arch/ia64/mm/init.c

   1 /*
   2  * Initialize MMU support.
   3  *
   4  * Copyright (C) 1998-2003 Hewlett-Packard Co
   5  *      David Mosberger-Tang <davidm@hpl.hp.com>
   6  */
   7 #include <linux/kernel.h>
   8 #include <linux/init.h>
   9
  10 #include <linux/bootmem.h>
  11 #include <linux/efi.h>
  12 #include <linux/elf.h>
  13 #include <linux/memblock.h>
  14 #include <linux/mm.h>
  15 #include <linux/sched/signal.h>
  16 #include <linux/mmzone.h>
  17 #include <linux/module.h>
  18 #include <linux/personality.h>
  19 #include <linux/reboot.h>
  20 #include <linux/slab.h>
  21 #include <linux/swap.h>
  22 #include <linux/proc_fs.h>
  23 #include <linux/bitops.h>
  24 #include <linux/kexec.h>
  25
  26 #include <asm/dma.h>
  27 #include <asm/io.h>
  28 #include <asm/machvec.h>
  29 #include <asm/numa.h>
  30 #include <asm/patch.h>
  31 #include <asm/pgalloc.h>
  32 #include <asm/sal.h>
  33 #include <asm/sections.h>
  34 #include <asm/tlb.h>
  35 #include <linux/uaccess.h>
  36 #include <asm/unistd.h>
  37 #include <asm/mca.h>
  38
  39 extern void ia64_tlb_init (void);
  40
  41 unsigned long MAX_DMA_ADDRESS = PAGE_OFFSET + 0x100000000UL;
  42
  43 #ifdef CONFIG_VIRTUAL_MEM_MAP
  44 unsigned long VMALLOC_END = VMALLOC_END_INIT;
  45 EXPORT_SYMBOL(VMALLOC_END);
  46 struct page *vmem_map;
  47 EXPORT_SYMBOL(vmem_map);
  48 #endif
  49
  50 struct page *zero_page_memmap_ptr;      /* map entry for zero page */
  51 EXPORT_SYMBOL(zero_page_memmap_ptr);
  52
  53 void
  54 __ia64_sync_icache_dcache (pte_t pte)
  55 {
  56         unsigned long addr;
  57         struct page *page;
  58
  59         page = pte_page(pte);
  60         addr = (unsigned long) page_address(page);
  61
  62         if (test_bit(PG_arch_1, &page->flags))
  63                 return;                         /* i-cache is already coherent with d-cache */
  64
  65         flush_icache_range(addr, addr + (PAGE_SIZE << compound_order(page)));
  66         set_bit(PG_arch_1, &page->flags);       /* mark page as clean */
  67 }
  68
  69 /*
  70  * Since DMA is i-cache coherent, any (complete) pages that were written via
  71  * DMA can be marked as "clean" so that lazy_mmu_prot_update() doesn't have to
  72  * flush them when they get mapped into an executable vm-area.
  73  */
  74 void
  75 dma_mark_clean(void *addr, size_t size)
  76 {
  77         unsigned long pg_addr, end;
  78
  79         pg_addr = PAGE_ALIGN((unsigned long) addr);
  80         end = (unsigned long) addr + size;
  81         while (pg_addr + PAGE_SIZE <= end) {
  82                 struct page *page = virt_to_page(pg_addr);
  83                 set_bit(PG_arch_1, &page->flags);
  84                 pg_addr += PAGE_SIZE;
  85         }
  86 }
  87
  88 inline void
  89 ia64_set_rbs_bot (void)
  90 {
  91         unsigned long stack_size = rlimit_max(RLIMIT_STACK) & -16;
  92
  93         if (stack_size > MAX_USER_STACK_SIZE)
  94                 stack_size = MAX_USER_STACK_SIZE;
  95         current->thread.rbs_bot = PAGE_ALIGN(current->mm->start_stack - stack_size);
  96 }
  97
  98 /*
  99  * This performs some platform-dependent address space initialization.
 100  * On IA-64, we want to setup the VM area for the register backing
 101  * store (which grows upwards) and install the gateway page which is
 102  * used for signal trampolines, etc.
