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From: Andrew Lutomirski <amluto@gmail.com>
Date: Mon, 21 Apr 2014 18:53:36 -0700
Message-ID: <CAObL_7HTDvN2zu2_CDnVR_ztZ-b7PfLYz0csuVX-ShQ7EHGEjg@mail.gmail.com>
Subject: Re: [PATCH] x86-64: espfix for 64-bit mode *PROTOTYPE*
To: "H. Peter Anvin" <hpa@zytor.com>
Cc: "H. Peter Anvin" <hpa@linux.intel.com>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        Linus Torvalds <torvalds@linux-foundation.org>,
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        Alexander van Heukelum <heukelum@fastmail.fm>,
        Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>,
        Boris Ostrovsky <boris.ostrovsky@oracle.com>,
        Borislav Petkov <bp@alien8.de>,
        Arjan van de Ven <arjan.van.de.ven@intel.com>,
        Brian Gerst <brgerst@gmail.com>,
        Alexandre Julliard <julliard@winehq.com>,
        Andi Kleen <andi@firstfloor.org>, Thomas Gleixner <tglx@linutronix.de>
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On Mon, Apr 21, 2014 at 6:47 PM, H. Peter Anvin <hpa@zytor.com> wrote:
> Race condition (although with x86 being globally ordered, it probably can't actually happen.) The bitmask is probably the way to go.

Does the race matter?  In the worst case you take the lock
unnecessarily.  But yes, the bitmask is easy.

--Andy
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