arch/i386/mm/init-xen.c

   1 /*
   2  *  linux/arch/i386/mm/init.c
   3  *
   4  *  Copyright (C) 1995  Linus Torvalds
   5  *
   6  *  Support of BIGMEM added by Gerhard Wichert, Siemens AG, July 1999
   7  */
   8
   9 #include <linux/config.h>
  10 #include <linux/module.h>
  11 #include <linux/signal.h>
  12 #include <linux/sched.h>
  13 #include <linux/kernel.h>
  14 #include <linux/errno.h>
  15 #include <linux/string.h>
  16 #include <linux/types.h>
  17 #include <linux/ptrace.h>
  18 #include <linux/mman.h>
  19 #include <linux/mm.h>
  20 #include <linux/hugetlb.h>
  21 #include <linux/swap.h>
  22 #include <linux/smp.h>
  23 #include <linux/init.h>
  24 #include <linux/highmem.h>
  25 #include <linux/pagemap.h>
  26 #include <linux/bootmem.h>
  27 #include <linux/slab.h>
  28 #include <linux/proc_fs.h>
  29 #include <linux/efi.h>
  30 #include <linux/memory_hotplug.h>
  31 #include <linux/initrd.h>
  32 #include <linux/dma-mapping.h>
  33 #include <linux/scatterlist.h>
  34
  35 #include <asm/processor.h>
  36 #include <asm/system.h>
  37 #include <asm/uaccess.h>
  38 #include <asm/pgtable.h>
  39 #include <asm/dma.h>
  40 #include <asm/fixmap.h>
  41 #include <asm/e820.h>
  42 #include <asm/apic.h>
  43 #include <asm/tlb.h>
  44 #include <asm/tlbflush.h>
  45 #include <asm/sections.h>
  46 #include <asm/hypervisor.h>
  47 #include <asm/swiotlb.h>
  48
  49 extern unsigned long *contiguous_bitmap;
  50
  51 unsigned int __VMALLOC_RESERVE = 128 << 20;
  52
  53 DEFINE_PER_CPU(struct mmu_gather, mmu_gathers);
  54 unsigned long highstart_pfn, highend_pfn;
  55
  56 static int noinline do_test_wp_bit(void);
  57
  58 /*
  59  * Creates a middle page table and puts a pointer to it in the
  60  * given global directory entry. This only returns the gd entry
  61  * in non-PAE compilation mode, since the middle layer is folded.
  62  */
  63 static pmd_t * __init one_md_table_init(pgd_t *pgd)
  64 {
  65         pud_t *pud;
  66         pmd_t *pmd_table;
  67
  68 #ifdef CONFIG_X86_PAE
  69         pmd_table = (pmd_t *) alloc_bootmem_low_pages(PAGE_SIZE);
  70         make_lowmem_page_readonly(pmd_table, XENFEAT_writable_page_tables);
  71         set_pgd(pgd, __pgd(__pa(pmd_table) | _PAGE_PRESENT));
  72         pud = pud_offset(pgd, 0);
  73         if (pmd_table != pmd_offset(pud, 0))
  74                 BUG();
  75 #else
  76         pud = pud_offset(pgd, 0);
  77         pmd_table = pmd_offset(pud, 0);
  78 #endif
  79
  80         return pmd_table;
  81 }
  82
  83 /*
  84  * Create a page table and place a pointer to it in a middle page
  85  * directory entry.
  86  */
  87 static pte_t * __init one_page_table_init(pmd_t *pmd)
  88 {
  89         if (pmd_none(*pmd)) {
  90                 pte_t *page_table = (pte_t *) alloc_bootmem_low_pages(PAGE_SIZE);
  91                 make_lowmem_page_readonly(page_table,
  92                                           XENFEAT_writable_page_tables);
  93                 set_pmd(pmd, __pmd(__pa(page_table) | _PAGE_TABLE));
  94                 if (page_table != pte_offset_kernel(pmd, 0))
  95                         BUG();
  96
  97                 return page_table;
  98         }
  99
 100         return pte_offset_kernel(pmd, 0);
 101 }
 102
 103 /*
 104  * This function initializes a certain range of kernel virtual memory
 105  * with new bootmem page tables, everywhere page tables are missing in
 106  * the given range.
 107  */
 108
 109 /*
 110  * NOTE: The pagetables are allocated contiguous on the physical space
 111  * so we can cache the place of the first one and move around without
 112  * checking the pgd every time.
