mem: Remove redundant Packet::allocate calls

This patch cleans up the packet memory allocation confusion. The data
is always allocated at the requesting side, when a packet is created
(or copied), and there is never a need for any device to allocate any
space if it is merely responding to a paket. This behaviour is in line
with how SystemC and TLM works as well, thus increasing
interoperability, and matching established conventions.

The redundant calls to Packet::allocate are removed, and the checks in
the function are tightened up to make sure data is only ever allocated
once. There are still some oddities in the packet copy constructor
where we copy the data pointer if it is static (without ownership),
and allocate new space if the data is dynamic (with ownership). The
latter is being worked on further in a follow-on patch.

35 files changed, 6 insertions, 72 deletions

diff --git a/src/dev/alpha/backdoor.cc b/src/dev/alpha/backdoor.cc
index dc0e8e49f..598620893 100644
--- a/src/dev/alpha/backdoor.cc
+++ b/src/dev/alpha/backdoor.cc
@@ -111,7 +111,6 @@ AlphaBackdoor::read(PacketPtr pkt)
 
     Addr daddr = pkt->getAddr() - pioAddr;
 
-    pkt->allocate();
     pkt->makeAtomicResponse();
 
     switch (pkt->getSize())
diff --git a/src/dev/alpha/tsunami_cchip.cc b/src/dev/alpha/tsunami_cchip.cc
index 203325e75..7416de403 100644
--- a/src/dev/alpha/tsunami_cchip.cc
+++ b/src/dev/alpha/tsunami_cchip.cc
@@ -83,7 +83,6 @@ TsunamiCChip::read(PacketPtr pkt)
     Addr regnum = (pkt->getAddr() - pioAddr) >> 6;
     Addr daddr = (pkt->getAddr() - pioAddr);
 
-    pkt->allocate();
     switch (pkt->getSize()) {
 
       case sizeof(uint64_t):
diff --git a/src/dev/alpha/tsunami_io.cc b/src/dev/alpha/tsunami_io.cc
index 6586cd980..2c503880f 100644
--- a/src/dev/alpha/tsunami_io.cc
+++ b/src/dev/alpha/tsunami_io.cc
@@ -96,8 +96,6 @@ TsunamiIO::read(PacketPtr pkt)
     DPRINTF(Tsunami, "io read  va=%#x size=%d IOPorrt=%#x\n", pkt->getAddr(),
             pkt->getSize(), daddr);
 
-    pkt->allocate();
-
     if (pkt->getSize() == sizeof(uint8_t)) {
         switch(daddr) {
           // PIC1 mask read
diff --git a/src/dev/alpha/tsunami_pchip.cc b/src/dev/alpha/tsunami_pchip.cc
index 3ddc0f1b3..328699f9f 100644
--- a/src/dev/alpha/tsunami_pchip.cc
+++ b/src/dev/alpha/tsunami_pchip.cc
@@ -72,7 +72,6 @@ TsunamiPChip::read(PacketPtr pkt)
 {
     assert(pkt->getAddr() >= pioAddr && pkt->getAddr() < pioAddr + pioSize);
 
-    pkt->allocate();
     Addr daddr = (pkt->getAddr() - pioAddr) >> 6;;
     assert(pkt->getSize() == sizeof(uint64_t));
 
diff --git a/src/dev/arm/a9scu.cc b/src/dev/arm/a9scu.cc
index dc012a036..26b2a4522 100644
--- a/src/dev/arm/a9scu.cc
+++ b/src/dev/arm/a9scu.cc
@@ -55,7 +55,6 @@ A9SCU::read(PacketPtr pkt)
     assert(pkt->getAddr() >= pioAddr && pkt->getAddr() < pioAddr + pioSize);
     assert(pkt->getSize() == 4);
     Addr daddr = pkt->getAddr() - pioAddr;
-    pkt->allocate();
 
     switch(daddr) {
       case Control:
diff --git a/src/dev/arm/amba_device.cc b/src/dev/arm/amba_device.cc
index d2333417f..0ba20d087 100644
--- a/src/dev/arm/amba_device.cc
+++ b/src/dev/arm/amba_device.cc
@@ -76,8 +76,6 @@ AmbaDevice::readId(PacketPtr pkt, uint64_t amba_id, Addr pio_addr)
     if (daddr < AMBA_PER_ID0 || daddr > AMBA_CEL_ID3)
         return false;
 
