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Sourcecode: linux-2.6 version File versions

init.c

/*
 *  linux/arch/arm26/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/signal.h>
#include <linux/sched.h>
#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/string.h>
#include <linux/types.h>
#include <linux/ptrace.h>
#include <linux/mman.h>
#include <linux/mm.h>
#include <linux/swap.h>
#include <linux/smp.h>
#include <linux/init.h>
#include <linux/initrd.h>
#include <linux/bootmem.h>
#include <linux/blkdev.h>
#include <linux/pfn.h>

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

#include <asm/map.h>


#define TABLE_SIZE      PTRS_PER_PTE * sizeof(pte_t))

struct mmu_gather mmu_gathers[NR_CPUS];

extern pgd_t swapper_pg_dir[PTRS_PER_PGD];
extern char _stext, _text, _etext, _end, __init_begin, __init_end;
#ifdef CONFIG_XIP_KERNEL
extern char _endtext, _sdata;
#endif
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;
      struct page *page, *end;

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


      page = NODE_MEM_MAP(0);
      end  = page + NODE_DATA(0)->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;
};

/*
 * 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(struct meminfo *mi, unsigned int bootmap_pages)
{
      unsigned int start_pfn, bootmap_pfn;
      unsigned int start, end;

      start_pfn   = PFN_UP((unsigned long)&_end);
      bootmap_pfn = 0;

      /* ARM26 machines only have one node */
      if (mi->bank->node != 0)
            BUG();

      start = PFN_UP(mi->bank->start);
      end   = PFN_DOWN(mi->bank->size + mi->bank->start);

      if (start < start_pfn)
            start = start_pfn;

      if (end <= start)
            BUG();

      if (end - start >= bootmap_pages) 
            bootmap_pfn = start;
      else
            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 void __init
find_memend_and_nodes(struct meminfo *mi, struct node_info *np)
{
      unsigned int memend_pfn = 0;

      nodes_clear(node_online_map);
      node_set_online(0);

      np->bootmap_pages = 0;

      if (mi->bank->size == 0) {
            BUG();
      }

      /*
       * Get the start and end pfns for this bank
       */
      np->start = PFN_UP(mi->bank->start);
      np->end   = PFN_DOWN(mi->bank->start + mi->bank->size);

      if (memend_pfn < np->end)
            memend_pfn = np->end;

      /*
       * Calculate the number of pages we require to
       * store the bootmem bitmaps.
       */
      np->bootmap_pages = bootmem_bootmap_pages(np->end - np->start);

      /*
       * 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.
       */
      max_low_pfn = memend_pfn - PFN_DOWN(PHYS_OFFSET);
      max_pfn = memend_pfn - PFN_DOWN(PHYS_OFFSET);
      mi->end = memend_pfn << PAGE_SHIFT;

}

/*
 * Initialise the bootmem allocator for all nodes.  This is called
 * early during the architecture specific initialisation.
 */
void __init bootmem_init(struct meminfo *mi)
{
      struct node_info node_info;
      unsigned int bootmap_pfn;
      pg_data_t *pgdat = NODE_DATA(0);

      find_memend_and_nodes(mi, &node_info);

      bootmap_pfn   = find_bootmap_pfn(mi, node_info.bootmap_pages);

      /*
       * Note that node 0 must always have some pages.
       */
      if (node_info.end == 0)
            BUG();

      /*
       * Initialise the bootmem allocator.
       */
      init_bootmem_node(pgdat, bootmap_pfn, node_info.start, node_info.end);

      /*
       * Register all available RAM in this node with the bootmem allocator. 
       */
      free_bootmem_node(pgdat, mi->bank->start, mi->bank->size);

        /*
         * Register the kernel text and data with bootmem.
         * Note: with XIP we dont register .text since
         * its in ROM.
         */
#ifdef CONFIG_XIP_KERNEL
        reserve_bootmem_node(pgdat, __pa(&_sdata), &_end - &_sdata);
#else
        reserve_bootmem_node(pgdat, __pa(&_stext), &_end - &_stext);
#endif

