sparc64: Support 2GB and 16GB page sizes for kernel linear mappings.

SPARC-T4 supports 2GB pages.

So convert kpte_linear_bitmap into an array of 2-bit values which
index into kern_linear_pte_xor.

Now kern_linear_pte_xor is used for 4 page size aligned regions,
4MB, 256MB, 2GB, and 16GB respectively.

Enabling 2GB pages is currently hardcoded using a check against
sun4v_chip_type.  In the future this will be done more cleanly
by interrogating the machine description which is the correct
way to determine this kind of thing.

Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/arch/sparc/mm/init_64.h b/arch/sparc/mm/init_64.h
index 3e1ac8b..0661aa6 100644
--- a/arch/sparc/mm/init_64.h
+++ b/arch/sparc/mm/init_64.h
@@ -8,12 +8,12 @@
 #define MAX_PHYS_ADDRESS	(1UL << 41UL)
 #define KPTE_BITMAP_CHUNK_SZ		(256UL * 1024UL * 1024UL)
 #define KPTE_BITMAP_BYTES	\
-	((MAX_PHYS_ADDRESS / KPTE_BITMAP_CHUNK_SZ) / 8)
+	((MAX_PHYS_ADDRESS / KPTE_BITMAP_CHUNK_SZ) / 4)
 #define VALID_ADDR_BITMAP_CHUNK_SZ	(4UL * 1024UL * 1024UL)
 #define VALID_ADDR_BITMAP_BYTES	\
 	((MAX_PHYS_ADDRESS / VALID_ADDR_BITMAP_CHUNK_SZ) / 8)
 
-extern unsigned long kern_linear_pte_xor[2];
+extern unsigned long kern_linear_pte_xor[4];
 extern unsigned long kpte_linear_bitmap[KPTE_BITMAP_BYTES / sizeof(unsigned long)];
 extern unsigned int sparc64_highest_unlocked_tlb_ent;
 extern unsigned long sparc64_kern_pri_context;