HEAD panic with ofw_pcibus.c 1.21 on Blade 100

[Marius Strobl]

On Mon, Sep 01, 2008 at 05:42:08PM +0100, Gavin Atkinson wrote:
> On Mon, 2008-09-01 at 18:18 +0200, Marius Strobl wrote:
> > On Mon, Sep 01, 2008 at 03:20:27PM +0100, Gavin Atkinson wrote:
> > > Hi all,
> > > 
> > > My Blade 100 now panics on boot with HEAD, and I've tracked it down to
> > > sys/sparc64/pci/ofw_pcibus.c 1.21 (SVN r182108) by marius at .
> 
> > The most likely reason for this is a buggy driver. In this
> > case the culprit appears to be the ISA front-end of ahc(4),
> > which assumes that it can do bus space reads and writes at
> > addresses that may in fact be assigned to a non-ahc(4)-
> > compatible device or none at all. While writing something
> > at an address that may no belong to the expected device
> > probably is a bad idea in generally, reading to and writing
> > from unassigned addresses may also trigger exceptions on
> > sparc64. I'm unsure how to really fix ahc(4) regarding this,
> > I think it should be okay though to only do it on i386 where
> > the address range in question probably is reserved for such
> > purposes (and which also is the only architecture FreeBSD
> > currently runs on where a machine might have an ISA-slot
> > and thus can use that front-end at all).
> > Justin, do you approve the below patch?
> > 
> > Marius
> > 
> > Index: ahc_isa.c
> > ===================================================================
> > --- ahc_isa.c	(revision 182474)
> > +++ ahc_isa.c	(working copy)
> > @@ -82,6 +82,12 @@ ahc_isa_identify(driver_t *driver, device_t parent
> >  	int slot;
> >  	int max_slot;
> >  
> > +#if !defined(__i386__)
> > +	/*
> > +	 * Don't assume we can get away with the blind bus space
> > +	 * reads and writes which ahc_isa_find_device() does.
> > +	 */
> > +#endif
> >  	max_slot = 14;
> >  	for (slot = 0; slot <= max_slot; slot++) {
> >  		struct aic7770_identity *entry;
> 
> This patch (with the addition of a "return;" inside the #ifdef which I'm
> assuming was forgotten!) gets me booting again with stock ofw_pcibus.c.

Oops, the "return;" was missing of course.

Marius