 103  */
 104 void
 105 ia64_init_addr_space (void)
 106 {
 107         struct vm_area_struct *vma;
 108
 109         ia64_set_rbs_bot();
 110
 111         /*
 112          * If we're out of memory and kmem_cache_alloc() returns NULL, we simply ignore
 113          * the problem.  When the process attempts to write to the register backing store
 114          * for the first time, it will get a SEGFAULT in this case.
 115          */
 116         vma = kmem_cache_zalloc(vm_area_cachep, GFP_KERNEL);
 117         if (vma) {
 118                 INIT_LIST_HEAD(&vma->anon_vma_chain);
 119                 vma->vm_mm = current->mm;
 120                 vma->vm_start = current->thread.rbs_bot & PAGE_MASK;
 121                 vma->vm_end = vma->vm_start + PAGE_SIZE;
 122                 vma->vm_flags = VM_DATA_DEFAULT_FLAGS|VM_GROWSUP|VM_ACCOUNT;
 123                 vma->vm_page_prot = vm_get_page_prot(vma->vm_flags);
 124                 down_write(&current->mm->mmap_sem);
 125                 if (insert_vm_struct(current->mm, vma)) {
 126                         up_write(&current->mm->mmap_sem);
 127                         kmem_cache_free(vm_area_cachep, vma);
 128                         return;
 129                 }
 130                 up_write(&current->mm->mmap_sem);
 131         }
 132
 133         /* map NaT-page at address zero to speed up speculative dereferencing of NULL: */
 134         if (!(current->personality & MMAP_PAGE_ZERO)) {
 135                 vma = kmem_cache_zalloc(vm_area_cachep, GFP_KERNEL);
 136                 if (vma) {
 137                         INIT_LIST_HEAD(&vma->anon_vma_chain);
 138                         vma->vm_mm = current->mm;
 139                         vma->vm_end = PAGE_SIZE;
 140                         vma->vm_page_prot = __pgprot(pgprot_val(PAGE_READONLY) | _PAGE_MA_NAT);
 141                         vma->vm_flags = VM_READ | VM_MAYREAD | VM_IO |
 142                                         VM_DONTEXPAND | VM_DONTDUMP;
 143                         down_write(&current->mm->mmap_sem);
 144                         if (insert_vm_struct(current->mm, vma)) {
 145                                 up_write(&current->mm->mmap_sem);
 146                                 kmem_cache_free(vm_area_cachep, vma);
 147                                 return;
 148                         }
 149                         up_write(&current->mm->mmap_sem);
 150                 }
 151         }
 152 }
 153
 154 void
 155 free_initmem (void)
 156 {
 157         free_reserved_area(ia64_imva(__init_begin), ia64_imva(__init_end),
 158                            -1, "unused kernel");
 159 }
 160
 161 void __init
 162 free_initrd_mem (unsigned long start, unsigned long end)
 163 {
 164         /*
 165          * EFI uses 4KB pages while the kernel can use 4KB or bigger.
 166          * Thus EFI and the kernel may have different page sizes. It is
 167          * therefore possible to have the initrd share the same page as
 168          * the end of the kernel (given current setup).
 169          *
 170          * To avoid freeing/using the wrong page (kernel sized) we:
 171          *      - align up the beginning of initrd
 172          *      - align down the end of initrd
 173          *
 174          *  |             |
 175          *  |=============| a000
 176          *  |             |
 177          *  |             |
 178          *  |             | 9000
 179          *  |/////////////|
 180          *  |/////////////|
 181          *  |=============| 8000
 182          *  |///INITRD////|
 183          *  |/////////////|
 184          *  |/////////////| 7000
 185          *  |             |
 186          *  |KKKKKKKKKKKKK|
 187          *  |=============| 6000
 188          *  |KKKKKKKKKKKKK|
 189          *  |KKKKKKKKKKKKK|
 190          *  K=kernel using 8KB pages
 191          *
 192          * In this example, we must free page 8000 ONLY. So we must align up
 193          * initrd_start and keep initrd_end as is.
