arch/arm/mm/init.c - linux - Git at Google

 /*
  *  linux/arch/arm/mm/init.c
  *
  *  Copyright (C) 1995-2005 Russell King
  *
  * 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.
  */
 #include <linux/config.h>
 #include <linux/kernel.h>
 #include <linux/errno.h>
 #include <linux/ptrace.h>
 #include <linux/swap.h>
 #include <linux/init.h>
 #include <linux/bootmem.h>
 #include <linux/mman.h>
 #include <linux/nodemask.h>
 #include <linux/initrd.h>

 #include <asm/mach-types.h>
 #include <asm/setup.h>
 #include <asm/tlb.h>

 #include <asm/mach/arch.h>
 #include <asm/mach/map.h>

 #define TABLE_SIZE	(2 * PTRS_PER_PTE * sizeof(pte_t))

 DEFINE_PER_CPU(struct mmu_gather, mmu_gathers);

 extern pgd_t swapper_pg_dir[PTRS_PER_PGD];
 extern void _stext, _text, _etext, __data_start, _end, __init_begin, __init_end;
 extern unsigned long phys_initrd_start;
 extern unsigned long phys_initrd_size;

 /*
  * The sole use of this is to pass memory configuration
  * data from paging_init to mem_init.
  */
 static struct meminfo meminfo __initdata = { 0, };

 /*
  * empty_zero_page is a special page that is used for
  * zero-initialized data and COW.
  */
 struct page *empty_zero_page;

 void show_mem(void)
 {
 	int free = 0, total = 0, reserved = 0;
 	int shared = 0, cached = 0, slab = 0, node;

 	printk("Mem-info:\n");
 	show_free_areas();
 	printk("Free swap:       %6ldkB\n", nr_swap_pages<<(PAGE_SHIFT-10));

 	for_each_online_node(node) {
 		struct page *page, *end;

 		page = NODE_MEM_MAP(node);
 		end  = page + NODE_DATA(node)->node_spanned_pages;

 		do {
 			total++;
 			if (PageReserved(page))
 				reserved++;
 			else if (PageSwapCache(page))
 				cached++;
 			else if (PageSlab(page))
 				slab++;
 			else if (!page_count(page))
 				free++;
 			else
 				shared += page_count(page) - 1;
 			page++;
 		} while (page < end);
 	}

 	printk("%d pages of RAM\n", total);
 	printk("%d free pages\n", free);
 	printk("%d reserved pages\n", reserved);
 	printk("%d slab pages\n", slab);
 	printk("%d pages shared\n", shared);
 	printk("%d pages swap cached\n", cached);
 }

 static inline pmd_t *pmd_off(pgd_t *pgd, unsigned long virt)
 {
 	return pmd_offset(pgd, virt);
 }

 static inline pmd_t *pmd_off_k(unsigned long virt)
 {
 	return pmd_off(pgd_offset_k(virt), virt);
 }

 #define for_each_nodebank(iter,mi,no)			\
 	for (iter = 0; iter < mi->nr_banks; iter++)	\
 		if (mi->bank[iter].node == no)

 /*
  * FIXME: We really want to avoid allocating the bootmap bitmap
  * over the top of the initrd.  Hopefully, this is located towards
  * the start of a bank, so if we allocate the bootmap bitmap at
  * the end, we won't clash.
  */
 static unsigned int __init
 find_bootmap_pfn(int node, struct meminfo *mi, unsigned int bootmap_pages)
 {
 	unsigned int start_pfn, bank, bootmap_pfn;

 	start_pfn   = PAGE_ALIGN(__pa(&_end)) >> PAGE_SHIFT;
 	bootmap_pfn = 0;

 	for_each_nodebank(bank, mi, node) {
 		unsigned int start, end;

 		start = mi->bank[bank].start >> PAGE_SHIFT;
 		end   = (mi->bank[bank].size +
 			 mi->bank[bank].start) >> PAGE_SHIFT;

 		if (end < start_pfn)
 			continue;

 		if (start < start_pfn)
 			start = start_pfn;

 		if (end <= start)
 			continue;

 		if (end - start >= bootmap_pages) {
 			bootmap_pfn = start;
 			break;
 		}
 	}

 	if (bootmap_pfn == 0)
 		BUG();

 	return bootmap_pfn;
 }

 static int __init check_initrd(struct meminfo *mi)
 {
 	int initrd_node = -2;
 #ifdef CONFIG_BLK_DEV_INITRD
 	unsigned long end = phys_initrd_start + phys_initrd_size;

 	/*
 	 * Make sure that the initrd is within a valid area of
 	 * memory.
 	 */
 	if (phys_initrd_size) {
 		unsigned int i;

 		initrd_node = -1;

 		for (i = 0; i < mi->nr_banks; i++) {
 			unsigned long bank_end;

 			bank_end = mi->bank[i].start + mi->bank[i].size;

 			if (mi->bank[i].start <= phys_initrd_start &&
 			    end <= bank_end)
 				initrd_node = mi->bank[i].node;
 		}
 	}

 	if (initrd_node == -1) {
 		printk(KERN_ERR "initrd (0x%08lx - 0x%08lx) extends beyond "
 		       "physical memory - disabling initrd\n",
 		       phys_initrd_start, end);
 		phys_initrd_start = phys_initrd_size = 0;
 	}
 #endif

 	return initrd_node;
 }

 /*
  * Reserve the various regions of node 0
  */
 static __init void reserve_node_zero(pg_data_t *pgdat)
 {
 	unsigned long res_size = 0;

