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/config.h>
  13 #include <linux/signal.h>
  14 #include <linux/sched.h>
  15 #include <linux/kernel.h>
  16 #include <linux/errno.h>
  17 #include <linux/string.h>
  18 #include <linux/types.h>
  19 #include <linux/ptrace.h>
  20 #include <linux/mman.h>
  21 #include <linux/mm.h>
  22 #include <linux/swap.h>
  23 #include <linux/smp.h>
  24 #include <linux/init.h>
  25 #include <linux/highmem.h>
  26 #include <linux/bootmem.h>
  27 #include <linux/pagemap.h>
  28
  29 #include <asm/processor.h>
  30 #include <asm/system.h>
  31 #include <asm/uaccess.h>
  32 #include <asm/pgtable.h>
  33 #include <asm/pgalloc.h>
  34 #include <asm/mmu_context.h>
  35 #include <asm/io.h>
  36 #include <asm/tlb.h>
  37 #include <asm/cacheflush.h>
  38 #include <asm/cache.h>
  39
  40 DEFINE_PER_CPU(struct mmu_gather, mmu_gathers);
  41 pgd_t swapper_pg_dir[PTRS_PER_PGD];
  42
  43 /*
  44  * Cache of MMU context last used.
  45  */
  46 unsigned long mmu_context_cache = NO_CONTEXT;
  47
  48 #ifdef CONFIG_MMU
  49 /* It'd be good if these lines were in the standard header file. */
  50 #define START_PFN       (NODE_DATA(0)->bdata->node_boot_start >> PAGE_SHIFT)
  51 #define MAX_LOW_PFN     (NODE_DATA(0)->bdata->node_low_pfn)
  52 #endif
  53
  54 #ifdef CONFIG_DISCONTIGMEM
  55 pg_data_t discontig_page_data[MAX_NUMNODES];
  56 bootmem_data_t discontig_node_bdata[MAX_NUMNODES];
  57 #endif
  58
  59 void (*copy_page)(void *from, void *to);
  60 void (*clear_page)(void *to);
  61
  62 void show_mem(void)
  63 {
  64         int i, total = 0, reserved = 0;
  65         int shared = 0, cached = 0;
  66
  67         printk("Mem-info:\n");
  68         show_free_areas();
  69         printk("Free swap:       %6ldkB\n", nr_swap_pages<<(PAGE_SHIFT-10));
  70         i = max_mapnr;
  71         while (i-- > 0) {
  72                 total++;
  73                 if (PageReserved(mem_map+i))
  74                         reserved++;
  75                 else if (PageSwapCache(mem_map+i))
  76                         cached++;
  77                 else if (page_count(mem_map+i))
  78                         shared += page_count(mem_map+i) - 1;
  79         }
  80         printk("%d pages of RAM\n",total);
  81         printk("%d reserved pages\n",reserved);
  82         printk("%d pages shared\n",shared);
  83         printk("%d pages swap cached\n",cached);
  84 }
  85
  86 static void set_pte_phys(unsigned long addr, unsigned long phys, pgprot_t prot)
  87 {
  88         pgd_t *pgd;
  89         pmd_t *pmd;
  90         pte_t *pte;
  91
  92         pgd = swapper_pg_dir + pgd_index(addr);
  93         if (pgd_none(*pgd)) {
  94                 pgd_ERROR(*pgd);
  95                 return;
  96         }
  97
  98         pmd = pmd_offset(pgd, addr);
  99         if (pmd_none(*pmd)) {
 100                 pte = (pte_t *)get_zeroed_page(GFP_ATOMIC);
 101                 set_pmd(pmd, __pmd(__pa(pte) | _KERNPG_TABLE | _PAGE_USER));
 102                 if (pte != pte_offset_kernel(pmd, 0)) {
 103                         pmd_ERROR(*pmd);
 104                         return;
 105                 }
 106         }
 107
 108         pte = pte_offset_kernel(pmd, addr);
 109         if (!pte_none(*pte)) {
 110                 pte_ERROR(*pte);
 111                 return;
 112         }
 113
 114         set_pte(pte, pfn_pte(phys >> PAGE_SHIFT, prot));
 115
 116         __flush_tlb_page(get_asid(), addr);
 117 }
 118
 119 /*
 120  * As a performance optimization, other platforms preserve the fixmap mapping
 121  * across a context switch, we don't presently do this, but this could be done
 122  * in a similar fashion as to the wired TLB interface that sh64 uses (by way
 123  * of the memorry mapped UTLB configuration) -- this unfortunately forces us to
 124  * give up a TLB entry for each mapping we want to preserve. While this may be
 125  * viable for a small number of fixmaps, it's not particularly useful for
 126  * everything and needs to be carefully evaluated. (ie, we may want this for
 127  * the vsyscall page).
