diff -r 5c80319895db -r 2b4a4101be69 configs/common/Benchmarks.py
--- a/configs/common/Benchmarks.py	Wed Jan 28 10:10:48 2015 +0000
+++ b/configs/common/Benchmarks.py	Fri Jan 16 14:12:03 2015 -0600
@@ -31,10 +31,11 @@
 from m5.defines import buildEnv
 
 class SysConfig:
-    def __init__(self, script=None, mem=None, disk=None):
+    def __init__(self, script=None, mem=None, disk=None, rootdev=None):
         self.scriptname = script
         self.diskname = disk
         self.memsize = mem
+        self.root = rootdev
 
     def script(self):
         if self.scriptname:
@@ -62,6 +63,12 @@
                 buildEnv['TARGET_ISA']
             exit(1)
 
+    def rootdev(self):
+        if self.root:
+            return self.root
+        else:
+            return '/dev/sda1'
+
 # Benchmarks are defined as a key in a dict which is a list of SysConfigs
 # The first defined machine is the test system, the others are driving systems
 
diff -r 5c80319895db -r 2b4a4101be69 configs/common/FSConfig.py
--- a/configs/common/FSConfig.py	Wed Jan 28 10:10:48 2015 +0000
+++ b/configs/common/FSConfig.py	Fri Jan 16 14:12:03 2015 -0600
@@ -57,6 +57,7 @@
 
 def fillInCmdline(mdesc, template, **kwargs):
     kwargs.setdefault('disk', mdesc.disk())
+    kwargs.setdefault('rootdev', mdesc.rootdev())
     kwargs.setdefault('mem', mdesc.mem())
     kwargs.setdefault('script', mdesc.script())
     return template % kwargs
@@ -279,7 +280,7 @@
         if not cmdline:
             cmdline = 'earlyprintk=pl011,0x1c090000 console=ttyAMA0 ' + \
                       'lpj=19988480 norandmaps rw loglevel=8 ' + \
-                      'mem=%(mem)s root=/dev/sda1'
+                      'mem=%(mem)s root=%(rootdev)s'
 
         self.realview.setupBootLoader(self.membus, self, binary)
         self.gic_cpu_addr = self.realview.gic.cpu_addr
diff -r 5c80319895db -r 2b4a4101be69 configs/common/Options.py
--- a/configs/common/Options.py	Wed Jan 28 10:10:48 2015 +0000
+++ b/configs/common/Options.py	Fri Jan 16 14:12:03 2015 -0600
@@ -274,6 +274,8 @@
     # Disk Image Options
     parser.add_option("--disk-image", action="store", type="string", default=None,
                       help="Path to the disk image to use.")
+    parser.add_option("--root-device", action="store", type="string", default=None,
+                      help="OS device name for root partition")
 
     # Command line options
     parser.add_option("--command-line", action="store", type="string",
diff -r 5c80319895db -r 2b4a4101be69 configs/example/fs.py
--- a/configs/example/fs.py	Wed Jan 28 10:10:48 2015 +0000
+++ b/configs/example/fs.py	Fri Jan 16 14:12:03 2015 -0600
@@ -313,10 +313,13 @@
         sys.exit(1)
 else:
     if options.dual:
-        bm = [SysConfig(disk=options.disk_image, mem=options.mem_size),
-              SysConfig(disk=options.disk_image, mem=options.mem_size)]
+        bm = [SysConfig(disk=options.disk_image, rootdev=options.root_device,
+                        mem=options.mem_size),
+              SysConfig(disk=options.disk_image, rootdev=options.root_device,
+                        mem=options.mem_size)]
     else:
-        bm = [SysConfig(disk=options.disk_image, mem=options.mem_size)]
+        bm = [SysConfig(disk=options.disk_image, rootdev=options.root_device,
+                        mem=options.mem_size)]
 
 np = options.num_cpus