arch/x86/kernel/srat_32.c - maze/linux - Git at Google

 /*
  * Some of the code in this file has been gleaned from the 64 bit
  * discontigmem support code base.
  *
  * Copyright (C) 2002, IBM Corp.
  *
  * All rights reserved.
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License as published by
  * the Free Software Foundation; either version 2 of the License, or
  * (at your option) any later version.
  *
  * 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, GOOD TITLE or
  * NON INFRINGEMENT.  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, write to the Free Software
  * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  *
  * Send feedback to Pat Gaughen <gone@us.ibm.com>
  */
 #include <linux/mm.h>
 #include <linux/bootmem.h>
 #include <linux/mmzone.h>
 #include <linux/acpi.h>
 #include <linux/nodemask.h>
 #include <asm/srat.h>
 #include <asm/topology.h>
 #include <asm/smp.h>

 /*
  * proximity macros and definitions
  */
 #define NODE_ARRAY_INDEX(x)	((x) / 8)	/* 8 bits/char */
 #define NODE_ARRAY_OFFSET(x)	((x) % 8)	/* 8 bits/char */
 #define BMAP_SET(bmap, bit)	((bmap)[NODE_ARRAY_INDEX(bit)] |= 1 << NODE_ARRAY_OFFSET(bit))
 #define BMAP_TEST(bmap, bit)	((bmap)[NODE_ARRAY_INDEX(bit)] & (1 << NODE_ARRAY_OFFSET(bit)))
 /* bitmap length; _PXM is at most 255 */
 #define PXM_BITMAP_LEN (MAX_PXM_DOMAINS / 8)
 static u8 pxm_bitmap[PXM_BITMAP_LEN];	/* bitmap of proximity domains */

 #define MAX_CHUNKS_PER_NODE	3
 #define MAXCHUNKS		(MAX_CHUNKS_PER_NODE * MAX_NUMNODES)
 struct node_memory_chunk_s {
 	unsigned long	start_pfn;
 	unsigned long	end_pfn;
 	u8	pxm;		// proximity domain of node
 	u8	nid;		// which cnode contains this chunk?
 	u8	bank;		// which mem bank on this node
 };
 static struct node_memory_chunk_s node_memory_chunk[MAXCHUNKS];

 static int num_memory_chunks;		/* total number of memory chunks */
 static u8 __initdata apicid_to_pxm[MAX_APICID];

 /* Identify CPU proximity domains */
 static void __init parse_cpu_affinity_structure(char *p)
 {
 	struct acpi_srat_cpu_affinity *cpu_affinity =
 				(struct acpi_srat_cpu_affinity *) p;

 	if ((cpu_affinity->flags & ACPI_SRAT_CPU_ENABLED) == 0)
 		return;		/* empty entry */

 	/* mark this node as "seen" in node bitmap */
 	BMAP_SET(pxm_bitmap, cpu_affinity->proximity_domain_lo);

 	apicid_to_pxm[cpu_affinity->apic_id] = cpu_affinity->proximity_domain_lo;

 	printk("CPU 0x%02X in proximity domain 0x%02X\n",
 		cpu_affinity->apic_id, cpu_affinity->proximity_domain_lo);
 }

 /*
  * Identify memory proximity domains and hot-remove capabilities.
  * Fill node memory chunk list structure.
  */
 static void __init parse_memory_affinity_structure (char *sratp)
 {
 	unsigned long long paddr, size;
 	unsigned long start_pfn, end_pfn;
 	u8 pxm;
 	struct node_memory_chunk_s *p, *q, *pend;
 	struct acpi_srat_mem_affinity *memory_affinity =
 			(struct acpi_srat_mem_affinity *) sratp;

 	if ((memory_affinity->flags & ACPI_SRAT_MEM_ENABLED) == 0)
 		return;		/* empty entry */

 	pxm = memory_affinity->proximity_domain & 0xff;

 	/* mark this node as "seen" in node bitmap */
 	BMAP_SET(pxm_bitmap, pxm);

