mem: Add const getters for write packet data

This patch takes a first step in tightening up how we use the data
pointer in write packets. A const getter is added for the pointer
itself (getConstPtr), and a number of member functions are also made
const accordingly. In a range of places throughout the memory system
the new member is used.

The patch also removes the unused isReadWrite function.

12 files changed, 36 insertions, 29 deletions

diff --git a/src/mem/abstract_mem.cc b/src/mem/abstract_mem.cc
index c819ce2fc..dca0403fb 100644
--- a/src/mem/abstract_mem.cc
+++ b/src/mem/abstract_mem.cc
@@ -309,7 +309,7 @@ AbstractMemory::checkLockedAddrList(PacketPtr pkt)
                     A, system()->getMasterName(pkt->req->masterId()),          \
                     pkt->getSize(), pkt->getAddr(),                            \
                     pkt->req->isUncacheable() ? 'U' : 'C');                    \
-            DDUMP(MemoryAccess, pkt->getPtr<uint8_t>(), pkt->getSize());       \
+            DDUMP(MemoryAccess, pkt->getConstPtr<uint8_t>(), pkt->getSize());  \
         }                                                                      \
     } while (0)
 
@@ -344,7 +344,8 @@ AbstractMemory::access(PacketPtr pkt)
         bool overwrite_mem = true;
         // keep a copy of our possible write value, and copy what is at the
         // memory address into the packet
-        std::memcpy(&overwrite_val[0], pkt->getPtr<uint8_t>(), pkt->getSize());
+        std::memcpy(&overwrite_val[0], pkt->getConstPtr<uint8_t>(),
+                    pkt->getSize());
         std::memcpy(pkt->getPtr<uint8_t>(), hostAddr, pkt->getSize());
 
         if (pkt->req->isCondSwap()) {
@@ -381,7 +382,7 @@ AbstractMemory::access(PacketPtr pkt)
     } else if (pkt->isWrite()) {
         if (writeOK(pkt)) {
             if (pmemAddr) {
-                memcpy(hostAddr, pkt->getPtr<uint8_t>(), pkt->getSize());
+                memcpy(hostAddr, pkt->getConstPtr<uint8_t>(), pkt->getSize());
                 DPRINTF(MemoryAccess, "%s wrote %x bytes to address %x\n",
                         __func__, pkt->getSize(), pkt->getAddr());
             }
@@ -416,7 +417,7 @@ AbstractMemory::functionalAccess(PacketPtr pkt)
         pkt->makeResponse();
     } else if (pkt->isWrite()) {
         if (pmemAddr)
-            memcpy(hostAddr, pkt->getPtr<uint8_t>(), pkt->getSize());
+            memcpy(hostAddr, pkt->getConstPtr<uint8_t>(), pkt->getSize());
         TRACE_PACKET("Write");
         pkt->makeResponse();
     } else if (pkt->isPrint()) {
diff --git a/src/mem/cache/cache.hh b/src/mem/cache/cache.hh
index b9a9a7823..e0bd29752 100644
--- a/src/mem/cache/cache.hh
+++ b/src/mem/cache/cache.hh
@@ -287,7 +287,7 @@ class Cache : public BaseCache
                                bool pending_downgrade = false);
     bool satisfyMSHR(MSHR *mshr, PacketPtr pkt, BlkType *blk);
 
-    void doTimingSupplyResponse(PacketPtr req_pkt, uint8_t *blk_data,
+    void doTimingSupplyResponse(PacketPtr req_pkt, const uint8_t *blk_data,
                                 bool already_copied, bool pending_inval);
 
