release/src-rt-6.x.4708/linux/linux-2.6.36/arch/x86/mm/init.c

   1 #include <linux/gfp.h>
   2 #include <linux/initrd.h>
   3 #include <linux/ioport.h>
   4 #include <linux/swap.h>
   5
   6 #include <asm/cacheflush.h>
   7 #include <asm/e820.h>
   8 #include <asm/init.h>
   9 #include <asm/page.h>
  10 #include <asm/page_types.h>
  11 #include <asm/sections.h>
  12 #include <asm/setup.h>
  13 #include <asm/system.h>
  14 #include <asm/tlbflush.h>
  15 #include <asm/tlb.h>
  16 #include <asm/proto.h>
  17
  18 DEFINE_PER_CPU(struct mmu_gather, mmu_gathers);
  19
  20 unsigned long __initdata e820_table_start;
  21 unsigned long __meminitdata e820_table_end;
  22 unsigned long __meminitdata e820_table_top;
  23
  24 int after_bootmem;
  25
  26 int direct_gbpages
  27 #ifdef CONFIG_DIRECT_GBPAGES
  28                                 = 1
  29 #endif
  30 ;
  31
  32 static void __init find_early_table_space(unsigned long end, int use_pse,
  33                                           int use_gbpages)
  34 {
  35         unsigned long puds, pmds, ptes, tables, start;
  36
  37         puds = (end + PUD_SIZE - 1) >> PUD_SHIFT;
  38         tables = roundup(puds * sizeof(pud_t), PAGE_SIZE);
  39
  40         if (use_gbpages) {
  41                 unsigned long extra;
  42
  43                 extra = end - ((end>>PUD_SHIFT) << PUD_SHIFT);
  44                 pmds = (extra + PMD_SIZE - 1) >> PMD_SHIFT;
  45         } else
  46                 pmds = (end + PMD_SIZE - 1) >> PMD_SHIFT;
  47
  48         tables += roundup(pmds * sizeof(pmd_t), PAGE_SIZE);
  49
  50         if (use_pse) {
  51                 unsigned long extra;
  52
  53                 extra = end - ((end>>PMD_SHIFT) << PMD_SHIFT);
  54 #ifdef CONFIG_X86_32
  55                 extra += PMD_SIZE;
  56 #endif
  57                 ptes = (extra + PAGE_SIZE - 1) >> PAGE_SHIFT;
  58         } else
  59                 ptes = (end + PAGE_SIZE - 1) >> PAGE_SHIFT;
  60
  61         tables += roundup(ptes * sizeof(pte_t), PAGE_SIZE);
  62
  63 #ifdef CONFIG_X86_32
  64         /* for fixmap */
  65         tables += roundup(__end_of_fixed_addresses * sizeof(pte_t), PAGE_SIZE);
  66 #endif
  67
  68         /*
  69          * RED-PEN putting page tables only on node 0 could
  70          * cause a hotspot and fill up ZONE_DMA. The page tables
  71          * need roughly 0.5KB per GB.
  72          */
  73 #ifdef CONFIG_X86_32
  74         start = 0x7000;
  75 #else
  76         start = 0x8000;
  77 #endif
  78         e820_table_start = find_e820_area(start, max_pfn_mapped<<PAGE_SHIFT,
  79                                         tables, PAGE_SIZE);
  80         if (e820_table_start == -1UL)
  81                 panic("Cannot find space for the kernel page tables");
  82
  83         e820_table_start >>= PAGE_SHIFT;
  84         e820_table_end = e820_table_start;
  85         e820_table_top = e820_table_start + (tables >> PAGE_SHIFT);
  86
  87         printk(KERN_DEBUG "kernel direct mapping tables up to %lx @ %lx-%lx\n",
  88                 end, e820_table_start << PAGE_SHIFT, e820_table_top << PAGE_SHIFT);
  89 }
  90
  91 struct map_range {
  92         unsigned long start;
  93         unsigned long end;
  94         unsigned page_size_mask;
  95 };
  96
  97 #ifdef CONFIG_X86_32
  98 #define NR_RANGE_MR 3
  99 #else /* CONFIG_X86_64 */
 100 #define NR_RANGE_MR 5
 101 #endif
 102
 103 static int __meminit save_mr(struct map_range *mr, int nr_range,
 104                              unsigned long start_pfn, unsigned long end_pfn,
 105                              unsigned long page_size_mask)
 106 {
 107         if (start_pfn < end_pfn) {
 108                 if (nr_range >= NR_RANGE_MR)
 109                         panic("run out of range for init_memory_mapping\n");
 110                 mr[nr_range].start = start_pfn<<PAGE_SHIFT;
 111                 mr[nr_range].end   = end_pfn<<PAGE_SHIFT;
 112                 mr[nr_range].page_size_mask = page_size_mask;
 113                 nr_range++;
 114         }
 115
 116         return nr_range;
 117 }
 118
 119 /*
 120  * Setup the direct mapping of the physical memory at PAGE_OFFSET.
