Re: [PATCH] x86: Disable 4MB page tables for Atom, work around errata AAE44

From: Andi Kleen
Date: Mon Apr 12 2010 - 04:02:32 EST


Colin King <colin.king@xxxxxxxxxxxxx> writes:
>
> +static void __init check_atom(void)
> +{
> +
> + /*
> + * Disable 4MB page tables to work around Intel errata AAE44 for
> + * Atom. We cannot guarantee stopping undefined processor behaviour
> + * when two pageing structure translations differ with respect to
> + * page frame sizes. Hence, for Atoms we disable the PSE.
> + */
> + if (boot_cpu_data.x86_model == 0x1c) {

Perhaps someone else pointed that out already, but you obviously
need to check for x86_vendor == X86_VENDOR_INTEL and x86_family == 6 too,
otherwise you'll get false positives.

Besides such workarounds are normally in arch/x86/kernel/cpu/intel.c.
bugs.c is really obsolete.

-Andi

--
ak@xxxxxxxxxxxxxxx -- Speaking for myself only.
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