arch/um/kernel/mem.c

   1 /*
   2  * Copyright (C) 2000 - 2003 Jeff Dike (jdike@addtoit.com)
   3  * Licensed under the GPL
   4  */
   5
   6 #include "linux/stddef.h"
   7 #include "linux/kernel.h"
   8 #include "linux/mm.h"
   9 #include "linux/bootmem.h"
  10 #include "linux/swap.h"
  11 #include "linux/highmem.h"
  12 #include "linux/gfp.h"
  13 #include "asm/page.h"
  14 #include "asm/fixmap.h"
  15 #include "asm/pgalloc.h"
  16 #include "kern_util.h"
  17 #include "as-layout.h"
  18 #include "kern.h"
  19 #include "mem_user.h"
  20 #include "uml_uaccess.h"
  21 #include "os.h"
  22 #include "linux/types.h"
  23 #include "linux/string.h"
  24 #include "init.h"
  25 #include "kern_constants.h"
  26
  27 /* allocated in paging_init, zeroed in mem_init, and unchanged thereafter */
  28 unsigned long *empty_zero_page = NULL;
  29 /* allocated in paging_init and unchanged thereafter */
  30 unsigned long *empty_bad_page = NULL;
  31 pgd_t swapper_pg_dir[PTRS_PER_PGD];
  32 unsigned long long highmem;
  33 int kmalloc_ok = 0;
  34
  35 static unsigned long brk_end;
  36
  37 void unmap_physmem(void)
  38 {
  39         os_unmap_memory((void *) brk_end, uml_reserved - brk_end);
  40 }
  41
  42 static void map_cb(void *unused)
  43 {
  44         map_memory(brk_end, __pa(brk_end), uml_reserved - brk_end, 1, 1, 0);
  45 }
  46
  47 #ifdef CONFIG_HIGHMEM
  48 static void setup_highmem(unsigned long highmem_start,
  49                           unsigned long highmem_len)
  50 {
  51         struct page *page;
  52         unsigned long highmem_pfn;
  53         int i;
  54
  55         highmem_pfn = __pa(highmem_start) >> PAGE_SHIFT;
  56         for(i = 0; i < highmem_len >> PAGE_SHIFT; i++){
  57                 page = &mem_map[highmem_pfn + i];
  58                 ClearPageReserved(page);
  59                 init_page_count(page);
  60                 __free_page(page);
  61         }
  62 }
  63 #endif
  64
  65 void mem_init(void)
  66 {
  67         /* clear the zero-page */
  68         memset((void *) empty_zero_page, 0, PAGE_SIZE);
  69
  70         /* Map in the area just after the brk now that kmalloc is about
  71          * to be turned on.
  72          */
  73         brk_end = (unsigned long) UML_ROUND_UP(sbrk(0));
  74         map_cb(NULL);
  75         initial_thread_cb(map_cb, NULL);
  76         free_bootmem(__pa(brk_end), uml_reserved - brk_end);
  77         uml_reserved = brk_end;
  78
  79         /* this will put all low memory onto the freelists */
  80         totalram_pages = free_all_bootmem();
  81         max_low_pfn = totalram_pages;
  82 #ifdef CONFIG_HIGHMEM
  83         totalhigh_pages = highmem >> PAGE_SHIFT;
  84         totalram_pages += totalhigh_pages;
  85 #endif
  86         num_physpages = totalram_pages;
  87         max_pfn = totalram_pages;
  88         printk(KERN_INFO "Memory: %luk available\n",
  89                (unsigned long) nr_free_pages() << (PAGE_SHIFT-10));
  90         kmalloc_ok = 1;
  91
  92 #ifdef CONFIG_HIGHMEM
  93         setup_highmem(end_iomem, highmem);
  94 #endif
  95 }
  96
  97 /*
  98  * Create a page table and place a pointer to it in a middle page
  99  * directory entry.
