arch/x86/mm/init_32.c

   1 /*
   2  *
   3  *  Copyright (C) 1995  Linus Torvalds
   4  *
   5  *  Support of BIGMEM added by Gerhard Wichert, Siemens AG, July 1999
   6  */
   7
   8 #include <linux/module.h>
   9 #include <linux/signal.h>
  10 #include <linux/sched.h>
  11 #include <linux/kernel.h>
  12 #include <linux/errno.h>
  13 #include <linux/string.h>
  14 #include <linux/types.h>
  15 #include <linux/ptrace.h>
  16 #include <linux/mman.h>
  17 #include <linux/mm.h>
  18 #include <linux/hugetlb.h>
  19 #include <linux/swap.h>
  20 #include <linux/smp.h>
  21 #include <linux/init.h>
  22 #include <linux/highmem.h>
  23 #include <linux/pagemap.h>
  24 #include <linux/pfn.h>
  25 #include <linux/poison.h>
  26 #include <linux/bootmem.h>
  27 #include <linux/slab.h>
  28 #include <linux/proc_fs.h>
  29 #include <linux/memory_hotplug.h>
  30 #include <linux/initrd.h>
  31 #include <linux/cpumask.h>
  32
  33 #include <asm/asm.h>
  34 #include <asm/processor.h>
  35 #include <asm/system.h>
  36 #include <asm/uaccess.h>
  37 #include <asm/pgtable.h>
  38 #include <asm/dma.h>
  39 #include <asm/fixmap.h>
  40 #include <asm/e820.h>
  41 #include <asm/apic.h>
  42 #include <asm/bugs.h>
  43 #include <asm/tlb.h>
  44 #include <asm/tlbflush.h>
  45 #include <asm/pgalloc.h>
  46 #include <asm/sections.h>
  47 #include <asm/paravirt.h>
  48 #include <asm/setup.h>
  49 #include <asm/cacheflush.h>
  50 #include <asm/smp.h>
  51
  52 unsigned int __VMALLOC_RESERVE = 128 << 20;
  53
  54 unsigned long max_low_pfn_mapped;
  55 unsigned long max_pfn_mapped;
  56
  57 DEFINE_PER_CPU(struct mmu_gather, mmu_gathers);
  58 unsigned long highstart_pfn, highend_pfn;
  59
  60 static noinline int do_test_wp_bit(void);
  61
  62
  63 static unsigned long __initdata table_start;
  64 static unsigned long __meminitdata table_end;
  65 static unsigned long __meminitdata table_top;
  66
  67 static int __initdata after_init_bootmem;
  68
  69 static __init void *alloc_low_page(unsigned long *phys)
  70 {
  71         unsigned long pfn = table_end++;
  72         void *adr;
  73
  74         if (pfn >= table_top)
  75                 panic("alloc_low_page: ran out of memory");
  76
  77         adr = __va(pfn * PAGE_SIZE);
  78         memset(adr, 0, PAGE_SIZE);
  79         *phys  = pfn * PAGE_SIZE;
  80         return adr;
  81 }
  82
  83 /*
  84  * Creates a middle page table and puts a pointer to it in the
  85  * given global directory entry. This only returns the gd entry
  86  * in non-PAE compilation mode, since the middle layer is folded.
  87  */
  88 static pmd_t * __init one_md_table_init(pgd_t *pgd)
  89 {
  90         pud_t *pud;
  91         pmd_t *pmd_table;
  92
  93 #ifdef CONFIG_X86_PAE
  94         unsigned long phys;
  95         if (!(pgd_val(*pgd) & _PAGE_PRESENT)) {
  96                 if (after_init_bootmem)
  97                         pmd_table = (pmd_t *)alloc_bootmem_low_pages(PAGE_SIZE);
  98                 else
  99                         pmd_table = (pmd_t *)alloc_low_page(&phys);
 100                 paravirt_alloc_pmd(&init_mm, __pa(pmd_table) >> PAGE_SHIFT);
 101                 set_pgd(pgd, __pgd(__pa(pmd_table) | _PAGE_PRESENT));
 102                 pud = pud_offset(pgd, 0);
 103                 BUG_ON(pmd_table != pmd_offset(pud, 0));
 104         }
 105 #endif
 106         pud = pud_offset(pgd, 0);
 107         pmd_table = pmd_offset(pud, 0);
 108
 109         return pmd_table;
 110 }
 111
 112 /*
 113  * Create a page table and place a pointer to it in a middle page
 114  * directory entry:
 115  */
 116 static pte_t * __init one_page_table_init(pmd_t *pmd)
 117 {
 118         if (!(pmd_val(*pmd) & _PAGE_PRESENT)) {
 119                 pte_t *page_table = NULL;
 120
 121                 if (after_init_bootmem) {
 122 #ifdef CONFIG_DEBUG_PAGEALLOC
 123                         page_table = (pte_t *) alloc_bootmem_pages(PAGE_SIZE);
 124 #endif
 125                         if (!page_table)
 126                                 page_table =
 127                                 (pte_t *)alloc_bootmem_low_pages(PAGE_SIZE);
 128                 } else {
 129                         unsigned long phys;
 130                         page_table = (pte_t *)alloc_low_page(&phys);
 131                 }
 132
 133                 paravirt_alloc_pte(&init_mm, __pa(page_table) >> PAGE_SHIFT);
 134                 set_pmd(pmd, __pmd(__pa(page_table) | _PAGE_TABLE));
 135                 BUG_ON(page_table != pte_offset_kernel(pmd, 0));
 136         }
 137
 138         return pte_offset_kernel(pmd, 0);
 139 }
 140
 141 /*
 142  * This function initializes a certain range of kernel virtual memory
 143  * with new bootmem page tables, everywhere page tables are missing in
 144  * the given range.
 145  *
 146  * NOTE: The pagetables are allocated contiguous on the physical space
 147  * so we can cache the place of the first one and move around without
 148  * checking the pgd every time.
