release/src-rt-6.x.4708/linux/linux-2.6.36/arch/frv/mm/init.c

   1 /* init.c: memory initialisation for FRV
   2  *
   3  * Copyright (C) 2004 Red Hat, Inc. All Rights Reserved.
   4  * Written by David Howells (dhowells@redhat.com)
   5  *
   6  * This program is free software; you can redistribute it and/or
   7  * modify it under the terms of the GNU General Public License
   8  * as published by the Free Software Foundation; either version
   9  * 2 of the License, or (at your option) any later version.
  10  *
  11  * Derived from:
  12  *  - linux/arch/m68knommu/mm/init.c
  13  *    - Copyright (C) 1998  D. Jeff Dionne <jeff@lineo.ca>, Kenneth Albanowski <kjahds@kjahds.com>,
  14  *    - Copyright (C) 2000  Lineo, Inc.  (www.lineo.com)
  15  *  - linux/arch/m68k/mm/init.c
  16  *    - Copyright (C) 1995  Hamish Macdonald
  17  */
  18
  19 #include <linux/signal.h>
  20 #include <linux/sched.h>
  21 #include <linux/pagemap.h>
  22 #include <linux/gfp.h>
  23 #include <linux/swap.h>
  24 #include <linux/mm.h>
  25 #include <linux/kernel.h>
  26 #include <linux/string.h>
  27 #include <linux/types.h>
  28 #include <linux/bootmem.h>
  29 #include <linux/highmem.h>
  30 #include <linux/module.h>
  31
  32 #include <asm/setup.h>
  33 #include <asm/segment.h>
  34 #include <asm/page.h>
  35 #include <asm/pgtable.h>
  36 #include <asm/system.h>
  37 #include <asm/mmu_context.h>
  38 #include <asm/virtconvert.h>
  39 #include <asm/sections.h>
  40 #include <asm/tlb.h>
  41
  42 #undef DEBUG
  43
  44 DEFINE_PER_CPU(struct mmu_gather, mmu_gathers);
  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 static unsigned long empty_bad_page;
  61
  62 unsigned long empty_zero_page;
  63 EXPORT_SYMBOL(empty_zero_page);
  64
  65 /*****************************************************************************/
  66 /*
  67  * paging_init() continues the virtual memory environment setup which
  68  * was begun by the code in arch/head.S.
  69  * The parameters are pointers to where to stick the starting and ending
  70  * addresses  of available kernel virtual memory.
  71  */
  72 void __init paging_init(void)
  73 {
  74         unsigned long zones_size[MAX_NR_ZONES] = {0, };
  75
  76         /* allocate some pages for kernel housekeeping tasks */
  77         empty_bad_page_table    = (unsigned long) alloc_bootmem_pages(PAGE_SIZE);
  78         empty_bad_page          = (unsigned long) alloc_bootmem_pages(PAGE_SIZE);
  79         empty_zero_page         = (unsigned long) alloc_bootmem_pages(PAGE_SIZE);
  80
  81         memset((void *) empty_zero_page, 0, PAGE_SIZE);
  82
  83 #ifdef CONFIG_HIGHMEM
  84         if (num_physpages - num_mappedpages) {
  85                 pgd_t *pge;
  86                 pud_t *pue;
  87                 pmd_t *pme;
  88
  89                 pkmap_page_table = alloc_bootmem_pages(PAGE_SIZE);
  90
  91                 pge = swapper_pg_dir + pgd_index_k(PKMAP_BASE);
  92                 pue = pud_offset(pge, PKMAP_BASE);
  93                 pme = pmd_offset(pue, PKMAP_BASE);
  94                 __set_pmd(pme, virt_to_phys(pkmap_page_table) | _PAGE_TABLE);
  95         }
  96 #endif
  97
  98         /* distribute the allocatable pages across the various zones and pass them to the allocator
  99          */
 100         zones_size[ZONE_NORMAL]  = max_low_pfn - min_low_pfn;
 101 #ifdef CONFIG_HIGHMEM
 102         zones_size[ZONE_HIGHMEM] = num_physpages - num_mappedpages;
 103 #endif
 104
 105         free_area_init(zones_size);
 106
 107 #ifdef CONFIG_MMU
 108         /* initialise init's MMU context */
 109         init_new_context(&init_task, &init_mm);
