arch/x86/mm/init.c

   1 #include <linux/initrd.h>
   2 #include <linux/ioport.h>
   3 #include <linux/swap.h>
   4
   5 #include <asm/cacheflush.h>
   6 #include <asm/e820.h>
   7 #include <asm/init.h>
   8 #include <asm/page.h>
   9 #include <asm/page_types.h>
  10 #include <asm/sections.h>
  11 #include <asm/setup.h>
  12 #include <asm/system.h>
  13 #include <asm/tlbflush.h>
  14 #include <asm/tlb.h>
  15 #include <asm/proto.h>
  16
  17 DEFINE_PER_CPU(struct mmu_gather, mmu_gathers);
  18
  19 unsigned long __initdata e820_table_start;
  20 unsigned long __meminitdata e820_table_end;
  21 unsigned long __meminitdata e820_table_top;
  22
  23 int after_bootmem;
  24
  25 int direct_gbpages
  26 #ifdef CONFIG_DIRECT_GBPAGES
  27                                 = 1
  28 #endif
  29 ;
  30
  31 static void __init find_early_table_space(unsigned long end, int use_pse,
  32                                           int use_gbpages)
  33 {
  34         unsigned long puds, pmds, ptes, tables, start;
  35
  36         puds = (end + PUD_SIZE - 1) >> PUD_SHIFT;
  37         tables = roundup(puds * sizeof(pud_t), PAGE_SIZE);
  38
  39         if (use_gbpages) {
  40                 unsigned long extra;
  41
  42                 extra = end - ((end>>PUD_SHIFT) << PUD_SHIFT);
  43                 pmds = (extra + PMD_SIZE - 1) >> PMD_SHIFT;
  44         } else
  45                 pmds = (end + PMD_SIZE - 1) >> PMD_SHIFT;
  46
  47         tables += roundup(pmds * sizeof(pmd_t), PAGE_SIZE);
  48
  49         if (use_pse) {
  50                 unsigned long extra;
  51
  52                 extra = end - ((end>>PMD_SHIFT) << PMD_SHIFT);
  53 #ifdef CONFIG_X86_32
  54                 extra += PMD_SIZE;
  55 #endif
  56                 ptes = (extra + PAGE_SIZE - 1) >> PAGE_SHIFT;
  57         } else
  58                 ptes = (end + PAGE_SIZE - 1) >> PAGE_SHIFT;
  59
  60         tables += roundup(ptes * sizeof(pte_t), PAGE_SIZE);
  61
  62 #ifdef CONFIG_X86_32
  63         /* for fixmap */
  64         tables += roundup(__end_of_fixed_addresses * sizeof(pte_t), PAGE_SIZE);
  65 #endif
  66
  67         /*
  68          * RED-PEN putting page tables only on node 0 could
  69          * cause a hotspot and fill up ZONE_DMA. The page tables
  70          * need roughly 0.5KB per GB.
  71          */
  72 #ifdef CONFIG_X86_32
  73         start = 0x7000;
  74 #else
  75         start = 0x8000;
  76 #endif
  77         e820_table_start = find_e820_area(start, max_pfn_mapped<<PAGE_SHIFT,
  78                                         tables, PAGE_SIZE);
  79         if (e820_table_start == -1UL)
  80                 panic("Cannot find space for the kernel page tables");
  81
  82         e820_table_start >>= PAGE_SHIFT;
  83         e820_table_end = e820_table_start;
  84         e820_table_top = e820_table_start + (tables >> PAGE_SHIFT);
  85
  86         printk(KERN_DEBUG "kernel direct mapping tables up to %lx @ %lx-%lx\n",
  87                 end, e820_table_start << PAGE_SHIFT, e820_table_top << PAGE_SHIFT);
  88 }
  89
  90 struct map_range {
  91         unsigned long start;
  92         unsigned long end;
  93         unsigned page_size_mask;
  94 };
  95
  96 #ifdef CONFIG_X86_32
  97 #define NR_RANGE_MR 3
  98 #else /* CONFIG_X86_64 */
  99 #define NR_RANGE_MR 5
 100 #endif
 101
 102 static int __meminit save_mr(struct map_range *mr, int nr_range,
 103                              unsigned long start_pfn, unsigned long end_pfn,
 104                              unsigned long page_size_mask)
 105 {
 106         if (start_pfn < end_pfn) {
 107                 if (nr_range >= NR_RANGE_MR)
 108                         panic("run out of range for init_memory_mapping\n");
 109                 mr[nr_range].start = start_pfn<<PAGE_SHIFT;
 110                 mr[nr_range].end   = end_pfn<<PAGE_SHIFT;
 111                 mr[nr_range].page_size_mask = page_size_mask;
 112                 nr_range++;
 113         }
 114
 115         return nr_range;
 116 }
 117
 118 /*
 119  * Setup the direct mapping of the physical memory at PAGE_OFFSET.