 149  */
 150 static void __init
 151 page_table_range_init(unsigned long start, unsigned long end, pgd_t *pgd_base)
 152 {
 153         int pgd_idx, pmd_idx;
 154         unsigned long vaddr;
 155         pgd_t *pgd;
 156         pmd_t *pmd;
 157
 158         vaddr = start;
 159         pgd_idx = pgd_index(vaddr);
 160         pmd_idx = pmd_index(vaddr);
 161         pgd = pgd_base + pgd_idx;
 162
 163         for ( ; (pgd_idx < PTRS_PER_PGD) && (vaddr != end); pgd++, pgd_idx++) {
 164                 pmd = one_md_table_init(pgd);
 165                 pmd = pmd + pmd_index(vaddr);
 166                 for (; (pmd_idx < PTRS_PER_PMD) && (vaddr != end);
 167                                                         pmd++, pmd_idx++) {
 168                         one_page_table_init(pmd);
 169
 170                         vaddr += PMD_SIZE;
 171                 }
 172                 pmd_idx = 0;
 173         }
 174 }
 175
 176 static inline int is_kernel_text(unsigned long addr)
 177 {
 178         if (addr >= PAGE_OFFSET && addr <= (unsigned long)__init_end)
 179                 return 1;
 180         return 0;
 181 }
 182
 183 /*
 184  * This maps the physical memory to kernel virtual address space, a total
 185  * of max_low_pfn pages, by creating page tables starting from address
 186  * PAGE_OFFSET:
 187  */
 188 static void __init kernel_physical_mapping_init(pgd_t *pgd_base,
 189                                                 unsigned long start_pfn,
 190                                                 unsigned long end_pfn,
 191                                                 int use_pse)
 192 {
 193         int pgd_idx, pmd_idx, pte_ofs;
 194         unsigned long pfn;
 195         pgd_t *pgd;
 196         pmd_t *pmd;
 197         pte_t *pte;
 198         unsigned pages_2m = 0, pages_4k = 0;
 199
 200         if (!cpu_has_pse)
 201                 use_pse = 0;
 202
 203         pfn = start_pfn;
 204         pgd_idx = pgd_index((pfn<<PAGE_SHIFT) + PAGE_OFFSET);
 205         pgd = pgd_base + pgd_idx;
 206         for (; pgd_idx < PTRS_PER_PGD; pgd++, pgd_idx++) {
 207                 pmd = one_md_table_init(pgd);
 208
 209                 if (pfn >= end_pfn)
 210                         continue;
 211 #ifdef CONFIG_X86_PAE
 212                 pmd_idx = pmd_index((pfn<<PAGE_SHIFT) + PAGE_OFFSET);
 213                 pmd += pmd_idx;
 214 #else
 215                 pmd_idx = 0;
 216 #endif
 217                 for (; pmd_idx < PTRS_PER_PMD && pfn < end_pfn;
 218                      pmd++, pmd_idx++) {
 219                         unsigned int addr = pfn * PAGE_SIZE + PAGE_OFFSET;
 220
 221                         /*
 222                          * Map with big pages if possible, otherwise
 223                          * create normal page tables:
 224                          */
 225                         if (use_pse) {
 226                                 unsigned int addr2;
 227                                 pgprot_t prot = PAGE_KERNEL_LARGE;
 228
 229                                 addr2 = (pfn + PTRS_PER_PTE-1) * PAGE_SIZE +
 230                                         PAGE_OFFSET + PAGE_SIZE-1;
 231
 232                                 if (is_kernel_text(addr) ||
 233                                     is_kernel_text(addr2))
 234                                         prot = PAGE_KERNEL_LARGE_EXEC;
 235
 236                                 pages_2m++;
 237                                 set_pmd(pmd, pfn_pmd(pfn, prot));
 238
 239                                 pfn += PTRS_PER_PTE;
 240                                 continue;
 241                         }
 242                         pte = one_page_table_init(pmd);
 243
 244                         pte_ofs = pte_index((pfn<<PAGE_SHIFT) + PAGE_OFFSET);
 245                         pte += pte_ofs;
 246                         for (; pte_ofs < PTRS_PER_PTE && pfn < end_pfn;
 247                              pte++, pfn++, pte_ofs++, addr += PAGE_SIZE) {
 248                                 pgprot_t prot = PAGE_KERNEL;
 249
 250                                 if (is_kernel_text(addr))
 251                                         prot = PAGE_KERNEL_EXEC;
 252
 253                                 pages_4k++;
 254                                 set_pte(pte, pfn_pte(pfn, prot));
 255                         }
 256                 }
 257         }
 258         update_page_count(PG_LEVEL_2M, pages_2m);
 259         update_page_count(PG_LEVEL_4K, pages_4k);
 260 }
 261
 262 /*
 263  * devmem_is_allowed() checks to see if /dev/mem access to a certain address
 264  * is valid. The argument is a physical page number.
 265  *
 266  *
 267  * On x86, access has to be given to the first megabyte of ram because that area
 268  * contains bios code and data regions used by X and dosemu and similar apps.
 269  * Access has to be given to non-kernel-ram areas as well, these contain the PCI
 270  * mmio resources as well as potential bios/acpi data regions.
