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