
311 };
312
313 Flags flags;
314
315 public:
316 typedef MemCmd::Command Command;
317
318 /// The command field of the packet.
319 MemCmd cmd;
320
321 const PacketId id;
322
323 /// A pointer to the original request.
324 RequestPtr req;
325
326 private:
327 /**
328 * A pointer to the data being transferred. It can be different
329 * sizes at each level of the hierarchy so it belongs to the
330 * packet, not request. This may or may not be populated when a
331 * responder receives the packet. If not populated memory should
332 * be allocated.
333 */
334 PacketDataPtr data;
335
336 /// The address of the request. This address could be virtual or
337 /// physical, depending on the system configuration.
338 Addr addr;
339
340 /// True if the request targets the secure memory space.
341 bool _isSecure;
342
343 /// The size of the request or transfer.
344 unsigned size;
345
346 /**
347 * Track the bytes found that satisfy a functional read.
348 */
349 std::vector<bool> bytesValid;
350
351 // Quality of Service priority value
352 uint8_t _qosValue;
353
354 public:
355
356 /**
357 * The extra delay from seeing the packet until the header is
358 * transmitted. This delay is used to communicate the crossbar
359 * forwarding latency to the neighbouring object (e.g. a cache)
360 * that actually makes the packet wait. As the delay is relative,
361 * a 32-bit unsigned should be sufficient.
362 */
363 uint32_t headerDelay;
364
365 /**
366 * Keep track of the extra delay incurred by snooping upwards
367 * before sending a request down the memory system. This is used
368 * by the coherent crossbar to account for the additional request
369 * delay.
370 */
371 uint32_t snoopDelay;
372
373 /**
374 * The extra pipelining delay from seeing the packet until the end of
375 * payload is transmitted by the component that provided it (if
376 * any). This includes the header delay. Similar to the header
377 * delay, this is used to make up for the fact that the
378 * crossbar does not make the packet wait. As the delay is
379 * relative, a 32-bit unsigned should be sufficient.
380 */
381 uint32_t payloadDelay;
382
383 /**
384 * A virtual base opaque structure used to hold state associated
385 * with the packet (e.g., an MSHR), specific to a MemObject that
386 * sees the packet. A pointer to this state is returned in the
387 * packet's response so that the MemObject in question can quickly
388 * look up the state needed to process it. A specific subclass
389 * would be derived from this to carry state specific to a
390 * particular sending device.
391 *
392 * As multiple MemObjects may add their SenderState throughout the
393 * memory system, the SenderStates create a stack, where a
394 * MemObject can add a new Senderstate, as long as the
395 * predecessing SenderState is restored when the response comes
396 * back. For this reason, the predecessor should always be
397 * populated with the current SenderState of a packet before
398 * modifying the senderState field in the request packet.
399 */
400 struct SenderState
401 {
402 SenderState* predecessor;
403 SenderState() : predecessor(NULL) {}
404 virtual ~SenderState() {}
405 };
406
407 /**
408 * Object used to maintain state of a PrintReq. The senderState
409 * field of a PrintReq should always be of this type.
410 */
411 class PrintReqState : public SenderState
412 {
413 private:
414 /**
415 * An entry in the label stack.
416 */
417 struct LabelStackEntry
418 {
419 const std::string label;
420 std::string *prefix;
421 bool labelPrinted;
422 LabelStackEntry(const std::string &_label, std::string *_prefix);
423 };
424
425 typedef std::list<LabelStackEntry> LabelStack;
426 LabelStack labelStack;
427
428 std::string *curPrefixPtr;
429
430 public:
431 std::ostream &os;
432 const int verbosity;
433
434 PrintReqState(std::ostream &os, int verbosity = 0);
435 ~PrintReqState();
436
437 /**
438 * Returns the current line prefix.
439 */
440 const std::string &curPrefix() { return *curPrefixPtr; }
441
442 /**
443 * Push a label onto the label stack, and prepend the given
444 * prefix string onto the current prefix. Labels will only be
445 * printed if an object within the label's scope is printed.
446 */
447 void pushLabel(const std::string &lbl,
448 const std::string &prefix = " ");
449
450 /**
451 * Pop a label off the label stack.
452 */
453 void popLabel();
454
455 /**
456 * Print all of the pending unprinted labels on the
457 * stack. Called by printObj(), so normally not called by
458 * users unless bypassing printObj().
459 */
460 void printLabels();
461
462 /**
463 * Print a Printable object to os, because it matched the
464 * address on a PrintReq.
465 */
466 void printObj(Printable *obj);
467 };
468
469 /**
470 * This packet's sender state. Devices should use dynamic_cast<>
471 * to cast to the state appropriate to the sender. The intent of
472 * this variable is to allow a device to attach extra information
473 * to a request. A response packet must return the sender state
474 * that was attached to the original request (even if a new packet
475 * is created).
476 */
477 SenderState *senderState;
478
479 /**
480 * Push a new sender state to the packet and make the current
481 * sender state the predecessor of the new one. This should be
482 * prefered over direct manipulation of the senderState member
483 * variable.
484 *
485 * @param sender_state SenderState to push at the top of the stack
486 */
487 void pushSenderState(SenderState *sender_state);
488
489 /**
490 * Pop the top of the state stack and return a pointer to it. This
491 * assumes the current sender state is not NULL. This should be
492 * preferred over direct manipulation of the senderState member
493 * variable.
494 *
495 * @return The current top of the stack
496 */
497 SenderState *popSenderState();
498
499 /**
500 * Go through the sender state stack and return the first instance
501 * that is of type T (as determined by a dynamic_cast). If there
502 * is no sender state of type T, NULL is returned.
503 *
504 * @return The topmost state of type T
505 */
506 template <typename T>
507 T * findNextSenderState() const
508 {
509 T *t = NULL;
510 SenderState* sender_state = senderState;
511 while (t == NULL && sender_state != NULL) {
512 t = dynamic_cast<T*>(sender_state);
513 sender_state = sender_state->predecessor;
514 }
515 return t;
516 }
517
518 /// Return the string name of the cmd field (for debugging and
519 /// tracing).
520 const std::string &cmdString() const { return cmd.toString(); }
521
522 /// Return the index of this command.
523 inline int cmdToIndex() const { return cmd.toInt(); }
524
525 bool isRead() const { return cmd.isRead(); }
526 bool isWrite() const { return cmd.isWrite(); }
527 bool isUpgrade() const { return cmd.isUpgrade(); }
528 bool isRequest() const { return cmd.isRequest(); }
529 bool isResponse() const { return cmd.isResponse(); }
530 bool needsWritable() const
531 {
532 // we should never check if a response needsWritable, the
533 // request has this flag, and for a response we should rather
534 // look at the hasSharers flag (if not set, the response is to
535 // be considered writable)
536 assert(isRequest());
537 return cmd.needsWritable();
538 }
539 bool needsResponse() const { return cmd.needsResponse(); }
540 bool isInvalidate() const { return cmd.isInvalidate(); }
541 bool isEviction() const { return cmd.isEviction(); }
542 bool isClean() const { return cmd.isClean(); }
543 bool fromCache() const { return cmd.fromCache(); }
544 bool isWriteback() const { return cmd.isWriteback(); }
545 bool hasData() const { return cmd.hasData(); }
546 bool hasRespData() const
547 {
548 MemCmd resp_cmd = cmd.responseCommand();
549 return resp_cmd.hasData();
550 }
551 bool isLLSC() const { return cmd.isLLSC(); }
552 bool isError() const { return cmd.isError(); }
553 bool isPrint() const { return cmd.isPrint(); }
554 bool isFlush() const { return cmd.isFlush(); }
555
556 //@{
557 /// Snoop flags
558 /**
559 * Set the cacheResponding flag. This is used by the caches to
560 * signal another cache that they are responding to a request. A
561 * cache will only respond to snoops if it has the line in either
562 * Modified or Owned state. Note that on snoop hits we always pass
563 * the line as Modified and never Owned. In the case of an Owned
564 * line we proceed to invalidate all other copies.
565 *
566 * On a cache fill (see Cache::handleFill), we check hasSharers
567 * first, ignoring the cacheResponding flag if hasSharers is set.
568 * A line is consequently allocated as:
569 *
570 * hasSharers cacheResponding state
571 * true false Shared
572 * true true Shared
573 * false false Exclusive
574 * false true Modified
575 */
576 void setCacheResponding()
577 {
578 assert(isRequest());
579 assert(!flags.isSet(CACHE_RESPONDING));
580 flags.set(CACHE_RESPONDING);
581 }
582 bool cacheResponding() const { return flags.isSet(CACHE_RESPONDING); }
583 /**
584 * On fills, the hasSharers flag is used by the caches in
585 * combination with the cacheResponding flag, as clarified
586 * above. If the hasSharers flag is not set, the packet is passing
587 * writable. Thus, a response from a memory passes the line as
588 * writable by default.
589 *
590 * The hasSharers flag is also used by upstream caches to inform a
591 * downstream cache that they have the block (by calling
592 * setHasSharers on snoop request packets that hit in upstream
593 * cachs tags or MSHRs). If the snoop packet has sharers, a
594 * downstream cache is prevented from passing a dirty line upwards
595 * if it was not explicitly asked for a writable copy. See
596 * Cache::satisfyCpuSideRequest.
597 *
598 * The hasSharers flag is also used on writebacks, in
599 * combination with the WritbackClean or WritebackDirty commands,
600 * to allocate the block downstream either as:
601 *
602 * command hasSharers state
603 * WritebackDirty false Modified
604 * WritebackDirty true Owned
605 * WritebackClean false Exclusive
606 * WritebackClean true Shared
607 */
608 void setHasSharers() { flags.set(HAS_SHARERS); }
609 bool hasSharers() const { return flags.isSet(HAS_SHARERS); }
610 //@}
611
612 /**
613 * The express snoop flag is used for two purposes. Firstly, it is
614 * used to bypass flow control for normal (non-snoop) requests
615 * going downstream in the memory system. In cases where a cache
616 * is responding to a snoop from another cache (it had a dirty
617 * line), but the line is not writable (and there are possibly
618 * other copies), the express snoop flag is set by the downstream
619 * cache to invalidate all other copies in zero time. Secondly,
620 * the express snoop flag is also set to be able to distinguish
621 * snoop packets that came from a downstream cache, rather than
622 * snoop packets from neighbouring caches.
623 */
624 void setExpressSnoop() { flags.set(EXPRESS_SNOOP); }
625 bool isExpressSnoop() const { return flags.isSet(EXPRESS_SNOOP); }
626
627 /**
628 * On responding to a snoop request (which only happens for
629 * Modified or Owned lines), make sure that we can transform an
630 * Owned response to a Modified one. If this flag is not set, the
631 * responding cache had the line in the Owned state, and there are
632 * possibly other Shared copies in the memory system. A downstream
633 * cache helps in orchestrating the invalidation of these copies
634 * by sending out the appropriate express snoops.
635 */
636 void setResponderHadWritable()
637 {
638 assert(cacheResponding());
639 assert(!responderHadWritable());
640 flags.set(RESPONDER_HAD_WRITABLE);
641 }
642 bool responderHadWritable() const
643 { return flags.isSet(RESPONDER_HAD_WRITABLE); }
644
645 /**
646 * A writeback/writeclean cmd gets propagated further downstream
647 * by the receiver when the flag is set.
648 */
649 void setWriteThrough()
650 {
651 assert(cmd.isWrite() &&
652 (cmd.isEviction() || cmd == MemCmd::WriteClean));
653 flags.set(WRITE_THROUGH);
654 }
655 void clearWriteThrough() { flags.clear(WRITE_THROUGH); }
656 bool writeThrough() const { return flags.isSet(WRITE_THROUGH); }
657
658 /**
659 * Set when a request hits in a cache and the cache is not going
660 * to respond. This is used by the crossbar to coordinate
661 * responses for cache maintenance operations.
662 */
663 void setSatisfied()
664 {
665 assert(cmd.isClean());
666 assert(!flags.isSet(SATISFIED));
667 flags.set(SATISFIED);
668 }
669 bool satisfied() const { return flags.isSet(SATISFIED); }
670
671 void setSuppressFuncError() { flags.set(SUPPRESS_FUNC_ERROR); }
672 bool suppressFuncError() const { return flags.isSet(SUPPRESS_FUNC_ERROR); }
673 void setBlockCached() { flags.set(BLOCK_CACHED); }
674 bool isBlockCached() const { return flags.isSet(BLOCK_CACHED); }
675 void clearBlockCached() { flags.clear(BLOCK_CACHED); }
676
677 /**
678 * QoS Value getter
679 * Returns 0 if QoS value was never set (constructor default).
680 *
681 * @return QoS priority value of the packet
682 */
683 inline uint8_t qosValue() const { return _qosValue; }
684
685 /**
686 * QoS Value setter
687 * Interface for setting QoS priority value of the packet.
688 *
689 * @param qos_value QoS priority value
690 */
691 inline void qosValue(const uint8_t qos_value)
692 { _qosValue = qos_value; }
693
694 inline MasterID masterId() const { return req->masterId(); }
695
696 // Network error conditions... encapsulate them as methods since
697 // their encoding keeps changing (from result field to command
698 // field, etc.)
699 void
700 setBadAddress()
701 {
702 assert(isResponse());
703 cmd = MemCmd::BadAddressError;
704 }
705
706 void copyError(Packet *pkt) { assert(pkt->isError()); cmd = pkt->cmd; }
707
708 Addr getAddr() const { assert(flags.isSet(VALID_ADDR)); return addr; }
709 /**
710 * Update the address of this packet mid-transaction. This is used
711 * by the address mapper to change an already set address to a new
712 * one based on the system configuration. It is intended to remap
713 * an existing address, so it asserts that the current address is
714 * valid.
715 */
716 void setAddr(Addr _addr) { assert(flags.isSet(VALID_ADDR)); addr = _addr; }
717
718 unsigned getSize() const { assert(flags.isSet(VALID_SIZE)); return size; }
719
720 Addr getOffset(unsigned int blk_size) const
721 {
722 return getAddr() & Addr(blk_size - 1);
723 }
724
725 Addr getBlockAddr(unsigned int blk_size) const
726 {
727 return getAddr() & ~(Addr(blk_size - 1));
728 }
729
730 bool isSecure() const
731 {
732 assert(flags.isSet(VALID_ADDR));
733 return _isSecure;
734 }
735
736 /**
737 * Accessor function to atomic op.
738 */
739 AtomicOpFunctor *getAtomicOp() const { return req->getAtomicOpFunctor(); }
740 bool isAtomicOp() const { return req->isAtomic(); }
741
742 /**
743 * It has been determined that the SC packet should successfully update
744 * memory. Therefore, convert this SC packet to a normal write.
745 */
746 void
747 convertScToWrite()
748 {
749 assert(isLLSC());
750 assert(isWrite());
751 cmd = MemCmd::WriteReq;
752 }
753
754 /**
755 * When ruby is in use, Ruby will monitor the cache line and the
756 * phys memory should treat LL ops as normal reads.
