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gem5/src/mem/packet.hh
Giacomo Gabrielli c58cb8c9db cpu,mem: Add support for partial loads/stores and wide mem. accesses 
This changeset adds support for partial (or masked) loads/stores, i.e.
loads/stores that can disable accesses to individual bytes within the
target address range.  In addition, this changeset extends the code to
crack memory accesses across most CPU models (TimingSimpleCPU still
TBD), so that arbitrarily wide memory accesses are supported.  These
changes are required for supporting ISAs with wide vectors.

Additional authors:
- Gabor Dozsa <gabor.dozsa@arm.com>
- Tiago Muck <tiago.muck@arm.com>

Change-Id: Ibad33541c258ad72925c0b1d5abc3e5e8bf92d92
Signed-off-by: Giacomo Gabrielli <giacomo.gabrielli@arm.com>
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/13518
Tested-by: kokoro <noreply+kokoro@google.com>
Reviewed-by: Nikos Nikoleris <nikos.nikoleris@arm.com>
Maintainer: Nikos Nikoleris <nikos.nikoleris@arm.com>
2019-05-11 12:48:58 +00:00

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/*
* Copyright (c) 2012-2019 ARM Limited
* All rights reserved
*
* The license below extends only to copyright in the software and shall
* not be construed as granting a license to any other intellectual
* property including but not limited to intellectual property relating
* to a hardware implementation of the functionality of the software
* licensed hereunder. You may use the software subject to the license
* terms below provided that you ensure that this notice is replicated
* unmodified and in its entirety in all distributions of the software,
* modified or unmodified, in source code or in binary form.
*
* Copyright (c) 2006 The Regents of The University of Michigan
* Copyright (c) 2010,2015 Advanced Micro Devices, Inc.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are
* met: redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer;
* redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution;
* neither the name of the copyright holders nor the names of its
* contributors may be used to endorse or promote products derived from
* this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
* OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*
* Authors: Ron Dreslinski
* Steve Reinhardt
* Ali Saidi
* Andreas Hansson
* Nikos Nikoleris
*/
/**
* @file
* Declaration of the Packet class.
*/
#ifndef __MEM_PACKET_HH__
#define __MEM_PACKET_HH__
#include <bitset>
#include <cassert>
#include <list>
#include "base/addr_range.hh"
#include "base/cast.hh"
#include "base/compiler.hh"
#include "base/flags.hh"
#include "base/logging.hh"
#include "base/printable.hh"
#include "base/types.hh"
#include "config/the_isa.hh"
#include "mem/request.hh"
#include "sim/core.hh"
class Packet;
typedef Packet *PacketPtr;
typedef uint8_t* PacketDataPtr;
typedef std::list<PacketPtr> PacketList;
typedef uint64_t PacketId;
class MemCmd
{
friend class Packet;
public:
/**
* List of all commands associated with a packet.
*/
enum Command
{
InvalidCmd,
ReadReq,
ReadResp,
ReadRespWithInvalidate,
WriteReq,
WriteResp,
WritebackDirty,
WritebackClean,
WriteClean, // writes dirty data below without evicting
CleanEvict,
SoftPFReq,
SoftPFExReq,
HardPFReq,
SoftPFResp,
HardPFResp,
WriteLineReq,
UpgradeReq,
SCUpgradeReq, // Special "weak" upgrade for StoreCond
UpgradeResp,
SCUpgradeFailReq, // Failed SCUpgradeReq in MSHR (never sent)
UpgradeFailResp, // Valid for SCUpgradeReq only
ReadExReq,
ReadExResp,
ReadCleanReq,
ReadSharedReq,
LoadLockedReq,
StoreCondReq,
StoreCondFailReq, // Failed StoreCondReq in MSHR (never sent)
StoreCondResp,
SwapReq,
SwapResp,
MessageReq,
MessageResp,
MemFenceReq,
MemFenceResp,
CleanSharedReq,
CleanSharedResp,
CleanInvalidReq,
CleanInvalidResp,
// Error responses
// @TODO these should be classified as responses rather than
// requests; coding them as requests initially for backwards
// compatibility
InvalidDestError, // packet dest field invalid
BadAddressError, // memory address invalid
FunctionalReadError, // unable to fulfill functional read
FunctionalWriteError, // unable to fulfill functional write
// Fake simulator-only commands
PrintReq, // Print state matching address
FlushReq, //request for a cache flush
InvalidateReq, // request for address to be invalidated
InvalidateResp,
NUM_MEM_CMDS
};
private:
/**
* List of command attributes.
