[RFC PATCH 4/4] arm64:numa: adding numa support for arm64 platforms.

@@ -142,6 +142,7 @@ config ARCH_THUNDER
 	select NET_VENDOR_CAVIUM
 	select SATA_AHCI
 	select SATA_AHCI_PLATFORM
+	select HAVE_MEMBLOCK_NODE_MAP if NUMA
 
 config ARCH_VEXPRESS
 	bool "ARMv8 software model (Versatile Express)"

@@ -309,6 +310,38 @@ config HOTPLUG_CPU
 	  Say Y here to experiment with turning CPUs off and on.  CPUs
 	  can be controlled through /sys/devices/system/cpu.
 
+# Common NUMA Features
+config NUMA
+	bool "Numa Memory Allocation and Scheduler Support"
+	depends on SMP
+	---help---
+	  Enable NUMA (Non Uniform Memory Access) support.
+
+	  The kernel will try to allocate memory used by a CPU on the
+	  local memory controller of the CPU and add some more
+	  NUMA awareness to the kernel.
+
+config ARM64_DT_NUMA
+	def_bool y
+	prompt "DT NUMA detection"
+	depends on ARM64 && NUMA && DTC
+	---help---
+	  Enable DT based numa.
+
+config NODES_SHIFT
+	int "Maximum NUMA Nodes (as a power of 2)"
+	range 1 10
+	default "2"
+	depends on NEED_MULTIPLE_NODES
+	---help---
+	  Specify the maximum number of NUMA Nodes available on the target
+	  system.  Increases memory reserved to accommodate various tables.
+
+config USE_PERCPU_NUMA_NODE_ID
+	def_bool y
+	depends on NUMA
+
+
 source kernel/Kconfig.preempt
 
 config HZ

@@ -0,0 +1,32 @@
+#ifndef __ASM_ARM64_MMZONE_H_
+#define __ASM_ARM64_MMZONE_H_
+
+#ifdef CONFIG_NUMA
+
+#include <linux/mmdebug.h>
+#include <asm/smp.h>
+#include <linux/types.h>
+#include <asm/numa.h>
+
+extern struct pglist_data *node_data[];
+
+#define NODE_DATA(nid)		(node_data[nid])
+
+
+struct numa_memblk {
+	u64			start;
+	u64			end;
+	int			nid;
+};
+
+struct numa_meminfo {
+	int			nr_blks;
+	struct numa_memblk	blk[NR_NODE_MEMBLKS];
+};
+
+void __init numa_remove_memblk_from(int idx, struct numa_meminfo *mi);
+int __init numa_cleanup_meminfo(struct numa_meminfo *mi);
+void __init numa_reset_distance(void);
+
+#endif /* CONFIG_NUMA */
+#endif /* __ASM_ARM64_MMZONE_H_ */

@@ -0,0 +1,41 @@
+#ifndef _ASM_ARM64_NUMA_H
+#define _ASM_ARM64_NUMA_H
+
+#include <linux/nodemask.h>
+#include <asm/topology.h>
+
+#ifdef CONFIG_NUMA
+
+#define NR_NODE_MEMBLKS		(MAX_NUMNODES * 2)
+#define ZONE_ALIGN (1UL << (MAX_ORDER + PAGE_SHIFT))
+
+/*
+ * Too small node sizes may confuse the VM badly. Usually they
+ * result from BIOS bugs. So dont recognize nodes as standalone
+ * NUMA entities that have less than this amount of RAM listed:
+ */
+#define NODE_MIN_SIZE (4*1024*1024)
+
+#define parent_node(node)	(node)
+
+/* dummy definitions for pci functions */
+#define pcibus_to_node(node)	0
+#define cpumask_of_pcibus(bus)	0
+
+const struct cpumask *cpumask_of_node(int node);
+/* Mappings between node number and cpus on that node. */
+extern cpumask_var_t node_to_cpumask_map[MAX_NUMNODES];
+
+void __init arm64_numa_init(void);
+int __init numa_add_memblk(u32 nodeid, u64 start, u64 end);
+void numa_store_cpu_info(int cpu);
+void numa_set_node(int cpu, int node);
+void numa_clear_node(int cpu);
+void numa_add_cpu(int cpu);
+void numa_remove_cpu(int cpu);
+#else	/* CONFIG_NUMA */
+static inline void arm64_numa_init(void);
+static inline void numa_store_cpu_info(int cpu)	{ }
+static inline void arm64_numa_init()			{ }
+#endif	/* CONFIG_NUMA */
+#endif	/* _ASM_ARM64_NUMA_H */