 194          */
 195         start = PAGE_ALIGN(start);
 196         end = end & PAGE_MASK;
 197
 198         if (start < end)
 199                 printk(KERN_INFO "Freeing initrd memory: %ldkB freed\n", (end - start) >> 10);
 200
 201         for (; start < end; start += PAGE_SIZE) {
 202                 if (!virt_addr_valid(start))
 203                         continue;
 204                 free_reserved_page(virt_to_page(start));
 205         }
 206 }
 207
 208 /*
 209  * This installs a clean page in the kernel's page table.
 210  */
 211 static struct page * __init
 212 put_kernel_page (struct page *page, unsigned long address, pgprot_t pgprot)
 213 {
 214         pgd_t *pgd;
 215         pud_t *pud;
 216         pmd_t *pmd;
 217         pte_t *pte;
 218
 219         pgd = pgd_offset_k(address);            /* note: this is NOT pgd_offset()! */
 220
 221         {
 222                 pud = pud_alloc(&init_mm, pgd, address);
 223                 if (!pud)
 224                         goto out;
 225                 pmd = pmd_alloc(&init_mm, pud, address);
 226                 if (!pmd)
 227                         goto out;
 228                 pte = pte_alloc_kernel(pmd, address);
 229                 if (!pte)
 230                         goto out;
 231                 if (!pte_none(*pte))
 232                         goto out;
 233                 set_pte(pte, mk_pte(page, pgprot));
 234         }
 235   out:
 236         /* no need for flush_tlb */
 237         return page;
 238 }
 239
 240 static void __init
 241 setup_gate (void)
 242 {
 243         struct page *page;
 244
 245         /*
 246          * Map the gate page twice: once read-only to export the ELF
 247          * headers etc. and once execute-only page to enable
 248          * privilege-promotion via "epc":
 249          */
 250         page = virt_to_page(ia64_imva(__start_gate_section));
 251         put_kernel_page(page, GATE_ADDR, PAGE_READONLY);
 252 #ifdef HAVE_BUGGY_SEGREL
 253         page = virt_to_page(ia64_imva(__start_gate_section + PAGE_SIZE));
 254         put_kernel_page(page, GATE_ADDR + PAGE_SIZE, PAGE_GATE);
 255 #else
 256         put_kernel_page(page, GATE_ADDR + PERCPU_PAGE_SIZE, PAGE_GATE);
 257         /* Fill in the holes (if any) with read-only zero pages: */
 258         {
 259                 unsigned long addr;
 260
 261                 for (addr = GATE_ADDR + PAGE_SIZE;
 262                      addr < GATE_ADDR + PERCPU_PAGE_SIZE;
 263                      addr += PAGE_SIZE)
 264                 {
 265                         put_kernel_page(ZERO_PAGE(0), addr,
 266                                         PAGE_READONLY);
 267                         put_kernel_page(ZERO_PAGE(0), addr + PERCPU_PAGE_SIZE,
 268                                         PAGE_READONLY);
 269                 }
 270         }
 271 #endif
 272         ia64_patch_gate();
 273 }
 274
 275 static struct vm_area_struct gate_vma;
 276
 277 static int __init gate_vma_init(void)
 278 {
 279         gate_vma.vm_mm = NULL;
 280         gate_vma.vm_start = FIXADDR_USER_START;
 281         gate_vma.vm_end = FIXADDR_USER_END;
 282         gate_vma.vm_flags = VM_READ | VM_MAYREAD | VM_EXEC | VM_MAYEXEC;
 283         gate_vma.vm_page_prot = __P101;
 284
 285         return 0;
 286 }
 287 __initcall(gate_vma_init);
 288
 289 struct vm_area_struct *get_gate_vma(struct mm_struct *mm)
 290 {
 291         return &gate_vma;
 292 }
 293
 294 int in_gate_area_no_mm(unsigned long addr)
 295 {
 296         if ((addr >= FIXADDR_USER_START) && (addr < FIXADDR_USER_END))
 297                 return 1;
 298         return 0;
 299 }
 300
 301 int in_gate_area(struct mm_struct *mm, unsigned long addr)
 302 {
 303         return in_gate_area_no_mm(addr);
 304 }
 305
 306 void ia64_mmu_init(void *my_cpu_data)
 307 {
 308         unsigned long pta, impl_va_bits;
 309         extern void tlb_init(void);
 310
 311 #ifdef CONFIG_DISABLE_VHPT
 312 #       define VHPT_ENABLE_BIT  0
 313 #else
 314 #       define VHPT_ENABLE_BIT  1
 315 #endif
 316
 317         /*
 318          * Check if the virtually mapped linear page table (VMLPT) overlaps with a mapped
 319          * address space.  The IA-64 architecture guarantees that at least 50 bits of
 320          * virtual address space are implemented but if we pick a large enough page size
 321          * (e.g., 64KB), the mapped address space is big enough that it will overlap with
 322          * VMLPT.  I assume that once we run on machines big enough to warrant 64KB pages,
 323          * IMPL_VA_MSB will be significantly bigger, so this is unlikely to become a
 324          * problem in practice.  Alternatively, we could truncate the top of the mapped
 325          * address space to not permit mappings that would overlap with the VMLPT.