 121  * This runs before bootmem is initialized and gets pages directly from
 122  * the physical memory. To access them they are temporarily mapped.
 123  */
 124 unsigned long __init_refok init_memory_mapping(unsigned long start,
 125                                                unsigned long end)
 126 {
 127         unsigned long page_size_mask = 0;
 128         unsigned long start_pfn, end_pfn;
 129         unsigned long ret = 0;
 130         unsigned long pos;
 131
 132         struct map_range mr[NR_RANGE_MR];
 133         int nr_range, i;
 134         int use_pse, use_gbpages;
 135
 136         printk(KERN_INFO "init_memory_mapping: %016lx-%016lx\n", start, end);
 137
 138 #if defined(CONFIG_DEBUG_PAGEALLOC) || defined(CONFIG_KMEMCHECK)
 139         /*
 140          * For CONFIG_DEBUG_PAGEALLOC, identity mapping will use small pages.
 141          * This will simplify cpa(), which otherwise needs to support splitting
 142          * large pages into small in interrupt context, etc.
 143          */
 144         use_pse = use_gbpages = 0;
 145 #else
 146         use_pse = cpu_has_pse;
 147         use_gbpages = direct_gbpages;
 148 #endif
 149
 150         /* Enable PSE if available */
 151         if (cpu_has_pse)
 152                 set_in_cr4(X86_CR4_PSE);
 153
 154         /* Enable PGE if available */
 155         if (cpu_has_pge) {
 156                 set_in_cr4(X86_CR4_PGE);
 157                 __supported_pte_mask |= _PAGE_GLOBAL;
 158         }
 159
 160         if (use_gbpages)
 161                 page_size_mask |= 1 << PG_LEVEL_1G;
 162         if (use_pse)
 163                 page_size_mask |= 1 << PG_LEVEL_2M;
 164
 165         memset(mr, 0, sizeof(mr));
 166         nr_range = 0;
 167
 168         /* head if not big page alignment ? */
 169         start_pfn = start >> PAGE_SHIFT;
 170         pos = start_pfn << PAGE_SHIFT;
 171 #ifdef CONFIG_X86_32
 172         /*
 173          * Don't use a large page for the first 2/4MB of memory
 174          * because there are often fixed size MTRRs in there
 175          * and overlapping MTRRs into large pages can cause
 176          * slowdowns.
 177          */
 178         if (pos == 0)
 179                 end_pfn = 1<<(PMD_SHIFT - PAGE_SHIFT);
 180         else
 181                 end_pfn = ((pos + (PMD_SIZE - 1))>>PMD_SHIFT)
 182                                  << (PMD_SHIFT - PAGE_SHIFT);
 183 #else /* CONFIG_X86_64 */
 184         end_pfn = ((pos + (PMD_SIZE - 1)) >> PMD_SHIFT)
 185                         << (PMD_SHIFT - PAGE_SHIFT);
 186 #endif
 187         if (end_pfn > (end >> PAGE_SHIFT))
 188                 end_pfn = end >> PAGE_SHIFT;
 189         if (start_pfn < end_pfn) {
 190                 nr_range = save_mr(mr, nr_range, start_pfn, end_pfn, 0);
 191                 pos = end_pfn << PAGE_SHIFT;
 192         }
 193
 194         /* big page (2M) range */
 195         start_pfn = ((pos + (PMD_SIZE - 1))>>PMD_SHIFT)
 196                          << (PMD_SHIFT - PAGE_SHIFT);
 197 #ifdef CONFIG_X86_32
 198         end_pfn = (end>>PMD_SHIFT) << (PMD_SHIFT - PAGE_SHIFT);
 199 #else /* CONFIG_X86_64 */
 200         end_pfn = ((pos + (PUD_SIZE - 1))>>PUD_SHIFT)
 201                          << (PUD_SHIFT - PAGE_SHIFT);
 202         if (end_pfn > ((end>>PMD_SHIFT)<<(PMD_SHIFT - PAGE_SHIFT)))
 203                 end_pfn = ((end>>PMD_SHIFT)<<(PMD_SHIFT - PAGE_SHIFT));
 204 #endif
 205
 206         if (start_pfn < end_pfn) {
 207                 nr_range = save_mr(mr, nr_range, start_pfn, end_pfn,
 208                                 page_size_mask & (1<<PG_LEVEL_2M));
