src/mem/request.hh - arm/gem5 - Git at Google

 /*
  * Copyright (c) 2012-2013 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) 2002-2005 The Regents of The University of Michigan
  * 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
  */

 /**
  * @file
  * Declaration of a request, the overall memory request consisting of
  the parts of the request that are persistent throughout the transaction.
  */

 #ifndef __MEM_REQUEST_HH__
 #define __MEM_REQUEST_HH__

 #include <cassert>
 #include <climits>

 #include "base/flags.hh"
 #include "base/misc.hh"
 #include "base/types.hh"
 #include "sim/core.hh"

 /**
  * Special TaskIds that are used for per-context-switch stats dumps
  * and Cache Occupancy. Having too many tasks seems to be a problem
  * with vector stats. 1024 seems to be a reasonable number that
  * doesn't cause a problem with stats and is large enough to realistic
  * benchmarks (Linux/Android boot, BBench, etc.)
  */

 namespace ContextSwitchTaskId {
     enum TaskId {
         MaxNormalTaskId = 1021, /* Maximum number of normal tasks */
         Prefetcher = 1022, /* For cache lines brought in by prefetcher */
         DMA = 1023, /* Mostly Table Walker */
         Unknown = 1024,
         NumTaskId
     };
 }

 class Request;

 typedef Request* RequestPtr;
 typedef uint16_t MasterID;

 class Request
 {
   public:
     typedef uint32_t FlagsType;
     typedef uint8_t ArchFlagsType;
     typedef ::Flags<FlagsType> Flags;

     /**
      * Architecture specific flags.
      *
      * These bits int the flag field are reserved for
      * architecture-specific code. For example, SPARC uses them to
      * represent ASIs.
      */
     static const FlagsType ARCH_BITS                   = 0x000000FF;
     /** The request was an instruction fetch. */
     static const FlagsType INST_FETCH                  = 0x00000100;
     /** The virtual address is also the physical address. */
     static const FlagsType PHYSICAL                    = 0x00000200;
     /** The request is an ALPHA VPTE pal access (hw_ld). */
     static const FlagsType VPTE                        = 0x00000400;
     /** Use the alternate mode bits in ALPHA. */
     static const FlagsType ALTMODE                     = 0x00000800;
     /** The request is to an uncacheable address. */
     static const FlagsType UNCACHEABLE                 = 0x00001000;
     /** This request is to a memory mapped register. */
     static const FlagsType MMAPPED_IPR                  = 0x00002000;
     /** This request is a clear exclusive. */
     static const FlagsType CLEAR_LL                    = 0x00004000;
     /** This request is made in privileged mode. */
     static const FlagsType PRIVILEGED                   = 0x00008000;

     /** This is a write that is targeted and zeroing an entire cache block.
      * There is no need for a read/modify/write
      */
     static const FlagsType CACHE_BLOCK_ZERO            = 0x00010000;

     /** The request should not cause a memory access. */
     static const FlagsType NO_ACCESS                   = 0x00080000;
     /** This request will lock or unlock the accessed memory. When used with
      * a load, the access locks the particular chunk of memory. When used
      * with a store, it unlocks. The rule is that locked accesses have to be
      * made up of a locked load, some operation on the data, and then a locked
      * store.
      */
     static const FlagsType LOCKED                      = 0x00100000;
     /** The request is a Load locked/store conditional. */
     static const FlagsType LLSC                        = 0x00200000;
     /** This request is for a memory swap. */
     static const FlagsType MEM_SWAP                    = 0x00400000;
     static const FlagsType MEM_SWAP_COND               = 0x00800000;

     /** The request is a prefetch. */
     static const FlagsType PREFETCH                    = 0x01000000;
     /** The request should be prefetched into the exclusive state. */
     static const FlagsType PF_EXCLUSIVE                = 0x02000000;
     /** The request should be marked as LRU. */
     static const FlagsType EVICT_NEXT                  = 0x04000000;

     /** The request should be handled by the generic IPR code (only
      * valid together with MMAPPED_IPR) */
     static const FlagsType GENERIC_IPR                 = 0x08000000;

     /** The request targets the secure memory space. */
     static const FlagsType SECURE                      = 0x10000000;
     /** The request is a page table walk */
     static const FlagsType PT_WALK                     = 0x20000000;

     /** These flags are *not* cleared when a Request object is reused
        (assigned a new address). */
     static const FlagsType STICKY_FLAGS = INST_FETCH;

