More progress toward actually running a program.

See configs/test.py for test config (using simple
binary in my home directory on zizzer).

base/chunk_generator.hh:
    Fix assertion for chunkSize == 0 (not a power of 2)
base/intmath.hh:
    Fix roundDown to take integer alignments.
cpu/base.cc:
    Register exec contexts regardless of state (not sure why
    this check was in here in the first place).
mem/physical.cc:
    Add breaks to switch.
python/m5/objects/BaseCPU.py:
    Default mem to Parent.any (e.g. get from System).
python/m5/objects/Ethernet.py:
python/m5/objects/Root.py:
    HierParams is gone.
python/m5/objects/PhysicalMemory.py:
    mmu param is full-system only.
sim/process.cc:
    Stack mapping request must be page-aligned and page-sized.
    Don't delete objFile object in create since we are counting
    on it being around for startup().

--HG--
extra : convert_revision : 90c43ee927e7d82a045d6e10302d965797d006f7

python/m5/objects/PhysicalMemory.py

@@ -5,4 +5,5 @@ class PhysicalMemory(Memory):
     type = 'PhysicalMemory'
     range = Param.AddrRange("Device Address")
     file = Param.String('', "memory mapped file")
-    mmu = Param.MemoryController(Parent.any, "Memory Controller")
+    if build_env['FULL_SYSTEM']:
+        mmu = Param.MemoryController(Parent.any, "Memory Controller")