 113  */
 114 static void __init page_table_range_init (unsigned long start, unsigned long end, pgd_t *pgd_base)
 115 {
 116         pgd_t *pgd;
 117         pud_t *pud;
 118         pmd_t *pmd;
 119         int pgd_idx, pmd_idx;
 120         unsigned long vaddr;
 121
 122         vaddr = start;
 123         pgd_idx = pgd_index(vaddr);
 124         pmd_idx = pmd_index(vaddr);
 125         pgd = pgd_base + pgd_idx;
 126
 127         for ( ; (pgd_idx < PTRS_PER_PGD) && (vaddr != end); pgd++, pgd_idx++) {
 128                 if (pgd_none(*pgd))
 129                         one_md_table_init(pgd);
 130                 pud = pud_offset(pgd, vaddr);
 131                 pmd = pmd_offset(pud, vaddr);
 132                 for (; (pmd_idx < PTRS_PER_PMD) && (vaddr != end); pmd++, pmd_idx++) {
 133                         if (vaddr < HYPERVISOR_VIRT_START && pmd_none(*pmd))
 134                                 one_page_table_init(pmd);
 135
 136                         vaddr += PMD_SIZE;
 137                 }
 138                 pmd_idx = 0;
 139         }
 140 }
 141
 142 static inline int is_kernel_text(unsigned long addr)
 143 {
 144         if (addr >= PAGE_OFFSET && addr <= (unsigned long)__init_end)
 145                 return 1;
 146         return 0;
 147 }
 148
 149 /*
 150  * This maps the physical memory to kernel virtual address space, a total
 151  * of max_low_pfn pages, by creating page tables starting from address
 152  * PAGE_OFFSET.
 153  */
 154 static void __init kernel_physical_mapping_init(pgd_t *pgd_base)
 155 {
 156         unsigned long pfn;
 157         pgd_t *pgd;
 158         pmd_t *pmd;
 159         pte_t *pte;
 160         int pgd_idx, pmd_idx, pte_ofs;
 161
 162         unsigned long max_ram_pfn = xen_start_info->nr_pages;
 163         if (max_ram_pfn > max_low_pfn)
 164                 max_ram_pfn = max_low_pfn;
 165
 166         pgd_idx = pgd_index(PAGE_OFFSET);
 167         pgd = pgd_base + pgd_idx;
 168         pfn = 0;
 169         pmd_idx = pmd_index(PAGE_OFFSET);
 170         pte_ofs = pte_index(PAGE_OFFSET);
 171
 172         for (; pgd_idx < PTRS_PER_PGD; pgd++, pgd_idx++) {
 173 #ifdef CONFIG_XEN
 174                 /*
 175                  * Native linux hasn't PAE-paging enabled yet at this
 176                  * point.  When running as xen domain we are in PAE
 177                  * mode already, thus we can't simply hook a empty
 178                  * pmd.  That would kill the mappings we are currently
 179                  * using ...
 180                  */
 181                 pmd = pmd_offset(pud_offset(pgd, PAGE_OFFSET), PAGE_OFFSET);
 182 #else
 183                 pmd = one_md_table_init(pgd);
 184 #endif
 185                 if (pfn >= max_low_pfn)
 186                         continue;
 187                 pmd += pmd_idx;
 188                 for (; pmd_idx < PTRS_PER_PMD && pfn < max_low_pfn; pmd++, pmd_idx++) {
 189                         unsigned int address = pfn * PAGE_SIZE + PAGE_OFFSET;
 190                         if (address >= HYPERVISOR_VIRT_START)
 191                                 continue;
 192
 193                         /* Map with big pages if possible, otherwise create normal page tables. */
 194                         if (cpu_has_pse) {
 195                                 unsigned int address2 = (pfn + PTRS_PER_PTE - 1) * PAGE_SIZE + PAGE_OFFSET + PAGE_SIZE-1;
 196
 197                                 if (is_kernel_text(address) || is_kernel_text(address2))
 198                                         set_pmd(pmd, pfn_pmd(pfn, PAGE_KERNEL_LARGE_EXEC));
 199                                 else
 200                                         set_pmd(pmd, pfn_pmd(pfn, PAGE_KERNEL_LARGE));
 201                                 pfn += PTRS_PER_PTE;
 202                         } else {
 203                                 pte = one_page_table_init(pmd);
 204
 205                                 pte += pte_ofs;
 206                                 for (; pte_ofs < PTRS_PER_PTE && pfn < max_low_pfn; pte++, pfn++, pte_ofs++) {
 207                                                 /* XEN: Only map initial RAM allocation. */
 208                                                 if ((pfn >= max_ram_pfn) || pte_present(*pte))
 209                                                         continue;
 210                                                 if (is_kernel_text(address))
 211                                                         set_pte(pte, pfn_pte(pfn, PAGE_KERNEL_EXEC));
