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