diff --git a/arch/arm64/kernel/setup.c b/arch/arm64/kernel/setup.c
index 4a5f6243ade26cd9ca34a0e6cdd7f280869c5bad..7feb0c97d0dd0faf9b2ab2fbea569b4fae8c7af9 100644
--- a/arch/arm64/kernel/setup.c
+++ b/arch/arm64/kernel/setup.c
@@ -147,24 +147,6 @@ static void __init setup_machine_fdt(phys_addr_t dt_phys)
 	pr_info("Machine: %s\n", machine_name);
 }
 
-void __init early_init_dt_add_memory_arch(u64 base, u64 size)
-{
-	base &= PAGE_MASK;
-	size &= PAGE_MASK;
-	if (base + size < PHYS_OFFSET) {
-		pr_warning("Ignoring memory block 0x%llx - 0x%llx\n",
-			   base, base + size);
-		return;
-	}
-	if (base < PHYS_OFFSET) {
-		pr_warning("Ignoring memory range 0x%llx - 0x%llx\n",
-			   base, PHYS_OFFSET);
-		size -= PHYS_OFFSET - base;
-		base = PHYS_OFFSET;
-	}
-	memblock_add(base, size);
-}
-
 /*
  * Limit the memory size that was specified via FDT.
  */
diff --git a/arch/microblaze/kernel/prom.c b/arch/microblaze/kernel/prom.c
index e13686ede3301ea3b222eff32fde70f4a413823e..951e4d61ca2dc26bc40e934b13f79af9df65ae6b 100644
--- a/arch/microblaze/kernel/prom.c
+++ b/arch/microblaze/kernel/prom.c
@@ -41,11 +41,6 @@
 #include <asm/sections.h>
 #include <asm/pci-bridge.h>
 
-void __init early_init_dt_add_memory_arch(u64 base, u64 size)
-{
-	memblock_add(base, size);
-}
-
 #ifdef CONFIG_EARLY_PRINTK
 static char *stdout;
 
diff --git a/arch/openrisc/kernel/prom.c b/arch/openrisc/kernel/prom.c
index fbed459ea36547af8b1a8223d06c5a3277b6f383..6dbcaa85421ce3d5c61806c30b586ab082b4ff84 100644
--- a/arch/openrisc/kernel/prom.c
+++ b/arch/openrisc/kernel/prom.c
@@ -47,12 +47,6 @@
 #include <asm/sections.h>
 #include <asm/setup.h>
 
-void __init early_init_dt_add_memory_arch(u64 base, u64 size)
-{
-	size &= PAGE_MASK;
-	memblock_add(base, size);
-}
-
 void __init early_init_devtree(void *params)
 {
 	early_init_dt_scan(params);
diff --git a/drivers/of/fdt.c b/drivers/of/fdt.c
index bfbfda5437682c54a79e76cbb3cbacbbe0f43bd7..5bc55b6e2b41e9afa791ea576527e0aa77f3f795 100644
--- a/drivers/of/fdt.c
+++ b/drivers/of/fdt.c
@@ -775,6 +775,25 @@ int __init early_init_dt_scan_chosen(unsigned long node, const char *uname,
 }
 
 #ifdef CONFIG_HAVE_MEMBLOCK
+void __init __weak early_init_dt_add_memory_arch(u64 base, u64 size)
+{
+	const u64 phys_offset = __pa(PAGE_OFFSET);
+	base &= PAGE_MASK;
+	size &= PAGE_MASK;
+	if (base + size < phys_offset) {
+		pr_warning("Ignoring memory block 0x%llx - 0x%llx\n",
+			   base, base + size);
+		return;
+	}
+	if (base < phys_offset) {
+		pr_warning("Ignoring memory range 0x%llx - 0x%llx\n",
+			   base, phys_offset);
+		size -= phys_offset - base;
+		base = phys_offset;
+	}
+	memblock_add(base, size);
+}
+
 /*
  * called from unflatten_device_tree() to bootstrap devicetree itself
  * Architectures can override this definition if memblock isn't used