mm/memblock: define memblock_physmem_add()

On the s390 platform memblock.physmem array is being built by directly
calling into memblock_add_range() which is a low level function not
intended to be used outside of memblock.  Hence lets conditionally add
helper functions for physmem array when HAVE_MEMBLOCK_PHYS_MAP is
enabled.  Also use MAX_NUMNODES instead of 0 as node ID similar to
memblock_add() and memblock_reserve().  Make memblock_add_range() a
static function as it is no longer getting used outside of memblock.

Link: http://lkml.kernel.org/r/1578283835-21969-1-git-send-email-anshuman.khandual@arm.com
Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com>
Reviewed-by: Mike Rapoport <rppt@linux.ibm.com>
Acked-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Collin Walling <walling@linux.ibm.com>
Cc: Gerald Schaefer <gerald.schaefer@de.ibm.com>
Cc: Philipp Rudo <prudo@linux.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/mm/memblock.c b/mm/memblock.c
index 4bc2c7d..fc0d4db 100644
--- a/mm/memblock.c
+++ b/mm/memblock.c
@@ -575,7 +575,7 @@ static void __init_memblock memblock_insert_region(struct memblock_type *type,
  * Return:
  * 0 on success, -errno on failure.
  */
-int __init_memblock memblock_add_range(struct memblock_type *type,
+static int __init_memblock memblock_add_range(struct memblock_type *type,
 				phys_addr_t base, phys_addr_t size,
 				int nid, enum memblock_flags flags)
 {
@@ -830,6 +830,18 @@ int __init_memblock memblock_reserve(phys_addr_t base, phys_addr_t size)
 	return memblock_add_range(&memblock.reserved, base, size, MAX_NUMNODES, 0);
 }
 
+#ifdef CONFIG_HAVE_MEMBLOCK_PHYS_MAP
+int __init_memblock memblock_physmem_add(phys_addr_t base, phys_addr_t size)
+{
+	phys_addr_t end = base + size - 1;
+
+	memblock_dbg("%s: [%pa-%pa] %pS\n", __func__,
+		     &base, &end, (void *)_RET_IP_);
+
+	return memblock_add_range(&memblock.physmem, base, size, MAX_NUMNODES, 0);
+}
+#endif
+
 /**
  * memblock_setclr_flag - set or clear flag for a memory region
  * @base: base address of the region