Re: [PATCH] docs/mm: describe set_memory() and set_direct_map() APIs

From: Mike Rapoport

Date: Wed Sep 09 2026 - 07:01:44 EST


On Wed, Sep 09, 2026 at 12:30:01PM +0200, David Hildenbrand (Arm) wrote:
> On 9/9/26 11:45, Mike Rapoport (Microsoft) wrote:
> > The set_memory() and set_direct_map() APIs change permissions of existing
> > kernel mappings, but their semantics are only described by the code, and
> > that code differs from architecture to architecture.
> >
> > Add Documentation/mm/kernel-page-tables.rst that briefly describes what the
> > kernel page tables consist of, defines the semantics both APIs have in
> > common, including the parts that are easy to get wrong, and lists the
> > differences between the architecture implementations.
> >
> > Add kernel-doc comments for the generic set_memory() and set_direct_map()
> > stubs and link them into Documentation/core-api/mm-api.rst.
> >
> > Assisted-by: copilot:claude-opus
> > Signed-off-by: Mike Rapoport (Microsoft) <rppt@xxxxxxxxxx>
> > ---
> > The semantics of set_memory() and set_direct_map() are currently described
> > only by the code, and the code differs from architecture to architecture.
> >
> > Document what these APIs actually promise, what they merely hint at, and how
> > the architectures disagree.
> >
> > The discussions that prompted this:
> >
> > https://lore.kernel.org/all/a98df077-3e97-4eea-8bfe-470bad9ff9e0@xxxxxxxxxx
> > https://lore.kernel.org/all/5026dbec-0b71-4408-a78a-484a4b8e77dd@xxxxxxxxx
> > ---
> > Documentation/core-api/mm-api.rst | 9 +
> > Documentation/mm/index.rst | 1 +
> > Documentation/mm/kernel-page-tables.rst | 402 ++++++++++++++++++++++++++++++++
>
> Before I read any of this, how much did you review and edit whatever the LLM
> came up with?

I never send something I don't like :)

> --
> Cheers,
>
> David

--
Sincerely yours,
Mike.