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         /* Enable PSE if available */
 150         if (cpu_has_pse)
 151                 set_in_cr4(X86_CR4_PSE);
 152
 153         /* Enable PGE if available */
 154         if (cpu_has_pge) {
 155                 set_in_cr4(X86_CR4_PGE);
 156                 __supported_pte_mask |= _PAGE_GLOBAL;
 157         }
 158
 159         if (use_gbpages)
 160                 page_size_mask |= 1 << PG_LEVEL_1G;
 161         if (use_pse)
 162                 page_size_mask |= 1 << PG_LEVEL_2M;
 163
 164         memset(mr, 0, sizeof(mr));
 165         nr_range = 0;
 166
 167         /* head if not big page alignment ? */
 168         start_pfn = start >> PAGE_SHIFT;
 169         pos = start_pfn << PAGE_SHIFT;
 170 #ifdef CONFIG_X86_32
 171         /*
 172          * Don't use a large page for the first 2/4MB of memory
 173          * because there are often fixed size MTRRs in there
 174          * and overlapping MTRRs into large pages can cause
 175          * slowdowns.
 176          */
 177         if (pos == 0)
 178                 end_pfn = 1<<(PMD_SHIFT - PAGE_SHIFT);
 179         else
 180                 end_pfn = ((pos + (PMD_SIZE - 1))>>PMD_SHIFT)
 181                                  << (PMD_SHIFT - PAGE_SHIFT);
 182 #else /* CONFIG_X86_64 */
 183         end_pfn = ((pos + (PMD_SIZE - 1)) >> PMD_SHIFT)
 184                         << (PMD_SHIFT - PAGE_SHIFT);
 185 #endif
 186         if (end_pfn > (end >> PAGE_SHIFT))
 187                 end_pfn = end >> PAGE_SHIFT;
 188         if (start_pfn < end_pfn) {
 189                 nr_range = save_mr(mr, nr_range, start_pfn, end_pfn, 0);
 190                 pos = end_pfn << PAGE_SHIFT;
 191         }
 192
 193         /* big page (2M) range */
 194         start_pfn = ((pos + (PMD_SIZE - 1))>>PMD_SHIFT)
 195                          << (PMD_SHIFT - PAGE_SHIFT);
 196 #ifdef CONFIG_X86_32
 197         end_pfn = (end>>PMD_SHIFT) << (PMD_SHIFT - PAGE_SHIFT);
 198 #else /* CONFIG_X86_64 */
 199         end_pfn = ((pos + (PUD_SIZE - 1))>>PUD_SHIFT)
 200                          << (PUD_SHIFT - PAGE_SHIFT);
 201         if (end_pfn > ((end>>PMD_SHIFT)<<(PMD_SHIFT - PAGE_SHIFT)))
 202                 end_pfn = ((end>>PMD_SHIFT)<<(PMD_SHIFT - PAGE_SHIFT));
 203 #endif
 204
 205         if (start_pfn < end_pfn) {
 206                 nr_range = save_mr(mr, nr_range, start_pfn, end_pfn,
 207                                 page_size_mask & (1<<PG_LEVEL_2M));
 208                 pos = end_pfn << PAGE_SHIFT;
 209         }
 210
 211 #ifdef CONFIG_X86_64
 212         /* big page (1G) range */
 213         start_pfn = ((pos + (PUD_SIZE - 1))>>PUD_SHIFT)
 214                          << (PUD_SHIFT - PAGE_SHIFT);
 215         end_pfn = (end >> PUD_SHIFT) << (PUD_SHIFT - PAGE_SHIFT);
 216         if (start_pfn < end_pfn) {
 217                 nr_range = save_mr(mr, nr_range, start_pfn, end_pfn,
 218                                 page_size_mask &
 219                                  ((1<<PG_LEVEL_2M)|(1<<PG_LEVEL_1G)));
 220                 pos = end_pfn << PAGE_SHIFT;
 221         }
 222
 223         /* tail is not big page (1G) alignment */
 224         start_pfn = ((pos + (PMD_SIZE - 1))>>PMD_SHIFT)
 225                          << (PMD_SHIFT - PAGE_SHIFT);
 226         end_pfn = (end >> PMD_SHIFT) << (PMD_SHIFT - PAGE_SHIFT);
 227         if (start_pfn < end_pfn) {
 228                 nr_range = save_mr(mr, nr_range, start_pfn, end_pfn,
 229                                 page_size_mask & (1<<PG_LEVEL_2M));
 230                 pos = end_pfn << PAGE_SHIFT;
 231         }
 232 #endif
 233
 234         /* tail is not big page (2M) alignment */
 235         start_pfn = pos>>PAGE_SHIFT;
 236         end_pfn = end>>PAGE_SHIFT;
 237         nr_range = save_mr(mr, nr_range, start_pfn, end_pfn, 0);
 238
 239         /* try to merge same page size and continuous */
 240         for (i = 0; nr_range > 1 && i < nr_range - 1; i++) {
 241                 unsigned long old_start;
 242                 if (mr[i].end != mr[i+1].start ||
 243                     mr[i].page_size_mask != mr[i+1].page_size_mask)
 244                         continue;
 245                 /* move it */
 246                 old_start = mr[i].start;
 247                 memmove(&mr[i], &mr[i+1],
 248                         (nr_range - 1 - i) * sizeof(struct map_range));
 249                 mr[i--].start = old_start;
 250                 nr_range--;
 251         }
 252
 253         for (i = 0; i < nr_range; i++)
 254                 printk(KERN_DEBUG " %010lx - %010lx page %s\n",
 255                                 mr[i].start, mr[i].end,
 256                         (mr[i].page_size_mask & (1<<PG_LEVEL_1G))?"1G":(
 257                          (mr[i].page_size_mask & (1<<PG_LEVEL_2M))?"2M":"4k"));
 258
 259         /*
 260          * Find space for the kernel direct mapping tables.
