From mboxrd@z Thu Jan  1 00:00:00 1970
From: Florian Weimer <fweimer-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
Subject: Re: [RFC PATCH] getcpu_cache system call: caching current CPU number
 (x86)
Date: Mon, 20 Jul 2015 10:35:40 +0200
Message-ID: <55ACB2DC.5010503@redhat.com>
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Cc: Linus Torvalds <torvalds-de/tnXTf+JLsfHDXvbKv3WD2FQJk+8+b@public.gmane.org>, Mathieu Desnoyers <mathieu.desnoyers-vg+e7yoeK/dWk0Htik3J/w@public.gmane.org>, Ben Maurer <bmaurer-b10kYP2dOMg@public.gmane.org>, Paul Turner <pjt-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>, Andrew Hunter <ahh-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>, Peter Zijlstra <peterz-wEGCiKHe2LqWVfeAwA7xHQ@public.gmane.org>, Ingo Molnar <mingo-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>, rostedt <rostedt-nx8X9YLhiw1AfugRpC6u6w@public.gmane.org>, "Paul E. McKenney" <paulmck-23VcF4HTsmIX0ybBhKVfKdBPR1lH4CV8@public.gmane.org>, Josh Triplett <josh-iaAMLnmF4UmaiuxdJuQwMA@public.gmane.org>, Lai Jiangshan <laijs-BthXqXjhjHXQFUHtdCDX3A@public.gmane.org>, Andrew Morton <akpm-de/tnXTf+JLsfHDXvbKv3WD2FQJk+8+b@public.gmane.org>, linux-api <linux-api-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>, libc-alpha <libc-alpha-9JcytcrH/bA+uJoB2kUjGw@public.gmane.org>
List-Id: linux-api@vger.kernel.org

On 07/18/2015 01:33 AM, Andy Lutomirski wrote:

> I think the API should be "set gsbase to x + y*(cpu number)".  On
> x86_64, userspace just allocates a big swath of virtual space and
> populates it as needed.

This will break WINE and similar applications which use %gs today.

-- 
Florian Weimer / Red Hat Product Security