 	/*
 	 * Register the kernel text and data with bootmem.
 	 * Note that this can only be in node 0.
 	 */
 #ifdef CONFIG_XIP_KERNEL
 	reserve_bootmem_node(pgdat, __pa(&__data_start), &_end - &__data_start);
 #else
 	reserve_bootmem_node(pgdat, __pa(&_stext), &_end - &_stext);
 #endif

 	/*
 	 * Reserve the page tables.  These are already in use,
 	 * and can only be in node 0.
 	 */
 	reserve_bootmem_node(pgdat, __pa(swapper_pg_dir),
 			     PTRS_PER_PGD * sizeof(pgd_t));

 	/*
 	 * Hmm... This should go elsewhere, but we really really need to
 	 * stop things allocating the low memory; ideally we need a better
 	 * implementation of GFP_DMA which does not assume that DMA-able
 	 * memory starts at zero.
 	 */
 	if (machine_is_integrator() || machine_is_cintegrator())
 		res_size = __pa(swapper_pg_dir) - PHYS_OFFSET;

 	/*
 	 * These should likewise go elsewhere.  They pre-reserve the
 	 * screen memory region at the start of main system memory.
 	 */
 	if (machine_is_edb7211())
 		res_size = 0x00020000;
 	if (machine_is_p720t())
 		res_size = 0x00014000;

 #ifdef CONFIG_SA1111
 	/*
 	 * Because of the SA1111 DMA bug, we want to preserve our
 	 * precious DMA-able memory...
 	 */
 	res_size = __pa(swapper_pg_dir) - PHYS_OFFSET;
 #endif
 	if (res_size)
 		reserve_bootmem_node(pgdat, PHYS_OFFSET, res_size);
 }

 void __init build_mem_type_table(void);
 void __init create_mapping(struct map_desc *md);

 static unsigned long __init
 bootmem_init_node(int node, int initrd_node, struct meminfo *mi)
 {
 	unsigned long zone_size[MAX_NR_ZONES], zhole_size[MAX_NR_ZONES];
 	unsigned long start_pfn, end_pfn, boot_pfn;
 	unsigned int boot_pages;
 	pg_data_t *pgdat;
 	int i;

 	start_pfn = -1UL;
 	end_pfn = 0;

 	/*
 	 * Calculate the pfn range, and map the memory banks for this node.
 	 */
 	for_each_nodebank(i, mi, node) {
 		unsigned long start, end;
 		struct map_desc map;

 		start = mi->bank[i].start >> PAGE_SHIFT;
 		end = (mi->bank[i].start + mi->bank[i].size) >> PAGE_SHIFT;

 		if (start_pfn > start)
 			start_pfn = start;
 		if (end_pfn < end)
 			end_pfn = end;

 		map.pfn = __phys_to_pfn(mi->bank[i].start);
 		map.virtual = __phys_to_virt(mi->bank[i].start);
 		map.length = mi->bank[i].size;
 		map.type = MT_MEMORY;

 		create_mapping(&map);
 	}

 	/*
 	 * If there is no memory in this node, ignore it.
 	 */
 	if (end_pfn == 0)
 		return end_pfn;

 	/*
 	 * Allocate the bootmem bitmap page.
 	 */
 	boot_pages = bootmem_bootmap_pages(end_pfn - start_pfn);
 	boot_pfn = find_bootmap_pfn(node, mi, boot_pages);

 	/*
 	 * Initialise the bootmem allocator for this node, handing the
 	 * memory banks over to bootmem.
 	 */
 	node_set_online(node);
 	pgdat = NODE_DATA(node);
 	init_bootmem_node(pgdat, boot_pfn, start_pfn, end_pfn);

 	for_each_nodebank(i, mi, node)
 		free_bootmem_node(pgdat, mi->bank[i].start, mi->bank[i].size);

 	/*
 	 * Reserve the bootmem bitmap for this node.
 	 */
 	reserve_bootmem_node(pgdat, boot_pfn << PAGE_SHIFT,
 			     boot_pages << PAGE_SHIFT);

 #ifdef CONFIG_BLK_DEV_INITRD
 	/*
 	 * If the initrd is in this node, reserve its memory.
 	 */
 	if (node == initrd_node) {
 		reserve_bootmem_node(pgdat, phys_initrd_start,
 				     phys_initrd_size);
 		initrd_start = __phys_to_virt(phys_initrd_start);
 		initrd_end = initrd_start + phys_initrd_size;
 	}
 #endif

 	/*
 	 * Finally, reserve any node zero regions.
 	 */
 	if (node == 0)
 		reserve_node_zero(pgdat);

 	/*
 	 * initialise the zones within this node.
 	 */
 	memset(zone_size, 0, sizeof(zone_size));
 	memset(zhole_size, 0, sizeof(zhole_size));

 	/*
 	 * The size of this node has already been determined.  If we need
 	 * to do anything fancy with the allocation of this memory to the
 	 * zones, now is the time to do it.
 	 */
 	zone_size[0] = end_pfn - start_pfn;

 	/*
 	 * For each bank in this node, calculate the size of the holes.
 	 *  holes = node_size - sum(bank_sizes_in_node)
 	 */
 	zhole_size[0] = zone_size[0];
 	for_each_nodebank(i, mi, node)
 		zhole_size[0] -= mi->bank[i].size >> PAGE_SHIFT;

 	/*
 	 * Adjust the sizes according to any special requirements for
 	 * this machine type.
 	 */
 	arch_adjust_zones(node, zone_size, zhole_size);

 	free_area_init_node(node, pgdat, zone_size, start_pfn, zhole_size);

 	return end_pfn;
 }

 static void __init bootmem_init(struct meminfo *mi)
 {
 	unsigned long addr, memend_pfn = 0;
 	int node, initrd_node, i;

