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/pci.h>
  25 #include <linux/pfn.h>
  26 #include <linux/poison.h>
  27 #include <linux/bootmem.h>
  28 #include <linux/slab.h>
  29 #include <linux/proc_fs.h>
  30 #include <linux/memory_hotplug.h>
  31 #include <linux/initrd.h>
  32 #include <linux/cpumask.h>
  33
  34 #include <asm/asm.h>
  35 #include <asm/bios_ebda.h>
  36 #include <asm/processor.h>
  37 #include <asm/system.h>
  38 #include <asm/uaccess.h>
  39 #include <asm/pgtable.h>
  40 #include <asm/dma.h>
  41 #include <asm/fixmap.h>
  42 #include <asm/e820.h>
  43 #include <asm/apic.h>
  44 #include <asm/bugs.h>
  45 #include <asm/tlb.h>
  46 #include <asm/tlbflush.h>
  47 #include <asm/pgalloc.h>
  48 #include <asm/sections.h>
  49 #include <asm/paravirt.h>
  50 #include <asm/setup.h>
  51 #include <asm/cacheflush.h>
  52 #include <asm/init.h>
  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 bool __read_mostly __vmalloc_start_set = false;
  63
  64 static __init void *alloc_low_page(void)
  65 {
  66         unsigned long pfn = e820_table_end++;
  67         void *adr;
  68
  69         if (pfn >= e820_table_top)
  70                 panic("alloc_low_page: ran out of memory");
  71
  72         adr = __va(pfn * PAGE_SIZE);
  73         memset(adr, 0, PAGE_SIZE);
  74         return adr;
  75 }
  76
  77 /*
  78  * Creates a middle page table and puts a pointer to it in the
  79  * given global directory entry. This only returns the gd entry
  80  * in non-PAE compilation mode, since the middle layer is folded.
  81  */
  82 static pmd_t * __init one_md_table_init(pgd_t *pgd)
  83 {
  84         pud_t *pud;
  85         pmd_t *pmd_table;
  86
  87 #ifdef CONFIG_X86_PAE
  88         if (!(pgd_val(*pgd) & _PAGE_PRESENT)) {
  89                 if (after_bootmem)
  90                         pmd_table = (pmd_t *)alloc_bootmem_low_pages(PAGE_SIZE);
  91                 else
  92                         pmd_table = (pmd_t *)alloc_low_page();
  93                 paravirt_alloc_pmd(&init_mm, __pa(pmd_table) >> PAGE_SHIFT);
  94                 set_pgd(pgd, __pgd(__pa(pmd_table) | _PAGE_PRESENT));
  95                 pud = pud_offset(pgd, 0);
  96                 BUG_ON(pmd_table != pmd_offset(pud, 0));
  97
  98                 return pmd_table;
  99         }
 100 #endif
 101         pud = pud_offset(pgd, 0);
 102         pmd_table = pmd_offset(pud, 0);
 103
 104         return pmd_table;
 105 }
 106
 107 /*
 108  * Create a page table and place a pointer to it in a middle page
 109  * directory entry:
 110  */
 111 static pte_t * __init one_page_table_init(pmd_t *pmd)
 112 {
 113         if (!(pmd_val(*pmd) & _PAGE_PRESENT)) {
 114                 pte_t *page_table = NULL;
 115
 116                 if (after_bootmem) {
 117 #ifdef CONFIG_DEBUG_PAGEALLOC
 118                         page_table = (pte_t *) alloc_bootmem_pages(PAGE_SIZE);
 119 #endif
 120                         if (!page_table)
 121                                 page_table =
 122                                 (pte_t *)alloc_bootmem_low_pages(PAGE_SIZE);
 123                 } else
 124                         page_table = (pte_t *)alloc_low_page();
 125
 126                 paravirt_alloc_pte(&init_mm, __pa(page_table) >> PAGE_SHIFT);
 127                 set_pmd(pmd, __pmd(__pa(page_table) | _PAGE_TABLE));
 128                 BUG_ON(page_table != pte_offset_kernel(pmd, 0));
 129         }
 130
 131         return pte_offset_kernel(pmd, 0);
 132 }
 133
 134 pmd_t * __init populate_extra_pmd(unsigned long vaddr)
 135 {
 136         int pgd_idx = pgd_index(vaddr);
 137         int pmd_idx = pmd_index(vaddr);
 138
 139         return one_md_table_init(swapper_pg_dir + pgd_idx) + pmd_idx;
 140 }
 141
 142 pte_t * __init populate_extra_pte(unsigned long vaddr)
 143 {
 144         int pte_idx = pte_index(vaddr);
 145         pmd_t *pmd;
 146
 147         pmd = populate_extra_pmd(vaddr);
 148         return one_page_table_init(pmd) + pte_idx;
 149 }
 150
 151 static pte_t *__init page_table_kmap_check(pte_t *pte, pmd_t *pmd,
 152                                            unsigned long vaddr, pte_t *lastpte)
 153 {
 154 #ifdef CONFIG_HIGHMEM
 155         /*
 156          * Something (early fixmap) may already have put a pte
 157          * page here, which causes the page table allocation
 158          * to become nonlinear. Attempt to fix it, and if it
 159          * is still nonlinear then we have to bug.
