arch/m68knommu/mm/init.c

   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
  43 extern void die_if_kernel(char *,struct pt_regs *,long);
  44 extern 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  */
  59 static unsigned long empty_bad_page_table;
  60
  61 static unsigned long empty_bad_page;
  62
  63 unsigned long empty_zero_page;
  64
  65 extern unsigned long memory_start;
  66 extern 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  */
  74 void __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] = (end_mem - PAGE_OFFSET) >> PAGE_SHIFT;
 115                 free_area_init(zones_size);
 116         }
 117 }
 118
 119 void __init mem_init(void)
 120 {
 121         int codek = 0, datak = 0, initk = 0;
 122         unsigned long tmp;
 123         extern char _etext, _stext, _sdata, _ebss, __init_begin, __init_end;
 124         extern unsigned int _ramend, _rambase;
 125         unsigned long len = _ramend - _rambase;
 126         unsigned long start_mem = memory_start; /* DAVIDM - these must start at end of kernel */
 127         unsigned long end_mem   = memory_end; /* DAVIDM - this must not include kernel stack at top */
 128
 129         pr_debug("Mem_init: start=%lx, end=%lx\n", start_mem, end_mem);
 130
 131         end_mem &= PAGE_MASK;
 132         high_memory = (void *) end_mem;
 133
 134         start_mem = PAGE_ALIGN(start_mem);
 135         max_mapnr = num_physpages = (((unsigned long) high_memory) - PAGE_OFFSET) >> PAGE_SHIFT;
 136
 137         /* this will put all memory onto the freelists */
 138         totalram_pages = free_all_bootmem();
 139
 140         codek = (&_etext - &_stext) >> 10;
 141         datak = (&_ebss - &_sdata) >> 10;
 142         initk = (&__init_begin - &__init_end) >> 10;
 143
 144         tmp = nr_free_pages() << PAGE_SHIFT;
 145         printk(KERN_INFO "Memory available: %luk/%luk RAM, (%dk kernel code, %dk data)\n",
 146                tmp >> 10,
 147                len >> 10,
 148                codek,
 149                datak
 150                );
 151 }
 152
 153
 154 #ifdef CONFIG_BLK_DEV_INITRD
 155 void free_initrd_mem(unsigned long start, unsigned long end)
 156 {
 157         int pages = 0;
 158         for (; start < end; start += PAGE_SIZE) {
 159                 ClearPageReserved(virt_to_page(start));
 160                 init_page_count(virt_to_page(start));
 161                 free_page(start);
 162                 totalram_pages++;
 163                 pages++;
 164         }
 165         printk (KERN_NOTICE "Freeing initrd memory: %dk freed\n", pages * (PAGE_SIZE / 1024));
 166 }
 167 #endif
 168
 169 void
 170 free_initmem()
 171 {
 172 #ifdef CONFIG_RAMKERNEL
 173         unsigned long addr;
 174         extern char __init_begin, __init_end;
 175         /*
 176          * The following code should be cool even if these sections
 177          * are not page aligned.
 178          */
 179         addr = PAGE_ALIGN((unsigned long)(&__init_begin));
 180         /* next to check that the page we free is not a partial page */
 181         for (; addr + PAGE_SIZE < (unsigned long)(&__init_end); addr +=PAGE_SIZE) {
 182                 ClearPageReserved(virt_to_page(addr));
 183                 init_page_count(virt_to_page(addr));
 184                 free_page(addr);
 185                 totalram_pages++;
 186         }
 187         printk(KERN_NOTICE "Freeing unused kernel memory: %ldk freed (0x%x - 0x%x)\n",
 188                         (addr - PAGE_ALIGN((long) &__init_begin)) >> 10,
 189                         (int)(PAGE_ALIGN((unsigned long)(&__init_begin))),
 190                         (int)(addr - PAGE_SIZE));
 191 #endif
 192 }
 193