From owner-freebsd-arm@FreeBSD.ORG Wed Mar 6 17:08:04 2013 Return-Path: Delivered-To: freebsd-arm@freebsd.org Received: from mx1.freebsd.org (mx1.FreeBSD.org [8.8.178.115]) by hub.freebsd.org (Postfix) with ESMTP id 3752A90F for ; Wed, 6 Mar 2013 17:08:04 +0000 (UTC) (envelope-from ThomasSkibo@sbcglobal.net) Received: from nm10.access.bullet.mail.sp2.yahoo.com (nm10.access.bullet.mail.sp2.yahoo.com [98.139.44.137]) by mx1.freebsd.org (Postfix) with ESMTP id DD3F0838 for ; Wed, 6 Mar 2013 17:08:03 +0000 (UTC) Received: from [98.139.44.102] by nm10.access.bullet.mail.sp2.yahoo.com with NNFMP; 06 Mar 2013 17:08:03 -0000 Received: from [67.195.14.95] by tm7.access.bullet.mail.sp2.yahoo.com with NNFMP; 06 Mar 2013 17:08:03 -0000 Received: from [127.0.0.1] by smtp110.sbc.mail.gq1.yahoo.com with NNFMP; 06 Mar 2013 17:08:03 -0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=sbcglobal.net; s=s1024; t=1362589683; bh=d4eY1qJruM0QO5w53HO4WXklaAYQS8kWwlDx3ZmrMoc=; h=X-Yahoo-Newman-Id:X-Yahoo-Newman-Property:X-YMail-OSG:X-Yahoo-SMTP:Received:Message-ID:Date:From:User-Agent:MIME-Version:To:Subject:References:In-Reply-To:Content-Type:Content-Transfer-Encoding; b=R5NwxLQmPxiZZE1n+zI2El4DuY8tf+C9zpwsM94dHbHslYl4NwQSIgmS55ADcXhZp7y17HRhIuaPdU8Yul8G+NgM9LGZmWDmySsytMggtkslNbD1Ojqep39JuFx9mTysm0Uy2hXJ33Ivup0M8FC8INaAf6V/r+2lYGf0yumGDj4= X-Yahoo-Newman-Id: 280673.56747.bm@smtp110.sbc.mail.gq1.yahoo.com X-Yahoo-Newman-Property: ymail-3 X-YMail-OSG: 0FuQ80cVM1neGgOuWfmFqUCB5bQ3R1MIizyd0Rf2ERtGXcx sWx4bYmfckjVAV1pHG5Di2hupFaMH0GrtoHuagyQk5WRYFjJvk5_rsfqjz6i DbQsOypHOvFGv0GL4ZFFJ7wqJc_pFxM6DjU8xaOQ.EcwTv4Qj5Zun3LupYlI lI7nItLjfwCuvyEUyiflpqwZryTKBxVFyC2IXJEL.vdR.Usjz2IAzQhurJIs 4paQBIJZz5pkLN3f1RXX0bjhP2C09bgwnnNUZfTLqkE5gjah.kXN1PneZjBN 20e_0CaRh49UY.56.EKDk2mthYm6UWhODGEc.gCFnvuHJinxo_K0FbM7RL03 q3C3Uz_pyxlfvo4PyD9qJUTHJOm2CRN58I_.SJzlN8SOHXedD6tDPdFos1vk WBraIz_1j.2SmHsqjv6mumpIotax3fMCUa9Oq60orhznaYvJD3y8LC3UKzKK qP0CYAjr2zGp2zI7ws2ZDqfqaGlWKx2kI5iYMgUX65P28mAIf1_lWFyt8TA- - X-Yahoo-SMTP: tUxoRneswBA21azLM.3ybMESf0mC2bFhTbmt0VU5ervH0kqi5lo- Received: from [192.168.1.9] (ThomasSkibo@71.139.174.219 with plain) by smtp110.sbc.mail.gq1.yahoo.com with SMTP; 06 Mar 2013 09:08:03 -0800 PST Message-ID: <513777F4.60302@sbcglobal.net> Date: Wed, 06 Mar 2013 09:08:04 -0800 From: Thomas Skibo User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.8; rv:17.0) Gecko/20130216 Thunderbird/17.0.3 MIME-Version: 1.0 To: freebsd-arm@freebsd.org Subject: Re: Weird kernel mode data abort panic on Zedboard. References: <51354125.4060500@sbcglobal.net> <51358BEB.50603@sbcglobal.net> In-Reply-To: <51358BEB.50603@sbcglobal.net> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit X-BeenThere: freebsd-arm@freebsd.org X-Mailman-Version: 2.1.14 Precedence: list List-Id: Porting FreeBSD to the StrongARM Processor List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 06 Mar 2013 17:08:04 -0000 On 3/4/13 10:08 PM, Thomas Skibo wrote: > > Oleksandr Tymoshenko : >> >> Just a hunch here - looks like TLB entry is not update properly. Might >> be missing >> PTE_SYNC in pmap-v6.c. Or current PTE_SYNC implementation does not cover >> all requirements for your platform. I'd say latter - but without proper >> debugging >> it's just guesswork. >> > > Thanks. On my platform, PMAP_NEEDS_PTE_SYNC was 0 and I convinced > myself earlier that the page tables were properly configured with > write-through caching and didn't need PTE_SYNC() anyway. I've had a chance to look at this some more. According to the Cortex-A9 manual, when the MMU is configured for write-through cacheing, it goes directly to external memory to read the page-table. So, PMAP_NEEDS_PTE_SYNC=0 is correct for my platform but I need PTE_SYNC() for the call to cpu_drain_writebuf(). I looked around again for missing PTE_SYNC()s and the only thing suspicious to me is that vector_page_setprot() doesn't have one. I think when I forced PMAP_NEEDS_PTE_SYNC to 1, the (unnecessary) cache ops just changed the timing of some kind of race condition somewhere else. I'll try to see what the other threads are doing when it crashes. THanks, -- -------- Thomas Skibo ThomasSkibo@sbcglobal.net