 	/* calculate info for memory chunk structure */
 	paddr = memory_affinity->base_address;
 	size = memory_affinity->length;

 	start_pfn = paddr >> PAGE_SHIFT;
 	end_pfn = (paddr + size) >> PAGE_SHIFT;


 	if (num_memory_chunks >= MAXCHUNKS) {
 		printk("Too many mem chunks in SRAT. Ignoring %lld MBytes at %llx\n",
 			size/(1024*1024), paddr);
 		return;
 	}

 	/* Insertion sort based on base address */
 	pend = &node_memory_chunk[num_memory_chunks];
 	for (p = &node_memory_chunk[0]; p < pend; p++) {
 		if (start_pfn < p->start_pfn)
 			break;
 	}
 	if (p < pend) {
 		for (q = pend; q >= p; q--)
 			*(q + 1) = *q;
 	}
 	p->start_pfn = start_pfn;
 	p->end_pfn = end_pfn;
 	p->pxm = pxm;

 	num_memory_chunks++;

 	printk("Memory range 0x%lX to 0x%lX (type 0x%X) in proximity domain 0x%02X %s\n",
 		start_pfn, end_pfn,
 		memory_affinity->memory_type,
 		pxm,
 		((memory_affinity->flags & ACPI_SRAT_MEM_HOT_PLUGGABLE) ?
 		 "enabled and removable" : "enabled" ) );
 }

 /*
  * The SRAT table always lists ascending addresses, so can always
  * assume that the first "start" address that you see is the real
  * start of the node, and that the current "end" address is after
  * the previous one.
  */
 static __init void node_read_chunk(int nid, struct node_memory_chunk_s *memory_chunk)
 {
 	/*
 	 * Only add present memory as told by the e820.
 	 * There is no guarantee from the SRAT that the memory it
 	 * enumerates is present at boot time because it represents
 	 * *possible* memory hotplug areas the same as normal RAM.
 	 */
 	if (memory_chunk->start_pfn >= max_pfn) {
 		printk (KERN_INFO "Ignoring SRAT pfns: 0x%08lx -> %08lx\n",
 			memory_chunk->start_pfn, memory_chunk->end_pfn);
 		return;
 	}
 	if (memory_chunk->nid != nid)
 		return;

 	if (!node_has_online_mem(nid))
 		node_start_pfn[nid] = memory_chunk->start_pfn;

 	if (node_start_pfn[nid] > memory_chunk->start_pfn)
 		node_start_pfn[nid] = memory_chunk->start_pfn;

 	if (node_end_pfn[nid] < memory_chunk->end_pfn)
 		node_end_pfn[nid] = memory_chunk->end_pfn;
 }

 /* Parse the ACPI Static Resource Affinity Table */
 static int __init acpi20_parse_srat(struct acpi_table_srat *sratp)
 {
 	u8 *start, *end, *p;
 	int i, j, nid;

 	start = (u8 *)(&(sratp->reserved) + 1);	/* skip header */
 	p = start;
 	end = (u8 *)sratp + sratp->header.length;

 	memset(pxm_bitmap, 0, sizeof(pxm_bitmap));	/* init proximity domain bitmap */
 	memset(node_memory_chunk, 0, sizeof(node_memory_chunk));

 	num_memory_chunks = 0;
 	while (p < end) {
 		switch (*p) {
 		case ACPI_SRAT_TYPE_CPU_AFFINITY:
 			parse_cpu_affinity_structure(p);
 			break;
 		case ACPI_SRAT_TYPE_MEMORY_AFFINITY:
 			parse_memory_affinity_structure(p);
 			break;
 		default:
 			printk("ACPI 2.0 SRAT: unknown entry skipped: type=0x%02X, len=%d\n", p[0], p[1]);
 			break;
 		}
 		p += p[1];
 		if (p[1] == 0) {
 			printk("acpi20_parse_srat: Entry length value is zero;"
 				" can't parse any further!\n");
 			break;
 		}
 	}

 	if (num_memory_chunks == 0) {
 		printk("could not finy any ACPI SRAT memory areas.\n");
 		goto out_fail;
 	}

