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   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/bootmem.h>
   8 #include <linux/gfp.h>
   9 #include <linux/highmem.h>
  10 #include <linux/mm.h>
  11 #include <linux/swap.h>
  12 #include <asm/fixmap.h>
  13 #include <asm/page.h>
  14 #include "as-layout.h"
  15 #include "init.h"
  16 #include "kern.h"
  17 #include "kern_util.h"
  18 #include "mem_user.h"
  19 #include "os.h"
  20
  21 /* allocated in paging_init, zeroed in mem_init, and unchanged thereafter */
  22 unsigned long *empty_zero_page = NULL;
  23 /* allocated in paging_init and unchanged thereafter */
  24 unsigned long *empty_bad_page = NULL;
  25
  26 /*
  27  * Initialized during boot, and readonly for initializing page tables
  28  * afterwards
  29  */
  30 pgd_t swapper_pg_dir[PTRS_PER_PGD];
  31
  32 /* Initialized at boot time, and readonly after that */
  33 unsigned long long highmem;
  34 int kmalloc_ok = 0;
  35
  36 /* Used during early boot */
  37 static unsigned long brk_end;
  38
  39 static void map_cb(void *unused)
  40 {
  41         map_memory(brk_end, __pa(brk_end), uml_reserved - brk_end, 1, 1, 0);
  42 }
  43
  44 #ifdef CONFIG_HIGHMEM
  45 static void setup_highmem(unsigned long highmem_start,
  46                           unsigned long highmem_len)
  47 {
  48         struct page *page;
  49         unsigned long highmem_pfn;
  50         int i;
  51
  52         highmem_pfn = __pa(highmem_start) >> PAGE_SHIFT;
  53         for (i = 0; i < highmem_len >> PAGE_SHIFT; i++) {
  54                 page = &mem_map[highmem_pfn + i];
  55                 ClearPageReserved(page);
  56                 init_page_count(page);
  57                 __free_page(page);
  58         }
  59 }
  60 #endif
  61
  62 void __init mem_init(void)
  63 {
  64         /* clear the zero-page */
  65         memset(empty_zero_page, 0, PAGE_SIZE);
  66
  67         /* Map in the area just after the brk now that kmalloc is about
  68          * to be turned on.
  69          */
  70         brk_end = (unsigned long) UML_ROUND_UP(sbrk(0));
  71         map_cb(NULL);
  72         initial_thread_cb(map_cb, NULL);
  73         free_bootmem(__pa(brk_end), uml_reserved - brk_end);
  74         uml_reserved = brk_end;
  75
  76         /* this will put all low memory onto the freelists */
  77         totalram_pages = free_all_bootmem();
  78         max_low_pfn = totalram_pages;
  79 #ifdef CONFIG_HIGHMEM
  80         totalhigh_pages = highmem >> PAGE_SHIFT;
  81         totalram_pages += totalhigh_pages;
  82 #endif
  83         num_physpages = totalram_pages;
  84         max_pfn = totalram_pages;
  85         printk(KERN_INFO "Memory: %luk available\n",
  86                (unsigned long) nr_free_pages() << (PAGE_SHIFT-10));
  87         kmalloc_ok = 1;
  88
  89 #ifdef CONFIG_HIGHMEM
  90         setup_highmem(end_iomem, highmem);
  91 #endif
  92 }
  93
  94 /*
  95  * Create a page table and place a pointer to it in a middle page
  96  * directory entry.
  97  */
  98 static void __init one_page_table_init(pmd_t *pmd)
  99 {
 100         if (pmd_none(*pmd)) {
 101                 pte_t *pte = (pte_t *) alloc_bootmem_low_pages(PAGE_SIZE);
 102                 set_pmd(pmd, __pmd(_KERNPG_TABLE +
 103                                            (unsigned long) __pa(pte)));
 104                 if (pte != pte_offset_kernel(pmd, 0))
 105                         BUG();
 106         }
 107 }
 108
 109 static void __init one_md_table_init(pud_t *pud)
 110 {
 111 #ifdef CONFIG_3_LEVEL_PGTABLES
 112         pmd_t *pmd_table = (pmd_t *) alloc_bootmem_low_pages(PAGE_SIZE);
 113         set_pud(pud, __pud(_KERNPG_TABLE + (unsigned long) __pa(pmd_table)));
 114         if (pmd_table != pmd_offset(pud, 0))
 115                 BUG();
 116 #endif
 117 }
 118
 119 static void __init fixrange_init(unsigned long start, unsigned long end,
 120                                  pgd_t *pgd_base)
 121 {
 122         pgd_t *pgd;
 123         pud_t *pud;
 124         pmd_t *pmd;
 125         int i, j;
 126         unsigned long vaddr;
 127
 128         vaddr = start;
 129         i = pgd_index(vaddr);
 130         j = pmd_index(vaddr);
 131         pgd = pgd_base + i;
 132
 133         for ( ; (i < PTRS_PER_PGD) && (vaddr < end); pgd++, i++) {
 134                 pud = pud_offset(pgd, vaddr);
 135                 if (pud_none(*pud))
 136                         one_md_table_init(pud);
 137                 pmd = pmd_offset(pud, vaddr);
 138                 for (; (j < PTRS_PER_PMD) && (vaddr < end); pmd++, j++) {
 139                         one_page_table_init(pmd);
 140                         vaddr += PMD_SIZE;
 141                 }
 142                 j = 0;
 143         }
