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/memblock.h>
  29 #include <linux/proc_fs.h>
  30 #include <linux/memory_hotplug.h>
  31 #include <linux/initrd.h>
  32 #include <linux/cpumask.h>
  33 #include <linux/gfp.h>
  34
  35 #include <asm/asm.h>
  36 #include <asm/bios_ebda.h>
  37 #include <asm/processor.h>
  38 #include <asm/system.h>
  39 #include <asm/uaccess.h>
  40 #include <asm/pgtable.h>
  41 #include <asm/dma.h>
  42 #include <asm/fixmap.h>
  43 #include <asm/e820.h>
  44 #include <asm/apic.h>
  45 #include <asm/bugs.h>
  46 #include <asm/tlb.h>
  47 #include <asm/tlbflush.h>
  48 #include <asm/olpc_ofw.h>
  49 #include <asm/pgalloc.h>
  50 #include <asm/sections.h>
  51 #include <asm/paravirt.h>
  52 #include <asm/setup.h>
  53 #include <asm/cacheflush.h>
  54 #include <asm/page_types.h>
  55 #include <asm/init.h>
  56
  57 unsigned long highstart_pfn, highend_pfn;
  58
  59 static noinline int do_test_wp_bit(void);
  60
  61 bool __read_mostly __vmalloc_start_set = false;
  62
  63 static __init void *alloc_low_page(void)
  64 {
  65         unsigned long pfn = e820_table_end++;
  66         void *adr;
  67
  68         if (pfn >= e820_table_top)
  69                 panic("alloc_low_page: ran out of memory");
  70
  71         adr = __va(pfn * PAGE_SIZE);
  72         clear_page(adr);
  73         return adr;
  74 }
  75
  76 /*
  77  * Creates a middle page table and puts a pointer to it in the
  78  * given global directory entry. This only returns the gd entry
  79  * in non-PAE compilation mode, since the middle layer is folded.
  80  */
  81 static pmd_t * __init one_md_table_init(pgd_t *pgd)
  82 {
  83         pud_t *pud;
  84         pmd_t *pmd_table;
  85
  86 #ifdef CONFIG_X86_PAE
  87         if (!(pgd_val(*pgd) & _PAGE_PRESENT)) {
  88                 if (after_bootmem)
  89                         pmd_table = (pmd_t *)alloc_bootmem_pages(PAGE_SIZE);
  90                 else
  91                         pmd_table = (pmd_t *)alloc_low_page();
  92                 paravirt_alloc_pmd(&init_mm, __pa(pmd_table) >> PAGE_SHIFT);
  93                 set_pgd(pgd, __pgd(__pa(pmd_table) | _PAGE_PRESENT));
  94                 pud = pud_offset(pgd, 0);
  95                 BUG_ON(pmd_table != pmd_offset(pud, 0));
  96
  97                 return pmd_table;
  98         }
  99 #endif
 100         pud = pud_offset(pgd, 0);
 101         pmd_table = pmd_offset(pud, 0);
 102
 103         return pmd_table;
 104 }
 105
 106 /*
 107  * Create a page table and place a pointer to it in a middle page
 108  * directory entry:
 109  */
 110 static pte_t * __init one_page_table_init(pmd_t *pmd)
 111 {
 112         if (!(pmd_val(*pmd) & _PAGE_PRESENT)) {
 113                 pte_t *page_table = NULL;
 114
 115                 if (after_bootmem) {
 116 #if defined(CONFIG_DEBUG_PAGEALLOC) || defined(CONFIG_KMEMCHECK)
 117                         page_table = (pte_t *) alloc_bootmem_pages(PAGE_SIZE);
 118 #endif
 119                         if (!page_table)
 120                                 page_table =
 121                                 (pte_t *)alloc_bootmem_pages(PAGE_SIZE);
 122                 } else
 123                         page_table = (pte_t *)alloc_low_page();
 124
 125                 paravirt_alloc_pte(&init_mm, __pa(page_table) >> PAGE_SHIFT);
 126                 set_pmd(pmd, __pmd(__pa(page_table) | _PAGE_TABLE));
 127                 BUG_ON(page_table != pte_offset_kernel(pmd, 0));
 128         }
 129
 130         return pte_offset_kernel(pmd, 0);
 131 }
 132
 133 pmd_t * __init populate_extra_pmd(unsigned long vaddr)
 134 {
 135         int pgd_idx = pgd_index(vaddr);
 136         int pmd_idx = pmd_index(vaddr);
 137
 138         return one_md_table_init(swapper_pg_dir + pgd_idx) + pmd_idx;
 139 }
 140
 141 pte_t * __init populate_extra_pte(unsigned long vaddr)
 142 {
 143         int pte_idx = pte_index(vaddr);
 144         pmd_t *pmd;
 145
 146         pmd = populate_extra_pmd(vaddr);
 147         return one_page_table_init(pmd) + pte_idx;
 148 }
 149
 150 static pte_t *__init page_table_kmap_check(pte_t *pte, pmd_t *pmd,
 151                                            unsigned long vaddr, pte_t *lastpte)
 152 {
 153 #ifdef CONFIG_HIGHMEM
 154         /*
 155          * Something (early fixmap) may already have put a pte
 156          * page here, which causes the page table allocation
 157          * to become nonlinear. Attempt to fix it, and if it
 158          * is still nonlinear then we have to bug.
