From owner-freebsd-ppc@FreeBSD.ORG Wed May 7 15:22:27 2008 Return-Path: Delivered-To: freebsd-ppc@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id B25EC106566C; Wed, 7 May 2008 15:22:27 +0000 (UTC) (envelope-from nathanw@uchicago.edu) Received: from agogare.doit.wisc.edu (agogare.doit.wisc.edu [144.92.197.211]) by mx1.freebsd.org (Postfix) with ESMTP id 87F298FC31; Wed, 7 May 2008 15:22:27 +0000 (UTC) (envelope-from nathanw@uchicago.edu) MIME-version: 1.0 Content-transfer-encoding: 7BIT Content-type: text/plain; charset=ISO-8859-1; format=flowed Received: from avs-daemon.smtpauth2.wiscmail.wisc.edu by smtpauth2.wiscmail.wisc.edu (Sun Java(tm) System Messaging Server 6.3-5.02 (built Oct 12 2007; 32bit)) id <0K0I00J0081F9V00@smtpauth2.wiscmail.wisc.edu>; Wed, 07 May 2008 10:22:27 -0500 (CDT) Received: from trantor.tachypleus.net (adsl-76-204-93-14.dsl.mdsnwi.sbcglobal.net [76.204.93.14]) by smtpauth2.wiscmail.wisc.edu (Sun Java(tm) System Messaging Server 6.3-5.02 (built Oct 12 2007; 32bit)) with ESMTPSA id <0K0I00EW181DGT50@smtpauth2.wiscmail.wisc.edu>; Wed, 07 May 2008 10:22:25 -0500 (CDT) Date: Wed, 07 May 2008 10:22:45 -0500 From: Nathan Whitehorn In-reply-to: <4821C85A.7090605@freebsd.org> To: grehan@freebsd.org Message-id: <4821C945.5030008@uchicago.edu> X-Spam-Report: AuthenticatedSender=yes, SenderIP=76.204.93.14 X-Spam-PmxInfo: Server=avs-7, Version=5.4.1.325704, Antispam-Engine: 2.6.0.325393, Antispam-Data: 2008.5.7.80748, SenderIP=76.204.93.14 References: <4821C6AB.3080101@uchicago.edu> <4821C85A.7090605@freebsd.org> User-Agent: Thunderbird 2.0.0.12 (X11/20080322) Cc: freebsd-ppc@freebsd.org Subject: Re: UMA_MD_SMALL_ALLOC X-BeenThere: freebsd-ppc@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Porting FreeBSD to the PowerPC List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 07 May 2008 15:22:27 -0000 Peter Grehan wrote: > Hi Nathan, > >> In doing the G5 port, I have a problem with the UMA_MD_SMALL_ALLOC >> option. Because the G5 does not have BAT, this is broken. Even if we >> were to emulate it with pages, this is not a useful thing to have, >> since the point of the option would be defeated. But removing it would >> pessimize the G3/G4 port (the AIM code also panics late in boot >> without it, but that is a separate issue). >> >> There doesn't seem to be a way to twiddle it at runtime, which is a >> major problem if we want to have a single kernel running on all OEA >> machines. So I'm not sure what to do. Thoughts? > > A long time ago I talked to Alan Cox about modifying this option so it > could be done at run-time, and he seemed agreeable. The mips port has a > similar issue in that only the lower 512MB of RAM is direct-mapped, so a > run-time decision would help them too (though it would be based on free > pages and not processor variant). Oh, great. That would be really convenient. >> Also, an update on the G5 port: the PMAP stuff is done to the point >> where the kernel boots all the way to panicing about not having a PIC, >> which is late in the boot process and implies that only device support >> remains. Trap handling is up and running as well. And (with the >> exception of UMA_MD_SMALL_ALLOC) the same kernel also boots on my G3. > > Fantastic ! Post some patches, I'll give it a try. > > Have you changed the sync_icache code to dynamically switch to 128 > bytes for the G5 ? Yep. I'll post some patches later, once I've cleaned them up a little (they are a bit littered with printf(), /* code */ and #if 0 at the moment). -Nathan