Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1031002AbbDWVqa (ORCPT ); Thu, 23 Apr 2015 17:46:30 -0400 Received: from mail.skyhub.de ([78.46.96.112]:37370 "EHLO mail.skyhub.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1030809AbbDWVq1 (ORCPT ); Thu, 23 Apr 2015 17:46:27 -0400 Date: Thu, 23 Apr 2015 23:46:16 +0200 From: Borislav Petkov To: "H. Peter Anvin" Cc: Denys Vlasenko , Andy Lutomirski , Linus Torvalds , Brian Gerst , Denys Vlasenko , Ingo Molnar , Steven Rostedt , Oleg Nesterov , Frederic Weisbecker , Alexei Starovoitov , Will Drewry , Kees Cook , the arch/x86 maintainers , Linux Kernel Mailing List Subject: Re: [PATCH] x86/asm/entry/32: Restore %ss before SYSRETL if necessary Message-ID: <20150423214616.GU28327@pd.tnic> References: <1429792491-5978-1-git-send-email-dvlasenk@redhat.com> <20150423211015.GS28327@pd.tnic> <55396617.4020303@zytor.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <55396617.4020303@zytor.com> User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 732 Lines: 25 On Thu, Apr 23, 2015 at 02:37:27PM -0700, H. Peter Anvin wrote: > Yes, the NULL SS is a special thing in 64-bit mode. I agree that > context-switching it is probably the way to go; it should be cheap > enough. We might even be able to conditionalize it on an X86_BUG_ > flag. Oh sure, I was thinking of an AMD-specific "call amd_fixup_ss" which gets NOPped out on Intel. We do those for breakfast :-) -- Regards/Gruss, Boris. ECO tip #101: Trim your mails when you reply. -- -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/