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  */
  56 static unsigned long empty_bad_page_table;
  57 static unsigned long empty_bad_page;
  58
  59 unsigned long empty_zero_page;
  60 EXPORT_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  */
  69 void __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  */
 115 void __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  */
 141 void 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
 153 void __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