Re: [PATCH] mseal sysmap: add arch-support txt

[Jeff Xu <jeffxu@chromium.org>]

On Wed, Mar 12, 2025 at 10:21 PM Lorenzo Stoakes
<lorenzo.stoakes@oracle.com> wrote:
>
> On Thu, Mar 13, 2025 at 12:06:23AM +0000, jeffxu@chromium.org wrote:
> > From: Jeff Xu <jeffxu@chromium.org>
> >
> > Add Documentation/features/core/mseal_sys_mappings/arch-support.txt
> >
> > Signed-off-by: Jeff Xu <jeffxu@chromium.org>
> > ---
> >  .../core/mseal_sys_mappings/arch-support.txt  | 30 +++++++++++++++++++
> >  1 file changed, 30 insertions(+)
> >  create mode 100644 Documentation/features/core/mseal_sys_mappings/arch-support.txt
> >
> > diff --git a/Documentation/features/core/mseal_sys_mappings/arch-support.txt b/Documentation/features/core/mseal_sys_mappings/arch-support.txt
> > new file mode 100644
> > index 000000000000..8db637254de9
> > --- /dev/null
> > +++ b/Documentation/features/core/mseal_sys_mappings/arch-support.txt
> > @@ -0,0 +1,30 @@
> > +#
> > +# Feature name:          mseal-system-mappings
> > +#         Kconfig:       ARCH_SUPPORTS_MSEAL_SYSTEM_MAPPINGS
> > +#         description:   arch supports mseal system mappings
> > +#
> > +    -----------------------
> > +    |         arch |status|
> > +    -----------------------
> > +    |       alpha: | TODO |
> > +    |         arc: | TODO |
> > +    |         arm: |  N/A |
> > +    |       arm64: |  ok  |
> > +    |        csky: | TODO |
> > +    |     hexagon: | TODO |
> > +    |   loongarch: | TODO |
> > +    |        m68k: | TODO |
> > +    |  microblaze: | TODO |
> > +    |        mips: | TODO |
> > +    |       nios2: | TODO |
> > +    |    openrisc: | TODO |
> > +    |      parisc: | TODO |
> > +    |     powerpc: | TODO |
> > +    |       riscv: | TODO |
> > +    |        s390: |  ok  |
> > +    |          sh: | TODO |
> > +    |       sparc: | TODO |
> > +    |          um: | TODO |
> > +    |         x86: |  ok  |
> > +    |      xtensa: | TODO |
> > +    -----------------------
> > --
> > 2.49.0.rc0.332.g42c0ae87b1-goog
> >
>
> I mean fine, but why not in the existing mseal documentation file where you
> already document system mappings?
>
you mean adding s390 in the mseal.rst ? I thought Heiko was going to
add that ? [1], maybe not ?

From the example given by Heiko [1] , arch-support.txt is the official
way of documenting arch specific support. But adding these info in
mseal.rst won't hurt.

> Plus I feel this need expansion a bit 'N/A' is because of being non-64 bit
> right?
>
Below is the definition of N/A in Documentation/features/arch-support.txt
   | N/A|  # feature doesn't apply to the architecture

It fits the arm case because mseal is not supported in 32 bit.

> Actually this will change soon btw, based on Matthew's idea I plan to drop the
> 32-bit vma flags limit.
>
Okay, we can update this section to TODO when 32-bit vma flags are
expanded. Based on past comments, I gather we want the document to
reflect the current state of the kernel, not future features.

> Anyway yeah, let's move that over there please.

I'm looking at Heiko's direction first to see if mseal.rst will be
updated as part of the s390 patch, technically that belongs to Heiko's
patch series. I can also add that if Heiko doesn't care :-)

Thanks
-Jeff

[1]https://lore.kernel.org/all/20250312153946.10610B02-hca@linux.ibm.com/