Re: [OpenBIOS] Booting SunOS from OpenBIOS

[Mark Cave-Ayland]

On 03/04/13 11:14, Artyom Tarasenko wrote:
> It seems to be an unrelated problem, double allocation of the page 0
> is still a double allocation.
>
> OTOH maybe the hint address 0 is an explicit invitation to get a next
> free chunk?

Very interesting. That could actually be right for two reasons:

1. 0x1000 is a multiple of page size

2. If you're not checking the return result, then what is the sense in 
requesting the same allocation (va = 0) twice?

So yes, I'd definitely try adding some test code to check if va == 0, 
and if so, set align = size before calling ofmem_claim_virt().

ATB,

Mark.

Booting SunOS from OpenBIOS

[Mark Cave-Ayland]

On 03/04/13 13:14, Mark Cave-Ayland wrote:
> Very interesting. That could actually be right for two reasons:
>
> 0x1000 is a multiple of page size
>
> If you're not checking the return result, then what is the sense in
>
> requesting the same allocation (va = 0) twice?
>
> So yes, I'd definitely try adding some test code to check if va == 0,
> and if so, set align = size before calling ofmem_claim_virt().

Trivial patch attached - a quick test shows that it still boots my 
Solaris 8 CD here.

ATB,

Mark.

Booting SunOS from OpenBIOS

[Artyom Tarasenko]

On Wed, Apr 3, 2013 at 2:34 PM, Mark Cave-Ayland
 wrote:
> On 03/04/13 13:14, Mark Cave-Ayland wrote:
> > Very interesting. That could actually be right for two reasons:
> >
> > 0x1000 is a multiple of page size
> >
> > If you're not checking the return result, then what is the sense in
> >
> > requesting the same allocation (va = 0) twice?
> >
> > So yes, I'd definitely try adding some test code to check if va == 0,
> > and if so, set align = size before calling ofmem_claim_virt().
>
> Trivial patch attached - a quick test shows that it still boots my Solaris 8
> CD here.

SunOS crashes at the same place as with your previous patch. (Which is
probably a good sign).

There is one interesting thing when I try to boot kadb:
OFMEM: ofmem_claim phys=ffffffffffffffff size=00001000 align=00001000
OFMEM: ofmem_claim_virt virt=00000000 size=00001000 align=00001000
OFMEM: ofmem_map_page_range ffc66000 -> 006f7a000 00001000 mode 000000bc
...
OFMEM: ofmem_claim phys=ffffffffffffffff size=00002000 align=00002000
OFMEM: ofmem_claim_virt virt=ffc65000 size=00002000 align=00000000
OFMEM: Non-free virtual memory claimed!
(and here it goes astray)

Does IEEE-1275 say something about this case?

linux/sparc and solaris/sparc under qemu blog:
http://tyom.blogspot.com/search/label/qemu