linux-kernel - Re: [patch] x32, fpu: fix DNA exception during check

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Message-ID: <BANLkTikekBSzT-fQGJEk-U5JEuTsGQsBvQ@mail.gmail.com>
Date:	Thu, 30 Jun 2011 20:42:09 -0700
From:	Linus Torvalds <torvalds@...ux-foundation.org>
To:	Suresh Siddha <suresh.b.siddha@...el.com>
Cc:	"H. Peter Anvin" <hpa@...or.com>, Ingo Molnar <mingo@...e.hu>,
	Thomas Gleixner <tglx@...utronix.de>,
	LKML <linux-kernel@...r.kernel.org>
Subject: Re: [patch] x32, fpu: fix DNA exception during check_fpu()

On Thu, Jun 30, 2011 at 5:19 PM, Suresh Siddha
<suresh.b.siddha@...el.com> wrote:
>
> Before check_fpu() is called, we have cr0.TS bit set and hence the floating
> point code to check the FDIV bug was generating a DNA exception.
>
> Use kernel_fpu_begin()/kernel_fpu_end() around the floating point
> code to avoid this unnecessary device not available exception during
> boot.

Looks sane to me. I didn't think we were supposed to set the TS bit
this early, but if we do, Ack.

                 Linus
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