 160          */
 161         int pmd_idx_kmap_begin = fix_to_virt(FIX_KMAP_END) >> PMD_SHIFT;
 162         int pmd_idx_kmap_end = fix_to_virt(FIX_KMAP_BEGIN) >> PMD_SHIFT;
 163
 164         if (pmd_idx_kmap_begin != pmd_idx_kmap_end
 165             && (vaddr >> PMD_SHIFT) >= pmd_idx_kmap_begin
 166             && (vaddr >> PMD_SHIFT) <= pmd_idx_kmap_end
 167             && ((__pa(pte) >> PAGE_SHIFT) < e820_table_start
 168                 || (__pa(pte) >> PAGE_SHIFT) >= e820_table_end)) {
 169                 pte_t *newpte;
 170                 int i;
 171
 172                 BUG_ON(after_bootmem);
 173                 newpte = alloc_low_page();
 174                 for (i = 0; i < PTRS_PER_PTE; i++)
 175                         set_pte(newpte + i, pte[i]);
 176
 177                 paravirt_alloc_pte(&init_mm, __pa(newpte) >> PAGE_SHIFT);
 178                 set_pmd(pmd, __pmd(__pa(newpte)|_PAGE_TABLE));
 179                 BUG_ON(newpte != pte_offset_kernel(pmd, 0));
 180                 __flush_tlb_all();
 181
 182                 paravirt_release_pte(__pa(pte) >> PAGE_SHIFT);
 183                 pte = newpte;
 184         }
 185         BUG_ON(vaddr < fix_to_virt(FIX_KMAP_BEGIN - 1)
 186                && vaddr > fix_to_virt(FIX_KMAP_END)
 187                && lastpte && lastpte + PTRS_PER_PTE != pte);
 188 #endif
 189         return pte;
 190 }
 191
 192 /*
 193  * This function initializes a certain range of kernel virtual memory
 194  * with new bootmem page tables, everywhere page tables are missing in
 195  * the given range.
 196  *
 197  * NOTE: The pagetables are allocated contiguous on the physical space
 198  * so we can cache the place of the first one and move around without
 199  * checking the pgd every time.
 200  */
 201 static void __init
 202 page_table_range_init(unsigned long start, unsigned long end, pgd_t *pgd_base)
 203 {
 204         int pgd_idx, pmd_idx;
 205         unsigned long vaddr;
 206         pgd_t *pgd;
 207         pmd_t *pmd;
 208         pte_t *pte = NULL;
 209
 210         vaddr = start;
 211         pgd_idx = pgd_index(vaddr);
 212         pmd_idx = pmd_index(vaddr);
 213         pgd = pgd_base + pgd_idx;
 214
 215         for ( ; (pgd_idx < PTRS_PER_PGD) && (vaddr != end); pgd++, pgd_idx++) {
 216                 pmd = one_md_table_init(pgd);
 217                 pmd = pmd + pmd_index(vaddr);
 218                 for (; (pmd_idx < PTRS_PER_PMD) && (vaddr != end);
 219                                                         pmd++, pmd_idx++) {
 220                         pte = page_table_kmap_check(one_page_table_init(pmd),
 221                                                     pmd, vaddr, pte);
 222
 223                         vaddr += PMD_SIZE;
 224                 }
 225                 pmd_idx = 0;
 226         }
 227 }
 228
 229 static inline int is_kernel_text(unsigned long addr)
 230 {
 231         if (addr >= PAGE_OFFSET && addr <= (unsigned long)__init_end)
 232                 return 1;
 233         return 0;
 234 }
 235
 236 /*
 237  * This maps the physical memory to kernel virtual address space, a total
 238  * of max_low_pfn pages, by creating page tables starting from address
 239  * PAGE_OFFSET:
 240  */
 241 unsigned long __init
 242 kernel_physical_mapping_init(unsigned long start,
 243                              unsigned long end,
 244                              unsigned long page_size_mask)
 245 {
 246         int use_pse = page_size_mask == (1<<PG_LEVEL_2M);
 247         unsigned long start_pfn, end_pfn;
 248         pgd_t *pgd_base = swapper_pg_dir;
 249         int pgd_idx, pmd_idx, pte_ofs;
 250         unsigned long pfn;
 251         pgd_t *pgd;
 252         pmd_t *pmd;
 253         pte_t *pte;
 254         unsigned pages_2m, pages_4k;
 255         int mapping_iter;
 256
 257         start_pfn = start >> PAGE_SHIFT;
 258         end_pfn = end >> PAGE_SHIFT;
 259
 260         /*
 261          * First iteration will setup identity mapping using large/small pages
 262          * based on use_pse, with other attributes same as set by
 263          * the early code in head_32.S
 264          *
 265          * Second iteration will setup the appropriate attributes (NX, GLOBAL..)
 266          * as desired for the kernel identity mapping.
 267          *
 268          * This two pass mechanism conforms to the TLB app note which says:
 269          *
 270          *     "Software should not write to a paging-structure entry in a way
 271          *      that would change, for any linear address, both the page size
 272          *      and either the page frame or attributes."
 273          */
 274         mapping_iter = 1;
 275
 276         if (!cpu_has_pse)
 277                 use_pse = 0;
 278
 279 repeat:
 280         pages_2m = pages_4k = 0;
 281         pfn = start_pfn;
 282         pgd_idx = pgd_index((pfn<<PAGE_SHIFT) + PAGE_OFFSET);
 283         pgd = pgd_base + pgd_idx;
 284         for (; pgd_idx < PTRS_PER_PGD; pgd++, pgd_idx++) {
 285                 pmd = one_md_table_init(pgd);
 286
 287                 if (pfn >= end_pfn)
 288                         continue;
 289 #ifdef CONFIG_X86_PAE
 290                 pmd_idx = pmd_index((pfn<<PAGE_SHIFT) + PAGE_OFFSET);
 291                 pmd += pmd_idx;
 292 #else
 293                 pmd_idx = 0;
 294 #endif
 295                 for (; pmd_idx < PTRS_PER_PMD && pfn < end_pfn;
 296                      pmd++, pmd_idx++) {
 297                         unsigned int addr = pfn * PAGE_SIZE + PAGE_OFFSET;
 298
 299                         /*
 300                          * Map with big pages if possible, otherwise
 301                          * create normal page tables:
 302                          */
 303                         if (use_pse) {
 304                                 unsigned int addr2;
 305                                 pgprot_t prot = PAGE_KERNEL_LARGE;
 306                                 /*
 307                                  * first pass will use the same initial
 308                                  * identity mapping attribute + _PAGE_PSE.
