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/module.h>
   8 #include <linux/bootmem.h>
   9 #include <linux/highmem.h>
  10 #include <linux/mm.h>
  11 #include <linux/swap.h>
  12 #include <linux/slab.h>
  13 #include <asm/fixmap.h>
  14 #include <asm/page.h>
  15 #include "as-layout.h"
  16 #include "init.h"
  17 #include "kern.h"
  18 #include "kern_util.h"
  19 #include "mem_user.h"
  20 #include "os.h"
  21
  22 /* allocated in paging_init, zeroed in mem_init, and unchanged thereafter */
  23 unsigned long *empty_zero_page = NULL;
  24 EXPORT_SYMBOL(empty_zero_page);
  25 /* allocated in paging_init and unchanged thereafter */
  26 static unsigned long *empty_bad_page = NULL;
  27
  28 /*
  29  * Initialized during boot, and readonly for initializing page tables
  30  * afterwards
  31  */
  32 pgd_t swapper_pg_dir[PTRS_PER_PGD];
  33
  34 /* Initialized at boot time, and readonly after that */
  35 unsigned long long highmem;
  36 int kmalloc_ok = 0;
  37
  38 /* Used during early boot */
  39 static unsigned long brk_end;
  40
  41 #ifdef CONFIG_HIGHMEM
  42 static void setup_highmem(unsigned long highmem_start,
  43                           unsigned long highmem_len)
  44 {
  45         struct page *page;
  46         unsigned long highmem_pfn;
  47         int i;
  48
  49         highmem_pfn = __pa(highmem_start) >> PAGE_SHIFT;
  50         for (i = 0; i < highmem_len >> PAGE_SHIFT; i++) {
  51                 page = &mem_map[highmem_pfn + i];
  52                 ClearPageReserved(page);
  53                 init_page_count(page);
  54                 __free_page(page);
  55         }
  56 }
  57 #endif
  58
  59 void __init mem_init(void)
  60 {
  61         /* clear the zero-page */
  62         memset(empty_zero_page, 0, PAGE_SIZE);
  63
  64         /* Map in the area just after the brk now that kmalloc is about
  65          * to be turned on.
  66          */
  67         brk_end = (unsigned long) UML_ROUND_UP(sbrk(0));
  68         map_memory(brk_end, __pa(brk_end), uml_reserved - brk_end, 1, 1, 0);
  69         free_bootmem(__pa(brk_end), uml_reserved - brk_end);
  70         uml_reserved = brk_end;
  71
  72         /* this will put all low memory onto the freelists */
  73         totalram_pages = free_all_bootmem();
  74         max_low_pfn = totalram_pages;
  75 #ifdef CONFIG_HIGHMEM
  76         totalhigh_pages = highmem >> PAGE_SHIFT;
  77         totalram_pages += totalhigh_pages;
  78 #endif
  79         num_physpages = totalram_pages;
  80         max_pfn = totalram_pages;
  81         printk(KERN_INFO "Memory: %luk available\n",
  82                nr_free_pages() << (PAGE_SHIFT-10));
  83         kmalloc_ok = 1;
  84
  85 #ifdef CONFIG_HIGHMEM
  86         setup_highmem(end_iomem, highmem);
  87 #endif
  88 }
  89
  90 /*
  91  * Create a page table and place a pointer to it in a middle page
  92  * directory entry.