 159          */
 160         int pmd_idx_kmap_begin = fix_to_virt(FIX_KMAP_END) >> PMD_SHIFT;
 161         int pmd_idx_kmap_end = fix_to_virt(FIX_KMAP_BEGIN) >> PMD_SHIFT;
 162
 163         if (pmd_idx_kmap_begin != pmd_idx_kmap_end
 164             && (vaddr >> PMD_SHIFT) >= pmd_idx_kmap_begin
 165             && (vaddr >> PMD_SHIFT) <= pmd_idx_kmap_end
 166             && ((__pa(pte) >> PAGE_SHIFT) < e820_table_start
 167                 || (__pa(pte) >> PAGE_SHIFT) >= e820_table_end)) {
 168                 pte_t *newpte;
 169                 int i;
 170
 171                 BUG_ON(after_bootmem);
 172                 newpte = alloc_low_page();
 173                 for (i = 0; i < PTRS_PER_PTE; i++)
 174                         set_pte(newpte + i, pte[i]);
 175
 176                 paravirt_alloc_pte(&init_mm, __pa(newpte) >> PAGE_SHIFT);
 177                 set_pmd(pmd, __pmd(__pa(newpte)|_PAGE_TABLE));
 178                 BUG_ON(newpte != pte_offset_kernel(pmd, 0));
 179                 __flush_tlb_all();
 180
 181                 paravirt_release_pte(__pa(pte) >> PAGE_SHIFT);
 182                 pte = newpte;
 183         }
 184         BUG_ON(vaddr < fix_to_virt(FIX_KMAP_BEGIN - 1)
 185                && vaddr > fix_to_virt(FIX_KMAP_END)
 186                && lastpte && lastpte + PTRS_PER_PTE != pte);
 187 #endif
 188         return pte;
 189 }
 190
 191 /*
 192  * This function initializes a certain range of kernel virtual memory
 193  * with new bootmem page tables, everywhere page tables are missing in
 194  * the given range.
 195  *
 196  * NOTE: The pagetables are allocated contiguous on the physical space
 197  * so we can cache the place of the first one and move around without
 198  * checking the pgd every time.
 199  */
 200 static void __init
 201 page_table_range_init(unsigned long start, unsigned long end, pgd_t *pgd_base)
 202 {
 203         int pgd_idx, pmd_idx;
 204         unsigned long vaddr;
 205         pgd_t *pgd;
 206         pmd_t *pmd;
 207         pte_t *pte = NULL;
 208
 209         vaddr = start;
 210         pgd_idx = pgd_index(vaddr);
 211         pmd_idx = pmd_index(vaddr);
 212         pgd = pgd_base + pgd_idx;
 213
 214         for ( ; (pgd_idx < PTRS_PER_PGD) && (vaddr != end); pgd++, pgd_idx++) {
 215                 pmd = one_md_table_init(pgd);
 216                 pmd = pmd + pmd_index(vaddr);
 217                 for (; (pmd_idx < PTRS_PER_PMD) && (vaddr != end);
 218                                                         pmd++, pmd_idx++) {
 219                         pte = page_table_kmap_check(one_page_table_init(pmd),
 220                                                     pmd, vaddr, pte);
 221
 222                         vaddr += PMD_SIZE;
 223                 }
 224                 pmd_idx = 0;
 225         }
 226 }
 227
 228 static inline int is_kernel_text(unsigned long addr)
 229 {
 230         if (addr >= (unsigned long)_text && addr <= (unsigned long)__init_end)
 231                 return 1;
 232         return 0;
 233 }
 234
 235 /*
 236  * This maps the physical memory to kernel virtual address space, a total
 237  * of max_low_pfn pages, by creating page tables starting from address
 238  * PAGE_OFFSET:
 239  */
 240 unsigned long __init
 241 kernel_physical_mapping_init(unsigned long start,
 242                              unsigned long end,
 243                              unsigned long page_size_mask)
 244 {
 245         int use_pse = page_size_mask == (1<<PG_LEVEL_2M);
 246         unsigned long last_map_addr = end;
 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                                         last_map_addr = (pfn << PAGE_SHIFT) + PAGE_SIZE;
 350                                 } else
 351                                         set_pte(pte, pfn_pte(pfn, prot));
 352                         }
 353                 }
 354         }
 355         if (mapping_iter == 1) {
 356                 /*
 357                  * update direct mapping page count only in the first
 358                  * iteration.
