Re: [PATCH v4 1/5] arm64: export memblock_reserve()d regions via /proc/iomem

[John Stultz]

On Tue, Aug 21, 2018 at 3:22 AM, James Morse <james.morse@xxxxxxx> wrote:
> On 08/21/2018 05:39 AM, John Stultz wrote:
>>
>> Since this patch landed, on the HiKey board at bootup I'm seeing:
>>
>> [    0.451884] WARNING: CPU: 1 PID: 1 at arch/arm64/kernel/setup.c:271
>> reserve_memblock_reserved_regions+0xd4/0x13c
...
>>  From skimming the patch, it seems this is maybe expected? Or should
>> this warning raise eyebrows? I can't quite figure it out.
>
> Ugh, sorry for the noise! This is warning that there is something wrong
> with our assumptions about what types of memory exist.
>
>
>> It seems to trigger on the pstore memory at 0x21f00000-0x21ffffff.
>
>
> ... pmem ...
>
>>
>> /proc/iomem now has:
>> ...
>> 07410000-21efffff : System RAM
>>    11000000-1113cfff : reserved
>
>
>> 21f00000-21ffffff : reserved
>
>
> ^ This entry is what triggered the warning.
>
> It expects that meblock_reserved() memory is also described as memory.
> (memblock keeps them as separate lists, so its possible to reserve
> memory that doesn't exist... which it looks like your system is doing)

So yea, I suspect the hikey dts isn't quite right here then. I've
always thought how it setup the memory was a bit strange:
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/arch/arm64/boot/dts/hisilicon/hi6220-hikey.dts#n30

So from your mail, I suspect the hole in the memory map for the pstore
buffer isn't correct, and we should rework that.

I'll give that a shot here and make sure pstore still works properly.

thanks
-john