 271  */
 272 int devmem_is_allowed(unsigned long pagenr)
 273 {
 274         if (pagenr <= 256)
 275                 return 1;
 276         if (!page_is_ram(pagenr))
 277                 return 1;
 278         return 0;
 279 }
 280
 281 #ifdef CONFIG_HIGHMEM
 282 pte_t *kmap_pte;
 283 pgprot_t kmap_prot;
 284
 285 static inline pte_t *kmap_get_fixmap_pte(unsigned long vaddr)
 286 {
 287         return pte_offset_kernel(pmd_offset(pud_offset(pgd_offset_k(vaddr),
 288                         vaddr), vaddr), vaddr);
 289 }
 290
 291 static void __init kmap_init(void)
 292 {
 293         unsigned long kmap_vstart;
 294
 295         /*
 296          * Cache the first kmap pte:
 297          */
 298         kmap_vstart = __fix_to_virt(FIX_KMAP_BEGIN);
 299         kmap_pte = kmap_get_fixmap_pte(kmap_vstart);
 300
 301         kmap_prot = PAGE_KERNEL;
 302 }
 303
 304 static void __init permanent_kmaps_init(pgd_t *pgd_base)
 305 {
 306         unsigned long vaddr;
 307         pgd_t *pgd;
 308         pud_t *pud;
 309         pmd_t *pmd;
 310         pte_t *pte;
 311
 312         vaddr = PKMAP_BASE;
 313         page_table_range_init(vaddr, vaddr + PAGE_SIZE*LAST_PKMAP, pgd_base);
 314
 315         pgd = swapper_pg_dir + pgd_index(vaddr);
 316         pud = pud_offset(pgd, vaddr);
 317         pmd = pmd_offset(pud, vaddr);
 318         pte = pte_offset_kernel(pmd, vaddr);
 319         pkmap_page_table = pte;
 320 }
 321
 322 static void __init add_one_highpage_init(struct page *page, int pfn)
 323 {
 324         ClearPageReserved(page);
 325         init_page_count(page);
 326         __free_page(page);
 327         totalhigh_pages++;
 328 }
 329
 330 struct add_highpages_data {
 331         unsigned long start_pfn;
 332         unsigned long end_pfn;
 333 };
 334
 335 static int __init add_highpages_work_fn(unsigned long start_pfn,
 336                                          unsigned long end_pfn, void *datax)
 337 {
 338         int node_pfn;
 339         struct page *page;
 340         unsigned long final_start_pfn, final_end_pfn;
 341         struct add_highpages_data *data;
 342
 343         data = (struct add_highpages_data *)datax;
 344
 345         final_start_pfn = max(start_pfn, data->start_pfn);
 346         final_end_pfn = min(end_pfn, data->end_pfn);
 347         if (final_start_pfn >= final_end_pfn)
 348                 return 0;
 349
 350         for (node_pfn = final_start_pfn; node_pfn < final_end_pfn;
 351              node_pfn++) {
 352                 if (!pfn_valid(node_pfn))
 353                         continue;
 354                 page = pfn_to_page(node_pfn);
 355                 add_one_highpage_init(page, node_pfn);
 356         }
 357
 358         return 0;
 359
 360 }
 361
 362 void __init add_highpages_with_active_regions(int nid, unsigned long start_pfn,
 363                                               unsigned long end_pfn)
 364 {
 365         struct add_highpages_data data;
 366
 367         data.start_pfn = start_pfn;
 368         data.end_pfn = end_pfn;
 369
 370         work_with_active_regions(nid, add_highpages_work_fn, &data);
 371 }
 372
 373 #ifndef CONFIG_NUMA
 374 static void __init set_highmem_pages_init(void)
 375 {
 376         add_highpages_with_active_regions(0, highstart_pfn, highend_pfn);
 377
 378         totalram_pages += totalhigh_pages;
 379 }
 380 #endif /* !CONFIG_NUMA */
 381
 382 #else
 383 # define kmap_init()                            do { } while (0)
 384 # define permanent_kmaps_init(pgd_base)         do { } while (0)
 385 # define set_highmem_pages_init()       do { } while (0)
 386 #endif /* CONFIG_HIGHMEM */
 387
 388 void __init native_pagetable_setup_start(pgd_t *base)
 389 {
 390         unsigned long pfn, va;
 391         pgd_t *pgd;
 392         pud_t *pud;
 393         pmd_t *pmd;
 394         pte_t *pte;
 395
 396         /*
 397          * Remove any mappings which extend past the end of physical
 398          * memory from the boot time page table:
 399          */
 400         for (pfn = max_low_pfn + 1; pfn < 1<<(32-PAGE_SHIFT); pfn++) {
 401                 va = PAGE_OFFSET + (pfn<<PAGE_SHIFT);
 402                 pgd = base + pgd_index(va);
 403                 if (!pgd_present(*pgd))
 404                         break;
 405
 406                 pud = pud_offset(pgd, va);
 407                 pmd = pmd_offset(pud, va);
 408                 if (!pmd_present(*pmd))
 409                         break;
 410
 411                 pte = pte_offset_kernel(pmd, va);
 412                 if (!pte_present(*pte))
 413                         break;
 414
 415                 pte_clear(NULL, va, pte);
 416         }
 417         paravirt_alloc_pmd(&init_mm, __pa(base) >> PAGE_SHIFT);
 418 }
 419
 420 void __init native_pagetable_setup_done(pgd_t *base)
 421 {
 422 }
 423
 424 /*
 425  * Build a proper pagetable for the kernel mappings.  Up until this
 426  * point, we've been running on some set of pagetables constructed by
 427  * the boot process.
 428  *
 429  * If we're booting on native hardware, this will be a pagetable
 430  * constructed in arch/x86/kernel/head_32.S.  The root of the
 431  * pagetable will be swapper_pg_dir.
 432  *
 433  * If we're booting paravirtualized under a hypervisor, then there are
 434  * more options: we may already be running PAE, and the pagetable may
 435  * or may not be based in swapper_pg_dir.  In any case,
 436  * paravirt_pagetable_setup_start() will set up swapper_pg_dir
 437  * appropriately for the rest of the initialization to work.
 438  *
 439  * In general, pagetable_init() assumes that the pagetable may already
 440  * be partially populated, and so it avoids stomping on any existing
 441  * mappings.
