mm/memblock: add physical memory list

Add the physmem list to the memblock structure. This list only exists
if HAVE_MEMBLOCK_PHYS_MAP is selected and contains the unmodified
list of physically available memory. It differs from the memblock
memory list as it always contains all memory ranges even if the
memory has been restricted, e.g. by use of the mem= kernel parameter.
Signed-off-by: Philipp Hachtmann <phacht@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

include/linux/memblock.h

@@ -18,6 +18,7 @@
 #include <linux/mm.h>
 
 #define INIT_MEMBLOCK_REGIONS	128
+#define INIT_PHYSMEM_REGIONS	4
 
 /* Definition of memblock flags. */
 #define MEMBLOCK_HOTPLUG	0x1	/* hotpluggable region */
@@ -43,6 +44,9 @@ struct memblock {
 	phys_addr_t current_limit;
 	struct memblock_type memory;
 	struct memblock_type reserved;
+#ifdef CONFIG_HAVE_MEMBLOCK_PHYS_MAP
+	struct memblock_type physmem;
+#endif
 };
 
 extern struct memblock memblock;

mm/Kconfig

@@ -134,6 +134,9 @@ config HAVE_MEMBLOCK
 config HAVE_MEMBLOCK_NODE_MAP
 	boolean
 
+config HAVE_MEMBLOCK_PHYS_MAP
+	boolean
+
 config ARCH_DISCARD_MEMBLOCK
 	boolean
 

mm/memblock.c

@@ -27,6 +27,9 @@
 
 static struct memblock_region memblock_memory_init_regions[INIT_MEMBLOCK_REGIONS] __initdata_memblock;
 static struct memblock_region memblock_reserved_init_regions[INIT_MEMBLOCK_REGIONS] __initdata_memblock;
+#ifdef CONFIG_HAVE_MEMBLOCK_PHYS_MAP
+static struct memblock_region memblock_physmem_init_regions[INIT_PHYSMEM_REGIONS] __initdata_memblock;
+#endif
 
 struct memblock memblock __initdata_memblock = {
 	.memory.regions		= memblock_memory_init_regions,
@@ -37,6 +40,12 @@ struct memblock memblock __initdata_memblock = {
 	.reserved.cnt		= 1,	/* empty dummy entry */
 	.reserved.max		= INIT_MEMBLOCK_REGIONS,
 
+#ifdef CONFIG_HAVE_MEMBLOCK_PHYS_MAP
+	.physmem.regions	= memblock_physmem_init_regions,
+	.physmem.cnt		= 1,	/* empty dummy entry */
+	.physmem.max		= INIT_PHYSMEM_REGIONS,
+#endif
+
 	.bottom_up		= false,
 	.current_limit		= MEMBLOCK_ALLOC_ANYWHERE,
 };
@@ -1553,6 +1562,9 @@ static int __init memblock_init_debugfs(void)
 		return -ENXIO;
 	debugfs_create_file("memory", S_IRUGO, root, &memblock.memory, &memblock_debug_fops);
 	debugfs_create_file("reserved", S_IRUGO, root, &memblock.reserved, &memblock_debug_fops);
+#ifdef CONFIG_HAVE_MEMBLOCK_PHYS_MAP
+	debugfs_create_file("physmem", S_IRUGO, root, &memblock.physmem, &memblock_debug_fops);
+#endif
 
 	return 0;
 }