From owner-freebsd-bugs@FreeBSD.ORG Thu Mar 30 18:30:22 2006 Return-Path: X-Original-To: freebsd-bugs@hub.freebsd.org Delivered-To: freebsd-bugs@hub.freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id C406916A401 for ; Thu, 30 Mar 2006 18:30:22 +0000 (UTC) (envelope-from gnats@FreeBSD.org) Received: from freefall.freebsd.org (freefall.freebsd.org [216.136.204.21]) by mx1.FreeBSD.org (Postfix) with ESMTP id 7813043D45 for ; Thu, 30 Mar 2006 18:30:22 +0000 (GMT) (envelope-from gnats@FreeBSD.org) Received: from freefall.freebsd.org (gnats@localhost [127.0.0.1]) by freefall.freebsd.org (8.13.4/8.13.4) with ESMTP id k2UIUMZU081784 for ; Thu, 30 Mar 2006 18:30:22 GMT (envelope-from gnats@freefall.freebsd.org) Received: (from gnats@localhost) by freefall.freebsd.org (8.13.4/8.13.4/Submit) id k2UIUMVa081782; Thu, 30 Mar 2006 18:30:22 GMT (envelope-from gnats) Date: Thu, 30 Mar 2006 18:30:22 GMT Message-Id: <200603301830.k2UIUMVa081782@freefall.freebsd.org> To: freebsd-bugs@FreeBSD.org From: Nate Lawson Cc: Subject: Re: kern/94939: [acpi] [patch] reboot(8) fails on IBM / Intel blades X-BeenThere: freebsd-bugs@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list Reply-To: Nate Lawson List-Id: Bug reports List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 30 Mar 2006 18:30:22 -0000 The following reply was made to PR kern/94939; it has been noted by GNATS. From: Nate Lawson To: John Baldwin Cc: "Devon H. O'Dell" , bug-followup@freebsd.org Subject: Re: kern/94939: [acpi] [patch] reboot(8) fails on IBM / Intel blades Date: Thu, 30 Mar 2006 10:23:42 -0800 John Baldwin wrote: > On Tuesday 28 March 2006 02:22 pm, Devon H. O'Dell wrote: >> On Tue, Mar 28, 2006 at 11:08:02AM -0800, Nate Lawson wrote: >>> The system must reset immediately following the write to this register. >>> OSPM assumes that the processor will not execute beyond the write >>> instruction. OSPM should execute spin loops on the CPUs in the system >>> following a write to this register. >> My interpretation of this is ``don't do anything else after >> the write to the register, because you can't expect to do >> it.'' Since they say that the system ``must reset immediately >> following the write'', it seems that this is implemented in >> hardware, and we can't assume that we will be able to do >> anything afterwards, anyway. >> >>> So I'm ok with the patch being committed if no other tasks need to >>> happen after this shutdown handler is called. Also, all APs should be >>> stopped before this happens and it should only occur once on the BSP. >> I was curious if anything happens after this handler is >> called -- if there is, we definitely need to move it back >> to later in the process. Again, I put the code here because it >> looked to me like the procedure already assumed nothing else >> is happening, but it sounds like there are other procedures >> that are in the call queue after this one. > > It really should be much later I think: in cpu_reset_real() as that > is the only place that you know that the APs are stopped. I'm not near a BSD box today. Is there a simple, MI way of hooking there that doesn't require ACPI compiled into the kernel? If it's a simple matter of moving it to a different shutdown handler or adding a way for acpi to conditionally override cpu_reset_real, that's ok with me. I don't want acpi being partially merged into the main kernel. -- Nate