Re: Boot failure in 2.5.31 BK with new TLS patch

Pavel Machek (pavel@suse.cz)
Fri, 2 Nov 2001 08:20:21 +0000


Hi!

> > The boot problem only happens with my quad pentium cards, the dyad
> > pentium and 486 are fine. Originally, a voyager system with quad cards
> > just wouldn't boot (this was in the 2.2.x days). Eventually, by trial
> > and error and long debug of the boot process I discovered it would boot
> > if the GDT was 8 bytes aligned (actually, the manuals say it should be
> > 16 byte aligned, so perhaps we should also add this to the Linux
> > setup.S?). [...]
>
> indeed it's not aligned:
>
> c010025c T cpu_gdt_descr
>
> could you align it by adding this line replacing the ALIGN line that
> preceeds the cpu_gdt_descr definition in head.S:
>
> .align 32
>
> we want to align the GDT to 32 bytes anyway, we have optimized it for
> cache layout, and didnt realize that it wasnt aligned to begin with ...

You might want to .align L1_CACHE_SIZE (or something), IIRC P4s have bigger
cachelines than 32.
Pave

-- 
Philips Velo 1: 1"x4"x8", 300gram, 60, 12MB, 40bogomips, linux, mutt,
details at http://atrey.karlin.mff.cuni.cz/~pavel/velo/index.html.

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