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
  23 extern char __binary_start;
  24
  25 /* Changed during early boot */
  26 unsigned long *empty_zero_page = NULL;
  27 unsigned long *empty_bad_page = NULL;
  28 pgd_t swapper_pg_dir[PTRS_PER_PGD];
  29 unsigned long highmem;
  30 int kmalloc_ok = 0;
  31
  32 static unsigned long brk_end;
  33
  34 void unmap_physmem(void)
  35 {
  36         os_unmap_memory((void *) brk_end, uml_reserved - brk_end);
  37 }
  38
  39 static void map_cb(void *unused)
  40 {
  41         map_memory(brk_end, __pa(brk_end), uml_reserved - brk_end, 1, 1, 0);
  42 }
  43
  44 #ifdef CONFIG_HIGHMEM
  45 static void setup_highmem(unsigned long highmem_start,
  46                           unsigned long highmem_len)
  47 {
  48         struct page *page;
  49         unsigned long highmem_pfn;
  50         int i;
  51
  52         highmem_pfn = __pa(highmem_start) >> PAGE_SHIFT;
  53         for(i = 0; i < highmem_len >> PAGE_SHIFT; i++){
  54                 page = &mem_map[highmem_pfn + i];
  55                 ClearPageReserved(page);
  56                 set_bit(PG_highmem, &page->flags);
  57                 set_page_count(page, 1);
  58                 __free_page(page);
  59         }
  60 }
  61 #endif
  62
  63 void mem_init(void)
  64 {
  65         unsigned long start;
  66
  67         max_low_pfn = (high_physmem - uml_physmem) >> PAGE_SHIFT;
  68
  69         /* clear the zero-page */
  70         memset((void *) empty_zero_page, 0, PAGE_SIZE);
  71
  72         /* Map in the area just after the brk now that kmalloc is about
  73          * to be turned on.
  74          */
  75         brk_end = (unsigned long) UML_ROUND_UP(sbrk(0));
  76         map_cb(NULL);
  77         initial_thread_cb(map_cb, NULL);
  78         free_bootmem(__pa(brk_end), uml_reserved - brk_end);
  79         uml_reserved = brk_end;
  80
  81         /* Fill in any hole at the start of the binary */
  82         start = (unsigned long) &__binary_start & PAGE_MASK;
  83         if(uml_physmem != start){
  84                 map_memory(uml_physmem, __pa(uml_physmem), start - uml_physmem,
  85                            1, 1, 0);
  86         }
  87
  88         /* this will put all low memory onto the freelists */
  89         totalram_pages = free_all_bootmem();
  90         totalhigh_pages = highmem >> PAGE_SHIFT;
  91         totalram_pages += totalhigh_pages;
  92         num_physpages = totalram_pages;
  93         max_pfn = totalram_pages;
  94         printk(KERN_INFO "Memory: %luk available\n",
  95                (unsigned long) nr_free_pages() << (PAGE_SHIFT-10));
  96         kmalloc_ok = 1;
  97
  98 #ifdef CONFIG_HIGHMEM
  99         setup_highmem(end_iomem, highmem);
 100 #endif
 101 }
 102
 103 /*
 104  * Create a page table and place a pointer to it in a middle page
 105  * directory entry.
 106  */
 107 static void __init one_page_table_init(pmd_t *pmd)
 108 {
 109         if (pmd_none(*pmd)) {
 110                 pte_t *pte = (pte_t *) alloc_bootmem_low_pages(PAGE_SIZE);
 111                 set_pmd(pmd, __pmd(_KERNPG_TABLE +
 112                                            (unsigned long) __pa(pte)));
 113                 if (pte != pte_offset_kernel(pmd, 0))
 114                         BUG();
 115         }
 116 }
 117
 118 static void __init one_md_table_init(pud_t *pud)
 119 {
 120 #ifdef CONFIG_3_LEVEL_PGTABLES
 121         pmd_t *pmd_table = (pmd_t *) alloc_bootmem_low_pages(PAGE_SIZE);
 122         set_pud(pud, __pud(_KERNPG_TABLE + (unsigned long) __pa(pmd_table)));
 123         if (pmd_table != pmd_offset(pud, 0))
 124                 BUG();
 125 #endif
 126 }
 127
 128 static void __init fixrange_init(unsigned long start, unsigned long end,
 129                                  pgd_t *pgd_base)
 130 {
 131         pgd_t *pgd;
 132         pud_t *pud;
 133         pmd_t *pmd;
 134         int i, j;
 135         unsigned long vaddr;
 136
 137         vaddr = start;
 138         i = pgd_index(vaddr);
 139         j = pmd_index(vaddr);
 140         pgd = pgd_base + i;
 141
 142         for ( ; (i < PTRS_PER_PGD) && (vaddr < end); pgd++, i++) {
 143                 pud = pud_offset(pgd, vaddr);
 144                 if (pud_none(*pud))
 145                         one_md_table_init(pud);
 146                 pmd = pmd_offset(pud, vaddr);
 147                 for (; (j < PTRS_PER_PMD) && (vaddr != end); pmd++, j++) {
 148                         one_page_table_init(pmd);
 149                         vaddr += PMD_SIZE;
 150                 }
 151                 j = 0;
 152         }
 153 }
 154
 155 #ifdef CONFIG_HIGHMEM
 156 pte_t *kmap_pte;
 157 pgprot_t kmap_prot;
 158
 159 #define kmap_get_fixmap_pte(vaddr)                                      \
 160         pte_offset_kernel(pmd_offset(pud_offset(pgd_offset_k(vaddr), (vaddr)),\