 100  */
 101 static void __init one_page_table_init(pmd_t *pmd)
 102 {
 103         if (pmd_none(*pmd)) {
 104                 pte_t *pte = (pte_t *) alloc_bootmem_low_pages(PAGE_SIZE);
 105                 set_pmd(pmd, __pmd(_KERNPG_TABLE +
 106                                            (unsigned long) __pa(pte)));
 107                 if (pte != pte_offset_kernel(pmd, 0))
 108                         BUG();
 109         }
 110 }
 111
 112 static void __init one_md_table_init(pud_t *pud)
 113 {
 114 #ifdef CONFIG_3_LEVEL_PGTABLES
 115         pmd_t *pmd_table = (pmd_t *) alloc_bootmem_low_pages(PAGE_SIZE);
 116         set_pud(pud, __pud(_KERNPG_TABLE + (unsigned long) __pa(pmd_table)));
 117         if (pmd_table != pmd_offset(pud, 0))
 118                 BUG();
 119 #endif
 120 }
 121
 122 static void __init fixrange_init(unsigned long start, unsigned long end,
 123                                  pgd_t *pgd_base)
 124 {
 125         pgd_t *pgd;
 126         pud_t *pud;
 127         pmd_t *pmd;
 128         int i, j;
 129         unsigned long vaddr;
 130
 131         vaddr = start;
 132         i = pgd_index(vaddr);
 133         j = pmd_index(vaddr);
 134         pgd = pgd_base + i;
 135
 136         for ( ; (i < PTRS_PER_PGD) && (vaddr < end); pgd++, i++) {
 137                 pud = pud_offset(pgd, vaddr);
 138                 if (pud_none(*pud))
 139                         one_md_table_init(pud);
 140                 pmd = pmd_offset(pud, vaddr);
 141                 for (; (j < PTRS_PER_PMD) && (vaddr != end); pmd++, j++) {
 142                         one_page_table_init(pmd);
 143                         vaddr += PMD_SIZE;
 144                 }
 145                 j = 0;
 146         }
 147 }
 148
 149 #ifdef CONFIG_HIGHMEM
 150 pte_t *kmap_pte;
 151 pgprot_t kmap_prot;
 152
 153 #define kmap_get_fixmap_pte(vaddr)                                      \
 154         pte_offset_kernel(pmd_offset(pud_offset(pgd_offset_k(vaddr), (vaddr)),\
 155                           (vaddr)), (vaddr))
 156
 157 static void __init kmap_init(void)
 158 {
 159         unsigned long kmap_vstart;
 160
 161         /* cache the first kmap pte */
 162         kmap_vstart = __fix_to_virt(FIX_KMAP_BEGIN);
 163         kmap_pte = kmap_get_fixmap_pte(kmap_vstart);
 164
 165         kmap_prot = PAGE_KERNEL;
 166 }
 167
 168 static void init_highmem(void)
 169 {
 170         pgd_t *pgd;
 171         pud_t *pud;
 172         pmd_t *pmd;
 173         pte_t *pte;
 174         unsigned long vaddr;
 175
 176         /*
 177          * Permanent kmaps:
 178          */
 179         vaddr = PKMAP_BASE;
 180         fixrange_init(vaddr, vaddr + PAGE_SIZE*LAST_PKMAP, swapper_pg_dir);
 181
 182         pgd = swapper_pg_dir + pgd_index(vaddr);
 183         pud = pud_offset(pgd, vaddr);
 184         pmd = pmd_offset(pud, vaddr);
 185         pte = pte_offset_kernel(pmd, vaddr);
 186         pkmap_page_table = pte;
 187
 188         kmap_init();
 189 }
 190 #endif /* CONFIG_HIGHMEM */
 191
 192 static void __init fixaddr_user_init( void)
 193 {
 194 #ifdef CONFIG_ARCH_REUSE_HOST_VSYSCALL_AREA
 195         long size = FIXADDR_USER_END - FIXADDR_USER_START;
 196         pgd_t *pgd;
 197         pud_t *pud;
 198         pmd_t *pmd;
 199         pte_t *pte;
 200         unsigned long paddr, vaddr = FIXADDR_USER_START;
 201
 202         if (  ! size )
 203                 return;
 204
 205         fixrange_init( FIXADDR_USER_START, FIXADDR_USER_END, swapper_pg_dir);
 206         paddr = (unsigned long)alloc_bootmem_low_pages( size);
 207         memcpy( (void *)paddr, (void *)FIXADDR_USER_START, size);
 208         paddr = __pa(paddr);
 209         for ( ; size > 0; size-=PAGE_SIZE, vaddr+=PAGE_SIZE, paddr+=PAGE_SIZE){
 210                 pgd = swapper_pg_dir + pgd_index(vaddr);
 211                 pud = pud_offset(pgd, vaddr);
 212                 pmd = pmd_offset(pud, vaddr);
 213                 pte = pte_offset_kernel(pmd, vaddr);
 214                 pte_set_val( (*pte), paddr, PAGE_READONLY);
 215         }
 216 #endif
 217 }
 218
 219 void __init paging_init(void)
 220 {
 221         unsigned long zones_size[MAX_NR_ZONES], vaddr;
 222         int i;
