arch/um/kernel/mem.c

   1 /*
   2  * Copyright (C) 2000 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
   3  * Licensed under the GPL
   4  */
   5
   6 #include <linux/stddef.h>
   7 #include <linux/bootmem.h>
   8 #include <linux/gfp.h>
   9 #include <linux/highmem.h>
  10 #include <linux/mm.h>
  11 #include <linux/swap.h>
  12 #include <asm/fixmap.h>
  13 #include <asm/page.h>
  14 #include "as-layout.h"
  15 #include "init.h"
  16 #include "kern.h"
  17 #include "kern_util.h"
  18 #include "mem_user.h"
  19 #include "os.h"
  20
  21 /* allocated in paging_init, zeroed in mem_init, and unchanged thereafter */
  22 unsigned long *empty_zero_page = NULL;
  23 /* allocated in paging_init and unchanged thereafter */
  24 static unsigned long *empty_bad_page = NULL;
  25
  26 /*
  27  * Initialized during boot, and readonly for initializing page tables
  28  * afterwards
  29  */
  30 pgd_t swapper_pg_dir[PTRS_PER_PGD];
  31
  32 /* Initialized at boot time, and readonly after that */
  33 unsigned long long highmem;
  34 int kmalloc_ok = 0;
  35
  36 /* Used during early boot */
  37 static unsigned long brk_end;
  38
  39 #ifdef CONFIG_HIGHMEM
  40 static void setup_highmem(unsigned long highmem_start,
  41                           unsigned long highmem_len)
  42 {
  43         struct page *page;
  44         unsigned long highmem_pfn;
  45         int i;
  46
  47         highmem_pfn = __pa(highmem_start) >> PAGE_SHIFT;
  48         for (i = 0; i < highmem_len >> PAGE_SHIFT; i++) {
  49                 page = &mem_map[highmem_pfn + i];
  50                 ClearPageReserved(page);
  51                 init_page_count(page);
  52                 __free_page(page);
  53         }
  54 }
  55 #endif
  56
  57 void __init mem_init(void)
  58 {
  59         /* clear the zero-page */
  60         memset(empty_zero_page, 0, PAGE_SIZE);
  61
  62         /* Map in the area just after the brk now that kmalloc is about
  63          * to be turned on.
  64          */
  65         brk_end = (unsigned long) UML_ROUND_UP(sbrk(0));
  66         map_memory(brk_end, __pa(brk_end), uml_reserved - brk_end, 1, 1, 0);
  67         free_bootmem(__pa(brk_end), uml_reserved - brk_end);
  68         uml_reserved = brk_end;
  69
  70         /* this will put all low memory onto the freelists */
  71         totalram_pages = free_all_bootmem();
  72         max_low_pfn = totalram_pages;
  73 #ifdef CONFIG_HIGHMEM
  74         totalhigh_pages = highmem >> PAGE_SHIFT;
  75         totalram_pages += totalhigh_pages;
  76 #endif
  77         num_physpages = totalram_pages;
  78         max_pfn = totalram_pages;
  79         printk(KERN_INFO "Memory: %luk available\n",
  80                (unsigned long) nr_free_pages() << (PAGE_SHIFT-10));
  81         kmalloc_ok = 1;
  82
  83 #ifdef CONFIG_HIGHMEM
  84         setup_highmem(end_iomem, highmem);
  85 #endif
  86 }
  87
  88 /*
  89  * Create a page table and place a pointer to it in a middle page
  90  * directory entry.
