LXR linux/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/mmu_context.h>
  37#include <asm/virtconvert.h>
  38#include <asm/sections.h>
  39#include <asm/tlb.h>
  40
  41#undef DEBUG
  42
  43/*
  44 * BAD_PAGE is the page that is used for page faults when linux
  45 * is out-of-memory. Older versions of linux just did a
  46 * do_exit(), but using this instead means there is less risk
  47 * for a process dying in kernel mode, possibly leaving a inode
  48 * unused etc..
  49 *
  50 * BAD_PAGETABLE is the accompanying page-table: it is initialized
  51 * to point to BAD_PAGE entries.
  52 *
  53 * ZERO_PAGE is a special page that is used for zero-initialized
  54 * data and COW.
  55 */
  56static unsigned long empty_bad_page_table;
  57static unsigned long empty_bad_page;
  58
  59unsigned long empty_zero_page;
  60EXPORT_SYMBOL(empty_zero_page);
  61
  62/*****************************************************************************/
  63/*
  64 * paging_init() continues the virtual memory environment setup which
  65 * was begun by the code in arch/head.S.
  66 * The parameters are pointers to where to stick the starting and ending
  67 * addresses  of available kernel virtual memory.
  68 */
  69void __init paging_init(void)
  70{
  71        unsigned long zones_size[MAX_NR_ZONES] = {0, };
  72
  73        /* allocate some pages for kernel housekeeping tasks */
  74        empty_bad_page_table    = (unsigned long) alloc_bootmem_pages(PAGE_SIZE);
  75        empty_bad_page          = (unsigned long) alloc_bootmem_pages(PAGE_SIZE);
  76        empty_zero_page         = (unsigned long) alloc_bootmem_pages(PAGE_SIZE);
  77
  78        memset((void *) empty_zero_page, 0, PAGE_SIZE);
  79
  80#ifdef CONFIG_HIGHMEM
  81        if (get_num_physpages() - num_mappedpages) {
  82                pgd_t *pge;
  83                pud_t *pue;
  84                pmd_t *pme;
  85
  86                pkmap_page_table = alloc_bootmem_pages(PAGE_SIZE);
  87
  88                pge = swapper_pg_dir + pgd_index_k(PKMAP_BASE);
  89                pue = pud_offset(pge, PKMAP_BASE);
  90                pme = pmd_offset(pue, PKMAP_BASE);
  91                __set_pmd(pme, virt_to_phys(pkmap_page_table) | _PAGE_TABLE);
  92        }
  93#endif
  94
  95        /* distribute the allocatable pages across the various zones and pass them to the allocator
  96         */
  97        zones_size[ZONE_NORMAL]  = max_low_pfn - min_low_pfn;
  98#ifdef CONFIG_HIGHMEM
  99        zones_size[ZONE_HIGHMEM] = get_num_physpages() - num_mappedpages;
 100#endif
 101
 102        free_area_init(zones_size);
 103
 104#ifdef CONFIG_MMU
 105        /* initialise init's MMU context */
 106        init_new_context(&init_task, &init_mm);
 107#endif
 108
 109} /* end paging_init() */
 110
 111/*****************************************************************************/
 112/*
 113 *
 114 */
 115void __init mem_init(void)
 116{
 117        unsigned long code_size = _etext - _stext;
 118
 119        /* this will put all low memory onto the freelists */
 120        free_all_bootmem();
 121#if defined(CONFIG_MMU) && defined(CONFIG_HIGHMEM)
 122        {
 123                unsigned long pfn;
 124
 125                for (pfn = get_num_physpages() - 1;
 126                     pfn >= num_mappedpages; pfn--)
 127                        free_highmem_page(&mem_map[pfn]);
 128        }
 129#endif
 130
 131        mem_init_print_info(NULL);
 132        if (rom_length > 0 && rom_length >= code_size)
 133                printk("Memory available:  %luKiB/%luKiB ROM\n",
 134                        (rom_length - code_size) >> 10, rom_length >> 10);
 135} /* end mem_init() */
 136
 137/*****************************************************************************/
 138/*
 139 * free the memory that was only required for initialisation
 140 */
 141void free_initmem(void)
 142{
 143#if defined(CONFIG_RAMKERNEL) && !defined(CONFIG_PROTECT_KERNEL)
 144        free_initmem_default(-1);
 145#endif
 146} /* end free_initmem() */
 147
 148/*****************************************************************************/
 149/*
 150 * free the initial ramdisk memory
 151 */
 152#ifdef CONFIG_BLK_DEV_INITRD
 153void __init free_initrd_mem(unsigned long start, unsigned long end)
 154{
 155        free_reserved_area((void *)start, (void *)end, -1, "initrd");
 156} /* end free_initrd_mem() */
 157#endif
 158