     /** Request Ids that are statically allocated
      * @{*/
     /** This request id is used for writeback requests by the caches */
     static const MasterID wbMasterId = 0;
     /** This request id is used for functional requests that don't come from a
      * particular device
      */
     static const MasterID funcMasterId = 1;
     /** This request id is used for message signaled interrupts */
     static const MasterID intMasterId = 2;
     /** Invalid request id for assertion checking only. It is invalid behavior
      * to ever send this id as part of a request.
      * @todo C++1x replace with numeric_limits when constexpr is added  */
     static const MasterID invldMasterId = USHRT_MAX;
     /** @} */

     /** Invalid or unknown Pid. Possible when operating system is not present
      *  or has not assigned a pid yet */
     static const uint32_t invldPid = UINT_MAX;

   private:
     typedef uint8_t PrivateFlagsType;
     typedef ::Flags<PrivateFlagsType> PrivateFlags;

     /** Whether or not the size is valid. */
     static const PrivateFlagsType VALID_SIZE           = 0x00000001;
     /** Whether or not paddr is valid (has been written yet). */
     static const PrivateFlagsType VALID_PADDR          = 0x00000002;
     /** Whether or not the vaddr & asid are valid. */
     static const PrivateFlagsType VALID_VADDR          = 0x00000004;
     /** Whether or not the pc is valid. */
     static const PrivateFlagsType VALID_PC             = 0x00000010;
     /** Whether or not the context ID is valid. */
     static const PrivateFlagsType VALID_CONTEXT_ID     = 0x00000020;
     static const PrivateFlagsType VALID_THREAD_ID      = 0x00000040;
     /** Whether or not the sc result is valid. */
     static const PrivateFlagsType VALID_EXTRA_DATA     = 0x00000080;

     /** These flags are *not* cleared when a Request object is reused
        (assigned a new address). */
     static const PrivateFlagsType STICKY_PRIVATE_FLAGS =
         VALID_CONTEXT_ID | VALID_THREAD_ID;

   private:
     /**
      * The physical address of the request. Valid only if validPaddr
      * is set.
      */
     Addr _paddr;

     /**
      * The size of the request. This field must be set when vaddr or
      * paddr is written via setVirt() or setPhys(), so it is always
      * valid as long as one of the address fields is valid.
      */
     int _size;

     /** The requestor ID which is unique in the system for all ports
      * that are capable of issuing a transaction
      */
     MasterID _masterId;

     /** Flag structure for the request. */
     Flags _flags;

     /** Private flags for field validity checking. */
     PrivateFlags privateFlags;

     /**
      * The time this request was started. Used to calculate
      * latencies. This field is set to curTick() any time paddr or vaddr
      * is written.
      */
     Tick _time;

     /**
      * The task id associated with this request
      */
     uint32_t _taskId;

     /** The address space ID. */
     int _asid;

     /** The virtual address of the request. */
     Addr _vaddr;

     /**
      * Extra data for the request, such as the return value of
      * store conditional or the compare value for a CAS. */
     uint64_t _extraData;

     /** The context ID (for statistics, typically). */
     int _contextId;
     /** The thread ID (id within this CPU) */
     int _threadId;

     /** program counter of initiating access; for tracing/debugging */
     Addr _pc;

   public:
     /** Minimal constructor.  No fields are initialized.
      *  (Note that _flags and privateFlags are cleared by Flags
      *  default constructor.)
      */
     Request()
         : _taskId(ContextSwitchTaskId::Unknown),
         translateDelta(0), accessDelta(0), depth(0)
     {}

     /**
      * Constructor for physical (e.g. device) requests.  Initializes
      * just physical address, size, flags, and timestamp (to curTick()).
      * These fields are adequate to perform a request.
      */
     Request(Addr paddr, int size, Flags flags, MasterID mid)
         : _taskId(ContextSwitchTaskId::Unknown)
     {
         setPhys(paddr, size, flags, mid);
     }

     Request(Addr paddr, int size, Flags flags, MasterID mid, Tick time)
         : _taskId(ContextSwitchTaskId::Unknown)
     {
         setPhys(paddr, size, flags, mid, time);
     }

     Request(Addr paddr, int size, Flags flags, MasterID mid, Tick time, Addr pc)
         : _taskId(ContextSwitchTaskId::Unknown)
     {
         setPhys(paddr, size, flags, mid, time);
         privateFlags.set(VALID_PC);
         _pc = pc;
     }