 326          * --davidm 00/12/06
 327          */
 328 #       define pte_bits                 3
 329 #       define mapped_space_bits        (3*(PAGE_SHIFT - pte_bits) + PAGE_SHIFT)
 330         /*
 331          * The virtual page table has to cover the entire implemented address space within
 332          * a region even though not all of this space may be mappable.  The reason for
 333          * this is that the Access bit and Dirty bit fault handlers perform
 334          * non-speculative accesses to the virtual page table, so the address range of the
 335          * virtual page table itself needs to be covered by virtual page table.
 336          */
 337 #       define vmlpt_bits               (impl_va_bits - PAGE_SHIFT + pte_bits)
 338 #       define POW2(n)                  (1ULL << (n))
 339
 340         impl_va_bits = ffz(~(local_cpu_data->unimpl_va_mask | (7UL << 61)));
 341
 342         if (impl_va_bits < 51 || impl_va_bits > 61)
 343                 panic("CPU has bogus IMPL_VA_MSB value of %lu!\n", impl_va_bits - 1);
 344         /*
 345          * mapped_space_bits - PAGE_SHIFT is the total number of ptes we need,
 346          * which must fit into "vmlpt_bits - pte_bits" slots. Second half of
 347          * the test makes sure that our mapped space doesn't overlap the
 348          * unimplemented hole in the middle of the region.
 349          */
 350         if ((mapped_space_bits - PAGE_SHIFT > vmlpt_bits - pte_bits) ||
 351             (mapped_space_bits > impl_va_bits - 1))
 352                 panic("Cannot build a big enough virtual-linear page table"
 353                       " to cover mapped address space.\n"
 354                       " Try using a smaller page size.\n");
 355
 356
 357         /* place the VMLPT at the end of each page-table mapped region: */
 358         pta = POW2(61) - POW2(vmlpt_bits);
 359
 360         /*
 361          * Set the (virtually mapped linear) page table address.  Bit
 362          * 8 selects between the short and long format, bits 2-7 the
 363          * size of the table, and bit 0 whether the VHPT walker is
 364          * enabled.