 120  * This runs before bootmem is initialized and gets pages directly from
 121  * the physical memory. To access them they are temporarily mapped.
 122  */
 123 unsigned long __init_refok init_memory_mapping(unsigned long start,
 124                                                unsigned long end)
 125 {
 126         unsigned long page_size_mask = 0;
 127         unsigned long start_pfn, end_pfn;
 128         unsigned long ret = 0;
 129         unsigned long pos;
 130
 131         struct map_range mr[NR_RANGE_MR];
 132         int nr_range, i;
 133         int use_pse, use_gbpages;
 134
 135         printk(KERN_INFO "init_memory_mapping: %016lx-%016lx\n", start, end);
 136
 137 #if defined(CONFIG_DEBUG_PAGEALLOC) || defined(CONFIG_KMEMCHECK)
 138         /*
 139          * For CONFIG_DEBUG_PAGEALLOC, identity mapping will use small pages.
 140          * This will simplify cpa(), which otherwise needs to support splitting
 141          * large pages into small in interrupt context, etc.
 142          */
 143         use_pse = use_gbpages = 0;
 144 #else
 145         use_pse = cpu_has_pse;
 146         use_gbpages = direct_gbpages;
 147 #endif
 148
 149         set_nx();
 150         if (nx_enabled)
 151                 printk(KERN_INFO "NX (Execute Disable) protection: active\n");
 152
 153         /* Enable PSE if available */
 154         if (cpu_has_pse)
 155                 set_in_cr4(X86_CR4_PSE);
 156
 157         /* Enable PGE if available */
 158         if (cpu_has_pge) {
 159                 set_in_cr4(X86_CR4_PGE);
 160                 __supported_pte_mask |= _PAGE_GLOBAL;
 161         }
 162
 163         if (use_gbpages)
 164                 page_size_mask |= 1 << PG_LEVEL_1G;
 165         if (use_pse)
 166                 page_size_mask |= 1 << PG_LEVEL_2M;
 167
 168         memset(mr, 0, sizeof(mr));
 169         nr_range = 0;
 170
 171         /* head if not big page alignment ? */
 172         start_pfn = start >> PAGE_SHIFT;
 173         pos = start_pfn << PAGE_SHIFT;
 174 #ifdef CONFIG_X86_32
 175         /*
 176          * Don't use a large page for the first 2/4MB of memory
 177          * because there are often fixed size MTRRs in there
 178          * and overlapping MTRRs into large pages can cause
 179          * slowdowns.