 212                                                 else
 213                                                         set_pte(pte, pfn_pte(pfn, PAGE_KERNEL));
 214                                 }
 215                                 pte_ofs = 0;
 216                         }
 217                 }
 218                 pmd_idx = 0;
 219         }
 220 }
 221
 222 #ifndef CONFIG_XEN
 223
 224 static inline int page_kills_ppro(unsigned long pagenr)
 225 {
 226         if (pagenr >= 0x70000 && pagenr <= 0x7003F)
 227                 return 1;
 228         return 0;
 229 }
 230
 231 extern int is_available_memory(efi_memory_desc_t *);
 232
 233 int page_is_ram(unsigned long pagenr)
 234 {
 235         int i;
 236         unsigned long addr, end;
 237
 238         if (efi_enabled) {
 239                 efi_memory_desc_t *md;
 240                 void *p;
 241
 242                 for (p = memmap.map; p < memmap.map_end; p += memmap.desc_size) {
 243                         md = p;
 244                         if (!is_available_memory(md))
 245                                 continue;
 246                         addr = (md->phys_addr+PAGE_SIZE-1) >> PAGE_SHIFT;
 247                         end = (md->phys_addr + (md->num_pages << EFI_PAGE_SHIFT)) >> PAGE_SHIFT;
 248
 249                         if ((pagenr >= addr) && (pagenr < end))
 250                                 return 1;
 251                 }
 252                 return 0;
 253         }
 254
 255         for (i = 0; i < e820.nr_map; i++) {
 256
 257                 if (e820.map[i].type != E820_RAM)       /* not usable memory */
 258                         continue;
 259                 /*
 260                  *      !!!FIXME!!! Some BIOSen report areas as RAM that
 261                  *      are not. Notably the 640->1Mb area. We need a sanity
 262                  *      check here.
 263                  */
 264                 addr = (e820.map[i].addr+PAGE_SIZE-1) >> PAGE_SHIFT;
 265                 end = (e820.map[i].addr+e820.map[i].size) >> PAGE_SHIFT;
 266                 if  ((pagenr >= addr) && (pagenr < end))
 267                         return 1;
 268         }
 269         return 0;
 270 }
 271
 272 #else /* CONFIG_XEN */
 273
 274 #define page_kills_ppro(p)      0
 275 #define page_is_ram(p)          1
 276
 277 #endif
 278
 279 #ifdef CONFIG_HIGHMEM
 280 pte_t *kmap_pte;
 281 pgprot_t kmap_prot;
 282
 283 #define kmap_get_fixmap_pte(vaddr)                                      \
 284         pte_offset_kernel(pmd_offset(pud_offset(pgd_offset_k(vaddr), vaddr), (vaddr)), (vaddr))
 285
 286 static void __init kmap_init(void)
 287 {
 288         unsigned long kmap_vstart;
 289
 290         /* cache the first kmap pte */
 291         kmap_vstart = __fix_to_virt(FIX_KMAP_BEGIN);
 292         kmap_pte = kmap_get_fixmap_pte(kmap_vstart);
 293
 294         kmap_prot = PAGE_KERNEL;
 295 }
 296
 297 static void __init permanent_kmaps_init(pgd_t *pgd_base)
 298 {
 299         pgd_t *pgd;
 300         pud_t *pud;
 301         pmd_t *pmd;
 302         pte_t *pte;
 303         unsigned long vaddr;
 304
 305         vaddr = PKMAP_BASE;
 306         page_table_range_init(vaddr, vaddr + PAGE_SIZE*LAST_PKMAP, pgd_base);
 307
 308         pgd = swapper_pg_dir + pgd_index(vaddr);
 309         pud = pud_offset(pgd, vaddr);
 310         pmd = pmd_offset(pud, vaddr);
 311         pte = pte_offset_kernel(pmd, vaddr);
 312         pkmap_page_table = pte;
 313 }
 314
 315 static void __meminit free_new_highpage(struct page *page, int pfn)
 316 {
 317         set_page_count(page, 1);
 318         if (pfn < xen_start_info->nr_pages)
 319                 __free_page(page);
 320         totalhigh_pages++;
 321 }
 322
 323 void __init add_one_highpage_init(struct page *page, int pfn, int bad_ppro)
 324 {
 325         if (page_is_ram(pfn) && !(bad_ppro && page_kills_ppro(pfn))) {
 326                 ClearPageReserved(page);
 327                 free_new_highpage(page, pfn);
 328         } else
 329                 SetPageReserved(page);
 330 }
 331
 332 static int add_one_highpage_hotplug(struct page *page, unsigned long pfn)
 333 {
 334         free_new_highpage(page, pfn);
 335         totalram_pages++;
 336 #ifdef CONFIG_FLATMEM
 337         max_mapnr = max(pfn, max_mapnr);
 338 #endif
 339         num_physpages++;
 340         return 0;
 341 }
 342
 343 /*
 344  * Not currently handling the NUMA case.
