Date: Thu, 2 Dec 2010 05:09:42 +0800 (SGT) From: Darmawan Salihun <darmawan_salihun@yahoo.com> To: freebsd-hackers@freebsd.org Subject: Re: How to debug BTX loader? Message-ID: <948728.57388.qm@web76807.mail.sg1.yahoo.com>
next in thread | raw e-mail | index | archive | help
Hi John,
--- On Tue, 11/30/10, John Baldwin <jhb@freebsd.org> wrote:
> From: John Baldwin <jhb@freebsd.org>
> Subject: Re: How to debug BTX loader?
> To: freebsd-hackers@freebsd.org
> Cc: "Darmawan Salihun" <darmawan_salihun@yahoo.com>
> Date: Tuesday, November 30, 2010, 9:38 AM
> On Monday, November 29, 2010 1:01:27
> pm Darmawan Salihun wrote:
> > Hi guys,
> >
> > I'm currently working on a BIOS for a custom Single
> Board Computer (SBC).
> > I have the required BIOS source code and tools at
> hand.
> > However, the boot process always stuck in the BTX
> loader
> > (the infamous "ACPI autoload failed") when I booted
> out of USB stick
> > (with the FreeBSD 8.1 USB stick image).
> >
> > I could get the system to boot into FreeBSD 8.1
> > (by keeping the CDROM tray open and close it when the
> board looks for
> > boot device, otherwise BTX will reboot instantly).
>
> Are you getting an actual BTX error message or a
> freeze? BTX is just a
> minikernel written all in assembly. It doesn't handle
> loading the kernel,
> etc. All that work is done by the /boot/loader
> program (which is written in
> C). You can find all the source to the boot code in
> src/sys/boot. The BTX
> kernel is in src/sys/boot/i386/btx/btx/.
>
> However, to debug this further we would need more info such
> as what exactly
> you are seeing (a hang, a BTX fault with a register dump,
> etc.).
One of the BTX fault shows the register dump in the attachment.
I hope this could help. Anyway, If I were to try to interpret
such register dump, where should I start? I understand x86/x86_64
assembly pretty much, but I'm not quite well versed with the
FreeBSD code using it.
Thanks,
Darmawan
>
> --
> John Baldwin
>
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?948728.57388.qm>