 442  */
 443 static void __init early_ioremap_page_table_range_init(pgd_t *pgd_base)
 444 {
 445         unsigned long vaddr, end;
 446
 447         /*
 448          * Fixed mappings, only the page table structure has to be
 449          * created - mappings will be set by set_fixmap():
 450          */
 451         early_ioremap_clear();
 452         vaddr = __fix_to_virt(__end_of_fixed_addresses - 1) & PMD_MASK;
 453         end = (FIXADDR_TOP + PMD_SIZE - 1) & PMD_MASK;
 454         page_table_range_init(vaddr, end, pgd_base);
 455         early_ioremap_reset();
 456 }
 457
 458 static void __init pagetable_init(void)
 459 {
 460         pgd_t *pgd_base = swapper_pg_dir;
 461
 462         permanent_kmaps_init(pgd_base);
 463 }
 464
 465 #ifdef CONFIG_ACPI_SLEEP
 466 /*
 467  * ACPI suspend needs this for resume, because things like the intel-agp
 468  * driver might have split up a kernel 4MB mapping.
 469  */
 470 char swsusp_pg_dir[PAGE_SIZE]
 471         __attribute__ ((aligned(PAGE_SIZE)));
 472
 473 static inline void save_pg_dir(void)
 474 {
 475         memcpy(swsusp_pg_dir, swapper_pg_dir, PAGE_SIZE);
 476 }
 477 #else /* !CONFIG_ACPI_SLEEP */
 478 static inline void save_pg_dir(void)
 479 {
 480 }
 481 #endif /* !CONFIG_ACPI_SLEEP */
 482
 483 void zap_low_mappings(void)
 484 {
 485         int i;
 486
 487         /*
 488          * Zap initial low-memory mappings.
 489          *
 490          * Note that "pgd_clear()" doesn't do it for
 491          * us, because pgd_clear() is a no-op on i386.
 492          */
 493         for (i = 0; i < KERNEL_PGD_BOUNDARY; i++) {
 494 #ifdef CONFIG_X86_PAE
 495                 set_pgd(swapper_pg_dir+i, __pgd(1 + __pa(empty_zero_page)));
 496 #else
 497                 set_pgd(swapper_pg_dir+i, __pgd(0));
 498 #endif
 499         }
 500         flush_tlb_all();
 501 }
 502
 503 int nx_enabled;
 504
 505 pteval_t __supported_pte_mask __read_mostly = ~(_PAGE_NX | _PAGE_GLOBAL);
 506 EXPORT_SYMBOL_GPL(__supported_pte_mask);
 507
 508 #ifdef CONFIG_X86_PAE
 509
 510 static int disable_nx __initdata;
 511
 512 /*
 513  * noexec = on|off
 514  *
 515  * Control non executable mappings.
 516  *
 517  * on      Enable
 518  * off     Disable
 519  */
 520 static int __init noexec_setup(char *str)
 521 {
 522         if (!str || !strcmp(str, "on")) {
 523                 if (cpu_has_nx) {
 524                         __supported_pte_mask |= _PAGE_NX;
 525                         disable_nx = 0;
 526                 }
 527         } else {
 528                 if (!strcmp(str, "off")) {
 529                         disable_nx = 1;
 530                         __supported_pte_mask &= ~_PAGE_NX;
 531                 } else {
 532                         return -EINVAL;
 533                 }
 534         }
 535
 536         return 0;
 537 }
 538 early_param("noexec", noexec_setup);
 539
 540 static void __init set_nx(void)
 541 {
 542         unsigned int v[4], l, h;
 543
 544         if (cpu_has_pae && (cpuid_eax(0x80000000) > 0x80000001)) {
 545                 cpuid(0x80000001, &v[0], &v[1], &v[2], &v[3]);
 546
 547                 if ((v[3] & (1 << 20)) && !disable_nx) {
 548                         rdmsr(MSR_EFER, l, h);
 549                         l |= EFER_NX;
 550                         wrmsr(MSR_EFER, l, h);
 551                         nx_enabled = 1;
 552                         __supported_pte_mask |= _PAGE_NX;
 553                 }
 554         }
 555 }
 556 #endif
 557
 558 /* user-defined highmem size */
 559 static unsigned int highmem_pages = -1;
 560
 561 /*
 562  * highmem=size forces highmem to be exactly 'size' bytes.
 563  * This works even on boxes that have no highmem otherwise.
 564  * This also works to reduce highmem size on bigger boxes.
 565  */
 566 static int __init parse_highmem(char *arg)
 567 {
 568         if (!arg)
 569                 return -EINVAL;
 570
 571         highmem_pages = memparse(arg, &arg) >> PAGE_SHIFT;
 572         return 0;
 573 }
 574 early_param("highmem", parse_highmem);
 575
 576 /*
 577  * Determine low and high memory ranges:
 578  */
 579 void __init find_low_pfn_range(void)
 580 {
 581         /* it could update max_pfn */
 582
 583         /* max_low_pfn is 0, we already have early_res support */
 584
 585         max_low_pfn = max_pfn;
 586         if (max_low_pfn > MAXMEM_PFN) {
 587                 if (highmem_pages == -1)
 588                         highmem_pages = max_pfn - MAXMEM_PFN;
 589                 if (highmem_pages + MAXMEM_PFN < max_pfn)
 590                         max_pfn = MAXMEM_PFN + highmem_pages;
 591                 if (highmem_pages + MAXMEM_PFN > max_pfn) {
 592                         printk(KERN_WARNING "only %luMB highmem pages "
 593                                 "available, ignoring highmem size of %uMB.\n",
 594                                 pages_to_mb(max_pfn - MAXMEM_PFN),
 595                                 pages_to_mb(highmem_pages));
 596                         highmem_pages = 0;
 597                 }
 598                 max_low_pfn = MAXMEM_PFN;
 599 #ifndef CONFIG_HIGHMEM
 600                 /* Maximum memory usable is what is directly addressable */
 601                 printk(KERN_WARNING "Warning only %ldMB will be used.\n",
 602                                         MAXMEM>>20);
 603                 if (max_pfn > MAX_NONPAE_PFN)
 604                         printk(KERN_WARNING
 605                                  "Use a HIGHMEM64G enabled kernel.\n");
 606                 else
 607                         printk(KERN_WARNING "Use a HIGHMEM enabled kernel.\n");
 608                 max_pfn = MAXMEM_PFN;
 609 #else /* !CONFIG_HIGHMEM */
 610 #ifndef CONFIG_HIGHMEM64G
 611                 if (max_pfn > MAX_NONPAE_PFN) {
 612                         max_pfn = MAX_NONPAE_PFN;
 613                         printk(KERN_WARNING "Warning only 4GB will be used."
