> Date: Mon, 14 Dec 2020 10:27:24 +0100 > From: "Peter J. Philipp" <p...@centroid.eu> > > On Mon, Dec 14, 2020 at 08:58:36AM +0100, Peter J. Philipp wrote: > > I guess I can do this though if you think it's the better way it's > > the better way, the bootloader that came with macppc I had > > converted to load 64-bit ELF binaries back in 2018 and I was > > thinking of re-using it. I guess I can tie in translation > > routines and that would be the core of the work. > > Hi I just want to pass an idea by you, I wonder if you like it or not. > > As you know the powerpc64 (and octeon) archs have a BOOT kernel. Instead of > dealing with the OpenBSD/macppc ofwboot and converting it to boot 64-bit ELF > kernels (which I've already done) and do a FDT compilation (while still in > virtual memory mode), how would you feel if I strip down the ofwboot to just > boot /boot instead of /bsd and it boots a 32-bit BOOT kernel (from macppc) > with a special boot driver to jump to 64-bit mode before executing the > running 64-bit kernel. > > Then I could write general functions in the BOOT kernel to compile a > FDT tree. It may be easier to work with the kernel than with > ofwboot. I just don't know if a BOOT kernel can be cross compiled > in 64-bit mode native environment. It sorta has a large footprint > across architectures but could give freedoms back inside the BOOT. > > It could make dual-booting easier on a G5 while adding a (half) stage to > macppc64 (and perhaps eventually macppc arch?).
Doesn't really make sense. The BOOT kernel is there because POWER9 "firmware" doesn't provide a device access interface. That limitation doesn't exist with Open Firmware. Having a BOOT kernel adds a significant delay to the boot process, so if we can avoid it, we probably should.
