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Date: Wed, 22 Dec 2004 19:23:13 +0100
From: Andi Kleen <ak@suse.de>
To: Willy Tarreau <willy@w.ods.org>
Cc: Andi Kleen <ak@suse.de>, discuss@x86-64.org, linux-kernel@vger.kernel.org,
       marcelo.tosatti@cyclades.com, vandrove@vc.cvut.cz
Subject: Re: [PATCH] [CAN-2004-1144] Fix int 0x80 hole in 2.4 x86-64 linux kernels
Message-ID: <20041222182313.GB3363@wotan.suse.de>
References: <20041222175818.GA3363@wotan.suse.de> <20041222182048.GM17946@alpha.home.local>
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On Wed, Dec 22, 2004 at 07:20:48PM +0100, Willy Tarreau wrote:
> Hi Andi,
> 
> On Wed, Dec 22, 2004 at 06:58:18PM +0100, Andi Kleen wrote:
> (...)
> >  	sti
> > +	movl %eax,%eax	
> >  	pushq %rax
> 
> Although I don't know about x86_64 assembly, I know x86 and I wonder
> how this patch would do anything. I would personnaly have written something
> more like :

An 32bit write in long mode clears the upper 32bits of the register.
See the x86-64 architecture manuals for more details.

-Andi