linux-kernel - Re: [PATCH] x86, 64-bit: Set data segments to null after switching to 64-bit mode

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Message-ID: <4B125E8A.7020306@klingt.org>
Date:	Sun, 29 Nov 2009 12:44:10 +0100
From:	Tim Blechmann <tim@...ngt.org>
To:	Brian Gerst <brgerst@...il.com>
CC:	Ingo Molnar <mingo@...e.hu>, x86@...nel.org,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH] x86, 64-bit: Set data segments to null after switching
 to 64-bit mode

On 11/25/2009 05:17 PM, Brian Gerst wrote:
> This prevents kernel threads from inheriting non-null segment selectors,
> and causing optimizations in __switch_to() to be ineffective.
> 
> Signed-off-by: Brian Gerst <brgerst@...il.com>

with this patch, the branch hint is actually correct, giving 100%
correct predictions. so please revert my earlier patch (commit
a3a1de0c34de6f5f8332cd6151c46af7813c0fcb)

thnx, tim

-- 
tim@...ngt.org
http://tim.klingt.org

Desperation is the raw material of drastic change. Only those who can
leave behind everything they have ever believed in can hope to escape.
  William S. Burroughs

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