-    pkt->allocate();
-
     int byte = (daddr - AMBA_PER_ID0) << 1;
     // Too noisy right now
     DPRINTF(AMBA, "Returning %#x for offset %#x(%d)\n",
diff --git a/src/dev/arm/amba_fake.cc b/src/dev/arm/amba_fake.cc
index 3ca705c6c..d415ab2fa 100644
--- a/src/dev/arm/amba_fake.cc
+++ b/src/dev/arm/amba_fake.cc
@@ -57,7 +57,6 @@ AmbaFake::read(PacketPtr pkt)
     assert(pkt->getAddr() >= pioAddr && pkt->getAddr() < pioAddr + pioSize);
 
     Addr daddr = pkt->getAddr() - pioAddr;
-    pkt->allocate();
 
     DPRINTF(AMBA, " read register %#x\n", daddr);
 
@@ -74,7 +73,6 @@ AmbaFake::write(PacketPtr pkt)
 {
 
     Addr daddr = pkt->getAddr() - pioAddr;
-    pkt->allocate();
 
     if (!params()->ignore_access)
         panic("Tried to write AmbaFake at offset %#x that doesn't exist\n", daddr);
diff --git a/src/dev/arm/energy_ctrl.cc b/src/dev/arm/energy_ctrl.cc
index cbfa5aa79..b77eaba3b 100644
--- a/src/dev/arm/energy_ctrl.cc
+++ b/src/dev/arm/energy_ctrl.cc
@@ -64,7 +64,6 @@ EnergyCtrl::read(PacketPtr pkt)
 {
     assert(pkt->getAddr() >= pioAddr && pkt->getAddr() < pioAddr + pioSize);
     assert(pkt->getSize() == 4);
-    pkt->allocate();
 
     Addr daddr = pkt->getAddr() - pioAddr;
     assert((daddr & 3) == 0);
diff --git a/src/dev/arm/gic_pl390.cc b/src/dev/arm/gic_pl390.cc
index b93cdd028..019b3ee8b 100644
--- a/src/dev/arm/gic_pl390.cc
+++ b/src/dev/arm/gic_pl390.cc
@@ -150,7 +150,6 @@ Tick
 Pl390::readDistributor(PacketPtr pkt)
 {
     Addr daddr = pkt->getAddr() - distAddr;
-    pkt->allocate();
 
     int ctx_id = pkt->req->contextId();
 
@@ -284,7 +283,6 @@ Tick
 Pl390::readCpu(PacketPtr pkt)
 {
     Addr daddr = pkt->getAddr() - cpuAddr;
-    pkt->allocate();
 
     assert(pkt->req->hasContextId());
     int ctx_id = pkt->req->contextId();
@@ -369,7 +367,6 @@ Tick
 Pl390::readMsix(PacketPtr pkt)
 {
     Addr daddr = pkt->getAddr() - msixRegAddr;
-    pkt->allocate();
 
     DPRINTF(GIC, "Gic MSIX read register %#x\n", daddr);
 
@@ -390,7 +387,6 @@ Tick
 Pl390::writeDistributor(PacketPtr pkt)
 {
     Addr daddr = pkt->getAddr() - distAddr;
-    pkt->allocate();
 
     assert(pkt->req->hasContextId());
     int ctx_id = pkt->req->contextId();
@@ -531,7 +527,6 @@ Tick
 Pl390::writeCpu(PacketPtr pkt)
 {
     Addr daddr = pkt->getAddr() - cpuAddr;
-    pkt->allocate();
 
     assert(pkt->req->hasContextId());
     int ctx_id = pkt->req->contextId();
@@ -586,7 +581,6 @@ Tick
 Pl390::writeMsix(PacketPtr pkt)
 {
     Addr daddr = pkt->getAddr() - msixRegAddr;
-    pkt->allocate();
 