 359                  */
 360                 update_page_count(PG_LEVEL_2M, pages_2m);
 361                 update_page_count(PG_LEVEL_4K, pages_4k);
 362
 363                 /*
 364                  * local global flush tlb, which will flush the previous
 365                  * mappings present in both small and large page TLB's.
 366                  */
 367                 __flush_tlb_all();
 368
 369                 /*
 370                  * Second iteration will set the actual desired PTE attributes.
 371                  */
 372                 mapping_iter = 2;
 373                 goto repeat;
 374         }
 375         return last_map_addr;
 376 }
 377
 378 pte_t *kmap_pte;
 379 pgprot_t kmap_prot;
 380
 381 static inline pte_t *kmap_get_fixmap_pte(unsigned long vaddr)
 382 {
 383         return pte_offset_kernel(pmd_offset(pud_offset(pgd_offset_k(vaddr),
 384                         vaddr), vaddr), vaddr);
 385 }
 386
 387 static void __init kmap_init(void)
 388 {
 389         unsigned long kmap_vstart;
 390
 391         /*
 392          * Cache the first kmap pte:
 393          */
 394         kmap_vstart = __fix_to_virt(FIX_KMAP_BEGIN);
 395         kmap_pte = kmap_get_fixmap_pte(kmap_vstart);
 396
 397         kmap_prot = PAGE_KERNEL;
 398 }
 399
 400 #ifdef CONFIG_HIGHMEM
 401 static void __init permanent_kmaps_init(pgd_t *pgd_base)
 402 {
 403         unsigned long vaddr;
 404         pgd_t *pgd;
 405         pud_t *pud;
 406         pmd_t *pmd;
 407         pte_t *pte;
 408
 409         vaddr = PKMAP_BASE;
 410         page_table_range_init(vaddr, vaddr + PAGE_SIZE*LAST_PKMAP, pgd_base);
 411
 412         pgd = swapper_pg_dir + pgd_index(vaddr);
 413         pud = pud_offset(pgd, vaddr);
 414         pmd = pmd_offset(pud, vaddr);
 415         pte = pte_offset_kernel(pmd, vaddr);
 416         pkmap_page_table = pte;
 417 }
 418
 419 static void __init add_one_highpage_init(struct page *page)
 420 {
 421         ClearPageReserved(page);
 422         init_page_count(page);
 423         __free_page(page);
 424         totalhigh_pages++;
 425 }
 426
 427 void __init add_highpages_with_active_regions(int nid,
 428                          unsigned long start_pfn, unsigned long end_pfn)
 429 {
 430         struct range *range;
 431         int nr_range;
 432         int i;
 433
 434         nr_range = __get_free_all_memory_range(&range, nid, start_pfn, end_pfn);
 435
 436         for (i = 0; i < nr_range; i++) {
 437                 struct page *page;
 438                 int node_pfn;
 439
 440                 for (node_pfn = range[i].start; node_pfn < range[i].end;
 441                      node_pfn++) {
 442                         if (!pfn_valid(node_pfn))
 443                                 continue;
 444                         page = pfn_to_page(node_pfn);
 445                         add_one_highpage_init(page);
 446                 }
 447         }
 448 }
 449 #else
 450 static inline void permanent_kmaps_init(pgd_t *pgd_base)
 451 {
 452 }
 453 #endif /* CONFIG_HIGHMEM */
 454
 455 void __init native_pagetable_setup_start(pgd_t *base)
 456 {
 457         unsigned long pfn, va;
