Introduction

AMD64, also known as x86_64, is the architecture of a family of processors from AMD, including Athlon64 and Opteron. These processors have a 64-bit instruction set of their own, and also offer compatibility with popular 32-bit processors using the ia32 architecture.

This document describes a way to build a basic GNU/Linux system with as much as possible compiled for the x86_64 architecture, but with the capability to build and run ia32 binaries as well. The techniques used are based heavily on LFS 5.0, which should be referenced for much of the background and reasoning for the techniques used in the build.

The assumption is that one is starting from a relatively up-to-date 32-bit GNU/Linux system (the author used Slackware Linux 9.1) and building on the machine with the x86_64 CPU(s).

The main differences between this build and the one described in LFS 5.0 are:

• A x86_64 cross compiler must be built first, and installed in the build host system.
• An x86_64 Linux kernel must also be built and installed in the host system.
• After building the base system, ia32 compatibility libraries must be built.
• A multilib capable gcc is built after the ia32 compatibility libraries.
• Neither GRUB nor LILO can be built natively for x86_64, so building GRUB is deferred until after the ia32 libraries.

Next: building the cross-compiling toolchain