[SPARC64]: Fix D-cache corruption in mremap

If we move a mapping from one virtual address to another,
and this changes the virtual color of the mapping to those
pages, we can see corrupt data due to D-cache aliasing.

Check for and deal with this by overriding the move_pte()
macro.  Set things up so that other platforms can cleanly
override the move_pte() macro too.

Signed-off-by: David S. Miller <davem@davemloft.net>

include/asm-generic/pgtable.h

diff --git a/include/asm-generic/pgtable.h b/include/asm-generic/pgtable.h
index 358e4d3..c2059a3 100644
--- a/include/asm-generic/pgtable.h
+++ b/include/asm-generic/pgtable.h
@@ -159,17 +159,8 @@
 #define lazy_mmu_prot_update(pte)	do { } while (0)
 #endif
 
-#ifndef __HAVE_ARCH_MULTIPLE_ZERO_PAGE
+#ifndef __HAVE_ARCH_MOVE_PTE
 #define move_pte(pte, prot, old_addr, new_addr)	(pte)
-#else
-#define move_pte(pte, prot, old_addr, new_addr)				\
-({									\
- 	pte_t newpte = (pte);						\
-	if (pte_present(pte) && pfn_valid(pte_pfn(pte)) &&		\
-			pte_page(pte) == ZERO_PAGE(old_addr))		\
-		newpte = mk_pte(ZERO_PAGE(new_addr), (prot));		\
-	newpte;								\
-})
 #endif
 
 /*