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 #include <linux/memblock.h>
   6
   7 #include <asm/cacheflush.h>
   8 #include <asm/e820.h>
   9 #include <asm/init.h>
  10 #include <asm/page.h>
  11 #include <asm/page_types.h>
  12 #include <asm/sections.h>
  13 #include <asm/setup.h>
  14 #include <asm/system.h>
  15 #include <asm/tlbflush.h>
  16 #include <asm/tlb.h>
  17 #include <asm/proto.h>
  18
  19 DEFINE_PER_CPU(struct mmu_gather, mmu_gathers);
  20
  21 unsigned long __initdata pgt_buf_start;
  22 unsigned long __meminitdata pgt_buf_end;
  23 unsigned long __meminitdata pgt_buf_top;
  24
  25 int after_bootmem;
  26
  27 int direct_gbpages
  28 #ifdef CONFIG_DIRECT_GBPAGES
  29                                 = 1
  30 #endif
  31 ;
  32
  33 static void __init find_early_table_space(unsigned long end, int use_pse,
  34                                           int use_gbpages)
  35 {
  36         unsigned long puds, pmds, ptes, tables, start = 0, good_end = end;
  37         phys_addr_t base;
  38
  39         puds = (end + PUD_SIZE - 1) >> PUD_SHIFT;
  40         tables = roundup(puds * sizeof(pud_t), PAGE_SIZE);
  41
  42         if (use_gbpages) {
  43                 unsigned long extra;
  44
  45                 extra = end - ((end>>PUD_SHIFT) << PUD_SHIFT);
  46                 pmds = (extra + PMD_SIZE - 1) >> PMD_SHIFT;
  47         } else
  48                 pmds = (end + PMD_SIZE - 1) >> PMD_SHIFT;
  49
  50         tables += roundup(pmds * sizeof(pmd_t), PAGE_SIZE);
  51
  52         if (use_pse) {
  53                 unsigned long extra;
  54
  55                 extra = end - ((end>>PMD_SHIFT) << PMD_SHIFT);
  56 #ifdef CONFIG_X86_32
  57                 extra += PMD_SIZE;
  58 #endif
  59                 ptes = (extra + PAGE_SIZE - 1) >> PAGE_SHIFT;
  60         } else
  61                 ptes = (end + PAGE_SIZE - 1) >> PAGE_SHIFT;
  62
  63         tables += roundup(ptes * sizeof(pte_t), PAGE_SIZE);
  64
  65 #ifdef CONFIG_X86_32
  66         /* for fixmap */
  67         tables += roundup(__end_of_fixed_addresses * sizeof(pte_t), PAGE_SIZE);
  68
  69         good_end = max_pfn_mapped << PAGE_SHIFT;
  70 #endif
  71
  72         base = memblock_find_in_range(start, good_end, tables, PAGE_SIZE);
  73         if (base == MEMBLOCK_ERROR)
  74                 panic("Cannot find space for the kernel page tables");
  75
  76         pgt_buf_start = base >> PAGE_SHIFT;
  77         pgt_buf_end = pgt_buf_start;
  78         pgt_buf_top = pgt_buf_start + (tables >> PAGE_SHIFT);
  79
  80         printk(KERN_DEBUG "kernel direct mapping tables up to %lx @ %lx-%lx\n",
  81                 end, pgt_buf_start << PAGE_SHIFT, pgt_buf_top << PAGE_SHIFT);
  82 }
  83
  84 struct map_range {
  85         unsigned long start;
  86         unsigned long end;
  87         unsigned page_size_mask;
  88 };
  89
  90 #ifdef CONFIG_X86_32
  91 #define NR_RANGE_MR 3
  92 #else /* CONFIG_X86_64 */
  93 #define NR_RANGE_MR 5
  94 #endif
  95
  96 static int __meminit save_mr(struct map_range *mr, int nr_range,
  97                              unsigned long start_pfn, unsigned long end_pfn,
  98                              unsigned long page_size_mask)
  99 {
 100         if (start_pfn < end_pfn) {
 101                 if (nr_range >= NR_RANGE_MR)
 102                         panic("run out of range for init_memory_mapping\n");
 103                 mr[nr_range].start = start_pfn<<PAGE_SHIFT;
 104                 mr[nr_range].end   = end_pfn<<PAGE_SHIFT;
 105                 mr[nr_range].page_size_mask = page_size_mask;
 106                 nr_range++;
 107         }
 108
 109         return nr_range;
 110 }
 111
 112 /*
 113  * Setup the direct mapping of the physical memory at PAGE_OFFSET.
