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 (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] = 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 npages = (memory_end - memory_start) >> PAGE_SHIFT;
 118         unsigned long tmp;
 119 #ifdef CONFIG_MMU
 120         unsigned long loop, pfn;
 121         int datapages = 0;
 122 #endif
 123         int codek = 0, datak = 0;
 124
 125         /* this will put all memory onto the freelists */
 126         totalram_pages = free_all_bootmem();
 127
 128 #ifdef CONFIG_MMU
 129         for (loop = 0 ; loop < npages ; loop++)
 130                 if (PageReserved(&mem_map[loop]))
 131                         datapages++;
 132
 133 #ifdef CONFIG_HIGHMEM
 134         for (pfn = num_physpages - 1; pfn >= num_mappedpages; pfn--) {
 135                 struct page *page = &mem_map[pfn];
 136
 137                 ClearPageReserved(page);
 138                 init_page_count(page);
 139                 __free_page(page);
 140                 totalram_pages++;
 141         }
 142 #endif
 143
 144         codek = ((unsigned long) &_etext - (unsigned long) &_stext) >> 10;
 145         datak = datapages << (PAGE_SHIFT - 10);
 146
 147 #else
 148         codek = (_etext - _stext) >> 10;
 149         datak = 0; //(__bss_stop - _sdata) >> 10;
 150 #endif
 151
 152         tmp = nr_free_pages() << PAGE_SHIFT;
 153         printk("Memory available: %luKiB/%luKiB RAM, %luKiB/%luKiB ROM (%dKiB kernel code, %dKiB data)\n",
 154                tmp >> 10,
 155                npages << (PAGE_SHIFT - 10),
 156                (rom_length > 0) ? ((rom_length >> 10) - codek) : 0,
 157                rom_length >> 10,
 158                codek,
 159                datak
 160                );
 161
 162 } /* end mem_init() */
 163
 164 /*****************************************************************************/
 165 /*
 166  * free the memory that was only required for initialisation
 167  */
 168 void free_initmem(void)
 169 {
 170 #if defined(CONFIG_RAMKERNEL) && !defined(CONFIG_PROTECT_KERNEL)
 171         unsigned long start, end, addr;
 172
 173         start = PAGE_ALIGN((unsigned long) &__init_begin);      /* round up */
 174         end   = ((unsigned long) &__init_end) & PAGE_MASK;      /* round down */
 175
 176         /* next to check that the page we free is not a partial page */
 177         for (addr = start; addr < end; addr += PAGE_SIZE) {
 178                 ClearPageReserved(virt_to_page(addr));
 179                 init_page_count(virt_to_page(addr));
 180                 free_page(addr);
 181                 totalram_pages++;
 182         }
 183
 184         printk("Freeing unused kernel memory: %ldKiB freed (0x%lx - 0x%lx)\n",
 185                (end - start) >> 10, start, end);
 186 #endif
 187 } /* end free_initmem() */
 188
 189 /*****************************************************************************/
 190 /*
 191  * free the initial ramdisk memory
 192  */
 193 #ifdef CONFIG_BLK_DEV_INITRD
 194 void __init free_initrd_mem(unsigned long start, unsigned long end)
 195 {
 196         int pages = 0;
 197         for (; start < end; start += PAGE_SIZE) {
 198                 ClearPageReserved(virt_to_page(start));
 199                 init_page_count(virt_to_page(start));
 200                 free_page(start);
 201                 totalram_pages++;
 202                 pages++;
 203         }
 204         printk("Freeing initrd memory: %dKiB freed\n", (pages * PAGE_SIZE) >> 10);
 205 } /* end free_initrd_mem() */
 206 #endif