*/
enum Attribute
{
IsRead, //!< Data flows from responder to requester
IsWrite, //!< Data flows from requester to responder
IsUpgrade,
IsInvalidate,
IsClean, //!< Cleans any existing dirty blocks
NeedsWritable, //!< Requires writable copy to complete in-cache
IsRequest, //!< Issued by requester
IsResponse, //!< Issue by responder
NeedsResponse, //!< Requester needs response from target
IsEviction,
IsSWPrefetch,
IsHWPrefetch,
IsLlsc, //!< Alpha/MIPS LL or SC access
HasData, //!< There is an associated payload
IsError, //!< Error response
IsPrint, //!< Print state matching address (for debugging)
IsFlush, //!< Flush the address from caches
FromCache, //!< Request originated from a caching agent
NUM_COMMAND_ATTRIBUTES
};
/**
* Structure that defines attributes and other data associated
* with a Command.
*/
struct CommandInfo
{
/// Set of attribute flags.
const std::bitset<NUM_COMMAND_ATTRIBUTES> attributes;
/// Corresponding response for requests; InvalidCmd if no
/// response is applicable.
const Command response;
/// String representation (for printing)
const std::string str;
};
/// Array to map Command enum to associated info.
static const CommandInfo commandInfo[];
private:
Command cmd;
bool
testCmdAttrib(MemCmd::Attribute attrib) const
{
return commandInfo[cmd].attributes[attrib] != 0;
}
public:
bool isRead() const { return testCmdAttrib(IsRead); }
bool isWrite() const { return testCmdAttrib(IsWrite); }
bool isUpgrade() const { return testCmdAttrib(IsUpgrade); }
bool isRequest() const { return testCmdAttrib(IsRequest); }
bool isResponse() const { return testCmdAttrib(IsResponse); }
bool needsWritable() const { return testCmdAttrib(NeedsWritable); }
bool needsResponse() const { return testCmdAttrib(NeedsResponse); }
bool isInvalidate() const { return testCmdAttrib(IsInvalidate); }
bool isEviction() const { return testCmdAttrib(IsEviction); }
bool isClean() const { return testCmdAttrib(IsClean); }
bool fromCache() const { return testCmdAttrib(FromCache); }
/**
* A writeback is an eviction that carries data.
*/
bool isWriteback() const { return testCmdAttrib(IsEviction) &&
testCmdAttrib(HasData); }
/**
* Check if this particular packet type carries payload data. Note
* that this does not reflect if the data pointer of the packet is
* valid or not.
*/
bool hasData() const { return testCmdAttrib(HasData); }
bool isLLSC() const { return testCmdAttrib(IsLlsc); }
bool isSWPrefetch() const { return testCmdAttrib(IsSWPrefetch); }
bool isHWPrefetch() const { return testCmdAttrib(IsHWPrefetch); }
bool isPrefetch() const { return testCmdAttrib(IsSWPrefetch) ||
testCmdAttrib(IsHWPrefetch); }
bool isError() const { return testCmdAttrib(IsError); }
bool isPrint() const { return testCmdAttrib(IsPrint); }
bool isFlush() const { return testCmdAttrib(IsFlush); }
Command
responseCommand() const
{
return commandInfo[cmd].response;
}
/// Return the string to a cmd given by idx.
const std::string &toString() const { return commandInfo[cmd].str; }
int toInt() const { return (int)cmd; }
MemCmd(Command _cmd) : cmd(_cmd) { }
MemCmd(int _cmd) : cmd((Command)_cmd) { }
MemCmd() : cmd(InvalidCmd) { }
bool operator==(MemCmd c2) const { return (cmd == c2.cmd); }
bool operator!=(MemCmd c2) const { return (cmd != c2.cmd); }
};
/**
* A Packet is used to encapsulate a transfer between two objects in
* the memory system (e.g., the L1 and L2 cache). (In contrast, a
* single Request travels all the way from the requester to the
* ultimate destination and back, possibly being conveyed by several
* different Packets along the way.)
*/
class Packet : public Printable
{
public:
typedef uint32_t FlagsType;
typedef ::Flags<FlagsType> Flags;
private:
enum : FlagsType {
// Flags to transfer across when copying a packet
COPY_FLAGS = 0x0000003F,
// Flags that are used to create reponse packets
RESPONDER_FLAGS = 0x00000009,
// Does this packet have sharers (which means it should not be
// considered writable) or not. See setHasSharers below.
HAS_SHARERS = 0x00000001,
// Special control flags
/// Special timing-mode atomic snoop for multi-level coherence.
EXPRESS_SNOOP = 0x00000002,
/// Allow a responding cache to inform the cache hierarchy
/// that it had a writable copy before responding. See
/// setResponderHadWritable below.
RESPONDER_HAD_WRITABLE = 0x00000004,
// Snoop co-ordination flag to indicate that a cache is
// responding to a snoop. See setCacheResponding below.
CACHE_RESPONDING = 0x00000008,
// The writeback/writeclean should be propagated further
// downstream by the receiver
WRITE_THROUGH = 0x00000010,
// Response co-ordination flag for cache maintenance
// operations
SATISFIED = 0x00000020,
/// Are the 'addr' and 'size' fields valid?
VALID_ADDR = 0x00000100,
VALID_SIZE = 0x00000200,
/// Is the data pointer set to a value that shouldn't be freed
/// when the packet is destroyed?