 180          */
 181         if (pos == 0)
 182                 end_pfn = 1<<(PMD_SHIFT - PAGE_SHIFT);
 183         else
 184                 end_pfn = ((pos + (PMD_SIZE - 1))>>PMD_SHIFT)
 185                                  << (PMD_SHIFT - PAGE_SHIFT);
 186 #else /* CONFIG_X86_64 */
 187         end_pfn = ((pos + (PMD_SIZE - 1)) >> PMD_SHIFT)
 188                         << (PMD_SHIFT - PAGE_SHIFT);
 189 #endif
 190         if (end_pfn > (end >> PAGE_SHIFT))
 191                 end_pfn = end >> PAGE_SHIFT;
 192         if (start_pfn < end_pfn) {
 193                 nr_range = save_mr(mr, nr_range, start_pfn, end_pfn, 0);
 194                 pos = end_pfn << PAGE_SHIFT;
 195         }
 196
 197         /* big page (2M) range */
 198         start_pfn = ((pos + (PMD_SIZE - 1))>>PMD_SHIFT)
 199                          << (PMD_SHIFT - PAGE_SHIFT);
 200 #ifdef CONFIG_X86_32
 201         end_pfn = (end>>PMD_SHIFT) << (PMD_SHIFT - PAGE_SHIFT);
 202 #else /* CONFIG_X86_64 */
 203         end_pfn = ((pos + (PUD_SIZE - 1))>>PUD_SHIFT)
 204                          << (PUD_SHIFT - PAGE_SHIFT);
 205         if (end_pfn > ((end>>PMD_SHIFT)<<(PMD_SHIFT - PAGE_SHIFT)))
 206                 end_pfn = ((end>>PMD_SHIFT)<<(PMD_SHIFT - PAGE_SHIFT));
 207 #endif
 208
 209         if (start_pfn < end_pfn) {
 210                 nr_range = save_mr(mr, nr_range, start_pfn, end_pfn,
 211                                 page_size_mask & (1<<PG_LEVEL_2M));
 212                 pos = end_pfn << PAGE_SHIFT;
 213         }
 214
 215 #ifdef CONFIG_X86_64
 216         /* big page (1G) range */
 217         start_pfn = ((pos + (PUD_SIZE - 1))>>PUD_SHIFT)
 218                          << (PUD_SHIFT - PAGE_SHIFT);
 219         end_pfn = (end >> PUD_SHIFT) << (PUD_SHIFT - PAGE_SHIFT);
 220         if (start_pfn < end_pfn) {
 221                 nr_range = save_mr(mr, nr_range, start_pfn, end_pfn,
 222                                 page_size_mask &
 223                                  ((1<<PG_LEVEL_2M)|(1<<PG_LEVEL_1G)));
 224                 pos = end_pfn << PAGE_SHIFT;
 225         }
 226
 227         /* tail is not big page (1G) alignment */
 228         start_pfn = ((pos + (PMD_SIZE - 1))>>PMD_SHIFT)
 229                          << (PMD_SHIFT - PAGE_SHIFT);
 230         end_pfn = (end >> PMD_SHIFT) << (PMD_SHIFT - PAGE_SHIFT);
 231         if (start_pfn < end_pfn) {
 232                 nr_range = save_mr(mr, nr_range, start_pfn, end_pfn,
 233                                 page_size_mask & (1<<PG_LEVEL_2M));
 234                 pos = end_pfn << PAGE_SHIFT;
 235         }
 236 #endif
 237
 238         /* tail is not big page (2M) alignment */
 239         start_pfn = pos>>PAGE_SHIFT;
 240         end_pfn = end>>PAGE_SHIFT;
 241         nr_range = save_mr(mr, nr_range, start_pfn, end_pfn, 0);
 242
 243         /* try to merge same page size and continuous */
 244         for (i = 0; nr_range > 1 && i < nr_range - 1; i++) {
 245                 unsigned long old_start;
 246                 if (mr[i].end != mr[i+1].start ||
 247                     mr[i].page_size_mask != mr[i+1].page_size_mask)
 248                         continue;
 249                 /* move it */
 250                 old_start = mr[i].start;
 251                 memmove(&mr[i], &mr[i+1],
 252                         (nr_range - 1 - i) * sizeof(struct map_range));
 253                 mr[i--].start = old_start;
 254                 nr_range--;
 255         }
 256
 257         for (i = 0; i < nr_range; i++)
 258                 printk(KERN_DEBUG " %010lx - %010lx page %s\n",
 259                                 mr[i].start, mr[i].end,
 260                         (mr[i].page_size_mask & (1<<PG_LEVEL_1G))?"1G":(
 261                          (mr[i].page_size_mask & (1<<PG_LEVEL_2M))?"2M":"4k"));
 262
 263         /*
 264          * Find space for the kernel direct mapping tables.
 265          *
 266          * Later we should allocate these tables in the local node of the
 267          * memory mapped. Unfortunately this is done currently before the
 268          * nodes are discovered.