 	/* Calculate total number of nodes in system from PXM bitmap and create
 	 * a set of sequential node IDs starting at zero.  (ACPI doesn't seem
 	 * to specify the range of _PXM values.)
 	 */
 	/*
 	 * MCD - we no longer HAVE to number nodes sequentially.  PXM domain
 	 * numbers could go as high as 256, and MAX_NUMNODES for i386 is typically
 	 * 32, so we will continue numbering them in this manner until MAX_NUMNODES
 	 * approaches MAX_PXM_DOMAINS for i386.
 	 */
 	nodes_clear(node_online_map);
 	for (i = 0; i < MAX_PXM_DOMAINS; i++) {
 		if (BMAP_TEST(pxm_bitmap, i)) {
 			int nid = acpi_map_pxm_to_node(i);
 			node_set_online(nid);
 		}
 	}
 	BUG_ON(num_online_nodes() == 0);

 	/* set cnode id in memory chunk structure */
 	for (i = 0; i < num_memory_chunks; i++)
 		node_memory_chunk[i].nid = pxm_to_node(node_memory_chunk[i].pxm);

 	printk("pxm bitmap: ");
 	for (i = 0; i < sizeof(pxm_bitmap); i++) {
 		printk("%02X ", pxm_bitmap[i]);
 	}
 	printk("\n");
 	printk("Number of logical nodes in system = %d\n", num_online_nodes());
 	printk("Number of memory chunks in system = %d\n", num_memory_chunks);

 	for (i = 0; i < MAX_APICID; i++)
 		apicid_2_node[i] = pxm_to_node(apicid_to_pxm[i]);

 	for (j = 0; j < num_memory_chunks; j++){
 		struct node_memory_chunk_s * chunk = &node_memory_chunk[j];
 		printk("chunk %d nid %d start_pfn %08lx end_pfn %08lx\n",
 		       j, chunk->nid, chunk->start_pfn, chunk->end_pfn);
 		node_read_chunk(chunk->nid, chunk);
 		add_active_range(chunk->nid, chunk->start_pfn, chunk->end_pfn);
 	}

 	for_each_online_node(nid) {
 		unsigned long start = node_start_pfn[nid];
 		unsigned long end = node_end_pfn[nid];

 		memory_present(nid, start, end);
 		node_remap_size[nid] = node_memmap_size_bytes(nid, start, end);
 	}
 	return 1;
 out_fail:
 	return 0;
 }

 struct acpi_static_rsdt {
 	struct acpi_table_rsdt table;
 	u32 padding[7]; /* Allow for 7 more table entries */
 };

 int __init get_memcfg_from_srat(void)
 {
 	struct acpi_table_header *header = NULL;
 	struct acpi_table_rsdp *rsdp = NULL;
 	struct acpi_table_rsdt *rsdt = NULL;
 	acpi_native_uint rsdp_address = 0;
 	struct acpi_static_rsdt saved_rsdt;
 	int tables = 0;
 	int i = 0;

 	rsdp_address = acpi_os_get_root_pointer();
 	if (!rsdp_address) {
 		printk("%s: System description tables not found\n",
 		       __func__);
 		goto out_err;
 	}

 	printk("%s: assigning address to rsdp\n", __func__);
 	rsdp = (struct acpi_table_rsdp *)(u32)rsdp_address;
 	if (!rsdp) {
 		printk("%s: Didn't find ACPI root!\n", __func__);
 		goto out_err;
 	}

 	printk(KERN_INFO "%.8s v%d [%.6s]\n", rsdp->signature, rsdp->revision,
 		rsdp->oem_id);

 	if (strncmp(rsdp->signature, ACPI_SIG_RSDP,strlen(ACPI_SIG_RSDP))) {
 		printk(KERN_WARNING "%s: RSDP table signature incorrect\n", __func__);
 		goto out_err;
 	}