 	/*
 	 * Invalidate the node number for empty or invalid memory banks
 	 */
 	for (i = 0; i < mi->nr_banks; i++)
 		if (mi->bank[i].size == 0 || mi->bank[i].node >= MAX_NUMNODES)
 			mi->bank[i].node = -1;

 	memcpy(&meminfo, mi, sizeof(meminfo));

 	/*
 	 * Clear out all the mappings below the kernel image.
 	 */
 	for (addr = 0; addr < MODULE_START; addr += PGDIR_SIZE)
 		pmd_clear(pmd_off_k(addr));
 #ifdef CONFIG_XIP_KERNEL
 	/* The XIP kernel is mapped in the module area -- skip over it */
 	addr = ((unsigned long)&_etext + PGDIR_SIZE - 1) & PGDIR_MASK;
 #endif
 	for ( ; addr < PAGE_OFFSET; addr += PGDIR_SIZE)
 		pmd_clear(pmd_off_k(addr));

 	/*
 	 * Clear out all the kernel space mappings, except for the first
 	 * memory bank, up to the end of the vmalloc region.
 	 */
 	for (addr = __phys_to_virt(mi->bank[0].start + mi->bank[0].size);
 	     addr < VMALLOC_END; addr += PGDIR_SIZE)
 		pmd_clear(pmd_off_k(addr));

 	/*
 	 * Locate which node contains the ramdisk image, if any.
 	 */
 	initrd_node = check_initrd(mi);

 	/*
 	 * Run through each node initialising the bootmem allocator.
 	 */
 	for_each_node(node) {
 		unsigned long end_pfn;

 		end_pfn = bootmem_init_node(node, initrd_node, mi);

 		/*
 		 * Remember the highest memory PFN.
 		 */
 		if (end_pfn > memend_pfn)
 			memend_pfn = end_pfn;
 	}

 	high_memory = __va(memend_pfn << PAGE_SHIFT);

 	/*
 	 * This doesn't seem to be used by the Linux memory manager any
 	 * more, but is used by ll_rw_block.  If we can get rid of it, we
 	 * also get rid of some of the stuff above as well.
 	 *
 	 * Note: max_low_pfn and max_pfn reflect the number of _pages_ in
 	 * the system, not the maximum PFN.
 	 */
 	max_pfn = max_low_pfn = memend_pfn - PHYS_PFN_OFFSET;
 }

 /*
  * Set up device the mappings.  Since we clear out the page tables for all
  * mappings above VMALLOC_END, we will remove any debug device mappings.
  * This means you have to be careful how you debug this function, or any
  * called function.  This means you can't use any function or debugging
  * method which may touch any device, otherwise the kernel _will_ crash.
  */
 static void __init devicemaps_init(struct machine_desc *mdesc)
 {
 	struct map_desc map;
 	unsigned long addr;
 	void *vectors;

 	/*
 	 * Allocate the vector page early.
 	 */
 	vectors = alloc_bootmem_low_pages(PAGE_SIZE);
 	BUG_ON(!vectors);

 	for (addr = VMALLOC_END; addr; addr += PGDIR_SIZE)
 		pmd_clear(pmd_off_k(addr));

 	/*
 	 * Map the kernel if it is XIP.
 	 * It is always first in the modulearea.
 	 */
 #ifdef CONFIG_XIP_KERNEL
 	map.pfn = __phys_to_pfn(CONFIG_XIP_PHYS_ADDR & PGDIR_MASK);
 	map.virtual = MODULE_START;
 	map.length = ((unsigned long)&_etext - map.virtual + ~PGDIR_MASK) & PGDIR_MASK;
 	map.type = MT_ROM;
 	create_mapping(&map);
 #endif

 	/*
 	 * Map the cache flushing regions.
 	 */
 #ifdef FLUSH_BASE
 	map.pfn = __phys_to_pfn(FLUSH_BASE_PHYS);
 	map.virtual = FLUSH_BASE;
 	map.length = PGDIR_SIZE;
 	map.type = MT_CACHECLEAN;
 	create_mapping(&map);
 #endif
 #ifdef FLUSH_BASE_MINICACHE
 	map.pfn = __phys_to_pfn(FLUSH_BASE_PHYS + PGDIR_SIZE);
 	map.virtual = FLUSH_BASE_MINICACHE;
 	map.length = PGDIR_SIZE;
 	map.type = MT_MINICLEAN;
 	create_mapping(&map);
 #endif

 	/*
 	 * Create a mapping for the machine vectors at the high-vectors
 	 * location (0xffff0000).  If we aren't using high-vectors, also
 	 * create a mapping at the low-vectors virtual address.
 	 */
 	map.pfn = __phys_to_pfn(virt_to_phys(vectors));
 	map.virtual = 0xffff0000;
 	map.length = PAGE_SIZE;
 	map.type = MT_HIGH_VECTORS;
 	create_mapping(&map);

 	if (!vectors_high()) {
 		map.virtual = 0;
 		map.type = MT_LOW_VECTORS;
 		create_mapping(&map);
 	}

 	/*
 	 * Ask the machine support to map in the statically mapped devices.
 	 */
 	if (mdesc->map_io)
 		mdesc->map_io();

 	/*
 	 * Finally flush the caches and tlb to ensure that we're in a
 	 * consistent state wrt the writebuffer.  This also ensures that
 	 * any write-allocated cache lines in the vector page are written
 	 * back.  After this point, we can start to touch devices again.
 	 */
 	local_flush_tlb_all();
 	flush_cache_all();
 }