 458         pgd_t *pgd;
 459         pud_t *pud;
 460         pmd_t *pmd;
 461         pte_t *pte;
 462
 463         /*
 464          * Remove any mappings which extend past the end of physical
 465          * memory from the boot time page table:
 466          */
 467         for (pfn = max_low_pfn + 1; pfn < 1<<(32-PAGE_SHIFT); pfn++) {
 468                 va = PAGE_OFFSET + (pfn<<PAGE_SHIFT);
 469                 pgd = base + pgd_index(va);
 470                 if (!pgd_present(*pgd))
 471                         break;
 472
 473                 pud = pud_offset(pgd, va);
 474                 pmd = pmd_offset(pud, va);
 475                 if (!pmd_present(*pmd))
 476                         break;
 477
 478                 pte = pte_offset_kernel(pmd, va);
 479                 if (!pte_present(*pte))
 480                         break;
 481
 482                 pte_clear(NULL, va, pte);
 483         }
 484         paravirt_alloc_pmd(&init_mm, __pa(base) >> PAGE_SHIFT);
 485 }
 486
 487 void __init native_pagetable_setup_done(pgd_t *base)
 488 {
 489 }
 490
 491 /*
 492  * Build a proper pagetable for the kernel mappings.  Up until this
 493  * point, we've been running on some set of pagetables constructed by
 494  * the boot process.
 495  *
 496  * If we're booting on native hardware, this will be a pagetable
 497  * constructed in arch/x86/kernel/head_32.S.  The root of the
 498  * pagetable will be swapper_pg_dir.
 499  *
 500  * If we're booting paravirtualized under a hypervisor, then there are
 501  * more options: we may already be running PAE, and the pagetable may
 502  * or may not be based in swapper_pg_dir.  In any case,
 503  * paravirt_pagetable_setup_start() will set up swapper_pg_dir
 504  * appropriately for the rest of the initialization to work.
 505  *
 506  * In general, pagetable_init() assumes that the pagetable may already
 507  * be partially populated, and so it avoids stomping on any existing
 508  * mappings.
 509  */
 510 void __init early_ioremap_page_table_range_init(void)
 511 {
 512         pgd_t *pgd_base = swapper_pg_dir;
 513         unsigned long vaddr, end;
 514
 515         /*
 516          * Fixed mappings, only the page table structure has to be
 517          * created - mappings will be set by set_fixmap():
 518          */
 519         vaddr = __fix_to_virt(__end_of_fixed_addresses - 1) & PMD_MASK;
 520         end = (FIXADDR_TOP + PMD_SIZE - 1) & PMD_MASK;
 521         page_table_range_init(vaddr, end, pgd_base);
 522         early_ioremap_reset();
 523 }
 524
 525 static void __init pagetable_init(void)
 526 {
 527         pgd_t *pgd_base = swapper_pg_dir;
 528
 529         permanent_kmaps_init(pgd_base);
 530 }
 531
 532 pteval_t __supported_pte_mask __read_mostly = ~(_PAGE_NX | _PAGE_GLOBAL | _PAGE_IOMAP);
 533 EXPORT_SYMBOL_GPL(__supported_pte_mask);
 534
 535 /* user-defined highmem size */
 536 static unsigned int highmem_pages = -1;
 537
 538 /*
 539  * highmem=size forces highmem to be exactly 'size' bytes.
 540  * This works even on boxes that have no highmem otherwise.
 541  * This also works to reduce highmem size on bigger boxes.
