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 extern char __binary_start;
  28
  29 /* Changed during early boot */
  30 unsigned long *empty_zero_page = NULL;
  31 unsigned long *empty_bad_page = NULL;
  32 pgd_t swapper_pg_dir[PTRS_PER_PGD];
  33 unsigned long highmem;
  34 int kmalloc_ok = 0;
  35
  36 static unsigned long brk_end;
  37
  38 void unmap_physmem(void)
  39 {
  40         os_unmap_memory((void *) brk_end, uml_reserved - brk_end);
  41 }
  42
  43 static void map_cb(void *unused)
  44 {
  45         map_memory(brk_end, __pa(brk_end), uml_reserved - brk_end, 1, 1, 0);
  46 }
  47
  48 #ifdef CONFIG_HIGHMEM
  49 static void setup_highmem(unsigned long highmem_start,
  50                           unsigned long highmem_len)
  51 {
  52         struct page *page;
  53         unsigned long highmem_pfn;
  54         int i;
  55
  56         highmem_pfn = __pa(highmem_start) >> PAGE_SHIFT;
  57         for(i = 0; i < highmem_len >> PAGE_SHIFT; i++){
  58                 page = &mem_map[highmem_pfn + i];
  59                 ClearPageReserved(page);
  60                 set_page_count(page, 1);
  61                 __free_page(page);
  62         }
  63 }
  64 #endif
  65
  66 void mem_init(void)
  67 {
  68         unsigned long start;
  69
  70         max_low_pfn = (high_physmem - uml_physmem) >> PAGE_SHIFT;
  71
  72         /* clear the zero-page */
  73         memset((void *) empty_zero_page, 0, PAGE_SIZE);
  74
  75         /* Map in the area just after the brk now that kmalloc is about
  76          * to be turned on.
  77          */
  78         brk_end = (unsigned long) UML_ROUND_UP(sbrk(0));
  79         map_cb(NULL);
  80         initial_thread_cb(map_cb, NULL);
  81         free_bootmem(__pa(brk_end), uml_reserved - brk_end);
  82         uml_reserved = brk_end;
  83
  84         /* Fill in any hole at the start of the binary */
  85         start = (unsigned long) &__binary_start & PAGE_MASK;
  86         if(uml_physmem != start){
  87                 map_memory(uml_physmem, __pa(uml_physmem), start - uml_physmem,
  88                            1, 1, 0);
  89         }
  90
  91         /* this will put all low memory onto the freelists */
  92         totalram_pages = free_all_bootmem();
  93         totalhigh_pages = highmem >> PAGE_SHIFT;
  94         totalram_pages += totalhigh_pages;
  95         num_physpages = totalram_pages;
  96         max_pfn = totalram_pages;
  97         printk(KERN_INFO "Memory: %luk available\n",
  98                (unsigned long) nr_free_pages() << (PAGE_SHIFT-10));
  99         kmalloc_ok = 1;
 100
 101 #ifdef CONFIG_HIGHMEM
 102         setup_highmem(end_iomem, highmem);
 103 #endif
 104 }
 105
 106 /*
 107  * Create a page table and place a pointer to it in a middle page
 108  * directory entry.
 109  */
 110 static void __init one_page_table_init(pmd_t *pmd)
 111 {
 112         if (pmd_none(*pmd)) {
 113                 pte_t *pte = (pte_t *) alloc_bootmem_low_pages(PAGE_SIZE);
 114                 set_pmd(pmd, __pmd(_KERNPG_TABLE +
 115                                            (unsigned long) __pa(pte)));
 116                 if (pte != pte_offset_kernel(pmd, 0))
 117                         BUG();
 118         }
 119 }
 120
 121 static void __init one_md_table_init(pud_t *pud)
 122 {
 123 #ifdef CONFIG_3_LEVEL_PGTABLES
 124         pmd_t *pmd_table = (pmd_t *) alloc_bootmem_low_pages(PAGE_SIZE);
 125         set_pud(pud, __pud(_KERNPG_TABLE + (unsigned long) __pa(pmd_table)));
 126         if (pmd_table != pmd_offset(pud, 0))
 127                 BUG();
 128 #endif
 129 }
 130
 131 static void __init fixrange_init(unsigned long start, unsigned long end,
 132                                  pgd_t *pgd_base)
 133 {
 134         pgd_t *pgd;
 135         pud_t *pud;
 136         pmd_t *pmd;
 137         int i, j;
 138         unsigned long vaddr;
 139
 140         vaddr = start;
 141         i = pgd_index(vaddr);
 142         j = pmd_index(vaddr);
 143         pgd = pgd_base + i;
 144
 145         for ( ; (i < PTRS_PER_PGD) && (vaddr < end); pgd++, i++) {
 146                 pud = pud_offset(pgd, vaddr);
 147                 if (pud_none(*pud))
 148                         one_md_table_init(pud);
 149                 pmd = pmd_offset(pud, vaddr);
 150                 for (; (j < PTRS_PER_PMD) && (vaddr != end); pmd++, j++) {
 151                         one_page_table_init(pmd);
 152                         vaddr += PMD_SIZE;
 153                 }
 154                 j = 0;
 155         }
