From: Andi Kleen <andi@firstfloor.org>
To: Colin King <colin.king@canonical.com>
Cc: Ingo Molnar <mingo@redhat.com>, "H. Peter Anvin" <hpa@zytor.com>,
Thomas Gleixner <tglx@linutronix.de>,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH] x86: Disable 4MB page tables for Atom, work around errata AAE44
Date: Mon, 12 Apr 2010 10:02:19 +0200 [thread overview]
Message-ID: <87633xayk4.fsf@basil.nowhere.org> (raw)
In-Reply-To: <1269271251-19775-1-git-send-email-colin.king@canonical.com> (Colin King's message of "Mon, 22 Mar 2010 15:20:51 +0000")
Colin King <colin.king@canonical.com> 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@linux.intel.com -- Speaking for myself only.
next prev parent reply other threads:[~2010-04-12 8:02 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-03-22 15:20 [PATCH] x86: Disable 4MB page tables for Atom, work around errata AAE44 Colin King
2010-03-31 22:35 ` Jeremy Fitzhardinge
2010-04-12 8:02 ` Andi Kleen [this message]
2010-04-12 14:37 ` H. Peter Anvin
2010-05-01 21:37 ` Yuhong Bao
2010-04-23 23:52 ` [tip:x86/urgent] x86: Disable large pages on CPUs with Atom erratum AAE44 tip-bot for H. Peter Anvin
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