Hello, There are a number of changes required to support larger page sizes, but this one I thought worth sending up right away. The code in pgtable-64.h assumes TASK_SIZE is always bigger than a first level PGDIR_SIZE. This is not the case for 64K pages, where task size is 40 bits (1TB) and a pgd entry can map 42 bits. This leads to USER_PTRS_PER_PGD being zero for 64K pages. If there is interest in other changes for 64K pages, I can send more. Signed-off-by: Peter Watkins