linux/arch/m68knommu/mm/init.c
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   1/*
   2 *  linux/arch/m68knommu/mm/init.c
   3 *
   4 *  Copyright (C) 1998  D. Jeff Dionne <jeff@lineo.ca>,
   5 *                      Kenneth Albanowski <kjahds@kjahds.com>,
   6 *  Copyright (C) 2000  Lineo, Inc.  (www.lineo.com) 
   7 *
   8 *  Based on:
   9 *
  10 *  linux/arch/m68k/mm/init.c
  11 *
  12 *  Copyright (C) 1995  Hamish Macdonald
  13 *
  14 *  JAN/1999 -- hacked to support ColdFire (gerg@snapgear.com)
  15 *  DEC/2000 -- linux 2.4 support <davidm@snapgear.com>
  16 */
  17
  18#include <linux/signal.h>
  19#include <linux/sched.h>
  20#include <linux/kernel.h>
  21#include <linux/errno.h>
  22#include <linux/string.h>
  23#include <linux/types.h>
  24#include <linux/ptrace.h>
  25#include <linux/mman.h>
  26#include <linux/mm.h>
  27#include <linux/swap.h>
  28#include <linux/init.h>
  29#include <linux/highmem.h>
  30#include <linux/pagemap.h>
  31#include <linux/bootmem.h>
  32#include <linux/slab.h>
  33
  34#include <asm/setup.h>
  35#include <asm/segment.h>
  36#include <asm/page.h>
  37#include <asm/pgtable.h>
  38#include <asm/system.h>
  39#include <asm/machdep.h>
  40
  41#undef DEBUG
  42
  43extern void die_if_kernel(char *,struct pt_regs *,long);
  44extern void free_initmem(void);
  45
  46/*
  47 * BAD_PAGE is the page that is used for page faults when linux
  48 * is out-of-memory. Older versions of linux just did a
  49 * do_exit(), but using this instead means there is less risk
  50 * for a process dying in kernel mode, possibly leaving a inode
  51 * unused etc..
  52 *
  53 * BAD_PAGETABLE is the accompanying page-table: it is initialized
  54 * to point to BAD_PAGE entries.
  55 *
  56 * ZERO_PAGE is a special page that is used for zero-initialized
  57 * data and COW.
  58 */
  59static unsigned long empty_bad_page_table;
  60
  61static unsigned long empty_bad_page;
  62
  63unsigned long empty_zero_page;
  64
  65extern unsigned long memory_start;
  66extern unsigned long memory_end;
  67
  68/*
  69 * paging_init() continues the virtual memory environment setup which
  70 * was begun by the code in arch/head.S.
  71 * The parameters are pointers to where to stick the starting and ending
  72 * addresses of available kernel virtual memory.
  73 */
  74void __init paging_init(void)
  75{
  76        /*
  77         * Make sure start_mem is page aligned, otherwise bootmem and
  78         * page_alloc get different views of the world.
  79         */
  80#ifdef DEBUG
  81        unsigned long start_mem = PAGE_ALIGN(memory_start);
  82#endif
  83        unsigned long end_mem   = memory_end & PAGE_MASK;
  84
  85#ifdef DEBUG
  86        printk (KERN_DEBUG "start_mem is %#lx\nvirtual_end is %#lx\n",
  87                start_mem, end_mem);
  88#endif
  89
  90        /*
  91         * Initialize the bad page table and bad page to point
  92         * to a couple of allocated pages.
  93         */
  94        empty_bad_page_table = (unsigned long)alloc_bootmem_pages(PAGE_SIZE);
  95        empty_bad_page = (unsigned long)alloc_bootmem_pages(PAGE_SIZE);
  96        empty_zero_page = (unsigned long)alloc_bootmem_pages(PAGE_SIZE);
  97        memset((void *)empty_zero_page, 0, PAGE_SIZE);
  98
  99        /*
 100         * Set up SFC/DFC registers (user data space).
