CPU: Round-two unifying instr/data CPU ports across models

This patch continues the unification of how the different CPU models
create and share their instruction and data ports. Most importantly,
it forces every CPU to have an instruction and a data port, and gives
these ports explicit getters in the BaseCPU (getDataPort and
getInstPort). The patch helps in simplifying the code, make
assumptions more explicit, andfurther ease future patches related to
the CPU ports.

The biggest changes are in the in-order model (that was not modified
in the previous unification patch), which now moves the ports from the
CacheUnit to the CPU. It also distinguishes the instruction fetch and
load-store unit from the rest of the resources, and avoids the use of
indices and casting in favour of keeping track of these two units
explicitly (since they are always there anyways). The atomic, timing
and O3 model simply return references to their already existing ports.

1 files changed, 2 insertions, 5 deletions

diff --git a/src/cpu/o3/cpu.hh b/src/cpu/o3/cpu.hh
index 1c713097a..f48c0f0f2 100644
--- a/src/cpu/o3/cpu.hh
+++ b/src/cpu/o3/cpu.hh
@@ -361,9 +361,6 @@ class FullO3CPU : public BaseO3CPU
         this->dtb->demapPage(vaddr, asn);
     }
 
-    /** Returns a specific port. */
-    Port *getPort(const std::string &if_name, int idx);
-
     /** Ticks CPU, calling tick() on each stage, and checking the overall
      *  activity to see if the CPU should deschedule itself.
      */
@@ -781,10 +778,10 @@ class FullO3CPU : public BaseO3CPU
     }
 
     /** Used by the fetch unit to get a hold of the instruction port. */
-    Port* getIcachePort() { return &icachePort; }
+    virtual CpuPort &getInstPort() { return icachePort; }
 
     /** Get the dcache port (used to find block size for translations). */
-    Port* getDcachePort() { return &dcachePort; }
+    virtual CpuPort &getDataPort() { return dcachePort; }
 
     Addr lockAddr;