757 */
758 void
759 convertLlToRead()
760 {
761 assert(isLLSC());
762 assert(isRead());
763 cmd = MemCmd::ReadReq;
764 }
765
766 /**
767 * Constructor. Note that a Request object must be constructed
768 * first, but the Requests's physical address and size fields need
769 * not be valid. The command must be supplied.
770 */
771 Packet(const RequestPtr &_req, MemCmd _cmd)
772 : cmd(_cmd), id((PacketId)_req.get()), req(_req),
773 data(nullptr), addr(0), _isSecure(false), size(0),
774 _qosValue(0), headerDelay(0), snoopDelay(0),
775 payloadDelay(0), senderState(NULL)
776 {
777 if (req->hasPaddr()) {
778 addr = req->getPaddr();
779 flags.set(VALID_ADDR);
780 _isSecure = req->isSecure();
781 }
782 if (req->hasSize()) {
783 size = req->getSize();
784 flags.set(VALID_SIZE);
785 }
786 }
787
788 /**
789 * Alternate constructor if you are trying to create a packet with
790 * a request that is for a whole block, not the address from the
791 * req. this allows for overriding the size/addr of the req.
792 */
793 Packet(const RequestPtr &_req, MemCmd _cmd, int _blkSize, PacketId _id = 0)
794 : cmd(_cmd), id(_id ? _id : (PacketId)_req.get()), req(_req),
795 data(nullptr), addr(0), _isSecure(false),
796 _qosValue(0), headerDelay(0),
797 snoopDelay(0), payloadDelay(0), senderState(NULL)
798 {
799 if (req->hasPaddr()) {
800 addr = req->getPaddr() & ~(_blkSize - 1);
801 flags.set(VALID_ADDR);
802 _isSecure = req->isSecure();
803 }
804 size = _blkSize;
805 flags.set(VALID_SIZE);
806 }
807
808 /**
809 * Alternate constructor for copying a packet. Copy all fields
810 * *except* if the original packet's data was dynamic, don't copy
811 * that, as we can't guarantee that the new packet's lifetime is
812 * less than that of the original packet. In this case the new
813 * packet should allocate its own data.
814 */
815 Packet(const PacketPtr pkt, bool clear_flags, bool alloc_data)
816 : cmd(pkt->cmd), id(pkt->id), req(pkt->req),
817 data(nullptr),
818 addr(pkt->addr), _isSecure(pkt->_isSecure), size(pkt->size),
819 bytesValid(pkt->bytesValid),
820 _qosValue(pkt->qosValue()),
821 headerDelay(pkt->headerDelay),
822 snoopDelay(0),
823 payloadDelay(pkt->payloadDelay),
824 senderState(pkt->senderState)
825 {
826 if (!clear_flags)
827 flags.set(pkt->flags & COPY_FLAGS);
828
829 flags.set(pkt->flags & (VALID_ADDR|VALID_SIZE));
830
831 // should we allocate space for data, or not, the express
832 // snoops do not need to carry any data as they only serve to
833 // co-ordinate state changes
834 if (alloc_data) {
835 // even if asked to allocate data, if the original packet
836 // holds static data, then the sender will not be doing
837 // any memcpy on receiving the response, thus we simply
838 // carry the pointer forward
839 if (pkt->flags.isSet(STATIC_DATA)) {
840 data = pkt->data;
841 flags.set(STATIC_DATA);
842 } else {
843 allocate();
844 }
845 }
846 }
847
848 /**
849 * Generate the appropriate read MemCmd based on the Request flags.
850 */
851 static MemCmd
852 makeReadCmd(const RequestPtr &req)
853 {
854 if (req->isLLSC())
855 return MemCmd::LoadLockedReq;
856 else if (req->isPrefetch())
857 return MemCmd::SoftPFReq;
858 else
859 return MemCmd::ReadReq;
860 }
861
862 /**
863 * Generate the appropriate write MemCmd based on the Request flags.
864 */
865 static MemCmd
866 makeWriteCmd(const RequestPtr &req)
867 {
868 if (req->isLLSC())
869 return MemCmd::StoreCondReq;
870 else if (req->isSwap() || req->isAtomic())
871 return MemCmd::SwapReq;
872 else if (req->isCacheInvalidate()) {
873 return req->isCacheClean() ? MemCmd::CleanInvalidReq :
874 MemCmd::InvalidateReq;
875 } else if (req->isCacheClean()) {
876 return MemCmd::CleanSharedReq;
877 } else
878 return MemCmd::WriteReq;
879 }
880
881 /**
882 * Constructor-like methods that return Packets based on Request objects.
883 * Fine-tune the MemCmd type if it's not a vanilla read or write.
884 */
885 static PacketPtr
886 createRead(const RequestPtr &req)
887 {
888 return new Packet(req, makeReadCmd(req));
889 }
890
891 static PacketPtr
892 createWrite(const RequestPtr &req)
893 {
894 return new Packet(req, makeWriteCmd(req));
895 }
896
897 /**
898 * clean up packet variables
899 */
900 ~Packet()
901 {
902 deleteData();
903 }
904
905 /**
906 * Take a request packet and modify it in place to be suitable for
907 * returning as a response to that request.
908 */
909 void
910 makeResponse()
911 {
912 assert(needsResponse());
913 assert(isRequest());
914 cmd = cmd.responseCommand();
915
916 // responses are never express, even if the snoop that
917 // triggered them was
918 flags.clear(EXPRESS_SNOOP);
919 }
920
921 void
922 makeAtomicResponse()
923 {
924 makeResponse();
925 }
926
927 void
928 makeTimingResponse()
929 {
930 makeResponse();
931 }
932
933 void
934 setFunctionalResponseStatus(bool success)
935 {
936 if (!success) {
937 if (isWrite()) {
938 cmd = MemCmd::FunctionalWriteError;
939 } else {
940 cmd = MemCmd::FunctionalReadError;
941 }
942 }
943 }
944
945 void
946 setSize(unsigned size)
947 {
948 assert(!flags.isSet(VALID_SIZE));
949
950 this->size = size;
951 flags.set(VALID_SIZE);
952 }
953
954
955 public:
956 /**
957 * @{
958 * @name Data accessor mehtods
959 */
960
961 /**
962 * Set the data pointer to the following value that should not be
963 * freed. Static data allows us to do a single memcpy even if
964 * multiple packets are required to get from source to destination
965 * and back. In essence the pointer is set calling dataStatic on
966 * the original packet, and whenever this packet is copied and
967 * forwarded the same pointer is passed on. When a packet
968 * eventually reaches the destination holding the data, it is
969 * copied once into the location originally set. On the way back
970 * to the source, no copies are necessary.
971 */
972 template <typename T>
973 void
974 dataStatic(T *p)
975 {
976 assert(flags.noneSet(STATIC_DATA|DYNAMIC_DATA));
977 data = (PacketDataPtr)p;
978 flags.set(STATIC_DATA);
979 }
980
981 /**
982 * Set the data pointer to the following value that should not be
983 * freed. This version of the function allows the pointer passed
984 * to us to be const. To avoid issues down the line we cast the
985 * constness away, the alternative would be to keep both a const
986 * and non-const data pointer and cleverly choose between
987 * them. Note that this is only allowed for static data.