 156 }
 157
 158 #ifdef CONFIG_HIGHMEM
 159 pte_t *kmap_pte;
 160 pgprot_t kmap_prot;
 161
 162 #define kmap_get_fixmap_pte(vaddr)                                      \
 163         pte_offset_kernel(pmd_offset(pud_offset(pgd_offset_k(vaddr), (vaddr)),\
 164                           (vaddr)), (vaddr))
 165
 166 static void __init kmap_init(void)
 167 {
 168         unsigned long kmap_vstart;
 169
 170         /* cache the first kmap pte */
 171         kmap_vstart = __fix_to_virt(FIX_KMAP_BEGIN);
 172         kmap_pte = kmap_get_fixmap_pte(kmap_vstart);
 173
 174         kmap_prot = PAGE_KERNEL;
 175 }
 176
 177 static void init_highmem(void)
 178 {
 179         pgd_t *pgd;
 180         pud_t *pud;
 181         pmd_t *pmd;
 182         pte_t *pte;
 183         unsigned long vaddr;
 184
 185         /*
 186          * Permanent kmaps:
 187          */
 188         vaddr = PKMAP_BASE;
 189         fixrange_init(vaddr, vaddr + PAGE_SIZE*LAST_PKMAP, swapper_pg_dir);
 190
 191         pgd = swapper_pg_dir + pgd_index(vaddr);
 192         pud = pud_offset(pgd, vaddr);
 193         pmd = pmd_offset(pud, vaddr);
 194         pte = pte_offset_kernel(pmd, vaddr);
 195         pkmap_page_table = pte;
 196
 197         kmap_init();
 198 }
 199 #endif /* CONFIG_HIGHMEM */
 200
 201 static void __init fixaddr_user_init( void)
 202 {
 203 #ifdef CONFIG_ARCH_REUSE_HOST_VSYSCALL_AREA
 204         long size = FIXADDR_USER_END - FIXADDR_USER_START;
 205         pgd_t *pgd;
 206         pud_t *pud;
 207         pmd_t *pmd;
 208         pte_t *pte;
 209         unsigned long paddr, vaddr = FIXADDR_USER_START;
 210
 211         if (  ! size )
 212                 return;
 213
 214         fixrange_init( FIXADDR_USER_START, FIXADDR_USER_END, swapper_pg_dir);
 215         paddr = (unsigned long)alloc_bootmem_low_pages( size);
 216         memcpy( (void *)paddr, (void *)FIXADDR_USER_START, size);
 217         paddr = __pa(paddr);
 218         for ( ; size > 0; size-=PAGE_SIZE, vaddr+=PAGE_SIZE, paddr+=PAGE_SIZE){
 219                 pgd = swapper_pg_dir + pgd_index(vaddr);
 220                 pud = pud_offset(pgd, vaddr);
 221                 pmd = pmd_offset(pud, vaddr);
 222                 pte = pte_offset_kernel(pmd, vaddr);
 223                 pte_set_val( (*pte), paddr, PAGE_READONLY);
 224         }
 225 #endif
 226 }
 227
 228 void paging_init(void)
 229 {
 230         unsigned long zones_size[MAX_NR_ZONES], vaddr;
 231         int i;
 232
 233         empty_zero_page = (unsigned long *) alloc_bootmem_low_pages(PAGE_SIZE);
 234         empty_bad_page = (unsigned long *) alloc_bootmem_low_pages(PAGE_SIZE);
 235         for(i=0;i<sizeof(zones_size)/sizeof(zones_size[0]);i++)
 236                 zones_size[i] = 0;
 237         zones_size[ZONE_DMA] = (end_iomem >> PAGE_SHIFT) - (uml_physmem >> PAGE_SHIFT);
 238         zones_size[ZONE_HIGHMEM] = highmem >> PAGE_SHIFT;
 239         free_area_init(zones_size);
 240
 241         /*
 242          * Fixed mappings, only the page table structure has to be
 243          * created - mappings will be set by set_fixmap():
 244          */
 245         vaddr = __fix_to_virt(__end_of_fixed_addresses - 1) & PMD_MASK;
 246         fixrange_init(vaddr, FIXADDR_TOP, swapper_pg_dir);
 247
 248         fixaddr_user_init();
 249
 250 #ifdef CONFIG_HIGHMEM
 251         init_highmem();
 252 #endif
 253 }
 254
 255 struct page *arch_validate(struct page *page, gfp_t mask, int order)
 256 {
 257         unsigned long addr, zero = 0;
 258         int i;
 259
 260  again:
 261         if(page == NULL) return(page);
 262         if(PageHighMem(page)) return(page);
 263
 264         addr = (unsigned long) page_address(page);
 265         for(i = 0; i < (1 << order); i++){
 266                 current->thread.fault_addr = (void *) addr;
 267                 if(__do_copy_to_user((void __user *) addr, &zero,
 268                                      sizeof(zero),
 269                                      &current->thread.fault_addr,
 270                                      &current->thread.fault_catcher)){
 271                         if(!(mask & __GFP_WAIT)) return(NULL);
 272                         else break;
 273                 }
 274                 addr += PAGE_SIZE;
 275         }
 276
 277         if(i == (1 << order)) return(page);
 278         page = alloc_pages(mask, order);
 279         goto again;
 280 }
 281
 282 /* This can't do anything because nothing in the kernel image can be freed
 283  * since it's not in kernel physical memory.
