From 86777c9db174c74be49667bce3dda99f8ba23696 Mon Sep 17 00:00:00 2001
From: Steve Reinhardt <stever@eecs.umich.edu>
Date: Thu, 18 May 2006 22:54:19 -0400
Subject: [PATCH] First steps toward getting full system to work with
 TimingSimpleCPU.  Not there yet.

cpu/simple/atomic.cc:
    Only read SC result if store was an SC.
    Don't fake SC here; fake it in PhysicalMemory so
    all CPU models can share in the joy.
cpu/simple/timing.cc:
    Don't forget to checkForInterrupts().
    Only fetch subsequent instruction if we're still running
    (i.e. not quiesced).
dev/io_device.hh:
    Initialize port pointer in SendEvent object.
mem/physical.cc:
    Move fake SC "implementation" here from AtomicSimpleCPU.
mem/request.hh:
    Initialize flags to all clear, not uninitialized.
    Otherwise we can't reliably look at flags w/o explicitly
    setting them every time we create a request.

--HG--
extra : convert_revision : ae7601ce6fb54c54e19848aa5391327f9a6e61a6
---
 cpu/simple/atomic.cc | 12 ++++--------
 cpu/simple/timing.cc | 13 ++++++++++++-
 dev/io_device.hh     |  2 +-
 mem/physical.cc      |  5 +++++
 mem/request.hh       |  2 --
 5 files changed, 22 insertions(+), 12 deletions(-)

diff --git a/cpu/simple/atomic.cc b/cpu/simple/atomic.cc
index c09f16ada..e9422b9c0 100644
--- a/cpu/simple/atomic.cc
+++ b/cpu/simple/atomic.cc
@@ -349,20 +349,16 @@ AtomicSimpleCPU::write(T data, Addr addr, unsigned flags, uint64_t *res)
         dcache_access = true;
 
         assert(data_write_pkt->result == Success);
-    }
 
-    if (res && (fault == NoFault))
-        *res = data_write_pkt->result;
+        if (res && data_write_req->getFlags() & LOCKED) {
+            *res = data_write_req->getScResult();
+        }
+    }
 
     // This will need a new way to tell if it's hooked up to a cache or not.
     if (data_write_req->getFlags() & UNCACHEABLE)
         recordEvent("Uncached Write");
 
-    // @todo this is a hack and only works on uniprocessor systems
-    // some one else can implement LL/SC.
-    if (data_write_req->getFlags() & LOCKED)
-        *res = 1;
-
     // If the write needs to have a fault on the access, consider calling
     // changeStatus() and changing it to "bad addr write" or something.
     return fault;
diff --git a/cpu/simple/timing.cc b/cpu/simple/timing.cc
index 80d3380a5..70b88c4b1 100644
--- a/cpu/simple/timing.cc
+++ b/cpu/simple/timing.cc
@@ -75,6 +75,9 @@ TimingSimpleCPU::CpuPort::recvFunctional(Packet *pkt)
 void
 TimingSimpleCPU::CpuPort::recvStatusChange(Status status)
 {
+    if (status == RangeChange)
+        return;
+
     panic("TimingSimpleCPU doesn't expect recvStatusChange callback!");
 }
 
@@ -342,6 +345,8 @@ TimingSimpleCPU::write(int32_t data, Addr addr, unsigned flags, uint64_t *res)
 void
 TimingSimpleCPU::fetch()
 {
+    checkForInterrupts();
+
     Request *ifetch_req = new Request(true);
     ifetch_req->setSize(sizeof(MachInst));
 
@@ -380,7 +385,12 @@ TimingSimpleCPU::completeInst(Fault fault)
 
     advancePC(fault);
 
-    fetch();
+    if (_status == Running) {
+        // kick off fetch of next instruction... callback from icache
+        // response will cause that instruction to be executed,
+        // keeping the CPU running.
+        fetch();
+    }
 }
 
 
@@ -397,6 +407,7 @@ TimingSimpleCPU::completeIfetch()
         Fault fault = curStaticInst->initiateAcc(this, traceData);
         assert(fault == NoFault);
         assert(_status == DcacheWaitResponse);
+        // instruction will complete in dcache response callback
     } else {
         // non-memory instruction: execute completely now
         Fault fault = curStaticInst->execute(this, traceData);
diff --git a/dev/io_device.hh b/dev/io_device.hh
index 8b23422dd..6efa9ef63 100644
--- a/dev/io_device.hh
+++ b/dev/io_device.hh
@@ -90,7 +90,7 @@ class PioPort : public Port
         Packet *packet;
 
         SendEvent(PioPort *p, Packet *pkt, Tick t)
-            : Event(&mainEventQueue), packet(pkt)
+            : Event(&mainEventQueue), port(p), packet(pkt)
         { schedule(curTick + t); }
 
         virtual void process();
diff --git a/mem/physical.cc b/mem/physical.cc
index 8de9c3203..bc2500678 100644
--- a/mem/physical.cc
+++ b/mem/physical.cc
@@ -155,6 +155,11 @@ PhysicalMemory::doFunctionalAccess(Packet *pkt)
       case Write:
         memcpy(pmem_addr + pkt->addr - base_addr, pkt->getPtr<uint8_t>(),
                 pkt->size);
+        // temporary hack: will need to add real LL/SC implementation
+        // for cacheless systems later.
+        if (pkt->req->getFlags() & LOCKED) {
+            pkt->req->setScResult(1);
+        }
         break;
       default:
         panic("unimplemented");
diff --git a/mem/request.hh b/mem/request.hh
index 903e7503c..2db7b7779 100644
--- a/mem/request.hh
+++ b/mem/request.hh
@@ -97,8 +97,6 @@ class Request
 
     /** Flag structure for the request. */
     uint32_t flags;
-    /** Wether or not flags is valid (has been written yet). */
-    bool validFlags;
 
 //Accsesors for non-cpu request fields
   public: