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 "user_util.h"
  17 #include "kern_util.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 /* Changed during early boot */
  28 unsigned long *empty_zero_page = NULL;
  29 unsigned long *empty_bad_page = NULL;
  30 pgd_t swapper_pg_dir[PTRS_PER_PGD];
  31 unsigned long long highmem;
  32 int kmalloc_ok = 0;
  33
  34 static unsigned long brk_end;
  35
  36 void unmap_physmem(void)
  37 {
  38         os_unmap_memory((void *) brk_end, uml_reserved - brk_end);
  39 }
  40
  41 static void map_cb(void *unused)
  42 {
  43         map_memory(brk_end, __pa(brk_end), uml_reserved - brk_end, 1, 1, 0);
  44 }
  45
  46 #ifdef CONFIG_HIGHMEM
  47 static void setup_highmem(unsigned long highmem_start,
  48                           unsigned long highmem_len)
  49 {
  50         struct page *page;
  51         unsigned long highmem_pfn;
  52         int i;
  53
  54         highmem_pfn = __pa(highmem_start) >> PAGE_SHIFT;
  55         for(i = 0; i < highmem_len >> PAGE_SHIFT; i++){
  56                 page = &mem_map[highmem_pfn + i];
  57                 ClearPageReserved(page);
  58                 init_page_count(page);
  59                 __free_page(page);
  60         }
  61 }
  62 #endif
  63
  64 void mem_init(void)
  65 {
  66         max_low_pfn = (high_physmem - uml_physmem) >> PAGE_SHIFT;
  67
  68         /* clear the zero-page */
  69         memset((void *) empty_zero_page, 0, PAGE_SIZE);
  70
  71         /* Map in the area just after the brk now that kmalloc is about
  72          * to be turned on.
  73          */
  74         brk_end = (unsigned long) UML_ROUND_UP(sbrk(0));
  75         map_cb(NULL);
  76         initial_thread_cb(map_cb, NULL);
  77         free_bootmem(__pa(brk_end), uml_reserved - brk_end);
  78         uml_reserved = brk_end;
  79
  80         /* this will put all low memory onto the freelists */
  81         totalram_pages = free_all_bootmem();
  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 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) return(page);
 257         if(PageHighMem(page)) return(page);
 258
 259         addr = (unsigned long) page_address(page);
 260         for(i = 0; i < (1 << order); i++){
 261                 current->thread.fault_addr = (void *) addr;
 262                 if(__do_copy_to_user((void __user *) addr, &zero,
 263                                      sizeof(zero),
 264                                      &current->thread.fault_addr,
 265                                      &current->thread.fault_catcher)){
 266                         if(!(mask & __GFP_WAIT)) return(NULL);
 267                         else break;
 268                 }
 269                 addr += PAGE_SIZE;
 270         }
 271
 272         if(i == (1 << order)) return(page);
 273         page = alloc_pages(mask, order);
 274         goto again;
 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
 287 void free_initrd_mem(unsigned long start, unsigned long end)
 288 {
 289         if (start < end)
 290                 printk ("Freeing initrd memory: %ldk freed\n",
 291                         (end - start) >> 10);
 292         for (; start < end; start += PAGE_SIZE) {
 293                 ClearPageReserved(virt_to_page(start));
 294                 init_page_count(virt_to_page(start));
 295                 free_page(start);
 296                 totalram_pages++;
 297         }
 298 }
 299
 300 #endif
 301
 302 void show_mem(void)
 303 {
 304         int pfn, total = 0, reserved = 0;
 305         int shared = 0, cached = 0;
 306         int highmem = 0;
 307         struct page *page;
 308
 309         printk("Mem-info:\n");
 310         show_free_areas();
 311         printk("Free swap:       %6ldkB\n", nr_swap_pages<<(PAGE_SHIFT-10));
 312         pfn = max_mapnr;
 313         while(pfn-- > 0) {
 314                 page = pfn_to_page(pfn);
 315                 total++;
 316                 if(PageHighMem(page))
 317                         highmem++;
 318                 if(PageReserved(page))
 319                         reserved++;
 320                 else if(PageSwapCache(page))
 321                         cached++;
 322                 else if(page_count(page))
 323                         shared += page_count(page) - 1;
 324         }
 325         printk("%d pages of RAM\n", total);
 326         printk("%d pages of HIGHMEM\n", highmem);
 327         printk("%d reserved pages\n", reserved);
 328         printk("%d pages shared\n", shared);
 329         printk("%d pages swap cached\n", cached);
 330 }
 331
 332 /*
 333  * Allocate and free page tables.
 334  */
 335
 336 pgd_t *pgd_alloc(struct mm_struct *mm)
 337 {
 338         pgd_t *pgd = (pgd_t *)__get_free_page(GFP_KERNEL);
 339
 340         if (pgd) {
 341                 memset(pgd, 0, USER_PTRS_PER_PGD * sizeof(pgd_t));
 342                 memcpy(pgd + USER_PTRS_PER_PGD,
 343                        swapper_pg_dir + USER_PTRS_PER_PGD,
 344                        (PTRS_PER_PGD - USER_PTRS_PER_PGD) * sizeof(pgd_t));
 345         }
 346         return pgd;
 347 }
 348
 349 void pgd_free(pgd_t *pgd)
 350 {
 351         free_page((unsigned long) pgd);
 352 }
 353
 354 pte_t *pte_alloc_one_kernel(struct mm_struct *mm, unsigned long address)
 355 {
 356         pte_t *pte;
 357
 358         pte = (pte_t *)__get_free_page(GFP_KERNEL|__GFP_REPEAT|__GFP_ZERO);
 359         return pte;
 360 }
 361
 362 struct page *pte_alloc_one(struct mm_struct *mm, unsigned long address)
 363 {
 364         struct page *pte;
 365
 366         pte = alloc_page(GFP_KERNEL|__GFP_REPEAT|__GFP_ZERO);
 367         return pte;
 368 }
 369
 370 struct iomem_region *iomem_regions = NULL;
 371 int iomem_size = 0;
 372
 373 extern int parse_iomem(char *str, int *add) __init;
 374
 375 __uml_setup("iomem=", parse_iomem,
 376 "iomem=<name>,<file>\n"
 377 "    Configure <file> as an IO memory region named <name>.\n\n"
 378 );
 379
 380 /*
 381  * Overrides for Emacs so that we follow Linus's tabbing style.
 382  * Emacs will notice this stuff at the end of the file and automatically
 383  * adjust the settings for this buffer only.  This must remain at the end
 384  * of the file.
 385  * ---------------------------------------------------------------------------
 386  * Local variables:
 387  * c-file-style: "linux"
 388  * End:
 389  */