 309                                  */
 310                                 pgprot_t init_prot =
 311                                         __pgprot(PTE_IDENT_ATTR |
 312                                                  _PAGE_PSE);
 313
 314                                 addr2 = (pfn + PTRS_PER_PTE-1) * PAGE_SIZE +
 315                                         PAGE_OFFSET + PAGE_SIZE-1;
 316
 317                                 if (is_kernel_text(addr) ||
 318                                     is_kernel_text(addr2))
 319                                         prot = PAGE_KERNEL_LARGE_EXEC;
 320
 321                                 pages_2m++;
 322                                 if (mapping_iter == 1)
 323                                         set_pmd(pmd, pfn_pmd(pfn, init_prot));
 324                                 else
 325                                         set_pmd(pmd, pfn_pmd(pfn, prot));
 326
 327                                 pfn += PTRS_PER_PTE;
 328                                 continue;
 329                         }
 330                         pte = one_page_table_init(pmd);
 331
 332                         pte_ofs = pte_index((pfn<<PAGE_SHIFT) + PAGE_OFFSET);
 333                         pte += pte_ofs;
 334                         for (; pte_ofs < PTRS_PER_PTE && pfn < end_pfn;
 335                              pte++, pfn++, pte_ofs++, addr += PAGE_SIZE) {
 336                                 pgprot_t prot = PAGE_KERNEL;
 337                                 /*
 338                                  * first pass will use the same initial
 339                                  * identity mapping attribute.
 340                                  */
 341                                 pgprot_t init_prot = __pgprot(PTE_IDENT_ATTR);
 342
 343                                 if (is_kernel_text(addr))
 344                                         prot = PAGE_KERNEL_EXEC;
 345
 346                                 pages_4k++;
 347                                 if (mapping_iter == 1)
 348                                         set_pte(pte, pfn_pte(pfn, init_prot));
 349                                 else
 350                                         set_pte(pte, pfn_pte(pfn, prot));
 351                         }
 352                 }
 353         }
 354         if (mapping_iter == 1) {
 355                 /*
 356                  * update direct mapping page count only in the first
 357                  * iteration.
 358                  */
 359                 update_page_count(PG_LEVEL_2M, pages_2m);
 360                 update_page_count(PG_LEVEL_4K, pages_4k);
 361
 362                 /*
 363                  * local global flush tlb, which will flush the previous
 364                  * mappings present in both small and large page TLB's.
 365                  */
 366                 __flush_tlb_all();
 367
 368                 /*
 369                  * Second iteration will set the actual desired PTE attributes.
 370                  */
 371                 mapping_iter = 2;
 372                 goto repeat;
 373         }
 374         return 0;
 375 }
 376
 377 pte_t *kmap_pte;
 378 pgprot_t kmap_prot;
 379
 380 static inline pte_t *kmap_get_fixmap_pte(unsigned long vaddr)
 381 {
 382         return pte_offset_kernel(pmd_offset(pud_offset(pgd_offset_k(vaddr),
 383                         vaddr), vaddr), vaddr);
 384 }
 385
 386 static void __init kmap_init(void)
 387 {
 388         unsigned long kmap_vstart;
 389
 390         /*
 391          * Cache the first kmap pte:
 392          */
 393         kmap_vstart = __fix_to_virt(FIX_KMAP_BEGIN);
 394         kmap_pte = kmap_get_fixmap_pte(kmap_vstart);
 395
 396         kmap_prot = PAGE_KERNEL;
 397 }
 398
 399 #ifdef CONFIG_HIGHMEM
 400 static void __init permanent_kmaps_init(pgd_t *pgd_base)
 401 {
 402         unsigned long vaddr;
 403         pgd_t *pgd;
 404         pud_t *pud;
 405         pmd_t *pmd;
 406         pte_t *pte;
 407
 408         vaddr = PKMAP_BASE;
 409         page_table_range_init(vaddr, vaddr + PAGE_SIZE*LAST_PKMAP, pgd_base);
 410
 411         pgd = swapper_pg_dir + pgd_index(vaddr);
 412         pud = pud_offset(pgd, vaddr);
 413         pmd = pmd_offset(pud, vaddr);
 414         pte = pte_offset_kernel(pmd, vaddr);
 415         pkmap_page_table = pte;
 416 }
 417
 418 static void __init add_one_highpage_init(struct page *page, int pfn)
 419 {
 420         ClearPageReserved(page);
 421         init_page_count(page);
 422         __free_page(page);
 423         totalhigh_pages++;
 424 }
 425
 426 struct add_highpages_data {
 427         unsigned long start_pfn;
 428         unsigned long end_pfn;
 429 };
 430
 431 static int __init add_highpages_work_fn(unsigned long start_pfn,
 432                                          unsigned long end_pfn, void *datax)
 433 {
 434         int node_pfn;
 435         struct page *page;
 436         unsigned long final_start_pfn, final_end_pfn;
 437         struct add_highpages_data *data;
 438
 439         data = (struct add_highpages_data *)datax;
 440
 441         final_start_pfn = max(start_pfn, data->start_pfn);
 442         final_end_pfn = min(end_pfn, data->end_pfn);