 542  */
 543 static int __init parse_highmem(char *arg)
 544 {
 545         if (!arg)
 546                 return -EINVAL;
 547
 548         highmem_pages = memparse(arg, &arg) >> PAGE_SHIFT;
 549         return 0;
 550 }
 551 early_param("highmem", parse_highmem);
 552
 553 #define MSG_HIGHMEM_TOO_BIG \
 554         "highmem size (%luMB) is bigger than pages available (%luMB)!\n"
 555
 556 #define MSG_LOWMEM_TOO_SMALL \
 557         "highmem size (%luMB) results in <64MB lowmem, ignoring it!\n"
 558 /*
 559  * All of RAM fits into lowmem - but if user wants highmem
 560  * artificially via the highmem=x boot parameter then create
 561  * it:
 562  */
 563 void __init lowmem_pfn_init(void)
 564 {
 565         /* max_low_pfn is 0, we already have early_res support */
 566         max_low_pfn = max_pfn;
 567
 568         if (highmem_pages == -1)
 569                 highmem_pages = 0;
 570 #ifdef CONFIG_HIGHMEM
 571         if (highmem_pages >= max_pfn) {
 572                 printk(KERN_ERR MSG_HIGHMEM_TOO_BIG,
 573                         pages_to_mb(highmem_pages), pages_to_mb(max_pfn));
 574                 highmem_pages = 0;
 575         }
 576         if (highmem_pages) {
 577                 if (max_low_pfn - highmem_pages < 64*1024*1024/PAGE_SIZE) {
 578                         printk(KERN_ERR MSG_LOWMEM_TOO_SMALL,
 579                                 pages_to_mb(highmem_pages));
 580                         highmem_pages = 0;
 581                 }
 582                 max_low_pfn -= highmem_pages;
 583         }
 584 #else
 585         if (highmem_pages)
 586                 printk(KERN_ERR "ignoring highmem size on non-highmem kernel!\n");
 587 #endif
 588 }
 589
 590 #define MSG_HIGHMEM_TOO_SMALL \
 591         "only %luMB highmem pages available, ignoring highmem size of %luMB!\n"
 592
 593 #define MSG_HIGHMEM_TRIMMED \
 594         "Warning: only 4GB will be used. Use a HIGHMEM64G enabled kernel!\n"
 595 /*
 596  * We have more RAM than fits into lowmem - we try to put it into
 597  * highmem, also taking the highmem=x boot parameter into account:
 598  */
 599 void __init highmem_pfn_init(void)
 600 {
 601         max_low_pfn = MAXMEM_PFN;
 602
 603         if (highmem_pages == -1)
 604                 highmem_pages = max_pfn - MAXMEM_PFN;
 605
 606         if (highmem_pages + MAXMEM_PFN < max_pfn)
 607                 max_pfn = MAXMEM_PFN + highmem_pages;
 608
 609         if (highmem_pages + MAXMEM_PFN > max_pfn) {
 610                 printk(KERN_WARNING MSG_HIGHMEM_TOO_SMALL,
 611                         pages_to_mb(max_pfn - MAXMEM_PFN),
 612                         pages_to_mb(highmem_pages));
 613                 highmem_pages = 0;
 614         }
 615 #ifndef CONFIG_HIGHMEM
 616         /* Maximum memory usable is what is directly addressable */
 617         printk(KERN_WARNING "Warning only %ldMB will be used.\n", MAXMEM>>20);
 618         if (max_pfn > MAX_NONPAE_PFN)
 619                 printk(KERN_WARNING "Use a HIGHMEM64G enabled kernel.\n");
 620         else
 621                 printk(KERN_WARNING "Use a HIGHMEM enabled kernel.\n");
 622         max_pfn = MAXMEM_PFN;
 623 #else /* !CONFIG_HIGHMEM */
 624 #ifndef CONFIG_HIGHMEM64G
 625         if (max_pfn > MAX_NONPAE_PFN) {
 626                 max_pfn = MAX_NONPAE_PFN;
 627                 printk(KERN_WARNING MSG_HIGHMEM_TRIMMED);
 628         }
 629 #endif /* !CONFIG_HIGHMEM64G */
 630 #endif /* !CONFIG_HIGHMEM */
 631 }
 632
 633 /*
 634  * Determine low and high memory ranges:
 635  */
 636 void __init find_low_pfn_range(void)
 637 {
 638         /* it could update max_pfn */
 639
 640         if (max_pfn <= MAXMEM_PFN)
 641                 lowmem_pfn_init();
 642         else
 643                 highmem_pfn_init();
 644 }
 645
 646 #ifndef CONFIG_NEED_MULTIPLE_NODES
 647 void __init initmem_init(void)
 648 {
 649 #ifdef CONFIG_HIGHMEM
 650         highstart_pfn = highend_pfn = max_pfn;
 651         if (max_pfn > max_low_pfn)
 652                 highstart_pfn = max_low_pfn;
 653         memblock_x86_register_active_regions(0, 0, highend_pfn);
 654         sparse_memory_present_with_active_regions(0);
 655         printk(KERN_NOTICE "%ldMB HIGHMEM available.\n",
 656                 pages_to_mb(highend_pfn - highstart_pfn));
 657         num_physpages = highend_pfn;
 658         high_memory = (void *) __va(highstart_pfn * PAGE_SIZE - 1) + 1;
 659 #else
 660         memblock_x86_register_active_regions(0, 0, max_low_pfn);
 661         sparse_memory_present_with_active_regions(0);
 662         num_physpages = max_low_pfn;
 663         high_memory = (void *) __va(max_low_pfn * PAGE_SIZE - 1) + 1;
 664 #endif
 665 #ifdef CONFIG_FLATMEM
 666         max_mapnr = num_physpages;
 667 #endif
 668         __vmalloc_start_set = true;
 669
 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         printk(KERN_INFO "  mapped low ram: 0 - %08lx\n",
 694                  max_pfn_mapped<<PAGE_SHIFT);
 695         printk(KERN_INFO "  low ram: 0 - %08lx\n", max_low_pfn<<PAGE_SHIFT);
 696
 697         after_bootmem = 1;
 698 }
 699
 700 /*
 701  * paging_init() sets up the page tables - note that the first 8MB are
 702  * already mapped by head.S.
