arch/mips/mm/pgtable-32.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  * Copyright (C) 2003 by Ralf Baechle
   7  */
   8 #include <linux/config.h>
   9 #include <linux/init.h>
  10 #include <linux/mm.h>
  11 #include <linux/bootmem.h>
  12 #include <linux/highmem.h>
  13 #include <asm/pgtable.h>
  14
  15 void pgd_init(unsigned long page)
  16 {
  17         unsigned long *p = (unsigned long *) page;
  18         int i;
  19
  20         for (i = 0; i < USER_PTRS_PER_PGD; i+=8) {
  21                 p[i + 0] = (unsigned long) invalid_pte_table;
  22                 p[i + 1] = (unsigned long) invalid_pte_table;
  23                 p[i + 2] = (unsigned long) invalid_pte_table;
  24                 p[i + 3] = (unsigned long) invalid_pte_table;
  25                 p[i + 4] = (unsigned long) invalid_pte_table;
  26                 p[i + 5] = (unsigned long) invalid_pte_table;
  27                 p[i + 6] = (unsigned long) invalid_pte_table;
  28                 p[i + 7] = (unsigned long) invalid_pte_table;
  29         }
  30 }
  31
  32 #ifdef CONFIG_HIGHMEM
  33 static void __init fixrange_init (unsigned long start, unsigned long end,
  34         pgd_t *pgd_base)
  35 {
  36         pgd_t *pgd;
  37         pmd_t *pmd;
  38         pte_t *pte;
  39         int i, j;
  40         unsigned long vaddr;
  41
  42         vaddr = start;
  43         i = __pgd_offset(vaddr);
  44         j = __pmd_offset(vaddr);
  45         pgd = pgd_base + i;
  46
  47         for ( ; (i < PTRS_PER_PGD) && (vaddr != end); pgd++, i++) {
  48                 pmd = (pmd_t *)pgd;
  49                 for (; (j < PTRS_PER_PMD) && (vaddr != end); pmd++, j++) {
  50                         if (pmd_none(*pmd)) {
  51                                 pte = (pte_t *) alloc_bootmem_low_pages(PAGE_SIZE);
  52                                 set_pmd(pmd, __pmd((unsigned long)pte));
  53                                 if (pte != pte_offset_kernel(pmd, 0))
  54                                         BUG();
  55                         }
  56                         vaddr += PMD_SIZE;
  57                 }
  58                 j = 0;
  59         }
  60 }
  61 #endif
  62
  63 void __init pagetable_init(void)
  64 {
  65 #ifdef CONFIG_HIGHMEM
  66         unsigned long vaddr;
  67         pgd_t *pgd, *pgd_base;
  68         pmd_t *pmd;
  69         pte_t *pte;
  70 #endif
  71
  72         /* Initialize the entire pgd.  */
  73         pgd_init((unsigned long)swapper_pg_dir);
  74         pgd_init((unsigned long)swapper_pg_dir
  75                  + sizeof(pgd_t) * USER_PTRS_PER_PGD);
  76
  77 #ifdef CONFIG_HIGHMEM
  78         pgd_base = swapper_pg_dir;
  79
  80         /*
  81          * Fixed mappings:
  82          */
  83         vaddr = __fix_to_virt(__end_of_fixed_addresses - 1) & PMD_MASK;
  84         fixrange_init(vaddr, 0, pgd_base);
  85
  86         /*
  87          * Permanent kmaps:
  88          */
  89         vaddr = PKMAP_BASE;
  90         fixrange_init(vaddr, vaddr + PAGE_SIZE*LAST_PKMAP, pgd_base);
  91
  92         pgd = swapper_pg_dir + __pgd_offset(vaddr);
  93         pmd = pmd_offset(pgd, vaddr);
  94         pte = pte_offset_kernel(pmd, vaddr);
  95         pkmap_page_table = pte;
  96 #endif
  97 }