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Date: Wed, 4 Mar 2015 21:39:58 +0100
From: Ingo Molnar <mingo@kernel.org>
To: Andy Lutomirski <luto@amacapital.net>
Cc: X86 ML <x86@kernel.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        Borislav Petkov <bp@alien8.de>, Oleg Nesterov <oleg@redhat.com>,
        Denys Vlasenko <dvlasenk@redhat.com>,
        Linus Torvalds <torvalds@linux-foundation.org>
Subject: Re: [RFC 1/3] x86: Add this_cpu_sp0() to read sp0 for the current cpu
Message-ID: <20150304203958.GA7247@gmail.com>
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* Andy Lutomirski <luto@amacapital.net> wrote:

> On Wed, Mar 4, 2015 at 12:02 AM, Ingo Molnar <mingo@kernel.org> wrote:
> >
> > * Andy Lutomirski <luto@amacapital.net> 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.

Thanks,

	Ingo