     /**
diff --git a/src/mem/cache/cache_impl.hh b/src/mem/cache/cache_impl.hh
index 66abf6eff..f4099c0ef 100644
--- a/src/mem/cache/cache_impl.hh
+++ b/src/mem/cache/cache_impl.hh
@@ -357,7 +357,7 @@ Cache<TagStore>::access(PacketPtr pkt, BlkType *&blk,
             blk->status &= ~BlkWritable;
             ++fastWrites;
         }
-        std::memcpy(blk->data, pkt->getPtr<uint8_t>(), blkSize);
+        std::memcpy(blk->data, pkt->getConstPtr<uint8_t>(), blkSize);
         DPRINTF(Cache, "%s new state is %s\n", __func__, blk->print());
         incHitCount(pkt);
         return true;
@@ -1211,7 +1211,7 @@ Cache<TagStore>::recvTimingResp(PacketPtr pkt)
                 completion_time = clockEdge(responseLatency) +
                     pkt->lastWordDelay;
                 if (pkt->isRead() && !is_error) {
-                    target->pkt->setData(pkt->getPtr<uint8_t>());
+                    target->pkt->setData(pkt->getConstPtr<uint8_t>());
                 }
             }
             target->pkt->makeTimingResponse();
@@ -1535,7 +1535,7 @@ Cache<TagStore>::handleFill(PacketPtr pkt, BlkType *blk,
 
     // if we got new data, copy it in
     if (pkt->isRead()) {
-        std::memcpy(blk->data, pkt->getPtr<uint8_t>(), blkSize);
+        std::memcpy(blk->data, pkt->getConstPtr<uint8_t>(), blkSize);
     }
 
     blk->whenReady = clockEdge() + responseLatency * clockPeriod() +
@@ -1554,7 +1554,7 @@ Cache<TagStore>::handleFill(PacketPtr pkt, BlkType *blk,
 template<class TagStore>
 void
 Cache<TagStore>::
-doTimingSupplyResponse(PacketPtr req_pkt, uint8_t *blk_data,
+doTimingSupplyResponse(PacketPtr req_pkt, const uint8_t *blk_data,
                        bool already_copied, bool pending_inval)
 {
     // sanity check
@@ -1810,7 +1810,7 @@ Cache<TagStore>::recvTimingSnoopReq(PacketPtr pkt)
                 // the packet's invalidate flag is set...
                 assert(pkt->isInvalidate());
             }
-            doTimingSupplyResponse(pkt, wb_pkt->getPtr<uint8_t>(),
+            doTimingSupplyResponse(pkt, wb_pkt->getConstPtr<uint8_t>(),
                                    false, false);
 
             if (pkt->isInvalidate()) {
@@ -2020,7 +2020,7 @@ Cache<TagStore>::getTimingPacket()
             pkt = new Packet(tgt_pkt);
             pkt->allocate();
             if (pkt->isWrite()) {
-                pkt->setData(tgt_pkt->getPtr<uint8_t>());
+                pkt->setData(tgt_pkt->getConstPtr<uint8_t>());
             }
         }
     }
diff --git a/src/mem/external_slave.cc b/src/mem/external_slave.cc
index c2ec8e2e4..67800b9a2 100644
--- a/src/mem/external_slave.cc
+++ b/src/mem/external_slave.cc
@@ -108,7 +108,7 @@ StubSlavePort::recvAtomic(PacketPtr packet)
 
         DPRINTF(ExternalPort, "StubSlavePort: recvAtomic a: 0x%x size: %d"
             " data: ...\n", packet->getAddr(), size);
-        DDUMP(ExternalPort, packet->getPtr<uint8_t>(), size);
+        DDUMP(ExternalPort, packet->getConstPtr<uint8_t>(), size);
     }
 