  91  */
  92 static void __init one_page_table_init(pmd_t *pmd)
  93 {
  94         if (pmd_none(*pmd)) {
  95                 pte_t *pte = (pte_t *) alloc_bootmem_low_pages(PAGE_SIZE);
  96                 set_pmd(pmd, __pmd(_KERNPG_TABLE +
  97                                            (unsigned long) __pa(pte)));
  98                 if (pte != pte_offset_kernel(pmd, 0))
  99                         BUG();
 100         }
 101 }
 102
 103 static void __init one_md_table_init(pud_t *pud)
 104 {
 105 #ifdef CONFIG_3_LEVEL_PGTABLES
 106         pmd_t *pmd_table = (pmd_t *) alloc_bootmem_low_pages(PAGE_SIZE);
 107         set_pud(pud, __pud(_KERNPG_TABLE + (unsigned long) __pa(pmd_table)));
 108         if (pmd_table != pmd_offset(pud, 0))
 109                 BUG();
 110 #endif
 111 }
 112
 113 static void __init fixrange_init(unsigned long start, unsigned long end,
 114                                  pgd_t *pgd_base)
 115 {
 116         pgd_t *pgd;
 117         pud_t *pud;
 118         pmd_t *pmd;
 119         int i, j;
 120         unsigned long vaddr;
 121
 122         vaddr = start;
 123         i = pgd_index(vaddr);
 124         j = pmd_index(vaddr);
 125         pgd = pgd_base + i;
 126
 127         for ( ; (i < PTRS_PER_PGD) && (vaddr < end); pgd++, i++) {
 128                 pud = pud_offset(pgd, vaddr);
 129                 if (pud_none(*pud))
 130                         one_md_table_init(pud);
 131                 pmd = pmd_offset(pud, vaddr);
 132                 for (; (j < PTRS_PER_PMD) && (vaddr < end); pmd++, j++) {
 133                         one_page_table_init(pmd);
 134                         vaddr += PMD_SIZE;
 135                 }
 136                 j = 0;
 137         }
 138 }
 139
 140 #ifdef CONFIG_HIGHMEM
 141 pte_t *kmap_pte;
 142 pgprot_t kmap_prot;
 143
 144 #define kmap_get_fixmap_pte(vaddr)                                      \
 145         pte_offset_kernel(pmd_offset(pud_offset(pgd_offset_k(vaddr), (vaddr)),\
 146                                      (vaddr)), (vaddr))
 147
 148 static void __init kmap_init(void)
 149 {
 150         unsigned long kmap_vstart;
 151
 152         /* cache the first kmap pte */
 153         kmap_vstart = __fix_to_virt(FIX_KMAP_BEGIN);
 154         kmap_pte = kmap_get_fixmap_pte(kmap_vstart);
 155
 156         kmap_prot = PAGE_KERNEL;
 157 }
 158
 159 static void __init init_highmem(void)
 160 {
 161         pgd_t *pgd;
 162         pud_t *pud;
 163         pmd_t *pmd;
 164         pte_t *pte;
 165         unsigned long vaddr;
 166
 167         /*
 168          * Permanent kmaps:
 169          */
 170         vaddr = PKMAP_BASE;
 171         fixrange_init(vaddr, vaddr + PAGE_SIZE*LAST_PKMAP, swapper_pg_dir);
 172
 173         pgd = swapper_pg_dir + pgd_index(vaddr);
 174         pud = pud_offset(pgd, vaddr);
 175         pmd = pmd_offset(pud, vaddr);
 176         pte = pte_offset_kernel(pmd, vaddr);
 177         pkmap_page_table = pte;
 178
 179         kmap_init();
 180 }
 181 #endif /* CONFIG_HIGHMEM */
 182
 183 static void __init fixaddr_user_init( void)
 184 {
 185 #ifdef CONFIG_ARCH_REUSE_HOST_VSYSCALL_AREA
 186         long size = FIXADDR_USER_END - FIXADDR_USER_START;
 187         pgd_t *pgd;
 188         pud_t *pud;
 189         pmd_t *pmd;
 190         pte_t *pte;
 191         phys_t p;
 192         unsigned long v, vaddr = FIXADDR_USER_START;
 193
 194         if (!size)
 195                 return;
 196
 197         fixrange_init( FIXADDR_USER_START, FIXADDR_USER_END, swapper_pg_dir);
 198         v = (unsigned long) alloc_bootmem_low_pages(size);
 199         memcpy((void *) v , (void *) FIXADDR_USER_START, size);
 200         p = __pa(v);
 201         for ( ; size > 0; size -= PAGE_SIZE, vaddr += PAGE_SIZE,