  93  */
  94 static void __init one_page_table_init(pmd_t *pmd)
  95 {
  96         if (pmd_none(*pmd)) {
  97                 pte_t *pte = (pte_t *) alloc_bootmem_low_pages(PAGE_SIZE);
  98                 set_pmd(pmd, __pmd(_KERNPG_TABLE +
  99                                            (unsigned long) __pa(pte)));
 100                 if (pte != pte_offset_kernel(pmd, 0))
 101                         BUG();
 102         }
 103 }
 104
 105 static void __init one_md_table_init(pud_t *pud)
 106 {
 107 #ifdef CONFIG_3_LEVEL_PGTABLES
 108         pmd_t *pmd_table = (pmd_t *) alloc_bootmem_low_pages(PAGE_SIZE);
 109         set_pud(pud, __pud(_KERNPG_TABLE + (unsigned long) __pa(pmd_table)));
 110         if (pmd_table != pmd_offset(pud, 0))
 111                 BUG();
 112 #endif
 113 }
 114
 115 static void __init fixrange_init(unsigned long start, unsigned long end,
 116                                  pgd_t *pgd_base)
 117 {
 118         pgd_t *pgd;
 119         pud_t *pud;
 120         pmd_t *pmd;
 121         int i, j;
 122         unsigned long vaddr;
 123
 124         vaddr = start;
 125         i = pgd_index(vaddr);
 126         j = pmd_index(vaddr);
 127         pgd = pgd_base + i;
 128
 129         for ( ; (i < PTRS_PER_PGD) && (vaddr < end); pgd++, i++) {
 130                 pud = pud_offset(pgd, vaddr);
 131                 if (pud_none(*pud))
 132                         one_md_table_init(pud);
 133                 pmd = pmd_offset(pud, vaddr);
 134                 for (; (j < PTRS_PER_PMD) && (vaddr < end); pmd++, j++) {
 135                         one_page_table_init(pmd);
 136                         vaddr += PMD_SIZE;
 137                 }
 138                 j = 0;
 139         }
 140 }
 141
 142 #ifdef CONFIG_HIGHMEM
 143 pte_t *kmap_pte;
 144 pgprot_t kmap_prot;
 145
 146 #define kmap_get_fixmap_pte(vaddr)                                      \
 147         pte_offset_kernel(pmd_offset(pud_offset(pgd_offset_k(vaddr), (vaddr)),\
 148                                      (vaddr)), (vaddr))
 149
 150 static void __init kmap_init(void)
 151 {
 152         unsigned long kmap_vstart;
 153
 154         /* cache the first kmap pte */
 155         kmap_vstart = __fix_to_virt(FIX_KMAP_BEGIN);
 156         kmap_pte = kmap_get_fixmap_pte(kmap_vstart);
 157
 158         kmap_prot = PAGE_KERNEL;
 159 }
 160
 161 static void __init init_highmem(void)
 162 {
 163         pgd_t *pgd;
 164         pud_t *pud;
 165         pmd_t *pmd;
 166         pte_t *pte;
 167         unsigned long vaddr;
 168
 169         /*
 170          * Permanent kmaps:
 171          */
 172         vaddr = PKMAP_BASE;
 173         fixrange_init(vaddr, vaddr + PAGE_SIZE*LAST_PKMAP, swapper_pg_dir);
 174
 175         pgd = swapper_pg_dir + pgd_index(vaddr);
 176         pud = pud_offset(pgd, vaddr);
 177         pmd = pmd_offset(pud, vaddr);
 178         pte = pte_offset_kernel(pmd, vaddr);
 179         pkmap_page_table = pte;
 180
 181         kmap_init();
 182 }
 183 #endif /* CONFIG_HIGHMEM */
 184
 185 static void __init fixaddr_user_init( void)
 186 {
 187 #ifdef CONFIG_ARCH_REUSE_HOST_VSYSCALL_AREA
 188         long size = FIXADDR_USER_END - FIXADDR_USER_START;
 189         pgd_t *pgd;
 190         pud_t *pud;
 191         pmd_t *pmd;
 192         pte_t *pte;
 193         phys_t p;
 194         unsigned long v, vaddr = FIXADDR_USER_START;
 195
 196         if (!size)
 197                 return;
 198
 199         fixrange_init( FIXADDR_USER_START, FIXADDR_USER_END, swapper_pg_dir);
 200         v = (unsigned long) alloc_bootmem_low_pages(size);
 201         memcpy((void *) v , (void *) FIXADDR_USER_START, size);
 202         p = __pa(v);
 203         for ( ; size > 0; size -= PAGE_SIZE, vaddr += PAGE_SIZE,
