Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S262492AbVDGRSk (ORCPT ); Thu, 7 Apr 2005 13:18:40 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S262502AbVDGRSk (ORCPT ); Thu, 7 Apr 2005 13:18:40 -0400 Received: from alog0304.analogic.com ([208.224.222.80]:47244 "EHLO chaos.analogic.com") by vger.kernel.org with ESMTP id S262492AbVDGRSg (ORCPT ); Thu, 7 Apr 2005 13:18:36 -0400 Date: Thu, 7 Apr 2005 13:17:28 -0400 (EDT) From: "Richard B. Johnson" Reply-To: linux-os@analogic.com To: Dave Jones cc: Linus Torvalds , Andrew Morton , Ingo Molnar , stsp@aknet.ru, linux-kernel@vger.kernel.org, VANDROVE@vc.cvut.cz Subject: Re: crash in entry.S restore_all, 2.6.12-rc2, x86, PAGEALLOC In-Reply-To: <20050407164734.GB19016@redhat.com> Message-ID: References: <20050405065544.GA21360@elte.hu> <4252E2C9.9040809@aknet.ru> <4252EA01.7000805@aknet.ru> <425403F6.409@aknet.ru> <20050407080004.GA27252@elte.hu> <20050407041006.4c9db8b2.akpm@osdl.org> <20050407164734.GB19016@redhat.com> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII; format=flowed Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1432 Lines: 41 On Thu, 7 Apr 2005, Dave Jones wrote: > On Thu, Apr 07, 2005 at 07:47:41AM -0700, Linus Torvalds wrote: > > > So the sysenter sequence might as well look like > > > > pushl $(__USER_DS) > > pushl %ebp > > sti > > pushfl > > .. > > > > which actually does three protected pushes thanks to the one-instruction > > "interrupt shadow" after an sti. > > Is this guaranteed on every x86 variant (or rather, every one > that has SEP). ? > > Dave The i486 book says that if the next instruction lets the IF flag remain enabled, then any interrupts pending occur after the next instruction. If the next instruction is CLI, no interrupts will occur. There is a note: "In case of an NM1, trap, or fault following ST1, the interrupt will be taken before executing the next sequential instruction in the code." The use of "NM1" and "ST1" is (sic). I don't know what NM1 is, it can't be NMI because, by definition NMI is not maskable so CLI and STI could not affect this pin. Cheers, Dick Johnson Penguin : Linux version 2.6.11 on an i686 machine (5537.79 BogoMips). Notice : All mail here is now cached for review by Dictator Bush. 98.36% of all statistics are fiction. - 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/