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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.
*/
/**
* @file
* Declaration of the Packet class.
*/
#ifndef __MEM_PACKET_HH__
#define __MEM_PACKET_HH__
#include <bitset>
#include <cassert>
#include <initializer_list>
#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 "mem/htm.hh"
#include "mem/request.hh"
#include "sim/byteswap.hh"
namespace gem5
{
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,
WriteCompleteResp,
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 and MessageResp are deprecated.
MemFenceReq = SwapResp + 3,
MemSyncReq, // memory synchronization request (e.g., cache invalidate)
MemSyncResp, // memory synchronization response
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,
// hardware transactional memory
HTMReq,
HTMReqResp,
HTMAbort,
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
};
static constexpr unsigned long long
buildAttributes(std::initializer_list<Attribute> attrs)
{
unsigned long long ret = 0;
for (const auto &attr: attrs)
ret |= (1ULL << attr);
return ret;
}
/**
* 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;
CommandInfo(std::initializer_list<Attribute> attrs,
Command _response, const std::string &_str) :
attributes(buildAttributes(attrs)), response(_response), str(_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 requestor 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 gem5::Flags<FlagsType> Flags;
private:
enum : FlagsType
{
// Flags to transfer across when copying a packet
COPY_FLAGS = 0x000000FF,
// 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,
// hardware transactional memory
// Indicates that this packet/request has returned from the
// cache hierarchy in a failed transaction. The core is
// notified like this.
FAILS_TRANSACTION = 0x00000040,
// Indicates that this packet/request originates in the CPU executing
// in transactional mode, i.e. in a transaction.
FROM_TRANSACTION = 0x00000080,
/// 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;
// hardware transactional memory
/**
* Holds the return status of the transaction.
* The default case will be NO_FAIL, otherwise this will specify the
* reason for the transaction's failure in the memory subsystem.
*/
HtmCacheFailure htmReturnReason;
/**
* A global unique identifier of the transaction.
* This is used for correctness/debugging only.
*/
uint64_t htmTransactionUid;
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 RequestorID requestorId() const { return req->requestorId(); }
// 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),
htmReturnReason(HtmCacheFailure::NO_FAIL),
htmTransactionUid(0),
headerDelay(0), snoopDelay(0),
payloadDelay(0), senderState(NULL)
{
flags.clear();
if (req->hasPaddr()) {
addr = req->getPaddr();
flags.set(VALID_ADDR);
_isSecure = req->isSecure();
}
/**
* hardware transactional memory
*
* This is a bit of a hack!
* Technically the address of a HTM command is set to zero
* but is not valid. The reason that we pretend it's valid is
* to void the getAddr() function from failing. It would be
* cumbersome to add control flow in many places to check if the
* packet represents a HTM command before calling getAddr().
*/
if (req->isHTMCmd()) {
flags.set(VALID_ADDR);
assert(addr == 0x0);
}
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),
htmReturnReason(HtmCacheFailure::NO_FAIL),
htmTransactionUid(0),
headerDelay(0),
snoopDelay(0), payloadDelay(0), senderState(NULL)
{
flags.clear();
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()),
htmReturnReason(HtmCacheFailure::NO_FAIL),
htmTransactionUid(0),
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));
if (pkt->isHtmTransactional())
setHtmTransactional(pkt->getHtmTransactionUid());
if (pkt->htmTransactionFailedInCache()) {
setHtmTransactionFailedInCache(
pkt->getHtmTransactionFailedInCacheRC()
);
}
// 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->isHTMCmd()) {
if (req->isHTMAbort())
return MemCmd::HTMAbort;
else
return MemCmd::HTMReq;
} else 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;
/** 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);
/**
* 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->isMasked());
}
/**
* 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;
// hardware transactional memory
/**
* Communicates to the core that a packet was processed by the memory
* subsystem while running in transactional mode.
* It may happen that the transaction has failed at the memory subsystem
* and this needs to be communicated to the core somehow.
* This function decorates the response packet with flags to indicate
* such a situation has occurred.
*/
void makeHtmTransactionalReqResponse(const HtmCacheFailure ret_code);
/**
* Stipulates that this packet/request originates in the CPU executing
* in transactional mode, i.e. within a transaction.
*/
void setHtmTransactional(uint64_t val);
/**
* Returns whether or not this packet/request originates in the CPU
* executing in transactional mode, i.e. within a transaction.
*/
bool isHtmTransactional() const;
/**
* If a packet/request originates in a CPU executing in transactional
* mode, i.e. within a transaction, this function returns the unique ID
* of the transaction. This is used for verifying correctness
* and debugging.
*/
uint64_t getHtmTransactionUid() const;
/**
* Stipulates that this packet/request has returned from the
* cache hierarchy in a failed transaction. The core is
* notified like this.
*/
void setHtmTransactionFailedInCache(const HtmCacheFailure ret_code);
/**
* Returns whether or not this packet/request has returned from the
* cache hierarchy in a failed transaction. The core is
* notified liked this.
*/
bool htmTransactionFailedInCache() const;
/**
* If a packet/request has returned from the cache hierarchy in a
* failed transaction, this function returns the failure reason.
*/
HtmCacheFailure getHtmTransactionFailedInCacheRC() const;
};
} // namespace gem5
#endif //__MEM_PACKET_HH