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/page_types.h>
  53 #include <asm/init.h>
  54
  55 unsigned long highstart_pfn, highend_pfn;
  56
  57 static noinline int do_test_wp_bit(void);
  58
  59 bool __read_mostly __vmalloc_start_set = false;
  60
  61 static __init void *alloc_low_page(void)
  62 {
  63         unsigned long pfn = e820_table_end++;
  64         void *adr;
  65
  66         if (pfn >= e820_table_top)
  67                 panic("alloc_low_page: ran out of memory");
  68
  69         adr = __va(pfn * PAGE_SIZE);
  70         memset(adr, 0, PAGE_SIZE);
  71         return adr;
  72 }
  73
  74 /*
  75  * Creates a middle page table and puts a pointer to it in the
  76  * given global directory entry. This only returns the gd entry
  77  * in non-PAE compilation mode, since the middle layer is folded.
  78  */
  79 static pmd_t * __init one_md_table_init(pgd_t *pgd)
  80 {
  81         pud_t *pud;
  82         pmd_t *pmd_table;
  83
  84 #ifdef CONFIG_X86_PAE
  85         if (!(pgd_val(*pgd) & _PAGE_PRESENT)) {
  86                 if (after_bootmem)
  87                         pmd_table = (pmd_t *)alloc_bootmem_pages(PAGE_SIZE);
  88                 else
  89                         pmd_table = (pmd_t *)alloc_low_page();
  90                 paravirt_alloc_pmd(&init_mm, __pa(pmd_table) >> PAGE_SHIFT);
  91                 set_pgd(pgd, __pgd(__pa(pmd_table) | _PAGE_PRESENT));
  92                 pud = pud_offset(pgd, 0);
  93                 BUG_ON(pmd_table != pmd_offset(pud, 0));
  94
  95                 return pmd_table;
  96         }
  97 #endif
  98         pud = pud_offset(pgd, 0);
  99         pmd_table = pmd_offset(pud, 0);
 100
 101         return pmd_table;
 102 }
 103
 104 /*
 105  * Create a page table and place a pointer to it in a middle page
 106  * directory entry:
 107  */
 108 static pte_t * __init one_page_table_init(pmd_t *pmd)
 109 {
 110         if (!(pmd_val(*pmd) & _PAGE_PRESENT)) {
 111                 pte_t *page_table = NULL;
 112
 113                 if (after_bootmem) {
 114 #if defined(CONFIG_DEBUG_PAGEALLOC) || defined(CONFIG_KMEMCHECK)
 115                         page_table = (pte_t *) alloc_bootmem_pages(PAGE_SIZE);
 116 #endif
 117                         if (!page_table)
 118                                 page_table =
 119                                 (pte_t *)alloc_bootmem_pages(PAGE_SIZE);
 120                 } else
 121                         page_table = (pte_t *)alloc_low_page();
 122
 123                 paravirt_alloc_pte(&init_mm, __pa(page_table) >> PAGE_SHIFT);
 124                 set_pmd(pmd, __pmd(__pa(page_table) | _PAGE_TABLE));
 125                 BUG_ON(page_table != pte_offset_kernel(pmd, 0));
 126         }
 127
 128         return pte_offset_kernel(pmd, 0);
 129 }
 130
 131 pmd_t * __init populate_extra_pmd(unsigned long vaddr)
 132 {
 133         int pgd_idx = pgd_index(vaddr);
 134         int pmd_idx = pmd_index(vaddr);
 135
 136         return one_md_table_init(swapper_pg_dir + pgd_idx) + pmd_idx;
 137 }
 138
 139 pte_t * __init populate_extra_pte(unsigned long vaddr)
 140 {
 141         int pte_idx = pte_index(vaddr);
 142         pmd_t *pmd;
 143
 144         pmd = populate_extra_pmd(vaddr);
 145         return one_page_table_init(pmd) + pte_idx;
 146 }
 147
 148 static pte_t *__init page_table_kmap_check(pte_t *pte, pmd_t *pmd,
 149                                            unsigned long vaddr, pte_t *lastpte)
 150 {
 151 #ifdef CONFIG_HIGHMEM
 152         /*
 153          * Something (early fixmap) may already have put a pte
 154          * page here, which causes the page table allocation
 155          * to become nonlinear. Attempt to fix it, and if it
 156          * is still nonlinear then we have to bug.
 157          */
 158         int pmd_idx_kmap_begin = fix_to_virt(FIX_KMAP_END) >> PMD_SHIFT;
 159         int pmd_idx_kmap_end = fix_to_virt(FIX_KMAP_BEGIN) >> PMD_SHIFT;
 160
 161         if (pmd_idx_kmap_begin != pmd_idx_kmap_end
 162             && (vaddr >> PMD_SHIFT) >= pmd_idx_kmap_begin
 163             && (vaddr >> PMD_SHIFT) <= pmd_idx_kmap_end
 164             && ((__pa(pte) >> PAGE_SHIFT) < e820_table_start
 165                 || (__pa(pte) >> PAGE_SHIFT) >= e820_table_end)) {
 166                 pte_t *newpte;
 167                 int i;
 168
 169                 BUG_ON(after_bootmem);
 170                 newpte = alloc_low_page();
 171                 for (i = 0; i < PTRS_PER_PTE; i++)
 172                         set_pte(newpte + i, pte[i]);
 173
 174                 paravirt_alloc_pte(&init_mm, __pa(newpte) >> PAGE_SHIFT);
 175                 set_pmd(pmd, __pmd(__pa(newpte)|_PAGE_TABLE));
 176                 BUG_ON(newpte != pte_offset_kernel(pmd, 0));
 177                 __flush_tlb_all();
 178
 179                 paravirt_release_pte(__pa(pte) >> PAGE_SHIFT);
 180                 pte = newpte;
 181         }
 182         BUG_ON(vaddr < fix_to_virt(FIX_KMAP_BEGIN - 1)
 183                && vaddr > fix_to_virt(FIX_KMAP_END)
 184                && lastpte && lastpte + PTRS_PER_PTE != pte);
 185 #endif
 186         return pte;
 187 }
 188
 189 /*
 190  * This function initializes a certain range of kernel virtual memory
 191  * with new bootmem page tables, everywhere page tables are missing in
 192  * the given range.
