From: Hari Bathini <hbathini@linux.ibm.com>
To: "Oliver O'Halloran" <oohall@gmail.com>
Cc: Ananth N Mavinakayanahalli <ananth@linux.ibm.com>,
Mahesh J Salgaonkar <mahesh@linux.ibm.com>,
Vasant Hegde <hegdevasant@linux.ibm.com>,
linuxppc-dev <linuxppc-dev@ozlabs.org>,
Nicholas Piggin <npiggin@gmail.com>,
Daniel Axtens <dja@axtens.net>
Subject: Re: [PATCH v5 21/31] powernv/fadump: process architected register state data provided by firmware
Date: Tue, 10 Sep 2019 14:18:50 +0530 [thread overview]
Message-ID: <af1c8b69-7340-005e-12b1-5e7228b9ea3a@linux.ibm.com> (raw)
In-Reply-To: <CAOSf1CHjV5PM-rYJ_5-XHmZyBNO_H=Nw8X7+HoOZnL+D7pM-sg@mail.gmail.com>
On 09/09/19 9:03 PM, Oliver O'Halloran wrote:
> On Mon, Sep 9, 2019 at 11:23 PM Hari Bathini <hbathini@linux.ibm.com> wrote:
>>
>> On 04/09/19 5:50 PM, Michael Ellerman wrote:
>>> Hari Bathini <hbathini@linux.ibm.com> writes:
>>>
>>
>> [...]
>>
>>>> +/*
>>>> + * CPU state data is provided by f/w. Below are the definitions
>>>> + * provided in HDAT spec. Refer to latest HDAT specification for
>>>> + * any update to this format.
>>>> + */
>>>
>>> How is this meant to work? If HDAT ever changes the format they will
>>> break all existing kernels in the field.
>>>
>>>> +#define HDAT_FADUMP_CPU_DATA_VERSION 1
>>
>> Changes are not expected here. But this is just to cover for such scenario,
>> if that ever happens.
>
> The HDAT spec doesn't define the SPR numbers for NIA, MSR and the CR.
> As far as I can tell the values you've assumed here are chip-specific,
> non-architected SPR numbers that come from an array buried somewhere
> in the SBE codebase. I don't believe you for a second when you say
> that this will never change.
At least, the understanding is that this numbers not change across processor
generations. If something changes, it is supposed to be handled in SBE. Also,
I am told this numbers would be listed in the HDAT Spec. Not sure if that
happened yet though. Vasant, you have anything to add?
>> Also, I think it is a bit far-fetched to error out if versions mismatch.
>> Warning and proceeding sounds worthier because the changes are usually
>> backward compatible, if and when there are any. Will update accordingly...
>
> Literally the only reason I didn't drop the CPU DATA parts of the OPAL
> MPIPL series was because I assumed the kernel would do the sensible
> thing and reject or ignore the structure if it did not know how to
> parse the data.
I think, the changes if any, would have to be backward compatible for the sake
of sanity. Even if they are not, we are better off exporting the /proc/vmcore
with a warning and some crazy CPU register data (if parsing goes alright) than
no dump at all?
- Hari
next prev parent reply other threads:[~2019-09-10 8:52 UTC|newest]
Thread overview: 74+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-08-20 12:04 [PATCH v5 00/31] Add FADump support on PowerNV platform Hari Bathini
2019-08-20 12:04 ` [PATCH v5 01/31] powerpc/fadump: move internal macros/definitions to a new header Hari Bathini
2019-09-03 11:09 ` Michael Ellerman
2019-09-03 16:05 ` Hari Bathini
2019-08-20 12:04 ` [PATCH v5 02/31] powerpc/fadump: move internal code to a new file Hari Bathini
2019-09-03 11:09 ` Michael Ellerman
2019-09-03 16:05 ` Hari Bathini
2019-09-04 9:02 ` Mahesh Jagannath Salgaonkar
2019-09-04 18:26 ` Hari Bathini
2019-08-20 12:04 ` [PATCH v5 03/31] powerpc/fadump: Improve fadump documentation Hari Bathini
2019-08-20 12:04 ` [PATCH v5 04/31] pseries/fadump: move rtas specific definitions to platform code Hari Bathini
2019-08-20 12:04 ` [PATCH v5 05/31] pseries/fadump: introduce callbacks for platform specific operations Hari Bathini
2019-09-03 11:10 ` Michael Ellerman
2019-09-03 16:06 ` Hari Bathini
2019-09-06 6:39 ` Hari Bathini
2019-08-20 12:04 ` [PATCH v5 06/31] pseries/fadump: define register/un-register callback functions Hari Bathini
2019-09-03 11:10 ` Michael Ellerman
2019-09-03 17:15 ` Hari Bathini
2019-08-20 12:04 ` [PATCH v5 07/31] powerpc/fadump: release all the memory above boot memory size Hari Bathini
2019-09-03 11:10 ` Michael Ellerman
2019-09-03 16:27 ` Hari Bathini
