Re: [PATCH] MIPS: reserve the memblock right after the kernel

[Jinyang He]

Hi, Jiaxun,

On 11/13/2020 10:30 AM, Jiaxun Yang wrote:
> Hi all,
>
> 在 2020/11/11 22:52, Serge Semin 写道:
> > Hello Alexander
> >
> > On Tue, Nov 10, 2020 at 11:29:50AM +0100, Alexander Sverdlin wrote:
> > 2) The check_kernel_sections_mem() method can be removed. But it
> > should be done carefully. We at least need to try to find all the
> > platforms, which rely on its functionality.
> It have been more than 10 years since introducing this this check, but
> I believe there must be a reason at the time.
>
> Also currently we have some unmaintained platform and it's impossible
> to test on them for us.
>
> For Cavium's issue, I believe removing the page rounding can help.
> I'd suggest keep this method but remove the rounding part, also
> leave a warning or kernel taint when out of boundary kernel image
> is detected.
>
> Thanks.
>
> - Jiaxun
I found the first submission.
Commit: d3ff93380232 (mips: Make sure kernel memory is in iomem)
As I thought, this check is related to kdump. More directly, it is
related to the "mem=" parameter. Kexec-tools provide a "mem=" parameter
to limit the kernel location in kdump. But sometimes the memory may be not
enough and this check gives a way to ensure the capture kernel can
start rightly. Although "mem=" is not in kexec-tools now, I thought
it is also useful if someone use "mem=" to do other things.

Thanks,
Jinyang

> > -Sergey
> >
> > > --
> > > Best regards,
> > > Alexander Sverdlin.