arch/sh64/mm/init.c

   1 /*
   2  * This file is subject to the terms and conditions of the GNU General Public
   3  * License.  See the file "COPYING" in the main directory of this archive
   4  * for more details.
   5  *
   6  * arch/sh64/mm/init.c
   7  *
   8  * Copyright (C) 2000, 2001  Paolo Alberelli
   9  * Copyright (C) 2003, 2004  Paul Mundt
  10  *
  11  */
  12
  13 #include <linux/init.h>
  14 #include <linux/rwsem.h>
  15 #include <linux/mm.h>
  16 #include <linux/swap.h>
  17 #include <linux/bootmem.h>
  18
  19 #include <asm/mmu_context.h>
  20 #include <asm/page.h>
  21 #include <asm/pgalloc.h>
  22 #include <asm/pgtable.h>
  23 #include <asm/tlb.h>
  24
  25 #ifdef CONFIG_BLK_DEV_INITRD
  26 #include <linux/blk.h>
  27 #endif
  28
  29 DEFINE_PER_CPU(struct mmu_gather, mmu_gathers);
  30
  31 /*
  32  * Cache of MMU context last used.
  33  */
  34 unsigned long mmu_context_cache;
  35 pgd_t * mmu_pdtp_cache;
  36 int after_bootmem = 0;
  37
  38 /*
  39  * BAD_PAGE is the page that is used for page faults when linux
  40  * is out-of-memory. Older versions of linux just did a
  41  * do_exit(), but using this instead means there is less risk
  42  * for a process dying in kernel mode, possibly leaving an inode
  43  * unused etc..
  44  *
  45  * BAD_PAGETABLE is the accompanying page-table: it is initialized
  46  * to point to BAD_PAGE entries.
  47  *
  48  * ZERO_PAGE is a special page that is used for zero-initialized
  49  * data and COW.
  50  */
  51
  52 extern unsigned char empty_zero_page[PAGE_SIZE];
  53 extern unsigned char empty_bad_page[PAGE_SIZE];
  54 extern pte_t empty_bad_pte_table[PTRS_PER_PTE];
  55 extern pgd_t swapper_pg_dir[PTRS_PER_PGD];
  56
  57 extern char _text, _etext, _edata, __bss_start, _end;
  58 extern char __init_begin, __init_end;
  59
  60 /* It'd be good if these lines were in the standard header file. */
  61 #define START_PFN       (NODE_DATA(0)->bdata->node_boot_start >> PAGE_SHIFT)
  62 #define MAX_LOW_PFN     (NODE_DATA(0)->bdata->node_low_pfn)
  63
  64
  65 void show_mem(void)
  66 {
  67         int i, total = 0, reserved = 0;
  68         int shared = 0, cached = 0;
  69
  70         printk("Mem-info:\n");
  71         show_free_areas();
  72         printk("Free swap:       %6ldkB\n",nr_swap_pages<<(PAGE_SHIFT-10));
  73         i = max_mapnr;
  74         while (i-- > 0) {
  75                 total++;
  76                 if (PageReserved(mem_map+i))
  77                         reserved++;
  78                 else if (PageSwapCache(mem_map+i))
  79                         cached++;
  80                 else if (page_count(mem_map+i))
  81                         shared += page_count(mem_map+i) - 1;
  82         }
  83         printk("%d pages of RAM\n",total);
  84         printk("%d reserved pages\n",reserved);
  85         printk("%d pages shared\n",shared);
  86         printk("%d pages swap cached\n",cached);
  87         printk("%ld pages in page table cache\n",pgtable_cache_size);
  88 }
  89
  90 /*
  91  * paging_init() sets up the page tables.
  92  *
  93  * head.S already did a lot to set up address translation for the kernel.
  94  * Here we comes with:
  95  * . MMU enabled
  96  * . ASID set (SR)
  97  * .  some 512MB regions being mapped of which the most relevant here is:
  98  *   . CACHED segment (ASID 0 [irrelevant], shared AND NOT user)
  99  * . possible variable length regions being mapped as:
 100  *   . UNCACHED segment (ASID 0 [irrelevant], shared AND NOT user)
 101  * . All of the memory regions are placed, independently from the platform
 102  *   on high addresses, above 0x80000000.