 114  * This runs before bootmem is initialized and gets pages directly from
 115  * the physical memory. To access them they are temporarily mapped.
 116  */
 117 unsigned long __init_refok init_memory_mapping(unsigned long start,
 118                                                unsigned long end)
 119 {
 120         unsigned long page_size_mask = 0;
 121         unsigned long start_pfn, end_pfn;
 122         unsigned long ret = 0;
 123         unsigned long pos;
 124
 125         struct map_range mr[NR_RANGE_MR];
 126         int nr_range, i;
 127         int use_pse, use_gbpages;
 128
 129         printk(KERN_INFO "init_memory_mapping: %016lx-%016lx\n", start, end);
 130
 131 #if defined(CONFIG_DEBUG_PAGEALLOC) || defined(CONFIG_KMEMCHECK)
 132         /*
 133          * For CONFIG_DEBUG_PAGEALLOC, identity mapping will use small pages.
 134          * This will simplify cpa(), which otherwise needs to support splitting
 135          * large pages into small in interrupt context, etc.
 136          */
 137         use_pse = use_gbpages = 0;
 138 #else
 139         use_pse = cpu_has_pse;
 140         use_gbpages = direct_gbpages;
 141 #endif
 142
 143         /* Enable PSE if available */
 144         if (cpu_has_pse)
 145                 set_in_cr4(X86_CR4_PSE);
 146
 147         /* Enable PGE if available */
 148         if (cpu_has_pge) {
 149                 set_in_cr4(X86_CR4_PGE);
 150                 __supported_pte_mask |= _PAGE_GLOBAL;
 151         }
 152
 153         if (use_gbpages)
 154                 page_size_mask |= 1 << PG_LEVEL_1G;
 155         if (use_pse)
 156                 page_size_mask |= 1 << PG_LEVEL_2M;
 157
 158         memset(mr, 0, sizeof(mr));
 159         nr_range = 0;
 160
 161         /* head if not big page alignment ? */
 162         start_pfn = start >> PAGE_SHIFT;
 163         pos = start_pfn << PAGE_SHIFT;
 164 #ifdef CONFIG_X86_32
 165         /*
 166          * Don't use a large page for the first 2/4MB of memory
 167          * because there are often fixed size MTRRs in there
 168          * and overlapping MTRRs into large pages can cause
 169          * slowdowns.
 170          */
 171         if (pos == 0)
 172                 end_pfn = 1<<(PMD_SHIFT - PAGE_SHIFT);
 173         else
 174                 end_pfn = ((pos + (PMD_SIZE - 1))>>PMD_SHIFT)
 175                                  << (PMD_SHIFT - PAGE_SHIFT);
 176 #else /* CONFIG_X86_64 */
 177         end_pfn = ((pos + (PMD_SIZE - 1)) >> PMD_SHIFT)
 178                         << (PMD_SHIFT - PAGE_SHIFT);
 179 #endif
 180         if (end_pfn > (end >> PAGE_SHIFT))
 181                 end_pfn = end >> PAGE_SHIFT;
 182         if (start_pfn < end_pfn) {
 183                 nr_range = save_mr(mr, nr_range, start_pfn, end_pfn, 0);
 184                 pos = end_pfn << PAGE_SHIFT;
 185         }
 186
 187         /* big page (2M) range */
 188         start_pfn = ((pos + (PMD_SIZE - 1))>>PMD_SHIFT)
 189                          << (PMD_SHIFT - PAGE_SHIFT);
 190 #ifdef CONFIG_X86_32
 191         end_pfn = (end>>PMD_SHIFT) << (PMD_SHIFT - PAGE_SHIFT);
 192 #else /* CONFIG_X86_64 */