 614                                 "Use a HIGHMEM64G enabled kernel.\n");
 615                 }
 616 #endif /* !CONFIG_HIGHMEM64G */
 617 #endif /* !CONFIG_HIGHMEM */
 618         } else {
 619                 if (highmem_pages == -1)
 620                         highmem_pages = 0;
 621 #ifdef CONFIG_HIGHMEM
 622                 if (highmem_pages >= max_pfn) {
 623                         printk(KERN_ERR "highmem size specified (%uMB) is "
 624                                 "bigger than pages available (%luMB)!.\n",
 625                                 pages_to_mb(highmem_pages),
 626                                 pages_to_mb(max_pfn));
 627                         highmem_pages = 0;
 628                 }
 629                 if (highmem_pages) {
 630                         if (max_low_pfn - highmem_pages <
 631                             64*1024*1024/PAGE_SIZE){
 632                                 printk(KERN_ERR "highmem size %uMB results in "
 633                                 "smaller than 64MB lowmem, ignoring it.\n"
 634                                         , pages_to_mb(highmem_pages));
 635                                 highmem_pages = 0;
 636                         }
 637                         max_low_pfn -= highmem_pages;
 638                 }
 639 #else
 640                 if (highmem_pages)
 641                         printk(KERN_ERR "ignoring highmem size on non-highmem"
 642                                         " kernel!\n");
 643 #endif
 644         }
 645 }
 646
 647 #ifndef CONFIG_NEED_MULTIPLE_NODES
 648 void __init initmem_init(unsigned long start_pfn,
 649                                   unsigned long end_pfn)
 650 {
 651 #ifdef CONFIG_HIGHMEM
 652         highstart_pfn = highend_pfn = max_pfn;
 653         if (max_pfn > max_low_pfn)
 654                 highstart_pfn = max_low_pfn;
 655         memory_present(0, 0, highend_pfn);
 656         e820_register_active_regions(0, 0, highend_pfn);
 657         printk(KERN_NOTICE "%ldMB HIGHMEM available.\n",
 658                 pages_to_mb(highend_pfn - highstart_pfn));
 659         num_physpages = highend_pfn;
 660         high_memory = (void *) __va(highstart_pfn * PAGE_SIZE - 1) + 1;
 661 #else
 662         memory_present(0, 0, max_low_pfn);
 663         e820_register_active_regions(0, 0, max_low_pfn);
 664         num_physpages = max_low_pfn;
 665         high_memory = (void *) __va(max_low_pfn * PAGE_SIZE - 1) + 1;
 666 #endif
 667 #ifdef CONFIG_FLATMEM
 668         max_mapnr = num_physpages;
 669 #endif
 670         printk(KERN_NOTICE "%ldMB LOWMEM available.\n",
 671                         pages_to_mb(max_low_pfn));
 672
 673         setup_bootmem_allocator();
 674 }
 675 #endif /* !CONFIG_NEED_MULTIPLE_NODES */
 676
 677 static void __init zone_sizes_init(void)
 678 {
 679         unsigned long max_zone_pfns[MAX_NR_ZONES];
 680         memset(max_zone_pfns, 0, sizeof(max_zone_pfns));
 681         max_zone_pfns[ZONE_DMA] =
 682                 virt_to_phys((char *)MAX_DMA_ADDRESS) >> PAGE_SHIFT;
 683         max_zone_pfns[ZONE_NORMAL] = max_low_pfn;
 684 #ifdef CONFIG_HIGHMEM
 685         max_zone_pfns[ZONE_HIGHMEM] = highend_pfn;
 686 #endif
 687
 688         free_area_init_nodes(max_zone_pfns);
 689 }
 690
 691 void __init setup_bootmem_allocator(void)
 692 {
 693         int i;
 694         unsigned long bootmap_size, bootmap;
 695         /*
 696          * Initialize the boot-time allocator (with low memory only):
 697          */
 698         bootmap_size = bootmem_bootmap_pages(max_low_pfn)<<PAGE_SHIFT;
 699         bootmap = find_e820_area(min_low_pfn<<PAGE_SHIFT,
 700                                  max_pfn_mapped<<PAGE_SHIFT, bootmap_size,
 701                                  PAGE_SIZE);
 702         if (bootmap == -1L)
 703                 panic("Cannot find bootmem map of size %ld\n", bootmap_size);
 704         reserve_early(bootmap, bootmap + bootmap_size, "BOOTMAP");
 705
 706         /* don't touch min_low_pfn */
 707         bootmap_size = init_bootmem_node(NODE_DATA(0), bootmap >> PAGE_SHIFT,
 708                                          min_low_pfn, max_low_pfn);
 709         printk(KERN_INFO "  mapped low ram: 0 - %08lx\n",
 710                  max_pfn_mapped<<PAGE_SHIFT);
 711         printk(KERN_INFO "  low ram: %08lx - %08lx\n",
 712                  min_low_pfn<<PAGE_SHIFT, max_low_pfn<<PAGE_SHIFT);
 713         printk(KERN_INFO "  bootmap %08lx - %08lx\n",
 714                  bootmap, bootmap + bootmap_size);
 715         for_each_online_node(i)
 716                 free_bootmem_with_active_regions(i, max_low_pfn);
 717         early_res_to_bootmem(0, max_low_pfn<<PAGE_SHIFT);
 718
 719         after_init_bootmem = 1;
 720 }
 721
 722 static void __init find_early_table_space(unsigned long end)
 723 {
 724         unsigned long puds, pmds, ptes, tables, start;
 725
 726         puds = (end + PUD_SIZE - 1) >> PUD_SHIFT;
 727         tables = PAGE_ALIGN(puds * sizeof(pud_t));
 728
 729         pmds = (end + PMD_SIZE - 1) >> PMD_SHIFT;
 730         tables += PAGE_ALIGN(pmds * sizeof(pmd_t));
 731
 732         if (cpu_has_pse) {
 733                 unsigned long extra;
 734
 735                 extra = end - ((end>>PMD_SHIFT) << PMD_SHIFT);
 736                 extra += PMD_SIZE;
 737                 ptes = (extra + PAGE_SIZE - 1) >> PAGE_SHIFT;
 738         } else
 739                 ptes = (end + PAGE_SIZE - 1) >> PAGE_SHIFT;
 740
 741         tables += PAGE_ALIGN(ptes * sizeof(pte_t));
 742
 743         /* for fixmap */
 744         tables += PAGE_SIZE * 2;
 745
 746         /*
 747          * RED-PEN putting page tables only on node 0 could
 748          * cause a hotspot and fill up ZONE_DMA. The page tables
 749          * need roughly 0.5KB per GB.