2019-08-20 12:05 ` [PATCH v5 08/31] pseries/fadump: move out platform specific support from generic code Hari Bathini
2019-08-20 12:05 ` [PATCH v5 09/31] powerpc/fadump: use FADump instead of fadump for how it is pronounced Hari Bathini
2019-08-20 12:05 ` [PATCH v5 10/31] opal: add MPIPL interface definitions Hari Bathini
2019-09-03 11:10 ` Michael Ellerman
2019-09-03 16:28 ` Hari Bathini
2019-09-04 11:03 ` Michael Ellerman
2019-09-04 11:05 ` Michael Ellerman
2019-08-20 12:05 ` [PATCH v5 11/31] powernv/fadump: add fadump support on powernv Hari Bathini
2019-09-03 11:10 ` Michael Ellerman
2019-09-03 16:31 ` Hari Bathini
2019-09-04 14:33 ` Hari Bathini
2019-09-05 3:11 ` Michael Ellerman
2019-08-20 12:05 ` [PATCH v5 12/31] powernv/fadump: register kernel metadata address with opal Hari Bathini
2019-09-04 11:25 ` Michael Ellerman
2019-08-20 12:05 ` [PATCH v5 13/31] powernv/fadump: reset metadata address during clean up Hari Bathini
2019-08-27 12:00 ` Hari Bathini
2019-08-20 12:05 ` [PATCH v5 14/31] powernv/fadump: define register/un-register callback functions Hari Bathini
2019-09-05 4:15 ` Michael Ellerman
2019-09-05 7:23 ` Michael Ellerman
2019-09-05 9:54 ` Hari Bathini
2019-08-20 12:05 ` [PATCH v5 15/31] powernv/fadump: support copying multiple kernel boot memory regions Hari Bathini
2019-09-04 11:30 ` Michael Ellerman
2019-09-04 20:20 ` Hari Bathini
2019-09-05 3:13 ` Michael Ellerman
2019-08-20 12:06 ` [PATCH v5 16/31] powernv/fadump: process the crashdump by exporting it as /proc/vmcore Hari Bathini
2019-09-04 11:42 ` Michael Ellerman
2019-09-04 21:01 ` Hari Bathini
2019-08-20 12:06 ` [PATCH v5 17/31] powernv/fadump: Warn before processing partial crashdump Hari Bathini
2019-09-04 11:48 ` Michael Ellerman
2019-08-20 12:06 ` [PATCH v5 18/31] powernv/fadump: handle invalidation of crashdump and re-registraion Hari Bathini
2019-08-20 12:06 ` [PATCH v5 19/31] powerpc/fadump: Update documentation about OPAL platform support Hari Bathini
2019-09-04 11:51 ` Michael Ellerman
2019-09-04 12:08 ` Oliver O'Halloran
2019-09-05 3:15 ` Michael Ellerman
2019-08-20 12:06 ` [PATCH v5 20/31] powerpc/fadump: use smaller offset while finding memory for reservation Hari Bathini
2019-09-04 11:54 ` Michael Ellerman
2019-08-20 12:06 ` [PATCH v5 21/31] powernv/fadump: process architected register state data provided by firmware Hari Bathini
2019-09-04 12:20 ` Michael Ellerman
2019-09-09 13:23 ` Hari Bathini
2019-09-09 15:33 ` Oliver O'Halloran
2019-09-10 8:48 ` Hari Bathini [this message]
2019-09-10 14:05 ` Michael Ellerman
2019-09-10 16:10 ` Hari Bathini
2019-08-20 12:06 ` [PATCH v5 22/31] powerpc/fadump: make crash memory ranges array allocation generic Hari Bathini
2019-08-20 12:06 ` [PATCH v5 23/31] powerpc/fadump: consider reserved ranges while releasing memory Hari Bathini
2019-08-20 12:07 ` [PATCH v5 24/31] powerpc/fadump: improve how crashed kernel's memory is reserved Hari Bathini
2019-08-20 12:07 ` [PATCH v5 25/31] powernv/fadump: add support to preserve crash data on FADUMP disabled kernel Hari Bathini
2019-08-20 12:07 ` [PATCH v5 26/31] powerpc/fadump: update documentation about CONFIG_PRESERVE_FA_DUMP Hari Bathini
2019-08-20 12:07 ` [PATCH v5 27/31] powernv/opalcore: export /sys/firmware/opal/core for analysing opal crashes Hari Bathini
2019-08-20 12:07 ` [PATCH v5 28/31] powernv/opalcore: provide an option to invalidate /sys/firmware/opal/core file Hari Bathini
2019-08-20 12:07 ` [PATCH v5 29/31] powerpc/fadump: consider f/w load area Hari Bathini
2019-08-20 12:07 ` [PATCH v5 30/31] powernv/fadump: update documentation about option to release opalcore Hari Bathini
2019-08-20 12:07 ` [PATCH v5 31/31] powernv/fadump: support holes in kernel boot memory area Hari Bathini
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=af1c8b69-7340-005e-12b1-5e7228b9ea3a@linux.ibm.com \
--to=hbathini@linux.ibm.com \
--cc=ananth@linux.ibm.com \
--cc=dja@axtens.net \
--cc=hegdevasant@linux.ibm.com \
--cc=linuxppc-dev@ozlabs.org \
--cc=mahesh@linux.ibm.com \
--cc=npiggin@gmail.com \
--cc=oohall@gmail.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).