     return 0;
diff --git a/src/mem/packet.cc b/src/mem/packet.cc
index 8bbd7ff18..9dd67746b 100644
--- a/src/mem/packet.cc
+++ b/src/mem/packet.cc
@@ -303,11 +303,11 @@ Packet::checkFunctional(Printable *obj, Addr addr, bool is_secure, int size,
         }
     } else if (isWrite()) {
         if (offset >= 0) {
-            memcpy(data + offset, getPtr<uint8_t>(),
+            memcpy(data + offset, getConstPtr<uint8_t>(),
                    (min(func_end, val_end) - func_start) + 1);
         } else {
             // val_start > func_start
-            memcpy(data, getPtr<uint8_t>() - offset,
+            memcpy(data, getConstPtr<uint8_t>() - offset,
                    (min(func_end, val_end) - val_start) + 1);
         }
     } else {
diff --git a/src/mem/packet.hh b/src/mem/packet.hh
index 8d84a7ccb..fea9dbaae 100644
--- a/src/mem/packet.hh
+++ b/src/mem/packet.hh
@@ -186,7 +186,6 @@ class MemCmd
     bool needsResponse() const  { return testCmdAttrib(NeedsResponse); }
     bool isInvalidate() const   { return testCmdAttrib(IsInvalidate); }
     bool hasData() const        { return testCmdAttrib(HasData); }
-    bool isReadWrite() const    { return isRead() && isWrite(); }
     bool isLLSC() const         { return testCmdAttrib(IsLlsc); }
     bool isSWPrefetch() const   { return testCmdAttrib(IsSWPrefetch); }
     bool isHWPrefetch() const   { return testCmdAttrib(IsHWPrefetch); }
@@ -501,7 +500,6 @@ class Packet : public Printable
     bool needsResponse() const  { return cmd.needsResponse(); }
     bool isInvalidate() const   { return cmd.isInvalidate(); }
     bool hasData() const        { return cmd.hasData(); }
-    bool isReadWrite() const    { return cmd.isReadWrite(); }
     bool isLLSC() const         { return cmd.isLLSC(); }
     bool isError() const        { return cmd.isError(); }
     bool isPrint() const        { return cmd.isPrint(); }
@@ -852,11 +850,19 @@ class Packet : public Printable
         return (T*)data;
     }
 
+    template <typename T>
+    const T*
+    getConstPtr() const
+    {
+        assert(flags.isSet(STATIC_DATA|DYNAMIC_DATA));
+        return (const T*)data;
+    }
+
     /**
      * return the value of what is pointed to in the packet.
      */
     template <typename T>
-    T get();
+    T get() const;
 
     /**
      * set the value in the data pointer to v.
@@ -868,7 +874,7 @@ class Packet : public Printable
      * Copy data into the packet from the provided pointer.
      */
     void
-    setData(uint8_t *p)
+    setData(const uint8_t *p)
     {
         if (p != getPtr<uint8_t>())
             std::memcpy(getPtr<uint8_t>(), p, getSize());
@@ -879,7 +885,7 @@ class Packet : public Printable
      * which is aligned to the given block size.
      */
     void
-    setDataFromBlock(uint8_t *blk_data, int blkSize)
+    setDataFromBlock(const uint8_t *blk_data, int blkSize)
     {
         setData(blk_data + getOffset(blkSize));
     }
@@ -889,16 +895,16 @@ class Packet : public Printable
      * is aligned to the given block size.
      */
     void
-    writeData(uint8_t *p)
+    writeData(uint8_t *p) const
     {
-        std::memcpy(p, getPtr<uint8_t>(), getSize());
+        std::memcpy(p, getConstPtr<uint8_t>(), getSize());
     }
 
     /**
      * Copy data from the packet to the memory at the provided pointer.
      */
     void
-    writeDataToBlock(uint8_t *blk_data, int blkSize)
+    writeDataToBlock(uint8_t *blk_data, int blkSize) const
     {
         writeData(blk_data + getOffset(blkSize));
     }
diff --git a/src/mem/packet_access.hh b/src/mem/packet_access.hh
index fca9606fc..9e6f1cbb1 100644
--- a/src/mem/packet_access.hh
+++ b/src/mem/packet_access.hh
@@ -45,7 +45,7 @@
 /** return the value of what is pointed to in the packet. */
 template <typename T>
 inline T
-Packet::get()
+Packet::get() const
 {
     assert(flags.isSet(STATIC_DATA|DYNAMIC_DATA));
     assert(sizeof(T) <= size);
diff --git a/src/mem/ruby/common/DataBlock.cc b/src/mem/ruby/common/DataBlock.cc
index c71449dd0..2a292444a 100644
--- a/src/mem/ruby/common/DataBlock.cc
+++ b/src/mem/ruby/common/DataBlock.cc
@@ -78,7 +78,7 @@ DataBlock::getData(int offset, int len) const
 }
 