 101         */
 102        set_fs (USER_DS);
 103
 104#ifdef DEBUG
 105        printk (KERN_DEBUG "before free_area_init\n");
 106
 107        printk (KERN_DEBUG "free_area_init -> start_mem is %#lx\nvirtual_end is %#lx\n",
 108                start_mem, end_mem);
 109#endif
 110
 111        {
 112                unsigned long zones_size[MAX_NR_ZONES] = {0, };
 113
 114                zones_size[ZONE_DMA] = 0 >> PAGE_SHIFT;
 115                zones_size[ZONE_NORMAL] = (end_mem - PAGE_OFFSET) >> PAGE_SHIFT;
 116#ifdef CONFIG_HIGHMEM
 117                zones_size[ZONE_HIGHMEM] = 0;
 118#endif
 119                free_area_init(zones_size);
 120        }
 121}
 122
 123void __init mem_init(void)
 124{
 125        int codek = 0, datak = 0, initk = 0;
 126        unsigned long tmp;
 127        extern char _etext, _stext, _sdata, _ebss, __init_begin, __init_end;
 128        extern unsigned int _ramend, _rambase;
 129        unsigned long len = _ramend - _rambase;
 130        unsigned long start_mem = memory_start; /* DAVIDM - these must start at end of kernel */
 131        unsigned long end_mem   = memory_end; /* DAVIDM - this must not include kernel stack at top */
 132
 133#ifdef DEBUG
 134        printk(KERN_DEBUG "Mem_init: start=%lx, end=%lx\n", start_mem, end_mem);
 135#endif
 136
 137        end_mem &= PAGE_MASK;
 138        high_memory = (void *) end_mem;
 139
 140        start_mem = PAGE_ALIGN(start_mem);
 141        max_mapnr = num_physpages = (((unsigned long) high_memory) - PAGE_OFFSET) >> PAGE_SHIFT;
 142
 143        /* this will put all memory onto the freelists */
 144        totalram_pages = free_all_bootmem();
 145
 146        codek = (&_etext - &_stext) >> 10;
 147        datak = (&_ebss - &_sdata) >> 10;
 148        initk = (&__init_begin - &__init_end) >> 10;
 149
 150        tmp = nr_free_pages() << PAGE_SHIFT;
 151        printk(KERN_INFO "Memory available: %luk/%luk RAM, (%dk kernel code, %dk data)\n",
 152               tmp >> 10,
 153               len >> 10,
 154               codek,
 155               datak
 156               );
 157}
 158
 159
 160#ifdef CONFIG_BLK_DEV_INITRD
 161void free_initrd_mem(unsigned long start, unsigned long end)
 162{
 163        int pages = 0;
 164        for (; start < end; start += PAGE_SIZE) {
 165                ClearPageReserved(virt_to_page(start));
 166                init_page_count(virt_to_page(start));
 167                free_page(start);
 168                totalram_pages++;
 169                pages++;
 170        }
 171        printk (KERN_NOTICE "Freeing initrd memory: %dk freed\n", pages);
 172}
 173#endif
 174
 175void
 176free_initmem()
 177{
 178#ifdef CONFIG_RAMKERNEL
 179        unsigned long addr;
 180        extern char __init_begin, __init_end;
 181        /*
 182         * The following code should be cool even if these sections
 183         * are not page aligned.
 184         */
 185        addr = PAGE_ALIGN((unsigned long)(&__init_begin));
 186        /* next to check that the page we free is not a partial page */
 187        for (; addr + PAGE_SIZE < (unsigned long)(&__init_end); addr +=PAGE_SIZE) {
 188                ClearPageReserved(virt_to_page(addr));
 189                init_page_count(virt_to_page(addr));
 190                free_page(addr);
 191                totalram_pages++;
 192        }
 193        printk(KERN_NOTICE "Freeing unused kernel memory: %ldk freed (0x%x - 0x%x)\n",
 194                        (addr - PAGE_ALIGN((long) &__init_begin)) >> 10,
 195                        (int)(PAGE_ALIGN((unsigned long)(&__init_begin))),
 196                        (int)(addr - PAGE_SIZE));
 197#endif
 198}
 199
 200