 144 }
 145
 146 #ifdef CONFIG_HIGHMEM
 147 pte_t *kmap_pte;
 148 pgprot_t kmap_prot;
 149
 150 #define kmap_get_fixmap_pte(vaddr)                                      \
 151         pte_offset_kernel(pmd_offset(pud_offset(pgd_offset_k(vaddr), (vaddr)),\
 152                                      (vaddr)), (vaddr))
 153
 154 static void __init kmap_init(void)
 155 {
 156         unsigned long kmap_vstart;
 157
 158         /* cache the first kmap pte */
 159         kmap_vstart = __fix_to_virt(FIX_KMAP_BEGIN);
 160         kmap_pte = kmap_get_fixmap_pte(kmap_vstart);
 161
 162         kmap_prot = PAGE_KERNEL;
 163 }
 164
 165 static void __init init_highmem(void)
 166 {
 167         pgd_t *pgd;
 168         pud_t *pud;
 169         pmd_t *pmd;
 170         pte_t *pte;
 171         unsigned long vaddr;
 172
 173         /*
 174          * Permanent kmaps:
 175          */
 176         vaddr = PKMAP_BASE;
 177         fixrange_init(vaddr, vaddr + PAGE_SIZE*LAST_PKMAP, swapper_pg_dir);
 178
 179         pgd = swapper_pg_dir + pgd_index(vaddr);
 180         pud = pud_offset(pgd, vaddr);
 181         pmd = pmd_offset(pud, vaddr);
 182         pte = pte_offset_kernel(pmd, vaddr);
 183         pkmap_page_table = pte;
 184
 185         kmap_init();
 186 }
 187 #endif /* CONFIG_HIGHMEM */
 188
 189 static void __init fixaddr_user_init( void)
 190 {
 191 #ifdef CONFIG_ARCH_REUSE_HOST_VSYSCALL_AREA
 192         long size = FIXADDR_USER_END - FIXADDR_USER_START;
 193         pgd_t *pgd;
 194         pud_t *pud;
 195         pmd_t *pmd;
 196         pte_t *pte;
 197         phys_t p;
 198         unsigned long v, vaddr = FIXADDR_USER_START;
 199
 200         if (!size)
 201                 return;
 202
 203         fixrange_init( FIXADDR_USER_START, FIXADDR_USER_END, swapper_pg_dir);
 204         v = (unsigned long) alloc_bootmem_low_pages(size);
 205         memcpy((void *) v , (void *) FIXADDR_USER_START, size);
 206         p = __pa(v);
 207         for ( ; size > 0; size -= PAGE_SIZE, vaddr += PAGE_SIZE,
 208                       p += PAGE_SIZE) {
 209                 pgd = swapper_pg_dir + pgd_index(vaddr);
 210                 pud = pud_offset(pgd, vaddr);
 211                 pmd = pmd_offset(pud, vaddr);
 212                 pte = pte_offset_kernel(pmd, vaddr);
 213                 pte_set_val(*pte, p, PAGE_READONLY);
 214         }
 215 #endif
 216 }
 217
 218 void __init paging_init(void)
 219 {
 220         unsigned long zones_size[MAX_NR_ZONES], vaddr;
 221         int i;
 222
 223         empty_zero_page = (unsigned long *) alloc_bootmem_low_pages(PAGE_SIZE);
 224         empty_bad_page = (unsigned long *) alloc_bootmem_low_pages(PAGE_SIZE);
 225         for (i = 0; i < ARRAY_SIZE(zones_size); i++)
 226                 zones_size[i] = 0;
 227
 228         zones_size[ZONE_NORMAL] = (end_iomem >> PAGE_SHIFT) -
 229                 (uml_physmem >> PAGE_SHIFT);
 230 #ifdef CONFIG_HIGHMEM
 231         zones_size[ZONE_HIGHMEM] = highmem >> PAGE_SHIFT;
 232 #endif
 233         free_area_init(zones_size);
 234
 235         /*
 236          * Fixed mappings, only the page table structure has to be
 237          * created - mappings will be set by set_fixmap():
 238          */
 239         vaddr = __fix_to_virt(__end_of_fixed_addresses - 1) & PMD_MASK;
 240         fixrange_init(vaddr, FIXADDR_TOP, swapper_pg_dir);
 241
 242         fixaddr_user_init();
 243
 244 #ifdef CONFIG_HIGHMEM
 245         init_highmem();
 246 #endif
 247 }
 248
 249 struct page *arch_validate(struct page *page, gfp_t mask, int order)
 250 {
 251         unsigned long addr, zero = 0;
 252         int i;
 253
 254  again:
 255         if (page == NULL)
 256                 return page;
 257         if (PageHighMem(page))
 258                 return page;
 259
 260         addr = (unsigned long) page_address(page);
 261         for (i = 0; i < (1 << order); i++) {
 262                 current->thread.fault_addr = (void *) addr;
 263                 if (__do_copy_to_user((void __user *) addr, &zero,
 264                                      sizeof(zero),
 265                                      &current->thread.fault_addr,
 266                                      &current->thread.fault_catcher)) {
 267                         if (!(mask & __GFP_WAIT))
 268                                 return NULL;
 269                         else break;
 270                 }
 271                 addr += PAGE_SIZE;
 272         }
 273
 274         if (i == (1 << order))
 275                 return page;
 276         page = alloc_pages(mask, order);
 277         goto again;
 278 }
 279
 280 /*
 281  * This can't do anything because nothing in the kernel image can be freed
 282  * since it's not in kernel physical memory.