 103  * . swapper_pg_dir is already cleared out by the .space directive
 104  *   in any case swapper does not require a real page directory since
 105  *   it's all kernel contained.
 106  *
 107  * Those pesky NULL-reference errors in the kernel are then
 108  * dealt with by not mapping address 0x00000000 at all.
 109  *
 110  */
 111 void __init paging_init(void)
 112 {
 113         unsigned long zones_size[MAX_NR_ZONES] = {0, };
 114
 115         pgd_init((unsigned long)swapper_pg_dir);
 116         pgd_init((unsigned long)swapper_pg_dir +
 117                  sizeof(pgd_t) * USER_PTRS_PER_PGD);
 118
 119         mmu_context_cache = MMU_CONTEXT_FIRST_VERSION;
 120
 121         zones_size[ZONE_NORMAL] = MAX_LOW_PFN - START_PFN;
 122         NODE_DATA(0)->node_mem_map = NULL;
 123         free_area_init_node(0, NODE_DATA(0), zones_size, __MEMORY_START >> PAGE_SHIFT, 0);
 124 }
 125
 126 void __init mem_init(void)
 127 {
 128         int codesize, reservedpages, datasize, initsize;
 129         int tmp;
 130
 131         max_mapnr = num_physpages = MAX_LOW_PFN - START_PFN;
 132         high_memory = (void *)__va(MAX_LOW_PFN * PAGE_SIZE);
 133
 134         /*
 135          * Clear the zero-page.
 136          * This is not required but we might want to re-use
 137          * this very page to pass boot parameters, one day.
 138          */
 139         memset(empty_zero_page, 0, PAGE_SIZE);
 140
 141         /* this will put all low memory onto the freelists */
 142         totalram_pages += free_all_bootmem_node(NODE_DATA(0));
 143         reservedpages = 0;
 144         for (tmp = 0; tmp < num_physpages; tmp++)
 145                 /*
 146                  * Only count reserved RAM pages
 147                  */
 148                 if (PageReserved(mem_map+tmp))
 149                         reservedpages++;
 150
 151         after_bootmem = 1;
 152
 153         codesize =  (unsigned long) &_etext - (unsigned long) &_text;
 154         datasize =  (unsigned long) &_edata - (unsigned long) &_etext;
 155         initsize =  (unsigned long) &__init_end - (unsigned long) &__init_begin;
 156
 157         printk("Memory: %luk/%luk available (%dk kernel code, %dk reserved, %dk data, %dk init)\n",
 158                 (unsigned long) nr_free_pages() << (PAGE_SHIFT-10),
 159                 max_mapnr << (PAGE_SHIFT-10),
 160                 codesize >> 10,
 161                 reservedpages << (PAGE_SHIFT-10),
 162                 datasize >> 10,
 163                 initsize >> 10);
 164 }
 165
 166 void free_initmem(void)
 167 {
 168         unsigned long addr;
 169
 170         addr = (unsigned long)(&__init_begin);
 171         for (; addr < (unsigned long)(&__init_end); addr += PAGE_SIZE) {
 172                 ClearPageReserved(virt_to_page(addr));
 173                 init_page_count(virt_to_page(addr));
 174                 free_page(addr);
 175                 totalram_pages++;
 176         }
 177         printk ("Freeing unused kernel memory: %ldk freed\n", (&__init_end - &__init_begin) >> 10);
 178 }
 179
 180 #ifdef CONFIG_BLK_DEV_INITRD
 181 void free_initrd_mem(unsigned long start, unsigned long end)
 182 {
 183         unsigned long p;
 184         for (p = start; p < end; p += PAGE_SIZE) {
 185                 ClearPageReserved(virt_to_page(p));
 186                 init_page_count(virt_to_page(p));
 187                 free_page(p);
 188                 totalram_pages++;
 189         }
 190         printk ("Freeing initrd memory: %ldk freed\n", (end - start) >> 10);
 191 }
 192 #endif
 193