arch/um/kernel/mem.c

   1 /*
   2  * Copyright (C) 2000 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
   3  * Licensed under the GPL
   4  */
   5
   6 #include <linux/stddef.h>
   7 #include <linux/module.h>
   8 #include <linux/bootmem.h>
   9 #include <linux/highmem.h>
  10 #include <linux/mm.h>
  11 #include <linux/swap.h>
  12 #include <linux/slab.h>
  13 #include <asm/fixmap.h>
  14 #include <asm/page.h>
  15 #include <as-layout.h>
  16 #include <init.h>
  17 #include <kern.h>
  18 #include <kern_util.h>
  19 #include <mem_user.h>
  20 #include <os.h>
  21
  22 /* allocated in paging_init, zeroed in mem_init, and unchanged thereafter */
  23 unsigned long *empty_zero_page = NULL;
  24 EXPORT_SYMBOL(empty_zero_page);
  25 /* allocated in paging_init and unchanged thereafter */
  26 static unsigned long *empty_bad_page = NULL;
  27
  28 /*
  29  * Initialized during boot, and readonly for initializing page tables
  30  * afterwards
  31  */
  32 pgd_t swapper_pg_dir[PTRS_PER_PGD];
  33
  34 /* Initialized at boot time, and readonly after that */
  35 unsigned long long highmem;
  36 int kmalloc_ok = 0;
  37
  38 /* Used during early boot */
  39 static unsigned long brk_end;
  40
  41 #ifdef CONFIG_HIGHMEM
  42 static void setup_highmem(unsigned long highmem_start,
  43                           unsigned long highmem_len)
  44 {
  45         unsigned long highmem_pfn;
  46         int i;
  47
  48         highmem_pfn = __pa(highmem_start) >> PAGE_SHIFT;
  49         for (i = 0; i < highmem_len >> PAGE_SHIFT; i++)
  50                 free_highmem_page(&mem_map[highmem_pfn + i]);
  51 }
  52 #endif
  53
  54 void __init mem_init(void)
  55 {
  56         /* clear the zero-page */
  57         memset(empty_zero_page, 0, PAGE_SIZE);
  58
  59         /* Map in the area just after the brk now that kmalloc is about
  60          * to be turned on.
  61          */
  62         brk_end = (unsigned long) UML_ROUND_UP(sbrk(0));
  63         map_memory(brk_end, __pa(brk_end), uml_reserved - brk_end, 1, 1, 0);
  64         free_bootmem(__pa(brk_end), uml_reserved - brk_end);
  65         uml_reserved = brk_end;
  66
  67         /* this will put all low memory onto the freelists */
  68         totalram_pages = free_all_bootmem();
  69         max_low_pfn = totalram_pages;
  70 #ifdef CONFIG_HIGHMEM
  71         setup_highmem(end_iomem, highmem);
  72 #endif
  73         num_physpages = totalram_pages;
  74         max_pfn = totalram_pages;
  75         printk(KERN_INFO "Memory: %luk available\n",
  76                nr_free_pages() << (PAGE_SHIFT-10));
  77         kmalloc_ok = 1;
  78 }
  79
  80 /*
  81  * Create a page table and place a pointer to it in a middle page
  82  * directory entry.