     Request(int asid, Addr vaddr, int size, Flags flags, MasterID mid, Addr pc,
             int cid, ThreadID tid)
         : _taskId(ContextSwitchTaskId::Unknown)
     {
         setVirt(asid, vaddr, size, flags, mid, pc);
         setThreadContext(cid, tid);
     }

     ~Request() {}

     /**
      * Set up CPU and thread numbers.
      */
     void
     setThreadContext(int context_id, ThreadID tid)
     {
         _contextId = context_id;
         _threadId = tid;
         privateFlags.set(VALID_CONTEXT_ID|VALID_THREAD_ID);
     }

     /**
      * Set up a physical (e.g. device) request in a previously
      * allocated Request object.
      */
     void
     setPhys(Addr paddr, int size, Flags flags, MasterID mid, Tick time)
     {
         assert(size >= 0);
         _paddr = paddr;
         _size = size;
         _time = time;
         _masterId = mid;
         _flags.clear(~STICKY_FLAGS);
         _flags.set(flags);
         privateFlags.clear(~STICKY_PRIVATE_FLAGS);
         privateFlags.set(VALID_PADDR|VALID_SIZE);
         depth = 0;
         accessDelta = 0;
         //translateDelta = 0;
     }

     void
     setPhys(Addr paddr, int size, Flags flags, MasterID mid)
     {
         setPhys(paddr, size, flags, mid, curTick());
     }

     /**
      * Set up a virtual (e.g., CPU) request in a previously
      * allocated Request object.
      */
     void
     setVirt(int asid, Addr vaddr, int size, Flags flags, MasterID mid, Addr pc)
     {
         assert(size >= 0);
         _asid = asid;
         _vaddr = vaddr;
         _size = size;
         _masterId = mid;
         _pc = pc;
         _time = curTick();

         _flags.clear(~STICKY_FLAGS);
         _flags.set(flags);
         privateFlags.clear(~STICKY_PRIVATE_FLAGS);
         privateFlags.set(VALID_VADDR|VALID_SIZE|VALID_PC);
         depth = 0;
         accessDelta = 0;
         translateDelta = 0;
     }

     /**
      * Set just the physical address.  This usually used to record the
      * result of a translation. However, when using virtualized CPUs
      * setPhys() is sometimes called to finalize a physical address
      * without a virtual address, so we can't check if the virtual
      * address is valid.
      */
     void
     setPaddr(Addr paddr)
     {
         _paddr = paddr;
         privateFlags.set(VALID_PADDR);
     }

     /**
      * Generate two requests as if this request had been split into two
      * pieces. The original request can't have been translated already.
      */
     void splitOnVaddr(Addr split_addr, RequestPtr &req1, RequestPtr &req2)
     {
         assert(privateFlags.isSet(VALID_VADDR));
         assert(privateFlags.noneSet(VALID_PADDR));
         assert(split_addr > _vaddr && split_addr < _vaddr + _size);
         req1 = new Request;
         *req1 = *this;
         req2 = new Request;
         *req2 = *this;
         req1->_size = split_addr - _vaddr;
         req2->_vaddr = split_addr;
         req2->_size = _size - req1->_size;
     }

     /**
      * Accessor for paddr.
      */
     bool
     hasPaddr()
     {
         return privateFlags.isSet(VALID_PADDR);
     }

     Addr
     getPaddr()
     {
         assert(privateFlags.isSet(VALID_PADDR));
         return _paddr;
     }

     /**
      * Time for the TLB/table walker to successfully translate this request.
      */
     Tick translateDelta;

     /**
      * Access latency to complete this memory transaction not including
      * translation time.
      */
     Tick accessDelta;

     /**
      * Level of the cache hierachy where this request was responded to
      * (e.g. 0 = L1; 1 = L2).
      */
     int depth;

     /**
      *  Accessor for size.
      */
     bool
     hasSize()
     {
         return privateFlags.isSet(VALID_SIZE);
     }

     int
     getSize()
     {
         assert(privateFlags.isSet(VALID_SIZE));
         return _size;
     }

     /** Accessor for time. */
     Tick
     time() const
     {
         assert(privateFlags.isSet(VALID_PADDR|VALID_VADDR));
         return _time;
     }

     void
     time(Tick time)
     {
         assert(privateFlags.isSet(VALID_PADDR|VALID_VADDR));
         _time = time;
     }

     /** Accessor for flags. */
     Flags
     getFlags()
     {
         assert(privateFlags.isSet(VALID_PADDR|VALID_VADDR));
         return _flags;
     }

