Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754517Ab3H2OTI (ORCPT ); Thu, 29 Aug 2013 10:19:08 -0400 Received: from iolanthe.rowland.org ([192.131.102.54]:40897 "HELO iolanthe.rowland.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with SMTP id S1753995Ab3H2OTE (ORCPT ); Thu, 29 Aug 2013 10:19:04 -0400 Date: Thu, 29 Aug 2013 10:19:03 -0400 (EDT) From: Alan Stern X-X-Sender: stern@iolanthe.rowland.org To: "H. Peter Anvin" cc: "Paul E. McKenney" , Russell King , Ingo Molnar , David Howells , Ming Lei , USB list , Kernel development list Subject: Re: Memory synchronization vs. interrupt handlers In-Reply-To: <521E5D58.5070708@zytor.com> Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 925 Lines: 28 On Wed, 28 Aug 2013, H. Peter Anvin wrote: > On 08/28/2013 12:16 PM, Alan Stern wrote: > > Russell, Peter, and Ingo: > > > > Can you folks enlighten us regarding this issue for some common > > architectures? > > > > On x86, IRET is a serializing instruction; it guarantees hard > serialization of absolutely everything. That answers half of the question. What about the other half? Does the CPU automatically serialize everything when it takes an interrupt? > I would expect architectures that have weak memory ordering to put > appropriate barriers in the IRQ entry/exit code. Then would it be acceptable to mention this in the memory-barriers.txt file? Alan Stern -- 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/