 	rsdt = (struct acpi_table_rsdt *)
 	    early_ioremap(rsdp->rsdt_physical_address, sizeof(struct acpi_table_rsdt));

 	if (!rsdt) {
 		printk(KERN_WARNING
 		       "%s: ACPI: Invalid root system description tables (RSDT)\n",
 		       __func__);
 		goto out_err;
 	}

 	header = &rsdt->header;

 	if (strncmp(header->signature, ACPI_SIG_RSDT, strlen(ACPI_SIG_RSDT))) {
 		printk(KERN_WARNING "ACPI: RSDT signature incorrect\n");
 		goto out_err;
 	}

 	/*
 	 * The number of tables is computed by taking the
 	 * size of all entries (header size minus total
 	 * size of RSDT) divided by the size of each entry
 	 * (4-byte table pointers).
 	 */
 	tables = (header->length - sizeof(struct acpi_table_header)) / 4;

 	if (!tables)
 		goto out_err;

 	memcpy(&saved_rsdt, rsdt, sizeof(saved_rsdt));

 	if (saved_rsdt.table.header.length > sizeof(saved_rsdt)) {
 		printk(KERN_WARNING "ACPI: Too big length in RSDT: %d\n",
 		       saved_rsdt.table.header.length);
 		goto out_err;
 	}

 	printk("Begin SRAT table scan....\n");

 	for (i = 0; i < tables; i++) {
 		/* Map in header, then map in full table length. */
 		header = (struct acpi_table_header *)
 			early_ioremap(saved_rsdt.table.table_offset_entry[i], sizeof(struct acpi_table_header));
 		if (!header)
 			break;
 		header = (struct acpi_table_header *)
 			early_ioremap(saved_rsdt.table.table_offset_entry[i], header->length);
 		if (!header)
 			break;

 		if (strncmp((char *) &header->signature, ACPI_SIG_SRAT, 4))
 			continue;

 		/* we've found the srat table. don't need to look at any more tables */
 		return acpi20_parse_srat((struct acpi_table_srat *)header);
 	}
 out_err:
 	remove_all_active_ranges();
 	printk("failed to get NUMA memory information from SRAT table\n");
 	return 0;
 }
	/*
	* Some of the code in this file has been gleaned from the 64 bit
	* discontigmem support code base.
	*
	* Copyright (C) 2002, IBM Corp.
	*
	* All rights reserved.
	*
	* This program is free software; you can redistribute it and/or modify
	* it under the terms of the GNU General Public License as published by
	* the Free Software Foundation; either version 2 of the License, or
	* (at your option) any later version.
	*
	* 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, GOOD TITLE or
	* NON INFRINGEMENT. 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, write to the Free Software
	* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
	*
	* Send feedback to Pat Gaughen <gone@us.ibm.com>
	*/
	#include <linux/mm.h>
	#include <linux/bootmem.h>
	#include <linux/mmzone.h>
	#include <linux/acpi.h>
	#include <linux/nodemask.h>
	#include <asm/srat.h>
	#include <asm/topology.h>
	#include <asm/smp.h>

	/*
	* proximity macros and definitions
	*/
	#define NODE_ARRAY_INDEX(x) ((x) / 8) /* 8 bits/char */
	#define NODE_ARRAY_OFFSET(x) ((x) % 8) /* 8 bits/char */
	#define BMAP_SET(bmap, bit) ((bmap)[NODE_ARRAY_INDEX(bit)] \|= 1 << NODE_ARRAY_OFFSET(bit))
	#define BMAP_TEST(bmap, bit) ((bmap)[NODE_ARRAY_INDEX(bit)] & (1 << NODE_ARRAY_OFFSET(bit)))
	/* bitmap length; _PXM is at most 255 */
	#define PXM_BITMAP_LEN (MAX_PXM_DOMAINS / 8)
	static u8 pxm_bitmap[PXM_BITMAP_LEN]; /* bitmap of proximity domains */

