sparc64: Add 16GB hugepage support

Adds support for 16GB hugepage size. To use this page size
use kernel parameters as:

default_hugepagesz=16G hugepagesz=16G hugepages=10

Testing:

Tested with the stream benchmark which allocates 48G of
arrays backed by 16G hugepages and does RW operation on
them in parallel.

Orabug: 25362942

Cc: Anthony Yznaga <anthony.yznaga@oracle.com>
Reviewed-by: Bob Picco <bob.picco@oracle.com>
Signed-off-by: Nitin Gupta <nitin.m.gupta@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

arch/sparc/kernel/head_64.S

@@ -893,7 +893,6 @@ sparc64_boot_end:
 #include "misctrap.S"
 #include "syscalls.S"
 #include "helpers.S"
-#include "hvcalls.S"
 #include "sun4v_tlb_miss.S"
 #include "sun4v_ivec.S"
 #include "ktlb.S"
@@ -938,6 +937,7 @@ swapper_4m_tsb:
 
 ! 0x0000000000428000
 
+#include "hvcalls.S"
 #include "systbls_64.S"
 
 	.data

arch/sparc/kernel/tsb.S

@@ -117,7 +117,7 @@ tsb_miss_page_table_walk_sun4v_fastpath:
 	/* Valid PTE is now in %g5.  */
 
 #if defined(CONFIG_HUGETLB_PAGE) || defined(CONFIG_TRANSPARENT_HUGEPAGE)
-	sethi		%uhi(_PAGE_PMD_HUGE), %g7
+	sethi		%uhi(_PAGE_PMD_HUGE | _PAGE_PUD_HUGE), %g7
 	sllx		%g7, 32, %g7
 
 	andcc		%g5, %g7, %g0

arch/sparc/kernel/vmlinux.lds.S

@@ -154,6 +154,11 @@ SECTIONS
 		*(.get_tick_patch)
 		__get_tick_patch_end = .;
 	}
+	.pud_huge_patch : {
+		__pud_huge_patch = .;
+		*(.pud_huge_patch)
+		__pud_huge_patch_end = .;
+	}
 	PERCPU_SECTION(SMP_CACHE_BYTES)
 
 #ifdef CONFIG_JUMP_LABEL