     /** Note that unlike other accessors, this function sets *specific
        flags* (ORs them in); it does not assign its argument to the
        _flags field.  Thus this method should rightly be called
        setFlags() and not just flags(). */
     void
     setFlags(Flags flags)
     {
         assert(privateFlags.isSet(VALID_PADDR|VALID_VADDR));
         _flags.set(flags);
     }

     void
     setArchFlags(Flags flags)
     {
         assert(privateFlags.isSet(VALID_PADDR|VALID_VADDR));
         _flags.set(flags & ARCH_BITS);
     }

     /** Accessor function for vaddr.*/
     Addr
     getVaddr()
     {
         assert(privateFlags.isSet(VALID_VADDR));
         return _vaddr;
     }

     /** Accesssor for the requestor id. */
     MasterID
     masterId()
     {
         return _masterId;
     }

     uint32_t
     taskId() const
     {
         return _taskId;
     }

     void
     taskId(uint32_t id) {
         _taskId = id;
     }

     /** Accessor function for asid.*/
     int
     getAsid()
     {
         assert(privateFlags.isSet(VALID_VADDR));
         return _asid;
     }

     /** Accessor function for asid.*/
     void
     setAsid(int asid)
     {
         _asid = asid;
     }

     /** Accessor function for architecture-specific flags.*/
     ArchFlagsType
     getArchFlags()
     {
         assert(privateFlags.isSet(VALID_PADDR|VALID_VADDR));
         return _flags & ARCH_BITS;
     }

     /** Accessor function to check if sc result is valid. */
     bool
     extraDataValid()
     {
         return privateFlags.isSet(VALID_EXTRA_DATA);
     }

     /** Accessor function for store conditional return value.*/
     uint64_t
     getExtraData() const
     {
         assert(privateFlags.isSet(VALID_EXTRA_DATA));
         return _extraData;
     }

     /** Accessor function for store conditional return value.*/
     void
     setExtraData(uint64_t extraData)
     {
         _extraData = extraData;
         privateFlags.set(VALID_EXTRA_DATA);
     }

     bool
     hasContextId() const
     {
         return privateFlags.isSet(VALID_CONTEXT_ID);
     }

     /** Accessor function for context ID.*/
     int
     contextId() const
     {
         assert(privateFlags.isSet(VALID_CONTEXT_ID));
         return _contextId;
     }

     /** Accessor function for thread ID. */
     int
     threadId() const
     {
         assert(privateFlags.isSet(VALID_THREAD_ID));
         return _threadId;
     }

     void
     setPC(Addr pc)
     {
         privateFlags.set(VALID_PC);
         _pc = pc;
     }

     bool
     hasPC() const
     {
         return privateFlags.isSet(VALID_PC);
     }

     /** Accessor function for pc.*/
     Addr
     getPC() const
     {
         assert(privateFlags.isSet(VALID_PC));
         return _pc;
     }

     /**
      * Increment/Get the depth at which this request is responded to.
      * This currently happens when the request misses in any cache level.
      */
     void incAccessDepth() { depth++; }
     int getAccessDepth() const { return depth; }

     /**
      * Set/Get the time taken for this request to be successfully translated.
      */
     void setTranslateLatency() { translateDelta = curTick() - _time; }
     Tick getTranslateLatency() const { return translateDelta; }

     /**
      * Set/Get the time taken to complete this request's access, not including
      *  the time to successfully translate the request.
      */
     void setAccessLatency() { accessDelta = curTick() - _time - translateDelta; }
     Tick getAccessLatency() const { return accessDelta; }

     /** Accessor functions for flags.  Note that these are for testing
        only; setting flags should be done via setFlags(). */
     bool isUncacheable() const { return _flags.isSet(UNCACHEABLE); }
     bool isInstFetch() const { return _flags.isSet(INST_FETCH); }
     bool isPrefetch() const { return _flags.isSet(PREFETCH); }
     bool isLLSC() const { return _flags.isSet(LLSC); }
     bool isPriv() const { return _flags.isSet(PRIVILEGED); }
     bool isLocked() const { return _flags.isSet(LOCKED); }
     bool isSwap() const { return _flags.isSet(MEM_SWAP|MEM_SWAP_COND); }
     bool isCondSwap() const { return _flags.isSet(MEM_SWAP_COND); }
     bool isMmappedIpr() const { return _flags.isSet(MMAPPED_IPR); }
     bool isClearLL() const { return _flags.isSet(CLEAR_LL); }
     bool isSecure() const { return _flags.isSet(SECURE); }
     bool isPTWalk() const { return _flags.isSet(PT_WALK); }
 };

