mm: disallow raw PFN mappings of huge/shared zeropage

Handling the huge/shared zeropage correctly in vmf_insert_pfn_pmd() and
vmf_insert_pfn_prot() is more involved.  We would need to check whether
the VMA allows it and keep the mapping read-only, similar to the checks in
vm_mixed_ok().

No in-tree user needs that support, so reject these mappings with
VM_FAULT_SIGBUS rather than complicate the code for now.

Link: https://lore.kernel.org/20260921054225.28537-1-lance.yang@linux.dev
Link: https://lore.kernel.org/all/20260917121010.60966-1-lance.yang@linux.dev/
Signed-off-by: Lance Yang <lance.yang@linux.dev>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Suggested-by: Kiryl Shutsemau (Meta) <kas@kernel.org>
Suggested-by: David Hildenbrand (Arm) <david@kernel.org>
Reviewed-by: Kiryl Shutsemau (Meta) <kas@kernel.org>
Acked-by: David Hildenbrand (Arm) <david@kernel.org>
Acked-by: Zi Yan <ziy@nvidia.com>
Reviewed-by: Lorenzo Stoakes (ARM) <ljs@kernel.org>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Barry Song <baohua@kernel.org>
Cc: Dev Jain <dev.jain@arm.com>
Cc: Liam Howlett <liam@infradead.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: "Mike Rapoport (IBM)" <rppt@kernel.org>
Cc: Nico Pache (Red Hat) <nico.pache@linux.dev>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Usama Arif <usama.arif@linux.dev>
Cc: "Vlastimil Babka (SUSE)" <vbabka@kernel.org>

0 files changed, 0 insertions, 0 deletions