 128  *
 129  * XXX: Perhaps add a _PAGE_WIRED flag or something similar that we can pass
 130  * in at __set_fixmap() time to determine the appropriate behavior to follow.
 131  *
 132  *                                       -- PFM.
 133  */
 134 void __set_fixmap(enum fixed_addresses idx, unsigned long phys, pgprot_t prot)
 135 {
 136         unsigned long address = __fix_to_virt(idx);
 137
 138         if (idx >= __end_of_fixed_addresses) {
 139                 BUG();
 140                 return;
 141         }
 142
 143         set_pte_phys(address, phys, prot);
 144 }
 145
 146 /* References to section boundaries */
 147
 148 extern char _text, _etext, _edata, __bss_start, _end;
 149 extern char __init_begin, __init_end;
 150
 151 /*
 152  * paging_init() sets up the page tables
 153  *
 154  * This routines also unmaps the page at virtual kernel address 0, so
 155  * that we can trap those pesky NULL-reference errors in the kernel.
 156  */
 157 void __init paging_init(void)
 158 {
 159         unsigned long zones_size[MAX_NR_ZONES] = { 0, };
 160
 161         /*
 162          * Setup some defaults for the zone sizes.. these should be safe
 163          * regardless of distcontiguous memory or MMU settings.
 164          */
 165         zones_size[ZONE_DMA] = 0 >> PAGE_SHIFT;
 166         zones_size[ZONE_NORMAL] = __MEMORY_SIZE >> PAGE_SHIFT;
 167 #ifdef CONFIG_HIGHMEM
 168         zones_size[ZONE_HIGHMEM] = 0 >> PAGE_SHIFT;
 169 #endif
 170
 171 #ifdef CONFIG_MMU
 172         /*
 173          * If we have an MMU, and want to be using it .. we need to adjust
 174          * the zone sizes accordingly, in addition to turning it on.
 175          */
 176         {
 177                 unsigned long max_dma, low, start_pfn;
 178                 pgd_t *pg_dir;
 179                 int i;
 180
 181                 /* We don't need kernel mapping as hardware support that. */
 182                 pg_dir = swapper_pg_dir;
 183
 184                 for (i = 0; i < PTRS_PER_PGD; i++)
 185                         pgd_val(pg_dir[i]) = 0;
 186
 187                 /* Turn on the MMU */
 188                 enable_mmu();
 189
 190                 /* Fixup the zone sizes */
 191                 start_pfn = START_PFN;
 192                 max_dma = virt_to_phys((char *)MAX_DMA_ADDRESS) >> PAGE_SHIFT;
 193                 low = MAX_LOW_PFN;
 194
 195                 if (low < max_dma) {
 196                         zones_size[ZONE_DMA] = low - start_pfn;
 197                         zones_size[ZONE_NORMAL] = 0;
 198                 } else {
 199                         zones_size[ZONE_DMA] = max_dma - start_pfn;
 200                         zones_size[ZONE_NORMAL] = low - max_dma;
 201                 }
 202         }
 203
 204 #elif defined(CONFIG_CPU_SH3) || defined(CONFIG_CPU_SH4)
 205         /*
 206          * If we don't have CONFIG_MMU set and the processor in question
 207          * still has an MMU, care needs to be taken to make sure it doesn't
 208          * stay on.. Since the boot loader could have potentially already
 209          * turned it on, and we clearly don't want it, we simply turn it off.
 210          *
 211          * We don't need to do anything special for the zone sizes, since the
 212          * default values that were already configured up above should be
 213          * satisfactory.