988 */
989 template <typename T>
990 void
991 dataStaticConst(const T *p)
992 {
993 assert(flags.noneSet(STATIC_DATA|DYNAMIC_DATA));
994 data = const_cast<PacketDataPtr>(p);
995 flags.set(STATIC_DATA);
996 }
997
998 /**
999 * Set the data pointer to a value that should have delete []
1000 * called on it. Dynamic data is local to this packet, and as the
1001 * packet travels from source to destination, forwarded packets
1002 * will allocate their own data. When a packet reaches the final
1003 * destination it will populate the dynamic data of that specific
1004 * packet, and on the way back towards the source, memcpy will be
1005 * invoked in every step where a new packet was created e.g. in
1006 * the caches. Ultimately when the response reaches the source a
1007 * final memcpy is needed to extract the data from the packet
1008 * before it is deallocated.
1009 */
1010 template <typename T>
1011 void
1012 dataDynamic(T *p)
1013 {
1014 assert(flags.noneSet(STATIC_DATA|DYNAMIC_DATA));
1015 data = (PacketDataPtr)p;
1016 flags.set(DYNAMIC_DATA);
1017 }
1018
1019 /**
1020 * get a pointer to the data ptr.
1021 */
1022 template <typename T>
1023 T*
1024 getPtr()
1025 {
1026 assert(flags.isSet(STATIC_DATA|DYNAMIC_DATA));
1027 return (T*)data;
1028 }
1029
1030 template <typename T>
1031 const T*
1032 getConstPtr() const
1033 {
1034 assert(flags.isSet(STATIC_DATA|DYNAMIC_DATA));
1035 return (const T*)data;
1036 }
1037
1038 /**
1039 * Get the data in the packet byte swapped from big endian to
1040 * host endian.
1041 */
1042 template <typename T>
1043 T getBE() const;
1044
1045 /**
1046 * Get the data in the packet byte swapped from little endian to
1047 * host endian.
1048 */
1049 template <typename T>
1050 T getLE() const;
1051
1052 /**
1053 * Get the data in the packet byte swapped from the specified
1054 * endianness.
1055 */
1056 template <typename T>
1057 T get(ByteOrder endian) const;
1058
1059#if THE_ISA != NULL_ISA
1060 /**
1061 * Get the data in the packet byte swapped from guest to host
1062 * endian.
1063 */
1064 template <typename T>
| 1/*
2 * Copyright (c) 2012-2018 ARM Limited
3 * All rights reserved
4 *
5 * The license below extends only to copyright in the software and shall
6 * not be construed as granting a license to any other intellectual
7 * property including but not limited to intellectual property relating
8 * to a hardware implementation of the functionality of the software
9 * licensed hereunder. You may use the software subject to the license
10 * terms below provided that you ensure that this notice is replicated
11 * unmodified and in its entirety in all distributions of the software,
12 * modified or unmodified, in source code or in binary form.
13 *
14 * Copyright (c) 2006 The Regents of The University of Michigan
15 * Copyright (c) 2010,2015 Advanced Micro Devices, Inc.
16 * All rights reserved.
17 *
18 * Redistribution and use in source and binary forms, with or without
19 * modification, are permitted provided that the following conditions are
20 * met: redistributions of source code must retain the above copyright
21 * notice, this list of conditions and the following disclaimer;
22 * redistributions in binary form must reproduce the above copyright
23 * notice, this list of conditions and the following disclaimer in the
24 * documentation and/or other materials provided with the distribution;
25 * neither the name of the copyright holders nor the names of its
26 * contributors may be used to endorse or promote products derived from
27 * this software without specific prior written permission.
28 *
29 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
30 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
31 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
32 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
33 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
34 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
35 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
36 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
37 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
38 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
39 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
40 *
41 * Authors: Ron Dreslinski
42 * Steve Reinhardt
43 * Ali Saidi
44 * Andreas Hansson
45 * Nikos Nikoleris
46 */
47
48/**
49 * @file
50 * Declaration of the Packet class.
51 */
52
53#ifndef __MEM_PACKET_HH__
54#define __MEM_PACKET_HH__
55
56#include <bitset>
57#include <cassert>
58#include <list>
59
60#include "base/cast.hh"
61#include "base/compiler.hh"
62#include "base/flags.hh"
63#include "base/logging.hh"
64#include "base/printable.hh"
65#include "base/types.hh"
66#include "config/the_isa.hh"
67#include "mem/request.hh"
68#include "sim/core.hh"
69
70class Packet;
71typedef Packet *PacketPtr;
72typedef uint8_t* PacketDataPtr;
73typedef std::list<PacketPtr> PacketList;
74typedef uint64_t PacketId;
75
76class MemCmd
77{
78 friend class Packet;
79
80 public:
81 /**
82 * List of all commands associated with a packet.
83 */
84 enum Command
85 {
86 InvalidCmd,
87 ReadReq,
88 ReadResp,
89 ReadRespWithInvalidate,
90 WriteReq,
91 WriteResp,
92 WritebackDirty,
93 WritebackClean,
94 WriteClean, // writes dirty data below without evicting
95 CleanEvict,
96 SoftPFReq,
97 HardPFReq,
98 SoftPFResp,
99 HardPFResp,
100 WriteLineReq,
101 UpgradeReq,
102 SCUpgradeReq, // Special "weak" upgrade for StoreCond
103 UpgradeResp,
104 SCUpgradeFailReq, // Failed SCUpgradeReq in MSHR (never sent)
105 UpgradeFailResp, // Valid for SCUpgradeReq only
106 ReadExReq,
107 ReadExResp,
108 ReadCleanReq,
109 ReadSharedReq,
110 LoadLockedReq,
111 StoreCondReq,
112 StoreCondFailReq, // Failed StoreCondReq in MSHR (never sent)
113 StoreCondResp,
114 SwapReq,
115 SwapResp,
116 MessageReq,
117 MessageResp,
118 MemFenceReq,
119 MemFenceResp,
120 CleanSharedReq,
121 CleanSharedResp,
122 CleanInvalidReq,
123 CleanInvalidResp,
124 // Error responses
125 // @TODO these should be classified as responses rather than
126 // requests; coding them as requests initially for backwards
127 // compatibility
128 InvalidDestError, // packet dest field invalid
129 BadAddressError, // memory address invalid
130 FunctionalReadError, // unable to fulfill functional read
131 FunctionalWriteError, // unable to fulfill functional write
132 // Fake simulator-only commands
133 PrintReq, // Print state matching address
134 FlushReq, //request for a cache flush
135 InvalidateReq, // request for address to be invalidated
136 InvalidateResp,
137 NUM_MEM_CMDS
138 };
139
140 private:
141 /**
142 * List of command attributes.
143 */
144 enum Attribute
145 {
146 IsRead, //!< Data flows from responder to requester
147 IsWrite, //!< Data flows from requester to responder
148 IsUpgrade,
149 IsInvalidate,
150 IsClean, //!< Cleans any existing dirty blocks
151 NeedsWritable, //!< Requires writable copy to complete in-cache
152 IsRequest, //!< Issued by requester
153 IsResponse, //!< Issue by responder
154 NeedsResponse, //!< Requester needs response from target
155 IsEviction,
156 IsSWPrefetch,
157 IsHWPrefetch,
158 IsLlsc, //!< Alpha/MIPS LL or SC access
159 HasData, //!< There is an associated payload
160 IsError, //!< Error response
161 IsPrint, //!< Print state matching address (for debugging)
162 IsFlush, //!< Flush the address from caches
163 FromCache, //!< Request originated from a caching agent
164 NUM_COMMAND_ATTRIBUTES
165 };
166
167 /**
168 * Structure that defines attributes and other data associated
169 * with a Command.
170 */
171 struct CommandInfo
172 {
173 /// Set of attribute flags.
