Re: [RFC] - Mapping ACPI tables as CACHED

[Matthew Garrett]

On Fri, Jul 23, 2010 at 09:14:50PM -0300, Henrique de Moraes Holschuh wrote:
> Well, as it was raised in this thread, ACPI tables are likely to be near RAM
> regions used for IPC with the firmware or SMBIOS, and we have no idea of the
> kind of crap that could happen if we enable caching on those areas.
> 
> OTOH, we *know* of systems that force us to copy the ACPI tables to regular
> RAM, otherwise, the utterly broken BIOS corrupts the ACPI tables after the
> kernel has loaded.
>
> Couldn't we simply always copy all tables to regular RAM and mark THAT as
> cacheable (since there will be no IPC regions in it)?  For the tables that
> are only used once, we can free the RAM later.

I think this is reasonable. There's an argument that we shouldn't cache 
operation regions that may be sitting next to the ACPI tables, but I 
can't see any problems being caused by copying the tables to RAM.

-- 
Matthew Garrett | mjg59@xxxxxxxxxxxxx
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/