LXR linux/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
  17DEFINE_PER_CPU(struct mmu_gather, mmu_gathers);
  18
  19unsigned long __initdata e820_table_start;
  20unsigned long __meminitdata e820_table_end;
  21unsigned long __meminitdata e820_table_top;
  22
  23int after_bootmem;
  24
  25int direct_gbpages
  26#ifdef CONFIG_DIRECT_GBPAGES
  27                                = 1
  28#endif
  29;
  30
  31static 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
  90struct 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
 102static 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 */
 123unsigned 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 */
 332int 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
 343void 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
 380void 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
 388void free_initrd_mem(unsigned long start, unsigned long end)
 389{
 390        free_init_pages("initrd memory", start, end);
 391}
 392#endif
 393