STATIC_DATA = 0x00001000,
/// The data pointer points to a value that should be freed when
/// the packet is destroyed. The pointer is assumed to be pointing
/// to an array, and delete [] is consequently called
DYNAMIC_DATA = 0x00002000,
/// suppress the error if this packet encounters a functional
/// access failure.
SUPPRESS_FUNC_ERROR = 0x00008000,
// Signal block present to squash prefetch and cache evict packets
// through express snoop flag
BLOCK_CACHED = 0x00010000
};
Flags flags;
public:
typedef MemCmd::Command Command;
/// The command field of the packet.
MemCmd cmd;
const PacketId id;
/// A pointer to the original request.
RequestPtr req;
private:
/**
* A pointer to the data being transferred. It can be different
* sizes at each level of the hierarchy so it belongs to the
* packet, not request. This may or may not be populated when a
* responder receives the packet. If not populated memory should
* be allocated.
*/
PacketDataPtr data;
/// The address of the request. This address could be virtual or
/// physical, depending on the system configuration.
Addr addr;
/// True if the request targets the secure memory space.
bool _isSecure;
/// The size of the request or transfer.
unsigned size;
/**
* Track the bytes found that satisfy a functional read.
*/
std::vector<bool> bytesValid;
// Quality of Service priority value
uint8_t _qosValue;
public:
/**
* The extra delay from seeing the packet until the header is
* transmitted. This delay is used to communicate the crossbar
* forwarding latency to the neighbouring object (e.g. a cache)
* that actually makes the packet wait. As the delay is relative,
* a 32-bit unsigned should be sufficient.
*/
uint32_t headerDelay;
/**
* Keep track of the extra delay incurred by snooping upwards
* before sending a request down the memory system. This is used
* by the coherent crossbar to account for the additional request
* delay.
*/
uint32_t snoopDelay;
/**
* The extra pipelining delay from seeing the packet until the end of
* payload is transmitted by the component that provided it (if
* any). This includes the header delay. Similar to the header
* delay, this is used to make up for the fact that the
* crossbar does not make the packet wait. As the delay is
* relative, a 32-bit unsigned should be sufficient.
*/
uint32_t payloadDelay;
/**
* A virtual base opaque structure used to hold state associated
* with the packet (e.g., an MSHR), specific to a SimObject that
* sees the packet. A pointer to this state is returned in the
* packet's response so that the SimObject in question can quickly
* look up the state needed to process it. A specific subclass
* would be derived from this to carry state specific to a
* particular sending device.
*
* As multiple SimObjects may add their SenderState throughout the
* memory system, the SenderStates create a stack, where a
* SimObject can add a new Senderstate, as long as the
* predecessing SenderState is restored when the response comes
* back. For this reason, the predecessor should always be
* populated with the current SenderState of a packet before
* modifying the senderState field in the request packet.
*/
struct SenderState
{
SenderState* predecessor;
SenderState() : predecessor(NULL) {}
virtual ~SenderState() {}
};
/**
* Object used to maintain state of a PrintReq. The senderState
* field of a PrintReq should always be of this type.
*/
class PrintReqState : public SenderState
{
private:
/**
* An entry in the label stack.
*/
struct LabelStackEntry
{
const std::string label;
std::string *prefix;
bool labelPrinted;
LabelStackEntry(const std::string &_label, std::string *_prefix);
};
typedef std::list<LabelStackEntry> LabelStack;
LabelStack labelStack;
std::string *curPrefixPtr;
public:
std::ostream &os;
const int verbosity;
PrintReqState(std::ostream &os, int verbosity = 0);
~PrintReqState();
/**
* Returns the current line prefix.
*/
const std::string &curPrefix() { return *curPrefixPtr; }
/**
* Push a label onto the label stack, and prepend the given
* prefix string onto the current prefix. Labels will only be
* printed if an object within the label's scope is printed.
*/
void pushLabel(const std::string &lbl,
const std::string &prefix = " ");
/**
* Pop a label off the label stack.
*/
void popLabel();
/**
* Print all of the pending unprinted labels on the
* stack. Called by printObj(), so normally not called by
* users unless bypassing printObj().
*/
void printLabels();
/**
* Print a Printable object to os, because it matched the
* address on a PrintReq.
*/
void printObj(Printable *obj);
};
/**
* This packet's sender state. Devices should use dynamic_cast<>
* to cast to the state appropriate to the sender. The intent of
* this variable is to allow a device to attach extra information
* to a request. A response packet must return the sender state
* that was attached to the original request (even if a new packet
* is created).
*/
SenderState *senderState;
/**
* Push a new sender state to the packet and make the current
* sender state the predecessor of the new one. This should be
* prefered over direct manipulation of the senderState member
* variable.
*
* @param sender_state SenderState to push at the top of the stack
*/
void pushSenderState(SenderState *sender_state);
/**
* Pop the top of the state stack and return a pointer to it. This
* assumes the current sender state is not NULL. This should be
* preferred over direct manipulation of the senderState member
* variable.