 365          */
 366         ia64_set_pta(pta | (0 << 8) | (vmlpt_bits << 2) | VHPT_ENABLE_BIT);
 367
 368         ia64_tlb_init();
 369
 370 #ifdef  CONFIG_HUGETLB_PAGE
 371         ia64_set_rr(HPAGE_REGION_BASE, HPAGE_SHIFT << 2);
 372         ia64_srlz_d();
 373 #endif
 374 }
 375
 376 #ifdef CONFIG_VIRTUAL_MEM_MAP
 377 int vmemmap_find_next_valid_pfn(int node, int i)
 378 {
 379         unsigned long end_address, hole_next_pfn;
 380         unsigned long stop_address;
 381         pg_data_t *pgdat = NODE_DATA(node);
 382
 383         end_address = (unsigned long) &vmem_map[pgdat->node_start_pfn + i];
 384         end_address = PAGE_ALIGN(end_address);
 385         stop_address = (unsigned long) &vmem_map[pgdat_end_pfn(pgdat)];
 386
 387         do {
 388                 pgd_t *pgd;
 389                 pud_t *pud;
 390                 pmd_t *pmd;
 391                 pte_t *pte;
 392
 393                 pgd = pgd_offset_k(end_address);
 394                 if (pgd_none(*pgd)) {
 395                         end_address += PGDIR_SIZE;
 396                         continue;
 397                 }
 398
 399                 pud = pud_offset(pgd, end_address);
 400                 if (pud_none(*pud)) {
 401                         end_address += PUD_SIZE;
 402                         continue;
 403                 }
 404
 405                 pmd = pmd_offset(pud, end_address);
 406                 if (pmd_none(*pmd)) {
 407                         end_address += PMD_SIZE;
 408                         continue;
 409                 }
 410
 411                 pte = pte_offset_kernel(pmd, end_address);
 412 retry_pte:
 413                 if (pte_none(*pte)) {
 414                         end_address += PAGE_SIZE;
 415                         pte++;
 416                         if ((end_address < stop_address) &&
 417                             (end_address != ALIGN(end_address, 1UL << PMD_SHIFT)))
 418                                 goto retry_pte;
 419                         continue;
 420                 }
 421                 /* Found next valid vmem_map page */
 422                 break;
 423         } while (end_address < stop_address);
 424
 425         end_address = min(end_address, stop_address);
 426         end_address = end_address - (unsigned long) vmem_map + sizeof(struct page) - 1;
 427         hole_next_pfn = end_address / sizeof(struct page);
 428         return hole_next_pfn - pgdat->node_start_pfn;
 429 }
 430
 431 int __init create_mem_map_page_table(u64 start, u64 end, void *arg)
 432 {
 433         unsigned long address, start_page, end_page;
 434         struct page *map_start, *map_end;
 435         int node;
 436         pgd_t *pgd;
 437         pud_t *pud;
 438         pmd_t *pmd;
 439         pte_t *pte;
 440
 441         map_start = vmem_map + (__pa(start) >> PAGE_SHIFT);
 442         map_end   = vmem_map + (__pa(end) >> PAGE_SHIFT);
 443
 444         start_page = (unsigned long) map_start & PAGE_MASK;
 445         end_page = PAGE_ALIGN((unsigned long) map_end);
 446         node = paddr_to_nid(__pa(start));
 447
 448         for (address = start_page; address < end_page; address += PAGE_SIZE) {
 449                 pgd = pgd_offset_k(address);
 450                 if (pgd_none(*pgd))
 451                         pgd_populate(&init_mm, pgd, alloc_bootmem_pages_node(NODE_DATA(node), PAGE_SIZE));
 452                 pud = pud_offset(pgd, address);
 453
 454                 if (pud_none(*pud))
 455                         pud_populate(&init_mm, pud, alloc_bootmem_pages_node(NODE_DATA(node), PAGE_SIZE));
 456                 pmd = pmd_offset(pud, address);
 457
 458                 if (pmd_none(*pmd))
 459                         pmd_populate_kernel(&init_mm, pmd, alloc_bootmem_pages_node(NODE_DATA(node), PAGE_SIZE));
 460                 pte = pte_offset_kernel(pmd, address);
 461
 462                 if (pte_none(*pte))
 463                         set_pte(pte, pfn_pte(__pa(alloc_bootmem_pages_node(NODE_DATA(node), PAGE_SIZE)) >> PAGE_SHIFT,
 464                                              PAGE_KERNEL));
 465         }
 466         return 0;
 467 }
 468
 469 struct memmap_init_callback_data {
 470         struct page *start;
 471         struct page *end;
 472         int nid;
 473         unsigned long zone;
 474 };
 475
 476 static int __meminit
 477 virtual_memmap_init(u64 start, u64 end, void *arg)
 478 {
 479         struct memmap_init_callback_data *args;
 480         struct page *map_start, *map_end;
 481
 482         args = (struct memmap_init_callback_data *) arg;
 483         map_start = vmem_map + (__pa(start) >> PAGE_SHIFT);
 484         map_end   = vmem_map + (__pa(end) >> PAGE_SHIFT);
 485
 486         if (map_start < args->start)
 487                 map_start = args->start;
 488         if (map_end > args->end)
 489                 map_end = args->end;
 490
 491         /*
 492          * We have to initialize "out of bounds" struct page elements that fit completely
 493          * on the same pages that were allocated for the "in bounds" elements because they
 494          * may be referenced later (and found to be "reserved").
