init.c

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/*
 *  linux/arch/arm/mm/init.c
 *
 *  Copyright (C) 1995-2002 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/hardware.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);
}

struct node_info {
	unsigned int start;
	unsigned int end;
	int bootmap_pages;
};

#define O_PFN_DOWN(x)	((x) >> PAGE_SHIFT)
#define O_PFN_UP(x)	(PAGE_ALIGN(x) >> PAGE_SHIFT)

/*
 * 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   = O_PFN_UP(__pa(&_end));
	bootmap_pfn = 0;

	for (bank = 0; bank < mi->nr_banks; bank ++) {
		unsigned int start, end;

		if (mi->bank[bank].node != node)
			continue;

		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;
}

/*
 * Scan the memory info structure and pull out:
 *  - the end of memory
 *  - the number of nodes
 *  - the pfn range of each node
 *  - the number of bootmem bitmap pages
 */
static unsigned int __init
find_memend_and_nodes(struct meminfo *mi, struct node_info *np)
{
	unsigned int i, bootmem_pages = 0, memend_pfn = 0;

	for (i = 0; i < MAX_NUMNODES; i++) {
		np[i].start = -1U;
		np[i].end = 0;
		np[i].bootmap_pages = 0;
	}

	for (i = 0; i < mi->nr_banks; i++) {
		unsigned long start, end;
		int node;

		if (mi->bank[i].size == 0) {
			/*
			 * Mark this bank with an invalid node number
			 */
			mi->bank[i].node = -1;
			continue;
		}

		node = mi->bank[i].node;

		/*
		 * Make sure we haven't exceeded the maximum number of nodes
		 * that we have in this configuration.  If we have, we're in
		 * trouble.  (maybe we ought to limit, instead of bugging?)
		 */
		if (node >= MAX_NUMNODES)
			BUG();
		node_set_online(node);

		/*
		 * Get the start and end pfns for this bank
		 */
		start = mi->bank[i].start >> PAGE_SHIFT;
		end   = (mi->bank[i].start + mi->bank[i].size) >> PAGE_SHIFT;

		if (np[node].start > start)
			np[node].start = start;

		if (np[node].end < end)
			np[node].end = end;

		if (memend_pfn < end)
			memend_pfn = end;
	}

	/*
	 * Calculate the number of pages we require to
	 * store the bootmem bitmaps.
	 */
	for_each_online_node(i) {
		if (np[i].end == 0)
			continue;

		np[i].bootmap_pages = bootmem_bootmap_pages(np[i].end -
							    np[i].start);
		bootmem_pages += np[i].bootmap_pages;
	}

	high_memory = __va(memend_pfn << PAGE_SHIFT);

	/*
	 * This doesn't seem to be used by the Linux memory
	 * manager any more.  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_low_pfn = memend_pfn - O_PFN_DOWN(PHYS_OFFSET);
	max_pfn = memend_pfn - O_PFN_DOWN(PHYS_OFFSET);

	return bootmem_pages;
}

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(unsigned int bootmap_pfn, unsigned int bootmap_pages)
{
	pg_data_t *pgdat = NODE_DATA(0);
	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));

	/*
	 * And don't forget to reserve the allocator bitmap,
	 * which will be freed later.
	 */
	reserve_bootmem_node(pgdat, bootmap_pfn << PAGE_SHIFT,
			     bootmap_pages << PAGE_SHIFT);

	/*
	 * 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);
}

/*
 * Register all available RAM in this node with the bootmem allocator.
 */
static inline void free_bootmem_node_bank(int node, struct meminfo *mi)
{
	pg_data_t *pgdat = NODE_DATA(node);
	int bank;

	for (bank = 0; bank < mi->nr_banks; bank++)
		if (mi->bank[bank].node == node)
			free_bootmem_node(pgdat, mi->bank[bank].start,
					  mi->bank[bank].size);
}