     DPRINTF(GIC, "Gic MSI-X write register %#x data %d\n",
                  daddr, pkt->get<uint32_t>());
diff --git a/src/dev/arm/hdlcd.cc b/src/dev/arm/hdlcd.cc
index 349b246c2..37569b22b 100644
--- a/src/dev/arm/hdlcd.cc
+++ b/src/dev/arm/hdlcd.cc
@@ -104,8 +104,6 @@ HDLcd::read(PacketPtr pkt)
             pkt->getAddr() < pioAddr + pioSize &&
             pkt->getSize() == 4);
 
-    pkt->allocate();
-
     switch (daddr) {
       case Version:
         data = version;
diff --git a/src/dev/arm/kmi.cc b/src/dev/arm/kmi.cc
index 99d61c610..2344b4cb5 100644
--- a/src/dev/arm/kmi.cc
+++ b/src/dev/arm/kmi.cc
@@ -69,8 +69,6 @@ Pl050::read(PacketPtr pkt)
     assert(pkt->getAddr() >= pioAddr && pkt->getAddr() < pioAddr + pioSize);
 
     Addr daddr = pkt->getAddr() - pioAddr;
-    pkt->allocate();
-
 
     uint32_t data = 0;
 
diff --git a/src/dev/arm/pl011.cc b/src/dev/arm/pl011.cc
index b47d0e9fb..d690ee9cb 100644
--- a/src/dev/arm/pl011.cc
+++ b/src/dev/arm/pl011.cc
@@ -64,7 +64,6 @@ Pl011::read(PacketPtr pkt)
     assert(pkt->getAddr() >= pioAddr && pkt->getAddr() < pioAddr + pioSize);
 
     Addr daddr = pkt->getAddr() - pioAddr;
-    pkt->allocate();
 
     DPRINTF(Uart, " read register %#x size=%d\n", daddr, pkt->getSize());
 
diff --git a/src/dev/arm/pl111.cc b/src/dev/arm/pl111.cc
index 4d1bcba1e..a5b9b412c 100644
--- a/src/dev/arm/pl111.cc
+++ b/src/dev/arm/pl111.cc
@@ -104,7 +104,6 @@ Pl111::read(PacketPtr pkt)
            pkt->getAddr() < pioAddr + pioSize);
 
     Addr daddr = pkt->getAddr() - pioAddr;
-    pkt->allocate();
 
     DPRINTF(PL111, " read register %#x size=%d\n", daddr, pkt->getSize());
 
diff --git a/src/dev/arm/rtc_pl031.cc b/src/dev/arm/rtc_pl031.cc
index 8f421a1da..a43ac6271 100644
--- a/src/dev/arm/rtc_pl031.cc
+++ b/src/dev/arm/rtc_pl031.cc
@@ -62,7 +62,6 @@ PL031::read(PacketPtr pkt)
     assert(pkt->getAddr() >= pioAddr && pkt->getAddr() < pioAddr + pioSize);
     assert(pkt->getSize() == 4);
     Addr daddr = pkt->getAddr() - pioAddr;
-    pkt->allocate();
     uint32_t data;
 
     DPRINTF(Timer, "Reading from RTC at offset: %#x\n", daddr);
@@ -125,7 +124,6 @@ PL031::write(PacketPtr pkt)
     assert(pkt->getAddr() >= pioAddr && pkt->getAddr() < pioAddr + pioSize);
     assert(pkt->getSize() == 4);
     Addr daddr = pkt->getAddr() - pioAddr;
-    pkt->allocate();
     DPRINTF(Timer, "Writing to RTC at offset: %#x\n", daddr);
 
