From mboxrd@z Thu Jan 1 00:00:00 1970 From: saiprakash.ranjan@codeaurora.org (Sai Prakash Ranjan) Date: Sun, 21 Oct 2018 09:16:59 +0530 Subject: [PATCH 0/6] Tracing register accesses with pstore and dynamic debug In-Reply-To: <20181020162719.GA49955@joelaf.mtv.corp.google.com> References: <20181020052535.GA155509@joelaf.mtv.corp.google.com> <1d3ddbe3-d3ac-aa3e-fc9e-36739ddd0c91@codeaurora.org> <20181020162719.GA49955@joelaf.mtv.corp.google.com> Message-ID: <15ec736d-bd54-5519-4b99-47dd161bc556@codeaurora.org> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On 10/20/2018 9:57 PM, Joel Fernandes wrote: > On Sat, Oct 20, 2018 at 12:02:37PM +0530, Sai Prakash Ranjan wrote: >> On 10/20/2018 10:55 AM, Joel Fernandes wrote: >>> On Sun, Sep 09, 2018 at 01:57:01AM +0530, Sai Prakash Ranjan wrote: >>>> Hi, >>>> >>>> This patch series adds Event tracing support to pstore and is continuation >>>> to the RFC patch introduced to add a new tracing facility for register >>>> accesses called Register Trace Buffer(RTB). Since we decided to not introduce >>>> a separate framework to trace register accesses and use existing framework >>>> like tracepoints, I have moved from RFC. Details of the RFC in link below: >>>> >>>> Link: https://lore.kernel.org/lkml/cover.1535119710.git.saiprakash.ranjan at codeaurora.org/ >>>> >>>> MSR tracing example given by Steven was helpful in using tracepoints for >>>> register accesses instead of using separate trace. But just having these >>>> IO traces would not help much unless we could have them in some persistent >>>> ram buffer for debugging unclocked access or some kind of bus hang or an >>>> unexpected reset caused by some buggy driver which happens a lot during >>>> initial development stages. By analyzing the last few entries of this buffer, >>>> we could identify the register access which is causing the issue. >>> >>> Hi Sai, >>> >>> I wanted to see if I could make some time to get your patches working. We are >>> hitting usecases that need something like this as well. Basically devices >>> hanging and then the ramdump does not tell us much, so in this case pstore >>> events can be really helpful. This usecase came up last year as well. >>> >>> Anyway while I was going through your patches, I cleaned up some pstore code >>> as well and I have 3 more patches on top of yours for this clean up. I prefer >>> we submit the patches together and sync our work together so that there is >>> least conflict. >>> >>> Here's my latest tree: >>> https://github.com/joelagnel/linux-kernel/commits/pstore-events >>> (note that I have only build tested the patches since I just wrote them and >>> its quite late in the night here ;-)) >>> >> >> Hi Joel, >> >> Thanks for looking into this. Sure, I will be happy to sync up with you on > > Thanks. And added a fourth patch in the tree too. > >> this. I can test your additional patches on top of my pstore patches. BTW, >> I'm still stuck at copying binary record into pstore and then extract it >> during read time. Seems like I'm missing something. > > Sure, push your latest somewhere and let me know. I'll try to get you unstuck. > Thanks Joel, I will push my changes and let you know in some time. -- QUALCOMM INDIA, on behalf of Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, hosted by The Linux Foundation