 261          *
 262          * Later we should allocate these tables in the local node of the
 263          * memory mapped. Unfortunately this is done currently before the
 264          * nodes are discovered.
 265          */
 266         if (!after_bootmem)
 267                 find_early_table_space(end, use_pse, use_gbpages);
 268
 269 #ifdef CONFIG_X86_32
 270         for (i = 0; i < nr_range; i++)
 271                 kernel_physical_mapping_init(mr[i].start, mr[i].end,
 272                                              mr[i].page_size_mask);
 273         ret = end;
 274 #else /* CONFIG_X86_64 */
 275         for (i = 0; i < nr_range; i++)
 276                 ret = kernel_physical_mapping_init(mr[i].start, mr[i].end,
 277                                                    mr[i].page_size_mask);
 278 #endif
 279
 280 #ifdef CONFIG_X86_32
 281         early_ioremap_page_table_range_init();
 282
 283         load_cr3(swapper_pg_dir);
 284 #endif
 285
 286 #ifdef CONFIG_X86_64
 287         if (!after_bootmem && !start) {
 288                 pud_t *pud;
 289                 pmd_t *pmd;
 290
 291                 mmu_cr4_features = read_cr4();
 292
 293                 /*
 294                  * _brk_end cannot change anymore, but it and _end may be
 295                  * located on different 2M pages. cleanup_highmap(), however,
 296                  * can only consider _end when it runs, so destroy any
 297                  * mappings beyond _brk_end here.
 298                  */
 299                 pud = pud_offset(pgd_offset_k(_brk_end), _brk_end);
 300                 pmd = pmd_offset(pud, _brk_end - 1);
 301                 while (++pmd <= pmd_offset(pud, (unsigned long)_end - 1))
 302                         pmd_clear(pmd);
 303         }
 304 #endif
 305         __flush_tlb_all();
 306
 307         if (!after_bootmem && e820_table_end > e820_table_start)
 308                 reserve_early(e820_table_start << PAGE_SHIFT,
 309                                  e820_table_end << PAGE_SHIFT, "PGTABLE");
 310
 311         if (!after_bootmem)
 312                 early_memtest(start, end);
 313
 314         return ret >> PAGE_SHIFT;
 315 }
 316
 317
 318 /*
 319  * devmem_is_allowed() checks to see if /dev/mem access to a certain address
 320  * is valid. The argument is a physical page number.
 321  *
 322  *
 323  * On x86, access has to be given to the first megabyte of ram because that area
 324  * contains bios code and data regions used by X and dosemu and similar apps.
 325  * Access has to be given to non-kernel-ram areas as well, these contain the PCI
 326  * mmio resources as well as potential bios/acpi data regions.
 327  */
 328 int devmem_is_allowed(unsigned long pagenr)
 329 {
 330         if (pagenr <= 256)
 331                 return 1;
 332         if (iomem_is_exclusive(pagenr << PAGE_SHIFT))
 333                 return 0;
 334         if (!page_is_ram(pagenr))
 335                 return 1;
 336         return 0;
 337 }
 338
 339 void free_init_pages(char *what, unsigned long begin, unsigned long end)
 340 {
 341         unsigned long addr = begin;
 342
 343         if (addr >= end)
 344                 return;
 345
 346         /*
 347          * If debugging page accesses then do not free this memory but
 348          * mark them not present - any buggy init-section access will
 349          * create a kernel page fault:
 350          */
 351 #ifdef CONFIG_DEBUG_PAGEALLOC
 352         printk(KERN_INFO "debug: unmapping init memory %08lx..%08lx\n",
 353                 begin, PAGE_ALIGN(end));
 354         set_memory_np(begin, (end - begin) >> PAGE_SHIFT);
 355 #else
 356         /*
 357          * We just marked the kernel text read only above, now that
 358          * we are going to free part of that, we need to make that
 359          * writeable first.
 360          */
 361         set_memory_rw(begin, (end - begin) >> PAGE_SHIFT);
 362
 363         printk(KERN_INFO "Freeing %s: %luk freed\n", what, (end - begin) >> 10);
 364
 365         for (; addr < end; addr += PAGE_SIZE) {
 366                 ClearPageReserved(virt_to_page(addr));
 367                 init_page_count(virt_to_page(addr));
 368                 memset((void *)(addr & ~(PAGE_SIZE-1)),
 369                         POISON_FREE_INITMEM, PAGE_SIZE);
 370                 free_page(addr);
 371                 totalram_pages++;
 372         }
 373 #endif
 374 }
 375
 376 void free_initmem(void)
 377 {
 378         free_init_pages("unused kernel memory",
 379                         (unsigned long)(&__init_begin),
 380                         (unsigned long)(&__init_end));
 381 }
 382
 383 #ifdef CONFIG_BLK_DEV_INITRD
 384 void free_initrd_mem(unsigned long start, unsigned long end)
 385 {
 386         free_init_pages("initrd memory", start, end);
 387 }
 388 #endif