Rename the current /usr/src/linux directory to something else (/usr/src/linux can be a symlink rather than an actual directory. Either way, rename it) by running:
mv /usr/src/linux /usr/src/linux-old
Remove /usr/include/linux and /usr/include/asm by running:
rm -r /usr/include/linux /usr/include/asm
Unpack the Kernel archive in the /usr/src/ directory (this will create a new /usr/src/linux directory)
Create the /usr/include/linux and /usr/include/asm symlinks by running:
cd /usr/include
ln -s ../src/linux/include/linux linux
ln -s ../src/linux/include/asm-<cpu> asm
Look in the /usr/src/linux/include directory and see which asm-* directories are present. Choose the correct one for your platform. If you're on an PPC platform, you'd run ln -s ../src/linux/include/asm-ppc asm
For USB PowerPC systems you need to apply the USP PPC Patch. The patch should be located in /usr/src and you can keep it gzipped:
cd /usr/src/linux
gzip -cd ../usb-2.3.50-1-for-2.2.14.diff.gz | patch -p1
make distclean
Before you configure the actual kernel you need to load the proper defaults for PowerPC. For USB Mac's, the USB you need to choose is OHCI. Do not enable UHCI. You will need to select USB Human Interface Device, the USB keyboard and the USB mouse. You load these defaults by running:
pmac_config
Choose a method to configure the kernel (see the README file for more details on configuration methods) and make sure you don't configure anything as modules at this point. This is because we won't have the necessary software available to load kernel modules for a while.
After you're done with your kernel configuration, check and set the dependencies by running:
make dep
Compile the kernel by running:
make vmlinux
Copy the vmlinux file to the /boot directory by running:
cp vmlinux /boot/lfskernel
Copy the entire kernel source tree to the LFS partition by running:
cp -av /usr/src/linux $LFS/usr/src
Create the $LFS/usr/include/linux and $LFS/usr/include/asm symlinks by running:
cd $LFS/usr/include
ln -s ../src/linux/include/linux linux
ln -s ../src/linux/include/asm asm