Re: [x86] do_arch_prctl - bug?

[Arjan van de Ven]

On Tue, 18 Nov 2008 15:33:32 +0100
Eric Lacombe <goretux@xxxxxxxxx> wrote:

> Hello,
> 
> I would like to know why the ARCH_SET_GS action of sys_arch_prctl,
> write the MSR MSR_KERNEL_GS_BASE and not the MSR MSR_GS_BASE when the
> variable "doit" equals 1? Is that a bug?
> 

I don't think it is.
The trick is that we use "swapgs" on entering/leaving the kernel, and
that will "swap" gs with the MSR, so when we return to userspace, GS
gets loaded from the MSR_KERNEL_GS_BASE ...


-- 
Arjan van de Ven 	Intel Open Source Technology Centre
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