 443         if (final_start_pfn >= final_end_pfn)
 444                 return 0;
 445
 446         for (node_pfn = final_start_pfn; node_pfn < final_end_pfn;
 447              node_pfn++) {
 448                 if (!pfn_valid(node_pfn))
 449                         continue;
 450                 page = pfn_to_page(node_pfn);
 451                 add_one_highpage_init(page, node_pfn);
 452         }
 453
 454         return 0;
 455
 456 }
 457
 458 void __init add_highpages_with_active_regions(int nid, unsigned long start_pfn,
 459                                               unsigned long end_pfn)
 460 {
 461         struct add_highpages_data data;
 462
 463         data.start_pfn = start_pfn;
 464         data.end_pfn = end_pfn;
 465
 466         work_with_active_regions(nid, add_highpages_work_fn, &data);
 467 }
 468
 469 #else
 470 static inline void permanent_kmaps_init(pgd_t *pgd_base)
 471 {
 472 }
 473 #endif /* CONFIG_HIGHMEM */
 474
 475 void __init native_pagetable_setup_start(pgd_t *base)
 476 {
 477         unsigned long pfn, va;
 478         pgd_t *pgd;
 479         pud_t *pud;
 480         pmd_t *pmd;
 481         pte_t *pte;
 482
 483         /*
 484          * Remove any mappings which extend past the end of physical
 485          * memory from the boot time page table:
 486          */
 487         for (pfn = max_low_pfn + 1; pfn < 1<<(32-PAGE_SHIFT); pfn++) {
 488                 va = PAGE_OFFSET + (pfn<<PAGE_SHIFT);
 489                 pgd = base + pgd_index(va);
 490                 if (!pgd_present(*pgd))
 491                         break;
 492
 493                 pud = pud_offset(pgd, va);
 494                 pmd = pmd_offset(pud, va);
 495                 if (!pmd_present(*pmd))
 496                         break;
 497
 498                 pte = pte_offset_kernel(pmd, va);
 499                 if (!pte_present(*pte))
 500                         break;
 501
 502                 pte_clear(NULL, va, pte);
 503         }
 504         paravirt_alloc_pmd(&init_mm, __pa(base) >> PAGE_SHIFT);
 505 }
 506
 507 void __init native_pagetable_setup_done(pgd_t *base)
 508 {
 509 }
 510
 511 /*
 512  * Build a proper pagetable for the kernel mappings.  Up until this
 513  * point, we've been running on some set of pagetables constructed by
 514  * the boot process.
 515  *
 516  * If we're booting on native hardware, this will be a pagetable
 517  * constructed in arch/x86/kernel/head_32.S.  The root of the
 518  * pagetable will be swapper_pg_dir.
 519  *
 520  * If we're booting paravirtualized under a hypervisor, then there are
 521  * more options: we may already be running PAE, and the pagetable may
 522  * or may not be based in swapper_pg_dir.  In any case,
 523  * paravirt_pagetable_setup_start() will set up swapper_pg_dir
 524  * appropriately for the rest of the initialization to work.
 525  *
 526  * In general, pagetable_init() assumes that the pagetable may already
 527  * be partially populated, and so it avoids stomping on any existing
 528  * mappings.
 529  */
 530 void __init early_ioremap_page_table_range_init(void)
 531 {
 532         pgd_t *pgd_base = swapper_pg_dir;
 533         unsigned long vaddr, end;
 534
 535         /*
 536          * Fixed mappings, only the page table structure has to be
 537          * created - mappings will be set by set_fixmap():
 538          */
 539         vaddr = __fix_to_virt(__end_of_fixed_addresses - 1) & PMD_MASK;
 540         end = (FIXADDR_TOP + PMD_SIZE - 1) & PMD_MASK;
 541         page_table_range_init(vaddr, end, pgd_base);
 542         early_ioremap_reset();
 543 }
 544
 545 static void __init pagetable_init(void)
 546 {
 547         pgd_t *pgd_base = swapper_pg_dir;
 548
 549         permanent_kmaps_init(pgd_base);
 550 }
 551
 552 #ifdef CONFIG_ACPI_SLEEP
 553 /*
 554  * ACPI suspend needs this for resume, because things like the intel-agp
 555  * driver might have split up a kernel 4MB mapping.
 556  */
 557 char swsusp_pg_dir[PAGE_SIZE]
 558         __attribute__ ((aligned(PAGE_SIZE)));
 559
 560 static inline void save_pg_dir(void)
 561 {
 562         memcpy(swsusp_pg_dir, swapper_pg_dir, PAGE_SIZE);
 563 }
 564 #else /* !CONFIG_ACPI_SLEEP */
 565 static inline void save_pg_dir(void)
 566 {
 567 }
 568 #endif /* !CONFIG_ACPI_SLEEP */
 569
 570 void zap_low_mappings(void)
 571 {
 572         int i;
 573
 574         /*
 575          * Zap initial low-memory mappings.
 576          *
 577          * Note that "pgd_clear()" doesn't do it for
 578          * us, because pgd_clear() is a no-op on i386.
 579          */
 580         for (i = 0; i < KERNEL_PGD_BOUNDARY; i++) {
 581 #ifdef CONFIG_X86_PAE
 582                 set_pgd(swapper_pg_dir+i, __pgd(1 + __pa(empty_zero_page)));
 583 #else
 584                 set_pgd(swapper_pg_dir+i, __pgd(0));
 585 #endif
 586         }
 587         flush_tlb_all();
 588 }
 589
 590 int nx_enabled;
 591
 592 pteval_t __supported_pte_mask __read_mostly = ~(_PAGE_NX | _PAGE_GLOBAL | _PAGE_IOMAP);
 593 EXPORT_SYMBOL_GPL(__supported_pte_mask);
 594
 595 #ifdef CONFIG_X86_PAE
 596
 597 static int disable_nx __initdata;
 598
 599 /*
 600  * noexec = on|off
 601  *
 602  * Control non executable mappings.