 345  * Assuming single node and all memory that
 346  * has been added dynamically that would be
 347  * onlined here is in HIGHMEM
 348  */
 349 void online_page(struct page *page)
 350 {
 351         ClearPageReserved(page);
 352         add_one_highpage_hotplug(page, page_to_pfn(page));
 353 }
 354
 355
 356 #ifdef CONFIG_NUMA
 357 extern void set_highmem_pages_init(int);
 358 #else
 359 static void __init set_highmem_pages_init(int bad_ppro)
 360 {
 361         int pfn;
 362         for (pfn = highstart_pfn; pfn < highend_pfn; pfn++)
 363                 add_one_highpage_init(pfn_to_page(pfn), pfn, bad_ppro);
 364         totalram_pages += totalhigh_pages;
 365 }
 366 #endif /* CONFIG_FLATMEM */
 367
 368 #else
 369 #define kmap_init() do { } while (0)
 370 #define permanent_kmaps_init(pgd_base) do { } while (0)
 371 #define set_highmem_pages_init(bad_ppro) do { } while (0)
 372 #endif /* CONFIG_HIGHMEM */
 373
 374 unsigned long long __PAGE_KERNEL = _PAGE_KERNEL;
 375 EXPORT_SYMBOL(__PAGE_KERNEL);
 376 unsigned long long __PAGE_KERNEL_EXEC = _PAGE_KERNEL_EXEC;
 377
 378 #ifdef CONFIG_NUMA
 379 extern void __init remap_numa_kva(void);
 380 #else
 381 #define remap_numa_kva() do {} while (0)
 382 #endif
 383
 384 pgd_t *swapper_pg_dir;
 385
 386 static void __init pagetable_init (void)
 387 {
 388         unsigned long vaddr;
 389         pgd_t *pgd_base = (pgd_t *)xen_start_info->pt_base;
 390
 391         swapper_pg_dir = pgd_base;
 392         init_mm.pgd    = pgd_base;
 393
 394         /* Enable PSE if available */
 395         if (cpu_has_pse) {
 396                 set_in_cr4(X86_CR4_PSE);
 397         }
 398
 399         /* Enable PGE if available */
 400         if (cpu_has_pge) {
 401                 set_in_cr4(X86_CR4_PGE);
 402                 __PAGE_KERNEL |= _PAGE_GLOBAL;
 403                 __PAGE_KERNEL_EXEC |= _PAGE_GLOBAL;
 404         }
 405
 406         kernel_physical_mapping_init(pgd_base);
 407         remap_numa_kva();
 408
 409         /*
 410          * Fixed mappings, only the page table structure has to be
 411          * created - mappings will be set by set_fixmap():
 412          */
 413         vaddr = __fix_to_virt(__end_of_fixed_addresses - 1) & PMD_MASK;
 414         page_table_range_init(vaddr, 0, pgd_base);
 415
 416         permanent_kmaps_init(pgd_base);
 417 }
 418
 419 #ifdef CONFIG_SOFTWARE_SUSPEND
 420 /*
 421  * Swap suspend & friends need this for resume because things like the intel-agp
 422  * driver might have split up a kernel 4MB mapping.