     switch (daddr) {
diff --git a/src/dev/arm/rv_ctrl.cc b/src/dev/arm/rv_ctrl.cc
index af121861c..f2b85d513 100644
--- a/src/dev/arm/rv_ctrl.cc
+++ b/src/dev/arm/rv_ctrl.cc
@@ -54,7 +54,6 @@ RealViewCtrl::read(PacketPtr pkt)
     assert(pkt->getAddr() >= pioAddr && pkt->getAddr() < pioAddr + pioSize);
     assert(pkt->getSize() == 4);
     Addr daddr = pkt->getAddr() - pioAddr;
-    pkt->allocate();
 
     switch(daddr) {
       case ProcId0:
diff --git a/src/dev/arm/timer_cpulocal.cc b/src/dev/arm/timer_cpulocal.cc
index ae341e2be..de2f99f0a 100644
--- a/src/dev/arm/timer_cpulocal.cc
+++ b/src/dev/arm/timer_cpulocal.cc
@@ -75,7 +75,6 @@ CpuLocalTimer::read(PacketPtr pkt)
     assert(pkt->getAddr() >= pioAddr && pkt->getAddr() < pioAddr + pioSize);
     assert(pkt->getSize() == 4);
     Addr daddr = pkt->getAddr() - pioAddr;
-    pkt->allocate();
     int cpu_id = pkt->req->contextId();
     DPRINTF(Timer, "Reading from CpuLocalTimer at offset: %#x\n", daddr);
     assert(cpu_id >= 0);
@@ -154,7 +153,6 @@ CpuLocalTimer::write(PacketPtr pkt)
     assert(pkt->getAddr() >= pioAddr && pkt->getAddr() < pioAddr + pioSize);
     assert(pkt->getSize() == 4);
     Addr daddr = pkt->getAddr() - pioAddr;
-    pkt->allocate();
     int cpu_id = pkt->req->contextId();
     DPRINTF(Timer, "Writing to CpuLocalTimer at offset: %#x\n", daddr);
     assert(cpu_id >= 0);
diff --git a/src/dev/arm/timer_sp804.cc b/src/dev/arm/timer_sp804.cc
index 25bc08003..9f7867107 100644
--- a/src/dev/arm/timer_sp804.cc
+++ b/src/dev/arm/timer_sp804.cc
@@ -66,7 +66,6 @@ Sp804::read(PacketPtr pkt)
     assert(pkt->getAddr() >= pioAddr && pkt->getAddr() < pioAddr + pioSize);
     assert(pkt->getSize() == 4);
     Addr daddr = pkt->getAddr() - pioAddr;
-    pkt->allocate();
     DPRINTF(Timer, "Reading from DualTimer at offset: %#x\n", daddr);
 
     if (daddr < Timer::Size)
@@ -121,7 +120,6 @@ Sp804::write(PacketPtr pkt)
     assert(pkt->getAddr() >= pioAddr && pkt->getAddr() < pioAddr + pioSize);
     assert(pkt->getSize() == 4);
     Addr daddr = pkt->getAddr() - pioAddr;
-    pkt->allocate();
     DPRINTF(Timer, "Writing to DualTimer at offset: %#x\n", daddr);
 
     if (daddr < Timer::Size)
diff --git a/src/dev/arm/vgic.cc b/src/dev/arm/vgic.cc
index 2faf2030e..4a63c796a 100644
--- a/src/dev/arm/vgic.cc
+++ b/src/dev/arm/vgic.cc
@@ -92,7 +92,6 @@ Tick
 VGic::readVCpu(PacketPtr pkt)
 {
     Addr daddr = pkt->getAddr() - vcpuAddr;
-    pkt->allocate();
 
     int ctx_id = pkt->req->contextId();
     assert(ctx_id < VGIC_CPU_MAX);
@@ -137,7 +136,6 @@ Tick
 VGic::readCtrl(PacketPtr pkt)
 {
     Addr daddr = pkt->getAddr() - hvAddr;
-    pkt->allocate();
 
     int ctx_id = pkt->req->contextId();
 
