[RFC PATCH 0/3] makedumpfile: about failing on arm64 with kernel > 5.4

[Bhupesh SHARMA]

Hi Alexander,

Thanks for the patchset.
I am not sure why this new patchset is needed for makedumpfile
upstream - if you need a separate patchset for Yocto please feel free
to submit it to the Yocto list and Cc us.

However for upstream makedumpfile project these are _probably_ not
required - I have tested my patch on several arm64 boards and it works
fine there.

I will send the next version of my patch once I am back from my
holidays later this week.
If you see any breakage with the same, please feel free to report here
with relevant logs and I can help further

Thanks,
Bhupesh

On Mon, Nov 23, 2020 at 10:10 AM Alexander Kamensky
<alexander.kamensky42 at gmail.com> wrote:
>
> Hi Kazu, Bhupesh,
>
> I am hitting the linear mapping swap issue with makedumpfile failing on
> arm64 Yocto Project qemuarm64 machine with 5.8 kernel as it was discussed
> several times on this mailing list:
>
> root at qemuarm64:~# makedumpfile -c -F /proc/vmcore > /dev/null
> readpage_elf: Attempt to read non-existent page at 0x0.
> readmem: type_addr: 1, addr:440, size:8
> vaddr_to_paddr_arm64: Can't read pmd
> readmem: Can't convert a virtual address(ffffffc01107f94c) to physical address.
> readmem: type_addr: 0, addr:ffffffc01107f94c, size:390
> check_release: Can't get the address of system_utsname.
>
> I've have tried Bhupesh's remaining third patch [1] from [2] series,
> it does help. But I am a bit hesitant to submit it to the Yocto Project,
> since Kazu pointed out [3] that this patch uses current kernel version to
> make decision how __pa is handled and it may mismatch the version where
> vmcore was collected, and in such case it may not operate correctly.
>
> In this RFC series I have tried to implement Kazu's suggestion and use
> kernel version retrieved from OSRELEASE string from vmcoreinfo note. I
> wonder whether it will help to merge arm64 5.4+ makedumpfile fix? Is
> there anything else outstanding that prevents such merge?
>
> My RFC patches series does include Bhupesh's patch [1], and I posted
> my modifications on top of it as separate patch for readability.
>
> Thanks,
> Alexander
>
> [1] http://lists.infradead.org/pipermail/kexec/2020-September/021336.html
> [2] http://lists.infradead.org/pipermail/kexec/2020-September/021333.html
> [3] http://lists.infradead.org/pipermail/kexec/2020-September/021488.html
>
> Alexander Kamensky (2):
>   added way to determine kernel version that vmcore is from
>   arm64: use kernel version from OSRELEASE to determine linear mapping
>     position
>
> Bhupesh Sharma (1):
>   makedumpfile/arm64: Add support for ARMv8.2-LVA (52-bit kernel VA
>     support)
>
>  arch/arm64.c   | 229 ++++++++++++++++++++++++++++++++++++++++++-------
>  common.h       |  10 +++
>  makedumpfile.c |  23 +++++
>  makedumpfile.h |   6 +-
>  4 files changed, 234 insertions(+), 34 deletions(-)
>
> --
> 2.26.2
>
>
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