 202                       p += PAGE_SIZE) {
 203                 pgd = swapper_pg_dir + pgd_index(vaddr);
 204                 pud = pud_offset(pgd, vaddr);
 205                 pmd = pmd_offset(pud, vaddr);
 206                 pte = pte_offset_kernel(pmd, vaddr);
 207                 pte_set_val(*pte, p, PAGE_READONLY);
 208         }
 209 #endif
 210 }
 211
 212 void __init paging_init(void)
 213 {
 214         unsigned long zones_size[MAX_NR_ZONES], vaddr;
 215         int i;
 216
 217         empty_zero_page = (unsigned long *) alloc_bootmem_low_pages(PAGE_SIZE);
 218         empty_bad_page = (unsigned long *) alloc_bootmem_low_pages(PAGE_SIZE);
 219         for (i = 0; i < ARRAY_SIZE(zones_size); i++)
 220                 zones_size[i] = 0;
 221
 222         zones_size[ZONE_NORMAL] = (end_iomem >> PAGE_SHIFT) -
 223                 (uml_physmem >> PAGE_SHIFT);
 224 #ifdef CONFIG_HIGHMEM
 225         zones_size[ZONE_HIGHMEM] = highmem >> PAGE_SHIFT;
 226 #endif
 227         free_area_init(zones_size);
 228
 229         /*
 230          * Fixed mappings, only the page table structure has to be
 231          * created - mappings will be set by set_fixmap():
 232          */
 233         vaddr = __fix_to_virt(__end_of_fixed_addresses - 1) & PMD_MASK;
 234         fixrange_init(vaddr, FIXADDR_TOP, swapper_pg_dir);
 235
 236         fixaddr_user_init();
 237
 238 #ifdef CONFIG_HIGHMEM
 239         init_highmem();
 240 #endif
 241 }
 242
 243 /*
 244  * This can't do anything because nothing in the kernel image can be freed
 245  * since it's not in kernel physical memory.
 246  */
 247
 248 void free_initmem(void)
 249 {
 250 }
 251
 252 #ifdef CONFIG_BLK_DEV_INITRD
 253 void free_initrd_mem(unsigned long start, unsigned long end)
 254 {
 255         if (start < end)
 256                 printk(KERN_INFO "Freeing initrd memory: %ldk freed\n",
 257                        (end - start) >> 10);
 258         for (; start < end; start += PAGE_SIZE) {
 259                 ClearPageReserved(virt_to_page(start));
 260                 init_page_count(virt_to_page(start));
 261                 free_page(start);
 262                 totalram_pages++;
 263         }
 264 }
 265 #endif
 266
 267 /* Allocate and free page tables. */
 268
 269 pgd_t *pgd_alloc(struct mm_struct *mm)
 270 {
 271         pgd_t *pgd = (pgd_t *)__get_free_page(GFP_KERNEL);
 272
 273         if (pgd) {
 274                 memset(pgd, 0, USER_PTRS_PER_PGD * sizeof(pgd_t));
 275                 memcpy(pgd + USER_PTRS_PER_PGD,
 276                        swapper_pg_dir + USER_PTRS_PER_PGD,
 277                        (PTRS_PER_PGD - USER_PTRS_PER_PGD) * sizeof(pgd_t));
 278         }
 279         return pgd;
 280 }
 281
 282 void pgd_free(struct mm_struct *mm, pgd_t *pgd)
 283 {
 284         free_page((unsigned long) pgd);
 285 }
 286
 287 pte_t *pte_alloc_one_kernel(struct mm_struct *mm, unsigned long address)
 288 {
 289         pte_t *pte;
 290
 291         pte = (pte_t *)__get_free_page(GFP_KERNEL|__GFP_REPEAT|__GFP_ZERO);
 292         return pte;
 293 }
 294
 295 pgtable_t pte_alloc_one(struct mm_struct *mm, unsigned long address)
 296 {
 297         struct page *pte;
 298
 299         pte = alloc_page(GFP_KERNEL|__GFP_REPEAT|__GFP_ZERO);
 300         if (pte)
 301                 pgtable_page_ctor(pte);
 302         return pte;
 303 }
 304
 305 #ifdef CONFIG_3_LEVEL_PGTABLES
 306 pmd_t *pmd_alloc_one(struct mm_struct *mm, unsigned long address)
 307 {
 308         pmd_t *pmd = (pmd_t *) __get_free_page(GFP_KERNEL);
 309
 310         if (pmd)
 311                 memset(pmd, 0, PAGE_SIZE);
 312
 313         return pmd;
 314 }
 315 #endif
 316
 317 void *uml_kmalloc(int size, int flags)
 318 {
 319         return kmalloc(size, flags);
 320 }