 /*
  * paging_init() sets up the page tables, initialises the zone memory
  * maps, and sets up the zero page, bad page and bad page tables.
  */
 void __init paging_init(struct meminfo *mi, struct machine_desc *mdesc)
 {
 	void *zero_page;

 	build_mem_type_table();
 	bootmem_init(mi);
 	devicemaps_init(mdesc);

 	top_pmd = pmd_off_k(0xffff0000);

 	/*
 	 * allocate the zero page.  Note that we count on this going ok.
 	 */
 	zero_page = alloc_bootmem_low_pages(PAGE_SIZE);
 	memzero(zero_page, PAGE_SIZE);
 	empty_zero_page = virt_to_page(zero_page);
 	flush_dcache_page(empty_zero_page);
 }

 static inline void free_area(unsigned long addr, unsigned long end, char *s)
 {
 	unsigned int size = (end - addr) >> 10;

 	for (; addr < end; addr += PAGE_SIZE) {
 		struct page *page = virt_to_page(addr);
 		ClearPageReserved(page);
 		init_page_count(page);
 		free_page(addr);
 		totalram_pages++;
 	}

 	if (size && s)
 		printk(KERN_INFO "Freeing %s memory: %dK\n", s, size);
 }

 static inline void
 free_memmap(int node, unsigned long start_pfn, unsigned long end_pfn)
 {
 	struct page *start_pg, *end_pg;
 	unsigned long pg, pgend;

 	/*
 	 * Convert start_pfn/end_pfn to a struct page pointer.
 	 */
 	start_pg = pfn_to_page(start_pfn);
 	end_pg = pfn_to_page(end_pfn);

 	/*
 	 * Convert to physical addresses, and
 	 * round start upwards and end downwards.
 	 */
 	pg = PAGE_ALIGN(__pa(start_pg));
 	pgend = __pa(end_pg) & PAGE_MASK;

 	/*
 	 * If there are free pages between these,
 	 * free the section of the memmap array.
 	 */
 	if (pg < pgend)
 		free_bootmem_node(NODE_DATA(node), pg, pgend - pg);
 }

 /*
  * The mem_map array can get very big.  Free the unused area of the memory map.
  */
 static void __init free_unused_memmap_node(int node, struct meminfo *mi)
 {
 	unsigned long bank_start, prev_bank_end = 0;
 	unsigned int i;

 	/*
 	 * [FIXME] This relies on each bank being in address order.  This
 	 * may not be the case, especially if the user has provided the
 	 * information on the command line.
 	 */
 	for_each_nodebank(i, mi, node) {
 		bank_start = mi->bank[i].start >> PAGE_SHIFT;
 		if (bank_start < prev_bank_end) {
 			printk(KERN_ERR "MEM: unordered memory banks.  "
 				"Not freeing memmap.\n");
 			break;
 		}

 		/*
 		 * If we had a previous bank, and there is a space
 		 * between the current bank and the previous, free it.
 		 */
 		if (prev_bank_end && prev_bank_end != bank_start)
 			free_memmap(node, prev_bank_end, bank_start);

 		prev_bank_end = (mi->bank[i].start +
 				 mi->bank[i].size) >> PAGE_SHIFT;
 	}
 }

 /*
  * mem_init() marks the free areas in the mem_map and tells us how much
  * memory is free.  This is done after various parts of the system have
  * claimed their memory after the kernel image.
  */
 void __init mem_init(void)
 {
 	unsigned int codepages, datapages, initpages;
 	int i, node;

 	codepages = &_etext - &_text;
 	datapages = &_end - &__data_start;
 	initpages = &__init_end - &__init_begin;

 #ifndef CONFIG_DISCONTIGMEM
 	max_mapnr   = virt_to_page(high_memory) - mem_map;
 #endif

 	/* this will put all unused low memory onto the freelists */
 	for_each_online_node(node) {
 		pg_data_t *pgdat = NODE_DATA(node);

 		free_unused_memmap_node(node, &meminfo);

 		if (pgdat->node_spanned_pages != 0)
 			totalram_pages += free_all_bootmem_node(pgdat);
 	}

 #ifdef CONFIG_SA1111
 	/* now that our DMA memory is actually so designated, we can free it */
 	free_area(PAGE_OFFSET, (unsigned long)swapper_pg_dir, NULL);
 #endif

 	/*
 	 * Since our memory may not be contiguous, calculate the
 	 * real number of pages we have in this system
 	 */
 	printk(KERN_INFO "Memory:");

 	num_physpages = 0;
 	for (i = 0; i < meminfo.nr_banks; i++) {
 		num_physpages += meminfo.bank[i].size >> PAGE_SHIFT;
 		printk(" %ldMB", meminfo.bank[i].size >> 20);
 	}

 	printk(" = %luMB total\n", num_physpages >> (20 - PAGE_SHIFT));
 	printk(KERN_NOTICE "Memory: %luKB available (%dK code, "
 		"%dK data, %dK init)\n",
 		(unsigned long) nr_free_pages() << (PAGE_SHIFT-10),
 		codepages >> 10, datapages >> 10, initpages >> 10);

 	if (PAGE_SIZE >= 16384 && num_physpages <= 128) {
 		extern int sysctl_overcommit_memory;
 		/*
 		 * On a machine this small we won't get
 		 * anywhere without overcommit, so turn
 		 * it on by default.
 		 */
 		sysctl_overcommit_memory = OVERCOMMIT_ALWAYS;
 	}
 }

 void free_initmem(void)
 {
 	if (!machine_is_integrator() && !machine_is_cintegrator()) {
 		free_area((unsigned long)(&__init_begin),
 			  (unsigned long)(&__init_end),
 			  "init");
 	}
 }

