x86, mm: Separate out calculate_table_space_size()

It should take physical address range that will need to be mapped.
find_early_table_space should take range that pgt buff should be in.

Separating page table size calculating and finding early page table to
reduce confusing.

Signed-off-by: Yinghai Lu <yinghai@kernel.org>
Link: http://lkml.kernel.org/r/1353123563-3103-9-git-send-email-yinghai@kernel.org
Reviewed-by: Pekka Enberg <penberg@kernel.org>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>

arch/x86/mm/init.c

@@ -196,12 +196,10 @@ static int __meminit split_mem_range(struct map_range *mr, int nr_range,
  * mr[0].start to mr[nr_range - 1].end, while accounting for possible 2M and 1GB
  * pages. Then find enough contiguous space for those page tables.
  */
-static void __init find_early_table_space(unsigned long start, unsigned long end)
+static unsigned long __init calculate_table_space_size(unsigned long start, unsigned long end)
 {
 	int i;
 	unsigned long puds = 0, pmds = 0, ptes = 0, tables;
-	unsigned long good_end;
-	phys_addr_t base;
 	struct map_range mr[NR_RANGE_MR];
 	int nr_range;
 
@@ -240,20 +238,24 @@ static void __init find_early_table_space(unsigned long start, unsigned long end
 #ifdef CONFIG_X86_32
 	/* for fixmap */
 	tables += roundup(__end_of_fixed_addresses * sizeof(pte_t), PAGE_SIZE);
-	good_end = max_pfn_mapped << PAGE_SHIFT;
 #endif
 
+	return tables;
+}
+
+static void __init find_early_table_space(unsigned long start,
+					  unsigned long good_end,
+					  unsigned long tables)
+{
+	phys_addr_t base;
+
 	base = memblock_find_in_range(start, good_end, tables, PAGE_SIZE);
 	if (!base)
 		panic("Cannot find space for the kernel page tables");
 
 	pgt_buf_start = base >> PAGE_SHIFT;
 	pgt_buf_end = pgt_buf_start;
 	pgt_buf_top = pgt_buf_start + (tables >> PAGE_SHIFT);
-
-	printk(KERN_DEBUG "kernel direct mapping tables up to %#lx @ [mem %#010lx-%#010lx]\n",
-		mr[nr_range - 1].end - 1, pgt_buf_start << PAGE_SHIFT,
-		(pgt_buf_top << PAGE_SHIFT) - 1);
 }
 
 /*
@@ -291,6 +293,8 @@ unsigned long __init_refok init_memory_mapping(unsigned long start,
 
 void __init init_mem_mapping(void)
 {
+	unsigned long tables, good_end, end;
+
 	probe_page_size_mask();
 
 	/*
@@ -301,10 +305,18 @@ void __init init_mem_mapping(void)
 	 * nodes are discovered.
 	 */
 #ifdef CONFIG_X86_64
-	find_early_table_space(0, max_pfn<<PAGE_SHIFT);
+	end = max_pfn << PAGE_SHIFT;
+	good_end = end;
 #else
-	find_early_table_space(0, max_low_pfn<<PAGE_SHIFT);
+	end = max_low_pfn << PAGE_SHIFT;
+	good_end = max_pfn_mapped << PAGE_SHIFT;
 #endif
+	tables = calculate_table_space_size(0, end);
+	find_early_table_space(0, good_end, tables);
+	printk(KERN_DEBUG "kernel direct mapping tables up to %#lx @ [mem %#010lx-%#010lx] prealloc\n",
+		end - 1, pgt_buf_start << PAGE_SHIFT,
+		(pgt_buf_top << PAGE_SHIFT) - 1);
+
 	max_low_pfn_mapped = init_memory_mapping(0, max_low_pfn<<PAGE_SHIFT);
 	max_pfn_mapped = max_low_pfn_mapped;
 
@@ -331,9 +343,13 @@ void __init init_mem_mapping(void)
 	 * RO all the pagetable pages, including the ones that are beyond
 	 * pgt_buf_end at that time.
 	 */
-	if (pgt_buf_end > pgt_buf_start)
+	if (pgt_buf_end > pgt_buf_start) {
+		printk(KERN_DEBUG "kernel direct mapping tables up to %#lx @ [mem %#010lx-%#010lx] final\n",
+			end - 1, pgt_buf_start << PAGE_SHIFT,
+			(pgt_buf_end << PAGE_SHIFT) - 1);
 		x86_init.mapping.pagetable_reserve(PFN_PHYS(pgt_buf_start),
 				PFN_PHYS(pgt_buf_end));
+	}
 
 	/* stop the wrong using */
 	pgt_buf_top = 0;