arch/arm64/mm/numa.c - kernel/msm-4.9 - Gitiles

 /*
  * NUMA support, based on the x86 implementation.
  *
  * Copyright (C) 2015 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/>.
  */

 #define pr_fmt(fmt) "NUMA: " fmt

 #include <linux/acpi.h>
 #include <linux/bootmem.h>
 #include <linux/memblock.h>
 #include <linux/module.h>
 #include <linux/of.h>

 #include <asm/acpi.h>
 #include <asm/sections.h>

 struct pglist_data *node_data[MAX_NUMNODES] __read_mostly;
 EXPORT_SYMBOL(node_data);
 nodemask_t numa_nodes_parsed __initdata;
 static int cpu_to_node_map[NR_CPUS] = { [0 ... NR_CPUS-1] = NUMA_NO_NODE };

 static int numa_distance_cnt;
 static u8 *numa_distance;
 static bool numa_off;

 static __init int numa_parse_early_param(char *opt)
 {
 	if (!opt)
 		return -EINVAL;
 	if (!strncmp(opt, "off", 3))
 		numa_off = true;

 	return 0;
 }
 early_param("numa", numa_parse_early_param);

 cpumask_var_t node_to_cpumask_map[MAX_NUMNODES];
 EXPORT_SYMBOL(node_to_cpumask_map);

 #ifdef CONFIG_DEBUG_PER_CPU_MAPS

 /*
  * Returns a pointer to the bitmask of CPUs on Node 'node'.
  */
 const struct cpumask *cpumask_of_node(int node)
 {

 	if (node == NUMA_NO_NODE)
 		return cpu_all_mask;

 	if (WARN_ON(node < 0 || node >= nr_node_ids))
 		return cpu_none_mask;

 	if (WARN_ON(node_to_cpumask_map[node] == NULL))
 		return cpu_online_mask;

 	return node_to_cpumask_map[node];
 }
 EXPORT_SYMBOL(cpumask_of_node);

 #endif

 static void map_cpu_to_node(unsigned int cpu, int nid)
 {
 	set_cpu_numa_node(cpu, nid);
 	if (nid >= 0)
 		cpumask_set_cpu(cpu, node_to_cpumask_map[nid]);
 }

 void numa_clear_node(unsigned int cpu)
 {
 	int nid = cpu_to_node(cpu);

 	if (nid >= 0)
 		cpumask_clear_cpu(cpu, node_to_cpumask_map[nid]);
 	set_cpu_numa_node(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.)
  */
 static void __init setup_node_to_cpumask_map(void)
 {
 	int node;

 	/* setup nr_node_ids if not done yet */
 	if (nr_node_ids == MAX_NUMNODES)
 		setup_nr_node_ids();

 	/* allocate and clear the mapping */
 	for (node = 0; node < nr_node_ids; node++) {
 		alloc_bootmem_cpumask_var(&node_to_cpumask_map[node]);
 		cpumask_clear(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(unsigned int cpu)
 {
 	map_cpu_to_node(cpu, cpu_to_node_map[cpu]);
 }

 void __init early_map_cpu_to_node(unsigned int cpu, int nid)
 {
 	/* fallback to node 0 */
 	if (nid < 0 || nid >= MAX_NUMNODES || numa_off)
 		nid = 0;

 	cpu_to_node_map[cpu] = nid;

 	/*
 	 * We should set the numa node of cpu0 as soon as possible, because it
 	 * has already been set up online before. cpu_to_node(0) will soon be
 	 * called.
 	 */
 	if (!cpu)
 		set_cpu_numa_node(cpu, nid);
 }