 750          */
 751         start = 0x7000;
 752         table_start = find_e820_area(start, max_pfn_mapped<<PAGE_SHIFT,
 753                                         tables, PAGE_SIZE);
 754         if (table_start == -1UL)
 755                 panic("Cannot find space for the kernel page tables");
 756
 757         table_start >>= PAGE_SHIFT;
 758         table_end = table_start;
 759         table_top = table_start + (tables>>PAGE_SHIFT);
 760
 761         printk(KERN_DEBUG "kernel direct mapping tables up to %lx @ %lx-%lx\n",
 762                 end, table_start << PAGE_SHIFT,
 763                 (table_start << PAGE_SHIFT) + tables);
 764 }
 765
 766 unsigned long __init_refok init_memory_mapping(unsigned long start,
 767                                                 unsigned long end)
 768 {
 769         pgd_t *pgd_base = swapper_pg_dir;
 770         unsigned long start_pfn, end_pfn;
 771         unsigned long big_page_start;
 772
 773         /*
 774          * Find space for the kernel direct mapping tables.
 775          */
 776         if (!after_init_bootmem)
 777                 find_early_table_space(end);
 778
 779 #ifdef CONFIG_X86_PAE
 780         set_nx();
 781         if (nx_enabled)
 782                 printk(KERN_INFO "NX (Execute Disable) protection: active\n");
 783 #endif
 784
 785         /* Enable PSE if available */
 786         if (cpu_has_pse)
 787                 set_in_cr4(X86_CR4_PSE);
 788
 789         /* Enable PGE if available */
 790         if (cpu_has_pge) {
 791                 set_in_cr4(X86_CR4_PGE);
 792                 __supported_pte_mask |= _PAGE_GLOBAL;
 793         }
 794
 795         /*
 796          * Don't use a large page for the first 2/4MB of memory
 797          * because there are often fixed size MTRRs in there
 798          * and overlapping MTRRs into large pages can cause
 799          * slowdowns.
 800          */
 801         big_page_start = PMD_SIZE;
 802
 803         if (start < big_page_start) {
 804                 start_pfn = start >> PAGE_SHIFT;
 805                 end_pfn = min(big_page_start>>PAGE_SHIFT, end>>PAGE_SHIFT);
 806         } else {
 807                 /* head is not big page alignment ? */
 808                 start_pfn = start >> PAGE_SHIFT;
 809                 end_pfn = ((start + (PMD_SIZE - 1))>>PMD_SHIFT)
 810                                  << (PMD_SHIFT - PAGE_SHIFT);
 811         }
 812         if (start_pfn < end_pfn)
 813                 kernel_physical_mapping_init(pgd_base, start_pfn, end_pfn, 0);
 814
 815         /* big page range */
 816         start_pfn = ((start + (PMD_SIZE - 1))>>PMD_SHIFT)
 817                          << (PMD_SHIFT - PAGE_SHIFT);
 818         if (start_pfn < (big_page_start >> PAGE_SHIFT))
 819                 start_pfn =  big_page_start >> PAGE_SHIFT;
 820         end_pfn = (end>>PMD_SHIFT) << (PMD_SHIFT - PAGE_SHIFT);
 821         if (start_pfn < end_pfn)
 822                 kernel_physical_mapping_init(pgd_base, start_pfn, end_pfn,
 823                                                 cpu_has_pse);
 824
 825         /* tail is not big page alignment ? */
 826         start_pfn = end_pfn;
 827         if (start_pfn > (big_page_start>>PAGE_SHIFT)) {
 828                 end_pfn = end >> PAGE_SHIFT;
 829                 if (start_pfn < end_pfn)
 830                         kernel_physical_mapping_init(pgd_base, start_pfn,
 831                                                          end_pfn, 0);
 832         }
 833
 834         early_ioremap_page_table_range_init(pgd_base);
 835
 836         load_cr3(swapper_pg_dir);
 837
 838         __flush_tlb_all();
 839
 840         if (!after_init_bootmem)
 841                 reserve_early(table_start << PAGE_SHIFT,
 842                                  table_end << PAGE_SHIFT, "PGTABLE");
 843
 844         if (!after_init_bootmem)
 845                 early_memtest(start, end);
 846
 847         return end >> PAGE_SHIFT;
 848 }
 849
 850
 851 /*
 852  * paging_init() sets up the page tables - note that the first 8MB are
 853  * already mapped by head.S.
