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/swap.h>
  23 #include <linux/mm.h>
  24 #include <linux/kernel.h>
  25 #include <linux/string.h>
  26 #include <linux/types.h>
  27 #include <linux/bootmem.h>
  28 #include <linux/highmem.h>
  29 #include <linux/module.h>
  30
  31 #include <asm/setup.h>
  32 #include <asm/segment.h>
  33 #include <asm/page.h>
  34 #include <asm/pgtable.h>
  35 #include <asm/system.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 DEFINE_PER_CPU(struct mmu_gather, mmu_gathers);
  44
  45 /*
  46  * BAD_PAGE is the page that is used for page faults when linux
  47  * is out-of-memory. Older versions of linux just did a
  48  * do_exit(), but using this instead means there is less risk
  49  * for a process dying in kernel mode, possibly leaving a inode
  50  * unused etc..
  51  *
  52  * BAD_PAGETABLE is the accompanying page-table: it is initialized
  53  * to point to BAD_PAGE entries.
  54  *
  55  * ZERO_PAGE is a special page that is used for zero-initialized
  56  * data and COW.
  57  */
  58 static unsigned long empty_bad_page_table;
  59 static unsigned long empty_bad_page;
  60
  61 unsigned long empty_zero_page;
  62 EXPORT_SYMBOL(empty_zero_page);
  63
  64 /*****************************************************************************/
  65 /*
  66  * paging_init() continues the virtual memory environment setup which
  67  * was begun by the code in arch/head.S.
  68  * The parameters are pointers to where to stick the starting and ending
  69  * addresses  of available kernel virtual memory.
  70  */
  71 void __init paging_init(void)
  72 {
  73         unsigned long zones_size[MAX_NR_ZONES] = {0, };
  74
  75         /* allocate some pages for kernel housekeeping tasks */
  76         empty_bad_page_table    = (unsigned long) alloc_bootmem_pages(PAGE_SIZE);
  77         empty_bad_page          = (unsigned long) alloc_bootmem_pages(PAGE_SIZE);
  78         empty_zero_page         = (unsigned long) alloc_bootmem_pages(PAGE_SIZE);
  79
  80         memset((void *) empty_zero_page, 0, PAGE_SIZE);
  81
  82 #ifdef CONFIG_HIGHMEM
  83         if (num_physpages - num_mappedpages) {
  84                 pgd_t *pge;
  85                 pud_t *pue;
  86                 pmd_t *pme;
  87
  88                 pkmap_page_table = alloc_bootmem_pages(PAGE_SIZE);
  89
  90                 memset(pkmap_page_table, 0, PAGE_SIZE);
  91
  92                 pge = swapper_pg_dir + pgd_index_k(PKMAP_BASE);
  93                 pue = pud_offset(pge, PKMAP_BASE);
  94                 pme = pmd_offset(pue, PKMAP_BASE);
  95                 __set_pmd(pme, virt_to_phys(pkmap_page_table) | _PAGE_TABLE);
  96         }
  97 #endif
  98
  99         /* distribute the allocatable pages across the various zones and pass them to the allocator
 100          */
 101         zones_size[ZONE_NORMAL]  = max_low_pfn - min_low_pfn;
 102 #ifdef CONFIG_HIGHMEM
 103         zones_size[ZONE_HIGHMEM] = num_physpages - num_mappedpages;
 104 #endif
 105
 106         free_area_init(zones_size);
 107
 108 #ifdef CONFIG_MMU
 109         /* initialise init's MMU context */
 110         init_new_context(&init_task, &init_mm);
 111 #endif
 112
 113 } /* end paging_init() */
 114
 115 /*****************************************************************************/
 116 /*
 117  *
 118  */
 119 void __init mem_init(void)
 120 {
 121         unsigned long npages = (memory_end - memory_start) >> PAGE_SHIFT;
 122         unsigned long tmp;
 123 #ifdef CONFIG_MMU
 124         unsigned long loop, pfn;
 125         int datapages = 0;
 126 #endif
 127         int codek = 0, datak = 0;
 128
 129         /* this will put all memory onto the freelists */
 130         totalram_pages = free_all_bootmem();
 131
 132 #ifdef CONFIG_MMU
 133         for (loop = 0 ; loop < npages ; loop++)
 134                 if (PageReserved(&mem_map[loop]))
 135                         datapages++;
 136
 137 #ifdef CONFIG_HIGHMEM
 138         for (pfn = num_physpages - 1; pfn >= num_mappedpages; pfn--) {
 139                 struct page *page = &mem_map[pfn];
 140
 141                 ClearPageReserved(page);
 142                 init_page_count(page);
 143                 __free_page(page);
 144                 totalram_pages++;
 145         }
 146 #endif
 147
 148         codek = ((unsigned long) &_etext - (unsigned long) &_stext) >> 10;
 149         datak = datapages << (PAGE_SHIFT - 10);
 150
 151 #else
 152         codek = (_etext - _stext) >> 10;
 153         datak = 0; //(_ebss - _sdata) >> 10;
 154 #endif
 155
 156         tmp = nr_free_pages() << PAGE_SHIFT;
 157         printk("Memory available: %luKiB/%luKiB RAM, %luKiB/%luKiB ROM (%dKiB kernel code, %dKiB data)\n",
 158                tmp >> 10,
 159                npages << (PAGE_SHIFT - 10),
 160                (rom_length > 0) ? ((rom_length >> 10) - codek) : 0,
 161                rom_length >> 10,
 162                codek,
 163                datak
 164                );
 165
 166 } /* end mem_init() */
 167
 168 /*****************************************************************************/
 169 /*
 170  * free the memory that was only required for initialisation
 171  */
 172 void free_initmem(void)
 173 {
 174 #if defined(CONFIG_RAMKERNEL) && !defined(CONFIG_PROTECT_KERNEL)
 175         unsigned long start, end, addr;
 176
 177         start = PAGE_ALIGN((unsigned long) &__init_begin);      /* round up */
 178         end   = ((unsigned long) &__init_end) & PAGE_MASK;      /* round down */
 179
 180         /* next to check that the page we free is not a partial page */
 181         for (addr = start; addr < 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
 188         printk("Freeing unused kernel memory: %ldKiB freed (0x%lx - 0x%lx)\n",
 189                (end - start) >> 10, start, end);
 190 #endif
 191 } /* end free_initmem() */
 192
 193 /*****************************************************************************/
 194 /*
 195  * free the initial ramdisk memory
 196  */
 197 #ifdef CONFIG_BLK_DEV_INITRD
 198 void __init free_initrd_mem(unsigned long start, unsigned long end)
 199 {
 200         int pages = 0;
 201         for (; start < end; start += PAGE_SIZE) {
 202                 ClearPageReserved(virt_to_page(start));
 203                 init_page_count(virt_to_page(start));
 204                 free_page(start);
 205                 totalram_pages++;
 206                 pages++;
 207         }
 208         printk("Freeing initrd memory: %dKiB freed\n", (pages * PAGE_SIZE) >> 10);
 209 } /* end free_initrd_mem() */
 210 #endif