 423  */
 424 char __nosavedata swsusp_pg_dir[PAGE_SIZE]
 425         __attribute__ ((aligned (PAGE_SIZE)));
 426
 427 static inline void save_pg_dir(void)
 428 {
 429         memcpy(swsusp_pg_dir, swapper_pg_dir, PAGE_SIZE);
 430 }
 431 #else
 432 static inline void save_pg_dir(void)
 433 {
 434 }
 435 #endif
 436
 437 void zap_low_mappings (void)
 438 {
 439         int i;
 440
 441         save_pg_dir();
 442
 443         /*
 444          * Zap initial low-memory mappings.
 445          *
 446          * Note that "pgd_clear()" doesn't do it for
 447          * us, because pgd_clear() is a no-op on i386.
 448          */
 449         for (i = 0; i < USER_PTRS_PER_PGD; i++)
 450 #if defined(CONFIG_X86_PAE) && !defined(CONFIG_XEN)
 451                 set_pgd(swapper_pg_dir+i, __pgd(1 + __pa(empty_zero_page)));
 452 #else
 453                 set_pgd(swapper_pg_dir+i, __pgd(0));
 454 #endif
 455         flush_tlb_all();
 456 }
 457
 458 static int disable_nx __initdata = 0;
 459 u64 __supported_pte_mask __read_mostly = ~_PAGE_NX;
 460 EXPORT_SYMBOL(__supported_pte_mask);
 461
 462 /*
 463  * noexec = on|off
 464  *
 465  * Control non executable mappings.
 466  *
 467  * on      Enable
 468  * off     Disable
 469  */
 470 void __init noexec_setup(const char *str)
 471 {
 472         if (!strncmp(str, "on",2) && cpu_has_nx) {
 473                 __supported_pte_mask |= _PAGE_NX;
 474                 disable_nx = 0;
 475         } else if (!strncmp(str,"off",3)) {
 476                 disable_nx = 1;
 477                 __supported_pte_mask &= ~_PAGE_NX;
 478         }
 479 }
 480
 481 int nx_enabled = 0;
 482 #ifdef CONFIG_X86_PAE
 483
 484 static void __init set_nx(void)
 485 {
 486         unsigned int v[4], l, h;
 487
 488         if (cpu_has_pae && (cpuid_eax(0x80000000) > 0x80000001)) {
 489                 cpuid(0x80000001, &v[0], &v[1], &v[2], &v[3]);
 490                 if ((v[3] & (1 << 20)) && !disable_nx) {
 491                         rdmsr(MSR_EFER, l, h);
 492                         l |= EFER_NX;
 493                         wrmsr(MSR_EFER, l, h);
 494                         nx_enabled = 1;
 495                         __supported_pte_mask |= _PAGE_NX;
 496                 }
 497         }
 498 }
 499
 500 /*
 501  * Enables/disables executability of a given kernel page and
 502  * returns the previous setting.
 503  */
 504 int __init set_kernel_exec(unsigned long vaddr, int enable)
 505 {
 506         pte_t *pte;
 507         int ret = 1;
 508
 509         if (!nx_enabled)
 510                 goto out;
 511
 512         pte = lookup_address(vaddr);
 513         BUG_ON(!pte);
 514
 515         if (!pte_exec_kernel(*pte))
 516                 ret = 0;
 517
 518         if (enable)
 519                 pte->pte_high &= ~(1 << (_PAGE_BIT_NX - 32));
 520         else
 521                 pte->pte_high |= 1 << (_PAGE_BIT_NX - 32);
 522         __flush_tlb_all();
 523 out:
 524         return ret;
 525 }
 526
 527 #endif
 528
 529 /*
 530  * paging_init() sets up the page tables - note that the first 8MB are
 531  * already mapped by head.S.
 532  *
 533  * This routines also unmaps the page at virtual kernel address 0, so
 534  * that we can trap those pesky NULL-reference errors in the kernel.
 535  */
 536 void __init paging_init(void)
 537 {
 538         int i;
 539
 540 #ifdef CONFIG_X86_PAE
 541         set_nx();
 542         if (nx_enabled)
 543                 printk("NX (Execute Disable) protection: active\n");
 544 #endif
 545
 546         pagetable_init();
 547
 548 #if defined(CONFIG_X86_PAE) && !defined(CONFIG_XEN)
 549         /*
 550          * We will bail out later - printk doesn't work right now so
 551          * the user would just see a hanging kernel.
