[PATCH v2 00/12] 52-bit kernel + user VAs

Bhupesh Sharma bhsharma at redhat.com
Mon Jun 10 04:15:10 PDT 2019


Hi Catalin,

On Mon, Jun 10, 2019 at 4:24 PM Catalin Marinas <catalin.marinas at arm.com> wrote:
>
> On Mon, Jun 10, 2019 at 04:10:50PM +0530, Bhupesh Sharma wrote:
> > On 05/28/2019 09:40 PM, Steve Capper wrote:
> > >   2) How can this memory map be advertised to kdump tools/documentation?
> > >      I was planning on getting the kernel VA structure agreed on, then I
> > >      would add the relevant exports/documentation.
> >
> > Indeed, in the absence of corresponding changes to the Documentation
> > section, it is hard to visualize the changes being made in the memory
> > map.
>
> We used to have some better documentation in the arm64 memory.txt until
> commit 08375198b010 ("arm64: Determine the vmalloc/vmemmap space at
> build time based on VA_BITS") which removed it in favour of what the
> kernel was printing. Subsequently, the kernel VA layout printing was
> also removed. It would be nice to bring back the memory.txt, even if it
> is for a single configuration as per defconfig.

Indeed, that's what I suggested during the v1 review as well. See
<https://www.spinics.net/lists/arm-kernel/msg718096.html> for details.

Also, we may want to have a doc dedicated to 52-bit address space
details on arm64, similar to what we have currently for x86 (see [1a]
and [1b])

[1a]. https://github.com/torvalds/linux/blob/master/Documentation/x86/x86_64/5level-paging.txt
[1b].https://github.com/torvalds/linux/blob/master/Documentation/x86/x86_64/mm.txt

Thanks,
Bhupesh



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