 495          */
 496         map_start -= ((unsigned long) map_start & (PAGE_SIZE - 1)) / sizeof(struct page);
 497         map_end += ((PAGE_ALIGN((unsigned long) map_end) - (unsigned long) map_end)
 498                     / sizeof(struct page));
 499
 500         if (map_start < map_end)
 501                 memmap_init_zone((unsigned long)(map_end - map_start),
 502                                  args->nid, args->zone, page_to_pfn(map_start),
 503                                  MEMMAP_EARLY);
 504         return 0;
 505 }
 506
 507 void __meminit
 508 memmap_init (unsigned long size, int nid, unsigned long zone,
 509              unsigned long start_pfn)
 510 {
 511         if (!vmem_map)
 512                 memmap_init_zone(size, nid, zone, start_pfn, MEMMAP_EARLY);
 513         else {
 514                 struct page *start;
 515                 struct memmap_init_callback_data args;
 516
 517                 start = pfn_to_page(start_pfn);
 518                 args.start = start;
 519                 args.end = start + size;
 520                 args.nid = nid;
 521                 args.zone = zone;
 522
 523                 efi_memmap_walk(virtual_memmap_init, &args);
 524         }
 525 }
 526
 527 int
 528 ia64_pfn_valid (unsigned long pfn)
 529 {
 530         char byte;
 531         struct page *pg = pfn_to_page(pfn);
 532
 533         return     (__get_user(byte, (char __user *) pg) == 0)
 534                 && ((((u64)pg & PAGE_MASK) == (((u64)(pg + 1) - 1) & PAGE_MASK))
 535                         || (__get_user(byte, (char __user *) (pg + 1) - 1) == 0));
 536 }
 537 EXPORT_SYMBOL(ia64_pfn_valid);
 538
 539 int __init find_largest_hole(u64 start, u64 end, void *arg)
 540 {
 541         u64 *max_gap = arg;
 542
 543         static u64 last_end = PAGE_OFFSET;
 544
 545         /* NOTE: this algorithm assumes efi memmap table is ordered */
 546
 547         if (*max_gap < (start - last_end))
 548                 *max_gap = start - last_end;
 549         last_end = end;
 550         return 0;
 551 }
 552
 553 #endif /* CONFIG_VIRTUAL_MEM_MAP */
 554
 555 int __init register_active_ranges(u64 start, u64 len, int nid)
 556 {
 557         u64 end = start + len;
 558
 559 #ifdef CONFIG_KEXEC
 560         if (start > crashk_res.start && start < crashk_res.end)
 561                 start = crashk_res.end;
 562         if (end > crashk_res.start && end < crashk_res.end)
 563                 end = crashk_res.start;
 564 #endif
 565
 566         if (start < end)
 567                 memblock_add_node(__pa(start), end - start, nid);
 568         return 0;
 569 }
 570
 571 int
 572 find_max_min_low_pfn (u64 start, u64 end, void *arg)
 573 {
 574         unsigned long pfn_start, pfn_end;
 575 #ifdef CONFIG_FLATMEM
 576         pfn_start = (PAGE_ALIGN(__pa(start))) >> PAGE_SHIFT;
 577         pfn_end = (PAGE_ALIGN(__pa(end - 1))) >> PAGE_SHIFT;
 578 #else
 579         pfn_start = GRANULEROUNDDOWN(__pa(start)) >> PAGE_SHIFT;
 580         pfn_end = GRANULEROUNDUP(__pa(end - 1)) >> PAGE_SHIFT;
 581 #endif
 582         min_low_pfn = min(min_low_pfn, pfn_start);
 583         max_low_pfn = max(max_low_pfn, pfn_end);
 584         return 0;
 585 }
 586
 587 /*
 588  * Boot command-line option "nolwsys" can be used to disable the use of any light-weight
 589  * system call handler.  When this option is in effect, all fsyscalls will end up bubbling
 590  * down into the kernel and calling the normal (heavy-weight) syscall handler.  This is
 591  * useful for performance testing, but conceivably could also come in handy for debugging
 592  * purposes.