 #endif // __MEM_REQUEST_HH__
	/*
	* Copyright (c) 2012-2013 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) 2002-2005 The Regents of The University of Michigan
	* 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
	*/

	/**
	* @file
	* Declaration of a request, the overall memory request consisting of
	the parts of the request that are persistent throughout the transaction.
	*/

	#ifndef __MEM_REQUEST_HH__
	#define __MEM_REQUEST_HH__

	#include <cassert>
	#include <climits>

	#include "base/flags.hh"
	#include "base/misc.hh"
	#include "base/types.hh"
	#include "sim/core.hh"

	/**
	* Special TaskIds that are used for per-context-switch stats dumps
	* and Cache Occupancy. Having too many tasks seems to be a problem
	* with vector stats. 1024 seems to be a reasonable number that
	* doesn't cause a problem with stats and is large enough to realistic
	* benchmarks (Linux/Android boot, BBench, etc.)
	*/

	namespace ContextSwitchTaskId {
	enum TaskId {
	MaxNormalTaskId = 1021, /* Maximum number of normal tasks */
	Prefetcher = 1022, /* For cache lines brought in by prefetcher */
	DMA = 1023, /* Mostly Table Walker */
	Unknown = 1024,
	NumTaskId
	};
	}

	class Request;

	typedef Request* RequestPtr;
	typedef uint16_t MasterID;

	class Request
	{
	public:
	typedef uint32_t FlagsType;
	typedef uint8_t ArchFlagsType;
	typedef ::Flags<FlagsType> Flags;

	/**
	* Architecture specific flags.
	*
	* These bits int the flag field are reserved for
	* architecture-specific code. For example, SPARC uses them to
	* represent ASIs.
	*/
	static const FlagsType ARCH_BITS = 0x000000FF;
	/** The request was an instruction fetch. */
	static const FlagsType INST_FETCH = 0x00000100;
	/** The virtual address is also the physical address. */
	static const FlagsType PHYSICAL = 0x00000200;
	/** The request is an ALPHA VPTE pal access (hw_ld). */
	static const FlagsType VPTE = 0x00000400;
	/** Use the alternate mode bits in ALPHA. */
	static const FlagsType ALTMODE = 0x00000800;
	/** The request is to an uncacheable address. */
	static const FlagsType UNCACHEABLE = 0x00001000;
	/** This request is to a memory mapped register. */
	static const FlagsType MMAPPED_IPR = 0x00002000;
	/** This request is a clear exclusive. */
	static const FlagsType CLEAR_LL = 0x00004000;
	/** This request is made in privileged mode. */
	static const FlagsType PRIVILEGED = 0x00008000;

	/** This is a write that is targeted and zeroing an entire cache block.
	* There is no need for a read/modify/write
	*/
	static const FlagsType CACHE_BLOCK_ZERO = 0x00010000;

	/** The request should not cause a memory access. */
	static const FlagsType NO_ACCESS = 0x00080000;
	/** This request will lock or unlock the accessed memory. When used with
	* a load, the access locks the particular chunk of memory. When used
	* with a store, it unlocks. The rule is that locked accesses have to be
	* made up of a locked load, some operation on the data, and then a locked
	* store.
	*/
	static const FlagsType LOCKED = 0x00100000;
	/** The request is a Load locked/store conditional. */
	static const FlagsType LLSC = 0x00200000;
	/** This request is for a memory swap. */
	static const FlagsType MEM_SWAP = 0x00400000;
	static const FlagsType MEM_SWAP_COND = 0x00800000;

	/** The request is a prefetch. */
	static const FlagsType PREFETCH = 0x01000000;
	/** The request should be prefetched into the exclusive state. */
	static const FlagsType PF_EXCLUSIVE = 0x02000000;
	/** The request should be marked as LRU. */
	static const FlagsType EVICT_NEXT = 0x04000000;

	/** The request should be handled by the generic IPR code (only
	* valid together with MMAPPED_IPR) */
	static const FlagsType GENERIC_IPR = 0x08000000;

	/** The request targets the secure memory space. */
	static const FlagsType SECURE = 0x10000000;
	/** The request is a page table walk */
	static const FlagsType PT_WALK = 0x20000000;

	/** These flags are not cleared when a Request object is reused
	(assigned a new address). */
	static const FlagsType STICKY_FLAGS = INST_FETCH;

