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

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:	Wed, 4 Mar 2015 23:12:58 +0100
From:	Ingo Molnar <mingo@...nel.org>
To:	Andy Lutomirski <luto@...capital.net>
Cc:	X86 ML <x86@...nel.org>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	Borislav Petkov <bp@...en8.de>,
	Oleg Nesterov <oleg@...hat.com>,
	Denys Vlasenko <dvlasenk@...hat.com>,
	Linus Torvalds <torvalds@...ux-foundation.org>
Subject: Re: [RFC 1/3] x86: Add this_cpu_sp0() to read sp0 for the current cpu


* Andy Lutomirski <luto@...capital.net> wrote:

> On Wed, Mar 4, 2015 at 12:39 PM, Ingo Molnar <mingo@...nel.org> wrote:
> >
> > * Andy Lutomirski <luto@...capital.net> wrote:
> >
> >> On Wed, Mar 4, 2015 at 12:02 AM, Ingo Molnar <mingo@...nel.org> wrote:
> >> >
> >> > * Andy Lutomirski <luto@...capital.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.
> 
> 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
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/