From: Rene Herman <rene.herman@keyaccess.nl>
To: Andreas Herrmann <andreas.herrmann3@amd.com>
Cc: Thomas Gleixner <tglx@linutronix.de>, Ingo Molnar <mingo@elte.hu>,
"H. Peter Anvin" <hpa@zytor.com>,
linux-kernel@vger.kernel.org,
Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>,
Suresh B Siddha <suresh.b.siddha@intel.com>
Subject: Re: [PATCH 2/5] x86: PAT: fix ambiguous paranoia check in pat_init()
Date: Wed, 11 Jun 2008 00:55:23 +0200 [thread overview]
Message-ID: <484F065B.2050002@keyaccess.nl> (raw)
In-Reply-To: <20080610140518.GF5024@alberich.amd.com>
On 10-06-08 16:05, Andreas Herrmann wrote:
> Starting with commit 8d4a4300854f3971502e81dacd930704cb88f606 (x86:
> cleanup PAT cpu validation) the PAT CPU feature flag is not cleared
> anymore. Now the error message
>
> "PAT enabled, but CPU feature cleared"
>
> in pat_init() is misleading.
No, it's correct. This is to be read as "The PAT feature is enabled in
the kernel but the CPU claims to not have PAT". The message is not a
leftover from the old flag-clearing setup or anything; it was introduced
in the patch that disabled that.
> Furthermore the current code does not check for existence of the PAT
> CPU feature flag if a CPU is whitelisted in validate_pat_support.
Which is okay-ish, or at least by design it seems. The paranoia check in
pat.c will catch this case.
The current setup is okay really. The only thing it still wants is a
commandline whitelist switch but that needs a somewhat different setup
as validate_pat_support() is too early for __setup() or early_param().
Rene.
next prev parent reply other threads:[~2008-06-10 22:55 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-06-10 14:05 [PATCH 2/5] x86: PAT: fix ambiguous paranoia check in pat_init() Andreas Herrmann
2008-06-10 22:55 ` Rene Herman [this message]
2008-06-10 23:33 ` H. Peter Anvin
2008-06-11 9:47 ` Andreas Herrmann
2008-06-11 15:05 ` [PATCH] x86: enable PAT on (almost) all CPUs that advertise it Andreas Herrmann
2008-06-11 16:44 ` H. Peter Anvin
2008-06-11 17:35 ` [PATCH 2/5] x86: PAT: fix ambiguous paranoia check in pat_init() H. Peter Anvin
2008-06-11 9:41 ` Andreas Herrmann
2008-06-11 12:58 ` Rene Herman
2008-06-11 16:12 ` Andreas Herrmann
2008-06-12 4:32 ` Rene Herman
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