 593  */
 594
 595 static int nolwsys __initdata;
 596
 597 static int __init
 598 nolwsys_setup (char *s)
 599 {
 600         nolwsys = 1;
 601         return 1;
 602 }
 603
 604 __setup("nolwsys", nolwsys_setup);
 605
 606 void __init
 607 mem_init (void)
 608 {
 609         int i;
 610
 611         BUG_ON(PTRS_PER_PGD * sizeof(pgd_t) != PAGE_SIZE);
 612         BUG_ON(PTRS_PER_PMD * sizeof(pmd_t) != PAGE_SIZE);
 613         BUG_ON(PTRS_PER_PTE * sizeof(pte_t) != PAGE_SIZE);
 614
 615 #ifdef CONFIG_PCI
 616         /*
 617          * This needs to be called _after_ the command line has been parsed but _before_
 618          * any drivers that may need the PCI DMA interface are initialized or bootmem has
 619          * been freed.
 620          */
 621         platform_dma_init();
 622 #endif
 623
 624 #ifdef CONFIG_FLATMEM
 625         BUG_ON(!mem_map);
 626 #endif
 627
 628         set_max_mapnr(max_low_pfn);
 629         high_memory = __va(max_low_pfn * PAGE_SIZE);
 630         free_all_bootmem();
 631         mem_init_print_info(NULL);
 632
 633         /*
 634          * For fsyscall entrpoints with no light-weight handler, use the ordinary
 635          * (heavy-weight) handler, but mark it by setting bit 0, so the fsyscall entry
 636          * code can tell them apart.
 637          */
 638         for (i = 0; i < NR_syscalls; ++i) {
 639                 extern unsigned long fsyscall_table[NR_syscalls];
 640                 extern unsigned long sys_call_table[NR_syscalls];
 641
 642                 if (!fsyscall_table[i] || nolwsys)
 643                         fsyscall_table[i] = sys_call_table[i] | 1;
 644         }
 645         setup_gate();
 646 }
 647
 648 #ifdef CONFIG_MEMORY_HOTPLUG
 649 int arch_add_memory(int nid, u64 start, u64 size, bool for_device)
 650 {
 651         pg_data_t *pgdat;
 652         struct zone *zone;
 653         unsigned long start_pfn = start >> PAGE_SHIFT;
 654         unsigned long nr_pages = size >> PAGE_SHIFT;
 655         int ret;
 656
 657         pgdat = NODE_DATA(nid);
 658
 659         zone = pgdat->node_zones +
 660                 zone_for_memory(nid, start, size, ZONE_NORMAL, for_device);
 661         ret = __add_pages(nid, zone, start_pfn, nr_pages);
 662
 663         if (ret)
 664                 printk("%s: Problem encountered in __add_pages() as ret=%d\n",
 665                        __func__,  ret);
 666
 667         return ret;
 668 }
 669
 670 #ifdef CONFIG_MEMORY_HOTREMOVE
 671 int arch_remove_memory(u64 start, u64 size)
 672 {
 673         unsigned long start_pfn = start >> PAGE_SHIFT;
 674         unsigned long nr_pages = size >> PAGE_SHIFT;
 675         struct zone *zone;
 676         int ret;
 677
 678         zone = page_zone(pfn_to_page(start_pfn));
 679         ret = __remove_pages(zone, start_pfn, nr_pages);
 680         if (ret)
 681                 pr_warn("%s: Problem encountered in __remove_pages() as"
 682                         " ret=%d\n", __func__,  ret);
 683
 684         return ret;
 685 }
 686 #endif
 687 #endif