arch/ia64/mm/init.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Initialize MMU support.
   4  *
   5  * Copyright (C) 1998-2003 Hewlett-Packard Co
   6  *      David Mosberger-Tang <davidm@hpl.hp.com>
   7  */
   8 #include <linux/kernel.h>
   9 #include <linux/init.h>
  10
  11 #include <linux/bootmem.h>
  12 #include <linux/efi.h>
  13 #include <linux/elf.h>
  14 #include <linux/memblock.h>
  15 #include <linux/mm.h>
  16 #include <linux/sched/signal.h>
  17 #include <linux/mmzone.h>
  18 #include <linux/module.h>
  19 #include <linux/personality.h>
  20 #include <linux/reboot.h>
  21 #include <linux/slab.h>
  22 #include <linux/swap.h>
  23 #include <linux/proc_fs.h>
  24 #include <linux/bitops.h>
  25 #include <linux/kexec.h>
  26
  27 #include <asm/dma.h>
  28 #include <asm/io.h>
  29 #include <asm/machvec.h>
  30 #include <asm/numa.h>
  31 #include <asm/patch.h>
  32 #include <asm/pgalloc.h>
  33 #include <asm/sal.h>
  34 #include <asm/sections.h>
  35 #include <asm/tlb.h>
  36 #include <linux/uaccess.h>
  37 #include <asm/unistd.h>
  38 #include <asm/mca.h>
  39
  40 extern void ia64_tlb_init (void);
  41
  42 unsigned long MAX_DMA_ADDRESS = PAGE_OFFSET + 0x100000000UL;
  43
  44 #ifdef CONFIG_VIRTUAL_MEM_MAP
  45 unsigned long VMALLOC_END = VMALLOC_END_INIT;
  46 EXPORT_SYMBOL(VMALLOC_END);
  47 struct page *vmem_map;
  48 EXPORT_SYMBOL(vmem_map);
  49 #endif
  50
  51 struct page *zero_page_memmap_ptr;      /* map entry for zero page */
  52 EXPORT_SYMBOL(zero_page_memmap_ptr);
  53
  54 void
  55 __ia64_sync_icache_dcache (pte_t pte)
  56 {
  57         unsigned long addr;
  58         struct page *page;
  59
  60         page = pte_page(pte);
  61         addr = (unsigned long) page_address(page);
  62
  63         if (test_bit(PG_arch_1, &page->flags))
  64                 return;                         /* i-cache is already coherent with d-cache */
  65
  66         flush_icache_range(addr, addr + (PAGE_SIZE << compound_order(page)));
  67         set_bit(PG_arch_1, &page->flags);       /* mark page as clean */
  68 }
  69
  70 /*
  71  * Since DMA is i-cache coherent, any (complete) pages that were written via
  72  * DMA can be marked as "clean" so that lazy_mmu_prot_update() doesn't have to
  73  * flush them when they get mapped into an executable vm-area.
  74  */
  75 void
  76 dma_mark_clean(void *addr, size_t size)
  77 {
  78         unsigned long pg_addr, end;
  79
  80         pg_addr = PAGE_ALIGN((unsigned long) addr);
  81         end = (unsigned long) addr + size;
  82         while (pg_addr + PAGE_SIZE <= end) {
  83                 struct page *page = virt_to_page(pg_addr);
  84                 set_bit(PG_arch_1, &page->flags);
  85                 pg_addr += PAGE_SIZE;
  86         }
  87 }
  88
  89 inline void
  90 ia64_set_rbs_bot (void)
  91 {
  92         unsigned long stack_size = rlimit_max(RLIMIT_STACK) & -16;
  93
  94         if (stack_size > MAX_USER_STACK_SIZE)
  95                 stack_size = MAX_USER_STACK_SIZE;
  96         current->thread.rbs_bot = PAGE_ALIGN(current->mm->start_stack - stack_size);
  97 }
  98
  99 /*
 100  * This performs some platform-dependent address space initialization.
 101  * On IA-64, we want to setup the VM area for the register backing
 102  * store (which grows upwards) and install the gateway page which is
 103  * used for signal trampolines, etc.
 104  */
 105 void
 106 ia64_init_addr_space (void)
 107 {
 108         struct vm_area_struct *vma;
 109
 110         ia64_set_rbs_bot();
 111
 112         /*
 113          * If we're out of memory and kmem_cache_alloc() returns NULL, we simply ignore
 114          * the problem.  When the process attempts to write to the register backing store
 115          * for the first time, it will get a SEGFAULT in this case.