174 const std::bitset<NUM_COMMAND_ATTRIBUTES> attributes;
175 /// Corresponding response for requests; InvalidCmd if no
176 /// response is applicable.
177 const Command response;
178 /// String representation (for printing)
179 const std::string str;
180 };
181
182 /// Array to map Command enum to associated info.
183 static const CommandInfo commandInfo[];
184
185 private:
186
187 Command cmd;
188
189 bool
190 testCmdAttrib(MemCmd::Attribute attrib) const
191 {
192 return commandInfo[cmd].attributes[attrib] != 0;
193 }
194
195 public:
196
197 bool isRead() const { return testCmdAttrib(IsRead); }
198 bool isWrite() const { return testCmdAttrib(IsWrite); }
199 bool isUpgrade() const { return testCmdAttrib(IsUpgrade); }
200 bool isRequest() const { return testCmdAttrib(IsRequest); }
201 bool isResponse() const { return testCmdAttrib(IsResponse); }
202 bool needsWritable() const { return testCmdAttrib(NeedsWritable); }
203 bool needsResponse() const { return testCmdAttrib(NeedsResponse); }
204 bool isInvalidate() const { return testCmdAttrib(IsInvalidate); }
205 bool isEviction() const { return testCmdAttrib(IsEviction); }
206 bool isClean() const { return testCmdAttrib(IsClean); }
207 bool fromCache() const { return testCmdAttrib(FromCache); }
208
209 /**
210 * A writeback is an eviction that carries data.
211 */
212 bool isWriteback() const { return testCmdAttrib(IsEviction) &&
213 testCmdAttrib(HasData); }
214
215 /**
216 * Check if this particular packet type carries payload data. Note
217 * that this does not reflect if the data pointer of the packet is
218 * valid or not.
219 */
220 bool hasData() const { return testCmdAttrib(HasData); }
221 bool isLLSC() const { return testCmdAttrib(IsLlsc); }
222 bool isSWPrefetch() const { return testCmdAttrib(IsSWPrefetch); }
223 bool isHWPrefetch() const { return testCmdAttrib(IsHWPrefetch); }
224 bool isPrefetch() const { return testCmdAttrib(IsSWPrefetch) ||
225 testCmdAttrib(IsHWPrefetch); }
226 bool isError() const { return testCmdAttrib(IsError); }
227 bool isPrint() const { return testCmdAttrib(IsPrint); }
228 bool isFlush() const { return testCmdAttrib(IsFlush); }
229
230 Command
231 responseCommand() const
232 {
233 return commandInfo[cmd].response;
234 }
235
236 /// Return the string to a cmd given by idx.
237 const std::string &toString() const { return commandInfo[cmd].str; }
238 int toInt() const { return (int)cmd; }
239
240 MemCmd(Command _cmd) : cmd(_cmd) { }
241 MemCmd(int _cmd) : cmd((Command)_cmd) { }
242 MemCmd() : cmd(InvalidCmd) { }
243
244 bool operator==(MemCmd c2) const { return (cmd == c2.cmd); }
245 bool operator!=(MemCmd c2) const { return (cmd != c2.cmd); }
246};
247
248/**
249 * A Packet is used to encapsulate a transfer between two objects in
250 * the memory system (e.g., the L1 and L2 cache). (In contrast, a
251 * single Request travels all the way from the requester to the
252 * ultimate destination and back, possibly being conveyed by several
253 * different Packets along the way.)
254 */
255class Packet : public Printable
256{
257 public:
258 typedef uint32_t FlagsType;
259 typedef ::Flags<FlagsType> Flags;
260
261 private:
262
263 enum : FlagsType {
264 // Flags to transfer across when copying a packet
265 COPY_FLAGS = 0x0000003F,
266
267 // Does this packet have sharers (which means it should not be
268 // considered writable) or not. See setHasSharers below.
269 HAS_SHARERS = 0x00000001,
270
271 // Special control flags
272 /// Special timing-mode atomic snoop for multi-level coherence.
273 EXPRESS_SNOOP = 0x00000002,
274
275 /// Allow a responding cache to inform the cache hierarchy
276 /// that it had a writable copy before responding. See
277 /// setResponderHadWritable below.
278 RESPONDER_HAD_WRITABLE = 0x00000004,
279
280 // Snoop co-ordination flag to indicate that a cache is
281 // responding to a snoop. See setCacheResponding below.
282 CACHE_RESPONDING = 0x00000008,
283
284 // The writeback/writeclean should be propagated further
285 // downstream by the receiver
286 WRITE_THROUGH = 0x00000010,
287
288 // Response co-ordination flag for cache maintenance
289 // operations
290 SATISFIED = 0x00000020,
291
292 /// Are the 'addr' and 'size' fields valid?
293 VALID_ADDR = 0x00000100,
294 VALID_SIZE = 0x00000200,
295
296 /// Is the data pointer set to a value that shouldn't be freed
297 /// when the packet is destroyed?
298 STATIC_DATA = 0x00001000,
299 /// The data pointer points to a value that should be freed when
300 /// the packet is destroyed. The pointer is assumed to be pointing
301 /// to an array, and delete [] is consequently called
302 DYNAMIC_DATA = 0x00002000,
303
304 /// suppress the error if this packet encounters a functional
305 /// access failure.
306 SUPPRESS_FUNC_ERROR = 0x00008000,
307
308 // Signal block present to squash prefetch and cache evict packets
309 // through express snoop flag
310 BLOCK_CACHED = 0x00010000
311 };
312
313 Flags flags;
314
315 public:
316 typedef MemCmd::Command Command;
317
318 /// The command field of the packet.
319 MemCmd cmd;
320
321 const PacketId id;
322
323 /// A pointer to the original request.
324 RequestPtr req;
325
326 private:
327 /**
328 * A pointer to the data being transferred. It can be different
329 * sizes at each level of the hierarchy so it belongs to the
330 * packet, not request. This may or may not be populated when a
331 * responder receives the packet. If not populated memory should
332 * be allocated.
333 */
334 PacketDataPtr data;
335
336 /// The address of the request. This address could be virtual or
337 /// physical, depending on the system configuration.
338 Addr addr;
339
340 /// True if the request targets the secure memory space.
341 bool _isSecure;
342
343 /// The size of the request or transfer.
344 unsigned size;
345
346 /**
347 * Track the bytes found that satisfy a functional read.
348 */
349 std::vector<bool> bytesValid;
350
351 // Quality of Service priority value
352 uint8_t _qosValue;
353
354 public:
355
356 /**
357 * The extra delay from seeing the packet until the header is
358 * transmitted. This delay is used to communicate the crossbar
359 * forwarding latency to the neighbouring object (e.g. a cache)
360 * that actually makes the packet wait. As the delay is relative,
361 * a 32-bit unsigned should be sufficient.
362 */
363 uint32_t headerDelay;
364
365 /**
366 * Keep track of the extra delay incurred by snooping upwards
367 * before sending a request down the memory system. This is used
368 * by the coherent crossbar to account for the additional request
369 * delay.
370 */
371 uint32_t snoopDelay;
372
373 /**
374 * The extra pipelining delay from seeing the packet until the end of
375 * payload is transmitted by the component that provided it (if
376 * any). This includes the header delay. Similar to the header
377 * delay, this is used to make up for the fact that the
378 * crossbar does not make the packet wait. As the delay is
379 * relative, a 32-bit unsigned should be sufficient.