 603  *
 604  * on      Enable
 605  * off     Disable
 606  */
 607 static int __init noexec_setup(char *str)
 608 {
 609         if (!str || !strcmp(str, "on")) {
 610                 if (cpu_has_nx) {
 611                         __supported_pte_mask |= _PAGE_NX;
 612                         disable_nx = 0;
 613                 }
 614         } else {
 615                 if (!strcmp(str, "off")) {
 616                         disable_nx = 1;
 617                         __supported_pte_mask &= ~_PAGE_NX;
 618                 } else {
 619                         return -EINVAL;
 620                 }
 621         }
 622
 623         return 0;
 624 }
 625 early_param("noexec", noexec_setup);
 626
 627 void __init set_nx(void)
 628 {
 629         unsigned int v[4], l, h;
 630
 631         if (cpu_has_pae && (cpuid_eax(0x80000000) > 0x80000001)) {
 632                 cpuid(0x80000001, &v[0], &v[1], &v[2], &v[3]);
 633
 634                 if ((v[3] & (1 << 20)) && !disable_nx) {
 635                         rdmsr(MSR_EFER, l, h);
 636                         l |= EFER_NX;
 637                         wrmsr(MSR_EFER, l, h);
 638                         nx_enabled = 1;
 639                         __supported_pte_mask |= _PAGE_NX;
 640                 }
 641         }
 642 }
 643 #endif
 644
 645 /* user-defined highmem size */
 646 static unsigned int highmem_pages = -1;
 647
 648 /*
 649  * highmem=size forces highmem to be exactly 'size' bytes.
 650  * This works even on boxes that have no highmem otherwise.
 651  * This also works to reduce highmem size on bigger boxes.
 652  */
 653 static int __init parse_highmem(char *arg)
 654 {
 655         if (!arg)
 656                 return -EINVAL;
 657
 658         highmem_pages = memparse(arg, &arg) >> PAGE_SHIFT;
 659         return 0;
 660 }
 661 early_param("highmem", parse_highmem);
 662
 663 #define MSG_HIGHMEM_TOO_BIG \
 664         "highmem size (%luMB) is bigger than pages available (%luMB)!\n"
 665
 666 #define MSG_LOWMEM_TOO_SMALL \
 667         "highmem size (%luMB) results in <64MB lowmem, ignoring it!\n"
 668 /*
 669  * All of RAM fits into lowmem - but if user wants highmem
 670  * artificially via the highmem=x boot parameter then create
 671  * it:
 672  */
 673 void __init lowmem_pfn_init(void)
 674 {
 675         /* max_low_pfn is 0, we already have early_res support */
 676         max_low_pfn = max_pfn;
 677
 678         if (highmem_pages == -1)
 679                 highmem_pages = 0;
 680 #ifdef CONFIG_HIGHMEM
 681         if (highmem_pages >= max_pfn) {
 682                 printk(KERN_ERR MSG_HIGHMEM_TOO_BIG,
 683                         pages_to_mb(highmem_pages), pages_to_mb(max_pfn));
 684                 highmem_pages = 0;
 685         }
 686         if (highmem_pages) {
 687                 if (max_low_pfn - highmem_pages < 64*1024*1024/PAGE_SIZE) {
 688                         printk(KERN_ERR MSG_LOWMEM_TOO_SMALL,
 689                                 pages_to_mb(highmem_pages));
 690                         highmem_pages = 0;
 691                 }
 692                 max_low_pfn -= highmem_pages;
 693         }
 694 #else
 695         if (highmem_pages)
 696                 printk(KERN_ERR "ignoring highmem size on non-highmem kernel!\n");
 697 #endif
 698 }
 699
 700 #define MSG_HIGHMEM_TOO_SMALL \
 701         "only %luMB highmem pages available, ignoring highmem size of %luMB!\n"
 702
 703 #define MSG_HIGHMEM_TRIMMED \
 704         "Warning: only 4GB will be used. Use a HIGHMEM64G enabled kernel!\n"
 705 /*
 706  * We have more RAM than fits into lowmem - we try to put it into
 707  * highmem, also taking the highmem=x boot parameter into account:
 708  */
 709 void __init highmem_pfn_init(void)
 710 {
 711         max_low_pfn = MAXMEM_PFN;
 712
 713         if (highmem_pages == -1)
 714                 highmem_pages = max_pfn - MAXMEM_PFN;
 715
 716         if (highmem_pages + MAXMEM_PFN < max_pfn)
 717                 max_pfn = MAXMEM_PFN + highmem_pages;
 718
 719         if (highmem_pages + MAXMEM_PFN > max_pfn) {
 720                 printk(KERN_WARNING MSG_HIGHMEM_TOO_SMALL,
 721                         pages_to_mb(max_pfn - MAXMEM_PFN),
 722                         pages_to_mb(highmem_pages));
 723                 highmem_pages = 0;
 724         }
 725 #ifndef CONFIG_HIGHMEM
 726         /* Maximum memory usable is what is directly addressable */
 727         printk(KERN_WARNING "Warning only %ldMB will be used.\n", MAXMEM>>20);
 728         if (max_pfn > MAX_NONPAE_PFN)
 729                 printk(KERN_WARNING "Use a HIGHMEM64G enabled kernel.\n");
 730         else
 731                 printk(KERN_WARNING "Use a HIGHMEM enabled kernel.\n");
 732         max_pfn = MAXMEM_PFN;
 733 #else /* !CONFIG_HIGHMEM */
 734 #ifndef CONFIG_HIGHMEM64G
 735         if (max_pfn > MAX_NONPAE_PFN) {
 736                 max_pfn = MAX_NONPAE_PFN;
 737                 printk(KERN_WARNING MSG_HIGHMEM_TRIMMED);
 738         }
 739 #endif /* !CONFIG_HIGHMEM64G */