 #ifdef CONFIG_BLK_DEV_INITRD

 static int keep_initrd;

 void free_initrd_mem(unsigned long start, unsigned long end)
 {
 	if (!keep_initrd)
 		free_area(start, end, "initrd");
 }

 static int __init keepinitrd_setup(char *__unused)
 {
 	keep_initrd = 1;
 	return 1;
 }

 __setup("keepinitrd", keepinitrd_setup);
 #endif
	/*
	* linux/arch/arm/mm/init.c
	*
	* Copyright (C) 1995-2005 Russell King
	*
	* 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.
	*/
	#include <linux/config.h>
	#include <linux/kernel.h>
	#include <linux/errno.h>
	#include <linux/ptrace.h>
	#include <linux/swap.h>
	#include <linux/init.h>
	#include <linux/bootmem.h>
	#include <linux/mman.h>
	#include <linux/nodemask.h>
	#include <linux/initrd.h>

	#include <asm/mach-types.h>
	#include <asm/setup.h>
	#include <asm/tlb.h>

	#include <asm/mach/arch.h>
	#include <asm/mach/map.h>

	#define TABLE_SIZE (2 * PTRS_PER_PTE * sizeof(pte_t))

	DEFINE_PER_CPU(struct mmu_gather, mmu_gathers);

	extern pgd_t swapper_pg_dir[PTRS_PER_PGD];
	extern void _stext, _text, _etext, __data_start, _end, __init_begin, __init_end;
	extern unsigned long phys_initrd_start;
	extern unsigned long phys_initrd_size;

	/*
	* The sole use of this is to pass memory configuration
	* data from paging_init to mem_init.
	*/
	static struct meminfo meminfo __initdata = { 0, };

	/*
	* empty_zero_page is a special page that is used for
	* zero-initialized data and COW.
	*/
	struct page *empty_zero_page;

	void show_mem(void)
	{
	int free = 0, total = 0, reserved = 0;
	int shared = 0, cached = 0, slab = 0, node;

	printk("Mem-info:\n");
	show_free_areas();
	printk("Free swap: %6ldkB\n", nr_swap_pages<<(PAGE_SHIFT-10));

	for_each_online_node(node) {
	struct page page, end;

	page = NODE_MEM_MAP(node);
	end = page + NODE_DATA(node)->node_spanned_pages;

	do {
	total++;
	if (PageReserved(page))
	reserved++;
	else if (PageSwapCache(page))
	cached++;
	else if (PageSlab(page))
	slab++;
	else if (!page_count(page))
	free++;
	else
	shared += page_count(page) - 1;
	page++;
	} while (page < end);
	}

	printk("%d pages of RAM\n", total);
	printk("%d free pages\n", free);
	printk("%d reserved pages\n", reserved);
	printk("%d slab pages\n", slab);
	printk("%d pages shared\n", shared);
	printk("%d pages swap cached\n", cached);
	}

	static inline pmd_t pmd_off(pgd_t pgd, unsigned long virt)
	{
	return pmd_offset(pgd, virt);
	}

	static inline pmd_t *pmd_off_k(unsigned long virt)
	{
	return pmd_off(pgd_offset_k(virt), virt);
	}

	#define for_each_nodebank(iter,mi,no) \
	for (iter = 0; iter < mi->nr_banks; iter++) \
	if (mi->bank[iter].node == no)

	/*
	* FIXME: We really want to avoid allocating the bootmap bitmap
	* over the top of the initrd. Hopefully, this is located towards
	* the start of a bank, so if we allocate the bootmap bitmap at
	* the end, we won't clash.
	*/
	static unsigned int __init
	find_bootmap_pfn(int node, struct meminfo *mi, unsigned int bootmap_pages)
	{
	unsigned int start_pfn, bank, bootmap_pfn;

	start_pfn = PAGE_ALIGN(__pa(&_end)) >> PAGE_SHIFT;
	bootmap_pfn = 0;

	for_each_nodebank(bank, mi, node) {
	unsigned int start, end;

	start = mi->bank[bank].start >> PAGE_SHIFT;
	end = (mi->bank[bank].size +
	mi->bank[bank].start) >> PAGE_SHIFT;

	if (end < start_pfn)
	continue;

	if (start < start_pfn)
	start = start_pfn;

	if (end <= start)
	continue;

	if (end - start >= bootmap_pages) {
	bootmap_pfn = start;
	break;
	}
	}

	if (bootmap_pfn == 0)
	BUG();

	return bootmap_pfn;
	}

	static int __init check_initrd(struct meminfo *mi)
	{
	int initrd_node = -2;
	#ifdef CONFIG_BLK_DEV_INITRD
	unsigned long end = phys_initrd_start + phys_initrd_size;

	/*
	* Make sure that the initrd is within a valid area of
	* memory.
	*/
	if (phys_initrd_size) {
	unsigned int i;

	initrd_node = -1;

	for (i = 0; i < mi->nr_banks; i++) {
	unsigned long bank_end;

	bank_end = mi->bank[i].start + mi->bank[i].size;

	if (mi->bank[i].start <= phys_initrd_start &&
	end <= bank_end)
	initrd_node = mi->bank[i].node;
	}
	}

	if (initrd_node == -1) {
	printk(KERN_ERR "initrd (0x%08lx - 0x%08lx) extends beyond "
	"physical memory - disabling initrd\n",
	phys_initrd_start, end);
	phys_initrd_start = phys_initrd_size = 0;
	}
	#endif

	return initrd_node;
	}

	/*
	* Reserve the various regions of node 0
	*/
	static __init void reserve_node_zero(pg_data_t *pgdat)
	{
	unsigned long res_size = 0;