380 */
381 uint32_t payloadDelay;
382
383 /**
384 * A virtual base opaque structure used to hold state associated
385 * with the packet (e.g., an MSHR), specific to a MemObject that
386 * sees the packet. A pointer to this state is returned in the
387 * packet's response so that the MemObject in question can quickly
388 * look up the state needed to process it. A specific subclass
389 * would be derived from this to carry state specific to a
390 * particular sending device.
391 *
392 * As multiple MemObjects may add their SenderState throughout the
393 * memory system, the SenderStates create a stack, where a
394 * MemObject can add a new Senderstate, as long as the
395 * predecessing SenderState is restored when the response comes
396 * back. For this reason, the predecessor should always be
397 * populated with the current SenderState of a packet before
398 * modifying the senderState field in the request packet.
399 */
400 struct SenderState
401 {
402 SenderState* predecessor;
403 SenderState() : predecessor(NULL) {}
404 virtual ~SenderState() {}
405 };
406
407 /**
408 * Object used to maintain state of a PrintReq. The senderState
409 * field of a PrintReq should always be of this type.
410 */
411 class PrintReqState : public SenderState
412 {
413 private:
414 /**
415 * An entry in the label stack.
416 */
417 struct LabelStackEntry
418 {
419 const std::string label;
420 std::string *prefix;
421 bool labelPrinted;
422 LabelStackEntry(const std::string &_label, std::string *_prefix);
423 };
424
425 typedef std::list<LabelStackEntry> LabelStack;
426 LabelStack labelStack;
427
428 std::string *curPrefixPtr;
429
430 public:
431 std::ostream &os;
432 const int verbosity;
433
434 PrintReqState(std::ostream &os, int verbosity = 0);
435 ~PrintReqState();
436
437 /**
438 * Returns the current line prefix.
439 */
440 const std::string &curPrefix() { return *curPrefixPtr; }
441
442 /**
443 * Push a label onto the label stack, and prepend the given
444 * prefix string onto the current prefix. Labels will only be
445 * printed if an object within the label's scope is printed.
446 */
447 void pushLabel(const std::string &lbl,
448 const std::string &prefix = " ");
449
450 /**
451 * Pop a label off the label stack.
452 */
453 void popLabel();
454
455 /**
456 * Print all of the pending unprinted labels on the
457 * stack. Called by printObj(), so normally not called by
458 * users unless bypassing printObj().
459 */
460 void printLabels();
461
462 /**
463 * Print a Printable object to os, because it matched the
464 * address on a PrintReq.
465 */
466 void printObj(Printable *obj);
467 };
468
469 /**
470 * This packet's sender state. Devices should use dynamic_cast<>
471 * to cast to the state appropriate to the sender. The intent of
472 * this variable is to allow a device to attach extra information
473 * to a request. A response packet must return the sender state
474 * that was attached to the original request (even if a new packet
475 * is created).
476 */
477 SenderState *senderState;
478
479 /**
480 * Push a new sender state to the packet and make the current
481 * sender state the predecessor of the new one. This should be
482 * prefered over direct manipulation of the senderState member
483 * variable.
484 *
485 * @param sender_state SenderState to push at the top of the stack
486 */
487 void pushSenderState(SenderState *sender_state);
488
489 /**
490 * Pop the top of the state stack and return a pointer to it. This
491 * assumes the current sender state is not NULL. This should be
492 * preferred over direct manipulation of the senderState member
493 * variable.
494 *
495 * @return The current top of the stack
496 */
497 SenderState *popSenderState();
498
499 /**
500 * Go through the sender state stack and return the first instance
501 * that is of type T (as determined by a dynamic_cast). If there
502 * is no sender state of type T, NULL is returned.
503 *
504 * @return The topmost state of type T
505 */
506 template <typename T>
507 T * findNextSenderState() const
508 {
509 T *t = NULL;
510 SenderState* sender_state = senderState;
511 while (t == NULL && sender_state != NULL) {
512 t = dynamic_cast<T*>(sender_state);
513 sender_state = sender_state->predecessor;
514 }
515 return t;
516 }
517
518 /// Return the string name of the cmd field (for debugging and
519 /// tracing).
520 const std::string &cmdString() const { return cmd.toString(); }
521
522 /// Return the index of this command.
523 inline int cmdToIndex() const { return cmd.toInt(); }
524
525 bool isRead() const { return cmd.isRead(); }
526 bool isWrite() const { return cmd.isWrite(); }
527 bool isUpgrade() const { return cmd.isUpgrade(); }
528 bool isRequest() const { return cmd.isRequest(); }
529 bool isResponse() const { return cmd.isResponse(); }
530 bool needsWritable() const
531 {
532 // we should never check if a response needsWritable, the
533 // request has this flag, and for a response we should rather
534 // look at the hasSharers flag (if not set, the response is to
535 // be considered writable)
536 assert(isRequest());
537 return cmd.needsWritable();
538 }
539 bool needsResponse() const { return cmd.needsResponse(); }
540 bool isInvalidate() const { return cmd.isInvalidate(); }
541 bool isEviction() const { return cmd.isEviction(); }
542 bool isClean() const { return cmd.isClean(); }
543 bool fromCache() const { return cmd.fromCache(); }
544 bool isWriteback() const { return cmd.isWriteback(); }
545 bool hasData() const { return cmd.hasData(); }
546 bool hasRespData() const
547 {
548 MemCmd resp_cmd = cmd.responseCommand();
549 return resp_cmd.hasData();
550 }
551 bool isLLSC() const { return cmd.isLLSC(); }
552 bool isError() const { return cmd.isError(); }
553 bool isPrint() const { return cmd.isPrint(); }
554 bool isFlush() const { return cmd.isFlush(); }
555
556 //@{
557 /// Snoop flags
558 /**
559 * Set the cacheResponding flag. This is used by the caches to
560 * signal another cache that they are responding to a request. A
561 * cache will only respond to snoops if it has the line in either
562 * Modified or Owned state. Note that on snoop hits we always pass
563 * the line as Modified and never Owned. In the case of an Owned
564 * line we proceed to invalidate all other copies.
565 *
566 * On a cache fill (see Cache::handleFill), we check hasSharers
567 * first, ignoring the cacheResponding flag if hasSharers is set.
568 * A line is consequently allocated as:
569 *
570 * hasSharers cacheResponding state
571 * true false Shared
572 * true true Shared
573 * false false Exclusive
574 * false true Modified
575 */
576 void setCacheResponding()
577 {
578 assert(isRequest());
579 assert(!flags.isSet(CACHE_RESPONDING));
580 flags.set(CACHE_RESPONDING);
581 }
582 bool cacheResponding() const { return flags.isSet(CACHE_RESPONDING); }
583 /**
584 * On fills, the hasSharers flag is used by the caches in
585 * combination with the cacheResponding flag, as clarified
586 * above. If the hasSharers flag is not set, the packet is passing
587 * writable. Thus, a response from a memory passes the line as
588 * writable by default.
589 *
590 * The hasSharers flag is also used by upstream caches to inform a
591 * downstream cache that they have the block (by calling
592 * setHasSharers on snoop request packets that hit in upstream
593 * cachs tags or MSHRs). If the snoop packet has sharers, a
594 * downstream cache is prevented from passing a dirty line upwards
595 * if it was not explicitly asked for a writable copy. See
596 * Cache::satisfyCpuSideRequest.
