Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753136AbaF0T3k (ORCPT ); Fri, 27 Jun 2014 15:29:40 -0400 Received: from mx1.redhat.com ([209.132.183.28]:32712 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750997AbaF0T3g (ORCPT ); Fri, 27 Jun 2014 15:29:36 -0400 Date: Fri, 27 Jun 2014 21:27:53 +0200 From: Oleg Nesterov To: Kees Cook Cc: Andy Lutomirski , LKML , "Michael Kerrisk (man-pages)" , Alexei Starovoitov , Andrew Morton , Daniel Borkmann , Will Drewry , Julien Tinnes , David Drysdale , Linux API , "x86@kernel.org" , "linux-arm-kernel@lists.infradead.org" , linux-mips@linux-mips.org, linux-arch , linux-security-module Subject: Re: [PATCH v8 5/9] seccomp: split mode set routines Message-ID: <20140627192753.GA30752@redhat.com> References: <20140625173245.GA17695@redhat.com> <20140625175136.GA18185@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.18 (2008-05-17) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 06/27, Kees Cook wrote: > > It looks like SMP ARM issues dsb for rmb, which seems a bit expensive. > http://infocenter.arm.com/help/index.jsp?topic=/com.arm.doc.dui0204g/CIHJFGFE.htm > > ... > > I really want to avoid adding anything to the secure_computing() > execution path. :( I must have missed something but I do not understand your concerns. __secure_computing() is not trivial, and we are going to execute the filters. Do you really think rmb() can add the noticeable difference? Not to mention that we can only get here if we take the slow syscall enter path due to TIF_SECCOMP... Oleg. -- 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/