	/*
	* Register the kernel text and data with bootmem.
	* Note that this can only be in node 0.
	*/
	#ifdef CONFIG_XIP_KERNEL
	reserve_bootmem_node(pgdat, __pa(&__data_start), &_end - &__data_start);
	#else
	reserve_bootmem_node(pgdat, __pa(&_stext), &_end - &_stext);
	#endif

	/*
	* Reserve the page tables. These are already in use,
	* and can only be in node 0.
	*/
	reserve_bootmem_node(pgdat, __pa(swapper_pg_dir),
	PTRS_PER_PGD * sizeof(pgd_t));

	/*
	* Hmm... This should go elsewhere, but we really really need to
	* stop things allocating the low memory; ideally we need a better
	* implementation of GFP_DMA which does not assume that DMA-able
	* memory starts at zero.
	*/
	if (machine_is_integrator() \|\| machine_is_cintegrator())
	res_size = __pa(swapper_pg_dir) - PHYS_OFFSET;

	/*
	* These should likewise go elsewhere. They pre-reserve the
	* screen memory region at the start of main system memory.
	*/
	if (machine_is_edb7211())
	res_size = 0x00020000;
	if (machine_is_p720t())
	res_size = 0x00014000;

	#ifdef CONFIG_SA1111
	/*
	* Because of the SA1111 DMA bug, we want to preserve our
	* precious DMA-able memory...
	*/
	res_size = __pa(swapper_pg_dir) - PHYS_OFFSET;
	#endif
	if (res_size)
	reserve_bootmem_node(pgdat, PHYS_OFFSET, res_size);
	}

	void __init build_mem_type_table(void);
	void __init create_mapping(struct map_desc *md);

	static unsigned long __init
	bootmem_init_node(int node, int initrd_node, struct meminfo *mi)
	{
	unsigned long zone_size[MAX_NR_ZONES], zhole_size[MAX_NR_ZONES];
	unsigned long start_pfn, end_pfn, boot_pfn;
	unsigned int boot_pages;
	pg_data_t *pgdat;
	int i;

	start_pfn = -1UL;
	end_pfn = 0;

	/*
	* Calculate the pfn range, and map the memory banks for this node.
	*/
	for_each_nodebank(i, mi, node) {
	unsigned long start, end;
	struct map_desc map;

	start = mi->bank[i].start >> PAGE_SHIFT;
	end = (mi->bank[i].start + mi->bank[i].size) >> PAGE_SHIFT;

	if (start_pfn > start)
	start_pfn = start;
	if (end_pfn < end)
	end_pfn = end;

	map.pfn = __phys_to_pfn(mi->bank[i].start);
	map.virtual = __phys_to_virt(mi->bank[i].start);
	map.length = mi->bank[i].size;
	map.type = MT_MEMORY;

	create_mapping(&map);
	}

	/*
	* If there is no memory in this node, ignore it.
	*/
	if (end_pfn == 0)
	return end_pfn;

	/*
	* Allocate the bootmem bitmap page.
	*/
	boot_pages = bootmem_bootmap_pages(end_pfn - start_pfn);
	boot_pfn = find_bootmap_pfn(node, mi, boot_pages);

	/*
	* Initialise the bootmem allocator for this node, handing the
	* memory banks over to bootmem.
	*/
	node_set_online(node);
	pgdat = NODE_DATA(node);
	init_bootmem_node(pgdat, boot_pfn, start_pfn, end_pfn);

	for_each_nodebank(i, mi, node)
	free_bootmem_node(pgdat, mi->bank[i].start, mi->bank[i].size);

	/*
	* Reserve the bootmem bitmap for this node.
	*/
	reserve_bootmem_node(pgdat, boot_pfn << PAGE_SHIFT,
	boot_pages << PAGE_SHIFT);

	#ifdef CONFIG_BLK_DEV_INITRD
	/*
	* If the initrd is in this node, reserve its memory.
	*/
	if (node == initrd_node) {
	reserve_bootmem_node(pgdat, phys_initrd_start,
	phys_initrd_size);
	initrd_start = __phys_to_virt(phys_initrd_start);
	initrd_end = initrd_start + phys_initrd_size;
	}
	#endif

	/*
	* Finally, reserve any node zero regions.
	*/
	if (node == 0)
	reserve_node_zero(pgdat);

	/*
	* initialise the zones within this node.
	*/
	memset(zone_size, 0, sizeof(zone_size));
	memset(zhole_size, 0, sizeof(zhole_size));

	/*
	* The size of this node has already been determined. If we need
	* to do anything fancy with the allocation of this memory to the
	* zones, now is the time to do it.
	*/
	zone_size[0] = end_pfn - start_pfn;

	/*
	* For each bank in this node, calculate the size of the holes.
	* holes = node_size - sum(bank_sizes_in_node)
	*/
	zhole_size[0] = zone_size[0];
	for_each_nodebank(i, mi, node)
	zhole_size[0] -= mi->bank[i].size >> PAGE_SHIFT;

	/*
	* Adjust the sizes according to any special requirements for
	* this machine type.
	*/
	arch_adjust_zones(node, zone_size, zhole_size);

	free_area_init_node(node, pgdat, zone_size, start_pfn, zhole_size);

	return end_pfn;
	}

	static void __init bootmem_init(struct meminfo *mi)
	{
	unsigned long addr, memend_pfn = 0;
	int node, initrd_node, i;

