[Arm-dev] [PATCH v0 15/20] arm64:numa: adding numa support for arm64 platforms.

Thu Jul 23 12:37:52 UTC 2015
Vadim Lomovtsev <Vadim.Lomovtsev at caviumnetworks.com>

From: Ganapatrao Kulkarni <gkulkarni at caviumnetworks.com>

Adding numa support for arm64 based platforms.
The memory to node mapping is derived either from dt and acpi based memory tables.

Signed-off-by: Ganapatrao Kulkarni <gkulkarni at caviumnetworks.com>
Signed-off-by: Vadim Lomovtsev <Vadim.Lomovtsev at caviumnetworks.com>

Conflicts:
	arch/arm64/mm/init.c
---
 arch/arm64/Kconfig              |  32 +++
 arch/arm64/include/asm/mmzone.h |  32 +++
 arch/arm64/include/asm/numa.h   |  43 ++++
 arch/arm64/kernel/setup.c       |   8 +
 arch/arm64/kernel/smp.c         |   2 +
 arch/arm64/mm/Makefile          |   1 +
 arch/arm64/mm/init.c            |  34 ++-
 arch/arm64/mm/numa.c            | 522 ++++++++++++++++++++++++++++++++++++++++
 8 files changed, 668 insertions(+), 6 deletions(-)
 create mode 100644 arch/arm64/include/asm/mmzone.h
 create mode 100644 arch/arm64/include/asm/numa.h
 create mode 100644 arch/arm64/mm/numa.c

diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
index 2c542d5..7302706 100644
--- a/arch/arm64/Kconfig
+++ b/arch/arm64/Kconfig
@@ -72,6 +72,7 @@ config ARM64
 	select HAVE_PERF_USER_STACK_DUMP
 	select HAVE_RCU_TABLE_FREE
 	select HAVE_SYSCALL_TRACEPOINTS
+	select HAVE_MEMBLOCK_NODE_MAP if NUMA
 	select IRQ_DOMAIN
 	select IRQ_FORCED_THREADING
 	select MODULES_USE_ELF_RELA
@@ -543,6 +544,37 @@ 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 n
+	prompt "DT NUMA detection"
+	---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 UP_LATE_INIT
diff --git a/arch/arm64/include/asm/mmzone.h b/arch/arm64/include/asm/mmzone.h
new file mode 100644
index 0000000..d27ee66
--- /dev/null
+++ b/arch/arm64/include/asm/mmzone.h
@@ -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_ */
diff --git a/arch/arm64/include/asm/numa.h b/arch/arm64/include/asm/numa.h
new file mode 100644
index 0000000..8be5cb1
--- /dev/null
+++ b/arch/arm64/include/asm/numa.h
@@ -0,0 +1,43 @@
+#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))
+
+/* currently, arm64 implements flat NUMA topology */
+#define parent_node(node)	(node)
+
+/* dummy definitions for pci functions */
+#define pcibus_to_node(node)	0
+#define cpumask_of_pcibus(bus)	0
+
+struct __node_cpu_hwid {
+	u32 node_id;    /* logical node containing this CPU */
+	u64 cpu_hwid;   /* MPIDR for this CPU */
+};
+
+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);
+void __init numa_set_distance(int from, int to, int distance);
+int dt_get_cpu_node_id(int cpu);
+int __init arm64_dt_numa_init(void);
+#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(void)		{ }
+#endif	/* CONFIG_NUMA */
+#endif	/* _ASM_ARM64_NUMA_H */
diff --git a/arch/arm64/kernel/setup.c b/arch/arm64/kernel/setup.c
index f3067d4..de22045 100644
--- a/arch/arm64/kernel/setup.c
+++ b/arch/arm64/kernel/setup.c
@@ -437,6 +437,9 @@ 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;
@@ -509,7 +512,12 @@ 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
 
 		/*
diff --git a/arch/arm64/kernel/smp.c b/arch/arm64/kernel/smp.c
index 50fb469..ae3e02c 100644
--- a/arch/arm64/kernel/smp.c
+++ b/arch/arm64/kernel/smp.c
@@ -52,6 +52,7 @@
 #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>
@@ -124,6 +125,7 @@ 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);
 }
 
