OpenBIOS SVN r416 breaks coreboot-v3

[Mark Cave-Ayland]

Hi everyone,

Whilst playing around with openbios to try and understand how it works 
on different platforms, I found that using coreboot-v3 with openbios SVN 
causes openbios to panic on boot under qemu SVN. The trace can be found 
here:

http://pastebin.siriusit.co.uk/coreboot-v3-panic.txt

With the help of some people on the coreboot mailing list, I've 
performed an SVN bisection and found that the panic starts appearing at 
r416 in openbios SVN for which the commit message can be found here:

http://lists.openbios.org/pipermail/openbios/2009-January/003401.html

However, I can't find any reference to the rationale behind the commit. 
Can anyone explain further explain whether is commit is correct or not? 
It would be really helpful if you could CC replies to the coreboot 
mailing list to help resolve this - the original thread can be found here:

http://www.coreboot.org/pipermail/coreboot/2009-January/044462.html

Many thanks,

Mark.

[Aurelien Jarno]

Mark Cave-Ayland a écrit :
> Hi everyone,
>
> Whilst playing around with openbios to try and understand how it works 
> on different platforms, I found that using coreboot-v3 with openbios SVN 
> causes openbios to panic on boot under qemu SVN. The trace can be found 
> here:
>
> http://pastebin.siriusit.co.uk/coreboot-v3-panic.txt
>
> With the help of some people on the coreboot mailing list, I've 
> performed an SVN bisection and found that the panic starts appearing at 
> r416 in openbios SVN for which the commit message can be found here:
>
> http://lists.openbios.org/pipermail/openbios/2009-January/003401.html
>
> However, I can't find any reference to the rationale behind the commit. 
> Can anyone explain further explain whether is commit is correct or not?

The rationale is available here:
http://lists.openbios.org/pipermail/openbios/2009-January/003391.html

This commit fixes two different problems encountered on SPARC64 and
PowerPC. First of all it makes sure that no PCI device get allocated
port 0, which doesn't exists.

Secondly it fixes problems with non-PCI devices that are using I/O ports
at fixed location. This includes the video card, i8259, rtc, serial
port, hard-disk controller, etc. Without this patch, the PCI cards are
getting allocated the I/O ports of those devices, thus causing crashes.

I wonder why it causes problem on x86. What is the initial value of
arch->io_base? I am unable to find that looking at the code.

[Mark Cave-Ayland]

Aurelien Jarno wrote:
> The rationale is available here:
> http://lists.openbios.org/pipermail/openbios/2009-January/003391.html

Thanks for link - I must have missed that whilst scanning the archives :)
> This commit fixes two different problems encountered on SPARC64 and
> PowerPC. First of all it makes sure that no PCI device get allocated
> port 0, which doesn't exists.
>
> Secondly it fixes problems with non-PCI devices that are using I/O ports
> at fixed location. This includes the video card, i8259, rtc, serial
> port, hard-disk controller, etc. Without this patch, the PCI cards are
> getting allocated the I/O ports of those devices, thus causing crashes.
>
> I wonder why it causes problem on x86. What is the initial value of
> arch->io_base? I am unable to find that looking at the code.

Well, I just added the following diff to my OpenBIOS build (latest SVN):

Index: drivers/pci.c
===================================================================
--- drivers/pci.c       (revision 428)
+++ drivers/pci.c       (working copy)
@@ -762,6 +762,9 @@
         mem_base = arch->mem_base;
          /* I/O ports under 0x400 are used by devices mapped at fixed
             location. */
+
+       printk("### io_base: %x\n", arch->io_base);
+
          io_base = arch->io_base + 0x400;
         path = strdup("");
         for (bus = 0; bus<0x100; bus++) {

...and in my output I got this:

### io_base: 0

Hmmm. I guess that explains why it is crashing.

ATB,

Mark.

[Blue Swirl]

On 1/28/09, Aurelien Jarno  wrote:
> Mark Cave-Ayland a écrit :
> > Hi everyone,
> >
> > Whilst playing around with openbios to try and understand how it works
> > on different platforms, I found that using coreboot-v3 with openbios SVN
> > causes openbios to panic on boot under qemu SVN. The trace can be found
> > here:
> >
> > http://pastebin.siriusit.co.uk/coreboot-v3-panic.txt
> >
> > With the help of some people on the coreboot mailing list, I've
> > performed an SVN bisection and found that the panic starts appearing at
> > r416 in openbios SVN for which the commit message can be found here:
> >
> > http://lists.openbios.org/pipermail/openbios/2009-January/003401.html
> >
> > However, I can't find any reference to the rationale behind the commit.
> > Can anyone explain further explain whether is commit is correct or not?
>
> The rationale is available here:
>  http://lists.openbios.org/pipermail/openbios/2009-January/003391.html
>
> This commit fixes two different problems encountered on SPARC64 and
>  PowerPC. First of all it makes sure that no PCI device get allocated
>  port 0, which doesn't exists.
>
> Secondly it fixes problems with non-PCI devices that are using I/O ports
>  at fixed location. This includes the video card, i8259, rtc, serial
>  port, hard-disk controller, etc. Without this patch, the PCI cards are
>  getting allocated the I/O ports of those devices, thus causing crashes.
>
> I wonder why it causes problem on x86. What is the initial value of
>  arch->io_base? I am unable to find that looking at the code.

I think "arch" (a bit unfortunate name choice for grepping) does not
get initialized at all for x86.