From: "H. Peter Anvin" <hpa@zytor.com>
To: Simon Arlott <simon@fire.lp0.eu>
Cc: Claas Langbehn <claas@rootdir.de>,
LKML <linux-kernel@vger.kernel.org>,
Andrew Morton <akpm@linux-foundation.org>
Subject: Re: This kernel requires the following features not present on the CPU... (on a VIA C7 CPU)
Date: Thu, 17 May 2007 15:19:14 -0700 [thread overview]
Message-ID: <464CD4E2.6090402@zytor.com> (raw)
In-Reply-To: <464CD45A.6090902@simon.arlott.org.uk>
Simon Arlott wrote:
> On 17/05/07 21:15, H. Peter Anvin wrote:
>> Simon Arlott wrote:
>>> Is it automatic? I have CONFIG_X86_CMPXCHG=y without cx8 showing in
>>> cpuinfo, and it appears to work fine.
>>>
>>> Will your changes needlessly prevent the kernel running? Would I be
>>> right in thinking that the kernel is successfully using cmpxchg even
>>> though it's considered disabled? I realise people compile kernels for
>>> the wrong CPU but preventing them working when it's been chosen
>>> correctly seems wrong.
>>>
>>
>> CX8 isn't cmpxchg; it's cmpxchg8b.
>
> Ok, but I have CONFIG_X86_CMPXCHG64=y too.
>
OK then, then VIA just masks the CPUID bit as opposed to the
instruction. Point still holds.
-hpa
next prev parent reply other threads:[~2007-05-17 22:30 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-05-17 12:27 This kernel requires the following features not present on the CPU... (on a VIA C7 CPU) Claas Langbehn
2007-05-17 15:24 ` Alan Cox
2007-05-17 15:41 ` Claas Langbehn
2007-05-17 18:33 ` H. Peter Anvin
2007-05-18 11:17 ` Claas Langbehn
2007-05-17 20:12 ` Simon Arlott
2007-05-17 20:15 ` H. Peter Anvin
2007-05-17 22:16 ` Simon Arlott
2007-05-17 22:19 ` H. Peter Anvin [this message]
2007-05-18 6:24 ` Jan Engelhardt
2007-05-17 20:13 ` Simon Arlott
-- strict thread matches above, loose matches on Subject: below --
2007-05-20 1:30 Artur Kedzierski
2007-05-22 6:55 ` Claas Langbehn
2007-05-22 15:53 ` Christian Volkmann
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