 703  *
 704  * This routines also unmaps the page at virtual kernel address 0, so
 705  * that we can trap those pesky NULL-reference errors in the kernel.
 706  */
 707 void __init paging_init(void)
 708 {
 709         pagetable_init();
 710
 711         __flush_tlb_all();
 712
 713         kmap_init();
 714
 715         /*
 716          * NOTE: at this point the bootmem allocator is fully available.
 717          */
 718         olpc_dt_build_devicetree();
 719         sparse_init();
 720         zone_sizes_init();
 721 }
 722
 723 /*
 724  * Test if the WP bit works in supervisor mode. It isn't supported on 386's
 725  * and also on some strange 486's. All 586+'s are OK. This used to involve
 726  * black magic jumps to work around some nasty CPU bugs, but fortunately the
 727  * switch to using exceptions got rid of all that.
 728  */
 729 static void __init test_wp_bit(void)
 730 {
 731         printk(KERN_INFO
 732   "Checking if this processor honours the WP bit even in supervisor mode...");
 733
 734         /* Any page-aligned address will do, the test is non-destructive */
 735         __set_fixmap(FIX_WP_TEST, __pa(&swapper_pg_dir), PAGE_READONLY);
 736         boot_cpu_data.wp_works_ok = do_test_wp_bit();
 737         clear_fixmap(FIX_WP_TEST);
 738
 739         if (!boot_cpu_data.wp_works_ok) {
 740                 printk(KERN_CONT "No.\n");
 741 #ifdef CONFIG_X86_WP_WORKS_OK
 742                 panic(
 743   "This kernel doesn't support CPU's with broken WP. Recompile it for a 386!");
 744 #endif
 745         } else {
 746                 printk(KERN_CONT "Ok.\n");
 747         }
 748 }
 749
 750 void __init mem_init(void)
 751 {
 752         int codesize, reservedpages, datasize, initsize;
 753         int tmp;
 754
 755         pci_iommu_alloc();
 756
 757 #ifdef CONFIG_FLATMEM
 758         BUG_ON(!mem_map);
 759 #endif
 760         /* this will put all low memory onto the freelists */
 761         totalram_pages += free_all_bootmem();
 762
 763         reservedpages = 0;
 764         for (tmp = 0; tmp < max_low_pfn; tmp++)
 765                 /*
 766                  * Only count reserved RAM pages:
 767                  */
 768                 if (page_is_ram(tmp) && PageReserved(pfn_to_page(tmp)))
 769                         reservedpages++;
 770
 771         set_highmem_pages_init();
 772
 773         codesize =  (unsigned long) &_etext - (unsigned long) &_text;
 774         datasize =  (unsigned long) &_edata - (unsigned long) &_etext;
 775         initsize =  (unsigned long) &__init_end - (unsigned long) &__init_begin;
 776
 777         printk(KERN_INFO "Memory: %luk/%luk available (%dk kernel code, "
 778                         "%dk reserved, %dk data, %dk init, %ldk highmem)\n",
 779                 nr_free_pages() << (PAGE_SHIFT-10),
 780                 num_physpages << (PAGE_SHIFT-10),
 781                 codesize >> 10,
 782                 reservedpages << (PAGE_SHIFT-10),
 783                 datasize >> 10,
 784                 initsize >> 10,
 785                 totalhigh_pages << (PAGE_SHIFT-10));
 786
 787         printk(KERN_INFO "virtual kernel memory layout:\n"
