On 16/09/16 18:08, James Morse wrote:
> Hi Akashi,
>
> On 07/09/16 05:29, AKASHI Takahiro wrote:
>> This patch adds arch specific descriptions about kdump usage on arm64
>> to kdump.txt.
>
>> diff --git a/Documentation/kdump/kdump.txt b/Documentation/kdump/kdump.txt
>
>> @@ -249,6 +249,13 @@ Dump-capture kernel config options (Arch Dependent, arm)
>>
>> AUTO_ZRELADDR=y
>>
>> +Dump-capture kernel config options (Arch Dependent, arm64)
>> +----------------------------------------------------------
>> +
>> +- Please note that kvm of the dump-capture kernel will not be enabled
>> + on non-VHE systems even if it is configured. This is because the CPU
>> + cannot be reset to EL2 on panic.
>
> Nit:
> cannot be -> will not be
>
> We could try to do this, but its more code that could prevent us reaching the
> kdump kernel, so we choose not to.
>
>
>> @@ -370,6 +381,9 @@ For s390x:
>> For arm:
>> "1 maxcpus=1 reset_devices"
>>
>> +For arm64:
>> + "1 maxcpus=1 reset_devices"
>> +
>
> 'maxcpus=1' is a bit fragile. Since 44dbcc93ab67145 ("arm64: Fix behavior of
> maxcpus=N") udev on ubuntu vivid (running on Juno) has taken it upon itself to
> bring the secondary cores online, even when booted with 'maxcpus=1'.
>
This looks pretty much like a bug to me and should get fixed on their site.
> Can we change the recomendation to "1 nosmp reset_devices"?
>
>
> Thanks,
>
> James
>
>
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