 193  *
 194  * NOTE: The pagetables are allocated contiguous on the physical space
 195  * so we can cache the place of the first one and move around without
 196  * checking the pgd every time.
 197  */
 198 static void __init
 199 page_table_range_init(unsigned long start, unsigned long end, pgd_t *pgd_base)
 200 {
 201         int pgd_idx, pmd_idx;
 202         unsigned long vaddr;
 203         pgd_t *pgd;
 204         pmd_t *pmd;
 205         pte_t *pte = NULL;
 206
 207         vaddr = start;
 208         pgd_idx = pgd_index(vaddr);
 209         pmd_idx = pmd_index(vaddr);
 210         pgd = pgd_base + pgd_idx;
 211
 212         for ( ; (pgd_idx < PTRS_PER_PGD) && (vaddr != end); pgd++, pgd_idx++) {
 213                 pmd = one_md_table_init(pgd);
 214                 pmd = pmd + pmd_index(vaddr);
 215                 for (; (pmd_idx < PTRS_PER_PMD) && (vaddr != end);
 216                                                         pmd++, pmd_idx++) {
 217                         pte = page_table_kmap_check(one_page_table_init(pmd),
 218                                                     pmd, vaddr, pte);
 219
 220                         vaddr += PMD_SIZE;
 221                 }
 222                 pmd_idx = 0;
 223         }
 224 }
 225
 226 static inline int is_kernel_text(unsigned long addr)
 227 {
 228         if (addr >= PAGE_OFFSET && addr <= (unsigned long)__init_end)
 229                 return 1;
 230         return 0;
 231 }
 232
 233 /*
 234  * This maps the physical memory to kernel virtual address space, a total
 235  * of max_low_pfn pages, by creating page tables starting from address
 236  * PAGE_OFFSET:
 237  */
 238 unsigned long __init
 239 kernel_physical_mapping_init(unsigned long start,
 240                              unsigned long end,
 241                              unsigned long page_size_mask)
 242 {
 243         int use_pse = page_size_mask == (1<<PG_LEVEL_2M);
 244         unsigned long last_map_addr = end;
 245         unsigned long start_pfn, end_pfn;
 246         pgd_t *pgd_base = swapper_pg_dir;
 247         int pgd_idx, pmd_idx, pte_ofs;
 248         unsigned long pfn;
 249         pgd_t *pgd;
 250         pmd_t *pmd;
 251         pte_t *pte;
 252         unsigned pages_2m, pages_4k;
 253         int mapping_iter;
 254
 255         start_pfn = start >> PAGE_SHIFT;
 256         end_pfn = end >> PAGE_SHIFT;
 257
 258         /*
 259          * First iteration will setup identity mapping using large/small pages
 260          * based on use_pse, with other attributes same as set by
 261          * the early code in head_32.S
 262          *
 263          * Second iteration will setup the appropriate attributes (NX, GLOBAL..)
 264          * as desired for the kernel identity mapping.
 265          *
 266          * This two pass mechanism conforms to the TLB app note which says:
 267          *
 268          *     "Software should not write to a paging-structure entry in a way
 269          *      that would change, for any linear address, both the page size
 270          *      and either the page frame or attributes."
 271          */
 272         mapping_iter = 1;
 273
 274         if (!cpu_has_pse)
 275                 use_pse = 0;
 276
 277 repeat:
 278         pages_2m = pages_4k = 0;
 279         pfn = start_pfn;
 280         pgd_idx = pgd_index((pfn<<PAGE_SHIFT) + PAGE_OFFSET);
 281         pgd = pgd_base + pgd_idx;
 282         for (; pgd_idx < PTRS_PER_PGD; pgd++, pgd_idx++) {
 283                 pmd = one_md_table_init(pgd);
 284
 285                 if (pfn >= end_pfn)
 286                         continue;
 287 #ifdef CONFIG_X86_PAE
 288                 pmd_idx = pmd_index((pfn<<PAGE_SHIFT) + PAGE_OFFSET);
 289                 pmd += pmd_idx;
 290 #else
 291                 pmd_idx = 0;
 292 #endif
 293                 for (; pmd_idx < PTRS_PER_PMD && pfn < end_pfn;
 294                      pmd++, pmd_idx++) {
 295                         unsigned int addr = pfn * PAGE_SIZE + PAGE_OFFSET;
 296
 297                         /*
 298                          * Map with big pages if possible, otherwise
 299                          * create normal page tables:
 300                          */
 301                         if (use_pse) {
 302                                 unsigned int addr2;
 303                                 pgprot_t prot = PAGE_KERNEL_LARGE;
 304                                 /*
 305                                  * first pass will use the same initial
 306                                  * identity mapping attribute + _PAGE_PSE.
