From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752509AbaGLShw (ORCPT ); Sat, 12 Jul 2014 14:37:52 -0400 Received: from one.firstfloor.org ([193.170.194.197]:53817 "EHLO one.firstfloor.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751862AbaGLShu (ORCPT ); Sat, 12 Jul 2014 14:37:50 -0400 Date: Sat, 12 Jul 2014 20:37:48 +0200 From: Andi Kleen To: Andy Lutomirski Cc: Linus Torvalds , "linux-kernel@vger.kernel.org" , Andi Kleen , "H. Peter Anvin" , Al Viro , the arch/x86 maintainers Subject: Re: [PATCH 2/2] x86_64,signal: Remove 'fs' and 'gs' from sigcontext Message-ID: <20140712183748.GW18735@two.firstfloor.org> References: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.20 (2009-06-14) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org > This seems like it's asking for trouble. I think wxe'd have to > separately save the selectors and the base registers to avoid breaking > something, especially once wrgsbase, etc are enabled. I agree, it would likely break existing code. > Linus, for context, the other patch in this series saves and restores > SS. > Without that, 64-bit sigreturn to a nondefault stack segment is > basically impossible. Why would you ever want to do that? -Andi