arch/sh/mm/init.c

   1 /* $Id: init.c,v 1.19 2004/02/21 04:42:16 kkojima Exp $
   2  *
   3  *  linux/arch/sh/mm/init.c
   4  *
   5  *  Copyright (C) 1999  Niibe Yutaka
   6  *  Copyright (C) 2002, 2004  Paul Mundt
   7  *
   8  *  Based on linux/arch/i386/mm/init.c:
   9  *   Copyright (C) 1995  Linus Torvalds
  10  */
  11
  12 #include <linux/signal.h>
  13 #include <linux/sched.h>
  14 #include <linux/kernel.h>
  15 #include <linux/errno.h>
  16 #include <linux/string.h>
  17 #include <linux/types.h>
  18 #include <linux/ptrace.h>
  19 #include <linux/mman.h>
  20 #include <linux/mm.h>
  21 #include <linux/swap.h>
  22 #include <linux/smp.h>
  23 #include <linux/init.h>
  24 #include <linux/highmem.h>
  25 #include <linux/bootmem.h>
  26 #include <linux/pagemap.h>
  27
  28 #include <asm/processor.h>
  29 #include <asm/system.h>
  30 #include <asm/uaccess.h>
  31 #include <asm/pgtable.h>
  32 #include <asm/pgalloc.h>
  33 #include <asm/mmu_context.h>
  34 #include <asm/io.h>
  35 #include <asm/tlb.h>
  36 #include <asm/cacheflush.h>
  37 #include <asm/cache.h>
  38
  39 DEFINE_PER_CPU(struct mmu_gather, mmu_gathers);
  40 pgd_t swapper_pg_dir[PTRS_PER_PGD];
  41
  42 /*
  43  * Cache of MMU context last used.
  44  */
  45 unsigned long mmu_context_cache = NO_CONTEXT;
  46
  47 #ifdef CONFIG_MMU
  48 /* It'd be good if these lines were in the standard header file. */
  49 #define START_PFN       (NODE_DATA(0)->bdata->node_boot_start >> PAGE_SHIFT)
  50 #define MAX_LOW_PFN     (NODE_DATA(0)->bdata->node_low_pfn)
  51 #endif
  52
  53 void (*copy_page)(void *from, void *to);
  54 void (*clear_page)(void *to);
  55
  56 void show_mem(void)
  57 {
  58         int i, total = 0, reserved = 0;
  59         int shared = 0, cached = 0;
  60
  61         printk("Mem-info:\n");
  62         show_free_areas();
  63         printk("Free swap:       %6ldkB\n", nr_swap_pages<<(PAGE_SHIFT-10));
  64         i = max_mapnr;
  65         while (i-- > 0) {
  66                 total++;
  67                 if (PageReserved(mem_map+i))
  68                         reserved++;
  69                 else if (PageSwapCache(mem_map+i))
  70                         cached++;
  71                 else if (page_count(mem_map+i))
  72                         shared += page_count(mem_map+i) - 1;
  73         }
  74         printk("%d pages of RAM\n",total);
  75         printk("%d reserved pages\n",reserved);
  76         printk("%d pages shared\n",shared);
  77         printk("%d pages swap cached\n",cached);
  78 }
  79
  80 static void set_pte_phys(unsigned long addr, unsigned long phys, pgprot_t prot)
  81 {
  82         pgd_t *pgd;
  83         pmd_t *pmd;
  84         pte_t *pte;
  85
  86         pgd = swapper_pg_dir + pgd_index(addr);
  87         if (pgd_none(*pgd)) {
  88                 pgd_ERROR(*pgd);
  89                 return;
  90         }
  91
  92         pmd = pmd_offset(pgd, addr);
  93         if (pmd_none(*pmd)) {
  94                 pte = (pte_t *)get_zeroed_page(GFP_ATOMIC);
  95                 set_pmd(pmd, __pmd(__pa(pte) | _KERNPG_TABLE | _PAGE_USER));
  96                 if (pte != pte_offset_kernel(pmd, 0)) {
  97                         pmd_ERROR(*pmd);
  98                         return;
  99                 }
 100         }
 101
 102         pte = pte_offset_kernel(pmd, addr);
 103         if (!pte_none(*pte)) {
 104                 pte_ERROR(*pte);
 105                 return;
 106         }
 107
 108         set_pte(pte, pfn_pte(phys >> PAGE_SHIFT, prot));
 109
 110         __flush_tlb_page(get_asid(), addr);
 111 }
 112
 113 /*
 114  * As a performance optimization, other platforms preserve the fixmap mapping
 115  * across a context switch, we don't presently do this, but this could be done
 116  * in a similar fashion as to the wired TLB interface that sh64 uses (by way
 117  * of the memorry mapped UTLB configuration) -- this unfortunately forces us to
 118  * give up a TLB entry for each mapping we want to preserve. While this may be
 119  * viable for a small number of fixmaps, it's not particularly useful for
 120  * everything and needs to be carefully evaluated. (ie, we may want this for
 121  * the vsyscall page).