@@ -424,6 +424,9 @@ static int __init topology_init(void)
 {
 	int i;
 
+	for_each_online_node(i)
+		register_one_node(i);
+
 	for_each_possible_cpu(i) {
 		struct cpu *cpu = &per_cpu(cpu_data.cpu, i);
 		cpu->hotpluggable = 1;

@@ -460,7 +463,12 @@ static int c_show(struct seq_file *m, void *v)
 		 * "processor".  Give glibc what it expects.
 		 */
 #ifdef CONFIG_SMP
+	if (IS_ENABLED(CONFIG_NUMA)) {
+		seq_printf(m, "processor\t: %d", i);
+		seq_printf(m, " [nid: %d]\n", cpu_to_node(i));
+	} else {
 		seq_printf(m, "processor\t: %d\n", i);
+	}
 #endif
 	}
 

@@ -50,6 +50,7 @@
 #include <asm/sections.h>
 #include <asm/tlbflush.h>
 #include <asm/ptrace.h>
+#include <asm/numa.h>
 
 #define CREATE_TRACE_POINTS
 #include <trace/events/ipi.h>

@@ -123,6 +124,7 @@ int __cpu_up(unsigned int cpu, struct task_struct *idle)
 static void smp_store_cpu_info(unsigned int cpuid)
 {
 	store_cpu_topology(cpuid);
+	numa_store_cpu_info(cpuid);
 }
 
 /*

@@ -3,3 +3,4 @@ obj-y				:= dma-mapping.o extable.o fault.o init.o \
 				   ioremap.o mmap.o pgd.o mmu.o \
 				   context.o proc.o
 obj-$(CONFIG_HUGETLB_PAGE)	+= hugetlbpage.o
+obj-$(CONFIG_NUMA)		+= numa.o

@@ -39,6 +39,7 @@
 #include <asm/setup.h>
 #include <asm/sizes.h>
 #include <asm/tlb.h>
+#include <asm/numa.h>
 
 #include "mm.h"
 

@@ -73,6 +74,20 @@ static phys_addr_t max_zone_dma_phys(void)
 	return min(offset + (1ULL << 32), memblock_end_of_DRAM());
 }
 
+#ifdef CONFIG_NUMA
+static void __init zone_sizes_init(unsigned long min, unsigned long max)
+{
+	unsigned long max_zone_pfns[MAX_NR_ZONES];
+
+	memset(max_zone_pfns, 0, sizeof(max_zone_pfns));
+	if (IS_ENABLED(CONFIG_ZONE_DMA))
+		max_zone_pfns[ZONE_DMA] = PFN_DOWN(max_zone_dma_phys());
+	max_zone_pfns[ZONE_NORMAL] = max;
+
+	free_area_init_nodes(max_zone_pfns);
+}
+
+#else
 static void __init zone_sizes_init(unsigned long min, unsigned long max)
 {
 	struct memblock_region *reg;

@@ -111,6 +126,7 @@ static void __init zone_sizes_init(unsigned long min, unsigned long max)
 
 	free_area_init_node(0, zone_size, min, zhole_size);
 }
+#endif /* CONFIG_NUMA */
 
 #ifdef CONFIG_HAVE_ARCH_PFN_VALID
 int pfn_valid(unsigned long pfn)

@@ -129,9 +145,16 @@ static void arm64_memory_present(void)
 {
 	struct memblock_region *reg;
 
-	for_each_memblock(memory, reg)
+	for_each_memblock(memory, reg) {
+#ifdef CONFIG_NUMA
+		memory_present(reg->nid,
+				memblock_region_memory_base_pfn(reg),
+				memblock_region_memory_end_pfn(reg));
+#else
 		memory_present(0, memblock_region_memory_base_pfn(reg),
 			       memblock_region_memory_end_pfn(reg));
+#endif
+	}
 }
 #endif
 

@@ -168,6 +191,11 @@ void __init bootmem_init(void)
 	min = PFN_UP(memblock_start_of_DRAM());
 	max = PFN_DOWN(memblock_end_of_DRAM());
 
+	high_memory = __va((max << PAGE_SHIFT) - 1) + 1;
+	max_pfn = max_low_pfn = max;
+
+	if (IS_ENABLED(CONFIG_NUMA))
+		arm64_numa_init();
 	/*
 	 * Sparsemem tries to allocate bootmem in memory_present(), so must be
 	 * done after the fixed reservations.

