[LinuxBIOS] a slight change to startup and elf images

[Ronald G Minnich]

Right now, we use mkelfimage to set up parameter blocks for linux. There 
is a lot of code to do this, and I am running out of room on OLPC. I 
need to build tiny elf images with on executable code in them (other 
than your kernel, of course).

I have modified mkelfimage so that it produces an elfimage with only 3 
segments: command line, kernel, initrd. With this option, you can build 
a very simple elfimage with just those three things.

There is the issue of setting up %esi for 386 linux. I am considering 
the following convention:

architecture-independent part (src/boot/)
For the first PT_LOAD elf segment, assume it is the command line. Set a 
variable, command_line, to the load address of this segment.

architecture-dependent, e.g. 386 (src/cpu/boot.c)
set %esi to command_line.

If you are using normal mkelfimage, this is a no-op: esi setting is 
ignored. If you are using mkelfimage with my option (e.g. OLPC), this 
address will be used as the command line pointer.

I can't see a problem, any comments?

thanks

ron