  83  */
  84 static void __init one_page_table_init(pmd_t *pmd)
  85 {
  86         if (pmd_none(*pmd)) {
  87                 pte_t *pte = (pte_t *) alloc_bootmem_low_pages(PAGE_SIZE);
  88                 set_pmd(pmd, __pmd(_KERNPG_TABLE +
  89                                            (unsigned long) __pa(pte)));
  90                 if (pte != pte_offset_kernel(pmd, 0))
  91                         BUG();
  92         }
  93 }
  94
  95 static void __init one_md_table_init(pud_t *pud)
  96 {
  97 #ifdef CONFIG_3_LEVEL_PGTABLES
  98         pmd_t *pmd_table = (pmd_t *) alloc_bootmem_low_pages(PAGE_SIZE);
  99         set_pud(pud, __pud(_KERNPG_TABLE + (unsigned long) __pa(pmd_table)));
 100         if (pmd_table != pmd_offset(pud, 0))
 101                 BUG();
 102 #endif
 103 }
 104
 105 static void __init fixrange_init(unsigned long start, unsigned long end,
 106                                  pgd_t *pgd_base)
 107 {
 108         pgd_t *pgd;
 109         pud_t *pud;
 110         pmd_t *pmd;
 111         int i, j;
 112         unsigned long vaddr;
 113
 114         vaddr = start;
 115         i = pgd_index(vaddr);
 116         j = pmd_index(vaddr);
 117         pgd = pgd_base + i;
 118
 119         for ( ; (i < PTRS_PER_PGD) && (vaddr < end); pgd++, i++) {
 120                 pud = pud_offset(pgd, vaddr);
 121                 if (pud_none(*pud))
 122                         one_md_table_init(pud);
 123                 pmd = pmd_offset(pud, vaddr);
 124                 for (; (j < PTRS_PER_PMD) && (vaddr < end); pmd++, j++) {
 125                         one_page_table_init(pmd);
 126                         vaddr += PMD_SIZE;
 127                 }
 128                 j = 0;
 129         }
 130 }
 131
 132 #ifdef CONFIG_HIGHMEM
 133 pte_t *kmap_pte;
 134 pgprot_t kmap_prot;
 135
 136 #define kmap_get_fixmap_pte(vaddr)                                      \
 137         pte_offset_kernel(pmd_offset(pud_offset(pgd_offset_k(vaddr), (vaddr)),\
 138                                      (vaddr)), (vaddr))
 139
 140 static void __init kmap_init(void)
 141 {
 142         unsigned long kmap_vstart;
 143
 144         /* cache the first kmap pte */
 145         kmap_vstart = __fix_to_virt(FIX_KMAP_BEGIN);
 146         kmap_pte = kmap_get_fixmap_pte(kmap_vstart);
 147
 148         kmap_prot = PAGE_KERNEL;
 149 }
 150
 151 static void __init init_highmem(void)
 152 {
 153         pgd_t *pgd;
 154         pud_t *pud;
 155         pmd_t *pmd;
 156         pte_t *pte;
 157         unsigned long vaddr;
 158
 159         /*
 160          * Permanent kmaps:
 161          */
 162         vaddr = PKMAP_BASE;
 163         fixrange_init(vaddr, vaddr + PAGE_SIZE*LAST_PKMAP, swapper_pg_dir);
 164
 165         pgd = swapper_pg_dir + pgd_index(vaddr);
 166         pud = pud_offset(pgd, vaddr);
 167         pmd = pmd_offset(pud, vaddr);
 168         pte = pte_offset_kernel(pmd, vaddr);
 169         pkmap_page_table = pte;
 170
 171         kmap_init();
 172 }
 173 #endif /* CONFIG_HIGHMEM */
 174
 175 static void __init fixaddr_user_init( void)
 176 {
 177 #ifdef CONFIG_ARCH_REUSE_HOST_VSYSCALL_AREA
 178         long size = FIXADDR_USER_END - FIXADDR_USER_START;
 179         pgd_t *pgd;
 180         pud_t *pud;
 181         pmd_t *pmd;
 182         pte_t *pte;
 183         phys_t p;
 184         unsigned long v, vaddr = FIXADDR_USER_START;
 185
 186         if (!size)
 187                 return;
 188
 189         fixrange_init( FIXADDR_USER_START, FIXADDR_USER_END, swapper_pg_dir);
 190         v = (unsigned long) alloc_bootmem_low_pages(size);
