Re: [POC][RFC][PATCH 0/2] pstore/mm/x86: Add wildcard memmap to map pstore consistently

[Steven Rostedt]

On Thu, 11 Apr 2024 16:11:55 -0300
"Guilherme G. Piccoli" <gpiccoli@xxxxxxxxxx> wrote:

> Thanks Steve! Like Kees, I've been wanting a consistent way of mapping
> some RAM for pstore for a while, without resorting to platform drivers
> like Chromebooks do...

Great!

> 
> The idea seems very interesting and helpful, I'll test it here. My only
> concern / "complain" is that it's currently only implemented for builtin
> ramoops, which is not the default in many distros (like Arch, Ubuntu,
> Debian). I read patch 2 (and discussion), so I think would be good to
> have that builtin helper implemented upfront to allow modular usage of
> ramoops.

What I think I could do is to have a check after memory is allocated to
copy the table mapping (in the heap) if it is filled. The reason I did it
this way was because it was the easiest way to save the label to address
memory before memory is initialized. I use a __initdata array (why waste
memory if it's hardly ever used).

But, after memory is initialized, we can check if the table has content,
and if so allocate a copy and store it there and use that table instead.
That would give modules a way to find the address as well.

-- Steve