Messages in this thread | | | Subject | Re: [PATCH 2/2] acpi, apei: use appropriate pgprot_t to map GHES memory | From | "Zhang, Jonathan Zhixiong" <> | Date | Tue, 25 Aug 2015 10:30:04 -0700 |
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On 8/25/2015 1:59 AM, Ingo Molnar wrote: > > * Zhang, Jonathan Zhixiong <zjzhang@codeaurora.org> wrote: > >> >> >> On 8/22/2015 2:24 AM, Ingo Molnar wrote: >>> >>> * Jonathan (Zhixiong) Zhang <zjzhang@codeaurora.org> wrote: >>> >>>> From: "Jonathan (Zhixiong) Zhang" <zjzhang@codeaurora.org> >>>> >>>> With ACPI APEI firmware first handling, generic hardware error >>>> record is updated by firmware in GHES memory region. On an arm64 >>>> platform, firmware updates GHES memory region with uncached >>>> access attribute, and then Linux reads stale data from cache. >>> >>> This paragraph *still* doesn't parse for me. It's not any English >>> I can recognize: what is a 'With ACPI APEI firmware first handling'? >> APEI is ACPI Platform Error Interface; it is part of ACPI spec, >> defining the aspect of hardware error handling. "firmware first >> handling" is a terminology used in APEI. It describes such mechanism >> that when hardware error happens, firmware intersects/handles such >> hardware error, formulates hardware error record and writes the record >> to GHES memory region, notifies the kernel through NMI/interrupt, then >> the kernel GHES driver grabs the error record from the GHES memory >> region. > > Argh. So how about translating that to English and putting that misnomer into > scare quotes, and saying something like: > > If the ACPI APEI firmware handles the error first (called "firmware first > handling"), the generic hardware error record is updated by the firmware in the > GHES memory region. > > ( Also note all the missing articles I added for readability. The rest of the > changelog is missing articles as well. ) Thank you very much, Ingo. Input are taken. > >>> ... plus what this changelog still doesn't mention is the most important part >>> of any bug fix description: how does the user notice this in practice and why >>> does he care? >> >> The changelog mentioned that Linux would read stale data from cache. When stale >> data is read, kernel reports there is no new hardware error when there actually >> is. > > Note that this is the most valuable sentence so far, in this whole changelog and > discussion. And we needed how many emails to get to this point? > > obviously saying 'stale data' in itself does not mean much - it could mean a > harmless inconsistency nobody really cares about, or in fact it could mean > something more serious: Sure, makes sense. > >> [...] This may lead to further damage in various scenarios, such as error >> propagation caused data corruption. > > Please outline this better. How users are affected in practice is far more > important than any other detail. Yes, will do. I just sent out an update for your review. > > Thanks, > > Ingo >
-- Jonathan (Zhixiong) Zhang The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum, a Linux Foundation Collaborative Project
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