 223
 224         empty_zero_page = (unsigned long *) alloc_bootmem_low_pages(PAGE_SIZE);
 225         empty_bad_page = (unsigned long *) alloc_bootmem_low_pages(PAGE_SIZE);
 226         for(i = 0; i < ARRAY_SIZE(zones_size); i++)
 227                 zones_size[i] = 0;
 228
 229         zones_size[ZONE_NORMAL] = (end_iomem >> PAGE_SHIFT) -
 230                 (uml_physmem >> PAGE_SHIFT);
 231 #ifdef CONFIG_HIGHMEM
 232         zones_size[ZONE_HIGHMEM] = highmem >> PAGE_SHIFT;
 233 #endif
 234         free_area_init(zones_size);
 235
 236         /*
 237          * Fixed mappings, only the page table structure has to be
 238          * created - mappings will be set by set_fixmap():
 239          */
 240         vaddr = __fix_to_virt(__end_of_fixed_addresses - 1) & PMD_MASK;
 241         fixrange_init(vaddr, FIXADDR_TOP, swapper_pg_dir);
 242
 243         fixaddr_user_init();
 244
 245 #ifdef CONFIG_HIGHMEM
 246         init_highmem();
 247 #endif
 248 }
 249
 250 struct page *arch_validate(struct page *page, gfp_t mask, int order)
 251 {
 252         unsigned long addr, zero = 0;
 253         int i;
 254
 255  again:
 256         if(page == NULL)
 257                 return page;
 258         if(PageHighMem(page))
 259                 return page;
 260
 261         addr = (unsigned long) page_address(page);
 262         for(i = 0; i < (1 << order); i++){
 263                 current->thread.fault_addr = (void *) addr;
 264                 if(__do_copy_to_user((void __user *) addr, &zero,
 265                                      sizeof(zero),
 266                                      &current->thread.fault_addr,
 267                                      &current->thread.fault_catcher)){
 268                         if(!(mask & __GFP_WAIT))
 269                                 return NULL;
 270                         else break;
 271                 }
 272                 addr += PAGE_SIZE;
 273         }
 274
 275         if(i == (1 << order))
 276                 return page;
 277         page = alloc_pages(mask, order);
 278         goto again;
 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 ("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("Mem-info:\n");
 312         show_free_areas();
 313         printk("Free swap:       %6ldkB\n", nr_swap_pages<<(PAGE_SHIFT-10));
 314         pfn = max_mapnr;
 315         while(pfn-- > 0) {
 316                 page = pfn_to_page(pfn);
 317                 total++;
 318                 if(PageHighMem(page))
 319                         highmem++;
 320                 if(PageReserved(page))
 321                         reserved++;
 322                 else if(PageSwapCache(page))
 323                         cached++;
 324                 else if(page_count(page))
 325                         shared += page_count(page) - 1;
 326         }
 327         printk("%d pages of RAM\n", total);
 328         printk("%d pages of HIGHMEM\n", highmem);
 329         printk("%d reserved pages\n", reserved);
 330         printk("%d pages shared\n", shared);
 331         printk("%d pages swap cached\n", cached);
 332 }
 333
 334 /*
 335  * Allocate and free page tables.
 336  */
 337
 338 pgd_t *pgd_alloc(struct mm_struct *mm)
 339 {
 340         pgd_t *pgd = (pgd_t *)__get_free_page(GFP_KERNEL);
 341
 342         if (pgd) {
 343                 memset(pgd, 0, USER_PTRS_PER_PGD * sizeof(pgd_t));
 344                 memcpy(pgd + USER_PTRS_PER_PGD,
 345                        swapper_pg_dir + USER_PTRS_PER_PGD,
 346                        (PTRS_PER_PGD - USER_PTRS_PER_PGD) * sizeof(pgd_t));
 347         }
 348         return pgd;
 349 }
 350
 351 void pgd_free(pgd_t *pgd)
 352 {
 353         free_page((unsigned long) pgd);
 354 }
 355
 356 pte_t *pte_alloc_one_kernel(struct mm_struct *mm, unsigned long address)
 357 {
 358         pte_t *pte;
 359
 360         pte = (pte_t *)__get_free_page(GFP_KERNEL|__GFP_REPEAT|__GFP_ZERO);
 361         return pte;
 362 }
 363
 364 struct page *pte_alloc_one(struct mm_struct *mm, unsigned long address)
 365 {
 366         struct page *pte;
 367
 368         pte = alloc_page(GFP_KERNEL|__GFP_REPEAT|__GFP_ZERO);
 369         return pte;
 370 }