Re: [PATCH 03/35] x86/entry/32: Load task stack from x86_tss.sp1 in SYSENTER handler

[Andi Kleen]

On Wed, Apr 18, 2018 at 05:02:02PM -0700, Linus Torvalds wrote:
> On Wed, Apr 18, 2018 at 4:26 PM, Andi Kleen <ak@xxxxxxxxxxxxxxx> wrote:
> >
> > Seems like a hack. Why can't that be stored in a per cpu variable?
> 
> It *is* a percpu variable - the whole x86_tss structure is percpu.
> 
> I guess it could be a different (separate) percpu variable, but might
> as well use the space we already have allocated.

Would be better/cleaner to use a separate variable instead of reusing
x86 structures like this. Who knows what subtle side effects that
may have eventually.

It will be also easier to understand in the code.

-Andi