 552          * when running as xen domain we are already in PAE mode at
 553          * this point.
 554          */
 555         if (cpu_has_pae)
 556                 set_in_cr4(X86_CR4_PAE);
 557 #endif
 558         __flush_tlb_all();
 559
 560         kmap_init();
 561
 562         if (!xen_feature(XENFEAT_auto_translated_physmap) ||
 563             xen_start_info->shared_info >= xen_start_info->nr_pages) {
 564                 /* Switch to the real shared_info page, and clear the
 565                  * dummy page. */
 566                 set_fixmap(FIX_SHARED_INFO, xen_start_info->shared_info);
 567                 HYPERVISOR_shared_info =
 568                         (shared_info_t *)fix_to_virt(FIX_SHARED_INFO);
 569                 memset(empty_zero_page, 0, sizeof(empty_zero_page));
 570         }
 571
 572         /* Setup mapping of lower 1st MB */
 573         for (i = 0; i < NR_FIX_ISAMAPS; i++)
 574                 if (xen_start_info->flags & SIF_PRIVILEGED)
 575                         set_fixmap(FIX_ISAMAP_BEGIN - i, i * PAGE_SIZE);
 576                 else
 577                         __set_fixmap(FIX_ISAMAP_BEGIN - i,
 578                                      virt_to_machine(empty_zero_page),
 579                                      PAGE_KERNEL_RO);
 580 }
 581
 582 /*
 583  * Test if the WP bit works in supervisor mode. It isn't supported on 386's
 584  * and also on some strange 486's (NexGen etc.). All 586+'s are OK. This
 585  * used to involve black magic jumps to work around some nasty CPU bugs,
 586  * but fortunately the switch to using exceptions got rid of all that.
 587  */
 588
 589 static void __init test_wp_bit(void)
 590 {
 591         printk("Checking if this processor honours the WP bit even in supervisor mode... ");
 592
 593         /* Any page-aligned address will do, the test is non-destructive */
 594         __set_fixmap(FIX_WP_TEST, __pa(&swapper_pg_dir), PAGE_READONLY);
 595         boot_cpu_data.wp_works_ok = do_test_wp_bit();
 596         clear_fixmap(FIX_WP_TEST);
 597
 598         if (!boot_cpu_data.wp_works_ok) {
 599                 printk("No.\n");
 600 #ifdef CONFIG_X86_WP_WORKS_OK
 601                 panic("This kernel doesn't support CPU's with broken WP. Recompile it for a 386!");
 602 #endif
 603         } else {
 604                 printk("Ok.\n");
 605         }
 606 }
 607
 608 static void __init set_max_mapnr_init(void)
 609 {
 610 #ifdef CONFIG_HIGHMEM
 611         num_physpages = highend_pfn;
 612 #else
 613         num_physpages = max_low_pfn;
 614 #endif
 615 #ifdef CONFIG_FLATMEM
 616         max_mapnr = num_physpages;
 617 #endif
 618 }
 619
 620 static struct kcore_list kcore_mem, kcore_vmalloc;
 621
 622 void __init mem_init(void)
 623 {
 624         extern int ppro_with_ram_bug(void);
 625         int codesize, reservedpages, datasize, initsize;
 626         int tmp;
 627         int bad_ppro;
 628         unsigned long pfn;
 629
 630         contiguous_bitmap = alloc_bootmem_low_pages(
 631                 (max_low_pfn + 2*BITS_PER_LONG) >> 3);
 632         BUG_ON(!contiguous_bitmap);
 633         memset(contiguous_bitmap, 0, (max_low_pfn + 2*BITS_PER_LONG) >> 3);
 634
 635 #if defined(CONFIG_SWIOTLB)
 636         swiotlb_init();
 637 #endif
 638
 639 #ifdef CONFIG_FLATMEM
 640         if (!mem_map)
 641                 BUG();
 642 #endif
 643
 644         bad_ppro = ppro_with_ram_bug();
 645
 646 #ifdef CONFIG_HIGHMEM
 647         /* check that fixmap and pkmap do not overlap */