	/*
	* Invalidate the node number for empty or invalid memory banks
	*/
	for (i = 0; i < mi->nr_banks; i++)
	if (mi->bank[i].size == 0 \|\| mi->bank[i].node >= MAX_NUMNODES)
	mi->bank[i].node = -1;

	memcpy(&meminfo, mi, sizeof(meminfo));

	/*
	* Clear out all the mappings below the kernel image.
	*/
	for (addr = 0; addr < MODULE_START; addr += PGDIR_SIZE)
	pmd_clear(pmd_off_k(addr));
	#ifdef CONFIG_XIP_KERNEL
	/* The XIP kernel is mapped in the module area -- skip over it */
	addr = ((unsigned long)&_etext + PGDIR_SIZE - 1) & PGDIR_MASK;
	#endif
	for ( ; addr < PAGE_OFFSET; addr += PGDIR_SIZE)
	pmd_clear(pmd_off_k(addr));

	/*
	* Clear out all the kernel space mappings, except for the first
	* memory bank, up to the end of the vmalloc region.
	*/
	for (addr = __phys_to_virt(mi->bank[0].start + mi->bank[0].size);
	addr < VMALLOC_END; addr += PGDIR_SIZE)
	pmd_clear(pmd_off_k(addr));

	/*
	* Locate which node contains the ramdisk image, if any.
	*/
	initrd_node = check_initrd(mi);

	/*
	* Run through each node initialising the bootmem allocator.
	*/
	for_each_node(node) {
	unsigned long end_pfn;

	end_pfn = bootmem_init_node(node, initrd_node, mi);

	/*
	* Remember the highest memory PFN.
	*/
	if (end_pfn > memend_pfn)
	memend_pfn = end_pfn;
	}

	high_memory = __va(memend_pfn << PAGE_SHIFT);

	/*
	* This doesn't seem to be used by the Linux memory manager any
	* more, but is used by ll_rw_block. If we can get rid of it, we
	* also get rid of some of the stuff above as well.
	*
	* Note: max_low_pfn and max_pfn reflect the number of _pages_ in
	* the system, not the maximum PFN.
	*/
	max_pfn = max_low_pfn = memend_pfn - PHYS_PFN_OFFSET;
	}

	/*
	* Set up device the mappings. Since we clear out the page tables for all
	* mappings above VMALLOC_END, we will remove any debug device mappings.
	* This means you have to be careful how you debug this function, or any
	* called function. This means you can't use any function or debugging
	* method which may touch any device, otherwise the kernel _will_ crash.
	*/
	static void __init devicemaps_init(struct machine_desc *mdesc)
	{
	struct map_desc map;
	unsigned long addr;
	void *vectors;

	/*
	* Allocate the vector page early.
	*/
	vectors = alloc_bootmem_low_pages(PAGE_SIZE);
	BUG_ON(!vectors);

	for (addr = VMALLOC_END; addr; addr += PGDIR_SIZE)
	pmd_clear(pmd_off_k(addr));

	/*
	* Map the kernel if it is XIP.
	* It is always first in the modulearea.
	*/
	#ifdef CONFIG_XIP_KERNEL
	map.pfn = __phys_to_pfn(CONFIG_XIP_PHYS_ADDR & PGDIR_MASK);
	map.virtual = MODULE_START;
	map.length = ((unsigned long)&_etext - map.virtual + ~PGDIR_MASK) & PGDIR_MASK;
	map.type = MT_ROM;
	create_mapping(&map);
	#endif

	/*
	* Map the cache flushing regions.
	*/
	#ifdef FLUSH_BASE
	map.pfn = __phys_to_pfn(FLUSH_BASE_PHYS);
	map.virtual = FLUSH_BASE;
	map.length = PGDIR_SIZE;
	map.type = MT_CACHECLEAN;
	create_mapping(&map);
	#endif
	#ifdef FLUSH_BASE_MINICACHE
	map.pfn = __phys_to_pfn(FLUSH_BASE_PHYS + PGDIR_SIZE);
	map.virtual = FLUSH_BASE_MINICACHE;
	map.length = PGDIR_SIZE;
	map.type = MT_MINICLEAN;
	create_mapping(&map);
	#endif

	/*
	* Create a mapping for the machine vectors at the high-vectors
	* location (0xffff0000). If we aren't using high-vectors, also
	* create a mapping at the low-vectors virtual address.
	*/
	map.pfn = __phys_to_pfn(virt_to_phys(vectors));
	map.virtual = 0xffff0000;
	map.length = PAGE_SIZE;
	map.type = MT_HIGH_VECTORS;
	create_mapping(&map);

	if (!vectors_high()) {
	map.virtual = 0;
	map.type = MT_LOW_VECTORS;
	create_mapping(&map);
	}

	/*
	* Ask the machine support to map in the statically mapped devices.
	*/
	if (mdesc->map_io)
	mdesc->map_io();

	/*
	* Finally flush the caches and tlb to ensure that we're in a
	* consistent state wrt the writebuffer. This also ensures that
	* any write-allocated cache lines in the vector page are written
	* back. After this point, we can start to touch devices again.
	*/
	local_flush_tlb_all();
	flush_cache_all();
	}

	/*
	* paging_init() sets up the page tables, initialises the zone memory
	* maps, and sets up the zero page, bad page and bad page tables.
	*/
	void __init paging_init(struct meminfo mi, struct machine_desc mdesc)
	{
	void *zero_page;

	build_mem_type_table();
	bootmem_init(mi);
	devicemaps_init(mdesc);

	top_pmd = pmd_off_k(0xffff0000);

