Re: [Xen-devel] Does __KERNEL_DS serve a purpose?

[Andrew Cooper]

On 08/04/2016 01:24, Andy Lutomirski wrote:
> I can't see any reason that we need the __KERNEL_DS segment at all --
> I think that everything that uses __KERNEL_DS could use __USER_DS
> instead.  Am I missing anything?  This has been bugging me for a
> while.
>
> I mulled over this a bit when trying to understand the sysret_ss_attrs
> bug and then forgot about it.

Linux doesn't have a separate __KERNEL_SS.  For the plain data segments,
the dpl is not interesting.

However, %ss is also loaded with __KERNEL_DS, and %ss.dpl is somewhat
important.

~Andrew