 648         if (PKMAP_BASE+LAST_PKMAP*PAGE_SIZE >= FIXADDR_START) {
 649                 printk(KERN_ERR "fixmap and kmap areas overlap - this will crash\n");
 650                 printk(KERN_ERR "pkstart: %lxh pkend: %lxh fixstart %lxh\n",
 651                                 PKMAP_BASE, PKMAP_BASE+LAST_PKMAP*PAGE_SIZE, FIXADDR_START);
 652                 BUG();
 653         }
 654 #endif
 655
 656         set_max_mapnr_init();
 657
 658 #ifdef CONFIG_HIGHMEM
 659         high_memory = (void *) __va(highstart_pfn * PAGE_SIZE - 1) + 1;
 660 #else
 661         high_memory = (void *) __va(max_low_pfn * PAGE_SIZE - 1) + 1;
 662 #endif
 663         printk("vmalloc area: %lx-%lx, maxmem %lx\n",
 664                VMALLOC_START,VMALLOC_END,MAXMEM);
 665         BUG_ON(VMALLOC_START > VMALLOC_END);
 666
 667         /* this will put all low memory onto the freelists */
 668         totalram_pages += free_all_bootmem();
 669         /* XEN: init and count low-mem pages outside initial allocation. */
 670         for (pfn = xen_start_info->nr_pages; pfn < max_low_pfn; pfn++) {
 671                 ClearPageReserved(&mem_map[pfn]);
 672                 set_page_count(&mem_map[pfn], 1);
 673                 totalram_pages++;
 674         }
 675
 676         reservedpages = 0;
 677         for (tmp = 0; tmp < max_low_pfn; tmp++)
 678                 /*
 679                  * Only count reserved RAM pages
 680                  */
 681                 if (page_is_ram(tmp) && PageReserved(pfn_to_page(tmp)))
 682                         reservedpages++;
 683
 684         set_highmem_pages_init(bad_ppro);
 685
 686         codesize =  (unsigned long) &_etext - (unsigned long) &_text;
 687         datasize =  (unsigned long) &_edata - (unsigned long) &_etext;
 688         initsize =  (unsigned long) &__init_end - (unsigned long) &__init_begin;
 689
 690         kclist_add(&kcore_mem, __va(0), max_low_pfn << PAGE_SHIFT);
 691         kclist_add(&kcore_vmalloc, (void *)VMALLOC_START,
 692                    VMALLOC_END-VMALLOC_START);
 693
 694         printk(KERN_INFO "Memory: %luk/%luk available (%dk kernel code, %dk reserved, %dk data, %dk init, %ldk highmem)\n",
 695                 (unsigned long) nr_free_pages() << (PAGE_SHIFT-10),
 696                 num_physpages << (PAGE_SHIFT-10),
 697                 codesize >> 10,
 698                 reservedpages << (PAGE_SHIFT-10),
 699                 datasize >> 10,
 700                 initsize >> 10,
 701                 (unsigned long) (totalhigh_pages << (PAGE_SHIFT-10))
 702                );
 703
 704 #ifdef CONFIG_X86_PAE
 705         if (!cpu_has_pae)
 706                 panic("cannot execute a PAE-enabled kernel on a PAE-less CPU!");
 707 #endif
 708         if (boot_cpu_data.wp_works_ok < 0)
 709                 test_wp_bit();
 710
 711         /*
 712          * Subtle. SMP is doing it's boot stuff late (because it has to
 713          * fork idle threads) - but it also needs low mappings for the
 714          * protected-mode entry to work. We zap these entries only after
 715          * the WP-bit has been tested.
 716          */
 717 #ifndef CONFIG_SMP
 718         zap_low_mappings();
 719 #endif
 720
 721         set_bit(PG_pinned, &virt_to_page(init_mm.pgd)->flags);
 722 }
 723
 724 /*
 725  * this is for the non-NUMA, single node SMP system case.
 726  * Specifically, in the case of x86, we will always add
 727  * memory to the highmem for now.
