ARM: memblock: convert free_highpages() to use memblock

Free the high pages using the memblock memory lists - and more
importantly, exclude any memblock allocations in highmem from the
free'd memory.
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

arch/arm/mm/init.c

@@ -439,13 +439,47 @@ static void __init free_unused_memmap(struct meminfo *mi)
 static void __init free_highpages(void)
 {
 #ifdef CONFIG_HIGHMEM
-	int i;
+	unsigned long max_low = max_low_pfn + PHYS_PFN_OFFSET;
+	struct memblock_region *mem, *res;
 
 	/* set highmem page free */
-	for_each_bank (i, &meminfo) {
-		unsigned long start = bank_pfn_start(&meminfo.bank[i]);
-		unsigned long end = bank_pfn_end(&meminfo.bank[i]);
-		if (start >= max_low_pfn + PHYS_PFN_OFFSET)
+	for_each_memblock(memory, mem) {
+		unsigned long start = memblock_region_memory_base_pfn(mem);
+		unsigned long end = memblock_region_memory_end_pfn(mem);
+
+		/* Ignore complete lowmem entries */
+		if (end <= max_low)
+			continue;
+
+		/* Truncate partial highmem entries */
+		if (start < max_low)
+			start = max_low;
+
+		/* Find and exclude any reserved regions */
+		for_each_memblock(reserved, res) {
+			unsigned long res_start, res_end;
+
+			res_start = memblock_region_reserved_base_pfn(res);
+			res_end = memblock_region_reserved_end_pfn(res);
+
+			if (res_end < start)
+				continue;
+			if (res_start < start)
+				res_start = start;
+			if (res_start > end)
+				res_start = end;
+			if (res_end > end)
+				res_end = end;
+			if (res_start != start)
+				totalhigh_pages += free_area(start, res_start,
+							     NULL);
+			start = res_end;
+			if (start == end)
+				break;
+		}
+
+		/* And now free anything which remains */
+		if (start < end)
 			totalhigh_pages += free_area(start, end, NULL);
 	}
 	totalram_pages += totalhigh_pages;