 788                 "    fixmap  : 0x%08lx - 0x%08lx   (%4ld kB)\n"
 789 #ifdef CONFIG_HIGHMEM
 790                 "    pkmap   : 0x%08lx - 0x%08lx   (%4ld kB)\n"
 791 #endif
 792                 "    vmalloc : 0x%08lx - 0x%08lx   (%4ld MB)\n"
 793                 "    lowmem  : 0x%08lx - 0x%08lx   (%4ld MB)\n"
 794                 "      .init : 0x%08lx - 0x%08lx   (%4ld kB)\n"
 795                 "      .data : 0x%08lx - 0x%08lx   (%4ld kB)\n"
 796                 "      .text : 0x%08lx - 0x%08lx   (%4ld kB)\n",
 797                 FIXADDR_START, FIXADDR_TOP,
 798                 (FIXADDR_TOP - FIXADDR_START) >> 10,
 799
 800 #ifdef CONFIG_HIGHMEM
 801                 PKMAP_BASE, PKMAP_BASE+LAST_PKMAP*PAGE_SIZE,
 802                 (LAST_PKMAP*PAGE_SIZE) >> 10,
 803 #endif
 804
 805                 VMALLOC_START, VMALLOC_END,
 806                 (VMALLOC_END - VMALLOC_START) >> 20,
 807
 808                 (unsigned long)__va(0), (unsigned long)high_memory,
 809                 ((unsigned long)high_memory - (unsigned long)__va(0)) >> 20,
 810
 811                 (unsigned long)&__init_begin, (unsigned long)&__init_end,
 812                 ((unsigned long)&__init_end -
 813                  (unsigned long)&__init_begin) >> 10,
 814
 815                 (unsigned long)&_etext, (unsigned long)&_edata,
 816                 ((unsigned long)&_edata - (unsigned long)&_etext) >> 10,
 817
 818                 (unsigned long)&_text, (unsigned long)&_etext,
 819                 ((unsigned long)&_etext - (unsigned long)&_text) >> 10);
 820
 821         /*
 822          * Check boundaries twice: Some fundamental inconsistencies can
 823          * be detected at build time already.
 824          */
 825 #define __FIXADDR_TOP (-PAGE_SIZE)
 826 #ifdef CONFIG_HIGHMEM
 827         BUILD_BUG_ON(PKMAP_BASE + LAST_PKMAP*PAGE_SIZE  > FIXADDR_START);
 828         BUILD_BUG_ON(VMALLOC_END                        > PKMAP_BASE);
 829 #endif
 830 #define high_memory (-128UL << 20)
 831         BUILD_BUG_ON(VMALLOC_START                      >= VMALLOC_END);
 832 #undef high_memory
 833 #undef __FIXADDR_TOP
 834
 835 #ifdef CONFIG_HIGHMEM
 836         BUG_ON(PKMAP_BASE + LAST_PKMAP*PAGE_SIZE        > FIXADDR_START);
 837         BUG_ON(VMALLOC_END                              > PKMAP_BASE);
 838 #endif
 839         BUG_ON(VMALLOC_START                            >= VMALLOC_END);
 840         BUG_ON((unsigned long)high_memory               > VMALLOC_START);
 841
 842         if (boot_cpu_data.wp_works_ok < 0)
 843                 test_wp_bit();
 844 }
 845
 846 #ifdef CONFIG_MEMORY_HOTPLUG
 847 int arch_add_memory(int nid, u64 start, u64 size)
 848 {
 849         struct pglist_data *pgdata = NODE_DATA(nid);
 850         struct zone *zone = pgdata->node_zones + ZONE_HIGHMEM;
 851         unsigned long start_pfn = start >> PAGE_SHIFT;
 852         unsigned long nr_pages = size >> PAGE_SHIFT;
 853
 854         return __add_pages(nid, zone, start_pfn, nr_pages);
 855 }
 856 #endif
 857
 858 /*
 859  * This function cannot be __init, since exceptions don't work in that
 860  * section.  Put this after the callers, so that it cannot be inlined.