*
* @return The current top of the stack
*/
SenderState *popSenderState();
/**
* Go through the sender state stack and return the first instance
* that is of type T (as determined by a dynamic_cast). If there
* is no sender state of type T, NULL is returned.
*
* @return The topmost state of type T
*/
template <typename T>
T * findNextSenderState() const
{
T *t = NULL;
SenderState* sender_state = senderState;
while (t == NULL && sender_state != NULL) {
t = dynamic_cast<T*>(sender_state);
sender_state = sender_state->predecessor;
}
return t;
}
/// Return the string name of the cmd field (for debugging and
/// tracing).
const std::string &cmdString() const { return cmd.toString(); }
/// Return the index of this command.
inline int cmdToIndex() const { return cmd.toInt(); }
bool isRead() const { return cmd.isRead(); }
bool isWrite() const { return cmd.isWrite(); }
bool isUpgrade() const { return cmd.isUpgrade(); }
bool isRequest() const { return cmd.isRequest(); }
bool isResponse() const { return cmd.isResponse(); }
bool needsWritable() const
{
// we should never check if a response needsWritable, the
// request has this flag, and for a response we should rather
// look at the hasSharers flag (if not set, the response is to
// be considered writable)
assert(isRequest());
return cmd.needsWritable();
}
bool needsResponse() const { return cmd.needsResponse(); }
bool isInvalidate() const { return cmd.isInvalidate(); }
bool isEviction() const { return cmd.isEviction(); }
bool isClean() const { return cmd.isClean(); }
bool fromCache() const { return cmd.fromCache(); }
bool isWriteback() const { return cmd.isWriteback(); }
bool hasData() const { return cmd.hasData(); }
bool hasRespData() const
{
MemCmd resp_cmd = cmd.responseCommand();
return resp_cmd.hasData();
}
bool isLLSC() const { return cmd.isLLSC(); }
bool isError() const { return cmd.isError(); }
bool isPrint() const { return cmd.isPrint(); }
bool isFlush() const { return cmd.isFlush(); }
bool isWholeLineWrite(unsigned blk_size)
{
return (cmd == MemCmd::WriteReq || cmd == MemCmd::WriteLineReq) &&
getOffset(blk_size) == 0 && getSize() == blk_size;
}
//@{
/// Snoop flags
/**
* Set the cacheResponding flag. This is used by the caches to
* signal another cache that they are responding to a request. A
* cache will only respond to snoops if it has the line in either
* Modified or Owned state. Note that on snoop hits we always pass
* the line as Modified and never Owned. In the case of an Owned
* line we proceed to invalidate all other copies.
*
* On a cache fill (see Cache::handleFill), we check hasSharers
* first, ignoring the cacheResponding flag if hasSharers is set.
* A line is consequently allocated as:
*
* hasSharers cacheResponding state
* true false Shared
* true true Shared
* false false Exclusive
* false true Modified
*/
void setCacheResponding()
{
assert(isRequest());
assert(!flags.isSet(CACHE_RESPONDING));
flags.set(CACHE_RESPONDING);
}
bool cacheResponding() const { return flags.isSet(CACHE_RESPONDING); }
/**
* On fills, the hasSharers flag is used by the caches in
* combination with the cacheResponding flag, as clarified
* above. If the hasSharers flag is not set, the packet is passing
* writable. Thus, a response from a memory passes the line as
* writable by default.
*
* The hasSharers flag is also used by upstream caches to inform a
* downstream cache that they have the block (by calling
* setHasSharers on snoop request packets that hit in upstream
* cachs tags or MSHRs). If the snoop packet has sharers, a
* downstream cache is prevented from passing a dirty line upwards
* if it was not explicitly asked for a writable copy. See
* Cache::satisfyCpuSideRequest.
*
* The hasSharers flag is also used on writebacks, in
* combination with the WritbackClean or WritebackDirty commands,
* to allocate the block downstream either as:
*
* command hasSharers state
* WritebackDirty false Modified
* WritebackDirty true Owned
* WritebackClean false Exclusive
* WritebackClean true Shared
*/
void setHasSharers() { flags.set(HAS_SHARERS); }
bool hasSharers() const { return flags.isSet(HAS_SHARERS); }
//@}
/**
* The express snoop flag is used for two purposes. Firstly, it is
* used to bypass flow control for normal (non-snoop) requests
* going downstream in the memory system. In cases where a cache
* is responding to a snoop from another cache (it had a dirty
* line), but the line is not writable (and there are possibly
* other copies), the express snoop flag is set by the downstream
* cache to invalidate all other copies in zero time. Secondly,
* the express snoop flag is also set to be able to distinguish
* snoop packets that came from a downstream cache, rather than
* snoop packets from neighbouring caches.