	/*
	* allocate the zero page. Note that we count on this going ok.
	*/
	zero_page = alloc_bootmem_low_pages(PAGE_SIZE);
	memzero(zero_page, PAGE_SIZE);
	empty_zero_page = virt_to_page(zero_page);
	flush_dcache_page(empty_zero_page);
	}

	static inline void free_area(unsigned long addr, unsigned long end, char *s)
	{
	unsigned int size = (end - addr) >> 10;

	for (; addr < end; addr += PAGE_SIZE) {
	struct page *page = virt_to_page(addr);
	ClearPageReserved(page);
	init_page_count(page);
	free_page(addr);
	totalram_pages++;
	}

	if (size && s)
	printk(KERN_INFO "Freeing %s memory: %dK\n", s, size);
	}

	static inline void
	free_memmap(int node, unsigned long start_pfn, unsigned long end_pfn)
	{
	struct page start_pg, end_pg;
	unsigned long pg, pgend;

	/*
	* Convert start_pfn/end_pfn to a struct page pointer.
	*/
	start_pg = pfn_to_page(start_pfn);
	end_pg = pfn_to_page(end_pfn);

	/*
	* Convert to physical addresses, and
	* round start upwards and end downwards.
	*/
	pg = PAGE_ALIGN(__pa(start_pg));
	pgend = __pa(end_pg) & PAGE_MASK;

	/*
	* If there are free pages between these,
	* free the section of the memmap array.
	*/
	if (pg < pgend)
	free_bootmem_node(NODE_DATA(node), pg, pgend - pg);
	}

	/*
	* The mem_map array can get very big. Free the unused area of the memory map.
	*/
	static void __init free_unused_memmap_node(int node, struct meminfo *mi)
	{
	unsigned long bank_start, prev_bank_end = 0;
	unsigned int i;

	/*
	* [FIXME] This relies on each bank being in address order. This
	* may not be the case, especially if the user has provided the
	* information on the command line.
	*/
	for_each_nodebank(i, mi, node) {
	bank_start = mi->bank[i].start >> PAGE_SHIFT;
	if (bank_start < prev_bank_end) {
	printk(KERN_ERR "MEM: unordered memory banks. "
	"Not freeing memmap.\n");
	break;
	}

	/*
	* If we had a previous bank, and there is a space
	* between the current bank and the previous, free it.
	*/
	if (prev_bank_end && prev_bank_end != bank_start)
	free_memmap(node, prev_bank_end, bank_start);

	prev_bank_end = (mi->bank[i].start +
	mi->bank[i].size) >> PAGE_SHIFT;
	}
	}

	/*
	* mem_init() marks the free areas in the mem_map and tells us how much
	* memory is free. This is done after various parts of the system have
	* claimed their memory after the kernel image.
	*/
	void __init mem_init(void)
	{
	unsigned int codepages, datapages, initpages;
	int i, node;

	codepages = &_etext - &_text;
	datapages = &_end - &__data_start;
	initpages = &__init_end - &__init_begin;

	#ifndef CONFIG_DISCONTIGMEM
	max_mapnr = virt_to_page(high_memory) - mem_map;
	#endif

	/* this will put all unused low memory onto the freelists */
	for_each_online_node(node) {
	pg_data_t *pgdat = NODE_DATA(node);

	free_unused_memmap_node(node, &meminfo);

	if (pgdat->node_spanned_pages != 0)
	totalram_pages += free_all_bootmem_node(pgdat);
	}

	#ifdef CONFIG_SA1111
	/* now that our DMA memory is actually so designated, we can free it */
	free_area(PAGE_OFFSET, (unsigned long)swapper_pg_dir, NULL);
	#endif

	/*
	* Since our memory may not be contiguous, calculate the
	* real number of pages we have in this system
	*/
	printk(KERN_INFO "Memory:");

	num_physpages = 0;
	for (i = 0; i < meminfo.nr_banks; i++) {
	num_physpages += meminfo.bank[i].size >> PAGE_SHIFT;
	printk(" %ldMB", meminfo.bank[i].size >> 20);
	}

	printk(" = %luMB total\n", num_physpages >> (20 - PAGE_SHIFT));
	printk(KERN_NOTICE "Memory: %luKB available (%dK code, "
	"%dK data, %dK init)\n",
	(unsigned long) nr_free_pages() << (PAGE_SHIFT-10),
	codepages >> 10, datapages >> 10, initpages >> 10);

	if (PAGE_SIZE >= 16384 && num_physpages <= 128) {
	extern int sysctl_overcommit_memory;
	/*
	* On a machine this small we won't get
	* anywhere without overcommit, so turn
	* it on by default.
	*/
	sysctl_overcommit_memory = OVERCOMMIT_ALWAYS;
	}
	}

	void free_initmem(void)
	{
	if (!machine_is_integrator() && !machine_is_cintegrator()) {
	free_area((unsigned long)(&__init_begin),
	(unsigned long)(&__init_end),
	"init");
	}
	}

	#ifdef CONFIG_BLK_DEV_INITRD

	static int keep_initrd;

	void free_initrd_mem(unsigned long start, unsigned long end)
	{
	if (!keep_initrd)
	free_area(start, end, "initrd");
	}

	static int __init keepinitrd_setup(char *__unused)
	{
	keep_initrd = 1;
	return 1;
	}

	__setup("keepinitrd", keepinitrd_setup);
	#endif