Re: [PATCH v20 4/7] mm: introduce memfd_secret system call to create "secret" memory areas

From: Mike Rapoport
Date: Tue May 18 2021 - 23:50:59 EST


On Tue, May 18, 2021 at 05:44:22PM -0700, Andrew Morton wrote:
> On Tue, 18 May 2021 10:20:31 +0300 Mike Rapoport <rppt@xxxxxxxxxx> wrote:
>
> > From: Mike Rapoport <rppt@xxxxxxxxxxxxx>
> >
> > Introduce "memfd_secret" system call with the ability to create memory
> > areas visible only in the context of the owning process and not mapped not
> > only to other processes but in the kernel page tables as well.
> >
> > ...
> >
> > --- a/mm/Kconfig
> > +++ b/mm/Kconfig
> > @@ -901,4 +901,9 @@ config KMAP_LOCAL
> > # struct io_mapping based helper. Selected by drivers that need them
> > config IO_MAPPING
> > bool
> > +
> > +config SECRETMEM
> > + def_bool ARCH_HAS_SET_DIRECT_MAP && !EMBEDDED
> > + select STRICT_DEVMEM
> > +
> > endmenu
>
> WARNING: unmet direct dependencies detected for STRICT_DEVMEM
> Depends on [n]: MMU [=y] && DEVMEM [=n] && (ARCH_HAS_DEVMEM_IS_ALLOWED [=y] || GENERIC_LIB_DEVMEM_IS_ALLOWED [=n])
> Selected by [y]:
> - SECRETMEM [=y]
>
> so I went back to the v19 version, with

Ouch, sorry, I forgot to remove that hunk, v19 is the correct version.

> --- a/mm/Kconfig~mm-introduce-memfd_secret-system-call-to-create-secret-memory-areas-fix
> +++ a/mm/Kconfig
> @@ -907,6 +907,5 @@ config IO_MAPPING
>
> config SECRETMEM
> def_bool ARCH_HAS_SET_DIRECT_MAP && !EMBEDDED
> - select STRICT_DEVMEM
>
> endmenu
> _
>

--
Sincerely yours,
Mike.