*/
void setExpressSnoop() { flags.set(EXPRESS_SNOOP); }
bool isExpressSnoop() const { return flags.isSet(EXPRESS_SNOOP); }
/**
* On responding to a snoop request (which only happens for
* Modified or Owned lines), make sure that we can transform an
* Owned response to a Modified one. If this flag is not set, the
* responding cache had the line in the Owned state, and there are
* possibly other Shared copies in the memory system. A downstream
* cache helps in orchestrating the invalidation of these copies
* by sending out the appropriate express snoops.
*/
void setResponderHadWritable()
{
assert(cacheResponding());
assert(!responderHadWritable());
flags.set(RESPONDER_HAD_WRITABLE);
}
bool responderHadWritable() const
{ return flags.isSet(RESPONDER_HAD_WRITABLE); }
/**
* Copy the reponse flags from an input packet to this packet. The
* reponse flags determine whether a responder has been found and
* the state at which the block will be at the destination.
*
* @pkt The packet that we will copy flags from
*/
void copyResponderFlags(const PacketPtr pkt);
/**
* A writeback/writeclean cmd gets propagated further downstream
* by the receiver when the flag is set.
*/
void setWriteThrough()
{
assert(cmd.isWrite() &&
(cmd.isEviction() || cmd == MemCmd::WriteClean));
flags.set(WRITE_THROUGH);
}
void clearWriteThrough() { flags.clear(WRITE_THROUGH); }
bool writeThrough() const { return flags.isSet(WRITE_THROUGH); }
/**
* Set when a request hits in a cache and the cache is not going
* to respond. This is used by the crossbar to coordinate
* responses for cache maintenance operations.
*/
void setSatisfied()
{
assert(cmd.isClean());
assert(!flags.isSet(SATISFIED));
flags.set(SATISFIED);
}
bool satisfied() const { return flags.isSet(SATISFIED); }
void setSuppressFuncError() { flags.set(SUPPRESS_FUNC_ERROR); }
bool suppressFuncError() const { return flags.isSet(SUPPRESS_FUNC_ERROR); }
void setBlockCached() { flags.set(BLOCK_CACHED); }
bool isBlockCached() const { return flags.isSet(BLOCK_CACHED); }
void clearBlockCached() { flags.clear(BLOCK_CACHED); }
/**
* QoS Value getter
* Returns 0 if QoS value was never set (constructor default).
*
* @return QoS priority value of the packet
*/
inline uint8_t qosValue() const { return _qosValue; }
/**
* QoS Value setter
* Interface for setting QoS priority value of the packet.
*
* @param qos_value QoS priority value
*/
inline void qosValue(const uint8_t qos_value)
{ _qosValue = qos_value; }
inline MasterID masterId() const { return req->masterId(); }
// Network error conditions... encapsulate them as methods since
// their encoding keeps changing (from result field to command
// field, etc.)
void
setBadAddress()
{
assert(isResponse());
cmd = MemCmd::BadAddressError;
}
void copyError(Packet *pkt) { assert(pkt->isError()); cmd = pkt->cmd; }
Addr getAddr() const { assert(flags.isSet(VALID_ADDR)); return addr; }
/**
* Update the address of this packet mid-transaction. This is used
* by the address mapper to change an already set address to a new
* one based on the system configuration. It is intended to remap
* an existing address, so it asserts that the current address is
* valid.
*/
void setAddr(Addr _addr) { assert(flags.isSet(VALID_ADDR)); addr = _addr; }
unsigned getSize() const { assert(flags.isSet(VALID_SIZE)); return size; }
/**
* Get address range to which this packet belongs.
*
* @return Address range of this packet.
*/
AddrRange getAddrRange() const;
Addr getOffset(unsigned int blk_size) const
{
return getAddr() & Addr(blk_size - 1);
}
Addr getBlockAddr(unsigned int blk_size) const
{
return getAddr() & ~(Addr(blk_size - 1));
}
bool isSecure() const
{
assert(flags.isSet(VALID_ADDR));
return _isSecure;
}
/**
* Accessor function to atomic op.
*/
AtomicOpFunctor *getAtomicOp() const { return req->getAtomicOpFunctor(); }
bool isAtomicOp() const { return req->isAtomic(); }
/**
* It has been determined that the SC packet should successfully update
* memory. Therefore, convert this SC packet to a normal write.
*/
void
convertScToWrite()
{
assert(isLLSC());
assert(isWrite());
cmd = MemCmd::WriteReq;
}
/**
* When ruby is in use, Ruby will monitor the cache line and the
* phys memory should treat LL ops as normal reads.
*/
void
convertLlToRead()
{
assert(isLLSC());
assert(isRead());
cmd = MemCmd::ReadReq;
}
/**
* Constructor. Note that a Request object must be constructed
* first, but the Requests's physical address and size fields need
* not be valid. The command must be supplied.