597 *
598 * The hasSharers flag is also used on writebacks, in
599 * combination with the WritbackClean or WritebackDirty commands,
600 * to allocate the block downstream either as:
601 *
602 * command hasSharers state
603 * WritebackDirty false Modified
604 * WritebackDirty true Owned
605 * WritebackClean false Exclusive
606 * WritebackClean true Shared
607 */
608 void setHasSharers() { flags.set(HAS_SHARERS); }
609 bool hasSharers() const { return flags.isSet(HAS_SHARERS); }
610 //@}
611
612 /**
613 * The express snoop flag is used for two purposes. Firstly, it is
614 * used to bypass flow control for normal (non-snoop) requests
615 * going downstream in the memory system. In cases where a cache
616 * is responding to a snoop from another cache (it had a dirty
617 * line), but the line is not writable (and there are possibly
618 * other copies), the express snoop flag is set by the downstream
619 * cache to invalidate all other copies in zero time. Secondly,
620 * the express snoop flag is also set to be able to distinguish
621 * snoop packets that came from a downstream cache, rather than
622 * snoop packets from neighbouring caches.
623 */
624 void setExpressSnoop() { flags.set(EXPRESS_SNOOP); }
625 bool isExpressSnoop() const { return flags.isSet(EXPRESS_SNOOP); }
626
627 /**
628 * On responding to a snoop request (which only happens for
629 * Modified or Owned lines), make sure that we can transform an
630 * Owned response to a Modified one. If this flag is not set, the
631 * responding cache had the line in the Owned state, and there are
632 * possibly other Shared copies in the memory system. A downstream
633 * cache helps in orchestrating the invalidation of these copies
634 * by sending out the appropriate express snoops.
635 */
636 void setResponderHadWritable()
637 {
638 assert(cacheResponding());
639 assert(!responderHadWritable());
640 flags.set(RESPONDER_HAD_WRITABLE);
641 }
642 bool responderHadWritable() const
643 { return flags.isSet(RESPONDER_HAD_WRITABLE); }
644
645 /**
646 * A writeback/writeclean cmd gets propagated further downstream
647 * by the receiver when the flag is set.
648 */
649 void setWriteThrough()
650 {
651 assert(cmd.isWrite() &&
652 (cmd.isEviction() || cmd == MemCmd::WriteClean));
653 flags.set(WRITE_THROUGH);
654 }
655 void clearWriteThrough() { flags.clear(WRITE_THROUGH); }
656 bool writeThrough() const { return flags.isSet(WRITE_THROUGH); }
657
658 /**
659 * Set when a request hits in a cache and the cache is not going
660 * to respond. This is used by the crossbar to coordinate
661 * responses for cache maintenance operations.
662 */
663 void setSatisfied()
664 {
665 assert(cmd.isClean());
666 assert(!flags.isSet(SATISFIED));
667 flags.set(SATISFIED);
668 }
669 bool satisfied() const { return flags.isSet(SATISFIED); }
670
671 void setSuppressFuncError() { flags.set(SUPPRESS_FUNC_ERROR); }
672 bool suppressFuncError() const { return flags.isSet(SUPPRESS_FUNC_ERROR); }
673 void setBlockCached() { flags.set(BLOCK_CACHED); }
674 bool isBlockCached() const { return flags.isSet(BLOCK_CACHED); }
675 void clearBlockCached() { flags.clear(BLOCK_CACHED); }
676
677 /**
678 * QoS Value getter
679 * Returns 0 if QoS value was never set (constructor default).
680 *
681 * @return QoS priority value of the packet
682 */
683 inline uint8_t qosValue() const { return _qosValue; }
684
685 /**
686 * QoS Value setter
687 * Interface for setting QoS priority value of the packet.
688 *
689 * @param qos_value QoS priority value
690 */
691 inline void qosValue(const uint8_t qos_value)
692 { _qosValue = qos_value; }
693
694 inline MasterID masterId() const { return req->masterId(); }
695
696 // Network error conditions... encapsulate them as methods since
697 // their encoding keeps changing (from result field to command
698 // field, etc.)
699 void
700 setBadAddress()
701 {
702 assert(isResponse());
703 cmd = MemCmd::BadAddressError;
704 }
705
706 void copyError(Packet *pkt) { assert(pkt->isError()); cmd = pkt->cmd; }
707
708 Addr getAddr() const { assert(flags.isSet(VALID_ADDR)); return addr; }
709 /**
710 * Update the address of this packet mid-transaction. This is used
711 * by the address mapper to change an already set address to a new
712 * one based on the system configuration. It is intended to remap
713 * an existing address, so it asserts that the current address is
714 * valid.
715 */
716 void setAddr(Addr _addr) { assert(flags.isSet(VALID_ADDR)); addr = _addr; }
717
718 unsigned getSize() const { assert(flags.isSet(VALID_SIZE)); return size; }
719
720 Addr getOffset(unsigned int blk_size) const
721 {
722 return getAddr() & Addr(blk_size - 1);
723 }
724
725 Addr getBlockAddr(unsigned int blk_size) const
726 {
727 return getAddr() & ~(Addr(blk_size - 1));
728 }
729
730 bool isSecure() const
731 {
732 assert(flags.isSet(VALID_ADDR));
733 return _isSecure;
734 }
735
736 /**
737 * Accessor function to atomic op.
738 */
739 AtomicOpFunctor *getAtomicOp() const { return req->getAtomicOpFunctor(); }
740 bool isAtomicOp() const { return req->isAtomic(); }
741
742 /**
743 * It has been determined that the SC packet should successfully update
744 * memory. Therefore, convert this SC packet to a normal write.
745 */
746 void
747 convertScToWrite()
748 {
749 assert(isLLSC());
750 assert(isWrite());
751 cmd = MemCmd::WriteReq;
752 }
753
754 /**
755 * When ruby is in use, Ruby will monitor the cache line and the
756 * phys memory should treat LL ops as normal reads.
757 */
758 void
759 convertLlToRead()
760 {
761 assert(isLLSC());
762 assert(isRead());
763 cmd = MemCmd::ReadReq;
764 }
765
766 /**
767 * Constructor. Note that a Request object must be constructed
768 * first, but the Requests's physical address and size fields need
769 * not be valid. The command must be supplied.
770 */
771 Packet(const RequestPtr &_req, MemCmd _cmd)
772 : cmd(_cmd), id((PacketId)_req.get()), req(_req),
773 data(nullptr), addr(0), _isSecure(false), size(0),
774 _qosValue(0), headerDelay(0), snoopDelay(0),
775 payloadDelay(0), senderState(NULL)
776 {
777 if (req->hasPaddr()) {
778 addr = req->getPaddr();
779 flags.set(VALID_ADDR);
780 _isSecure = req->isSecure();
781 }
782 if (req->hasSize()) {
783 size = req->getSize();
784 flags.set(VALID_SIZE);
785 }
786 }
787
788 /**
789 * Alternate constructor if you are trying to create a packet with
790 * a request that is for a whole block, not the address from the
791 * req. this allows for overriding the size/addr of the req.
792 */
793 Packet(const RequestPtr &_req, MemCmd _cmd, int _blkSize, PacketId _id = 0)
794 : cmd(_cmd), id(_id ? _id : (PacketId)_req.get()), req(_req),
795 data(nullptr), addr(0), _isSecure(false),
796 _qosValue(0), headerDelay(0),
797 snoopDelay(0), payloadDelay(0), senderState(NULL)
798 {
799 if (req->hasPaddr()) {
800 addr = req->getPaddr() & ~(_blkSize - 1);
801 flags.set(VALID_ADDR);
802 _isSecure = req->isSecure();
803 }
804 size = _blkSize;
805 flags.set(VALID_SIZE);
806 }
807
808 /**
809 * Alternate constructor for copying a packet. Copy all fields
810 * *except* if the original packet's data was dynamic, don't copy
811 * that, as we can't guarantee that the new packet's lifetime is
812 * less than that of the original packet. In this case the new
813 * packet should allocate its own data.
