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

[Mike Rapoport <rppt@kernel.org>]

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@kernel.org> wrote:
> 
> > From: Mike Rapoport <rppt@linux.ibm.com>
> > 
> > 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.