 214          */
 215         disable_mmu();
 216 #endif
 217         NODE_DATA(0)->node_mem_map = NULL;
 218         free_area_init_node(0, NODE_DATA(0), zones_size, __MEMORY_START >> PAGE_SHIFT, 0);
 219
 220 #ifdef CONFIG_DISCONTIGMEM
 221         /*
 222          * And for discontig, do some more fixups on the zone sizes..
 223          */
 224         zones_size[ZONE_DMA] = __MEMORY_SIZE_2ND >> PAGE_SHIFT;
 225         zones_size[ZONE_NORMAL] = 0;
 226         free_area_init_node(1, NODE_DATA(1), zones_size, __MEMORY_START_2ND >> PAGE_SHIFT, 0);
 227 #endif
 228 }
 229
 230 void __init mem_init(void)
 231 {
 232         extern unsigned long empty_zero_page[1024];
 233         int codesize, reservedpages, datasize, initsize;
 234         int tmp;
 235         extern unsigned long memory_start;
 236
 237 #ifdef CONFIG_MMU
 238         high_memory = (void *)__va(MAX_LOW_PFN * PAGE_SIZE);
 239 #else
 240         extern unsigned long memory_end;
 241
 242         high_memory = (void *)(memory_end & PAGE_MASK);
 243 #endif
 244
 245         max_mapnr = num_physpages = MAP_NR(high_memory) - MAP_NR(memory_start);
 246
 247         /* clear the zero-page */
 248         memset(empty_zero_page, 0, PAGE_SIZE);
 249         __flush_wback_region(empty_zero_page, PAGE_SIZE);
 250
 251         /*
 252          * Setup wrappers for copy/clear_page(), these will get overridden
 253          * later in the boot process if a better method is available.
 254          */
 255         copy_page = copy_page_slow;
 256         clear_page = clear_page_slow;
 257
 258         /* this will put all low memory onto the freelists */
 259         totalram_pages += free_all_bootmem_node(NODE_DATA(0));
 260 #ifdef CONFIG_DISCONTIGMEM
 261         totalram_pages += free_all_bootmem_node(NODE_DATA(1));
 262 #endif
 263         reservedpages = 0;
 264         for (tmp = 0; tmp < num_physpages; tmp++)
 265                 /*
 266                  * Only count reserved RAM pages
 267                  */
 268                 if (PageReserved(mem_map+tmp))
 269                         reservedpages++;
 270
 271         codesize =  (unsigned long) &_etext - (unsigned long) &_text;
 272         datasize =  (unsigned long) &_edata - (unsigned long) &_etext;
 273         initsize =  (unsigned long) &__init_end - (unsigned long) &__init_begin;
 274
 275         printk("Memory: %luk/%luk available (%dk kernel code, %dk reserved, %dk data, %dk init)\n",
 276                 (unsigned long) nr_free_pages() << (PAGE_SHIFT-10),
 277                 max_mapnr << (PAGE_SHIFT-10),
 278                 codesize >> 10,
 279                 reservedpages << (PAGE_SHIFT-10),
 280                 datasize >> 10,
 281                 initsize >> 10);
 282
 283         p3_cache_init();
 284 }
 285
 286 void free_initmem(void)
 287 {
 288         unsigned long addr;
 289
 290         addr = (unsigned long)(&__init_begin);
 291         for (; addr < (unsigned long)(&__init_end); addr += PAGE_SIZE) {
 292                 ClearPageReserved(virt_to_page(addr));
 293                 set_page_count(virt_to_page(addr), 1);
 294                 free_page(addr);
 295                 totalram_pages++;
 296         }
 297         printk ("Freeing unused kernel memory: %dk freed\n", (&__init_end - &__init_begin) >> 10);
 298 }
 299
 300 #ifdef CONFIG_BLK_DEV_INITRD
 301 void free_initrd_mem(unsigned long start, unsigned long end)
 302 {
 303         unsigned long p;
 304         for (p = start; p < end; p += PAGE_SIZE) {
 305                 ClearPageReserved(virt_to_page(p));
 306                 set_page_count(virt_to_page(p), 1);
 307                 free_page(p);
 308                 totalram_pages++;
 309         }
 310         printk ("Freeing initrd memory: %ldk freed\n", (end - start) >> 10);
 311 }
 312 #endif
 313