 191         memcpy((void *) v , (void *) FIXADDR_USER_START, size);
 192         p = __pa(v);
 193         for ( ; size > 0; size -= PAGE_SIZE, vaddr += PAGE_SIZE,
 194                       p += PAGE_SIZE) {
 195                 pgd = swapper_pg_dir + pgd_index(vaddr);
 196                 pud = pud_offset(pgd, vaddr);
 197                 pmd = pmd_offset(pud, vaddr);
 198                 pte = pte_offset_kernel(pmd, vaddr);
 199                 pte_set_val(*pte, p, PAGE_READONLY);
 200         }
 201 #endif
 202 }
 203
 204 void __init paging_init(void)
 205 {
 206         unsigned long zones_size[MAX_NR_ZONES], vaddr;
 207         int i;
 208
 209         empty_zero_page = (unsigned long *) alloc_bootmem_low_pages(PAGE_SIZE);
 210         empty_bad_page = (unsigned long *) alloc_bootmem_low_pages(PAGE_SIZE);
 211         for (i = 0; i < ARRAY_SIZE(zones_size); i++)
 212                 zones_size[i] = 0;
 213
 214         zones_size[ZONE_NORMAL] = (end_iomem >> PAGE_SHIFT) -
 215                 (uml_physmem >> PAGE_SHIFT);
 216 #ifdef CONFIG_HIGHMEM
 217         zones_size[ZONE_HIGHMEM] = highmem >> PAGE_SHIFT;
 218 #endif
 219         free_area_init(zones_size);
 220
 221         /*
 222          * Fixed mappings, only the page table structure has to be
 223          * created - mappings will be set by set_fixmap():
 224          */
 225         vaddr = __fix_to_virt(__end_of_fixed_addresses - 1) & PMD_MASK;
 226         fixrange_init(vaddr, FIXADDR_TOP, swapper_pg_dir);
 227
 228         fixaddr_user_init();
 229
 230 #ifdef CONFIG_HIGHMEM
 231         init_highmem();
 232 #endif
 233 }
 234
 235 /*
 236  * This can't do anything because nothing in the kernel image can be freed
 237  * since it's not in kernel physical memory.
 238  */
 239
 240 void free_initmem(void)
 241 {
 242 }
 243
 244 #ifdef CONFIG_BLK_DEV_INITRD
 245 void free_initrd_mem(unsigned long start, unsigned long end)
 246 {
 247         free_reserved_area(start, end, 0, "initrd");
 248 }
 249 #endif
 250
 251 /* Allocate and free page tables. */
 252
 253 pgd_t *pgd_alloc(struct mm_struct *mm)
 254 {
 255         pgd_t *pgd = (pgd_t *)__get_free_page(GFP_KERNEL);
 256
 257         if (pgd) {
 258                 memset(pgd, 0, USER_PTRS_PER_PGD * sizeof(pgd_t));
 259                 memcpy(pgd + USER_PTRS_PER_PGD,
 260                        swapper_pg_dir + USER_PTRS_PER_PGD,
 261                        (PTRS_PER_PGD - USER_PTRS_PER_PGD) * sizeof(pgd_t));
 262         }
 263         return pgd;
 264 }
 265
 266 void pgd_free(struct mm_struct *mm, pgd_t *pgd)
 267 {
 268         free_page((unsigned long) pgd);
 269 }
 270
 271 pte_t *pte_alloc_one_kernel(struct mm_struct *mm, unsigned long address)
 272 {
 273         pte_t *pte;
 274
 275         pte = (pte_t *)__get_free_page(GFP_KERNEL|__GFP_REPEAT|__GFP_ZERO);
 276         return pte;
 277 }
 278
 279 pgtable_t pte_alloc_one(struct mm_struct *mm, unsigned long address)
 280 {
 281         struct page *pte;
 282
 283         pte = alloc_page(GFP_KERNEL|__GFP_REPEAT|__GFP_ZERO);
 284         if (pte)
 285                 pgtable_page_ctor(pte);
 286         return pte;
 287 }
 288
 289 #ifdef CONFIG_3_LEVEL_PGTABLES
 290 pmd_t *pmd_alloc_one(struct mm_struct *mm, unsigned long address)
 291 {
 292         pmd_t *pmd = (pmd_t *) __get_free_page(GFP_KERNEL);
 293
 294         if (pmd)
 295                 memset(pmd, 0, PAGE_SIZE);
 296
 297         return pmd;
 298 }
 299 #endif
 300
 301 void *uml_kmalloc(int size, int flags)
 302 {
 303         return kmalloc(size, flags);
 304 }