 116          */
 117         vma = kmem_cache_zalloc(vm_area_cachep, GFP_KERNEL);
 118         if (vma) {
 119                 INIT_LIST_HEAD(&vma->anon_vma_chain);
 120                 vma->vm_mm = current->mm;
 121                 vma->vm_start = current->thread.rbs_bot & PAGE_MASK;
 122                 vma->vm_end = vma->vm_start + PAGE_SIZE;
 123                 vma->vm_flags = VM_DATA_DEFAULT_FLAGS|VM_GROWSUP|VM_ACCOUNT;
 124                 vma->vm_page_prot = vm_get_page_prot(vma->vm_flags);
 125                 down_write(&current->mm->mmap_sem);
 126                 if (insert_vm_struct(current->mm, vma)) {
 127                         up_write(&current->mm->mmap_sem);
 128                         kmem_cache_free(vm_area_cachep, vma);
 129                         return;
 130                 }
 131                 up_write(&current->mm->mmap_sem);
 132         }
 133
 134         /* map NaT-page at address zero to speed up speculative dereferencing of NULL: */
 135         if (!(current->personality & MMAP_PAGE_ZERO)) {
 136                 vma = kmem_cache_zalloc(vm_area_cachep, GFP_KERNEL);
 137                 if (vma) {
 138                         INIT_LIST_HEAD(&vma->anon_vma_chain);
 139                         vma->vm_mm = current->mm;
 140                         vma->vm_end = PAGE_SIZE;
 141                         vma->vm_page_prot = __pgprot(pgprot_val(PAGE_READONLY) | _PAGE_MA_NAT);
 142                         vma->vm_flags = VM_READ | VM_MAYREAD | VM_IO |
 143                                         VM_DONTEXPAND | VM_DONTDUMP;
 144                         down_write(&current->mm->mmap_sem);
 145                         if (insert_vm_struct(current->mm, vma)) {
 146                                 up_write(&current->mm->mmap_sem);
 147                                 kmem_cache_free(vm_area_cachep, vma);
 148                                 return;
 149                         }
 150                         up_write(&current->mm->mmap_sem);
 151                 }
 152         }
 153 }
 154
 155 void
 156 free_initmem (void)
 157 {
 158         free_reserved_area(ia64_imva(__init_begin), ia64_imva(__init_end),
 159                            -1, "unused kernel");
 160 }
 161
 162 void __init
 163 free_initrd_mem (unsigned long start, unsigned long end)
 164 {
 165         /*
 166          * EFI uses 4KB pages while the kernel can use 4KB or bigger.
 167          * Thus EFI and the kernel may have different page sizes. It is
 168          * therefore possible to have the initrd share the same page as
 169          * the end of the kernel (given current setup).
 170          *
 171          * To avoid freeing/using the wrong page (kernel sized) we:
 172          *      - align up the beginning of initrd
 173          *      - align down the end of initrd
 174          *
 175          *  |             |
 176          *  |=============| a000
 177          *  |             |
 178          *  |             |
 179          *  |             | 9000
 180          *  |/////////////|
 181          *  |/////////////|
 182          *  |=============| 8000
 183          *  |///INITRD////|
 184          *  |/////////////|
 185          *  |/////////////| 7000
 186          *  |             |
 187          *  |KKKKKKKKKKKKK|
 188          *  |=============| 6000
 189          *  |KKKKKKKKKKKKK|
 190          *  |KKKKKKKKKKKKK|
 191          *  K=kernel using 8KB pages
 192          *
 193          * In this example, we must free page 8000 ONLY. So we must align up
 194          * initrd_start and keep initrd_end as is.
 195          */
 196         start = PAGE_ALIGN(start);
 197         end = end & PAGE_MASK;
 198
 199         if (start < end)
 200                 printk(KERN_INFO "Freeing initrd memory: %ldkB freed\n", (end - start) >> 10);
 201
 202         for (; start < end; start += PAGE_SIZE) {
 203                 if (!virt_addr_valid(start))
 204                         continue;
 205                 free_reserved_page(virt_to_page(start));
 206         }
 207 }
 208
 209 /*
 210  * This installs a clean page in the kernel's page table.