 122  *
 123  * XXX: Perhaps add a _PAGE_WIRED flag or something similar that we can pass
 124  * in at __set_fixmap() time to determine the appropriate behavior to follow.
 125  *
 126  *                                       -- PFM.
 127  */
 128 void __set_fixmap(enum fixed_addresses idx, unsigned long phys, pgprot_t prot)
 129 {
 130         unsigned long address = __fix_to_virt(idx);
 131
 132         if (idx >= __end_of_fixed_addresses) {
 133                 BUG();
 134                 return;
 135         }
 136
 137         set_pte_phys(address, phys, prot);
 138 }
 139
 140 /* References to section boundaries */
 141
 142 extern char _text, _etext, _edata, __bss_start, _end;
 143 extern char __init_begin, __init_end;
 144
 145 /*
 146  * paging_init() sets up the page tables
 147  *
 148  * This routines also unmaps the page at virtual kernel address 0, so
 149  * that we can trap those pesky NULL-reference errors in the kernel.
 150  */
 151 void __init paging_init(void)
 152 {
 153         unsigned long zones_size[MAX_NR_ZONES] = { 0, };
 154
 155         /*
 156          * Setup some defaults for the zone sizes.. these should be safe
 157          * regardless of distcontiguous memory or MMU settings.
 158          */
 159         zones_size[ZONE_DMA] = 0 >> PAGE_SHIFT;
 160         zones_size[ZONE_NORMAL] = __MEMORY_SIZE >> PAGE_SHIFT;
 161 #ifdef CONFIG_HIGHMEM
 162         zones_size[ZONE_HIGHMEM] = 0 >> PAGE_SHIFT;
 163 #endif
 164
 165 #ifdef CONFIG_MMU
 166         /*
 167          * If we have an MMU, and want to be using it .. we need to adjust
 168          * the zone sizes accordingly, in addition to turning it on.
 169          */
 170         {
 171                 unsigned long max_dma, low, start_pfn;
 172                 pgd_t *pg_dir;
 173                 int i;
 174
 175                 /* We don't need kernel mapping as hardware support that. */
 176                 pg_dir = swapper_pg_dir;
 177
 178                 for (i = 0; i < PTRS_PER_PGD; i++)
 179                         pgd_val(pg_dir[i]) = 0;
 180
 181                 /* Turn on the MMU */
 182                 enable_mmu();
 183
 184                 /* Fixup the zone sizes */
 185                 start_pfn = START_PFN;
 186                 max_dma = virt_to_phys((char *)MAX_DMA_ADDRESS) >> PAGE_SHIFT;
 187                 low = MAX_LOW_PFN;
 188
 189                 if (low < max_dma) {
 190                         zones_size[ZONE_DMA] = low - start_pfn;
 191                         zones_size[ZONE_NORMAL] = 0;
 192                 } else {
 193                         zones_size[ZONE_DMA] = max_dma - start_pfn;
 194                         zones_size[ZONE_NORMAL] = low - max_dma;
 195                 }
 196         }
 197
 198 #elif defined(CONFIG_CPU_SH3) || defined(CONFIG_CPU_SH4)
 199         /*
 200          * If we don't have CONFIG_MMU set and the processor in question
 201          * still has an MMU, care needs to be taken to make sure it doesn't
 202          * stay on.. Since the boot loader could have potentially already
 203          * turned it on, and we clearly don't want it, we simply turn it off.