814 */
815 Packet(const PacketPtr pkt, bool clear_flags, bool alloc_data)
816 : cmd(pkt->cmd), id(pkt->id), req(pkt->req),
817 data(nullptr),
818 addr(pkt->addr), _isSecure(pkt->_isSecure), size(pkt->size),
819 bytesValid(pkt->bytesValid),
820 _qosValue(pkt->qosValue()),
821 headerDelay(pkt->headerDelay),
822 snoopDelay(0),
823 payloadDelay(pkt->payloadDelay),
824 senderState(pkt->senderState)
825 {
826 if (!clear_flags)
827 flags.set(pkt->flags & COPY_FLAGS);
828
829 flags.set(pkt->flags & (VALID_ADDR|VALID_SIZE));
830
831 // should we allocate space for data, or not, the express
832 // snoops do not need to carry any data as they only serve to
833 // co-ordinate state changes
834 if (alloc_data) {
835 // even if asked to allocate data, if the original packet
836 // holds static data, then the sender will not be doing
837 // any memcpy on receiving the response, thus we simply
838 // carry the pointer forward
839 if (pkt->flags.isSet(STATIC_DATA)) {
840 data = pkt->data;
841 flags.set(STATIC_DATA);
842 } else {
843 allocate();
844 }
845 }
846 }
847
848 /**
849 * Generate the appropriate read MemCmd based on the Request flags.
850 */
851 static MemCmd
852 makeReadCmd(const RequestPtr &req)
853 {
854 if (req->isLLSC())
855 return MemCmd::LoadLockedReq;
856 else if (req->isPrefetch())
857 return MemCmd::SoftPFReq;
858 else
859 return MemCmd::ReadReq;
860 }
861
862 /**
863 * Generate the appropriate write MemCmd based on the Request flags.
864 */
865 static MemCmd
866 makeWriteCmd(const RequestPtr &req)
867 {
868 if (req->isLLSC())
869 return MemCmd::StoreCondReq;
870 else if (req->isSwap() || req->isAtomic())
871 return MemCmd::SwapReq;
872 else if (req->isCacheInvalidate()) {
873 return req->isCacheClean() ? MemCmd::CleanInvalidReq :
874 MemCmd::InvalidateReq;
875 } else if (req->isCacheClean()) {
876 return MemCmd::CleanSharedReq;
877 } else
878 return MemCmd::WriteReq;
879 }
880
881 /**
882 * Constructor-like methods that return Packets based on Request objects.
883 * Fine-tune the MemCmd type if it's not a vanilla read or write.
884 */
885 static PacketPtr
886 createRead(const RequestPtr &req)
887 {
888 return new Packet(req, makeReadCmd(req));
889 }
890
891 static PacketPtr
892 createWrite(const RequestPtr &req)
893 {
894 return new Packet(req, makeWriteCmd(req));
895 }
896
897 /**
898 * clean up packet variables
899 */
900 ~Packet()
901 {
902 deleteData();
903 }
904
905 /**
906 * Take a request packet and modify it in place to be suitable for
907 * returning as a response to that request.
908 */
909 void
910 makeResponse()
911 {
912 assert(needsResponse());
913 assert(isRequest());
914 cmd = cmd.responseCommand();
915
916 // responses are never express, even if the snoop that
917 // triggered them was
918 flags.clear(EXPRESS_SNOOP);
919 }
920
921 void
922 makeAtomicResponse()
923 {
924 makeResponse();
925 }
926
927 void
928 makeTimingResponse()
929 {
930 makeResponse();
931 }
932
933 void
934 setFunctionalResponseStatus(bool success)
935 {
936 if (!success) {
937 if (isWrite()) {
938 cmd = MemCmd::FunctionalWriteError;
939 } else {
940 cmd = MemCmd::FunctionalReadError;
941 }
942 }
943 }
944
945 void
946 setSize(unsigned size)
947 {
948 assert(!flags.isSet(VALID_SIZE));
949
950 this->size = size;
951 flags.set(VALID_SIZE);
952 }
953
954
955 public:
956 /**
957 * @{
958 * @name Data accessor mehtods
959 */
960
961 /**
962 * Set the data pointer to the following value that should not be
963 * freed. Static data allows us to do a single memcpy even if
964 * multiple packets are required to get from source to destination
965 * and back. In essence the pointer is set calling dataStatic on
966 * the original packet, and whenever this packet is copied and
967 * forwarded the same pointer is passed on. When a packet
968 * eventually reaches the destination holding the data, it is
969 * copied once into the location originally set. On the way back
970 * to the source, no copies are necessary.
971 */
972 template <typename T>
973 void
974 dataStatic(T *p)
975 {
976 assert(flags.noneSet(STATIC_DATA|DYNAMIC_DATA));
977 data = (PacketDataPtr)p;
978 flags.set(STATIC_DATA);
979 }
980
981 /**
982 * Set the data pointer to the following value that should not be
983 * freed. This version of the function allows the pointer passed
984 * to us to be const. To avoid issues down the line we cast the
985 * constness away, the alternative would be to keep both a const
986 * and non-const data pointer and cleverly choose between
987 * them. Note that this is only allowed for static data.
988 */
989 template <typename T>
990 void
991 dataStaticConst(const T *p)
992 {
993 assert(flags.noneSet(STATIC_DATA|DYNAMIC_DATA));
994 data = const_cast<PacketDataPtr>(p);
995 flags.set(STATIC_DATA);
996 }
997
998 /**
999 * Set the data pointer to a value that should have delete []
1000 * called on it. Dynamic data is local to this packet, and as the
1001 * packet travels from source to destination, forwarded packets
1002 * will allocate their own data. When a packet reaches the final
1003 * destination it will populate the dynamic data of that specific
1004 * packet, and on the way back towards the source, memcpy will be
1005 * invoked in every step where a new packet was created e.g. in
1006 * the caches. Ultimately when the response reaches the source a
1007 * final memcpy is needed to extract the data from the packet
1008 * before it is deallocated.
1009 */
1010 template <typename T>
1011 void
1012 dataDynamic(T *p)
1013 {
1014 assert(flags.noneSet(STATIC_DATA|DYNAMIC_DATA));
1015 data = (PacketDataPtr)p;
1016 flags.set(DYNAMIC_DATA);
1017 }
1018
1019 /**
1020 * get a pointer to the data ptr.
1021 */
1022 template <typename T>
1023 T*
1024 getPtr()
1025 {
1026 assert(flags.isSet(STATIC_DATA|DYNAMIC_DATA));
1027 return (T*)data;
1028 }
1029
1030 template <typename T>
1031 const T*
1032 getConstPtr() const
1033 {
1034 assert(flags.isSet(STATIC_DATA|DYNAMIC_DATA));
1035 return (const T*)data;
1036 }
1037
1038 /**
1039 * Get the data in the packet byte swapped from big endian to
1040 * host endian.
1041 */
1042 template <typename T>
1043 T getBE() const;
1044
1045 /**
1046 * Get the data in the packet byte swapped from little endian to
1047 * host endian.
1048 */
1049 template <typename T>
1050 T getLE() const;
1051
1052 /**
1053 * Get the data in the packet byte swapped from the specified
1054 * endianness.
1055 */
1056 template <typename T>
1057 T get(ByteOrder endian) const;
1058
1059#if THE_ISA != NULL_ISA
1060 /**
1061 * Get the data in the packet byte swapped from guest to host
1062 * endian.
1063 */
1064 template <typename T>
|