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