	#define MAX_CHUNKS_PER_NODE 3
	#define MAXCHUNKS (MAX_CHUNKS_PER_NODE * MAX_NUMNODES)
	struct node_memory_chunk_s {
	unsigned long start_pfn;
	unsigned long end_pfn;
	u8 pxm; // proximity domain of node
	u8 nid; // which cnode contains this chunk?
	u8 bank; // which mem bank on this node
	};
	static struct node_memory_chunk_s node_memory_chunk[MAXCHUNKS];

	static int num_memory_chunks; /* total number of memory chunks */
	static u8 __initdata apicid_to_pxm[MAX_APICID];

	/* Identify CPU proximity domains */
	static void __init parse_cpu_affinity_structure(char *p)
	{
	struct acpi_srat_cpu_affinity *cpu_affinity =
	(struct acpi_srat_cpu_affinity *) p;

	if ((cpu_affinity->flags & ACPI_SRAT_CPU_ENABLED) == 0)
	return; /* empty entry */

	/* mark this node as "seen" in node bitmap */
	BMAP_SET(pxm_bitmap, cpu_affinity->proximity_domain_lo);

	apicid_to_pxm[cpu_affinity->apic_id] = cpu_affinity->proximity_domain_lo;

	printk("CPU 0x%02X in proximity domain 0x%02X\n",
	cpu_affinity->apic_id, cpu_affinity->proximity_domain_lo);
	}

	/*
	* Identify memory proximity domains and hot-remove capabilities.
	* Fill node memory chunk list structure.
	*/
	static void __init parse_memory_affinity_structure (char *sratp)
	{
	unsigned long long paddr, size;
	unsigned long start_pfn, end_pfn;
	u8 pxm;
	struct node_memory_chunk_s p, q, *pend;
	struct acpi_srat_mem_affinity *memory_affinity =
	(struct acpi_srat_mem_affinity *) sratp;

	if ((memory_affinity->flags & ACPI_SRAT_MEM_ENABLED) == 0)
	return; /* empty entry */

	pxm = memory_affinity->proximity_domain & 0xff;

	/* mark this node as "seen" in node bitmap */
	BMAP_SET(pxm_bitmap, pxm);

	/* calculate info for memory chunk structure */
	paddr = memory_affinity->base_address;
	size = memory_affinity->length;

	start_pfn = paddr >> PAGE_SHIFT;
	end_pfn = (paddr + size) >> PAGE_SHIFT;


	if (num_memory_chunks >= MAXCHUNKS) {
	printk("Too many mem chunks in SRAT. Ignoring %lld MBytes at %llx\n",
	size/(1024*1024), paddr);
	return;
	}

	/* Insertion sort based on base address */
	pend = &node_memory_chunk[num_memory_chunks];
	for (p = &node_memory_chunk[0]; p < pend; p++) {
	if (start_pfn < p->start_pfn)
	break;
	}
	if (p < pend) {
	for (q = pend; q >= p; q--)
	(q + 1) = q;
	}
	p->start_pfn = start_pfn;
	p->end_pfn = end_pfn;
	p->pxm = pxm;

	num_memory_chunks++;

	printk("Memory range 0x%lX to 0x%lX (type 0x%X) in proximity domain 0x%02X %s\n",
	start_pfn, end_pfn,
	memory_affinity->memory_type,
	pxm,
	((memory_affinity->flags & ACPI_SRAT_MEM_HOT_PLUGGABLE) ?
	"enabled and removable" : "enabled" ) );
	}