 307                                  */
 308                                 pgprot_t init_prot =
 309                                         __pgprot(PTE_IDENT_ATTR |
 310                                                  _PAGE_PSE);
 311
 312                                 addr2 = (pfn + PTRS_PER_PTE-1) * PAGE_SIZE +
 313                                         PAGE_OFFSET + PAGE_SIZE-1;
 314
 315                                 if (is_kernel_text(addr) ||
 316                                     is_kernel_text(addr2))
 317                                         prot = PAGE_KERNEL_LARGE_EXEC;
 318
 319                                 pages_2m++;
 320                                 if (mapping_iter == 1)
 321                                         set_pmd(pmd, pfn_pmd(pfn, init_prot));
 322                                 else
 323                                         set_pmd(pmd, pfn_pmd(pfn, prot));
 324
 325                                 pfn += PTRS_PER_PTE;
 326                                 continue;
 327                         }
 328                         pte = one_page_table_init(pmd);
 329
 330                         pte_ofs = pte_index((pfn<<PAGE_SHIFT) + PAGE_OFFSET);
 331                         pte += pte_ofs;
 332                         for (; pte_ofs < PTRS_PER_PTE && pfn < end_pfn;
 333                              pte++, pfn++, pte_ofs++, addr += PAGE_SIZE) {
 334                                 pgprot_t prot = PAGE_KERNEL;
 335                                 /*
 336                                  * first pass will use the same initial
 337                                  * identity mapping attribute.
 338                                  */
 339                                 pgprot_t init_prot = __pgprot(PTE_IDENT_ATTR);
 340
 341                                 if (is_kernel_text(addr))
 342                                         prot = PAGE_KERNEL_EXEC;
 343
 344                                 pages_4k++;
 345                                 if (mapping_iter == 1) {
 346                                         set_pte(pte, pfn_pte(pfn, init_prot));
 347                                         last_map_addr = (pfn << PAGE_SHIFT) + PAGE_SIZE;
 348                                 } else
 349                                         set_pte(pte, pfn_pte(pfn, prot));
 350                         }
 351                 }
 352         }
 353         if (mapping_iter == 1) {
 354                 /*
 355                  * update direct mapping page count only in the first
 356                  * iteration.
 357                  */
 358                 update_page_count(PG_LEVEL_2M, pages_2m);
 359                 update_page_count(PG_LEVEL_4K, pages_4k);
 360
 361                 /*
 362                  * local global flush tlb, which will flush the previous
 363                  * mappings present in both small and large page TLB's.
 364                  */
 365                 __flush_tlb_all();
 366
 367                 /*
 368                  * Second iteration will set the actual desired PTE attributes.
 369                  */
 370                 mapping_iter = 2;
 371                 goto repeat;
 372         }
 373         return last_map_addr;
 374 }
 375
 376 pte_t *kmap_pte;
 377 pgprot_t kmap_prot;
 378
 379 static inline pte_t *kmap_get_fixmap_pte(unsigned long vaddr)
 380 {
 381         return pte_offset_kernel(pmd_offset(pud_offset(pgd_offset_k(vaddr),
 382                         vaddr), vaddr), vaddr);
 383 }
 384
 385 static void __init kmap_init(void)
 386 {
 387         unsigned long kmap_vstart;
 388
 389         /*
 390          * Cache the first kmap pte:
 391          */
 392         kmap_vstart = __fix_to_virt(FIX_KMAP_BEGIN);
 393         kmap_pte = kmap_get_fixmap_pte(kmap_vstart);
 394
 395         kmap_prot = PAGE_KERNEL;
 396 }
 397
 398 #ifdef CONFIG_HIGHMEM
 399 static void __init permanent_kmaps_init(pgd_t *pgd_base)
 400 {
 401         unsigned long vaddr;
 402         pgd_t *pgd;
 403         pud_t *pud;
 404         pmd_t *pmd;
 405         pte_t *pte;
 406
 407         vaddr = PKMAP_BASE;
 408         page_table_range_init(vaddr, vaddr + PAGE_SIZE*LAST_PKMAP, pgd_base);
 409
 410         pgd = swapper_pg_dir + pgd_index(vaddr);
 411         pud = pud_offset(pgd, vaddr);
 412         pmd = pmd_offset(pud, vaddr);
 413         pte = pte_offset_kernel(pmd, vaddr);
 414         pkmap_page_table = pte;
 415 }
 416
 417 static void __init add_one_highpage_init(struct page *page)
 418 {
 419         ClearPageReserved(page);
 420         init_page_count(page);
 421         __free_page(page);
 422         totalhigh_pages++;
 423 }
 424
 425 struct add_highpages_data {
 426         unsigned long start_pfn;
 427         unsigned long end_pfn;
 428 };
 429
 430 static int __init add_highpages_work_fn(unsigned long start_pfn,
 431                                          unsigned long end_pfn, void *datax)