 854  *
 855  * This routines also unmaps the page at virtual kernel address 0, so
 856  * that we can trap those pesky NULL-reference errors in the kernel.
 857  */
 858 void __init paging_init(void)
 859 {
 860         pagetable_init();
 861
 862         __flush_tlb_all();
 863
 864         kmap_init();
 865
 866         /*
 867          * NOTE: at this point the bootmem allocator is fully available.
 868          */
 869         sparse_init();
 870         zone_sizes_init();
 871 }
 872
 873 /*
 874  * Test if the WP bit works in supervisor mode. It isn't supported on 386's
 875  * and also on some strange 486's. All 586+'s are OK. This used to involve
 876  * black magic jumps to work around some nasty CPU bugs, but fortunately the
 877  * switch to using exceptions got rid of all that.
 878  */
 879 static void __init test_wp_bit(void)
 880 {
 881         printk(KERN_INFO
 882   "Checking if this processor honours the WP bit even in supervisor mode...");
 883
 884         /* Any page-aligned address will do, the test is non-destructive */
 885         __set_fixmap(FIX_WP_TEST, __pa(&swapper_pg_dir), PAGE_READONLY);
 886         boot_cpu_data.wp_works_ok = do_test_wp_bit();
 887         clear_fixmap(FIX_WP_TEST);
 888
 889         if (!boot_cpu_data.wp_works_ok) {
 890                 printk(KERN_CONT "No.\n");
 891 #ifdef CONFIG_X86_WP_WORKS_OK
 892                 panic(
 893   "This kernel doesn't support CPU's with broken WP. Recompile it for a 386!");
 894 #endif
 895         } else {
 896                 printk(KERN_CONT "Ok.\n");
 897         }
 898 }
 899
 900 static struct kcore_list kcore_mem, kcore_vmalloc;
 901
 902 void __init mem_init(void)
 903 {
 904         int codesize, reservedpages, datasize, initsize;
 905         int tmp;
 906
 907 #ifdef CONFIG_FLATMEM
 908         BUG_ON(!mem_map);
 909 #endif
 910         /* this will put all low memory onto the freelists */
 911         totalram_pages += free_all_bootmem();
 912
 913         reservedpages = 0;
 914         for (tmp = 0; tmp < max_low_pfn; tmp++)
 915                 /*
 916                  * Only count reserved RAM pages:
 917                  */
 918                 if (page_is_ram(tmp) && PageReserved(pfn_to_page(tmp)))
 919                         reservedpages++;
 920
 921         set_highmem_pages_init();
 922
 923         codesize =  (unsigned long) &_etext - (unsigned long) &_text;
 924         datasize =  (unsigned long) &_edata - (unsigned long) &_etext;
 925         initsize =  (unsigned long) &__init_end - (unsigned long) &__init_begin;
 926
 927         kclist_add(&kcore_mem, __va(0), max_low_pfn << PAGE_SHIFT);
 928         kclist_add(&kcore_vmalloc, (void *)VMALLOC_START,
 929                    VMALLOC_END-VMALLOC_START);
 930
 931         printk(KERN_INFO "Memory: %luk/%luk available (%dk kernel code, "
 932                         "%dk reserved, %dk data, %dk init, %ldk highmem)\n",
 933                 (unsigned long) nr_free_pages() << (PAGE_SHIFT-10),
 934                 num_physpages << (PAGE_SHIFT-10),
 935                 codesize >> 10,
 936                 reservedpages << (PAGE_SHIFT-10),
 937                 datasize >> 10,
 938                 initsize >> 10,
 939                 (unsigned long) (totalhigh_pages << (PAGE_SHIFT-10))
 940                );
 941
 942         printk(KERN_INFO "virtual kernel memory layout:\n"
 943                 "    fixmap  : 0x%08lx - 0x%08lx   (%4ld kB)\n"
 944 #ifdef CONFIG_HIGHMEM
 945                 "    pkmap   : 0x%08lx - 0x%08lx   (%4ld kB)\n"
 946 #endif
 947                 "    vmalloc : 0x%08lx - 0x%08lx   (%4ld MB)\n"
 948                 "    lowmem  : 0x%08lx - 0x%08lx   (%4ld MB)\n"
 949                 "      .init : 0x%08lx - 0x%08lx   (%4ld kB)\n"
 950                 "      .data : 0x%08lx - 0x%08lx   (%4ld kB)\n"
 951                 "      .text : 0x%08lx - 0x%08lx   (%4ld kB)\n",
 952                 FIXADDR_START, FIXADDR_TOP,
 953                 (FIXADDR_TOP - FIXADDR_START) >> 10,
 954
 955 #ifdef CONFIG_HIGHMEM
 956                 PKMAP_BASE, PKMAP_BASE+LAST_PKMAP*PAGE_SIZE,
 957                 (LAST_PKMAP*PAGE_SIZE) >> 10,
 958 #endif
 959
 960                 VMALLOC_START, VMALLOC_END,
 961                 (VMALLOC_END - VMALLOC_START) >> 20,
 962
 963                 (unsigned long)__va(0), (unsigned long)high_memory,
 964                 ((unsigned long)high_memory - (unsigned long)__va(0)) >> 20,
 965
 966                 (unsigned long)&__init_begin, (unsigned long)&__init_end,
 967                 ((unsigned long)&__init_end -
 968                  (unsigned long)&__init_begin) >> 10,
 969
 970                 (unsigned long)&_etext, (unsigned long)&_edata,
 971                 ((unsigned long)&_edata - (unsigned long)&_etext) >> 10,
 972
 973                 (unsigned long)&_text, (unsigned long)&_etext,
 974                 ((unsigned long)&_etext - (unsigned long)&_text) >> 10);
 975
 976 #ifdef CONFIG_HIGHMEM
 977         BUG_ON(PKMAP_BASE + LAST_PKMAP*PAGE_SIZE        > FIXADDR_START);
 978         BUG_ON(VMALLOC_END                              > PKMAP_BASE);
 979 #endif
 980         BUG_ON(VMALLOC_START                            > VMALLOC_END);
 981         BUG_ON((unsigned long)high_memory               > VMALLOC_START);
 982
 983         if (boot_cpu_data.wp_works_ok < 0)
 984                 test_wp_bit();
 985
 986         cpa_init();
 987         save_pg_dir();
 988         zap_low_mappings();
 989 }
 990
 991 #ifdef CONFIG_MEMORY_HOTPLUG
 992 int arch_add_memory(int nid, u64 start, u64 size)
 993 {
 994         struct pglist_data *pgdata = NODE_DATA(nid);
 995         struct zone *zone = pgdata->node_zones + ZONE_HIGHMEM;
 996         unsigned long start_pfn = start >> PAGE_SHIFT;
 997         unsigned long nr_pages = size >> PAGE_SHIFT;
 998
 999         return __add_pages(zone, start_pfn, nr_pages);
1000 }
1001 #endif
1002
1003 /*
1004  * This function cannot be __init, since exceptions don't work in that
1005  * section.  Put this after the callers, so that it cannot be inlined.