@@ -232,7 +230,6 @@ Tick
 VGic::writeVCpu(PacketPtr pkt)
 {
     Addr daddr = pkt->getAddr() - vcpuAddr;
-    pkt->allocate();
 
     int ctx_id = pkt->req->contextId();
     assert(ctx_id < VGIC_CPU_MAX);
@@ -280,7 +277,6 @@ Tick
 VGic::writeCtrl(PacketPtr pkt)
 {
     Addr daddr = pkt->getAddr() - hvAddr;
-    pkt->allocate();
 
     int ctx_id = pkt->req->contextId();
 
diff --git a/src/dev/copy_engine.cc b/src/dev/copy_engine.cc
index e4cd90c1c..a3d73b634 100644
--- a/src/dev/copy_engine.cc
+++ b/src/dev/copy_engine.cc
@@ -182,8 +182,6 @@ CopyEngine::read(PacketPtr pkt)
 
     DPRINTF(DMACopyEngine, "Read device register %#X size: %d\n", daddr, size);
 
-    pkt->allocate();
-
     ///
     /// Handle read of register here
     ///
diff --git a/src/dev/i8254xGBe.cc b/src/dev/i8254xGBe.cc
index af9734761..70dba7c22 100644
--- a/src/dev/i8254xGBe.cc
+++ b/src/dev/i8254xGBe.cc
@@ -183,8 +183,6 @@ IGbE::read(PacketPtr pkt)
 
     DPRINTF(Ethernet, "Read device register %#X\n", daddr);
 
-    pkt->allocate();
-
     //
     // Handle read of register here
     //
diff --git a/src/dev/ide_ctrl.cc b/src/dev/ide_ctrl.cc
index bbc0e379d..27757529a 100644
--- a/src/dev/ide_ctrl.cc
+++ b/src/dev/ide_ctrl.cc
@@ -172,8 +172,6 @@ IdeController::readConfig(PacketPtr pkt)
         return PciDevice::readConfig(pkt);
     }
 
-    pkt->allocate();
-
     switch (pkt->getSize()) {
       case sizeof(uint8_t):
         switch (offset) {
@@ -462,7 +460,6 @@ IdeController::Channel::accessBMI(Addr offset,
 void
 IdeController::dispatchAccess(PacketPtr pkt, bool read)
 {
-    pkt->allocate();
     if (pkt->getSize() != 1 && pkt->getSize() != 2 && pkt->getSize() !=4)
          panic("Bad IDE read size: %d\n", pkt->getSize());
 
diff --git a/src/dev/isa_fake.cc b/src/dev/isa_fake.cc
index 235dc3098..0871fecbb 100644
--- a/src/dev/isa_fake.cc
+++ b/src/dev/isa_fake.cc
@@ -53,7 +53,6 @@ IsaFake::IsaFake(Params *p)
 Tick
 IsaFake::read(PacketPtr pkt)
 {
-    pkt->allocate();
     pkt->makeAtomicResponse();
 
     if (params()->warn_access != "")
diff --git a/src/dev/mips/malta_cchip.cc b/src/dev/mips/malta_cchip.cc
index fe3336435..dc5211122 100755
--- a/src/dev/mips/malta_cchip.cc
+++ b/src/dev/mips/malta_cchip.cc
@@ -78,7 +78,6 @@ MaltaCChip::read(PacketPtr pkt)
     Addr regnum = (pkt->getAddr() - pioAddr) >> 6;
     Addr daddr = (pkt->getAddr() - pioAddr);
 
-    pkt->allocate();
     switch (pkt->getSize()) {
 
       case sizeof(uint64_t):
diff --git a/src/dev/mips/malta_pchip.cc b/src/dev/mips/malta_pchip.cc
index 37aaa1b5a..bee61fddd 100755
--- a/src/dev/mips/malta_pchip.cc
+++ b/src/dev/mips/malta_pchip.cc
@@ -71,7 +71,6 @@ MaltaPChip::read(PacketPtr pkt)
 {
     assert(pkt->getAddr() >= pioAddr && pkt->getAddr() < pioAddr + pioSize);
 