 269          */
 270         if (!after_bootmem)
 271                 find_early_table_space(end, use_pse, use_gbpages);
 272
 273 #ifdef CONFIG_X86_32
 274         for (i = 0; i < nr_range; i++)
 275                 kernel_physical_mapping_init(mr[i].start, mr[i].end,
 276                                              mr[i].page_size_mask);
 277         ret = end;
 278 #else /* CONFIG_X86_64 */
 279         for (i = 0; i < nr_range; i++)
 280                 ret = kernel_physical_mapping_init(mr[i].start, mr[i].end,
 281                                                    mr[i].page_size_mask);
 282 #endif
 283
 284 #ifdef CONFIG_X86_32
 285         early_ioremap_page_table_range_init();
 286
 287         load_cr3(swapper_pg_dir);
 288 #endif
 289
 290 #ifdef CONFIG_X86_64
 291         if (!after_bootmem && !start) {
 292                 pud_t *pud;
 293                 pmd_t *pmd;
 294
 295                 mmu_cr4_features = read_cr4();
 296
 297                 /*
 298                  * _brk_end cannot change anymore, but it and _end may be
 299                  * located on different 2M pages. cleanup_highmap(), however,
 300                  * can only consider _end when it runs, so destroy any
 301                  * mappings beyond _brk_end here.
 302                  */
 303                 pud = pud_offset(pgd_offset_k(_brk_end), _brk_end);
 304                 pmd = pmd_offset(pud, _brk_end - 1);
 305                 while (++pmd <= pmd_offset(pud, (unsigned long)_end - 1))
 306                         pmd_clear(pmd);
 307         }
 308 #endif
 309         __flush_tlb_all();
 310
 311         if (!after_bootmem && e820_table_end > e820_table_start)
 312                 reserve_early(e820_table_start << PAGE_SHIFT,
 313                                  e820_table_end << PAGE_SHIFT, "PGTABLE");
 314
 315         if (!after_bootmem)
 316                 early_memtest(start, end);
 317
 318         return ret >> PAGE_SHIFT;
 319 }
 320
 321
 322 /*
 323  * devmem_is_allowed() checks to see if /dev/mem access to a certain address
 324  * is valid. The argument is a physical page number.
 325  *
 326  *
 327  * On x86, access has to be given to the first megabyte of ram because that area
 328  * contains bios code and data regions used by X and dosemu and similar apps.
 329  * Access has to be given to non-kernel-ram areas as well, these contain the PCI
 330  * mmio resources as well as potential bios/acpi data regions.
 331  */
 332 int devmem_is_allowed(unsigned long pagenr)
 333 {
 334         if (pagenr <= 256)
 335                 return 1;
 336         if (iomem_is_exclusive(pagenr << PAGE_SHIFT))
 337                 return 0;
 338         if (!page_is_ram(pagenr))
 339                 return 1;
 340         return 0;
 341 }
 342
 343 void free_init_pages(char *what, unsigned long begin, unsigned long end)
 344 {
 345         unsigned long addr = begin;
 346
 347         if (addr >= end)
 348                 return;
 349
 350         /*
 351          * If debugging page accesses then do not free this memory but
 352          * mark them not present - any buggy init-section access will
 353          * create a kernel page fault:
 354          */
 355 #ifdef CONFIG_DEBUG_PAGEALLOC
 356         printk(KERN_INFO "debug: unmapping init memory %08lx..%08lx\n",
 357                 begin, PAGE_ALIGN(end));
 358         set_memory_np(begin, (end - begin) >> PAGE_SHIFT);
 359 #else
 360         /*
 361          * We just marked the kernel text read only above, now that
 362          * we are going to free part of that, we need to make that
 363          * writeable first.
 364          */
 365         set_memory_rw(begin, (end - begin) >> PAGE_SHIFT);
 366
 367         printk(KERN_INFO "Freeing %s: %luk freed\n", what, (end - begin) >> 10);
 368
 369         for (; addr < end; addr += PAGE_SIZE) {
 370                 ClearPageReserved(virt_to_page(addr));
 371                 init_page_count(virt_to_page(addr));
 372                 memset((void *)(addr & ~(PAGE_SIZE-1)),
 373                         POISON_FREE_INITMEM, PAGE_SIZE);
 374                 free_page(addr);
 375                 totalram_pages++;
 376         }
 377 #endif
 378 }
 379
 380 void free_initmem(void)
 381 {
 382         free_init_pages("unused kernel memory",
 383                         (unsigned long)(&__init_begin),
 384                         (unsigned long)(&__init_end));
 385 }
 386
 387 #ifdef CONFIG_BLK_DEV_INITRD
 388 void free_initrd_mem(unsigned long start, unsigned long end)
 389 {
 390         free_init_pages("initrd memory", start, end);
 391 }
 392 #endif