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_page_count(page, 1);
  57                 __free_page(page);
  58         }
  59 }
  60 #endif
  61
  62 void mem_init(void)
  63 {
  64         unsigned long start;
  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         /* Fill in any hole at the start of the binary */
  81         start = (unsigned long) &__binary_start & PAGE_MASK;
  82         if(uml_physmem != start){
  83                 map_memory(uml_physmem, __pa(uml_physmem), start - uml_physmem,
  84                            1, 1, 0);
  85         }
  86
  87         /* this will put all low memory onto the freelists */
  88         totalram_pages = free_all_bootmem();
  89         totalhigh_pages = highmem >> PAGE_SHIFT;
  90         totalram_pages += totalhigh_pages;
  91         num_physpages = totalram_pages;
  92         max_pfn = totalram_pages;
  93         printk(KERN_INFO "Memory: %luk available\n",
  94                (unsigned long) nr_free_pages() << (PAGE_SHIFT-10));
  95         kmalloc_ok = 1;
  96
  97 #ifdef CONFIG_HIGHMEM
  98         setup_highmem(end_iomem, highmem);
  99 #endif
 100 }
 101
 102 /*
 103  * Create a page table and place a pointer to it in a middle page
 104  * directory entry.
 105  */
 106 static void __init one_page_table_init(pmd_t *pmd)
 107 {
 108         if (pmd_none(*pmd)) {
 109                 pte_t *pte = (pte_t *) alloc_bootmem_low_pages(PAGE_SIZE);
 110                 set_pmd(pmd, __pmd(_KERNPG_TABLE +
 111                                            (unsigned long) __pa(pte)));
 112                 if (pte != pte_offset_kernel(pmd, 0))
 113                         BUG();
 114         }
 115 }
 116
 117 static void __init one_md_table_init(pud_t *pud)
 118 {
 119 #ifdef CONFIG_3_LEVEL_PGTABLES
 120         pmd_t *pmd_table = (pmd_t *) alloc_bootmem_low_pages(PAGE_SIZE);
 121         set_pud(pud, __pud(_KERNPG_TABLE + (unsigned long) __pa(pmd_table)));
 122         if (pmd_table != pmd_offset(pud, 0))
 123                 BUG();
 124 #endif
 125 }
 126
 127 static void __init fixrange_init(unsigned long start, unsigned long end,
 128                                  pgd_t *pgd_base)
 129 {
 130         pgd_t *pgd;
 131         pud_t *pud;
 132         pmd_t *pmd;
 133         int i, j;
 134         unsigned long vaddr;
 135
 136         vaddr = start;
 137         i = pgd_index(vaddr);
 138         j = pmd_index(vaddr);
 139         pgd = pgd_base + i;
 140
 141         for ( ; (i < PTRS_PER_PGD) && (vaddr < end); pgd++, i++) {
 142                 pud = pud_offset(pgd, vaddr);
 143                 if (pud_none(*pud))
 144                         one_md_table_init(pud);
 145                 pmd = pmd_offset(pud, vaddr);
 146                 for (; (j < PTRS_PER_PMD) && (vaddr != end); pmd++, j++) {
 147                         one_page_table_init(pmd);
 148                         vaddr += PMD_SIZE;
 149                 }
 150                 j = 0;
 151         }
 152 }
 153
 154 #ifdef CONFIG_HIGHMEM
 155 pte_t *kmap_pte;
 156 pgprot_t kmap_prot;
 157
 158 #define kmap_get_fixmap_pte(vaddr)                                      \
 159         pte_offset_kernel(pmd_offset(pud_offset(pgd_offset_k(vaddr), (vaddr)),\
 160                           (vaddr)), (vaddr))
 161
 162 static void __init kmap_init(void)
 163 {
 164         unsigned long kmap_vstart;
 165
 166         /* cache the first kmap pte */
 167         kmap_vstart = __fix_to_virt(FIX_KMAP_BEGIN);
 168         kmap_pte = kmap_get_fixmap_pte(kmap_vstart);
 169
 170         kmap_prot = PAGE_KERNEL;
 171 }
 172
 173 static void init_highmem(void)
 174 {
 175         pgd_t *pgd;
 176         pud_t *pud;
 177         pmd_t *pmd;
 178         pte_t *pte;