 728  */
 729 #ifndef CONFIG_NEED_MULTIPLE_NODES
 730 int add_memory(u64 start, u64 size)
 731 {
 732         struct pglist_data *pgdata = &contig_page_data;
 733         struct zone *zone = pgdata->node_zones + MAX_NR_ZONES-1;
 734         unsigned long start_pfn = start >> PAGE_SHIFT;
 735         unsigned long nr_pages = size >> PAGE_SHIFT;
 736
 737         return __add_pages(zone, start_pfn, nr_pages);
 738 }
 739
 740 int remove_memory(u64 start, u64 size)
 741 {
 742         return -EINVAL;
 743 }
 744 #endif
 745
 746 kmem_cache_t *pgd_cache;
 747 kmem_cache_t *pmd_cache;
 748
 749 void __init pgtable_cache_init(void)
 750 {
 751         if (PTRS_PER_PMD > 1) {
 752                 pmd_cache = kmem_cache_create("pmd",
 753                                         PTRS_PER_PMD*sizeof(pmd_t),
 754                                         PTRS_PER_PMD*sizeof(pmd_t),
 755                                         0,
 756                                         pmd_ctor,
 757                                         NULL);
 758                 if (!pmd_cache)
 759                         panic("pgtable_cache_init(): cannot create pmd cache");
 760         }
 761         pgd_cache = kmem_cache_create("pgd",
 762 #ifndef CONFIG_XEN
 763                                 PTRS_PER_PGD*sizeof(pgd_t),
 764                                 PTRS_PER_PGD*sizeof(pgd_t),
 765 #else
 766                                 PAGE_SIZE,
 767                                 PAGE_SIZE,
 768 #endif
 769                                 0,
 770                                 pgd_ctor,
 771                                 pgd_dtor);
 772         if (!pgd_cache)
 773                 panic("pgtable_cache_init(): Cannot create pgd cache");
 774 }
 775
 776 /*
 777  * This function cannot be __init, since exceptions don't work in that
 778  * section.  Put this after the callers, so that it cannot be inlined.
 779  */
 780 static int noinline do_test_wp_bit(void)
 781 {
 782         char tmp_reg;
 783         int flag;
 784
 785         __asm__ __volatile__(
 786                 "       movb %0,%1      \n"
 787                 "1:     movb %1,%0      \n"
 788                 "       xorl %2,%2      \n"
 789                 "2:                     \n"
 790                 ".section __ex_table,\"a\"\n"
 791                 "       .align 4        \n"
 792                 "       .long 1b,2b     \n"
 793                 ".previous              \n"
 794                 :"=m" (*(char *)fix_to_virt(FIX_WP_TEST)),
 795                  "=q" (tmp_reg),
 796                  "=r" (flag)
 797                 :"2" (1)
 798                 :"memory");
 799
 800         return flag;
 801 }
 802
 803 void free_initmem(void)
 804 {
 805         unsigned long addr;
 806
 807         addr = (unsigned long)(&__init_begin);
 808         for (; addr < (unsigned long)(&__init_end); addr += PAGE_SIZE) {
 809                 ClearPageReserved(virt_to_page(addr));
 810                 set_page_count(virt_to_page(addr), 1);
 811                 memset((void *)addr, 0xcc, PAGE_SIZE);
 812                 free_page(addr);
 813                 totalram_pages++;
 814         }
 815         printk (KERN_INFO "Freeing unused kernel memory: %dk freed\n", (__init_end - __init_begin) >> 10);
 816 }
 817
 818 #ifdef CONFIG_DEBUG_RODATA
 819
 820 extern char __start_rodata, __end_rodata;
 821 void mark_rodata_ro(void)
 822 {
 823         unsigned long addr = (unsigned long)&__start_rodata;
 824
 825         for (; addr < (unsigned long)&__end_rodata; addr += PAGE_SIZE)
 826                 change_page_attr(virt_to_page(addr), 1, PAGE_KERNEL_RO);
 827
 828         printk ("Write protecting the kernel read-only data: %luk\n",
 829                         (unsigned long)(&__end_rodata - &__start_rodata) >> 10);
 830
 831         /*
 832          * change_page_attr() requires a global_flush_tlb() call after it.
 833          * We do this after the printk so that if something went wrong in the
 834          * change, the printk gets out at least to give a better debug hint
 835          * of who is the culprit.
 836          */
 837         global_flush_tlb();
 838 }
 839 #endif
 840
 841
 842 #ifdef CONFIG_BLK_DEV_INITRD
 843 void free_initrd_mem(unsigned long start, unsigned long end)
 844 {
 845         if (start < end)
 846                 printk (KERN_INFO "Freeing initrd memory: %ldk freed\n", (end - start) >> 10);
 847         for (; start < end; start += PAGE_SIZE) {
 848                 ClearPageReserved(virt_to_page(start));
 849                 set_page_count(virt_to_page(start), 1);
 850                 free_page(start);
 851                 totalram_pages++;
 852         }
 853 }
 854 #endif