 284  */
 285
 286 void free_initmem(void)
 287 {
 288 }
 289
 290 #ifdef CONFIG_BLK_DEV_INITRD
 291
 292 void free_initrd_mem(unsigned long start, unsigned long end)
 293 {
 294         if (start < end)
 295                 printk ("Freeing initrd memory: %ldk freed\n",
 296                         (end - start) >> 10);
 297         for (; start < end; start += PAGE_SIZE) {
 298                 ClearPageReserved(virt_to_page(start));
 299                 set_page_count(virt_to_page(start), 1);
 300                 free_page(start);
 301                 totalram_pages++;
 302         }
 303 }
 304
 305 #endif
 306
 307 void show_mem(void)
 308 {
 309         int pfn, total = 0, reserved = 0;
 310         int shared = 0, cached = 0;
 311         int highmem = 0;
 312         struct page *page;
 313
 314         printk("Mem-info:\n");
 315         show_free_areas();
 316         printk("Free swap:       %6ldkB\n", nr_swap_pages<<(PAGE_SHIFT-10));
 317         pfn = max_mapnr;
 318         while(pfn-- > 0) {
 319                 page = pfn_to_page(pfn);
 320                 total++;
 321                 if(PageHighMem(page))
 322                         highmem++;
 323                 if(PageReserved(page))
 324                         reserved++;
 325                 else if(PageSwapCache(page))
 326                         cached++;
 327                 else if(page_count(page))
 328                         shared += page_count(page) - 1;
 329         }
 330         printk("%d pages of RAM\n", total);
 331         printk("%d pages of HIGHMEM\n", highmem);
 332         printk("%d reserved pages\n", reserved);
 333         printk("%d pages shared\n", shared);
 334         printk("%d pages swap cached\n", cached);
 335 }
 336
 337 /*
 338  * Allocate and free page tables.
 339  */
 340
 341 pgd_t *pgd_alloc(struct mm_struct *mm)
 342 {
 343         pgd_t *pgd = (pgd_t *)__get_free_page(GFP_KERNEL);
 344
 345         if (pgd) {
 346                 memset(pgd, 0, USER_PTRS_PER_PGD * sizeof(pgd_t));
 347                 memcpy(pgd + USER_PTRS_PER_PGD,
 348                        swapper_pg_dir + USER_PTRS_PER_PGD,
 349                        (PTRS_PER_PGD - USER_PTRS_PER_PGD) * sizeof(pgd_t));
 350         }
 351         return pgd;
 352 }
 353
 354 void pgd_free(pgd_t *pgd)
 355 {
 356         free_page((unsigned long) pgd);
 357 }
 358
 359 pte_t *pte_alloc_one_kernel(struct mm_struct *mm, unsigned long address)
 360 {
 361         pte_t *pte;
 362
 363         pte = (pte_t *)__get_free_page(GFP_KERNEL|__GFP_REPEAT|__GFP_ZERO);
 364         return pte;
 365 }
 366
 367 struct page *pte_alloc_one(struct mm_struct *mm, unsigned long address)
 368 {
 369         struct page *pte;
 370
 371         pte = alloc_page(GFP_KERNEL|__GFP_REPEAT|__GFP_ZERO);
 372         return pte;
 373 }
 374
 375 struct iomem_region *iomem_regions = NULL;
 376 int iomem_size = 0;
 377
 378 extern int parse_iomem(char *str, int *add) __init;
 379
 380 __uml_setup("iomem=", parse_iomem,
 381 "iomem=<name>,<file>\n"
 382 "    Configure <file> as an IO memory region named <name>.\n\n"
 383 );
 384
 385 /*
 386  * Overrides for Emacs so that we follow Linus's tabbing style.
 387  * Emacs will notice this stuff at the end of the file and automatically
 388  * adjust the settings for this buffer only.  This must remain at the end
 389  * of the file.
 390  * ---------------------------------------------------------------------------
 391  * Local variables:
 392  * c-file-style: "linux"
 393  * End:
 394  */