[IA64] align high endpoint of VIRTUAL_MEM_MAP

Assure that vmem_map's high endpoint is MAX_ORDER aligned. Not doing so violates
the buddy allocator algorithm. Also anyone using mem=XXX on boot line and
not aligned to MAX_ORDER requires this patch in order to satisfy buddy
allocator. vmem_map always starts at pfn 0. The potentially large MAX_ORDER
on ia64 (due to hugetlbfs) requires that the end of vmem_map be aligned
to MAX_ORDER_NR_PAGES.

This was boot tested for: FLATMEM, FLATMEM+VIRTUAL_MEM_MAP,
DISCONTIGMEM+VIRTUAL_MEM_MAP and SPARSEMEM.
Signed-off-by: Bob Picco <bob.picco@hp.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>

arch/ia64/mm/contig.c

@@ -277,7 +277,8 @@ paging_init (void)
 
 		/* allocate virtual_mem_map */
 
-		map_size = PAGE_ALIGN(max_low_pfn * sizeof(struct page));
+		map_size = PAGE_ALIGN(ALIGN(max_low_pfn, MAX_ORDER_NR_PAGES) *
+			sizeof(struct page));
 		vmalloc_end -= map_size;
 		vmem_map = (struct page *) vmalloc_end;
 		efi_memmap_walk(create_mem_map_page_table, NULL);

arch/ia64/mm/discontig.c

@@ -751,7 +751,8 @@ void __init paging_init(void)
 	efi_memmap_walk(filter_rsvd_memory, count_node_pages);
 
 #ifdef CONFIG_VIRTUAL_MEM_MAP
-	vmalloc_end -= PAGE_ALIGN(max_low_pfn * sizeof(struct page));
+	vmalloc_end -= PAGE_ALIGN(ALIGN(max_low_pfn, MAX_ORDER_NR_PAGES) *
+		sizeof(struct page));
 	vmem_map = (struct page *) vmalloc_end;
 	efi_memmap_walk(create_mem_map_page_table, NULL);
 	printk("Virtual mem_map starts at 0x%p\n", vmem_map);