(bios) stage and that bootloader stage when we have a nice lilo/grub prompt.
to enable it in kernel, say “yes” in Processor type and features->kexec system call (EXPERIMENTAL)
make and install your kernel.
we will need also a userspace tool called kexec. at the moment of writing, it is not available as package for debian sarge, but is for etch; the sources can be built and installed without any problems, so i don’t see any problems in downloading it from let’s say http://packages.debian.org/testing/source/kexec-tools; i tested them even with slackware and everything worked perfectly.
to boot with kexec we need first to load a kernel image in memory:
and then to execute the reboot:
the problem is that here we oversimplify things: we do not term and kill processes, we do not umount filesystems. to make everything to work properly, we just modify /etc/init.d/reboot to look like this:
at this moment we have kexec basically working.