 204          *
 205          * We don't need to do anything special for the zone sizes, since the
 206          * default values that were already configured up above should be
 207          * satisfactory.
 208          */
 209         disable_mmu();
 210 #endif
 211         NODE_DATA(0)->node_mem_map = NULL;
 212         free_area_init_node(0, NODE_DATA(0), zones_size, __MEMORY_START >> PAGE_SHIFT, 0);
 213 }
 214
 215 void __init mem_init(void)
 216 {
 217         extern unsigned long empty_zero_page[1024];
 218         int codesize, reservedpages, datasize, initsize;
 219         int tmp;
 220         extern unsigned long memory_start;
 221
 222 #ifdef CONFIG_MMU
 223         high_memory = (void *)__va(MAX_LOW_PFN * PAGE_SIZE);
 224 #else
 225         extern unsigned long memory_end;
 226
 227         high_memory = (void *)(memory_end & PAGE_MASK);
 228 #endif
 229
 230         max_mapnr = num_physpages = MAP_NR(high_memory) - MAP_NR(memory_start);
 231
 232         /* clear the zero-page */
 233         memset(empty_zero_page, 0, PAGE_SIZE);
 234         __flush_wback_region(empty_zero_page, PAGE_SIZE);
 235
 236         /*
 237          * Setup wrappers for copy/clear_page(), these will get overridden
 238          * later in the boot process if a better method is available.
 239          */
 240         copy_page = copy_page_slow;
 241         clear_page = clear_page_slow;
 242
 243         /* this will put all low memory onto the freelists */
 244         totalram_pages += free_all_bootmem_node(NODE_DATA(0));
 245         reservedpages = 0;
 246         for (tmp = 0; tmp < num_physpages; tmp++)
 247                 /*
 248                  * Only count reserved RAM pages
 249                  */
 250                 if (PageReserved(mem_map+tmp))
 251                         reservedpages++;
 252
 253         codesize =  (unsigned long) &_etext - (unsigned long) &_text;
 254         datasize =  (unsigned long) &_edata - (unsigned long) &_etext;
 255         initsize =  (unsigned long) &__init_end - (unsigned long) &__init_begin;
 256
 257         printk("Memory: %luk/%luk available (%dk kernel code, %dk reserved, %dk data, %dk init)\n",
 258                 (unsigned long) nr_free_pages() << (PAGE_SHIFT-10),
 259                 max_mapnr << (PAGE_SHIFT-10),
 260                 codesize >> 10,
 261                 reservedpages << (PAGE_SHIFT-10),
 262                 datasize >> 10,
 263                 initsize >> 10);
 264
 265         p3_cache_init();
 266 }
 267
 268 void free_initmem(void)
 269 {
 270         unsigned long addr;
 271
 272         addr = (unsigned long)(&__init_begin);
 273         for (; addr < (unsigned long)(&__init_end); addr += PAGE_SIZE) {
 274                 ClearPageReserved(virt_to_page(addr));
 275                 init_page_count(virt_to_page(addr));
 276                 free_page(addr);
 277                 totalram_pages++;
 278         }
 279         printk ("Freeing unused kernel memory: %dk freed\n", (&__init_end - &__init_begin) >> 10);
 280 }
 281
 282 #ifdef CONFIG_BLK_DEV_INITRD
 283 void free_initrd_mem(unsigned long start, unsigned long end)
 284 {
 285         unsigned long p;
 286         for (p = start; p < end; p += PAGE_SIZE) {
 287                 ClearPageReserved(virt_to_page(p));
 288                 init_page_count(virt_to_page(p));
 289                 free_page(p);
 290                 totalram_pages++;
 291         }
 292         printk ("Freeing initrd memory: %ldk freed\n", (end - start) >> 10);
 293 }
 294 #endif
 295