*/
Packet(const RequestPtr &_req, MemCmd _cmd)
: cmd(_cmd), id((PacketId)_req.get()), req(_req),
data(nullptr), addr(0), _isSecure(false), size(0),
_qosValue(0), headerDelay(0), snoopDelay(0),
payloadDelay(0), senderState(NULL)
{
if (req->hasPaddr()) {
addr = req->getPaddr();
flags.set(VALID_ADDR);
_isSecure = req->isSecure();
}
if (req->hasSize()) {
size = req->getSize();
flags.set(VALID_SIZE);
}
}
/**
* Alternate constructor if you are trying to create a packet with
* a request that is for a whole block, not the address from the
* req. this allows for overriding the size/addr of the req.
*/
Packet(const RequestPtr &_req, MemCmd _cmd, int _blkSize, PacketId _id = 0)
: cmd(_cmd), id(_id ? _id : (PacketId)_req.get()), req(_req),
data(nullptr), addr(0), _isSecure(false),
_qosValue(0), headerDelay(0),
snoopDelay(0), payloadDelay(0), senderState(NULL)
{
if (req->hasPaddr()) {
addr = req->getPaddr() & ~(_blkSize - 1);
flags.set(VALID_ADDR);
_isSecure = req->isSecure();
}
size = _blkSize;
flags.set(VALID_SIZE);
}
/**
* Alternate constructor for copying a packet. Copy all fields
* *except* if the original packet's data was dynamic, don't copy
* that, as we can't guarantee that the new packet's lifetime is
* less than that of the original packet. In this case the new
* packet should allocate its own data.
*/
Packet(const PacketPtr pkt, bool clear_flags, bool alloc_data)
: cmd(pkt->cmd), id(pkt->id), req(pkt->req),
data(nullptr),
addr(pkt->addr), _isSecure(pkt->_isSecure), size(pkt->size),
bytesValid(pkt->bytesValid),
_qosValue(pkt->qosValue()),
headerDelay(pkt->headerDelay),
snoopDelay(0),
payloadDelay(pkt->payloadDelay),
senderState(pkt->senderState)
{
if (!clear_flags)
flags.set(pkt->flags & COPY_FLAGS);
flags.set(pkt->flags & (VALID_ADDR|VALID_SIZE));
// should we allocate space for data, or not, the express
// snoops do not need to carry any data as they only serve to
// co-ordinate state changes
if (alloc_data) {
// even if asked to allocate data, if the original packet
// holds static data, then the sender will not be doing
// any memcpy on receiving the response, thus we simply
// carry the pointer forward
if (pkt->flags.isSet(STATIC_DATA)) {
data = pkt->data;
flags.set(STATIC_DATA);
} else {
allocate();
}
}
}
/**
* Generate the appropriate read MemCmd based on the Request flags.
*/
static MemCmd
makeReadCmd(const RequestPtr &req)
{
if (req->isLLSC())
return MemCmd::LoadLockedReq;
else if (req->isPrefetchEx())
return MemCmd::SoftPFExReq;
else if (req->isPrefetch())
return MemCmd::SoftPFReq;
else
return MemCmd::ReadReq;
}
/**
* Generate the appropriate write MemCmd based on the Request flags.
*/
static MemCmd
makeWriteCmd(const RequestPtr &req)
{
if (req->isLLSC())
return MemCmd::StoreCondReq;
else if (req->isSwap() || req->isAtomic())
return MemCmd::SwapReq;
else if (req->isCacheInvalidate()) {
return req->isCacheClean() ? MemCmd::CleanInvalidReq :
MemCmd::InvalidateReq;
} else if (req->isCacheClean()) {
return MemCmd::CleanSharedReq;
} else
return MemCmd::WriteReq;
}
/**
* Constructor-like methods that return Packets based on Request objects.
* Fine-tune the MemCmd type if it's not a vanilla read or write.
*/
static PacketPtr
createRead(const RequestPtr &req)
{
return new Packet(req, makeReadCmd(req));
}
static PacketPtr
createWrite(const RequestPtr &req)
{
return new Packet(req, makeWriteCmd(req));
}
/**
* clean up packet variables
*/
~Packet()
{
deleteData();
}
/**
* Take a request packet and modify it in place to be suitable for
* returning as a response to that request.
*/
void
makeResponse()
{
assert(needsResponse());
assert(isRequest());
cmd = cmd.responseCommand();
// responses are never express, even if the snoop that
// triggered them was
flags.clear(EXPRESS_SNOOP);
}
void
makeAtomicResponse()
{
makeResponse();
}
void
makeTimingResponse()
{
makeResponse();
}
void
setFunctionalResponseStatus(bool success)
{
if (!success) {
if (isWrite()) {
cmd = MemCmd::FunctionalWriteError;
} else {
cmd = MemCmd::FunctionalReadError;
}
}
}
void
setSize(unsigned size)
{
assert(!flags.isSet(VALID_SIZE));
this->size = size;
flags.set(VALID_SIZE);
}
/**
* Check if packet corresponds to a given block-aligned address and
* address space.
*
* @param addr The address to compare against.
* @param is_secure Whether addr belongs to the secure address space.
* @param blk_size Block size in bytes.