@@ -176,9 +204,6 @@ void __init bootmem_init(void)
 
 	sparse_init();
 	zone_sizes_init(min, max);
-
-	high_memory = __va((max << PAGE_SHIFT) - 1) + 1;
-	max_pfn = max_low_pfn = max;
 }
 
 #ifndef CONFIG_SPARSEMEM_VMEMMAP

@@ -0,0 +1,469 @@
+/*
+ * NUMA support, based on the x86 implementation.
+ *
+ * Copyright (C) 2014 Cavium Inc.
+ * Author: Ganapatrao Kulkarni <gkulkarni@cavium.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <linux/kernel.h>
+#include <linux/mm.h>
+#include <linux/string.h>
+#include <linux/init.h>
+#include <linux/bootmem.h>
+#include <linux/memblock.h>
+#include <linux/mmzone.h>
+#include <linux/ctype.h>
+#include <linux/module.h>
+#include <linux/nodemask.h>
+#include <linux/sched.h>
+#include <linux/topology.h>
+#include <linux/of.h>
+#include <linux/of_fdt.h>
+
+int __initdata numa_off;
+nodemask_t numa_nodes_parsed __initdata;
+
+struct pglist_data *node_data[MAX_NUMNODES] __read_mostly;
+EXPORT_SYMBOL(node_data);
+
+static struct numa_meminfo numa_meminfo;
+
+static __init int numa_setup(char *opt)
+{
+	if (!opt)
+		return -EINVAL;
+	if (!strncmp(opt, "off", 3))
+		numa_off = 1;
+	return 0;
+}
+early_param("numa", numa_setup);
+
+cpumask_var_t node_to_cpumask_map[MAX_NUMNODES];
+EXPORT_SYMBOL(node_to_cpumask_map);
+
+/*
+ * Returns a pointer to the bitmask of CPUs on Node 'node'.
+ */
+const struct cpumask *cpumask_of_node(int node)
+{
+	if (node >= nr_node_ids) {
+		pr_warn("cpumask_of_node(%d): node > nr_node_ids(%d)\n",
+			node, nr_node_ids);
+		dump_stack();
+		return cpu_none_mask;
+	}
+	if (node_to_cpumask_map[node] == NULL) {
+		pr_warn("cpumask_of_node(%d): no node_to_cpumask_map!\n",
+			node);
+		dump_stack();
+		return cpu_online_mask;
+	}
+	return node_to_cpumask_map[node];
+}
+EXPORT_SYMBOL(cpumask_of_node);
+
+int cpu_to_node_map[NR_CPUS];
+EXPORT_SYMBOL(cpu_to_node_map);
+
+void numa_clear_node(int cpu)
+{
+	cpu_to_node_map[cpu] = NUMA_NO_NODE;
+}
+
+/*
+ * Allocate node_to_cpumask_map based on number of available nodes
+ * Requires node_possible_map to be valid.
+ *
+ * Note: cpumask_of_node() is not valid until after this is done.
+ * (Use CONFIG_DEBUG_PER_CPU_MAPS to check this.)
+ */
+void __init setup_node_to_cpumask_map(void)
+{
+	unsigned int node;
+
+	/* setup nr_node_ids if not done yet */
+	if (nr_node_ids == MAX_NUMNODES)
+		setup_nr_node_ids();
+
+	/* allocate the map */
+	for (node = 0; node < nr_node_ids; node++)
+		alloc_bootmem_cpumask_var(&node_to_cpumask_map[node]);
+
+	/* cpumask_of_node() will now work */
+	pr_debug("Node to cpumask map for %d nodes\n", nr_node_ids);
+}
+
+/*
+ *  Set the cpu to node and mem mapping
+ */
+void numa_store_cpu_info(cpu)
+{
+	cpu_to_node_map[cpu] = cpu_topology[cpu].cluster_id;
+	cpumask_set_cpu(cpu, node_to_cpumask_map[cpu_to_node_map[cpu]]);
+	set_numa_node(cpu_to_node_map[cpu]);
+	set_numa_mem(local_memory_node(cpu_to_node_map[cpu]));
+}
+
+/**
+ * numa_add_memblk_to - Add one numa_memblk to a numa_meminfo
+ */
+
+static int __init numa_add_memblk_to(int nid, u64 start, u64 end,
