Re: FSGSBASE ABI considerations

From: Andy Lutomirski
Date: Mon Jul 31 2017 - 10:16:40 EST


On Mon, Jul 31, 2017 at 3:55 AM, Kirill A. Shutemov
<kirill@xxxxxxxxxxxxx> wrote:
> On Sun, Jul 30, 2017 at 08:05:43PM -0700, Andy Lutomirski wrote:
>> Hi all-
>>
>> Chang wants to get the FSGSBASE patches in. Here's a bit on a brain
>> dump on what I think the relevant considerations are and why I haven't
>> sent out my patches.
>
> I'm not sure if it would be relevant input for the descussion, but there's
> another issue with FSGSBASE vs LA57:
>
> http://lkml.kernel.org/r/9ddf602b-6c8b-8c1e-ab46-07ed12366593@xxxxxxxxxx

Clearly we should support FSGSBASE on Linux, have Paolo blacklist it
on LA57 machines, and get Java to start using it just to pressure
Intel to clean up this mess.

Sigh, the degree to which CPU engineers don't understand software is
sometimes mind-boggling.