	/*
	* The SRAT table always lists ascending addresses, so can always
	* assume that the first "start" address that you see is the real
	* start of the node, and that the current "end" address is after
	* the previous one.
	*/
	static __init void node_read_chunk(int nid, struct node_memory_chunk_s *memory_chunk)
	{
	/*
	* Only add present memory as told by the e820.
	* There is no guarantee from the SRAT that the memory it
	* enumerates is present at boot time because it represents
	* possible memory hotplug areas the same as normal RAM.
	*/
	if (memory_chunk->start_pfn >= max_pfn) {
	printk (KERN_INFO "Ignoring SRAT pfns: 0x%08lx -> %08lx\n",
	memory_chunk->start_pfn, memory_chunk->end_pfn);
	return;
	}
	if (memory_chunk->nid != nid)
	return;

	if (!node_has_online_mem(nid))
	node_start_pfn[nid] = memory_chunk->start_pfn;

	if (node_start_pfn[nid] > memory_chunk->start_pfn)
	node_start_pfn[nid] = memory_chunk->start_pfn;

	if (node_end_pfn[nid] < memory_chunk->end_pfn)
	node_end_pfn[nid] = memory_chunk->end_pfn;
	}

	/* Parse the ACPI Static Resource Affinity Table */
	static int __init acpi20_parse_srat(struct acpi_table_srat *sratp)
	{
	u8 start, end, *p;
	int i, j, nid;

	start = (u8 )(&(sratp->reserved) + 1); / skip header */
	p = start;
	end = (u8 *)sratp + sratp->header.length;

	memset(pxm_bitmap, 0, sizeof(pxm_bitmap)); /* init proximity domain bitmap */
	memset(node_memory_chunk, 0, sizeof(node_memory_chunk));

	num_memory_chunks = 0;
	while (p < end) {
	switch (*p) {
	case ACPI_SRAT_TYPE_CPU_AFFINITY:
	parse_cpu_affinity_structure(p);
	break;
	case ACPI_SRAT_TYPE_MEMORY_AFFINITY:
	parse_memory_affinity_structure(p);
	break;
	default:
	printk("ACPI 2.0 SRAT: unknown entry skipped: type=0x%02X, len=%d\n", p[0], p[1]);
	break;
	}
	p += p[1];
	if (p[1] == 0) {
	printk("acpi20_parse_srat: Entry length value is zero;"
	" can't parse any further!\n");
	break;
	}
	}

	if (num_memory_chunks == 0) {
	printk("could not finy any ACPI SRAT memory areas.\n");
	goto out_fail;
	}

	/* Calculate total number of nodes in system from PXM bitmap and create
	* a set of sequential node IDs starting at zero. (ACPI doesn't seem
	* to specify the range of _PXM values.)
	*/
	/*
	* MCD - we no longer HAVE to number nodes sequentially. PXM domain
	* numbers could go as high as 256, and MAX_NUMNODES for i386 is typically
	* 32, so we will continue numbering them in this manner until MAX_NUMNODES
	* approaches MAX_PXM_DOMAINS for i386.
	*/
	nodes_clear(node_online_map);
	for (i = 0; i < MAX_PXM_DOMAINS; i++) {
	if (BMAP_TEST(pxm_bitmap, i)) {
	int nid = acpi_map_pxm_to_node(i);
	node_set_online(nid);
	}
	}
	BUG_ON(num_online_nodes() == 0);

	/* set cnode id in memory chunk structure */
	for (i = 0; i < num_memory_chunks; i++)
	node_memory_chunk[i].nid = pxm_to_node(node_memory_chunk[i].pxm);

	printk("pxm bitmap: ");
	for (i = 0; i < sizeof(pxm_bitmap); i++) {
	printk("%02X ", pxm_bitmap[i]);
	}
	printk("\n");
	printk("Number of logical nodes in system = %d\n", num_online_nodes());
	printk("Number of memory chunks in system = %d\n", num_memory_chunks);

	for (i = 0; i < MAX_APICID; i++)
	apicid_2_node[i] = pxm_to_node(apicid_to_pxm[i]);

