sparc64: xl-hugepages

sparc64: xl-hugepages

Note: Resending this patch. There is no change in this patch since v1.

Jalap?no was verified repaired.

Now to find performance issues.

One performance issue is subordinate page table state (SPTS). The SPTS will
be tricky because of protection changes for COW and other. For example,
a 2Gb hugepage will have 1UL << (31-23) PMD entries. Do we want 256 IPI-s
for a hugepage TTE(pte) change?

Signed-off-by: Bob Picco <bpicco@meloft.net>
(cherry picked from commit ece059b2e2581a2dcda3fb1ca35cd31258f6ed03)

Conflicts:
    arch/sparc/include/asm/mmu_64.h
    arch/sparc/mm/fault_64.c

Signed-off-by: Vijay Kumar <vijay.ac.kumar@oracle.com>
Acked-by: Nitin Gupta <nitin.m.gupta@oracle.com>
Orabug: 22729791
Signed-off-by: Allen Pais <allen.pais@oracle.com>