 740 #endif /* !CONFIG_HIGHMEM */
 741 }
 742
 743 /*
 744  * Determine low and high memory ranges:
 745  */
 746 void __init find_low_pfn_range(void)
 747 {
 748         /* it could update max_pfn */
 749
 750         if (max_pfn <= MAXMEM_PFN)
 751                 lowmem_pfn_init();
 752         else
 753                 highmem_pfn_init();
 754 }
 755
 756 #ifndef CONFIG_NEED_MULTIPLE_NODES
 757 void __init initmem_init(unsigned long start_pfn,
 758                                   unsigned long end_pfn)
 759 {
 760 #ifdef CONFIG_HIGHMEM
 761         highstart_pfn = highend_pfn = max_pfn;
 762         if (max_pfn > max_low_pfn)
 763                 highstart_pfn = max_low_pfn;
 764         memory_present(0, 0, highend_pfn);
 765         e820_register_active_regions(0, 0, highend_pfn);
 766         printk(KERN_NOTICE "%ldMB HIGHMEM available.\n",
 767                 pages_to_mb(highend_pfn - highstart_pfn));
 768         num_physpages = highend_pfn;
 769         high_memory = (void *) __va(highstart_pfn * PAGE_SIZE - 1) + 1;
 770 #else
 771         memory_present(0, 0, max_low_pfn);
 772         e820_register_active_regions(0, 0, max_low_pfn);
 773         num_physpages = max_low_pfn;
 774         high_memory = (void *) __va(max_low_pfn * PAGE_SIZE - 1) + 1;
 775 #endif
 776 #ifdef CONFIG_FLATMEM
 777         max_mapnr = num_physpages;
 778 #endif
 779         __vmalloc_start_set = true;
 780
 781         printk(KERN_NOTICE "%ldMB LOWMEM available.\n",
 782                         pages_to_mb(max_low_pfn));
 783
 784         setup_bootmem_allocator();
 785 }
 786 #endif /* !CONFIG_NEED_MULTIPLE_NODES */
 787
 788 static void __init zone_sizes_init(void)
 789 {
 790         unsigned long max_zone_pfns[MAX_NR_ZONES];
 791         memset(max_zone_pfns, 0, sizeof(max_zone_pfns));
 792         max_zone_pfns[ZONE_DMA] =
 793                 virt_to_phys((char *)MAX_DMA_ADDRESS) >> PAGE_SHIFT;
 794         max_zone_pfns[ZONE_NORMAL] = max_low_pfn;
 795 #ifdef CONFIG_HIGHMEM
 796         max_zone_pfns[ZONE_HIGHMEM] = highend_pfn;
 797 #endif
 798
 799         free_area_init_nodes(max_zone_pfns);
 800 }
 801
 802 static unsigned long __init setup_node_bootmem(int nodeid,
 803                                  unsigned long start_pfn,
 804                                  unsigned long end_pfn,
 805                                  unsigned long bootmap)
 806 {
 807         unsigned long bootmap_size;
 808
 809         /* don't touch min_low_pfn */
 810         bootmap_size = init_bootmem_node(NODE_DATA(nodeid),
 811                                          bootmap >> PAGE_SHIFT,
 812                                          start_pfn, end_pfn);
 813         printk(KERN_INFO "  node %d low ram: %08lx - %08lx\n",
 814                 nodeid, start_pfn<<PAGE_SHIFT, end_pfn<<PAGE_SHIFT);
 815         printk(KERN_INFO "  node %d bootmap %08lx - %08lx\n",
 816                  nodeid, bootmap, bootmap + bootmap_size);
 817         free_bootmem_with_active_regions(nodeid, end_pfn);
 818         early_res_to_bootmem(start_pfn<<PAGE_SHIFT, end_pfn<<PAGE_SHIFT);
 819
 820         return bootmap + bootmap_size;
 821 }
 822
 823 void __init setup_bootmem_allocator(void)
 824 {
 825         int nodeid;
 826         unsigned long bootmap_size, bootmap;
 827         /*
 828          * Initialize the boot-time allocator (with low memory only):
 829          */
 830         bootmap_size = bootmem_bootmap_pages(max_low_pfn)<<PAGE_SHIFT;
 831         bootmap = find_e820_area(0, max_pfn_mapped<<PAGE_SHIFT, bootmap_size,
 832                                  PAGE_SIZE);
 833         if (bootmap == -1L)
 834                 panic("Cannot find bootmem map of size %ld\n", bootmap_size);
 835         reserve_early(bootmap, bootmap + bootmap_size, "BOOTMAP");
 836
 837         printk(KERN_INFO "  mapped low ram: 0 - %08lx\n",
 838                  max_pfn_mapped<<PAGE_SHIFT);
 839         printk(KERN_INFO "  low ram: 0 - %08lx\n", max_low_pfn<<PAGE_SHIFT);
 840
 841         for_each_online_node(nodeid) {
 842                  unsigned long start_pfn, end_pfn;
 843
 844 #ifdef CONFIG_NEED_MULTIPLE_NODES
 845                 start_pfn = node_start_pfn[nodeid];
 846                 end_pfn = node_end_pfn[nodeid];
 847                 if (start_pfn > max_low_pfn)
 848                         continue;
 849                 if (end_pfn > max_low_pfn)
 850                         end_pfn = max_low_pfn;
 851 #else
 852                 start_pfn = 0;
 853                 end_pfn = max_low_pfn;
 854 #endif
 855                 bootmap = setup_node_bootmem(nodeid, start_pfn, end_pfn,
 856                                                  bootmap);
 857         }
 858
 859         after_bootmem = 1;
 860 }
 861
 862 /*
 863  * paging_init() sets up the page tables - note that the first 8MB are
 864  * already mapped by head.S.
 865  *
 866  * This routines also unmaps the page at virtual kernel address 0, so
 867  * that we can trap those pesky NULL-reference errors in the kernel.