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

        /*
         * These should likewise go elsewhere.  They pre-reserve
         * the screen memory region at the start of main system
         * memory. FIXME - screen RAM is not 512K!
         */
        reserve_bootmem_node(pgdat, 0x02000000, 0x00080000);

#ifdef CONFIG_BLK_DEV_INITRD
        initrd_start = phys_initrd_start;
        initrd_end = initrd_start + phys_initrd_size;

        /* Achimedes machines only have one node, so initrd is in node 0 */
#ifdef CONFIG_XIP_KERNEL
      /* Only reserve initrd space if it is in RAM */
        if(initrd_start && initrd_start < 0x03000000){
#else
        if(initrd_start){
#endif
                reserve_bootmem_node(pgdat, __pa(initrd_start),
                                             initrd_end - initrd_start);
      }
#endif   /* CONFIG_BLK_DEV_INITRD */


}

/*
 * 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)
{
      void *zero_page;
      unsigned long zone_size[MAX_NR_ZONES];
        unsigned long zhole_size[MAX_NR_ZONES];
        struct bootmem_data *bdata;
        pg_data_t *pgdat;
      int i;

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

      /*
       * allocate the zero page.  Note that we count on this going ok.
       */
      zero_page = alloc_bootmem_low_pages(PAGE_SIZE);

      /*
       * initialise the page tables.
       */
      memtable_init(mi);
      flush_tlb_all();

      /*
       * initialise the zones in node 0 (archimedes have only 1 node)
       */

      for (i = 0; i < MAX_NR_ZONES; i++) {
            zone_size[i]  = 0;
            zhole_size[i] = 0;
      }

      pgdat = NODE_DATA(0);
      bdata = pgdat->bdata;
      zone_size[0] = bdata->node_low_pfn -
                  (bdata->node_boot_start >> PAGE_SHIFT);
      if (!zone_size[0])
            BUG();
      pgdat->node_mem_map = NULL;
      free_area_init_node(0, pgdat, zone_size,
                  bdata->node_boot_start >> PAGE_SHIFT, zhole_size);

      /*
       * finish off the bad pages once
       * the mem_map is initialised
       */
      memzero(zero_page, PAGE_SIZE);
      empty_zero_page = virt_to_page(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);
}

/*
 * 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;
      pg_data_t *pgdat = NODE_DATA(0);
      extern int sysctl_overcommit_memory;


      /* Note: data pages includes BSS */
#ifdef CONFIG_XIP_KERNEL
      codepages = &_endtext - &_text;
      datapages = &_end - &_sdata;
#else
      codepages = &_etext - &_text;
      datapages = &_end - &_etext;
#endif
      initpages = &__init_end - &__init_begin;

      high_memory = (void *)__va(meminfo.end);
      max_mapnr   = virt_to_page(high_memory) - mem_map;

      /* this will put all unused low memory onto the freelists */
      if (pgdat->node_spanned_pages != 0)
            totalram_pages += free_all_bootmem_node(pgdat);

      num_physpages = meminfo.bank[0].size >> PAGE_SHIFT;

      printk(KERN_INFO "Memory: %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);

      /*
       * Turn on overcommit on tiny machines
       */
      if (PAGE_SIZE >= 16384 && num_physpages <= 128) {
            sysctl_overcommit_memory = OVERCOMMIT_ALWAYS;
            printk("Turning on overcommit\n");
      }
}

void free_initmem(void){
#ifndef CONFIG_XIP_KERNEL
      free_area((unsigned long)(&__init_begin),
              (unsigned long)(&__init_end),
              "init");
#endif
}

#ifdef CONFIG_BLK_DEV_INITRD

static int keep_initrd;

void free_initrd_mem(unsigned long start, unsigned long end)
{
#ifdef CONFIG_XIP_KERNEL
      /* Only bin initrd if it is in RAM... */
      if(!keep_initrd && start < 0x03000000)
#else
      if (!keep_initrd)
#endif
            free_area(start, end, "initrd");
}

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

__setup("keepinitrd", keepinitrd_setup);
#endif

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