 193         end_pfn = ((pos + (PUD_SIZE - 1))>>PUD_SHIFT)
 194                          << (PUD_SHIFT - PAGE_SHIFT);
 195         if (end_pfn > ((end>>PMD_SHIFT)<<(PMD_SHIFT - PAGE_SHIFT)))
 196                 end_pfn = ((end>>PMD_SHIFT)<<(PMD_SHIFT - PAGE_SHIFT));
 197 #endif
 198
 199         if (start_pfn < end_pfn) {
 200                 nr_range = save_mr(mr, nr_range, start_pfn, end_pfn,
 201                                 page_size_mask & (1<<PG_LEVEL_2M));
 202                 pos = end_pfn << PAGE_SHIFT;
 203         }
 204
 205 #ifdef CONFIG_X86_64
 206         /* big page (1G) range */
 207         start_pfn = ((pos + (PUD_SIZE - 1))>>PUD_SHIFT)
 208                          << (PUD_SHIFT - PAGE_SHIFT);
 209         end_pfn = (end >> PUD_SHIFT) << (PUD_SHIFT - PAGE_SHIFT);
 210         if (start_pfn < end_pfn) {
 211                 nr_range = save_mr(mr, nr_range, start_pfn, end_pfn,
 212                                 page_size_mask &
 213                                  ((1<<PG_LEVEL_2M)|(1<<PG_LEVEL_1G)));
 214                 pos = end_pfn << PAGE_SHIFT;
 215         }
 216
 217         /* tail is not big page (1G) alignment */
 218         start_pfn = ((pos + (PMD_SIZE - 1))>>PMD_SHIFT)
 219                          << (PMD_SHIFT - PAGE_SHIFT);
 220         end_pfn = (end >> PMD_SHIFT) << (PMD_SHIFT - PAGE_SHIFT);
 221         if (start_pfn < end_pfn) {
 222                 nr_range = save_mr(mr, nr_range, start_pfn, end_pfn,
 223                                 page_size_mask & (1<<PG_LEVEL_2M));
 224                 pos = end_pfn << PAGE_SHIFT;
 225         }
 226 #endif
 227
 228         /* tail is not big page (2M) alignment */
 229         start_pfn = pos>>PAGE_SHIFT;
 230         end_pfn = end>>PAGE_SHIFT;
 231         nr_range = save_mr(mr, nr_range, start_pfn, end_pfn, 0);
 232
 233         /* try to merge same page size and continuous */
 234         for (i = 0; nr_range > 1 && i < nr_range - 1; i++) {
 235                 unsigned long old_start;
 236                 if (mr[i].end != mr[i+1].start ||
 237                     mr[i].page_size_mask != mr[i+1].page_size_mask)
 238                         continue;
 239                 /* move it */
 240                 old_start = mr[i].start;
 241                 memmove(&mr[i], &mr[i+1],
 242                         (nr_range - 1 - i) * sizeof(struct map_range));
 243                 mr[i--].start = old_start;
 244                 nr_range--;
 245         }
 246
 247         for (i = 0; i < nr_range; i++)
 248                 printk(KERN_DEBUG " %010lx - %010lx page %s\n",
 249                                 mr[i].start, mr[i].end,
 250                         (mr[i].page_size_mask & (1<<PG_LEVEL_1G))?"1G":(
 251                          (mr[i].page_size_mask & (1<<PG_LEVEL_2M))?"2M":"4k"));
 252
 253         /*
 254          * Find space for the kernel direct mapping tables.
 255          *
 256          * Later we should allocate these tables in the local node of the
 257          * memory mapped. Unfortunately this is done currently before the
 258          * nodes are discovered.