 868  */
 869 void __init paging_init(void)
 870 {
 871         pagetable_init();
 872
 873         __flush_tlb_all();
 874
 875         kmap_init();
 876
 877         /*
 878          * NOTE: at this point the bootmem allocator is fully available.
 879          */
 880         sparse_init();
 881         zone_sizes_init();
 882 }
 883
 884 /*
 885  * Test if the WP bit works in supervisor mode. It isn't supported on 386's
 886  * and also on some strange 486's. All 586+'s are OK. This used to involve
 887  * black magic jumps to work around some nasty CPU bugs, but fortunately the
 888  * switch to using exceptions got rid of all that.
 889  */
 890 static void __init test_wp_bit(void)
 891 {
 892         printk(KERN_INFO
 893   "Checking if this processor honours the WP bit even in supervisor mode...");
 894
 895         /* Any page-aligned address will do, the test is non-destructive */
 896         __set_fixmap(FIX_WP_TEST, __pa(&swapper_pg_dir), PAGE_READONLY);
 897         boot_cpu_data.wp_works_ok = do_test_wp_bit();
 898         clear_fixmap(FIX_WP_TEST);
 899
 900         if (!boot_cpu_data.wp_works_ok) {
 901                 printk(KERN_CONT "No.\n");
 902 #ifdef CONFIG_X86_WP_WORKS_OK
 903                 panic(
 904   "This kernel doesn't support CPU's with broken WP. Recompile it for a 386!");
 905 #endif
 906         } else {
 907                 printk(KERN_CONT "Ok.\n");
 908         }
 909 }
 910
 911 static struct kcore_list kcore_mem, kcore_vmalloc;
 912
 913 void __init mem_init(void)
 914 {
 915         int codesize, reservedpages, datasize, initsize;
 916         int tmp;
 917
 918         pci_iommu_alloc();
 919
 920 #ifdef CONFIG_FLATMEM
 921         BUG_ON(!mem_map);
 922 #endif
 923         /* this will put all low memory onto the freelists */
 924         totalram_pages += free_all_bootmem();
 925
 926         reservedpages = 0;
 927         for (tmp = 0; tmp < max_low_pfn; tmp++)
 928                 /*
 929                  * Only count reserved RAM pages:
 930                  */
 931                 if (page_is_ram(tmp) && PageReserved(pfn_to_page(tmp)))
 932                         reservedpages++;
 933
 934         set_highmem_pages_init();
 935
 936         codesize =  (unsigned long) &_etext - (unsigned long) &_text;
 937         datasize =  (unsigned long) &_edata - (unsigned long) &_etext;
 938         initsize =  (unsigned long) &__init_end - (unsigned long) &__init_begin;
 939
 940         kclist_add(&kcore_mem, __va(0), max_low_pfn << PAGE_SHIFT);
 941         kclist_add(&kcore_vmalloc, (void *)VMALLOC_START,
 942                    VMALLOC_END-VMALLOC_START);
 943
 944         printk(KERN_INFO "Memory: %luk/%luk available (%dk kernel code, "
 945                         "%dk reserved, %dk data, %dk init, %ldk highmem)\n",
 946                 (unsigned long) nr_free_pages() << (PAGE_SHIFT-10),
 947                 num_physpages << (PAGE_SHIFT-10),
 948                 codesize >> 10,
 949                 reservedpages << (PAGE_SHIFT-10),
 950                 datasize >> 10,
 951                 initsize >> 10,
 952                 (unsigned long) (totalhigh_pages << (PAGE_SHIFT-10))
 953                );
 954
 955         printk(KERN_INFO "virtual kernel memory layout:\n"
 956                 "    fixmap  : 0x%08lx - 0x%08lx   (%4ld kB)\n"
 957 #ifdef CONFIG_HIGHMEM
 958                 "    pkmap   : 0x%08lx - 0x%08lx   (%4ld kB)\n"
 959 #endif
 960                 "    vmalloc : 0x%08lx - 0x%08lx   (%4ld MB)\n"
 961                 "    lowmem  : 0x%08lx - 0x%08lx   (%4ld MB)\n"
 962                 "      .init : 0x%08lx - 0x%08lx   (%4ld kB)\n"
 963                 "      .data : 0x%08lx - 0x%08lx   (%4ld kB)\n"
 964                 "      .text : 0x%08lx - 0x%08lx   (%4ld kB)\n",
 965                 FIXADDR_START, FIXADDR_TOP,
 966                 (FIXADDR_TOP - FIXADDR_START) >> 10,
 967
 968 #ifdef CONFIG_HIGHMEM
 969                 PKMAP_BASE, PKMAP_BASE+LAST_PKMAP*PAGE_SIZE,
 970                 (LAST_PKMAP*PAGE_SIZE) >> 10,
 971 #endif
 972
 973                 VMALLOC_START, VMALLOC_END,
 974                 (VMALLOC_END - VMALLOC_START) >> 20,
 975
 976                 (unsigned long)__va(0), (unsigned long)high_memory,
 977                 ((unsigned long)high_memory - (unsigned long)__va(0)) >> 20,
 978
 979                 (unsigned long)&__init_begin, (unsigned long)&__init_end,
 980                 ((unsigned long)&__init_end -
 981                  (unsigned long)&__init_begin) >> 10,
 982
 983                 (unsigned long)&_etext, (unsigned long)&_edata,
 984                 ((unsigned long)&_edata - (unsigned long)&_etext) >> 10,
 985
 986                 (unsigned long)&_text, (unsigned long)&_etext,
 987                 ((unsigned long)&_etext - (unsigned long)&_text) >> 10);
 988
 989         /*
 990          * Check boundaries twice: Some fundamental inconsistencies can
 991          * be detected at build time already.