 432 {
 433         int node_pfn;
 434         struct page *page;
 435         unsigned long final_start_pfn, final_end_pfn;
 436         struct add_highpages_data *data;
 437
 438         data = (struct add_highpages_data *)datax;
 439
 440         final_start_pfn = max(start_pfn, data->start_pfn);
 441         final_end_pfn = min(end_pfn, data->end_pfn);
 442         if (final_start_pfn >= final_end_pfn)
 443                 return 0;
 444
 445         for (node_pfn = final_start_pfn; node_pfn < final_end_pfn;
 446              node_pfn++) {
 447                 if (!pfn_valid(node_pfn))
 448                         continue;
 449                 page = pfn_to_page(node_pfn);
 450                 add_one_highpage_init(page);
 451         }
 452
 453         return 0;
 454
 455 }
 456
 457 void __init add_highpages_with_active_regions(int nid, unsigned long start_pfn,
 458                                               unsigned long end_pfn)
 459 {
 460         struct add_highpages_data data;
 461
 462         data.start_pfn = start_pfn;
 463         data.end_pfn = end_pfn;
 464
 465         work_with_active_regions(nid, add_highpages_work_fn, &data);
 466 }
 467
 468 #else
 469 static inline void permanent_kmaps_init(pgd_t *pgd_base)
 470 {
 471 }
 472 #endif /* CONFIG_HIGHMEM */
 473
 474 void __init native_pagetable_setup_start(pgd_t *base)
 475 {
 476         unsigned long pfn, va;
 477         pgd_t *pgd;
 478         pud_t *pud;
 479         pmd_t *pmd;
 480         pte_t *pte;
 481
 482         /*
 483          * Remove any mappings which extend past the end of physical
 484          * memory from the boot time page table:
 485          */
 486         for (pfn = max_low_pfn + 1; pfn < 1<<(32-PAGE_SHIFT); pfn++) {
 487                 va = PAGE_OFFSET + (pfn<<PAGE_SHIFT);
 488                 pgd = base + pgd_index(va);
 489                 if (!pgd_present(*pgd))
 490                         break;
 491
 492                 pud = pud_offset(pgd, va);
 493                 pmd = pmd_offset(pud, va);
 494                 if (!pmd_present(*pmd))
 495                         break;
 496
 497                 pte = pte_offset_kernel(pmd, va);
 498                 if (!pte_present(*pte))
 499                         break;
 500
 501                 pte_clear(NULL, va, pte);
 502         }
 503         paravirt_alloc_pmd(&init_mm, __pa(base) >> PAGE_SHIFT);
 504 }
 505
 506 void __init native_pagetable_setup_done(pgd_t *base)
 507 {
 508 }
 509
 510 /*
 511  * Build a proper pagetable for the kernel mappings.  Up until this
 512  * point, we've been running on some set of pagetables constructed by
 513  * the boot process.
 514  *
 515  * If we're booting on native hardware, this will be a pagetable
 516  * constructed in arch/x86/kernel/head_32.S.  The root of the
 517  * pagetable will be swapper_pg_dir.
 518  *
 519  * If we're booting paravirtualized under a hypervisor, then there are
 520  * more options: we may already be running PAE, and the pagetable may
 521  * or may not be based in swapper_pg_dir.  In any case,
 522  * paravirt_pagetable_setup_start() will set up swapper_pg_dir
 523  * appropriately for the rest of the initialization to work.
 524  *
 525  * In general, pagetable_init() assumes that the pagetable may already
 526  * be partially populated, and so it avoids stomping on any existing
 527  * mappings.
 528  */
 529 void __init early_ioremap_page_table_range_init(void)
 530 {
 531         pgd_t *pgd_base = swapper_pg_dir;
 532         unsigned long vaddr, end;
 533
 534         /*
 535          * Fixed mappings, only the page table structure has to be
 536          * created - mappings will be set by set_fixmap():
 537          */
 538         vaddr = __fix_to_virt(__end_of_fixed_addresses - 1) & PMD_MASK;
 539         end = (FIXADDR_TOP + PMD_SIZE - 1) & PMD_MASK;
 540         page_table_range_init(vaddr, end, pgd_base);
 541         early_ioremap_reset();
 542 }
 543
 544 static void __init pagetable_init(void)
 545 {
 546         pgd_t *pgd_base = swapper_pg_dir;
 547
 548         permanent_kmaps_init(pgd_base);
 549 }
 550
 551 #ifdef CONFIG_ACPI_SLEEP
 552 /*
 553  * ACPI suspend needs this for resume, because things like the intel-agp
 554  * driver might have split up a kernel 4MB mapping.
 555  */
 556 char swsusp_pg_dir[PAGE_SIZE]
 557         __attribute__ ((aligned(PAGE_SIZE)));
 558
 559 static inline void save_pg_dir(void)
 560 {
 561         memcpy(swsusp_pg_dir, swapper_pg_dir, PAGE_SIZE);
 562 }
 563 #else /* !CONFIG_ACPI_SLEEP */
 564 static inline void save_pg_dir(void)
 565 {
 566 }
 567 #endif /* !CONFIG_ACPI_SLEEP */
 568
 569 void zap_low_mappings(bool early)
 570 {
 571         int i;
 572
 573         /*
 574          * Zap initial low-memory mappings.
 575          *
 576          * Note that "pgd_clear()" doesn't do it for
 577          * us, because pgd_clear() is a no-op on i386.