 110 #endif
 111
 112 } /* end paging_init() */
 113
 114 /*****************************************************************************/
 115 /*
 116  *
 117  */
 118 void __init mem_init(void)
 119 {
 120         unsigned long npages = (memory_end - memory_start) >> PAGE_SHIFT;
 121         unsigned long tmp;
 122 #ifdef CONFIG_MMU
 123         unsigned long loop, pfn;
 124         int datapages = 0;
 125 #endif
 126         int codek = 0, datak = 0;
 127
 128         /* this will put all memory onto the freelists */
 129         totalram_pages = free_all_bootmem();
 130
 131 #ifdef CONFIG_MMU
 132         for (loop = 0 ; loop < npages ; loop++)
 133                 if (PageReserved(&mem_map[loop]))
 134                         datapages++;
 135
 136 #ifdef CONFIG_HIGHMEM
 137         for (pfn = num_physpages - 1; pfn >= num_mappedpages; pfn--) {
 138                 struct page *page = &mem_map[pfn];
 139
 140                 ClearPageReserved(page);
 141                 init_page_count(page);
 142                 __free_page(page);
 143                 totalram_pages++;
 144         }
 145 #endif
 146
 147         codek = ((unsigned long) &_etext - (unsigned long) &_stext) >> 10;
 148         datak = datapages << (PAGE_SHIFT - 10);
 149
 150 #else
 151         codek = (_etext - _stext) >> 10;
 152         datak = 0; //(_ebss - _sdata) >> 10;
 153 #endif
 154
 155         tmp = nr_free_pages() << PAGE_SHIFT;
 156         printk("Memory available: %luKiB/%luKiB RAM, %luKiB/%luKiB ROM (%dKiB kernel code, %dKiB data)\n",
 157                tmp >> 10,
 158                npages << (PAGE_SHIFT - 10),
 159                (rom_length > 0) ? ((rom_length >> 10) - codek) : 0,
 160                rom_length >> 10,
 161                codek,
 162                datak
 163                );
 164
 165 } /* end mem_init() */
 166
 167 /*****************************************************************************/
 168 /*
 169  * free the memory that was only required for initialisation
 170  */
 171 void free_initmem(void)
 172 {
 173 #if defined(CONFIG_RAMKERNEL) && !defined(CONFIG_PROTECT_KERNEL)
 174         unsigned long start, end, addr;
 175
 176         start = PAGE_ALIGN((unsigned long) &__init_begin);      /* round up */
 177         end   = ((unsigned long) &__init_end) & PAGE_MASK;      /* round down */
 178
 179         /* next to check that the page we free is not a partial page */
 180         for (addr = start; addr < end; addr += PAGE_SIZE) {
 181                 ClearPageReserved(virt_to_page(addr));
 182                 init_page_count(virt_to_page(addr));
 183                 free_page(addr);
 184                 totalram_pages++;
 185         }
 186
 187         printk("Freeing unused kernel memory: %ldKiB freed (0x%lx - 0x%lx)\n",
 188                (end - start) >> 10, start, end);
 189 #endif
 190 } /* end free_initmem() */
 191
 192 /*****************************************************************************/
 193 /*
 194  * free the initial ramdisk memory
 195  */
 196 #ifdef CONFIG_BLK_DEV_INITRD
 197 void __init free_initrd_mem(unsigned long start, unsigned long end)
 198 {
 199         int pages = 0;
 200         for (; start < end; start += PAGE_SIZE) {
 201                 ClearPageReserved(virt_to_page(start));
 202                 init_page_count(virt_to_page(start));
 203                 free_page(start);
 204                 totalram_pages++;
 205                 pages++;
 206         }
 207         printk("Freeing initrd memory: %dKiB freed\n", (pages * PAGE_SIZE) >> 10);
 208 } /* end free_initrd_mem() */
 209 #endif