 179         unsigned long vaddr;
 180
 181         /*
 182          * Permanent kmaps:
 183          */
 184         vaddr = PKMAP_BASE;
 185         fixrange_init(vaddr, vaddr + PAGE_SIZE*LAST_PKMAP, swapper_pg_dir);
 186
 187         pgd = swapper_pg_dir + pgd_index(vaddr);
 188         pud = pud_offset(pgd, vaddr);
 189         pmd = pmd_offset(pud, vaddr);
 190         pte = pte_offset_kernel(pmd, vaddr);
 191         pkmap_page_table = pte;
 192
 193         kmap_init();
 194 }
 195 #endif /* CONFIG_HIGHMEM */
 196
 197 static void __init fixaddr_user_init( void)
 198 {
 199 #ifdef CONFIG_ARCH_REUSE_HOST_VSYSCALL_AREA
 200         long size = FIXADDR_USER_END - FIXADDR_USER_START;
 201         pgd_t *pgd;
 202         pud_t *pud;
 203         pmd_t *pmd;
 204         pte_t *pte;
 205         unsigned long paddr, vaddr = FIXADDR_USER_START;
 206
 207         if (  ! size )
 208                 return;
 209
 210         fixrange_init( FIXADDR_USER_START, FIXADDR_USER_END, swapper_pg_dir);
 211         paddr = (unsigned long)alloc_bootmem_low_pages( size);
 212         memcpy( (void *)paddr, (void *)FIXADDR_USER_START, size);
 213         paddr = __pa(paddr);
 214         for ( ; size > 0; size-=PAGE_SIZE, vaddr+=PAGE_SIZE, paddr+=PAGE_SIZE){
 215                 pgd = swapper_pg_dir + pgd_index(vaddr);
 216                 pud = pud_offset(pgd, vaddr);
 217                 pmd = pmd_offset(pud, vaddr);
 218                 pte = pte_offset_kernel(pmd, vaddr);
 219                 pte_set_val( (*pte), paddr, PAGE_READONLY);
 220         }
 221 #endif
 222 }
 223
 224 void paging_init(void)
 225 {
 226         unsigned long zones_size[MAX_NR_ZONES], vaddr;
 227         int i;
 228
 229         empty_zero_page = (unsigned long *) alloc_bootmem_low_pages(PAGE_SIZE);
 230         empty_bad_page = (unsigned long *) alloc_bootmem_low_pages(PAGE_SIZE);
 231         for(i=0;i<sizeof(zones_size)/sizeof(zones_size[0]);i++)
 232                 zones_size[i] = 0;
 233         zones_size[0] = (end_iomem >> PAGE_SHIFT) - (uml_physmem >> PAGE_SHIFT);
 234         zones_size[2] = highmem >> PAGE_SHIFT;
 235         free_area_init(zones_size);
 236
 237         /*
 238          * Fixed mappings, only the page table structure has to be
 239          * created - mappings will be set by set_fixmap():
 240          */
 241         vaddr = __fix_to_virt(__end_of_fixed_addresses - 1) & PMD_MASK;
 242         fixrange_init(vaddr, FIXADDR_TOP, swapper_pg_dir);
 243
 244         fixaddr_user_init();
 245
 246 #ifdef CONFIG_HIGHMEM
 247         init_highmem();
 248 #endif
 249 }
 250
 251 struct page *arch_validate(struct page *page, int mask, int order)
 252 {
 253         unsigned long addr, zero = 0;
 254         int i;
 255
 256  again:
 257         if(page == NULL) return(page);
 258         if(PageHighMem(page)) return(page);
 259
 260         addr = (unsigned long) page_address(page);
 261         for(i = 0; i < (1 << order); i++){
 262                 current->thread.fault_addr = (void *) addr;
 263                 if(__do_copy_to_user((void __user *) addr, &zero,
 264                                      sizeof(zero),
 265                                      &current->thread.fault_addr,
 266                                      &current->thread.fault_catcher)){
 267                         if(!(mask & __GFP_WAIT)) return(NULL);
 268                         else break;
 269                 }
 270                 addr += PAGE_SIZE;
 271         }
 272
 273         if(i == (1 << order)) return(page);
 274         page = alloc_pages(mask, order);
 275         goto again;
 276 }
 277
 278 /* This can't do anything because nothing in the kernel image can be freed
 279  * since it's not in kernel physical memory.