 992          */
 993 #define __FIXADDR_TOP (-PAGE_SIZE)
 994 #ifdef CONFIG_HIGHMEM
 995         BUILD_BUG_ON(PKMAP_BASE + LAST_PKMAP*PAGE_SIZE  > FIXADDR_START);
 996         BUILD_BUG_ON(VMALLOC_END                        > PKMAP_BASE);
 997 #endif
 998 #define high_memory (-128UL << 20)
 999         BUILD_BUG_ON(VMALLOC_START                      >= VMALLOC_END);
1000 #undef high_memory
1001 #undef __FIXADDR_TOP
1002
1003 #ifdef CONFIG_HIGHMEM
1004         BUG_ON(PKMAP_BASE + LAST_PKMAP*PAGE_SIZE        > FIXADDR_START);
1005         BUG_ON(VMALLOC_END                              > PKMAP_BASE);
1006 #endif
1007         BUG_ON(VMALLOC_START                            >= VMALLOC_END);
1008         BUG_ON((unsigned long)high_memory               > VMALLOC_START);
1009
1010         if (boot_cpu_data.wp_works_ok < 0)
1011                 test_wp_bit();
1012
1013         save_pg_dir();
1014         zap_low_mappings();
1015 }
1016
1017 #ifdef CONFIG_MEMORY_HOTPLUG
1018 int arch_add_memory(int nid, u64 start, u64 size)
1019 {
1020         struct pglist_data *pgdata = NODE_DATA(nid);
1021         struct zone *zone = pgdata->node_zones + ZONE_HIGHMEM;
1022         unsigned long start_pfn = start >> PAGE_SHIFT;
1023         unsigned long nr_pages = size >> PAGE_SHIFT;
1024
1025         return __add_pages(nid, zone, start_pfn, nr_pages);
1026 }
1027 #endif
1028
1029 /*
1030  * This function cannot be __init, since exceptions don't work in that
1031  * section.  Put this after the callers, so that it cannot be inlined.
1032  */
1033 static noinline int do_test_wp_bit(void)
1034 {
1035         char tmp_reg;
1036         int flag;
1037
1038         __asm__ __volatile__(
1039                 "       movb %0, %1     \n"
1040                 "1:     movb %1, %0     \n"
1041                 "       xorl %2, %2     \n"
1042                 "2:                     \n"
1043                 _ASM_EXTABLE(1b,2b)
1044                 :"=m" (*(char *)fix_to_virt(FIX_WP_TEST)),
1045                  "=q" (tmp_reg),
1046                  "=r" (flag)
1047                 :"2" (1)
1048                 :"memory");
1049
1050         return flag;
1051 }
1052
1053 #ifdef CONFIG_DEBUG_RODATA
1054 const int rodata_test_data = 0xC3;
1055 EXPORT_SYMBOL_GPL(rodata_test_data);
1056
1057 static int kernel_set_to_readonly;
1058
1059 void set_kernel_text_rw(void)
1060 {
1061         unsigned long start = PFN_ALIGN(_text);
1062         unsigned long size = PFN_ALIGN(_etext) - start;
1063
1064         if (!kernel_set_to_readonly)
1065                 return;
1066
1067         pr_debug("Set kernel text: %lx - %lx for read write\n",
1068                  start, start+size);
1069
1070         set_pages_rw(virt_to_page(start), size >> PAGE_SHIFT);
1071 }
1072
1073 void set_kernel_text_ro(void)
1074 {
1075         unsigned long start = PFN_ALIGN(_text);
1076         unsigned long size = PFN_ALIGN(_etext) - start;
1077
1078         if (!kernel_set_to_readonly)
1079                 return;
1080
1081         pr_debug("Set kernel text: %lx - %lx for read only\n",
1082                  start, start+size);
1083
1084         set_pages_ro(virt_to_page(start), size >> PAGE_SHIFT);
1085 }
1086
1087 void mark_rodata_ro(void)
1088 {
1089         unsigned long start = PFN_ALIGN(_text);
1090         unsigned long size = PFN_ALIGN(_etext) - start;
1091
1092         set_pages_ro(virt_to_page(start), size >> PAGE_SHIFT);
1093         printk(KERN_INFO "Write protecting the kernel text: %luk\n",
1094                 size >> 10);
1095
1096         kernel_set_to_readonly = 1;
1097
1098 #ifdef CONFIG_CPA_DEBUG
1099         printk(KERN_INFO "Testing CPA: Reverting %lx-%lx\n",
1100                 start, start+size);
1101         set_pages_rw(virt_to_page(start), size>>PAGE_SHIFT);
1102
1103         printk(KERN_INFO "Testing CPA: write protecting again\n");
1104         set_pages_ro(virt_to_page(start), size>>PAGE_SHIFT);
1105 #endif
1106
1107         start += size;
1108         size = (unsigned long)__end_rodata - start;
1109         set_pages_ro(virt_to_page(start), size >> PAGE_SHIFT);
1110         printk(KERN_INFO "Write protecting the kernel read-only data: %luk\n",
1111                 size >> 10);
1112         rodata_test();
1113
1114 #ifdef CONFIG_CPA_DEBUG
1115         printk(KERN_INFO "Testing CPA: undo %lx-%lx\n", start, start + size);
1116         set_pages_rw(virt_to_page(start), size >> PAGE_SHIFT);
1117
1118         printk(KERN_INFO "Testing CPA: write protecting again\n");
1119         set_pages_ro(virt_to_page(start), size >> PAGE_SHIFT);
1120 #endif
1121 }
1122 #endif
1123
1124 int __init reserve_bootmem_generic(unsigned long phys, unsigned long len,
1125                                    int flags)
1126 {
1127         return reserve_bootmem(phys, len, flags);
1128 }