 #ifdef CONFIG_HAVE_SETUP_PER_CPU_AREA
 unsigned long __per_cpu_offset[NR_CPUS] __read_mostly;
 EXPORT_SYMBOL(__per_cpu_offset);

 static int __init early_cpu_to_node(int cpu)
 {
 	return cpu_to_node_map[cpu];
 }

 static int __init pcpu_cpu_distance(unsigned int from, unsigned int to)
 {
 	return node_distance(early_cpu_to_node(from), early_cpu_to_node(to));
 }

 static void * __init pcpu_fc_alloc(unsigned int cpu, size_t size,
 				       size_t align)
 {
 	int nid = early_cpu_to_node(cpu);

 	return  memblock_virt_alloc_try_nid(size, align,
 			__pa(MAX_DMA_ADDRESS), MEMBLOCK_ALLOC_ACCESSIBLE, nid);
 }

 static void __init pcpu_fc_free(void *ptr, size_t size)
 {
 	memblock_free_early(__pa(ptr), size);
 }

 void __init setup_per_cpu_areas(void)
 {
 	unsigned long delta;
 	unsigned int cpu;
 	int rc;

 	/*
 	 * Always reserve area for module percpu variables.  That's
 	 * what the legacy allocator did.
 	 */
 	rc = pcpu_embed_first_chunk(PERCPU_MODULE_RESERVE,
 				    PERCPU_DYNAMIC_RESERVE, PAGE_SIZE,
 				    pcpu_cpu_distance,
 				    pcpu_fc_alloc, pcpu_fc_free);
 	if (rc < 0)
 		panic("Failed to initialize percpu areas.");

 	delta = (unsigned long)pcpu_base_addr - (unsigned long)__per_cpu_start;
 	for_each_possible_cpu(cpu)
 		__per_cpu_offset[cpu] = delta + pcpu_unit_offsets[cpu];
 }
 #endif

 /**
  * numa_add_memblk - Set node id to memblk
  * @nid: NUMA node ID of the new memblk
  * @start: Start address of the new memblk
  * @end:  End address of the new memblk
  *
  * RETURNS:
  * 0 on success, -errno on failure.
  */
 int __init numa_add_memblk(int nid, u64 start, u64 end)
 {
 	int ret;

 	ret = memblock_set_node(start, (end - start), &memblock.memory, nid);
 	if (ret < 0) {
 		pr_err("memblock [0x%llx - 0x%llx] failed to add on node %d\n",
 			start, (end - 1), nid);
 		return ret;
 	}

 	node_set(nid, numa_nodes_parsed);
 	pr_info("Adding memblock [0x%llx - 0x%llx] on node %d\n",
 			start, (end - 1), nid);
 	return ret;
 }

 /**
  * Initialize NODE_DATA for a node on the local memory
  */
 static void __init setup_node_data(int nid, u64 start_pfn, u64 end_pfn)
 {
 	const size_t nd_size = roundup(sizeof(pg_data_t), SMP_CACHE_BYTES);
 	u64 nd_pa;
 	void *nd;
 	int tnid;

 	if (start_pfn < end_pfn)
 		pr_info("Initmem setup node %d [mem %#010Lx-%#010Lx]\n", nid,
 			start_pfn << PAGE_SHIFT, (end_pfn << PAGE_SHIFT) - 1);
 	else
 		pr_info("Initmem setup node %d [<memory-less node>]\n", nid);

 	nd_pa = memblock_alloc_try_nid(nd_size, SMP_CACHE_BYTES, nid);
 	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_pfn;
 	NODE_DATA(nid)->node_spanned_pages = end_pfn - start_pfn;
 }

 /**
  * numa_free_distance
  *
  * The current table is freed.
  */
 void __init numa_free_distance(void)
 {
 	size_t size;

 	if (!numa_distance)
 		return;

 	size = numa_distance_cnt * numa_distance_cnt *
 		sizeof(numa_distance[0]);

 	memblock_free(__pa(numa_distance), size);
 	numa_distance_cnt = 0;
 	numa_distance = NULL;
 }

 /**
  *
  * Create a new NUMA distance table.
  *
  */
 static int __init numa_alloc_distance(void)
 {
 	size_t size;
 	u64 phys;
 	int i, j;

 	size = nr_node_ids * nr_node_ids * sizeof(numa_distance[0]);
 	phys = memblock_find_in_range(0, PFN_PHYS(max_pfn),
 				      size, PAGE_SIZE);
 	if (WARN_ON(!phys))
 		return -ENOMEM;

 	memblock_reserve(phys, size);

 	numa_distance = __va(phys);
 	numa_distance_cnt = nr_node_ids;

