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Violators will be prosecuted; Fri, 17 Mar 2017 01:25:21 -0400 Received: from b01ledav004.gho.pok.ibm.com (b01ledav004.gho.pok.ibm.com [9.57.199.109]) by b01cxnp23032.gho.pok.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id v2H5PLoG41943290; Fri, 17 Mar 2017 05:25:21 GMT Received: from b01ledav004.gho.pok.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 2AC16112057; Fri, 17 Mar 2017 01:25:20 -0400 (EDT) Received: from thinktux.in.ibm.com (unknown [9.199.36.131]) by b01ledav004.gho.pok.ibm.com (Postfix) with ESMTP id C419F112047; Fri, 17 Mar 2017 01:25:19 -0400 (EDT) Received: by thinktux.in.ibm.com (Postfix, from userid 1000) id 588121A1805; Fri, 17 Mar 2017 10:55:15 +0530 (IST) Date: Fri, 17 Mar 2017 10:55:15 +0530 From: Ananth N Mavinakayanahalli To: Patrick Williams Cc: openbmc@lists.ozlabs.org, mahesh@linux.vnet.ibm.com, vsainath@linux.vnet.ibm.com Subject: Re: Out-of-band SRESET Reply-To: ananth@linux.vnet.ibm.com References: <20170316080252.GB24841@in.ibm.com> <20170316153756.j7zqd7ldhrfwqvii@asimov> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20170316153756.j7zqd7ldhrfwqvii@asimov> User-Agent: Mutt/1.5.21 (2010-09-15) X-TM-AS-GCONF: 00 x-cbid: 17031705-0056-0000-0000-0000031210A4 X-IBM-SpamModules-Scores: X-IBM-SpamModules-Versions: BY=3.00006796; HX=3.00000240; KW=3.00000007; PH=3.00000004; SC=3.00000206; SDB=6.00834972; UDB=6.00410107; IPR=6.00612628; BA=6.00005215; NDR=6.00000001; ZLA=6.00000005; ZF=6.00000009; ZB=6.00000000; ZP=6.00000000; ZH=6.00000000; ZU=6.00000002; MB=3.00014686; XFM=3.00000013; UTC=2017-03-17 05:25:23 X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 17031705-0057-0000-0000-000007481122 Message-Id: <20170317052515.GC24841@in.ibm.com> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10432:, , definitions=2017-03-17_04:, , signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 spamscore=0 suspectscore=0 malwarescore=0 phishscore=0 adultscore=0 bulkscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1702020001 definitions=main-1703170045 X-BeenThere: openbmc@lists.ozlabs.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: Development list for OpenBMC List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 17 Mar 2017 05:25:31 -0000 On Thu, Mar 16, 2017 at 10:37:56AM -0500, Patrick Williams wrote: > On Thu, Mar 16, 2017 at 01:32:52PM +0530, Ananth N Mavinakayanahalli wrote: > > Hi, > > > > One requirement from a OpenPOWER service point-of-view is to be able to > > trigger an out-of-band SRESET on a unresponsive system. We can then have > > the necessary plumbing in the host Linux kernel to either drop the > > machine into a debugger or trigger a dump capture, if configured. > > > > On P9, this would translate to a series of SCOM operations for the SBE > > It would be good to have a REST API defined to cater to this specific > > purpose. > > > > The API should cater to: > > - SRESET a core > > - SRESET a chip > > - SRESET all cores > > > > Thoughts? > > > > Regards, > > Ananth > > > > Ananth, > > I understand the desire from your end with respect to debugging the > host. Is there something we can do to model this better from a REST > perspective to make this less Power-specific? Do other architectures > also have a "send debug interrupt"? Any option that says nmi for x86 can apply here, IMO. > Do you need to SRESET targeting an SMT thread? We will need to come up > with some kind of identifier for sending the debug interrupts. For starters, we will be using the SRESET as an unrecoverable entity -- option of last resort. The SRESET all cores will be the most used, but I can envisage cases where we would need specific cores/threads to be forced into xmon or such. While it is good to have the design to be able to accommodate it, targeted SMT thread reset isn't a 'must have' to begin with. Ananth