security challenge

[to_kallon]

i'm interested in adding a secure operating system to an predefined hardware architecture (given below) but all of the posts i've seen were for handhelds and the like, i'm looking to use gentoo secure over the following architecture:

IBM 405EP microprocessor
Processor Speed
266MHz
OS Support
Linux
Boot Loader
U-Boot
Real Time Clock
Battery Backed
Temperature Rating
0 to 65C; Industrial Available
Memory
ROM
32MB StrataFlash
RAM
32MB SDRAM
Connectivity
Serial Ports
2 RS232 Serial Ports
Ethernet
Dual 10/100Base-T RJ45

from what i've read it's just a matter of setting up gcc properly, but i'm fairly new to gentoo in general and configuring gcc is something i've never done before.
help very appreciated, thanks.