 578          */
 579         for (i = 0; i < KERNEL_PGD_BOUNDARY; i++) {
 580 #ifdef CONFIG_X86_PAE
 581                 set_pgd(swapper_pg_dir+i, __pgd(1 + __pa(empty_zero_page)));
 582 #else
 583                 set_pgd(swapper_pg_dir+i, __pgd(0));
 584 #endif
 585         }
 586
 587         if (early)
 588                 __flush_tlb();
 589         else
 590                 flush_tlb_all();
 591 }
 592
 593 pteval_t __supported_pte_mask __read_mostly = ~(_PAGE_NX | _PAGE_GLOBAL | _PAGE_IOMAP);
 594 EXPORT_SYMBOL_GPL(__supported_pte_mask);
 595
 596 /* user-defined highmem size */
 597 static unsigned int highmem_pages = -1;
 598
 599 /*
 600  * highmem=size forces highmem to be exactly 'size' bytes.
 601  * This works even on boxes that have no highmem otherwise.
 602  * This also works to reduce highmem size on bigger boxes.
 603  */
 604 static int __init parse_highmem(char *arg)
 605 {
 606         if (!arg)
 607                 return -EINVAL;
 608
 609         highmem_pages = memparse(arg, &arg) >> PAGE_SHIFT;
 610         return 0;
 611 }
 612 early_param("highmem", parse_highmem);
 613
 614 #define MSG_HIGHMEM_TOO_BIG \
 615         "highmem size (%luMB) is bigger than pages available (%luMB)!\n"
 616
 617 #define MSG_LOWMEM_TOO_SMALL \
 618         "highmem size (%luMB) results in <64MB lowmem, ignoring it!\n"
 619 /*
 620  * All of RAM fits into lowmem - but if user wants highmem
 621  * artificially via the highmem=x boot parameter then create
 622  * it:
 623  */
 624 void __init lowmem_pfn_init(void)
 625 {
 626         /* max_low_pfn is 0, we already have early_res support */
 627         max_low_pfn = max_pfn;
 628
 629         if (highmem_pages == -1)
 630                 highmem_pages = 0;
 631 #ifdef CONFIG_HIGHMEM
 632         if (highmem_pages >= max_pfn) {
 633                 printk(KERN_ERR MSG_HIGHMEM_TOO_BIG,
 634                         pages_to_mb(highmem_pages), pages_to_mb(max_pfn));
 635                 highmem_pages = 0;
 636         }
 637         if (highmem_pages) {
 638                 if (max_low_pfn - highmem_pages < 64*1024*1024/PAGE_SIZE) {
 639                         printk(KERN_ERR MSG_LOWMEM_TOO_SMALL,
 640                                 pages_to_mb(highmem_pages));
 641                         highmem_pages = 0;
 642                 }
 643                 max_low_pfn -= highmem_pages;
 644         }
 645 #else
 646         if (highmem_pages)
 647                 printk(KERN_ERR "ignoring highmem size on non-highmem kernel!\n");
 648 #endif
 649 }
 650
 651 #define MSG_HIGHMEM_TOO_SMALL \
 652         "only %luMB highmem pages available, ignoring highmem size of %luMB!\n"
 653
 654 #define MSG_HIGHMEM_TRIMMED \
 655         "Warning: only 4GB will be used. Use a HIGHMEM64G enabled kernel!\n"
 656 /*
 657  * We have more RAM than fits into lowmem - we try to put it into
 658  * highmem, also taking the highmem=x boot parameter into account:
 659  */
 660 void __init highmem_pfn_init(void)
 661 {
 662         max_low_pfn = MAXMEM_PFN;
 663
 664         if (highmem_pages == -1)
 665                 highmem_pages = max_pfn - MAXMEM_PFN;
 666
 667         if (highmem_pages + MAXMEM_PFN < max_pfn)
 668                 max_pfn = MAXMEM_PFN + highmem_pages;
 669
 670         if (highmem_pages + MAXMEM_PFN > max_pfn) {
 671                 printk(KERN_WARNING MSG_HIGHMEM_TOO_SMALL,
 672                         pages_to_mb(max_pfn - MAXMEM_PFN),
 673                         pages_to_mb(highmem_pages));
 674                 highmem_pages = 0;
 675         }
 676 #ifndef CONFIG_HIGHMEM
 677         /* Maximum memory usable is what is directly addressable */
 678         printk(KERN_WARNING "Warning only %ldMB will be used.\n", MAXMEM>>20);
 679         if (max_pfn > MAX_NONPAE_PFN)
 680                 printk(KERN_WARNING "Use a HIGHMEM64G enabled kernel.\n");
 681         else
 682                 printk(KERN_WARNING "Use a HIGHMEM enabled kernel.\n");
 683         max_pfn = MAXMEM_PFN;
 684 #else /* !CONFIG_HIGHMEM */
 685 #ifndef CONFIG_HIGHMEM64G
 686         if (max_pfn > MAX_NONPAE_PFN) {
 687                 max_pfn = MAX_NONPAE_PFN;
 688                 printk(KERN_WARNING MSG_HIGHMEM_TRIMMED);
 689         }
 690 #endif /* !CONFIG_HIGHMEM64G */
 691 #endif /* !CONFIG_HIGHMEM */
 692 }
 693
 694 /*
 695  * Determine low and high memory ranges:
 696  */
 697 void __init find_low_pfn_range(void)
 698 {
 699         /* it could update max_pfn */
 700
 701         if (max_pfn <= MAXMEM_PFN)
 702                 lowmem_pfn_init();
 703         else
