From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mx0a-001b2d01.pphosted.com (mx0a-001b2d01.pphosted.com [148.163.156.1]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 3rY6Mq0kMBzDq80 for ; Mon, 20 Jun 2016 20:21:26 +1000 (AEST) Received: from pps.filterd (m0098396.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.16.0.11/8.16.0.11) with SMTP id u5KAJ4B4090686 for ; Mon, 20 Jun 2016 06:21:25 -0400 Received: from e37.co.us.ibm.com (e37.co.us.ibm.com [32.97.110.158]) by mx0a-001b2d01.pphosted.com with ESMTP id 23n0mdpefc-1 (version=TLSv1.2 cipher=AES256-SHA bits=256 verify=NOT) for ; Mon, 20 Jun 2016 06:21:24 -0400 Received: from localhost by e37.co.us.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Mon, 20 Jun 2016 04:21:24 -0600 From: "Aneesh Kumar K.V" To: Michael Ellerman , Benjamin Herrenschmidt , Denis Kirjanov Cc: linuxppc-dev Subject: Re: unrecoverable exception on G5 with CONFIG_PPC_EARLY_DEBUG enabled In-Reply-To: <1466414623.27324.2.camel@ellerman.id.au> References: <1465216025.2658.7.camel@ellerman.id.au> <1466078830.19127.0.camel@ellerman.id.au> <1466116390.24271.27.camel@kernel.crashing.org> <1466127964.12899.5.camel@ellerman.id.au> <87eg7u8li9.fsf@skywalker.in.ibm.com> <1466414623.27324.2.camel@ellerman.id.au> Date: Mon, 20 Jun 2016 15:51:18 +0530 MIME-Version: 1.0 Content-Type: text/plain Message-Id: <87a8igyxcx.fsf@skywalker.in.ibm.com> List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Michael Ellerman writes: > On Sat, 2016-06-18 at 22:47 +0530, Aneesh Kumar K.V wrote: >> Michael Ellerman writes: >> > On Fri, 2016-06-17 at 08:33 +1000, Benjamin Herrenschmidt wrote: >> > > On Thu, 2016-06-16 at 22:49 +0300, Denis Kirjanov wrote: >> > > > - >> > > > +BEGIN_MMU_FTR_SECTION >> > > > + b 2f >> > > > +END_MMU_FTR_SECTION_IFSET(MMU_FTR_RADIX) >> > > > andi. r10,r12,MSR_RI /* check for unrecoverable exception >> > > > */ >> > > > beq- 2f >> > > >> > > Are we taking an SLB miss before we do the fixup maybe ? >> > >> > Yeah that's the only explanation that makes any sense. >> > >> > I think instead of patching down this low we should instead be redirecting SLB >> > misses to unknown_exception() when radix is enabled. Aneesh? >> >> The 2f branch ends up doing unrecoverable exception. Or are you >> suggesting something else ? > > I meant more like diverting to unknown_exception() higher up the call stack, but > that's complicated. > > How about this? Denis does this work? > > cheers > > diff --git a/arch/powerpc/kernel/exceptions-64s.S b/arch/powerpc/kernel/exceptions-64s.S > index 4c9440629128..8bcc1b457115 100644 > --- a/arch/powerpc/kernel/exceptions-64s.S > +++ b/arch/powerpc/kernel/exceptions-64s.S > @@ -1399,11 +1399,12 @@ END_MMU_FTR_SECTION_IFCLR(MMU_FTR_RADIX) > lwz r9,PACA_EXSLB+EX_CCR(r13) /* get saved CR */ > > mtlr r10 > -BEGIN_MMU_FTR_SECTION > - b 2f > -END_MMU_FTR_SECTION_IFSET(MMU_FTR_RADIX) > andi. r10,r12,MSR_RI /* check for unrecoverable exception */ > +BEGIN_MMU_FTR_SECTION > beq- 2f > +FTR_SECTION_ELSE > + b 2f > +ALT_MMU_FTR_SECTION_END_IFCLR(MMU_FTR_RADIX) > > .machine push > .machine "power4" I sent a patch which should get this problem fixed. http://mid.gmane.org/1466274479-5650-1-git-send-email-aneesh.kumar@linux.vnet.ibm.com -aneesh