	/** Request Ids that are statically allocated
	* @{*/
	/** This request id is used for writeback requests by the caches */
	static const MasterID wbMasterId = 0;
	/** This request id is used for functional requests that don't come from a
	* particular device
	*/
	static const MasterID funcMasterId = 1;
	/** This request id is used for message signaled interrupts */
	static const MasterID intMasterId = 2;
	/** Invalid request id for assertion checking only. It is invalid behavior
	* to ever send this id as part of a request.
	* @todo C++1x replace with numeric_limits when constexpr is added */
	static const MasterID invldMasterId = USHRT_MAX;
	/** @} */

	/** Invalid or unknown Pid. Possible when operating system is not present
	* or has not assigned a pid yet */
	static const uint32_t invldPid = UINT_MAX;

	private:
	typedef uint8_t PrivateFlagsType;
	typedef ::Flags<PrivateFlagsType> PrivateFlags;

	/** Whether or not the size is valid. */
	static const PrivateFlagsType VALID_SIZE = 0x00000001;
	/** Whether or not paddr is valid (has been written yet). */
	static const PrivateFlagsType VALID_PADDR = 0x00000002;
	/** Whether or not the vaddr & asid are valid. */
	static const PrivateFlagsType VALID_VADDR = 0x00000004;
	/** Whether or not the pc is valid. */
	static const PrivateFlagsType VALID_PC = 0x00000010;
	/** Whether or not the context ID is valid. */
	static const PrivateFlagsType VALID_CONTEXT_ID = 0x00000020;
	static const PrivateFlagsType VALID_THREAD_ID = 0x00000040;
	/** Whether or not the sc result is valid. */
	static const PrivateFlagsType VALID_EXTRA_DATA = 0x00000080;

	/** These flags are not cleared when a Request object is reused
	(assigned a new address). */
	static const PrivateFlagsType STICKY_PRIVATE_FLAGS =
	VALID_CONTEXT_ID \| VALID_THREAD_ID;

	private:
	/**
	* The physical address of the request. Valid only if validPaddr
	* is set.
	*/
	Addr _paddr;

	/**
	* The size of the request. This field must be set when vaddr or
	* paddr is written via setVirt() or setPhys(), so it is always
	* valid as long as one of the address fields is valid.
	*/
	int _size;

	/** The requestor ID which is unique in the system for all ports
	* that are capable of issuing a transaction
	*/
	MasterID _masterId;

	/** Flag structure for the request. */
	Flags _flags;

	/** Private flags for field validity checking. */
	PrivateFlags privateFlags;

	/**
	* The time this request was started. Used to calculate
	* latencies. This field is set to curTick() any time paddr or vaddr
	* is written.
	*/
	Tick _time;

	/**
	* The task id associated with this request
	*/
	uint32_t _taskId;

	/** The address space ID. */
	int _asid;

	/** The virtual address of the request. */
	Addr _vaddr;

	/**
	* Extra data for the request, such as the return value of
	* store conditional or the compare value for a CAS. */
	uint64_t _extraData;

	/** The context ID (for statistics, typically). */
	int _contextId;
	/** The thread ID (id within this CPU) */
	int _threadId;

	/** program counter of initiating access; for tracing/debugging */
	Addr _pc;

	public:
	/** Minimal constructor. No fields are initialized.
	* (Note that _flags and privateFlags are cleared by Flags
	* default constructor.)
	*/
	Request()
	: _taskId(ContextSwitchTaskId::Unknown),
	translateDelta(0), accessDelta(0), depth(0)
	{}

	/**
	* Constructor for physical (e.g. device) requests. Initializes
	* just physical address, size, flags, and timestamp (to curTick()).
	* These fields are adequate to perform a request.
	*/
	Request(Addr paddr, int size, Flags flags, MasterID mid)
	: _taskId(ContextSwitchTaskId::Unknown)
	{
	setPhys(paddr, size, flags, mid);
	}

	Request(Addr paddr, int size, Flags flags, MasterID mid, Tick time)
	: _taskId(ContextSwitchTaskId::Unknown)
	{
	setPhys(paddr, size, flags, mid, time);
	}

	Request(Addr paddr, int size, Flags flags, MasterID mid, Tick time, Addr pc)
	: _taskId(ContextSwitchTaskId::Unknown)
	{
	setPhys(paddr, size, flags, mid, time);
	privateFlags.set(VALID_PC);
	_pc = pc;
	}

	Request(int asid, Addr vaddr, int size, Flags flags, MasterID mid, Addr pc,
	int cid, ThreadID tid)
	: _taskId(ContextSwitchTaskId::Unknown)
	{
	setVirt(asid, vaddr, size, flags, mid, pc);
	setThreadContext(cid, tid);
	}