 704                 highmem_pfn_init();
 705 }
 706
 707 #ifndef CONFIG_NEED_MULTIPLE_NODES
 708 void __init initmem_init(unsigned long start_pfn, unsigned long end_pfn,
 709                                 int acpi, int k8)
 710 {
 711 #ifdef CONFIG_HIGHMEM
 712         highstart_pfn = highend_pfn = max_pfn;
 713         if (max_pfn > max_low_pfn)
 714                 highstart_pfn = max_low_pfn;
 715         e820_register_active_regions(0, 0, highend_pfn);
 716         sparse_memory_present_with_active_regions(0);
 717         printk(KERN_NOTICE "%ldMB HIGHMEM available.\n",
 718                 pages_to_mb(highend_pfn - highstart_pfn));
 719         num_physpages = highend_pfn;
 720         high_memory = (void *) __va(highstart_pfn * PAGE_SIZE - 1) + 1;
 721 #else
 722         e820_register_active_regions(0, 0, max_low_pfn);
 723         sparse_memory_present_with_active_regions(0);
 724         num_physpages = max_low_pfn;
 725         high_memory = (void *) __va(max_low_pfn * PAGE_SIZE - 1) + 1;
 726 #endif
 727 #ifdef CONFIG_FLATMEM
 728         max_mapnr = num_physpages;
 729 #endif
 730         __vmalloc_start_set = true;
 731
 732         printk(KERN_NOTICE "%ldMB LOWMEM available.\n",
 733                         pages_to_mb(max_low_pfn));
 734
 735         setup_bootmem_allocator();
 736 }
 737 #endif /* !CONFIG_NEED_MULTIPLE_NODES */
 738
 739 static void __init zone_sizes_init(void)
 740 {
 741         unsigned long max_zone_pfns[MAX_NR_ZONES];
 742         memset(max_zone_pfns, 0, sizeof(max_zone_pfns));
 743         max_zone_pfns[ZONE_DMA] =
 744                 virt_to_phys((char *)MAX_DMA_ADDRESS) >> PAGE_SHIFT;
 745         max_zone_pfns[ZONE_NORMAL] = max_low_pfn;
 746 #ifdef CONFIG_HIGHMEM
 747         max_zone_pfns[ZONE_HIGHMEM] = highend_pfn;
 748 #endif
 749
 750         free_area_init_nodes(max_zone_pfns);
 751 }
 752
 753 static unsigned long __init setup_node_bootmem(int nodeid,
 754                                  unsigned long start_pfn,
 755                                  unsigned long end_pfn,
 756                                  unsigned long bootmap)
 757 {
 758         unsigned long bootmap_size;
 759
 760         /* don't touch min_low_pfn */
 761         bootmap_size = init_bootmem_node(NODE_DATA(nodeid),
 762                                          bootmap >> PAGE_SHIFT,
 763                                          start_pfn, end_pfn);
 764         printk(KERN_INFO "  node %d low ram: %08lx - %08lx\n",
 765                 nodeid, start_pfn<<PAGE_SHIFT, end_pfn<<PAGE_SHIFT);
 766         printk(KERN_INFO "  node %d bootmap %08lx - %08lx\n",
 767                  nodeid, bootmap, bootmap + bootmap_size);
 768         free_bootmem_with_active_regions(nodeid, end_pfn);
 769         early_res_to_bootmem(start_pfn<<PAGE_SHIFT, end_pfn<<PAGE_SHIFT);
 770
 771         return bootmap + bootmap_size;
 772 }
 773
 774 void __init setup_bootmem_allocator(void)
 775 {
 776         int nodeid;
 777         unsigned long bootmap_size, bootmap;
 778         /*
 779          * Initialize the boot-time allocator (with low memory only):
 780          */
 781         bootmap_size = bootmem_bootmap_pages(max_low_pfn)<<PAGE_SHIFT;
 782         bootmap = find_e820_area(0, max_pfn_mapped<<PAGE_SHIFT, bootmap_size,
 783                                  PAGE_SIZE);
 784         if (bootmap == -1L)
 785                 panic("Cannot find bootmem map of size %ld\n", bootmap_size);
 786         reserve_early(bootmap, bootmap + bootmap_size, "BOOTMAP");
 787
 788         printk(KERN_INFO "  mapped low ram: 0 - %08lx\n",
 789                  max_pfn_mapped<<PAGE_SHIFT);
 790         printk(KERN_INFO "  low ram: 0 - %08lx\n", max_low_pfn<<PAGE_SHIFT);
 791
 792         for_each_online_node(nodeid) {
 793                  unsigned long start_pfn, end_pfn;
 794
 795 #ifdef CONFIG_NEED_MULTIPLE_NODES
 796                 start_pfn = node_start_pfn[nodeid];
 797                 end_pfn = node_end_pfn[nodeid];
 798                 if (start_pfn > max_low_pfn)
 799                         continue;
 800                 if (end_pfn > max_low_pfn)
 801                         end_pfn = max_low_pfn;
 802 #else
 803                 start_pfn = 0;
 804                 end_pfn = max_low_pfn;
 805 #endif
 806                 bootmap = setup_node_bootmem(nodeid, start_pfn, end_pfn,
 807                                                  bootmap);
 808         }
 809
 810         after_bootmem = 1;
 811 }
 812
 813 /*
 814  * paging_init() sets up the page tables - note that the first 8MB are
 815  * already mapped by head.S.