 861  */
 862 static noinline int do_test_wp_bit(void)
 863 {
 864         char tmp_reg;
 865         int flag;
 866
 867         __asm__ __volatile__(
 868                 "       movb %0, %1     \n"
 869                 "1:     movb %1, %0     \n"
 870                 "       xorl %2, %2     \n"
 871                 "2:                     \n"
 872                 _ASM_EXTABLE(1b,2b)
 873                 :"=m" (*(char *)fix_to_virt(FIX_WP_TEST)),
 874                  "=q" (tmp_reg),
 875                  "=r" (flag)
 876                 :"2" (1)
 877                 :"memory");
 878
 879         return flag;
 880 }
 881
 882 #ifdef CONFIG_DEBUG_RODATA
 883 const int rodata_test_data = 0xC3;
 884 EXPORT_SYMBOL_GPL(rodata_test_data);
 885
 886 int kernel_set_to_readonly __read_mostly;
 887
 888 void set_kernel_text_rw(void)
 889 {
 890         unsigned long start = PFN_ALIGN(_text);
 891         unsigned long size = PFN_ALIGN(_etext) - start;
 892
 893         if (!kernel_set_to_readonly)
 894                 return;
 895
 896         pr_debug("Set kernel text: %lx - %lx for read write\n",
 897                  start, start+size);
 898
 899         set_pages_rw(virt_to_page(start), size >> PAGE_SHIFT);
 900 }
 901
 902 void set_kernel_text_ro(void)
 903 {
 904         unsigned long start = PFN_ALIGN(_text);
 905         unsigned long size = PFN_ALIGN(_etext) - start;
 906
 907         if (!kernel_set_to_readonly)
 908                 return;
 909
 910         pr_debug("Set kernel text: %lx - %lx for read only\n",
 911                  start, start+size);
 912
 913         set_pages_ro(virt_to_page(start), size >> PAGE_SHIFT);
 914 }
 915
 916 static void mark_nxdata_nx(void)
 917 {
 918         /*
 919          * When this called, init has already been executed and released,
 920          * so everything past _etext sould be NX.
 921          */
 922         unsigned long start = PFN_ALIGN(_etext);
 923         /*
 924          * This comes from is_kernel_text upper limit. Also HPAGE where used:
 925          */
 926         unsigned long size = (((unsigned long)__init_end + HPAGE_SIZE) & HPAGE_MASK) - start;
 927
 928         if (__supported_pte_mask & _PAGE_NX)
 929                 printk(KERN_INFO "NX-protecting the kernel data: %luk\n", size >> 10);
 930         set_pages_nx(virt_to_page(start), size >> PAGE_SHIFT);
 931 }
 932
 933 void mark_rodata_ro(void)
 934 {
 935         unsigned long start = PFN_ALIGN(_text);
 936         unsigned long size = PFN_ALIGN(_etext) - start;
 937
 938         set_pages_ro(virt_to_page(start), size >> PAGE_SHIFT);
 939         printk(KERN_INFO "Write protecting the kernel text: %luk\n",
 940                 size >> 10);
 941
 942         kernel_set_to_readonly = 1;
 943
 944 #ifdef CONFIG_CPA_DEBUG
 945         printk(KERN_INFO "Testing CPA: Reverting %lx-%lx\n",
 946                 start, start+size);
 947         set_pages_rw(virt_to_page(start), size>>PAGE_SHIFT);
 948
 949         printk(KERN_INFO "Testing CPA: write protecting again\n");
 950         set_pages_ro(virt_to_page(start), size>>PAGE_SHIFT);
 951 #endif
 952
 953         start += size;
 954         size = (unsigned long)__end_rodata - start;
 955         set_pages_ro(virt_to_page(start), size >> PAGE_SHIFT);
 956         printk(KERN_INFO "Write protecting the kernel read-only data: %luk\n",
 957                 size >> 10);
 958         rodata_test();
 959
 960 #ifdef CONFIG_CPA_DEBUG
 961         printk(KERN_INFO "Testing CPA: undo %lx-%lx\n", start, start + size);
 962         set_pages_rw(virt_to_page(start), size >> PAGE_SHIFT);
 963
 964         printk(KERN_INFO "Testing CPA: write protecting again\n");
 965         set_pages_ro(virt_to_page(start), size >> PAGE_SHIFT);
 966 #endif
 967         mark_nxdata_nx();
 968 }
 969 #endif
 970