+				     struct numa_meminfo *mi)
+{
+	/* ignore zero length blks */
+	if (start == end)
+		return 0;
+
+	/* whine about and ignore invalid blks */
+	if (start > end || nid < 0 || nid >= MAX_NUMNODES) {
+		pr_warn("numa: Warning: invalid memblk node %d [mem %#010Lx-%#010Lx]\n",
+				nid, start, end - 1);
+		return 0;
+	}
+
+	if (mi->nr_blks >= NR_NODE_MEMBLKS) {
+		pr_err("numa: too many memblk ranges\n");
+		return -EINVAL;
+	}
+
+	pr_info("numa: Adding memblock %d [0x%llx - 0x%llx] on node %d\n",
+			mi->nr_blks, start, end, nid);
+	mi->blk[mi->nr_blks].start = start;
+	mi->blk[mi->nr_blks].end = end;
+	mi->blk[mi->nr_blks].nid = nid;
+	mi->nr_blks++;
+	return 0;
+}
+
+/**
+ * numa_add_memblk - Add one numa_memblk to numa_meminfo
+ * @nid: NUMA node ID of the new memblk
+ * @start: Start address of the new memblk
+ * @end: End address of the new memblk
+ *
+ * Add a new memblk to the default numa_meminfo.
+ *
+ * RETURNS:
+ * 0 on success, -errno on failure.
+ */
+#define MAX_PHYS_ADDR	((phys_addr_t)~0)
+
+int __init numa_add_memblk(u32 nid, u64 base, u64 size)
+{
+	const u64 phys_offset = __pa(PAGE_OFFSET);
+
+	base &= PAGE_MASK;
+	size &= PAGE_MASK;
+
+	if (base > MAX_PHYS_ADDR) {
+		pr_warn("numa: Ignoring memory block 0x%llx - 0x%llx\n",
+				base, base + size);
+		return -ENOMEM;
+	}
+
+	if (base + size > MAX_PHYS_ADDR) {
+		pr_warn("numa: Ignoring memory range 0x%lx - 0x%llx\n",
+				ULONG_MAX, base + size);
+		size = MAX_PHYS_ADDR - base;
+	}
+
+	if (base + size < phys_offset) {
+		pr_warn("numa: Ignoring memory block 0x%llx - 0x%llx\n",
+			   base, base + size);
+		return -ENOMEM;
+	}
+	if (base < phys_offset) {
+		pr_warn("numa: Ignoring memory range 0x%llx - 0x%llx\n",
+			   base, phys_offset);
+		size -= phys_offset - base;
+		base = phys_offset;
+	}
+
+	node_set(nid, numa_nodes_parsed);
+	return numa_add_memblk_to(nid, base, base+size, &numa_meminfo);
+}
+EXPORT_SYMBOL(numa_add_memblk);
+
+/* Initialize NODE_DATA for a node on the local memory */
+static void __init setup_node_data(int nid, u64 start, u64 end)
+{
+	const size_t nd_size = roundup(sizeof(pg_data_t), PAGE_SIZE);
+	u64 nd_pa;
+	void *nd;
+	int tnid;
+
+	/*
+	 * Don't confuse VM with a node that doesn't have the
+	 * minimum amount of memory:
+	 */
+	if (end && (end - start) < NODE_MIN_SIZE)
+		return;
+
+	start = roundup(start, ZONE_ALIGN);
+
+	pr_info("Initmem setup node %d [mem %#010Lx-%#010Lx]\n",
+	       nid, start, end - 1);
+
+	/*
+	 * Allocate node data.  Try node-local memory and then any node.
+	 */
+	nd_pa = memblock_alloc_nid(nd_size, SMP_CACHE_BYTES, nid);
+	if (!nd_pa) {
+		nd_pa = __memblock_alloc_base(nd_size, SMP_CACHE_BYTES,
+					      MEMBLOCK_ALLOC_ACCESSIBLE);
+		if (!nd_pa) {
+			pr_err("Cannot find %zu bytes in node %d\n",
+			       nd_size, nid);
+			return;
+		}
+	}
+	nd = __va(nd_pa);
+
+	/* report and initialize */
+	pr_info("  NODE_DATA [mem %#010Lx-%#010Lx]\n",
+	       nd_pa, nd_pa + nd_size - 1);
+	tnid = early_pfn_to_nid(nd_pa >> PAGE_SHIFT);