-    pkt->allocate();
     Addr daddr = (pkt->getAddr() - pioAddr) >> 6;;
     assert(pkt->getSize() == sizeof(uint64_t));
 
diff --git a/src/dev/ns_gige.cc b/src/dev/ns_gige.cc
index 239babe70..d87975759 100644
--- a/src/dev/ns_gige.cc
+++ b/src/dev/ns_gige.cc
@@ -186,8 +186,6 @@ NSGigE::read(PacketPtr pkt)
 {
     assert(ioEnable);
 
-    pkt->allocate();
-
     //The mask is to give you only the offset into the device register file
     Addr daddr = pkt->getAddr() & 0xfff;
     DPRINTF(EthernetPIO, "read  da=%#x pa=%#x size=%d\n",
diff --git a/src/dev/pciconfigall.cc b/src/dev/pciconfigall.cc
index b0da01f0b..882366a42 100644
--- a/src/dev/pciconfigall.cc
+++ b/src/dev/pciconfigall.cc
@@ -55,9 +55,6 @@ PciConfigAll::PciConfigAll(const Params *p)
 Tick
 PciConfigAll::read(PacketPtr pkt)
 {
-
-    pkt->allocate();
-
     DPRINTF(PciConfigAll, "read  va=%#x size=%d\n", pkt->getAddr(),
             pkt->getSize());
 
diff --git a/src/dev/pcidev.cc b/src/dev/pcidev.cc
index 232aa9e8b..715b67603 100644
--- a/src/dev/pcidev.cc
+++ b/src/dev/pcidev.cc
@@ -294,10 +294,6 @@ PciDevice::readConfig(PacketPtr pkt)
         panic("Out-of-range access to PCI config space!\n");
     }
 
-
-
-    pkt->allocate();
-
     switch (pkt->getSize()) {
       case sizeof(uint8_t):
         pkt->set<uint8_t>(config.data[offset]);
diff --git a/src/dev/sinic.cc b/src/dev/sinic.cc
index 798fb17ef..a5608fb36 100644
--- a/src/dev/sinic.cc
+++ b/src/dev/sinic.cc
@@ -225,8 +225,6 @@ Device::read(PacketPtr pkt)
     Addr index = daddr >> Regs::VirtualShift;
     Addr raddr = daddr & Regs::VirtualMask;
 
-    pkt->allocate();
-
     if (!regValid(raddr))
         panic("invalid register: cpu=%d vnic=%d da=%#x pa=%#x size=%d",
               cpu, index, daddr, pkt->getAddr(), pkt->getSize());
diff --git a/src/dev/sparc/dtod.cc b/src/dev/sparc/dtod.cc
index 94a32bed4..3853abb16 100644
--- a/src/dev/sparc/dtod.cc
+++ b/src/dev/sparc/dtod.cc
@@ -65,7 +65,6 @@ DumbTOD::read(PacketPtr pkt)
     assert(pkt->getAddr() >= pioAddr && pkt->getAddr() < pioAddr + pioSize);
     assert(pkt->getSize() == 8);
 
-    pkt->allocate();
     pkt->set(todTime);
     todTime += 1000;
 
diff --git a/src/dev/uart8250.cc b/src/dev/uart8250.cc
index 40ee7d38f..e840d2a56 100644
--- a/src/dev/uart8250.cc
+++ b/src/dev/uart8250.cc
@@ -113,7 +113,6 @@ Uart8250::read(PacketPtr pkt)
     assert(pkt->getSize() == 1);
 
     Addr daddr = pkt->getAddr() - pioAddr;
-    pkt->allocate();
 