 	/* fill with the default distances */
 	for (i = 0; i < numa_distance_cnt; i++)
 		for (j = 0; j < numa_distance_cnt; j++)
 			numa_distance[i * numa_distance_cnt + j] = i == j ?
 				LOCAL_DISTANCE : REMOTE_DISTANCE;

 	pr_debug("Initialized distance table, cnt=%d\n", numa_distance_cnt);

 	return 0;
 }

 /**
  * numa_set_distance - Set inter node NUMA distance from node to node.
  * @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, a warning is printed.
  *
  * If @from or @to is higher than the highest known node or lower than zero
  * or @distance doesn't make sense, the call is ignored.
  *
  */
 void __init numa_set_distance(int from, int to, int distance)
 {
 	if (!numa_distance) {
 		pr_warn_once("Warning: distance table not allocated yet\n");
 		return;
 	}

 	if (from >= numa_distance_cnt || to >= numa_distance_cnt ||
 			from < 0 || to < 0) {
 		pr_warn_once("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("Warning: invalid distance parameter, from=%d to=%d distance=%d\n",
 			     from, to, distance);
 		return;
 	}

 	numa_distance[from * numa_distance_cnt + to] = distance;
 }

 /**
  * Return NUMA distance @from to @to
  */
 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_nodes(void)
 {
 	int nid;
 	struct memblock_region *mblk;

 	/* Check that valid nid is set to memblks */
 	for_each_memblock(memory, mblk)
 		if (mblk->nid == NUMA_NO_NODE || mblk->nid >= MAX_NUMNODES) {
 			pr_warn("Warning: invalid memblk node %d [mem %#010Lx-%#010Lx]\n",
 				mblk->nid, mblk->base,
 				mblk->base + mblk->size - 1);
 			return -EINVAL;
 		}

 	/* Finally register nodes. */
 	for_each_node_mask(nid, numa_nodes_parsed) {
 		unsigned long start_pfn, end_pfn;

 		get_pfn_range_for_nid(nid, &start_pfn, &end_pfn);
 		setup_node_data(nid, start_pfn, end_pfn);
 		node_set_online(nid);
 	}

 	/* Setup online nodes to actual nodes*/
 	node_possible_map = numa_nodes_parsed;

 	return 0;
 }

 static int __init numa_init(int (*init_func)(void))
 {
 	int ret;

 	nodes_clear(numa_nodes_parsed);
 	nodes_clear(node_possible_map);
 	nodes_clear(node_online_map);
 	numa_free_distance();

 	ret = numa_alloc_distance();
 	if (ret < 0)
 		return ret;

 	ret = init_func();
 	if (ret < 0)
 		return ret;

 	if (nodes_empty(numa_nodes_parsed)) {
 		pr_info("No NUMA configuration found\n");
 		return -EINVAL;
 	}

 	ret = numa_register_nodes();
 	if (ret < 0)
 		return ret;

 	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 (node 0) and add memory blocks that cover all
  * allowed memory. It is unlikely that this function fails.
  */
 static int __init dummy_numa_init(void)
 {
 	int ret;
 	struct memblock_region *mblk;

 	if (numa_off)
 		pr_info("NUMA disabled\n"); /* Forced off on command line. */
 	pr_info("Faking a node at [mem %#018Lx-%#018Lx]\n",
 		memblock_start_of_DRAM(), memblock_end_of_DRAM() - 1);

 	for_each_memblock(memory, mblk) {
 		ret = numa_add_memblk(0, mblk->base, mblk->base + mblk->size);
 		if (!ret)
 			continue;

 		pr_err("NUMA init failed\n");
 		return ret;
 	}

 	numa_off = true;
 	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.
  */
 void __init arm64_numa_init(void)
 {
 	if (!numa_off) {
 		if (!acpi_disabled && !numa_init(arm64_acpi_numa_init))
 			return;
 		if (acpi_disabled && !numa_init(of_numa_init))
 			return;
 	}

 	numa_init(dummy_numa_init);
 }
	/*
	* NUMA support, based on the x86 implementation.
	*
	* Copyright (C) 2015 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/>.
	*/