 204                       p += PAGE_SIZE) {
 205                 pgd = swapper_pg_dir + pgd_index(vaddr);
 206                 pud = pud_offset(pgd, vaddr);
 207                 pmd = pmd_offset(pud, vaddr);
 208                 pte = pte_offset_kernel(pmd, vaddr);
 209                 pte_set_val(*pte, p, PAGE_READONLY);
 210         }
 211 #endif
 212 }
 213
 214 void __init paging_init(void)
 215 {
 216         unsigned long zones_size[MAX_NR_ZONES], vaddr;
 217         int i;
 218
 219         empty_zero_page = (unsigned long *) alloc_bootmem_low_pages(PAGE_SIZE);
 220         empty_bad_page = (unsigned long *) alloc_bootmem_low_pages(PAGE_SIZE);
 221         for (i = 0; i < ARRAY_SIZE(zones_size); i++)
 222                 zones_size[i] = 0;
 223
 224         zones_size[ZONE_NORMAL] = (end_iomem >> PAGE_SHIFT) -
 225                 (uml_physmem >> PAGE_SHIFT);
 226 #ifdef CONFIG_HIGHMEM
 227         zones_size[ZONE_HIGHMEM] = highmem >> PAGE_SHIFT;
 228 #endif
 229         free_area_init(zones_size);
 230
 231         /*
 232          * Fixed mappings, only the page table structure has to be
 233          * created - mappings will be set by set_fixmap():
 234          */
 235         vaddr = __fix_to_virt(__end_of_fixed_addresses - 1) & PMD_MASK;
 236         fixrange_init(vaddr, FIXADDR_TOP, swapper_pg_dir);
 237
 238         fixaddr_user_init();
 239
 240 #ifdef CONFIG_HIGHMEM
 241         init_highmem();
 242 #endif
 243 }
 244
 245 /*
 246  * This can't do anything because nothing in the kernel image can be freed
 247  * since it's not in kernel physical memory.
 248  */
 249
 250 void free_initmem(void)
 251 {
 252 }
 253
 254 #ifdef CONFIG_BLK_DEV_INITRD
 255 void free_initrd_mem(unsigned long start, unsigned long end)
 256 {
 257         if (start < end)
 258                 printk(KERN_INFO "Freeing initrd memory: %ldk freed\n",
 259                        (end - start) >> 10);
 260         for (; start < end; start += PAGE_SIZE) {
 261                 ClearPageReserved(virt_to_page(start));
 262                 init_page_count(virt_to_page(start));
 263                 free_page(start);
 264                 totalram_pages++;
 265         }
 266 }
 267 #endif
 268
 269 /* Allocate and free page tables. */
 270
 271 pgd_t *pgd_alloc(struct mm_struct *mm)
 272 {
 273         pgd_t *pgd = (pgd_t *)__get_free_page(GFP_KERNEL);
 274
 275         if (pgd) {
 276                 memset(pgd, 0, USER_PTRS_PER_PGD * sizeof(pgd_t));
 277                 memcpy(pgd + USER_PTRS_PER_PGD,
 278                        swapper_pg_dir + USER_PTRS_PER_PGD,
 279                        (PTRS_PER_PGD - USER_PTRS_PER_PGD) * sizeof(pgd_t));
 280         }
 281         return pgd;
 282 }
 283
 284 void pgd_free(struct mm_struct *mm, pgd_t *pgd)
 285 {
 286         free_page((unsigned long) pgd);
 287 }
 288
 289 pte_t *pte_alloc_one_kernel(struct mm_struct *mm, unsigned long address)
 290 {
 291         pte_t *pte;
 292
 293         pte = (pte_t *)__get_free_page(GFP_KERNEL|__GFP_REPEAT|__GFP_ZERO);
 294         return pte;
 295 }
 296
 297 pgtable_t pte_alloc_one(struct mm_struct *mm, unsigned long address)
 298 {
 299         struct page *pte;
 300
 301         pte = alloc_page(GFP_KERNEL|__GFP_REPEAT|__GFP_ZERO);
 302         if (pte)
 303                 pgtable_page_ctor(pte);
 304         return pte;
 305 }
 306
 307 #ifdef CONFIG_3_LEVEL_PGTABLES
 308 pmd_t *pmd_alloc_one(struct mm_struct *mm, unsigned long address)
 309 {
 310         pmd_t *pmd = (pmd_t *) __get_free_page(GFP_KERNEL);
 311
 312         if (pmd)
 313                 memset(pmd, 0, PAGE_SIZE);
 314
 315         return pmd;
 316 }
 317 #endif
 318
 319 void *uml_kmalloc(int size, int flags)
 320 {
 321         return kmalloc(size, flags);
 322 }