arch/sh/mm/init.c

   1 /* $Id: init.c,v 1.17 2000-04-08 15:38:54+09 gniibe Exp $
   2  *
   3  *  linux/arch/sh/mm/init.c
   4  *
   5  *  Copyright (C) 1999  Niibe Yutaka
   6  *
   7  *  Based on linux/arch/i386/mm/init.c:
   8  *   Copyright (C) 1995  Linus Torvalds
   9  */
  10
  11 #include <linux/config.h>
  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 #ifdef CONFIG_BLK_DEV_INITRD
  25 #include <linux/blk.h>
  26 #endif
  27 #include <linux/highmem.h>
  28 #include <linux/bootmem.h>
  29
  30 #include <asm/processor.h>
  31 #include <asm/system.h>
  32 #include <asm/uaccess.h>
  33 #include <asm/pgtable.h>
  34 #include <asm/pgalloc.h>
  35 #include <asm/mmu_context.h>
  36 #include <asm/io.h>
  37
  38 /*
  39  * Cache of MMU context last used.
  40  */
  41 unsigned long mmu_context_cache;
  42
  43 static unsigned long totalram_pages;
  44 static unsigned long totalhigh_pages;
  45
  46 extern unsigned long init_smp_mappings(unsigned long);
  47
  48 /*
  49  * BAD_PAGE is the page that is used for page faults when linux
  50  * is out-of-memory. Older versions of linux just did a
  51  * do_exit(), but using this instead means there is less risk
  52  * for a process dying in kernel mode, possibly leaving an inode
  53  * unused etc..
  54  *
  55  * BAD_PAGETABLE is the accompanying page-table: it is initialized
  56  * to point to BAD_PAGE entries.
  57  *
  58  * ZERO_PAGE is a special page that is used for zero-initialized
  59  * data and COW.
  60  */
  61
  62 unsigned long empty_bad_page[1024];
  63 pte_t empty_bad_pte_table[PTRS_PER_PTE];
  64 extern unsigned long empty_zero_page[1024];
  65
  66 static pte_t * get_bad_pte_table(void)
  67 {
  68         pte_t v;
  69         int i;
  70
  71         v = pte_mkdirty(mk_pte_phys(__pa(empty_bad_page), PAGE_SHARED));
  72
  73         for (i = 0; i < PAGE_SIZE/sizeof(pte_t); i++)
  74                 empty_bad_pte_table[i] = v;
  75
  76         return empty_bad_pte_table;
  77 }
  78
  79 void __handle_bad_pmd(pmd_t *pmd)
  80 {
  81         pmd_ERROR(*pmd);
  82         set_pmd(pmd, __pmd(_PAGE_TABLE + __pa(get_bad_pte_table())));
  83 }
  84
  85 void __handle_bad_pmd_kernel(pmd_t *pmd)
  86 {
  87         pmd_ERROR(*pmd);
  88         set_pmd(pmd, __pmd(_KERNPG_TABLE + __pa(get_bad_pte_table())));
  89 }
  90
  91 pte_t *get_pte_kernel_slow(pmd_t *pmd, unsigned long offset)
  92 {
  93         pte_t *pte;
  94
  95         pte = (pte_t *) __get_free_page(GFP_KERNEL);
  96         if (pmd_none(*pmd)) {
  97                 if (pte) {
  98                         clear_page(pte);
  99                         set_pmd(pmd, __pmd(_KERNPG_TABLE + __pa(pte)));
 100                         return pte + offset;
 101                 }
 102                 set_pmd(pmd, __pmd(_KERNPG_TABLE + __pa(get_bad_pte_table())));
 103                 return NULL;
 104         }
 105         free_page((unsigned long)pte);
 106         if (pmd_bad(*pmd)) {
 107                 __handle_bad_pmd_kernel(pmd);
 108                 return NULL;
 109         }
 110         return (pte_t *) pmd_page(*pmd) + offset;
 111 }
 112
 113 pte_t *get_pte_slow(pmd_t *pmd, unsigned long offset)
 114 {
 115         unsigned long pte;
 116
 117         pte = (unsigned long) __get_free_page(GFP_KERNEL);
 118         if (pmd_none(*pmd)) {
 119                 if (pte) {
 120                         clear_page((void *)pte);
 121                         set_pmd(pmd, __pmd(_PAGE_TABLE + __pa(pte)));
 122                         return (pte_t *)pte + offset;
 123                 }
 124                 set_pmd(pmd, __pmd(_PAGE_TABLE + __pa(get_bad_pte_table())));
 125                 return NULL;
 126         }
 127         free_page(pte);
 128         if (pmd_bad(*pmd)) {
 129                 __handle_bad_pmd(pmd);
 130                 return NULL;
 131         }
 132         return (pte_t *) pmd_page(*pmd) + offset;
 133 }
 134
 135 int do_check_pgt_cache(int low, int high)
 136 {
 137         int freed = 0;
 138         if (pgtable_cache_size > high) {
 139                 do {
 140                         if (pgd_quicklist)
 141                                 free_pgd_slow(get_pgd_fast()), freed++;
 142                         if (pmd_quicklist)
 143                                 free_pmd_slow(get_pmd_fast()), freed++;
 144                         if (pte_quicklist)
 145                                 free_pte_slow(get_pte_fast()), freed++;
 146                 } while (pgtable_cache_size > low);
 147         }
 148         return freed;
 149 }
 150
 151 void show_mem(void)
 152 {
 153         int i, total = 0, reserved = 0;
 154         int shared = 0, cached = 0;
 155
 156         printk("Mem-info:\n");
 157         show_free_areas();
 158         printk("Free swap:       %6dkB\n",nr_swap_pages<<(PAGE_SHIFT-10));
 159         i = max_mapnr;
 160         while (i-- > 0) {
 161                 total++;
 162                 if (PageReserved(mem_map+i))
 163                         reserved++;
 164                 else if (PageSwapCache(mem_map+i))
 165                         cached++;
 166                 else if (page_count(mem_map+i))
 167                         shared += page_count(mem_map+i) - 1;
 168         }
 169         printk("%d pages of RAM\n",total);
 170         printk("%d reserved pages\n",reserved);
 171         printk("%d pages shared\n",shared);
 172         printk("%d pages swap cached\n",cached);
 173         printk("%ld pages in page table cache\n",pgtable_cache_size);
 174         show_buffers();
 175 }
 176
 177 /* References to section boundaries */
 178
 179 extern char _text, _etext, _edata, __bss_start, _end;
 180 extern char __init_begin, __init_end;
 181
 182 pgd_t swapper_pg_dir[1024];
 183
 184 /* It'd be good if these lines were in the standard header file. */
 185 #define START_PFN       (NODE_DATA(0)->bdata->node_boot_start >> PAGE_SHIFT)
 186 #define MAX_LOW_PFN     (NODE_DATA(0)->bdata->node_low_pfn)
 187
 188 /*
 189  * paging_init() sets up the page tables
 190  *
 191  * This routines also unmaps the page at virtual kernel address 0, so
 192  * that we can trap those pesky NULL-reference errors in the kernel.
