diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
index 09ce0b34b18c7fd673b9c2d69845f27c1be09b98..9f8b65407eee23693c2d4022259c6fd2aa55032a 100644
--- a/arch/arm64/Kconfig
+++ b/arch/arm64/Kconfig
@@ -257,6 +257,9 @@ config ZONE_DMA32
 config HAVE_GENERIC_GUP
 	def_bool y
 
+config ARCH_ENABLE_MEMORY_HOTPLUG
+	def_bool y
+
 config SMP
 	def_bool y
 
diff --git a/arch/arm64/mm/init.c b/arch/arm64/mm/init.c
index 9985df83919030a1338ebbf552b148c9882816fe..7b6278bcc87b5cbf77f7da650c56f55a39e1bb71 100644
--- a/arch/arm64/mm/init.c
+++ b/arch/arm64/mm/init.c
@@ -291,6 +291,14 @@ int pfn_valid(unsigned long pfn)
 
 	if ((addr >> PAGE_SHIFT) != pfn)
 		return 0;
+
+#ifdef CONFIG_SPARSEMEM
+	if (pfn_to_section_nr(pfn) >= NR_MEM_SECTIONS)
+		return 0;
+
+	if (!valid_section(__nr_to_section(pfn_to_section_nr(pfn))))
+		return 0;
+#endif
 	return memblock_is_map_memory(addr);
 }
 EXPORT_SYMBOL(pfn_valid);
diff --git a/arch/arm64/mm/mmu.c b/arch/arm64/mm/mmu.c
index cad24a2551fd29e840fa02ce3099a83ecaf87e28..33eef39658e80602118ee140fad1bab265cd8952 100644
--- a/arch/arm64/mm/mmu.c
+++ b/arch/arm64/mm/mmu.c
@@ -1030,3 +1030,20 @@ int pud_free_pmd_page(pud_t *pudp, unsigned long addr)
 	pmd_free(NULL, table);
 	return 1;
 }
+
+#ifdef CONFIG_MEMORY_HOTPLUG
+int arch_add_memory(int nid, u64 start, u64 size, struct vmem_altmap *altmap,
+		    bool want_memblock)
+{
+	int flags = 0;
+
+	if (debug_pagealloc_enabled())
+		flags = NO_BLOCK_MAPPINGS | NO_CONT_MAPPINGS;
+
+	__create_pgd_mapping(swapper_pg_dir, start, __phys_to_virt(start),
+			     size, PAGE_KERNEL, pgd_pgtable_alloc, flags);
+
+	return __add_pages(nid, start >> PAGE_SHIFT, size >> PAGE_SHIFT,
+			   altmap, want_memblock);
+}
+#endif
diff --git a/arch/arm64/mm/numa.c b/arch/arm64/mm/numa.c
index 146c04ceaa514bace2f7aaa49936ca5ca8865741..d276bd4d38b588aa111ad32406a2c54563791d93 100644
--- a/arch/arm64/mm/numa.c
+++ b/arch/arm64/mm/numa.c
@@ -464,3 +464,13 @@ void __init arm64_numa_init(void)
 
 	numa_init(dummy_numa_init);
 }
+
+/*
+ * We hope that we will be hotplugging memory on nodes we already know about,
+ * such that acpi_get_node() succeeds and we never fall back to this...
+ */
+int memory_add_physaddr_to_nid(u64 addr)
+{
+	pr_warn("Unknown node for memory at 0x%llx, assuming node 0\n", addr);
+	return 0;
+}