     DPRINTF(Uart, " read register %#x\n", daddr);
 
diff --git a/src/dev/virtio/base.cc b/src/dev/virtio/base.cc
index 44cce65c4..06c6e3452 100644
--- a/src/dev/virtio/base.cc
+++ b/src/dev/virtio/base.cc
@@ -422,7 +422,6 @@ void
 VirtIODeviceBase::readConfigBlob(PacketPtr pkt, Addr cfgOffset, const uint8_t *cfg)
 {
     const unsigned size(pkt->getSize());
-    pkt->allocate();
 
     if (cfgOffset + size > configSize)
         panic("Config read out of bounds.\n");
@@ -434,7 +433,6 @@ void
 VirtIODeviceBase::writeConfigBlob(PacketPtr pkt, Addr cfgOffset, uint8_t *cfg)
 {
     const unsigned size(pkt->getSize());
-    pkt->allocate();
 
     if (cfgOffset + size > configSize)
         panic("Config write out of bounds.\n");
diff --git a/src/dev/virtio/pci.cc b/src/dev/virtio/pci.cc
index 1f99d7fe4..c77b61934 100644
--- a/src/dev/virtio/pci.cc
+++ b/src/dev/virtio/pci.cc
@@ -75,8 +75,6 @@ PciVirtIO::read(PacketPtr pkt)
         return 0;
     }
 
-    pkt->allocate();
-
     switch(offset) {
       case OFF_DEVICE_FEATURES:
         DPRINTF(VIOPci, "   DEVICE_FEATURES request\n");
@@ -153,8 +151,6 @@ PciVirtIO::write(PacketPtr pkt)
         return 0;
     }
 
-    pkt->allocate();
-
     switch(offset) {
       case OFF_DEVICE_FEATURES:
         warn("Guest tried to write device features.");
diff --git a/src/mem/cache/cache_impl.hh b/src/mem/cache/cache_impl.hh
index f4099c0ef..2eb38805c 100644
--- a/src/mem/cache/cache_impl.hh
+++ b/src/mem/cache/cache_impl.hh
@@ -1566,7 +1566,6 @@ doTimingSupplyResponse(PacketPtr req_pkt, const uint8_t *blk_data,
     // already made a copy...
     PacketPtr pkt = already_copied ? req_pkt : new Packet(req_pkt);
     assert(req_pkt->isInvalidate() || pkt->sharedAsserted());
-    pkt->allocate();
     pkt->makeTimingResponse();
     // @todo Make someone pay for this
     pkt->firstWordDelay = pkt->lastWordDelay = 0;
@@ -2018,7 +2017,6 @@ Cache<TagStore>::getTimingPacket()
             // make copy of current packet to forward, keep current
             // copy for response handling
             pkt = new Packet(tgt_pkt);
-            pkt->allocate();
             if (pkt->isWrite()) {
                 pkt->setData(tgt_pkt->getConstPtr<uint8_t>());
             }
diff --git a/src/mem/packet.cc b/src/mem/packet.cc
index 9dd67746b..758770824 100644
--- a/src/mem/packet.cc
+++ b/src/mem/packet.cc
@@ -204,7 +204,6 @@ Packet::checkFunctional(Printable *obj, Addr addr, bool is_secure, int size,
 
     if (isRead()) {
         if (func_start >= val_start && func_end <= val_end) {
-            allocate();
             memcpy(getPtr<uint8_t>(), data + offset, getSize());
             return true;
         } else {
diff --git a/src/mem/packet.hh b/src/mem/packet.hh
index b540ef6ca..e8fb00680 100644
--- a/src/mem/packet.hh
+++ b/src/mem/packet.hh
@@ -659,6 +659,11 @@ class Packet : public Printable
 
         flags.set(pkt->flags & (VALID_ADDR|VALID_SIZE));
         flags.set(pkt->flags & STATIC_DATA);
+
+        // if we did not copy the static data pointer, allocate data
+        // dynamically instead
+        if (!data)
+            allocate();
     }
 
     /**
@@ -942,15 +947,10 @@ class Packet : public Printable
         data = NULL;
     }
 
-    /** If there isn't data in the packet, allocate some. */
+    /** Allocate memory for the packet. */
     void
     allocate()
     {
-        if (data) {
-            assert(flags.isSet(STATIC_DATA|DYNAMIC_DATA));
-            return;
-        }
-
         assert(flags.noneSet(STATIC_DATA|DYNAMIC_DATA));
         flags.set(DYNAMIC_DATA|ARRAY_DATA);
         data = new uint8_t[getSize()];