Re: [PATCH RFC] mm: add MAP_EXCLUSIVE to create exclusive user mappings

Kirill A. Shutemov
2019-10-28T12:31:26Z

On Sun, Oct 27, 2019 at 12:17:32PM +0200, Mike Rapoport wrote:
> From: Mike Rapoport <rppt@linux.ibm.com>
>
> The mappings created with MAP_EXCLUSIVE are visible only in the context of
> the owning process and can be used by applications to store secret
> information that will not be visible not only to other processes but to the
> kernel as well.
>
> The pages in these mappings are removed from the kernel direct map and
> marked with PG_user_exclusive flag. When the exclusive area is unmapped,
> the pages are mapped back into the direct map.

I probably blind, but I don't see where you manipulate direct map...

--
Kirill A. Shutemov