 void
-DataBlock::setData(uint8_t *data, int offset, int len)
+DataBlock::setData(const uint8_t *data, int offset, int len)
 {
     assert(offset + len <= RubySystem::getBlockSizeBytes());
     memcpy(&m_data[offset], data, len);
diff --git a/src/mem/ruby/common/DataBlock.hh b/src/mem/ruby/common/DataBlock.hh
index 56320523b..ac08fac82 100644
--- a/src/mem/ruby/common/DataBlock.hh
+++ b/src/mem/ruby/common/DataBlock.hh
@@ -59,7 +59,7 @@ class DataBlock
     uint8_t getByte(int whichByte) const;
     const uint8_t *getData(int offset, int len) const;
     void setByte(int whichByte, uint8_t data);
-    void setData(uint8_t *data, int offset, int len);
+    void setData(const uint8_t *data, int offset, int len);
     void copyPartial(const DataBlock & dblk, int offset, int len);
     bool equal(const DataBlock& obj) const;
     void print(std::ostream& out) const;
diff --git a/src/mem/ruby/slicc_interface/RubyRequest.cc b/src/mem/ruby/slicc_interface/RubyRequest.cc
index ff90e415e..e2f275006 100644
--- a/src/mem/ruby/slicc_interface/RubyRequest.cc
+++ b/src/mem/ruby/slicc_interface/RubyRequest.cc
@@ -72,7 +72,7 @@ RubyRequest::functionalWrite(Packet *pkt)
     Addr mBase = m_PhysicalAddress.getAddress();
     Addr mTail = mBase + m_Size;
 
-    uint8_t * pktData = pkt->getPtr<uint8_t>();
+    const uint8_t * pktData = pkt->getConstPtr<uint8_t>();
 
     Addr cBase = std::max(wBase, mBase);
     Addr cTail = std::min(wTail, mTail);
diff --git a/src/mem/ruby/slicc_interface/RubySlicc_Util.hh b/src/mem/ruby/slicc_interface/RubySlicc_Util.hh
index 8e2a1c5b1..dd9a1f2a4 100644
--- a/src/mem/ruby/slicc_interface/RubySlicc_Util.hh
+++ b/src/mem/ruby/slicc_interface/RubySlicc_Util.hh
@@ -135,7 +135,7 @@ testAndWrite(Address addr, DataBlock& blk, Packet *pkt)
     lineAddr.makeLineAddress();
 
     if (pktLineAddr == lineAddr) {
-        uint8_t *data = pkt->getPtr<uint8_t>();
+        const uint8_t *data = pkt->getConstPtr<uint8_t>();
         unsigned int size_in_bytes = pkt->getSize();
         unsigned startByte = pkt->getAddr() - lineAddr.getAddress();
 
diff --git a/src/mem/ruby/system/Sequencer.cc b/src/mem/ruby/system/Sequencer.cc
index 281ea22be..ef1b9676b 100644
--- a/src/mem/ruby/system/Sequencer.cc
+++ b/src/mem/ruby/system/Sequencer.cc
@@ -526,7 +526,7 @@ Sequencer::hitCallback(SequencerRequest* srequest, DataBlock& data,
 
     // update the data unless it is a non-data-carrying flush
     if (g_system_ptr->m_warmup_enabled) {
-        data.setData(pkt->getPtr<uint8_t>(),
+        data.setData(pkt->getConstPtr<uint8_t>(),
                      request_address.getOffset(), pkt->getSize());
     } else if (!pkt->isFlush()) {
         if ((type == RubyRequestType_LD) ||
@@ -538,7 +538,7 @@ Sequencer::hitCallback(SequencerRequest* srequest, DataBlock& data,
                    data.getData(request_address.getOffset(), pkt->getSize()),
                    pkt->getSize());
         } else {
-            data.setData(pkt->getPtr<uint8_t>(),
+            data.setData(pkt->getConstPtr<uint8_t>(),
                          request_address.getOffset(), pkt->getSize());
         }
     }