* @return Whether packet matches description.
*/
bool matchBlockAddr(const Addr addr, const bool is_secure,
const int blk_size) const;
/**
* Check if this packet refers to the same block-aligned address and
* address space as another packet.
*
* @param pkt The packet to compare against.
* @param blk_size Block size in bytes.
* @return Whether packet matches description.
*/
bool matchBlockAddr(const PacketPtr pkt, const int blk_size) const;
/**
* Check if packet corresponds to a given address and address space.
*
* @param addr The address to compare against.
* @param is_secure Whether addr belongs to the secure address space.
* @return Whether packet matches description.
*/
bool matchAddr(const Addr addr, const bool is_secure) const;
/**
* Check if this packet refers to the same address and address space as
* another packet.
*
* @param pkt The packet to compare against.
* @return Whether packet matches description.
*/
bool matchAddr(const PacketPtr pkt) const;
public:
/**
* @{
* @name Data accessor mehtods
*/
/**
* Set the data pointer to the following value that should not be
* freed. Static data allows us to do a single memcpy even if
* multiple packets are required to get from source to destination
* and back. In essence the pointer is set calling dataStatic on
* the original packet, and whenever this packet is copied and
* forwarded the same pointer is passed on. When a packet
* eventually reaches the destination holding the data, it is
* copied once into the location originally set. On the way back
* to the source, no copies are necessary.
*/
template <typename T>
void
dataStatic(T *p)
{
assert(flags.noneSet(STATIC_DATA|DYNAMIC_DATA));
data = (PacketDataPtr)p;
flags.set(STATIC_DATA);
}
/**
* Set the data pointer to the following value that should not be
* freed. This version of the function allows the pointer passed
* to us to be const. To avoid issues down the line we cast the
* constness away, the alternative would be to keep both a const
* and non-const data pointer and cleverly choose between
* them. Note that this is only allowed for static data.
*/
template <typename T>
void
dataStaticConst(const T *p)
{
assert(flags.noneSet(STATIC_DATA|DYNAMIC_DATA));
data = const_cast<PacketDataPtr>(p);
flags.set(STATIC_DATA);
}
/**
* Set the data pointer to a value that should have delete []
* called on it. Dynamic data is local to this packet, and as the
* packet travels from source to destination, forwarded packets
* will allocate their own data. When a packet reaches the final
* destination it will populate the dynamic data of that specific
* packet, and on the way back towards the source, memcpy will be
* invoked in every step where a new packet was created e.g. in
* the caches. Ultimately when the response reaches the source a
* final memcpy is needed to extract the data from the packet
* before it is deallocated.
*/
template <typename T>
void
dataDynamic(T *p)
{
assert(flags.noneSet(STATIC_DATA|DYNAMIC_DATA));
data = (PacketDataPtr)p;
flags.set(DYNAMIC_DATA);
}
/**
* get a pointer to the data ptr.
*/
template <typename T>
T*
getPtr()
{
assert(flags.isSet(STATIC_DATA|DYNAMIC_DATA));
assert(!isMaskedWrite());
return (T*)data;
}
template <typename T>
const T*
getConstPtr() const
{
assert(flags.isSet(STATIC_DATA|DYNAMIC_DATA));
return (const T*)data;
}
/**
* Get the data in the packet byte swapped from big endian to
* host endian.
*/
template <typename T>
T getBE() const;
/**
* Get the data in the packet byte swapped from little endian to
* host endian.
*/
template <typename T>
T getLE() const;
/**
* Get the data in the packet byte swapped from the specified
* endianness.
*/
template <typename T>
T get(ByteOrder endian) const;
#if THE_ISA != NULL_ISA
/**
* Get the data in the packet byte swapped from guest to host
* endian.
*/
template <typename T>
T get() const
M5_DEPRECATED_MSG("The memory system should be ISA independent.");
#endif
/** Set the value in the data pointer to v as big endian. */
template <typename T>
void setBE(T v);
/** Set the value in the data pointer to v as little endian. */
template <typename T>
void setLE(T v);
/**
* Set the value in the data pointer to v using the specified
* endianness.
*/
template <typename T>
void set(T v, ByteOrder endian);
#if THE_ISA != NULL_ISA
/** Set the value in the data pointer to v as guest endian. */
template <typename T>
void set(T v)
M5_DEPRECATED_MSG("The memory system should be ISA independent.");
#endif
/**
* Get the data in the packet byte swapped from the specified
* endianness and zero-extended to 64 bits.
*/
uint64_t getUintX(ByteOrder endian) const;
/**
* Set the value in the word w after truncating it to the length
* of the packet and then byteswapping it to the desired
* endianness.
*/
void setUintX(uint64_t w, ByteOrder endian);
/**
* Copy data into the packet from the provided pointer.