+	if (tnid != nid)
+		pr_info("    NODE_DATA(%d) on node %d\n", nid, tnid);
+
+	node_data[nid] = nd;
+	memset(NODE_DATA(nid), 0, sizeof(pg_data_t));
+	NODE_DATA(nid)->node_id = nid;
+	NODE_DATA(nid)->node_start_pfn = start >> PAGE_SHIFT;
+	NODE_DATA(nid)->node_spanned_pages = (end - start) >> PAGE_SHIFT;
+
+	node_set_online(nid);
+}
+
+/*
+ * Set nodes, which have memory in @mi, in *@nodemask.
+ */
+static void __init numa_nodemask_from_meminfo(nodemask_t *nodemask,
+					      const struct numa_meminfo *mi)
+{
+	int i;
+
+	for (i = 0; i < ARRAY_SIZE(mi->blk); i++)
+		if (mi->blk[i].start != mi->blk[i].end &&
+		    mi->blk[i].nid != NUMA_NO_NODE)
+			node_set(mi->blk[i].nid, *nodemask);
+}
+
+/*
+ * Sanity check to catch more bad NUMA configurations (they are amazingly
+ * common).  Make sure the nodes cover all memory.
+ */
+static bool __init numa_meminfo_cover_memory(const struct numa_meminfo *mi)
+{
+	u64 numaram, totalram;
+	int i;
+
+	numaram = 0;
+	for (i = 0; i < mi->nr_blks; i++) {
+		u64 s = mi->blk[i].start >> PAGE_SHIFT;
+		u64 e = mi->blk[i].end >> PAGE_SHIFT;
+
+		numaram += e - s;
+		numaram -= __absent_pages_in_range(mi->blk[i].nid, s, e);
+		if ((s64)numaram < 0)
+			numaram = 0;
+	}
+
+	totalram = max_pfn - absent_pages_in_range(0, max_pfn);
+
+	/* We seem to lose 3 pages somewhere. Allow 1M of slack. */
+	if ((s64)(totalram - numaram) >= (1 << (20 - PAGE_SHIFT))) {
+		pr_err("numa: nodes only cover %lluMB of your %lluMB Total RAM. Not used.\n",
+		       (numaram << PAGE_SHIFT) >> 20,
+		       (totalram << PAGE_SHIFT) >> 20);
+		return false;
+	}
+	return true;
+}
+
+static int __init numa_register_memblks(struct numa_meminfo *mi)
+{
+	unsigned long uninitialized_var(pfn_align);
+	int i, nid;
+
+	/* Account for nodes with cpus and no memory */
+	node_possible_map = numa_nodes_parsed;
+	numa_nodemask_from_meminfo(&node_possible_map, mi);
+	if (WARN_ON(nodes_empty(node_possible_map)))
+		return -EINVAL;
+
+	for (i = 0; i < mi->nr_blks; i++) {
+		struct numa_memblk *mb = &mi->blk[i];
+
+		memblock_set_node(mb->start, mb->end - mb->start,
+				  &memblock.memory, mb->nid);
+	}
+
+	/*
+	 * If sections array is gonna be used for pfn -> nid mapping, check
+	 * whether its granularity is fine enough.
+	 */
+#ifdef NODE_NOT_IN_PAGE_FLAGS
+	pfn_align = node_map_pfn_alignment();
+	if (pfn_align && pfn_align < PAGES_PER_SECTION) {
+		pr_warn("Node alignment %lluMB < min %lluMB, rejecting NUMA config\n",
+		       PFN_PHYS(pfn_align) >> 20,
+		       PFN_PHYS(PAGES_PER_SECTION) >> 20);
+		return -EINVAL;
+	}
+#endif
+	if (!numa_meminfo_cover_memory(mi))
+		return -EINVAL;
+
+	/* Finally register nodes. */
+	for_each_node_mask(nid, node_possible_map) {
+		u64 start = PFN_PHYS(max_pfn);
+		u64 end = 0;
+
+		for (i = 0; i < mi->nr_blks; i++) {
+			if (nid != mi->blk[i].nid)
+				continue;
+			start = min(mi->blk[i].start, start);
+			end = max(mi->blk[i].end, end);
+		}
+
+		if (start < end)
+			setup_node_data(nid, start, end);
+	}
+