	#define pr_fmt(fmt) "NUMA: " fmt

	#include <linux/acpi.h>
	#include <linux/bootmem.h>
	#include <linux/memblock.h>
	#include <linux/module.h>
	#include <linux/of.h>

	#include <asm/acpi.h>
	#include <asm/sections.h>

	struct pglist_data *node_data[MAX_NUMNODES] __read_mostly;
	EXPORT_SYMBOL(node_data);
	nodemask_t numa_nodes_parsed __initdata;
	static int cpu_to_node_map[NR_CPUS] = { [0 ... NR_CPUS-1] = NUMA_NO_NODE };

	static int numa_distance_cnt;
	static u8 *numa_distance;
	static bool numa_off;

	static __init int numa_parse_early_param(char *opt)
	{
	if (!opt)
	return -EINVAL;
	if (!strncmp(opt, "off", 3))
	numa_off = true;

	return 0;
	}
	early_param("numa", numa_parse_early_param);

	cpumask_var_t node_to_cpumask_map[MAX_NUMNODES];
	EXPORT_SYMBOL(node_to_cpumask_map);

	#ifdef CONFIG_DEBUG_PER_CPU_MAPS

	/*
	* Returns a pointer to the bitmask of CPUs on Node 'node'.
	*/
	const struct cpumask *cpumask_of_node(int node)
	{

	if (node == NUMA_NO_NODE)
	return cpu_all_mask;

	if (WARN_ON(node < 0 \|\| node >= nr_node_ids))
	return cpu_none_mask;

	if (WARN_ON(node_to_cpumask_map[node] == NULL))
	return cpu_online_mask;

	return node_to_cpumask_map[node];
	}
	EXPORT_SYMBOL(cpumask_of_node);

	#endif

	static void map_cpu_to_node(unsigned int cpu, int nid)
	{
	set_cpu_numa_node(cpu, nid);
	if (nid >= 0)
	cpumask_set_cpu(cpu, node_to_cpumask_map[nid]);
	}

	void numa_clear_node(unsigned int cpu)
	{
	int nid = cpu_to_node(cpu);

	if (nid >= 0)
	cpumask_clear_cpu(cpu, node_to_cpumask_map[nid]);
	set_cpu_numa_node(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.)
	*/
	static void __init setup_node_to_cpumask_map(void)
	{
	int node;

	/* setup nr_node_ids if not done yet */
	if (nr_node_ids == MAX_NUMNODES)
	setup_nr_node_ids();

	/* allocate and clear the mapping */
	for (node = 0; node < nr_node_ids; node++) {
	alloc_bootmem_cpumask_var(&node_to_cpumask_map[node]);
	cpumask_clear(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(unsigned int cpu)
	{
	map_cpu_to_node(cpu, cpu_to_node_map[cpu]);
	}

	void __init early_map_cpu_to_node(unsigned int cpu, int nid)
	{
	/* fallback to node 0 */
	if (nid < 0 \|\| nid >= MAX_NUMNODES \|\| numa_off)
	nid = 0;

	cpu_to_node_map[cpu] = nid;

	/*
	* We should set the numa node of cpu0 as soon as possible, because it
	* has already been set up online before. cpu_to_node(0) will soon be
	* called.
	*/
	if (!cpu)
	set_cpu_numa_node(cpu, nid);
	}