 161                           (vaddr)), (vaddr))
 162
 163 static void __init kmap_init(void)
 164 {
 165         unsigned long kmap_vstart;
 166
 167         /* cache the first kmap pte */
 168         kmap_vstart = __fix_to_virt(FIX_KMAP_BEGIN);
 169         kmap_pte = kmap_get_fixmap_pte(kmap_vstart);
 170
 171         kmap_prot = PAGE_KERNEL;
 172 }
 173
 174 static void init_highmem(void)
 175 {
 176         pgd_t *pgd;
 177         pud_t *pud;
 178         pmd_t *pmd;
 179         pte_t *pte;
 180         unsigned long vaddr;
 181
 182         /*
 183          * Permanent kmaps:
 184          */
 185         vaddr = PKMAP_BASE;
 186         fixrange_init(vaddr, vaddr + PAGE_SIZE*LAST_PKMAP, swapper_pg_dir);
 187
 188         pgd = swapper_pg_dir + pgd_index(vaddr);
 189         pud = pud_offset(pgd, vaddr);
 190         pmd = pmd_offset(pud, vaddr);
 191         pte = pte_offset_kernel(pmd, vaddr);
 192         pkmap_page_table = pte;
 193
 194         kmap_init();
 195 }
 196 #endif /* CONFIG_HIGHMEM */
 197
 198 static void __init fixaddr_user_init( void)
 199 {
 200 #if CONFIG_ARCH_REUSE_HOST_VSYSCALL_AREA
 201         long size = FIXADDR_USER_END - FIXADDR_USER_START;
 202         pgd_t *pgd;
 203         pud_t *pud;
 204         pmd_t *pmd;
 205         pte_t *pte;
 206         unsigned long paddr, vaddr = FIXADDR_USER_START;
 207
 208         if (  ! size )
 209                 return;
 210
 211         fixrange_init( FIXADDR_USER_START, FIXADDR_USER_END, swapper_pg_dir);
 212         paddr = (unsigned long)alloc_bootmem_low_pages( size);
 213         memcpy( (void *)paddr, (void *)FIXADDR_USER_START, size);
 214         paddr = __pa(paddr);
 215         for ( ; size > 0; size-=PAGE_SIZE, vaddr+=PAGE_SIZE, paddr+=PAGE_SIZE){
 216                 pgd = swapper_pg_dir + pgd_index(vaddr);
 217                 pud = pud_offset(pgd, vaddr);
 218                 pmd = pmd_offset(pud, vaddr);
 219                 pte = pte_offset_kernel(pmd, vaddr);
 220                 pte_set_val( (*pte), paddr, PAGE_READONLY);
 221         }
 222 #endif
 223 }
 224
 225 void paging_init(void)
 226 {
 227         unsigned long zones_size[MAX_NR_ZONES], vaddr;
 228         int i;
 229
 230         empty_zero_page = (unsigned long *) alloc_bootmem_low_pages(PAGE_SIZE);
 231         empty_bad_page = (unsigned long *) alloc_bootmem_low_pages(PAGE_SIZE);
 232         for(i=0;i<sizeof(zones_size)/sizeof(zones_size[0]);i++)
 233                 zones_size[i] = 0;
 234         zones_size[0] = (end_iomem >> PAGE_SHIFT) - (uml_physmem >> PAGE_SHIFT);
 235         zones_size[2] = highmem >> PAGE_SHIFT;
 236         free_area_init(zones_size);
 237
 238         /*
 239          * Fixed mappings, only the page table structure has to be
 240          * created - mappings will be set by set_fixmap():
 241          */
 242         vaddr = __fix_to_virt(__end_of_fixed_addresses - 1) & PMD_MASK;
 243         fixrange_init(vaddr, FIXADDR_TOP, swapper_pg_dir);
 244
 245         fixaddr_user_init();
 246
 247 #ifdef CONFIG_HIGHMEM
 248         init_highmem();
 249 #endif
 250 }
 251
 252 struct page *arch_validate(struct page *page, int mask, int order)
 253 {
 254         unsigned long addr, zero = 0;
 255         int i;
 256
 257  again:
 258         if(page == NULL) return(page);
 259         if(PageHighMem(page)) 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)) return(NULL);
 269                         else break;
 270                 }
 271                 addr += PAGE_SIZE;
 272         }
 273
 274         if(i == (1 << order)) return(page);
 275         page = alloc_pages(mask, order);
 276         goto again;
 277 }
 278
 279 /* This can't do anything because nothing in the kernel image can be freed
 280  * since it's not in kernel physical memory.
 281  */
 282
 283 void free_initmem(void)
 284 {
 285 }
 286
 287 #ifdef CONFIG_BLK_DEV_INITRD
 288
 289 void free_initrd_mem(unsigned long start, unsigned long end)
 290 {
 291         if (start < end)
 292                 printk ("Freeing initrd memory: %ldk freed\n",
 293                         (end - start) >> 10);
 294         for (; start < end; start += PAGE_SIZE) {
 295                 ClearPageReserved(virt_to_page(start));
 296                 set_page_count(virt_to_page(start), 1);
 297                 free_page(start);
 298                 totalram_pages++;
 299         }
 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 }
 371
 372 /*
 373  * Overrides for Emacs so that we follow Linus's tabbing style.
 374  * Emacs will notice this stuff at the end of the file and automatically
 375  * adjust the settings for this buffer only.  This must remain at the end
 376  * of the file.
 377  * ---------------------------------------------------------------------------
 378  * Local variables:
 379  * c-file-style: "linux"
 380  * End:
 381  */