 /*
diff --git a/arch/arm64/mm/Makefile b/arch/arm64/mm/Makefile
index 773d37a..bb92d41 100644
--- a/arch/arm64/mm/Makefile
+++ b/arch/arm64/mm/Makefile
@@ -4,3 +4,4 @@ obj-y				:= dma-mapping.o extable.o fault.o init.o \
 				   context.o proc.o pageattr.o
 obj-$(CONFIG_HUGETLB_PAGE)	+= hugetlbpage.o
 obj-$(CONFIG_ARM64_PTDUMP)	+= dump.o
+obj-$(CONFIG_NUMA)		+= numa.o
diff --git a/arch/arm64/mm/init.c b/arch/arm64/mm/init.c
index ad87ce8..dc28705 100644
--- a/arch/arm64/mm/init.c
+++ b/arch/arm64/mm/init.c
@@ -42,6 +42,7 @@
 #include <asm/sizes.h>
 #include <asm/tlb.h>
 #include <asm/alternative.h>
+#include <asm/numa.h>
 
 #include "mm.h"
 
@@ -77,6 +78,20 @@ 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;
@@ -115,6 +130,7 @@ 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)
@@ -132,10 +148,15 @@ static void arm64_memory_present(void)
 static void arm64_memory_present(void)
 {
 	struct memblock_region *reg;
+	int nid = 0;
 
-	for_each_memblock(memory, reg)
-		memory_present(0, memblock_region_memory_base_pfn(reg),
-			       memblock_region_memory_end_pfn(reg));
+	for_each_memblock(memory, reg) {
+#ifdef CONFIG_NUMA
+		nid = reg->nid;
+#endif
+		memory_present(nid, memblock_region_memory_base_pfn(reg),
+				memblock_region_memory_end_pfn(reg));
+	}
 }
 #endif
 
@@ -192,6 +213,10 @@ void __init bootmem_init(void)
 
 	early_memtest(min << PAGE_SHIFT, max << PAGE_SHIFT);
 
