Re: [PATCH] [CAN-2004-1144] Fix int 0x80 hole in 2.4 x86-64 linux kernels

From: Willy Tarreau
Date: Wed Dec 22 2004 - 13:49:09 EST


On Wed, Dec 22, 2004 at 07:23:13PM +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.

Ok, thanks for this quick precision, it wasn't obvious at first glance.

> See the x86-64 architecture manuals for more details.

Oh, I did a long time ago, when the athlon64 was only an emulator which ran
under linux, but I forgot all the details since then.

Thanks,
Willy

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