How to debug BTX loader?
darmawan_salihun at yahoo.com
Thu Dec 2 19:12:07 UTC 2010
--- On Thu, 12/2/10, John Baldwin <jhb at freebsd.org> wrote:
> From: John Baldwin <jhb at freebsd.org>
> Subject: Re: How to debug BTX loader?
> To: freebsd-hackers at freebsd.org
> Cc: "Darmawan Salihun" <darmawan_salihun at yahoo.com>
> Date: Thursday, December 2, 2010, 8:58 AM
> On Wednesday, December 01, 2010
> 4:09:42 pm Darmawan Salihun wrote:
> > Hi John,
> > --- On Tue, 11/30/10, John Baldwin <jhb at freebsd.org>
> > > From: John Baldwin <jhb at freebsd.org>
> > > Subject: Re: How to debug BTX loader?
> > > To: freebsd-hackers at freebsd.org
> > > Cc: "Darmawan Salihun" <darmawan_salihun at 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
> > > 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
> > > out of USB stick
> > > > (with the FreeBSD 8.1 USB stick image).
> > > >
> > > > I could get the system to boot into FreeBSD
> > > > (by keeping the CDROM tray open and close it
> when the
> > > board looks for
> > > > boot device, otherwise BTX will reboot
> > >
> > > 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
> > > 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
> > I hope this could help. Anyway, If I were to try to
> > such register dump, where should I start? I understand
> > assembly pretty much, but I'm not quite well versed
> with the
> > FreeBSD code using it.
> Looks like the mailing list stripped the attachment.
> Can you post the
> attachment at a URL?
The BTX crash message is in the attachment.
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