 209                 pos = end_pfn << PAGE_SHIFT;
 210         }
 211
 212 #ifdef CONFIG_X86_64
 213         /* big page (1G) range */
 214         start_pfn = ((pos + (PUD_SIZE - 1))>>PUD_SHIFT)
 215                          << (PUD_SHIFT - PAGE_SHIFT);
 216         end_pfn = (end >> PUD_SHIFT) << (PUD_SHIFT - PAGE_SHIFT);
 217         if (start_pfn < end_pfn) {
 218                 nr_range = save_mr(mr, nr_range, start_pfn, end_pfn,
 219                                 page_size_mask &
 220                                  ((1<<PG_LEVEL_2M)|(1<<PG_LEVEL_1G)));
 221                 pos = end_pfn << PAGE_SHIFT;
 222         }
 223
 224         /* tail is not big page (1G) alignment */
 225         start_pfn = ((pos + (PMD_SIZE - 1))>>PMD_SHIFT)
 226                          << (PMD_SHIFT - PAGE_SHIFT);
 227         end_pfn = (end >> PMD_SHIFT) << (PMD_SHIFT - PAGE_SHIFT);
 228         if (start_pfn < end_pfn) {
 229                 nr_range = save_mr(mr, nr_range, start_pfn, end_pfn,
 230                                 page_size_mask & (1<<PG_LEVEL_2M));
 231                 pos = end_pfn << PAGE_SHIFT;
 232         }
 233 #endif
 234
 235         /* tail is not big page (2M) alignment */
 236         start_pfn = pos>>PAGE_SHIFT;
 237         end_pfn = end>>PAGE_SHIFT;
 238         nr_range = save_mr(mr, nr_range, start_pfn, end_pfn, 0);
 239
 240         /* try to merge same page size and continuous */
 241         for (i = 0; nr_range > 1 && i < nr_range - 1; i++) {
 242                 unsigned long old_start;
 243                 if (mr[i].end != mr[i+1].start ||
 244                     mr[i].page_size_mask != mr[i+1].page_size_mask)
 245                         continue;
 246                 /* move it */
 247                 old_start = mr[i].start;
 248                 memmove(&mr[i], &mr[i+1],
 249                         (nr_range - 1 - i) * sizeof(struct map_range));
 250                 mr[i--].start = old_start;
 251                 nr_range--;
 252         }
 253
 254         for (i = 0; i < nr_range; i++)
 255                 printk(KERN_DEBUG " %010lx - %010lx page %s\n",
 256                                 mr[i].start, mr[i].end,
 257                         (mr[i].page_size_mask & (1<<PG_LEVEL_1G))?"1G":(
 258                          (mr[i].page_size_mask & (1<<PG_LEVEL_2M))?"2M":"4k"));
 259
 260         /*
 261          * Find space for the kernel direct mapping tables.
 262          *
 263          * Later we should allocate these tables in the local node of the
 264          * memory mapped. Unfortunately this is done currently before the
 265          * nodes are discovered.
 266          */
 267         if (!after_bootmem)
 268                 find_early_table_space(end, use_pse, use_gbpages);
 269
 270         for (i = 0; i < nr_range; i++)
 271                 ret = kernel_physical_mapping_init(mr[i].start, mr[i].end,
 272                                                    mr[i].page_size_mask);
 273
 274 #ifdef CONFIG_X86_32
 275         early_ioremap_page_table_range_init();
 276
 277         load_cr3(swapper_pg_dir);
 278 #endif
 279
 280 #ifdef CONFIG_X86_64
 281         if (!after_bootmem && !start) {
 282                 pud_t *pud;
 283                 pmd_t *pmd;
 284
 285                 mmu_cr4_features = read_cr4();
 286
 287                 /*
 288                  * _brk_end cannot change anymore, but it and _end may be
 289                  * located on different 2M pages. cleanup_highmap(), however,
 290                  * can only consider _end when it runs, so destroy any
 291                  * mappings beyond _brk_end here.