 816  *
 817  * This routines also unmaps the page at virtual kernel address 0, so
 818  * that we can trap those pesky NULL-reference errors in the kernel.
 819  */
 820 void __init paging_init(void)
 821 {
 822         pagetable_init();
 823
 824         __flush_tlb_all();
 825
 826         kmap_init();
 827
 828         /*
 829          * NOTE: at this point the bootmem allocator is fully available.
 830          */
 831         sparse_init();
 832         zone_sizes_init();
 833 }
 834
 835 /*
 836  * Test if the WP bit works in supervisor mode. It isn't supported on 386's
 837  * and also on some strange 486's. All 586+'s are OK. This used to involve
 838  * black magic jumps to work around some nasty CPU bugs, but fortunately the
 839  * switch to using exceptions got rid of all that.
 840  */
 841 static void __init test_wp_bit(void)
 842 {
 843         printk(KERN_INFO
 844   "Checking if this processor honours the WP bit even in supervisor mode...");
 845
 846         /* Any page-aligned address will do, the test is non-destructive */
 847         __set_fixmap(FIX_WP_TEST, __pa(&swapper_pg_dir), PAGE_READONLY);
 848         boot_cpu_data.wp_works_ok = do_test_wp_bit();
 849         clear_fixmap(FIX_WP_TEST);
 850
 851         if (!boot_cpu_data.wp_works_ok) {
 852                 printk(KERN_CONT "No.\n");
 853 #ifdef CONFIG_X86_WP_WORKS_OK
 854                 panic(
 855   "This kernel doesn't support CPU's with broken WP. Recompile it for a 386!");
 856 #endif
 857         } else {
 858                 printk(KERN_CONT "Ok.\n");
 859         }
 860 }
 861
 862 void __init mem_init(void)
 863 {
 864         int codesize, reservedpages, datasize, initsize;
 865         int tmp;
 866
 867         pci_iommu_alloc();
 868
 869 #ifdef CONFIG_FLATMEM
 870         BUG_ON(!mem_map);
 871 #endif
 872         /* this will put all low memory onto the freelists */
 873         totalram_pages += free_all_bootmem();
 874
 875         reservedpages = 0;
 876         for (tmp = 0; tmp < max_low_pfn; tmp++)
 877                 /*
 878                  * Only count reserved RAM pages:
 879                  */
 880                 if (page_is_ram(tmp) && PageReserved(pfn_to_page(tmp)))
 881                         reservedpages++;
 882
 883         set_highmem_pages_init();
 884
 885         codesize =  (unsigned long) &_etext - (unsigned long) &_text;
 886         datasize =  (unsigned long) &_edata - (unsigned long) &_etext;
 887         initsize =  (unsigned long) &__init_end - (unsigned long) &__init_begin;
 888
 889         printk(KERN_INFO "Memory: %luk/%luk available (%dk kernel code, "
 890                         "%dk reserved, %dk data, %dk init, %ldk highmem)\n",
 891                 nr_free_pages() << (PAGE_SHIFT-10),
 892                 num_physpages << (PAGE_SHIFT-10),
 893                 codesize >> 10,
 894                 reservedpages << (PAGE_SHIFT-10),
 895                 datasize >> 10,
 896                 initsize >> 10,
 897                 totalhigh_pages << (PAGE_SHIFT-10));
 898
 899         printk(KERN_INFO "virtual kernel memory layout:\n"
 900                 "    fixmap  : 0x%08lx - 0x%08lx   (%4ld kB)\n"
 901 #ifdef CONFIG_HIGHMEM
 902                 "    pkmap   : 0x%08lx - 0x%08lx   (%4ld kB)\n"
 903 #endif
 904                 "    vmalloc : 0x%08lx - 0x%08lx   (%4ld MB)\n"
 905                 "    lowmem  : 0x%08lx - 0x%08lx   (%4ld MB)\n"
 906                 "      .init : 0x%08lx - 0x%08lx   (%4ld kB)\n"
 907                 "      .data : 0x%08lx - 0x%08lx   (%4ld kB)\n"
 908                 "      .text : 0x%08lx - 0x%08lx   (%4ld kB)\n",
 909                 FIXADDR_START, FIXADDR_TOP,
 910                 (FIXADDR_TOP - FIXADDR_START) >> 10,
 911
 912 #ifdef CONFIG_HIGHMEM
 913                 PKMAP_BASE, PKMAP_BASE+LAST_PKMAP*PAGE_SIZE,
 914                 (LAST_PKMAP*PAGE_SIZE) >> 10,
 915 #endif
 916
 917                 VMALLOC_START, VMALLOC_END,
 918                 (VMALLOC_END - VMALLOC_START) >> 20,
 919
 920                 (unsigned long)__va(0), (unsigned long)high_memory,
 921                 ((unsigned long)high_memory - (unsigned long)__va(0)) >> 20,
 922
 923                 (unsigned long)&__init_begin, (unsigned long)&__init_end,
 924                 ((unsigned long)&__init_end -
 925                  (unsigned long)&__init_begin) >> 10,
 926
 927                 (unsigned long)&_etext, (unsigned long)&_edata,
 928                 ((unsigned long)&_edata - (unsigned long)&_etext) >> 10,
 929
 930                 (unsigned long)&_text, (unsigned long)&_etext,
 931                 ((unsigned long)&_etext - (unsigned long)&_text) >> 10);
 932
 933         /*
 934          * Check boundaries twice: Some fundamental inconsistencies can
 935          * be detected at build time already.