+	high_memory = __va((max << PAGE_SHIFT) - 1) + 1;
+	max_pfn = max_low_pfn = max;
+
+	arm64_numa_init();
 	/*
 	 * Sparsemem tries to allocate bootmem in memory_present(), so must be
 	 * done after the fixed reservations.
@@ -200,9 +225,6 @@ 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
diff --git a/arch/arm64/mm/numa.c b/arch/arm64/mm/numa.c
new file mode 100644
index 0000000..da1d301
--- /dev/null
+++ b/arch/arm64/mm/numa.c
@@ -0,0 +1,522 @@
+/*
+ * NUMA support, based on the x86 implementation.
+ *
+ * Copyright (C) 2015 Cavium Inc.
+ * Author: Ganapatrao Kulkarni <gkulkarni at 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 <asm/smp_plat.h>
+
+int __initdata numa_off;
+nodemask_t numa_nodes_parsed __initdata;
+static int numa_distance_cnt;
+static u8 *numa_distance;
+
+struct pglist_data *node_data[MAX_NUMNODES] __read_mostly;
+EXPORT_SYMBOL(node_data);
+
+static struct __node_cpu_hwid node_cpu_hwid[NR_CPUS];
+static struct numa_meminfo numa_meminfo;
+
+static __init int numa_setup(char *opt)
+{
+	if (!opt)
+		return -EINVAL;
+	if (!strncmp(opt, "off", 3)) {
+		pr_info("%s\n", "NUMA turned off");
+		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);
+
+void numa_clear_node(int cpu)
+{
+	node_cpu_hwid[cpu].node_id = 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(int cpu)
+{
+	if (IS_ENABLED(CONFIG_ARM64_DT_NUMA))
+		node_cpu_hwid[cpu].node_id  =  dt_get_cpu_node_id(cpu);
+	else
+		node_cpu_hwid[cpu].node_id  =  0;
+
+	/* mapping of MPIDR/hwid, node and logical cpu id */
+	node_cpu_hwid[cpu].cpu_hwid = cpu_logical_map(cpu);
+	cpumask_set_cpu(cpu, node_to_cpumask_map[node_cpu_hwid[cpu].node_id]);
+	set_numa_node(node_cpu_hwid[cpu].node_id);
+	set_numa_mem(local_memory_node(node_cpu_hwid[cpu].node_id));
+}
+
+/**
+ * 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_info("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_info("NUMA: Ignoring memory range 0x%llx - 0x%llx\n",
+			   base, phys_offset);
+		size -= phys_offset - base;
+		base = phys_offset;
+	}
+
+	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;
+
+	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;
+}
+
+/**
+ * numa_reset_distance - Reset NUMA distance table
+ *
+ * The current table is freed.  The next numa_set_distance() call will
+ * create a new one.
+ */
+void __init numa_reset_distance(void)
+{
+	size_t size = numa_distance_cnt * numa_distance_cnt *
+		sizeof(numa_distance[0]);
+
+	/* numa_distance could be 1LU marking allocation failure, test cnt */
+	if (numa_distance_cnt)
+		memblock_free(__pa(numa_distance), size);
+	numa_distance_cnt = 0;
+	numa_distance = NULL;	/* enable table creation */
+}
+
+static int __init numa_alloc_distance(void)
+{
+	nodemask_t nodes_parsed;
+	size_t size;
+	int i, j, cnt = 0;
+	u64 phys;
+
+	/* size the new table and allocate it */
+	nodes_parsed = numa_nodes_parsed;
+	numa_nodemask_from_meminfo(&nodes_parsed, &numa_meminfo);
+
+	for_each_node_mask(i, nodes_parsed)
+		cnt = i;
+	cnt++;
+	size = cnt * cnt * sizeof(numa_distance[0]);
+
+	phys = memblock_find_in_range(0, PFN_PHYS(max_pfn),
+				      size, PAGE_SIZE);
+	if (!phys) {
+		pr_warning("NUMA: Warning: can't allocate distance table!\n");
+		/* don't retry until explicitly reset */
+		numa_distance = (void *)1LU;
+		return -ENOMEM;
+	}
+	memblock_reserve(phys, size);
+
+	numa_distance = __va(phys);
+	numa_distance_cnt = cnt;
+
+	/* fill with the default distances */
+	for (i = 0; i < cnt; i++)
+		for (j = 0; j < cnt; j++)
+			numa_distance[i * cnt + j] = i == j ?
+				LOCAL_DISTANCE : REMOTE_DISTANCE;
+	pr_debug("NUMA: Initialized distance table, cnt=%d\n", cnt);
+
+	return 0;
+}
+
+/**
+ * numa_set_distance - Set NUMA distance from one NUMA to another
+ * @from: the 'from' node to set distance
+ * @to: the 'to'  node to set distance
+ * @distance: NUMA distance
+ *
+ * Set the distance from node @from to @to to @distance.  If distance table
+ * doesn't exist, one which is large enough to accommodate all the currently
+ * known nodes will be created.
+ *
+ * If such table cannot be allocated, a warning is printed and further
+ * calls are ignored until the distance table is reset with
+ * numa_reset_distance().
+ *
+ * If @from or @to is higher than the highest known node or lower than zero
+ * at the time of table creation or @distance doesn't make sense, the call
+ * is ignored.
+ * This is to allow simplification of specific NUMA config implementations.
+ */
+void __init numa_set_distance(int from, int to, int distance)
+{
+	if (!numa_distance && numa_alloc_distance() < 0)
+		return;
+
+	if (from >= numa_distance_cnt || to >= numa_distance_cnt ||
+			from < 0 || to < 0) {
+		pr_warn_once("NUMA: Warning: node ids are out of bound, from=%d to=%d distance=%d\n",
+			    from, to, distance);
+		return;
+	}
+
+	if ((u8)distance != distance ||
+	    (from == to && distance != LOCAL_DISTANCE)) {
+		pr_warn_once("NUMA: Warning: invalid distance parameter, from=%d to=%d distance=%d\n",
+			     from, to, distance);
+		return;
+	}
+
+	numa_distance[from * numa_distance_cnt + to] = distance;
+}
+EXPORT_SYMBOL(numa_set_distance);
+
+int __node_distance(int from, int to)
+{
+	if (from >= numa_distance_cnt || to >= numa_distance_cnt)
+		return from == to ? LOCAL_DISTANCE : REMOTE_DISTANCE;
+	return numa_distance[from * numa_distance_cnt + to];
+}
+EXPORT_SYMBOL(__node_distance);
+
+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(numa_nodes_parsed);
+	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", "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;
+}
+
+/**
+ * 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)
+{
+	int (*init_func)(void) = NULL;
+
+	if (IS_ENABLED(CONFIG_ARM64_DT_NUMA))
+		init_func = arm64_dt_numa_init;
+
+	if (!numa_off && init_func) {
+		if (!numa_init(init_func))
+			return;
+	}
+
+	numa_init(dummy_numa_init);
+}
-- 
2.4.3