 259          */
 260         if (!after_bootmem)
 261                 find_early_table_space(end, use_pse, use_gbpages);
 262
 263         for (i = 0; i < nr_range; i++)
 264                 ret = kernel_physical_mapping_init(mr[i].start, mr[i].end,
 265                                                    mr[i].page_size_mask);
 266
 267 #ifdef CONFIG_X86_32
 268         early_ioremap_page_table_range_init();
 269
 270         load_cr3(swapper_pg_dir);
 271 #endif
 272
 273         __flush_tlb_all();
 274
 275         if (!after_bootmem && pgt_buf_end > pgt_buf_start)
 276                 memblock_x86_reserve_range(pgt_buf_start << PAGE_SHIFT,
 277                                  pgt_buf_end << PAGE_SHIFT, "PGTABLE");
 278
 279         if (!after_bootmem)
 280                 early_memtest(start, end);
 281
 282         return ret >> PAGE_SHIFT;
 283 }
 284
 285
 286 /*
 287  * devmem_is_allowed() checks to see if /dev/mem access to a certain address
 288  * is valid. The argument is a physical page number.
 289  *
 290  *
 291  * On x86, access has to be given to the first megabyte of ram because that area
 292  * contains bios code and data regions used by X and dosemu and similar apps.
 293  * Access has to be given to non-kernel-ram areas as well, these contain the PCI
 294  * mmio resources as well as potential bios/acpi data regions.
 295  */
 296 int devmem_is_allowed(unsigned long pagenr)
 297 {
 298         if (pagenr <= 256)
 299                 return 1;
 300         if (iomem_is_exclusive(pagenr << PAGE_SHIFT))
 301                 return 0;
 302         if (!page_is_ram(pagenr))
 303                 return 1;
 304         return 0;
 305 }
 306
 307 void free_init_pages(char *what, unsigned long begin, unsigned long end)
 308 {
 309         unsigned long addr;
 310         unsigned long begin_aligned, end_aligned;
 311
 312         /* Make sure boundaries are page aligned */
 313         begin_aligned = PAGE_ALIGN(begin);
 314         end_aligned   = end & PAGE_MASK;
 315
 316         if (WARN_ON(begin_aligned != begin || end_aligned != end)) {
 317                 begin = begin_aligned;
 318                 end   = end_aligned;
 319         }
 320
 321         if (begin >= end)
 322                 return;
 323
 324         addr = begin;
 325
 326         /*
 327          * If debugging page accesses then do not free this memory but
 328          * mark them not present - any buggy init-section access will
 329          * create a kernel page fault:
 330          */
 331 #ifdef CONFIG_DEBUG_PAGEALLOC
 332         printk(KERN_INFO "debug: unmapping init memory %08lx..%08lx\n",
 333                 begin, end);
 334         set_memory_np(begin, (end - begin) >> PAGE_SHIFT);
 335 #else
 336         /*
 337          * We just marked the kernel text read only above, now that
 338          * we are going to free part of that, we need to make that
 339          * writeable and non-executable first.
 340          */
 341         set_memory_nx(begin, (end - begin) >> PAGE_SHIFT);
 342         set_memory_rw(begin, (end - begin) >> PAGE_SHIFT);
 343
 344         printk(KERN_INFO "Freeing %s: %luk freed\n", what, (end - begin) >> 10);
 345
 346         for (; addr < end; addr += PAGE_SIZE) {
 347                 ClearPageReserved(virt_to_page(addr));
 348                 init_page_count(virt_to_page(addr));
 349                 memset((void *)addr, POISON_FREE_INITMEM, PAGE_SIZE);
 350                 free_page(addr);
 351                 totalram_pages++;
 352         }
 353 #endif
 354 }
 355
 356 void free_initmem(void)
 357 {
 358         free_init_pages("unused kernel memory",
 359                         (unsigned long)(&__init_begin),
 360                         (unsigned long)(&__init_end));
 361 }
 362
 363 #ifdef CONFIG_BLK_DEV_INITRD
 364 void free_initrd_mem(unsigned long start, unsigned long end)
 365 {
 366         /*
 367          * end could be not aligned, and We can not align that,
 368          * decompresser could be confused by aligned initrd_end
 369          * We already reserve the end partial page before in
 370          *   - i386_start_kernel()
 371          *   - x86_64_start_kernel()
 372          *   - relocate_initrd()
 373          * So here We can do PAGE_ALIGN() safely to get partial page to be freed
 374          */
 375         free_init_pages("initrd memory", start, PAGE_ALIGN(end));
 376 }
 377 #endif