	for (j = 0; j < num_memory_chunks; j++){
	struct node_memory_chunk_s * chunk = &node_memory_chunk[j];
	printk("chunk %d nid %d start_pfn %08lx end_pfn %08lx\n",
	j, chunk->nid, chunk->start_pfn, chunk->end_pfn);
	node_read_chunk(chunk->nid, chunk);
	add_active_range(chunk->nid, chunk->start_pfn, chunk->end_pfn);
	}

	for_each_online_node(nid) {
	unsigned long start = node_start_pfn[nid];
	unsigned long end = node_end_pfn[nid];

	memory_present(nid, start, end);
	node_remap_size[nid] = node_memmap_size_bytes(nid, start, end);
	}
	return 1;
	out_fail:
	return 0;
	}

	struct acpi_static_rsdt {
	struct acpi_table_rsdt table;
	u32 padding[7]; /* Allow for 7 more table entries */
	};

	int __init get_memcfg_from_srat(void)
	{
	struct acpi_table_header *header = NULL;
	struct acpi_table_rsdp *rsdp = NULL;
	struct acpi_table_rsdt *rsdt = NULL;
	acpi_native_uint rsdp_address = 0;
	struct acpi_static_rsdt saved_rsdt;
	int tables = 0;
	int i = 0;

	rsdp_address = acpi_os_get_root_pointer();
	if (!rsdp_address) {
	printk("%s: System description tables not found\n",
	__func__);
	goto out_err;
	}

	printk("%s: assigning address to rsdp\n", __func__);
	rsdp = (struct acpi_table_rsdp *)(u32)rsdp_address;
	if (!rsdp) {
	printk("%s: Didn't find ACPI root!\n", __func__);
	goto out_err;
	}

	printk(KERN_INFO "%.8s v%d [%.6s]\n", rsdp->signature, rsdp->revision,
	rsdp->oem_id);

	if (strncmp(rsdp->signature, ACPI_SIG_RSDP,strlen(ACPI_SIG_RSDP))) {
	printk(KERN_WARNING "%s: RSDP table signature incorrect\n", __func__);
	goto out_err;
	}

	rsdt = (struct acpi_table_rsdt *)
	early_ioremap(rsdp->rsdt_physical_address, sizeof(struct acpi_table_rsdt));

	if (!rsdt) {
	printk(KERN_WARNING
	"%s: ACPI: Invalid root system description tables (RSDT)\n",
	__func__);
	goto out_err;
	}

	header = &rsdt->header;

	if (strncmp(header->signature, ACPI_SIG_RSDT, strlen(ACPI_SIG_RSDT))) {
	printk(KERN_WARNING "ACPI: RSDT signature incorrect\n");
	goto out_err;
	}

	/*
	* The number of tables is computed by taking the
	* size of all entries (header size minus total
	* size of RSDT) divided by the size of each entry
	* (4-byte table pointers).
	*/
	tables = (header->length - sizeof(struct acpi_table_header)) / 4;

	if (!tables)
	goto out_err;

	memcpy(&saved_rsdt, rsdt, sizeof(saved_rsdt));

	if (saved_rsdt.table.header.length > sizeof(saved_rsdt)) {
	printk(KERN_WARNING "ACPI: Too big length in RSDT: %d\n",
	saved_rsdt.table.header.length);
	goto out_err;
	}

	printk("Begin SRAT table scan....\n");

	for (i = 0; i < tables; i++) {
	/* Map in header, then map in full table length. */
	header = (struct acpi_table_header *)
	early_ioremap(saved_rsdt.table.table_offset_entry[i], sizeof(struct acpi_table_header));
	if (!header)
	break;
	header = (struct acpi_table_header *)
	early_ioremap(saved_rsdt.table.table_offset_entry[i], header->length);
	if (!header)
	break;

	if (strncmp((char *) &header->signature, ACPI_SIG_SRAT, 4))
	continue;

	/* we've found the srat table. don't need to look at any more tables */
	return acpi20_parse_srat((struct acpi_table_srat *)header);
	}
	out_err:
	remove_all_active_ranges();
	printk("failed to get NUMA memory information from SRAT table\n");
	return 0;
	}