*/
void
setData(const uint8_t *p)
{
// we should never be copying data onto itself, which means we
// must idenfity packets with static data, as they carry the
// same pointer from source to destination and back
assert(p != getPtr<uint8_t>() || flags.isSet(STATIC_DATA));
if (p != getPtr<uint8_t>()) {
// for packet with allocated dynamic data, we copy data from
// one to the other, e.g. a forwarded response to a response
std::memcpy(getPtr<uint8_t>(), p, getSize());
}
}
/**
* Copy data into the packet from the provided block pointer,
* which is aligned to the given block size.
*/
void
setDataFromBlock(const uint8_t *blk_data, int blkSize)
{
setData(blk_data + getOffset(blkSize));
}
/**
* Copy data from the packet to the memory at the provided pointer.
* @param p Pointer to which data will be copied.
*/
void
writeData(uint8_t *p) const
{
if (!isMaskedWrite()) {
std::memcpy(p, getConstPtr<uint8_t>(), getSize());
} else {
assert(req->getByteEnable().size() == getSize());
// Write only the enabled bytes
const uint8_t *base = getConstPtr<uint8_t>();
for (int i = 0; i < getSize(); i++) {
if (req->getByteEnable()[i]) {
p[i] = *(base + i);
}
// Disabled bytes stay untouched
}
}
}
/**
* Copy data from the packet to the provided block pointer, which
* is aligned to the given block size.
* @param blk_data Pointer to block to which data will be copied.
* @param blkSize Block size in bytes.
*/
void
writeDataToBlock(uint8_t *blk_data, int blkSize) const
{
writeData(blk_data + getOffset(blkSize));
}
/**
* delete the data pointed to in the data pointer. Ok to call to
* matter how data was allocted.
*/
void
deleteData()
{
if (flags.isSet(DYNAMIC_DATA))
delete [] data;
flags.clear(STATIC_DATA|DYNAMIC_DATA);
data = NULL;
}
/** Allocate memory for the packet. */
void
allocate()
{
// if either this command or the response command has a data
// payload, actually allocate space
if (hasData() || hasRespData()) {
assert(flags.noneSet(STATIC_DATA|DYNAMIC_DATA));
flags.set(DYNAMIC_DATA);
data = new uint8_t[getSize()];
}
}
/** @} */
/** Get the data in the packet without byte swapping. */
template <typename T>
T getRaw() const;
/** Set the value in the data pointer to v without byte swapping. */
template <typename T>
void setRaw(T v);
public:
/**
* Check a functional request against a memory value stored in
* another packet (i.e. an in-transit request or
* response). Returns true if the current packet is a read, and
* the other packet provides the data, which is then copied to the
* current packet. If the current packet is a write, and the other
* packet intersects this one, then we update the data
* accordingly.
*/
bool
trySatisfyFunctional(PacketPtr other)
{
if (other->isMaskedWrite()) {
// Do not forward data if overlapping with a masked write
if (_isSecure == other->isSecure() &&
getAddr() <= (other->getAddr() + other->getSize() - 1) &&
other->getAddr() <= (getAddr() + getSize() - 1)) {
warn("Trying to check against a masked write, skipping."
" (addr: 0x%x, other addr: 0x%x)", getAddr(),
other->getAddr());
}
return false;
}
// all packets that are carrying a payload should have a valid
// data pointer
return trySatisfyFunctional(other, other->getAddr(), other->isSecure(),
other->getSize(),
other->hasData() ?
other->getPtr<uint8_t>() : NULL);
}
/**
* Does the request need to check for cached copies of the same block
* in the memory hierarchy above.
**/
bool
mustCheckAbove() const
{
return cmd == MemCmd::HardPFReq || isEviction();
}
/**
* Is this packet a clean eviction, including both actual clean
* evict packets, but also clean writebacks.
*/
bool
isCleanEviction() const
{
return cmd == MemCmd::CleanEvict || cmd == MemCmd::WritebackClean;
}
bool
isMaskedWrite() const
{
return (cmd == MemCmd::WriteReq && !req->getByteEnable().empty());
}
/**
* Check a functional request against a memory value represented
* by a base/size pair and an associated data array. If the
* current packet is a read, it may be satisfied by the memory
* value. If the current packet is a write, it may update the
* memory value.
*/
bool
trySatisfyFunctional(Printable *obj, Addr base, bool is_secure, int size,
uint8_t *_data);
/**
* Push label for PrintReq (safe to call unconditionally).
*/
void
pushLabel(const std::string &lbl)
{
if (isPrint())
safe_cast<PrintReqState*>(senderState)->pushLabel(lbl);
}
/**
* Pop label for PrintReq (safe to call unconditionally).
*/
void
popLabel()
{
if (isPrint())
safe_cast<PrintReqState*>(senderState)->popLabel();
}
void print(std::ostream &o, int verbosity = 0,
const std::string &prefix = "") const;
/**
* A no-args wrapper of print(std::ostream...)
* meant to be invoked from DPRINTFs
* avoiding string overheads in fast mode
* @return string with the request's type and start<->end addresses
*/
std::string print() const;
};
#endif //__MEM_PACKET_HH
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