Re: MPTable can not be high-memory on Linux

From: Ingo Molnar
Date: Mon Feb 23 2009 - 01:43:13 EST



* Yinghai Lu <yinghai@xxxxxxxxxx> wrote:

> Ingo Molnar wrote:
> > * Kevin O'Connor <kevin@xxxxxxxxxxxx> wrote:
> >
> >> On Sun, Feb 22, 2009 at 01:33:35PM -0800, Yinghai Lu wrote:
> >> [...]
> >>>>>> BIOS-e820: 0000000000090000 - 0000000000100000 (reserved)
> >>>>>> BIOS-e820: 0000000000100000 - 000000003f7f0000 (usable)
> >>>>>> BIOS-e820: 000000003f7f0000 - 0000000040000000 (reserved)
> >> [...]
> >>>>>> found SMP MP-table at [c00f9fc0] 000f9fc0
> >> [...]
> >>> that should work for a long time.
> >>>
> >>> 0xf9fc0 < 1M is quite < max_low_pfn, so wonder why bootmem could panic.
> >> On this machine the mptable "floating" structure is at
> >> 0xf9fc0. It points to the rest of the table which is in the
> >> 0x3f7f0000 area.
> >>
> >> Note, that this is on a Coreboot+SeaBIOS machine - so we can
> >> change the bios. However, the mptable spec does allow for
> >> part of the table to be high memory.
> >
> > yes, and i'd prefer if it worked fine even if it's that high.
> >
>
> please check
>
> [PATCH] x86: check physptr with max_low_pfn on 32bit

Applied to tip:x86/apic, thanks Yinghai!

This will show up in v2.6.30. I suspect Coreboot will be changed
anyway (older Linux kernels may crash), but it's worth having
this bug fixed nevertheless.

Ingo
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