Re: [OpenBIOS] sparc64's get_physical_address_code should not fault on TTE's with V=0

[Jakub Jermar]

Blue Swirl wrote:
> On 1/12/09, Jakub Jermar  wrote:
> > Hi,
> >
> > when I make the following change to helper.c, get_physical_address_code:
> >    // ctx match, vaddr match?
> >    // ctx match, vaddr match, valid?
> >   if (env->dmmuregs[1] == (env->itlb_tag[i] & 0x1fff) &&
> >        (address & mask) == (env->itlb_tag[i] & ~0x1fffULL)) {
> >        // valid, access ok?
> >        if ((env->itlb_tte[i] & 0x8000000000000000ULL) == 0 ||
> >            ((env->itlb_tte[i] & 0x4) && is_user)) {
> >        (address & mask) == (env->itlb_tag[i] & ~0x1fffULL) &&
> >        env->itlb_tte[i] & 0x8000000000000000ULL) {
> >        // access ok?
> >        if ((env->itlb_tte[i] & 0x4) && is_user) {
> >
> > HelenOS gets a little bit further than without this change and seems
> >  to panic more or less gracefully later.
> >
> > In short, non-valid entries should be skipped by the loop in
> >  get_physical_address_code instead of causing TFAULT, because
> >  the ITLB can contain a valid entry for the same address. The
> >  same is true for DTLB.
> >
> > Can you confirm this?
>
> Yes, this looks correct. I'll apply a fix.

Thanks!

With this fix in place, HelenOS most of the time panics on:

Kernel panic: Cannot find property 'screen'.

I.e. it searches property 'screen' in /aliases and doesn't
find any. If it is not there already, could you please add
it (together with keyboard) to openbios?

Thanks,
Jakub