Re: [RFC 1/3] x86: Add this_cpu_sp0() to read sp0 for the current cpu

[Ingo Molnar]

* Andy Lutomirski <luto@xxxxxxxxxxxxxx> wrote:

> On Wed, Mar 4, 2015 at 12:39 PM, Ingo Molnar <mingo@xxxxxxxxxx> wrote:
> >
> > * Andy Lutomirski <luto@xxxxxxxxxxxxxx> wrote:
> >
> >> On Wed, Mar 4, 2015 at 12:02 AM, Ingo Molnar <mingo@xxxxxxxxxx> wrote:
> >> >
> >> > * Andy Lutomirski <luto@xxxxxxxxxxxxxx> wrote:
> >> >
> >> >> We currently store references to the top of the kernel stack in
> >> >> multiple places: kernel_stack (with an offset) and
> >> >> init_tss.x86_tss.sp0 (no offset).  The latter is defined by hardware
> >> >> and is a clean canonical way to find the top of the stack.  Add an
> >> >
> >> > Btw., 'per_cpu(init_tss)' is a somewhat misleading name these days, as
> >> > there's nothing 'init' about it anymore - we load it during CPU init
> >> > and then manually maintain its contents. A better name would be
> >> > 'current_tss' - referring to both the current CPU and the current
> >> > task?
> >>
> >> Hmm.  That seems a little odd to me, since we never change the TSS
> >> pointer.  It's certainly better than init_tss, though.  I'll add a
> >> followup to rename it.
> >
> > Alternatively we could use 'cpu_tss': the CPU's current TSS.
> 
> I painted my bikeshed "singleton_tss", since cpu_tss seemed 
> redundant for something that's already per cpu.  If you prefer your 
> bikeshed color, let me know.

Yeah, name it *anything* but 'singleton'!!

/me gets sick of design patterns ;-)

Thanks,

	Ingo
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