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