	~Request() {}

	/**
	* Set up CPU and thread numbers.
	*/
	void
	setThreadContext(int context_id, ThreadID tid)
	{
	_contextId = context_id;
	_threadId = tid;
	privateFlags.set(VALID_CONTEXT_ID\|VALID_THREAD_ID);
	}

	/**
	* Set up a physical (e.g. device) request in a previously
	* allocated Request object.
	*/
	void
	setPhys(Addr paddr, int size, Flags flags, MasterID mid, Tick time)
	{
	assert(size >= 0);
	_paddr = paddr;
	_size = size;
	_time = time;
	_masterId = mid;
	_flags.clear(~STICKY_FLAGS);
	_flags.set(flags);
	privateFlags.clear(~STICKY_PRIVATE_FLAGS);
	privateFlags.set(VALID_PADDR\|VALID_SIZE);
	depth = 0;
	accessDelta = 0;
	//translateDelta = 0;
	}

	void
	setPhys(Addr paddr, int size, Flags flags, MasterID mid)
	{
	setPhys(paddr, size, flags, mid, curTick());
	}

	/**
	* Set up a virtual (e.g., CPU) request in a previously
	* allocated Request object.
	*/
	void
	setVirt(int asid, Addr vaddr, int size, Flags flags, MasterID mid, Addr pc)
	{
	assert(size >= 0);
	_asid = asid;
	_vaddr = vaddr;
	_size = size;
	_masterId = mid;
	_pc = pc;
	_time = curTick();

	_flags.clear(~STICKY_FLAGS);
	_flags.set(flags);
	privateFlags.clear(~STICKY_PRIVATE_FLAGS);
	privateFlags.set(VALID_VADDR\|VALID_SIZE\|VALID_PC);
	depth = 0;
	accessDelta = 0;
	translateDelta = 0;
	}

	/**
	* Set just the physical address. This usually used to record the
	* result of a translation. However, when using virtualized CPUs
	* setPhys() is sometimes called to finalize a physical address
	* without a virtual address, so we can't check if the virtual
	* address is valid.
	*/
	void
	setPaddr(Addr paddr)
	{
	_paddr = paddr;
	privateFlags.set(VALID_PADDR);
	}

	/**
	* Generate two requests as if this request had been split into two
	* pieces. The original request can't have been translated already.
	*/
	void splitOnVaddr(Addr split_addr, RequestPtr &req1, RequestPtr &req2)
	{
	assert(privateFlags.isSet(VALID_VADDR));
	assert(privateFlags.noneSet(VALID_PADDR));
	assert(split_addr > _vaddr && split_addr < _vaddr + _size);
	req1 = new Request;
	req1 = this;
	req2 = new Request;
	req2 = this;
	req1->_size = split_addr - _vaddr;
	req2->_vaddr = split_addr;
	req2->_size = _size - req1->_size;
	}

	/**
	* Accessor for paddr.
	*/
	bool
	hasPaddr()
	{
	return privateFlags.isSet(VALID_PADDR);
	}

	Addr
	getPaddr()
	{
	assert(privateFlags.isSet(VALID_PADDR));
	return _paddr;
	}

	/**
	* Time for the TLB/table walker to successfully translate this request.
	*/
	Tick translateDelta;

	/**
	* Access latency to complete this memory transaction not including
	* translation time.
	*/
	Tick accessDelta;

	/**
	* Level of the cache hierachy where this request was responded to
	* (e.g. 0 = L1; 1 = L2).
	*/
	int depth;

	/**
	* Accessor for size.
	*/
	bool
	hasSize()
	{
	return privateFlags.isSet(VALID_SIZE);
	}

	int
	getSize()
	{
	assert(privateFlags.isSet(VALID_SIZE));
	return _size;
	}

	/** Accessor for time. */
	Tick
	time() const
	{
	assert(privateFlags.isSet(VALID_PADDR\|VALID_VADDR));
	return _time;
	}

	void
	time(Tick time)
	{
	assert(privateFlags.isSet(VALID_PADDR\|VALID_VADDR));
	_time = time;
	}

	/** Accessor for flags. */
	Flags
	getFlags()
	{
	assert(privateFlags.isSet(VALID_PADDR\|VALID_VADDR));
	return _flags;
	}

