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.

4 files changed, 0 insertions, 5 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));