 292                  */
 293                 pud = pud_offset(pgd_offset_k(_brk_end), _brk_end);
 294                 pmd = pmd_offset(pud, _brk_end - 1);
 295                 while (++pmd <= pmd_offset(pud, (unsigned long)_end - 1))
 296                         pmd_clear(pmd);
 297         }
 298 #endif
 299         __flush_tlb_all();
 300
 301         if (!after_bootmem && e820_table_end > e820_table_start)
 302                 reserve_early(e820_table_start << PAGE_SHIFT,
 303                                  e820_table_end << PAGE_SHIFT, "PGTABLE");
 304
 305         if (!after_bootmem)
 306                 early_memtest(start, end);
 307
 308         return ret >> PAGE_SHIFT;
 309 }
 310
 311
 312 /*
 313  * devmem_is_allowed() checks to see if /dev/mem access to a certain address
 314  * is valid. The argument is a physical page number.
 315  *
 316  *
 317  * On x86, access has to be given to the first megabyte of ram because that area
 318  * contains bios code and data regions used by X and dosemu and similar apps.
 319  * Access has to be given to non-kernel-ram areas as well, these contain the PCI
 320  * mmio resources as well as potential bios/acpi data regions.
 321  */
 322 int devmem_is_allowed(unsigned long pagenr)
 323 {
 324         if (pagenr <= 256)
 325                 return 1;
 326         if (iomem_is_exclusive(pagenr << PAGE_SHIFT))
 327                 return 0;
 328         if (!page_is_ram(pagenr))
 329                 return 1;
 330         return 0;
 331 }
 332
 333 void free_init_pages(char *what, unsigned long begin, unsigned long end)
 334 {
 335         unsigned long addr;
 336         unsigned long begin_aligned, end_aligned;
 337
 338         /* Make sure boundaries are page aligned */
 339         begin_aligned = PAGE_ALIGN(begin);
 340         end_aligned   = end & PAGE_MASK;
 341
 342         if (WARN_ON(begin_aligned != begin || end_aligned != end)) {
 343                 begin = begin_aligned;
 344                 end   = end_aligned;
 345         }
 346
 347         if (begin >= end)
 348                 return;
 349
 350         addr = begin;
 351
 352         /*
 353          * If debugging page accesses then do not free this memory but
 354          * mark them not present - any buggy init-section access will
 355          * create a kernel page fault:
 356          */
 357 #ifdef CONFIG_DEBUG_PAGEALLOC
 358         printk(KERN_INFO "debug: unmapping init memory %08lx..%08lx\n",
 359                 begin, end);
 360         set_memory_np(begin, (end - begin) >> PAGE_SHIFT);
 361 #else
 362         /*
 363          * We just marked the kernel text read only above, now that
 364          * we are going to free part of that, we need to make that
 365          * writeable first.
 366          */
 367         set_memory_rw(begin, (end - begin) >> PAGE_SHIFT);
 368
 369         printk(KERN_INFO "Freeing %s: %luk freed\n", what, (end - begin) >> 10);
 370
 371         for (; addr < end; addr += PAGE_SIZE) {
 372                 ClearPageReserved(virt_to_page(addr));
 373                 init_page_count(virt_to_page(addr));
 374                 memset((void *)addr, POISON_FREE_INITMEM, PAGE_SIZE);
 375                 free_page(addr);
 376                 totalram_pages++;
 377         }
 378 #endif
 379 }
 380
 381 void free_initmem(void)
 382 {
 383         free_init_pages("unused kernel memory",
 384                         (unsigned long)(&__init_begin),
 385                         (unsigned long)(&__init_end));
 386 }
 387
 388 #ifdef CONFIG_BLK_DEV_INITRD
 389 void free_initrd_mem(unsigned long start, unsigned long end)
 390 {
 391         /*
 392          * end could be not aligned, and We can not align that,
 393          * decompresser could be confused by aligned initrd_end
 394          * We already reserve the end partial page before in
 395          *   - i386_start_kernel()
 396          *   - x86_64_start_kernel()
 397          *   - relocate_initrd()
 398          * So here We can do PAGE_ALIGN() safely to get partial page to be freed
 399          */
 400         free_init_pages("initrd memory", start, PAGE_ALIGN(end));
 401 }
 402 #endif