 283  */
 284
 285 void free_initmem(void)
 286 {
 287 }
 288
 289 #ifdef CONFIG_BLK_DEV_INITRD
 290 void free_initrd_mem(unsigned long start, unsigned long end)
 291 {
 292         if (start < end)
 293                 printk(KERN_INFO "Freeing initrd memory: %ldk freed\n",
 294                        (end - start) >> 10);
 295         for (; start < end; start += PAGE_SIZE) {
 296                 ClearPageReserved(virt_to_page(start));
 297                 init_page_count(virt_to_page(start));
 298                 free_page(start);
 299                 totalram_pages++;
 300         }
 301 }
 302 #endif
 303
 304 void show_mem(void)
 305 {
 306         int pfn, total = 0, reserved = 0;
 307         int shared = 0, cached = 0;
 308         int highmem = 0;
 309         struct page *page;
 310
 311         printk(KERN_INFO "Mem-info:\n");
 312         show_free_areas();
 313         printk(KERN_INFO "Free swap:       %6ldkB\n",
 314                nr_swap_pages<<(PAGE_SHIFT-10));
 315         pfn = max_mapnr;
 316         while (pfn-- > 0) {
 317                 page = pfn_to_page(pfn);
 318                 total++;
 319                 if (PageHighMem(page))
 320                         highmem++;
 321                 if (PageReserved(page))
 322                         reserved++;
 323                 else if (PageSwapCache(page))
 324                         cached++;
 325                 else if (page_count(page))
 326                         shared += page_count(page) - 1;
 327         }
 328         printk(KERN_INFO "%d pages of RAM\n", total);
 329         printk(KERN_INFO "%d pages of HIGHMEM\n", highmem);
 330         printk(KERN_INFO "%d reserved pages\n", reserved);
 331         printk(KERN_INFO "%d pages shared\n", shared);
 332         printk(KERN_INFO "%d pages swap cached\n", cached);
 333 }
 334
 335 /* Allocate and free page tables. */
 336
 337 pgd_t *pgd_alloc(struct mm_struct *mm)
 338 {
 339         pgd_t *pgd = (pgd_t *)__get_free_page(GFP_KERNEL);
 340
 341         if (pgd) {
 342                 memset(pgd, 0, USER_PTRS_PER_PGD * sizeof(pgd_t));
 343                 memcpy(pgd + USER_PTRS_PER_PGD,
 344                        swapper_pg_dir + USER_PTRS_PER_PGD,
 345                        (PTRS_PER_PGD - USER_PTRS_PER_PGD) * sizeof(pgd_t));
 346         }
 347         return pgd;
 348 }
 349
 350 void pgd_free(struct mm_struct *mm, pgd_t *pgd)
 351 {
 352         free_page((unsigned long) pgd);
 353 }
 354
 355 pte_t *pte_alloc_one_kernel(struct mm_struct *mm, unsigned long address)
 356 {
 357         pte_t *pte;
 358
 359         pte = (pte_t *)__get_free_page(GFP_KERNEL|__GFP_REPEAT|__GFP_ZERO);
 360         return pte;
 361 }
 362
 363 struct page *pte_alloc_one(struct mm_struct *mm, unsigned long address)
 364 {
 365         struct page *pte;
 366
 367         pte = alloc_page(GFP_KERNEL|__GFP_REPEAT|__GFP_ZERO);
 368         return pte;
 369 }
 370
 371 #ifdef CONFIG_3_LEVEL_PGTABLES
 372 pmd_t *pmd_alloc_one(struct mm_struct *mm, unsigned long address)
 373 {
 374         pmd_t *pmd = (pmd_t *) __get_free_page(GFP_KERNEL);
 375
 376         if (pmd)
 377                 memset(pmd, 0, PAGE_SIZE);
 378
 379         return pmd;
 380 }
 381 #endif