	#ifdef CONFIG_HAVE_SETUP_PER_CPU_AREA
	unsigned long __per_cpu_offset[NR_CPUS] __read_mostly;
	EXPORT_SYMBOL(__per_cpu_offset);

	static int __init early_cpu_to_node(int cpu)
	{
	return cpu_to_node_map[cpu];
	}

	static int __init pcpu_cpu_distance(unsigned int from, unsigned int to)
	{
	return node_distance(early_cpu_to_node(from), early_cpu_to_node(to));
	}

	static void * __init pcpu_fc_alloc(unsigned int cpu, size_t size,
	size_t align)
	{
	int nid = early_cpu_to_node(cpu);

	return memblock_virt_alloc_try_nid(size, align,
	__pa(MAX_DMA_ADDRESS), MEMBLOCK_ALLOC_ACCESSIBLE, nid);
	}

	static void __init pcpu_fc_free(void *ptr, size_t size)
	{
	memblock_free_early(__pa(ptr), size);
	}

	void __init setup_per_cpu_areas(void)
	{
	unsigned long delta;
	unsigned int cpu;
	int rc;

	/*
	* Always reserve area for module percpu variables. That's
	* what the legacy allocator did.
	*/
	rc = pcpu_embed_first_chunk(PERCPU_MODULE_RESERVE,
	PERCPU_DYNAMIC_RESERVE, PAGE_SIZE,
	pcpu_cpu_distance,
	pcpu_fc_alloc, pcpu_fc_free);
	if (rc < 0)
	panic("Failed to initialize percpu areas.");

	delta = (unsigned long)pcpu_base_addr - (unsigned long)__per_cpu_start;
	for_each_possible_cpu(cpu)
	__per_cpu_offset[cpu] = delta + pcpu_unit_offsets[cpu];
	}
	#endif

	/**
	* numa_add_memblk - Set node id to memblk
	* @nid: NUMA node ID of the new memblk
	* @start: Start address of the new memblk
	* @end: End address of the new memblk
	*
	* RETURNS:
	* 0 on success, -errno on failure.
	*/
	int __init numa_add_memblk(int nid, u64 start, u64 end)
	{
	int ret;

	ret = memblock_set_node(start, (end - start), &memblock.memory, nid);
	if (ret < 0) {
	pr_err("memblock [0x%llx - 0x%llx] failed to add on node %d\n",
	start, (end - 1), nid);
	return ret;
	}

	node_set(nid, numa_nodes_parsed);
	pr_info("Adding memblock [0x%llx - 0x%llx] on node %d\n",
	start, (end - 1), nid);
	return ret;
	}

	/**
	* Initialize NODE_DATA for a node on the local memory
	*/
	static void __init setup_node_data(int nid, u64 start_pfn, u64 end_pfn)
	{
	const size_t nd_size = roundup(sizeof(pg_data_t), SMP_CACHE_BYTES);
	u64 nd_pa;
	void *nd;
	int tnid;

	if (start_pfn < end_pfn)
	pr_info("Initmem setup node %d [mem %#010Lx-%#010Lx]\n", nid,
	start_pfn << PAGE_SHIFT, (end_pfn << PAGE_SHIFT) - 1);
	else
	pr_info("Initmem setup node %d [<memory-less node>]\n", nid);

	nd_pa = memblock_alloc_try_nid(nd_size, SMP_CACHE_BYTES, nid);
	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_pfn;
	NODE_DATA(nid)->node_spanned_pages = end_pfn - start_pfn;
	}

	/**
	* numa_free_distance
	*
	* The current table is freed.
	*/
	void __init numa_free_distance(void)
	{
	size_t size;

	if (!numa_distance)
	return;

	size = numa_distance_cnt * numa_distance_cnt *
	sizeof(numa_distance[0]);

	memblock_free(__pa(numa_distance), size);
	numa_distance_cnt = 0;
	numa_distance = NULL;
	}

	/**
	*
	* Create a new NUMA distance table.
	*
	*/
	static int __init numa_alloc_distance(void)
	{
	size_t size;
	u64 phys;
	int i, j;

	size = nr_node_ids * nr_node_ids * sizeof(numa_distance[0]);
	phys = memblock_find_in_range(0, PFN_PHYS(max_pfn),
	size, PAGE_SIZE);
	if (WARN_ON(!phys))
	return -ENOMEM;

	memblock_reserve(phys, size);

	numa_distance = __va(phys);
	numa_distance_cnt = nr_node_ids;

