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/sched/task.h>
  22#include <linux/pagemap.h>
  23#include <linux/gfp.h>
  24#include <linux/swap.h>
  25#include <linux/mm.h>
  26#include <linux/kernel.h>
  27#include <linux/string.h>
  28#include <linux/types.h>
  29#include <linux/bootmem.h>
  30#include <linux/highmem.h>
  31#include <linux/module.h>
  32
  33#include <asm/setup.h>
  34#include <asm/segment.h>
  35#include <asm/page.h>
  36#include <asm/pgtable.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/*
  45 * BAD_PAGE is the page that is used for page faults when linux
  46 * is out-of-memory. Older versions of linux just did a
  47 * do_exit(), but using this instead means there is less risk
  48 * for a process dying in kernel mode, possibly leaving a inode
  49 * unused etc..
  50 *
  51 * BAD_PAGETABLE is the accompanying page-table: it is initialized
  52 * to point to BAD_PAGE entries.
  53 *
  54 * ZERO_PAGE is a special page that is used for zero-initialized
  55 * data and COW.
  56 */
  57static unsigned long empty_bad_page_table;
  58static unsigned long empty_bad_page;
  59
  60unsigned long empty_zero_page;
  61EXPORT_SYMBOL(empty_zero_page);
  62
  63/*****************************************************************************/
  64/*
  65 * paging_init() continues the virtual memory environment setup which
  66 * was begun by the code in arch/head.S.
  67 * The parameters are pointers to where to stick the starting and ending
  68 * addresses  of available kernel virtual memory.
  69 */
  70void __init paging_init(void)
  71{
  72        unsigned long zones_size[MAX_NR_ZONES] = {0, };
  73
  74        /* allocate some pages for kernel housekeeping tasks */
  75        empty_bad_page_table    = (unsigned long) alloc_bootmem_pages(PAGE_SIZE);
  76        empty_bad_page          = (unsigned long) alloc_bootmem_pages(PAGE_SIZE);
  77        empty_zero_page         = (unsigned long) alloc_bootmem_pages(PAGE_SIZE);
  78
  79        memset((void *) empty_zero_page, 0, PAGE_SIZE);
  80
  81#ifdef CONFIG_HIGHMEM
  82        if (get_num_physpages() - num_mappedpages) {
  83                pgd_t *pge;
  84                pud_t *pue;
  85                pmd_t *pme;
  86
  87                pkmap_page_table = alloc_bootmem_pages(PAGE_SIZE);
  88
  89                pge = swapper_pg_dir + pgd_index_k(PKMAP_BASE);
  90                pue = pud_offset(pge, PKMAP_BASE);
  91                pme = pmd_offset(pue, PKMAP_BASE);
  92                __set_pmd(pme, virt_to_phys(pkmap_page_table) | _PAGE_TABLE);
  93        }
  94#endif
  95
  96        /* distribute the allocatable pages across the various zones and pass them to the allocator
  97         */
  98        zones_size[ZONE_NORMAL]  = max_low_pfn - min_low_pfn;
  99#ifdef CONFIG_HIGHMEM
 100        zones_size[ZONE_HIGHMEM] = get_num_physpages() - num_mappedpages;
 101#endif
 102
 103        free_area_init(zones_size);
 104
 105#ifdef CONFIG_MMU
 106        /* initialise init's MMU context */
 107        init_new_context(&init_task, &init_mm);
 108#endif
 109
 110} /* end paging_init() */
 111
 112/*****************************************************************************/
 113/*
 114 *
 115 */
 116void __init mem_init(void)
 117{
 118        unsigned long code_size = _etext - _stext;
 119
 120        /* this will put all low memory onto the freelists */
 121        free_all_bootmem();
 122#if defined(CONFIG_MMU) && defined(CONFIG_HIGHMEM)
 123        {
 124                unsigned long pfn;
 125
 126                for (pfn = get_num_physpages() - 1;
 127                     pfn >= num_mappedpages; pfn--)
 128                        free_highmem_page(&mem_map[pfn]);
 129        }
 130#endif
 131
 132        mem_init_print_info(NULL);
 133        if (rom_length > 0 && rom_length >= code_size)
 134                printk("Memory available:  %luKiB/%luKiB ROM\n",
 135                        (rom_length - code_size) >> 10, rom_length >> 10);
 136} /* end mem_init() */
 137
 138/*****************************************************************************/
 139/*
 140 * free the memory that was only required for initialisation
 141 */
 142void free_initmem(void)
 143{
 144#if defined(CONFIG_RAMKERNEL) && !defined(CONFIG_PROTECT_KERNEL)
 145        free_initmem_default(-1);
 146#endif
 147} /* end free_initmem() */
 148
 149/*****************************************************************************/
 150/*
 151 * free the initial ramdisk memory
 152 */
 153#ifdef CONFIG_BLK_DEV_INITRD
 154void __init free_initrd_mem(unsigned long start, unsigned long end)
 155{
 156        free_reserved_area((void *)start, (void *)end, -1, "initrd");
 157} /* end free_initrd_mem() */
 158#endif
 159