Linux Operating System Source Code: IBM Patches

I stumbled upon this code when I was trying to get an early printk 
working for 386.  There is a real need for things to be able to parse 
the command line in setup_arch(), for many architectures.

parse_options() no longer runs the setup functions, it only parses.
It may be called more than once with no ill effects.  This way it can 
be called in setup_arch(), then again in the generic start_kernel().

run_setup() comes along later and actually runs the __setup functions.
   It can do this in many phases, as long as parse_options() is called
first.  The last run_setup() is special because it goes through and
picks up all of the environment variables and init arguments that are
left over, setting them with setup_setenv()