 193  */
 194 void __init paging_init(void)
 195 {
 196         int i;
 197         pgd_t * pg_dir;
 198
 199         /* We don't need kernel mapping as hardware support that. */
 200         pg_dir = swapper_pg_dir;
 201
 202         for (i=0; i < USER_PTRS_PER_PGD*2; i++)
 203                 pgd_val(pg_dir[i]) = 0;
 204
 205         /* Enable MMU */
 206         ctrl_outl(MMU_CONTROL_INIT, MMUCR);
 207
 208         /* The manual suggests doing some nops after turning on the MMU */
 209         asm volatile("nop;nop;nop;nop;nop;nop;");
 210
 211         mmu_context_cache = MMU_CONTEXT_FIRST_VERSION;
 212         set_asid(mmu_context_cache & MMU_CONTEXT_ASID_MASK);
 213
 214         {
 215                 unsigned long zones_size[MAX_NR_ZONES] = {0, 0, 0};
 216                 unsigned long max_dma, low, start_pfn;
 217
 218                 start_pfn = START_PFN;
 219                 max_dma = virt_to_phys((char *)MAX_DMA_ADDRESS) >> PAGE_SHIFT;
 220                 low = MAX_LOW_PFN;
 221
 222                 if (low < max_dma)
 223                         zones_size[ZONE_DMA] = low - start_pfn;
 224                 else {
 225                         zones_size[ZONE_DMA] = max_dma - start_pfn;
 226                         zones_size[ZONE_NORMAL] = low - max_dma;
 227                 }
 228                 free_area_init_node(0, 0, 0, zones_size, __MEMORY_START, 0);
 229         }
 230 }
 231
 232 void __init mem_init(void)
 233 {
 234         int codesize, reservedpages, datasize, initsize;
 235         int tmp;
 236
 237         max_mapnr = num_physpages = MAX_LOW_PFN - START_PFN;
 238         high_memory = (void *)__va(MAX_LOW_PFN * PAGE_SIZE);
 239
 240         /* clear the zero-page */
 241         memset(empty_zero_page, 0, PAGE_SIZE);
 242         flush_page_to_ram(virt_to_page(empty_zero_page));
 243
 244         /* this will put all low memory onto the freelists */
 245         totalram_pages += free_all_bootmem();
 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         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
 266 void free_initmem(void)
 267 {
 268         unsigned long addr;
 269
 270         addr = (unsigned long)(&__init_begin);
 271         for (; addr < (unsigned long)(&__init_end); addr += PAGE_SIZE) {
 272                 ClearPageReserved(virt_to_page(addr));
 273                 set_page_count(virt_to_page(addr), 1);
 274                 free_page(addr);
 275                 totalram_pages++;
 276         }
 277         printk ("Freeing unused kernel memory: %dk freed\n", (&__init_end - &__init_begin) >> 10);
 278 }
 279
 280 #ifdef CONFIG_BLK_DEV_INITRD
 281 void free_initrd_mem(unsigned long start, unsigned long end)
 282 {
 283         unsigned long p;
 284         for (p = start; p < end; p += PAGE_SIZE) {
 285                 ClearPageReserved(virt_to_page(p));
 286                 set_page_count(virt_to_page(p), 1);
 287                 free_page(p);
 288                 totalram_pages++;
 289         }
 290         printk ("Freeing initrd memory: %ldk freed\n", (end - start) >> 10);
 291 }
 292 #endif
 293
 294 void si_meminfo(struct sysinfo *val)
 295 {
 296         val->totalram = totalram_pages;
 297         val->sharedram = 0;
 298         val->freeram = nr_free_pages();
 299         val->bufferram = atomic_read(&buffermem_pages);
 300         val->totalhigh = totalhigh_pages;
 301         val->freehigh = nr_free_highpages();
 302         val->mem_unit = PAGE_SIZE;
 303         return;
 304 }