1006  */
1007 static noinline int do_test_wp_bit(void)
1008 {
1009         char tmp_reg;
1010         int flag;
1011
1012         __asm__ __volatile__(
1013                 "       movb %0, %1     \n"
1014                 "1:     movb %1, %0     \n"
1015                 "       xorl %2, %2     \n"
1016                 "2:                     \n"
1017                 _ASM_EXTABLE(1b,2b)
1018                 :"=m" (*(char *)fix_to_virt(FIX_WP_TEST)),
1019                  "=q" (tmp_reg),
1020                  "=r" (flag)
1021                 :"2" (1)
1022                 :"memory");
1023
1024         return flag;
1025 }
1026
1027 #ifdef CONFIG_DEBUG_RODATA
1028 const int rodata_test_data = 0xC3;
1029 EXPORT_SYMBOL_GPL(rodata_test_data);
1030
1031 void mark_rodata_ro(void)
1032 {
1033         unsigned long start = PFN_ALIGN(_text);
1034         unsigned long size = PFN_ALIGN(_etext) - start;
1035
1036 #ifndef CONFIG_DYNAMIC_FTRACE
1037         /* Dynamic tracing modifies the kernel text section */
1038         set_pages_ro(virt_to_page(start), size >> PAGE_SHIFT);
1039         printk(KERN_INFO "Write protecting the kernel text: %luk\n",
1040                 size >> 10);
1041
1042 #ifdef CONFIG_CPA_DEBUG
1043         printk(KERN_INFO "Testing CPA: Reverting %lx-%lx\n",
1044                 start, start+size);
1045         set_pages_rw(virt_to_page(start), size>>PAGE_SHIFT);
1046
1047         printk(KERN_INFO "Testing CPA: write protecting again\n");
1048         set_pages_ro(virt_to_page(start), size>>PAGE_SHIFT);
1049 #endif
1050 #endif /* CONFIG_DYNAMIC_FTRACE */
1051
1052         start += size;
1053         size = (unsigned long)__end_rodata - start;
1054         set_pages_ro(virt_to_page(start), size >> PAGE_SHIFT);
1055         printk(KERN_INFO "Write protecting the kernel read-only data: %luk\n",
1056                 size >> 10);
1057         rodata_test();
1058
1059 #ifdef CONFIG_CPA_DEBUG
1060         printk(KERN_INFO "Testing CPA: undo %lx-%lx\n", start, start + size);
1061         set_pages_rw(virt_to_page(start), size >> PAGE_SHIFT);
1062
1063         printk(KERN_INFO "Testing CPA: write protecting again\n");
1064         set_pages_ro(virt_to_page(start), size >> PAGE_SHIFT);
1065 #endif
1066 }
1067 #endif
1068
1069 void free_init_pages(char *what, unsigned long begin, unsigned long end)
1070 {
1071 #ifdef CONFIG_DEBUG_PAGEALLOC
1072         /*
1073          * If debugging page accesses then do not free this memory but
1074          * mark them not present - any buggy init-section access will
1075          * create a kernel page fault:
1076          */
1077         printk(KERN_INFO "debug: unmapping init memory %08lx..%08lx\n",
1078                 begin, PAGE_ALIGN(end));
1079         set_memory_np(begin, (end - begin) >> PAGE_SHIFT);
1080 #else
1081         unsigned long addr;
1082
1083         /*
1084          * We just marked the kernel text read only above, now that
1085          * we are going to free part of that, we need to make that
1086          * writeable first.
1087          */
1088         set_memory_rw(begin, (end - begin) >> PAGE_SHIFT);
1089
1090         for (addr = begin; addr < end; addr += PAGE_SIZE) {
1091                 ClearPageReserved(virt_to_page(addr));
1092                 init_page_count(virt_to_page(addr));
1093                 memset((void *)addr, POISON_FREE_INITMEM, PAGE_SIZE);
1094                 free_page(addr);
1095                 totalram_pages++;
1096         }
1097         printk(KERN_INFO "Freeing %s: %luk freed\n", what, (end - begin) >> 10);
1098 #endif
1099 }
1100
1101 void free_initmem(void)
1102 {
1103         free_init_pages("unused kernel memory",
1104                         (unsigned long)(&__init_begin),
1105                         (unsigned long)(&__init_end));
1106 }
1107
1108 #ifdef CONFIG_BLK_DEV_INITRD
1109 void free_initrd_mem(unsigned long start, unsigned long end)
1110 {
1111         free_init_pages("initrd memory", start, end);
1112 }
1113 #endif
1114
1115 int __init reserve_bootmem_generic(unsigned long phys, unsigned long len,
1116                                    int flags)
1117 {
1118         return reserve_bootmem(phys, len, flags);
1119 }