 280  */
 281
 282 void free_initmem(void)
 283 {
 284 }
 285
 286 #ifdef CONFIG_BLK_DEV_INITRD
 287
 288 void free_initrd_mem(unsigned long start, unsigned long end)
 289 {
 290         if (start < end)
 291                 printk ("Freeing initrd memory: %ldk freed\n",
 292                         (end - start) >> 10);
 293         for (; start < end; start += PAGE_SIZE) {
 294                 ClearPageReserved(virt_to_page(start));
 295                 set_page_count(virt_to_page(start), 1);
 296                 free_page(start);
 297                 totalram_pages++;
 298         }
 299 }
 300
 301 #endif
 302
 303 void show_mem(void)
 304 {
 305         int pfn, total = 0, reserved = 0;
 306         int shared = 0, cached = 0;
 307         int highmem = 0;
 308         struct page *page;
 309
 310         printk("Mem-info:\n");
 311         show_free_areas();
 312         printk("Free swap:       %6ldkB\n", nr_swap_pages<<(PAGE_SHIFT-10));
 313         pfn = max_mapnr;
 314         while(pfn-- > 0) {
 315                 page = pfn_to_page(pfn);
 316                 total++;
 317                 if(PageHighMem(page))
 318                         highmem++;
 319                 if(PageReserved(page))
 320                         reserved++;
 321                 else if(PageSwapCache(page))
 322                         cached++;
 323                 else if(page_count(page))
 324                         shared += page_count(page) - 1;
 325         }
 326         printk("%d pages of RAM\n", total);
 327         printk("%d pages of HIGHMEM\n", highmem);
 328         printk("%d reserved pages\n", reserved);
 329         printk("%d pages shared\n", shared);
 330         printk("%d pages swap cached\n", cached);
 331 }
 332
 333 /*
 334  * Allocate and free page tables.
 335  */
 336
 337 pgd_t *pgd_alloc(struct mm_struct *mm)
 338 {
 339         pgd_t *pgd = (pgd_t *)__get_free_page(GFP_KERNEL);
 340
 341         if (pgd) {
 342                 memset(pgd, 0, USER_PTRS_PER_PGD * sizeof(pgd_t));
 343                 memcpy(pgd + USER_PTRS_PER_PGD,
 344                        swapper_pg_dir + USER_PTRS_PER_PGD,
 345                        (PTRS_PER_PGD - USER_PTRS_PER_PGD) * sizeof(pgd_t));
 346         }
 347         return pgd;
 348 }
 349
 350 void pgd_free(pgd_t *pgd)
 351 {
 352         free_page((unsigned long) pgd);
 353 }
 354
 355 pte_t *pte_alloc_one_kernel(struct mm_struct *mm, unsigned long address)
 356 {
 357         pte_t *pte;
 358
 359         pte = (pte_t *)__get_free_page(GFP_KERNEL|__GFP_REPEAT|__GFP_ZERO);
 360         return pte;
 361 }
 362
 363 struct page *pte_alloc_one(struct mm_struct *mm, unsigned long address)
 364 {
 365         struct page *pte;
 366
 367         pte = alloc_page(GFP_KERNEL|__GFP_REPEAT|__GFP_ZERO);
 368         return pte;
 369 }
 370
 371 /*
 372  * Overrides for Emacs so that we follow Linus's tabbing style.
 373  * Emacs will notice this stuff at the end of the file and automatically
 374  * adjust the settings for this buffer only.  This must remain at the end
 375  * of the file.
 376  * ---------------------------------------------------------------------------
 377  * Local variables:
 378  * c-file-style: "linux"
 379  * End:
 380  */