mm: add a NO_INHERIT flag to the PR_SET_MDWE prctl

This extends the current PR_SET_MDWE prctl arg with a bit to indicate that
the process doesn't want MDWE protection to propagate to children.

To implement this no-inherit mode, the tag in current->mm->flags must be
absent from MMF_INIT_MASK.  This means that the encoding for "MDWE but
without inherit" is different in the prctl than in the mm flags.  This
leads to a bit of bit-mangling in the prctl implementation.

Link: https://lkml.kernel.org/r/[email protected]
Signed-off-by: Florent Revest <[email protected]>
Reviewed-by: Kees Cook <[email protected]>
Reviewed-by: Catalin Marinas <[email protected]>
Cc: Alexey Izbyshev <[email protected]>
Cc: Anshuman Khandual <[email protected]>
Cc: Ayush Jain <[email protected]>
Cc: David Hildenbrand <[email protected]>
Cc: Greg Thelen <[email protected]>
Cc: Joey Gouly <[email protected]>
Cc: KP Singh <[email protected]>
Cc: Mark Brown <[email protected]>
Cc: Michal Hocko <[email protected]>
Cc: Peter Xu <[email protected]>
Cc: Ryan Roberts <[email protected]>
Cc: Szabolcs Nagy <[email protected]>
Cc: Topi Miettinen <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>

0 files changed, 0 insertions, 0 deletions