+	/* Dump memblock with node info and return. */
+	memblock_dump_all();
+	return 0;
+}
+
+static int __init numa_init(int (*init_func)(void))
+{
+	int ret, i;
+
+	nodes_clear(node_possible_map);
+	nodes_clear(node_online_map);
+
+	ret = init_func();
+	if (ret < 0)
+		return ret;
+
+	ret = numa_register_memblks(&numa_meminfo);
+	if (ret < 0)
+		return ret;
+
+	for (i = 0; i < nr_cpu_ids; i++)
+		numa_clear_node(i);
+
+	setup_node_to_cpumask_map();
+	return 0;
+}
+
+/**
+ * dummy_numa_init - Fallback dummy NUMA init
+ *
+ * Used if there's no underlying NUMA architecture, NUMA initialization
+ * fails, or NUMA is disabled on the command line.
+ *
+ * Must online at least one node and add memory blocks that cover all
+ * allowed memory.  This function must not fail.
+ */
+static int __init dummy_numa_init(void)
+{
+	pr_info("%s\n",
+	       numa_off ? "NUMA turned off" : "No NUMA configuration found");
+	pr_info("Faking a node at [mem %#018Lx-%#018Lx]\n",
+	       0LLU, PFN_PHYS(max_pfn) - 1);
+
+	node_set(0, numa_nodes_parsed);
+	numa_add_memblk(0, 0, PFN_PHYS(max_pfn));
+
+	return 0;
+}
+
+/**
+ * early_init_dt_scan_numa_map - parse memory node and map nid to memory range.
+ */
+int __init early_init_dt_scan_numa_map(unsigned long node, const char *uname,
+				     int depth, void *data)
+{
+	const char *type = of_get_flat_dt_prop(node, "device_type", NULL);
+	const __be32 *reg, *endp, *nid_prop;
+	int l, nid;
+
+	/* We are scanning "memory" nodes only */
+	if (type == NULL) {
+		/*
+		 * The longtrail doesn't have a device_type on the
+		 * /memory node, so look for the node called /memory at 0.
+		 */
+		if (depth != 1 || strcmp(uname, "memory@0") != 0)
+			return 0;
+	} else if (strcmp(type, "memory") != 0)
+		return 0;
+
+	reg = of_get_flat_dt_prop(node, "reg", &l);
+	if (reg == NULL)
+		return 0;
+
+	endp = reg + (l / sizeof(__be32));
+	nid_prop = of_get_flat_dt_prop(node, "nid", &l);
+
+	if (nid_prop == NULL)
+		return -1;
+
+	nid = dt_mem_next_cell(OF_ROOT_NODE_ADDR_CELLS_DEFAULT, &nid_prop);
+
+	while ((endp - reg) >= (dt_root_addr_cells + dt_root_size_cells)) {
+		u64 base, size;
+
+		base = dt_mem_next_cell(dt_root_addr_cells, &reg);
+		size = dt_mem_next_cell(dt_root_size_cells, &reg);
+
+		if (size == 0)
+			continue;
+		pr_debug("numa: nid %d , base %llx , size %llx\n", nid,
+				(unsigned long long)base,
+				(unsigned long long)size);
+		numa_add_memblk(nid, base, size);
+	}
+	return 0;
+}
+
+/* DT node mapping is done already early_init_dt_scan_memory */
+static inline int __init arm64_dt_numa_init(void)
+{
+	of_scan_flat_dt(early_init_dt_scan_numa_map, NULL);
+	return 0;
+}
+
+/**
+ * arm64_numa_init - Initialize NUMA
+ *
+ * Try each configured NUMA initialization method until one succeeds.  The
+ * last fallback is dummy single node config encomapssing whole memory and
+ * never fails.
+ */
+void __init arm64_numa_init(void)
+{
+	if (!numa_off) {
+#ifdef CONFIG_ARM64_DT_NUMA
+		if (!numa_init(arm64_dt_numa_init))
+			return;
+#endif
+	}
+
+	numa_init(dummy_numa_init);
+}