	/* fill with the default distances */
	for (i = 0; i < numa_distance_cnt; i++)
	for (j = 0; j < numa_distance_cnt; j++)
	numa_distance[i * numa_distance_cnt + j] = i == j ?
	LOCAL_DISTANCE : REMOTE_DISTANCE;

	pr_debug("Initialized distance table, cnt=%d\n", numa_distance_cnt);

	return 0;
	}

	/**
	* numa_set_distance - Set inter node NUMA distance from node to node.
	* @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, a warning is printed.
	*
	* If @from or @to is higher than the highest known node or lower than zero
	* or @distance doesn't make sense, the call is ignored.
	*
	*/
	void __init numa_set_distance(int from, int to, int distance)
	{
	if (!numa_distance) {
	pr_warn_once("Warning: distance table not allocated yet\n");
	return;
	}

	if (from >= numa_distance_cnt \|\| to >= numa_distance_cnt \|\|
	from < 0 \|\| to < 0) {
	pr_warn_once("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("Warning: invalid distance parameter, from=%d to=%d distance=%d\n",
	from, to, distance);
	return;
	}

	numa_distance[from * numa_distance_cnt + to] = distance;
	}

	/**
	* Return NUMA distance @from to @to
	*/
	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_nodes(void)
	{
	int nid;
	struct memblock_region *mblk;

	/* Check that valid nid is set to memblks */
	for_each_memblock(memory, mblk)
	if (mblk->nid == NUMA_NO_NODE \|\| mblk->nid >= MAX_NUMNODES) {
	pr_warn("Warning: invalid memblk node %d [mem %#010Lx-%#010Lx]\n",
	mblk->nid, mblk->base,
	mblk->base + mblk->size - 1);
	return -EINVAL;
	}

	/* Finally register nodes. */
	for_each_node_mask(nid, numa_nodes_parsed) {
	unsigned long start_pfn, end_pfn;

	get_pfn_range_for_nid(nid, &start_pfn, &end_pfn);
	setup_node_data(nid, start_pfn, end_pfn);
	node_set_online(nid);
	}

	/* Setup online nodes to actual nodes*/
	node_possible_map = numa_nodes_parsed;

	return 0;
	}

	static int __init numa_init(int (*init_func)(void))
	{
	int ret;

	nodes_clear(numa_nodes_parsed);
	nodes_clear(node_possible_map);
	nodes_clear(node_online_map);
	numa_free_distance();

	ret = numa_alloc_distance();
	if (ret < 0)
	return ret;

	ret = init_func();
	if (ret < 0)
	return ret;

	if (nodes_empty(numa_nodes_parsed)) {
	pr_info("No NUMA configuration found\n");
	return -EINVAL;
	}

	ret = numa_register_nodes();
	if (ret < 0)
	return ret;

	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 (node 0) and add memory blocks that cover all
	* allowed memory. It is unlikely that this function fails.
	*/
	static int __init dummy_numa_init(void)
	{
	int ret;
	struct memblock_region *mblk;

	if (numa_off)
	pr_info("NUMA disabled\n"); /* Forced off on command line. */
	pr_info("Faking a node at [mem %#018Lx-%#018Lx]\n",
	memblock_start_of_DRAM(), memblock_end_of_DRAM() - 1);

	for_each_memblock(memory, mblk) {
	ret = numa_add_memblk(0, mblk->base, mblk->base + mblk->size);
	if (!ret)
	continue;

	pr_err("NUMA init failed\n");
	return ret;
	}

	numa_off = true;
	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.
	*/
	void __init arm64_numa_init(void)
	{
	if (!numa_off) {
	if (!acpi_disabled && !numa_init(arm64_acpi_numa_init))
	return;
	if (acpi_disabled && !numa_init(of_numa_init))
	return;
	}

	numa_init(dummy_numa_init);
	}