	/** Note that unlike other accessors, this function sets *specific
	flags* (ORs them in); it does not assign its argument to the
	_flags field. Thus this method should rightly be called
	setFlags() and not just flags(). */
	void
	setFlags(Flags flags)
	{
	assert(privateFlags.isSet(VALID_PADDR\|VALID_VADDR));
	_flags.set(flags);
	}

	void
	setArchFlags(Flags flags)
	{
	assert(privateFlags.isSet(VALID_PADDR\|VALID_VADDR));
	_flags.set(flags & ARCH_BITS);
	}

	/** Accessor function for vaddr.*/
	Addr
	getVaddr()
	{
	assert(privateFlags.isSet(VALID_VADDR));
	return _vaddr;
	}

	/** Accesssor for the requestor id. */
	MasterID
	masterId()
	{
	return _masterId;
	}

	uint32_t
	taskId() const
	{
	return _taskId;
	}

	void
	taskId(uint32_t id) {
	_taskId = id;
	}

	/** Accessor function for asid.*/
	int
	getAsid()
	{
	assert(privateFlags.isSet(VALID_VADDR));
	return _asid;
	}

	/** Accessor function for asid.*/
	void
	setAsid(int asid)
	{
	_asid = asid;
	}

	/** Accessor function for architecture-specific flags.*/
	ArchFlagsType
	getArchFlags()
	{
	assert(privateFlags.isSet(VALID_PADDR\|VALID_VADDR));
	return _flags & ARCH_BITS;
	}

	/** Accessor function to check if sc result is valid. */
	bool
	extraDataValid()
	{
	return privateFlags.isSet(VALID_EXTRA_DATA);
	}

	/** Accessor function for store conditional return value.*/
	uint64_t
	getExtraData() const
	{
	assert(privateFlags.isSet(VALID_EXTRA_DATA));
	return _extraData;
	}

	/** Accessor function for store conditional return value.*/
	void
	setExtraData(uint64_t extraData)
	{
	_extraData = extraData;
	privateFlags.set(VALID_EXTRA_DATA);
	}

	bool
	hasContextId() const
	{
	return privateFlags.isSet(VALID_CONTEXT_ID);
	}

	/** Accessor function for context ID.*/
	int
	contextId() const
	{
	assert(privateFlags.isSet(VALID_CONTEXT_ID));
	return _contextId;
	}

	/** Accessor function for thread ID. */
	int
	threadId() const
	{
	assert(privateFlags.isSet(VALID_THREAD_ID));
	return _threadId;
	}

	void
	setPC(Addr pc)
	{
	privateFlags.set(VALID_PC);
	_pc = pc;
	}

	bool
	hasPC() const
	{
	return privateFlags.isSet(VALID_PC);
	}

	/** Accessor function for pc.*/
	Addr
	getPC() const
	{
	assert(privateFlags.isSet(VALID_PC));
	return _pc;
	}

	/**
	* Increment/Get the depth at which this request is responded to.
	* This currently happens when the request misses in any cache level.
	*/
	void incAccessDepth() { depth++; }
	int getAccessDepth() const { return depth; }

	/**
	* Set/Get the time taken for this request to be successfully translated.
	*/
	void setTranslateLatency() { translateDelta = curTick() - _time; }
	Tick getTranslateLatency() const { return translateDelta; }

	/**
	* Set/Get the time taken to complete this request's access, not including
	* the time to successfully translate the request.
	*/
	void setAccessLatency() { accessDelta = curTick() - _time - translateDelta; }
	Tick getAccessLatency() const { return accessDelta; }

	/** Accessor functions for flags. Note that these are for testing
	only; setting flags should be done via setFlags(). */
	bool isUncacheable() const { return _flags.isSet(UNCACHEABLE); }
	bool isInstFetch() const { return _flags.isSet(INST_FETCH); }
	bool isPrefetch() const { return _flags.isSet(PREFETCH); }
	bool isLLSC() const { return _flags.isSet(LLSC); }
	bool isPriv() const { return _flags.isSet(PRIVILEGED); }
	bool isLocked() const { return _flags.isSet(LOCKED); }
	bool isSwap() const { return _flags.isSet(MEM_SWAP\|MEM_SWAP_COND); }
	bool isCondSwap() const { return _flags.isSet(MEM_SWAP_COND); }
	bool isMmappedIpr() const { return _flags.isSet(MMAPPED_IPR); }
	bool isClearLL() const { return _flags.isSet(CLEAR_LL); }
	bool isSecure() const { return _flags.isSet(SECURE); }
	bool isPTWalk() const { return _flags.isSet(PT_WALK); }
	};

	#endif // __MEM_REQUEST_HH__