 936          */
 937 #define __FIXADDR_TOP (-PAGE_SIZE)
 938 #ifdef CONFIG_HIGHMEM
 939         BUILD_BUG_ON(PKMAP_BASE + LAST_PKMAP*PAGE_SIZE  > FIXADDR_START);
 940         BUILD_BUG_ON(VMALLOC_END                        > PKMAP_BASE);
 941 #endif
 942 #define high_memory (-128UL << 20)
 943         BUILD_BUG_ON(VMALLOC_START                      >= VMALLOC_END);
 944 #undef high_memory
 945 #undef __FIXADDR_TOP
 946
 947 #ifdef CONFIG_HIGHMEM
 948         BUG_ON(PKMAP_BASE + LAST_PKMAP*PAGE_SIZE        > FIXADDR_START);
 949         BUG_ON(VMALLOC_END                              > PKMAP_BASE);
 950 #endif
 951         BUG_ON(VMALLOC_START                            >= VMALLOC_END);
 952         BUG_ON((unsigned long)high_memory               > VMALLOC_START);
 953
 954         if (boot_cpu_data.wp_works_ok < 0)
 955                 test_wp_bit();
 956
 957         save_pg_dir();
 958         zap_low_mappings(true);
 959 }
 960
 961 #ifdef CONFIG_MEMORY_HOTPLUG
 962 int arch_add_memory(int nid, u64 start, u64 size)
 963 {
 964         struct pglist_data *pgdata = NODE_DATA(nid);
 965         struct zone *zone = pgdata->node_zones + ZONE_HIGHMEM;
 966         unsigned long start_pfn = start >> PAGE_SHIFT;
 967         unsigned long nr_pages = size >> PAGE_SHIFT;
 968
 969         return __add_pages(nid, zone, start_pfn, nr_pages);
 970 }
 971 #endif
 972
 973 /*
 974  * This function cannot be __init, since exceptions don't work in that
 975  * section.  Put this after the callers, so that it cannot be inlined.
 976  */
 977 static noinline int do_test_wp_bit(void)
 978 {
 979         char tmp_reg;
 980         int flag;
 981
 982         __asm__ __volatile__(
 983                 "       movb %0, %1     \n"
 984                 "1:     movb %1, %0     \n"
 985                 "       xorl %2, %2     \n"
 986                 "2:                     \n"
 987                 _ASM_EXTABLE(1b,2b)
 988                 :"=m" (*(char *)fix_to_virt(FIX_WP_TEST)),
 989                  "=q" (tmp_reg),
 990                  "=r" (flag)
 991                 :"2" (1)
 992                 :"memory");
 993
 994         return flag;
 995 }
 996
 997 #ifdef CONFIG_DEBUG_RODATA
 998 const int rodata_test_data = 0xC3;
 999 EXPORT_SYMBOL_GPL(rodata_test_data);
1000
1001 int kernel_set_to_readonly __read_mostly;
1002
1003 void set_kernel_text_rw(void)
1004 {
1005         unsigned long start = PFN_ALIGN(_text);
1006         unsigned long size = PFN_ALIGN(_etext) - start;
1007
1008         if (!kernel_set_to_readonly)
1009                 return;
1010
1011         pr_debug("Set kernel text: %lx - %lx for read write\n",
1012                  start, start+size);
1013
1014         set_pages_rw(virt_to_page(start), size >> PAGE_SHIFT);
1015 }
1016
1017 void set_kernel_text_ro(void)
1018 {
1019         unsigned long start = PFN_ALIGN(_text);
1020         unsigned long size = PFN_ALIGN(_etext) - start;
1021
1022         if (!kernel_set_to_readonly)
1023                 return;
1024
1025         pr_debug("Set kernel text: %lx - %lx for read only\n",
1026                  start, start+size);
1027
1028         set_pages_ro(virt_to_page(start), size >> PAGE_SHIFT);
1029 }
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         set_pages_ro(virt_to_page(start), size >> PAGE_SHIFT);
1037         printk(KERN_INFO "Write protecting the kernel text: %luk\n",
1038                 size >> 10);
1039
1040         kernel_set_to_readonly = 1;
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
1051         start += size;
1052         size = (unsigned long)__end_rodata - start;
1053         set_pages_ro(virt_to_page(start), size >> PAGE_SHIFT);
1054         printk(KERN_INFO "Write protecting the kernel read-only data: %luk\n",
1055                 size >> 10);
1056         rodata_test();
1057
1058 #ifdef CONFIG_CPA_DEBUG
1059         printk(KERN_INFO "Testing CPA: undo %lx-%lx\n", start, start + size);
1060         set_pages_rw(virt_to_page(start), size >> PAGE_SHIFT);
1061
1062         printk(KERN_INFO "Testing CPA: write protecting again\n");
1063         set_pages_ro(virt_to_page(start), size >> PAGE_SHIFT);
1064 #endif
1065 }
1066 #endif
1067
1068 int __init reserve_bootmem_generic(unsigned long phys, unsigned long len,
1069                                    int flags)
1070 {
1071         return reserve_bootmem(phys, len, flags);
1072 }