 211  */
 212 static struct page * __init
 213 put_kernel_page (struct page *page, unsigned long address, pgprot_t pgprot)
 214 {
 215         pgd_t *pgd;
 216         pud_t *pud;
 217         pmd_t *pmd;
 218         pte_t *pte;
 219
 220         pgd = pgd_offset_k(address);            /* note: this is NOT pgd_offset()! */
 221
 222         {
 223                 pud = pud_alloc(&init_mm, pgd, address);
 224                 if (!pud)
 225                         goto out;
 226                 pmd = pmd_alloc(&init_mm, pud, address);
 227                 if (!pmd)
 228                         goto out;
 229                 pte = pte_alloc_kernel(pmd, address);
 230                 if (!pte)
 231                         goto out;
 232                 if (!pte_none(*pte))
 233                         goto out;
 234                 set_pte(pte, mk_pte(page, pgprot));
 235         }
 236   out:
 237         /* no need for flush_tlb */
 238         return page;
 239 }
 240
 241 static void __init
 242 setup_gate (void)
 243 {
 244         struct page *page;
 245
 246         /*
 247          * Map the gate page twice: once read-only to export the ELF
 248          * headers etc. and once execute-only page to enable
 249          * privilege-promotion via "epc":
 250          */
 251         page = virt_to_page(ia64_imva(__start_gate_section));
 252         put_kernel_page(page, GATE_ADDR, PAGE_READONLY);
 253 #ifdef HAVE_BUGGY_SEGREL
 254         page = virt_to_page(ia64_imva(__start_gate_section + PAGE_SIZE));
 255         put_kernel_page(page, GATE_ADDR + PAGE_SIZE, PAGE_GATE);
 256 #else
 257         put_kernel_page(page, GATE_ADDR + PERCPU_PAGE_SIZE, PAGE_GATE);
 258         /* Fill in the holes (if any) with read-only zero pages: */
 259         {
 260                 unsigned long addr;
 261
 262                 for (addr = GATE_ADDR + PAGE_SIZE;
 263                      addr < GATE_ADDR + PERCPU_PAGE_SIZE;
 264                      addr += PAGE_SIZE)
 265                 {
 266                         put_kernel_page(ZERO_PAGE(0), addr,
 267                                         PAGE_READONLY);
 268                         put_kernel_page(ZERO_PAGE(0), addr + PERCPU_PAGE_SIZE,
 269                                         PAGE_READONLY);
 270                 }
 271         }
 272 #endif
 273         ia64_patch_gate();
 274 }
 275
 276 static struct vm_area_struct gate_vma;
 277
 278 static int __init gate_vma_init(void)
 279 {
 280         gate_vma.vm_mm = NULL;
 281         gate_vma.vm_start = FIXADDR_USER_START;
 282         gate_vma.vm_end = FIXADDR_USER_END;
 283         gate_vma.vm_flags = VM_READ | VM_MAYREAD | VM_EXEC | VM_MAYEXEC;
 284         gate_vma.vm_page_prot = __P101;
 285
 286         return 0;
 287 }
 288 __initcall(gate_vma_init);
 289
 290 struct vm_area_struct *get_gate_vma(struct mm_struct *mm)
 291 {
 292         return &gate_vma;
 293 }
 294
 295 int in_gate_area_no_mm(unsigned long addr)
 296 {
 297         if ((addr >= FIXADDR_USER_START) && (addr < FIXADDR_USER_END))
 298                 return 1;
 299         return 0;
 300 }
 301
 302 int in_gate_area(struct mm_struct *mm, unsigned long addr)
 303 {
 304         return in_gate_area_no_mm(addr);
 305 }
 306
 307 void ia64_mmu_init(void *my_cpu_data)
 308 {
 309         unsigned long pta, impl_va_bits;
 310         extern void tlb_init(void);
 311
 312 #ifdef CONFIG_DISABLE_VHPT
 313 #       define VHPT_ENABLE_BIT  0
 314 #else
 315 #       define VHPT_ENABLE_BIT  1
 316 #endif
 317
 318         /*
 319          * Check if the virtually mapped linear page table (VMLPT) overlaps with a mapped
 320          * address space.  The IA-64 architecture guarantees that at least 50 bits of
 321          * virtual address space are implemented but if we pick a large enough page size
 322          * (e.g., 64KB), the mapped address space is big enough that it will overlap with
 323          * VMLPT.  I assume that once we run on machines big enough to warrant 64KB pages,
 324          * IMPL_VA_MSB will be significantly bigger, so this is unlikely to become a
 325          * problem in practice.  Alternatively, we could truncate the top of the mapped
 326          * address space to not permit mappings that would overlap with the VMLPT.
 327          * --davidm 00/12/06
 328          */
 329 #       define pte_bits                 3
 330 #       define mapped_space_bits        (3*(PAGE_SHIFT - pte_bits) + PAGE_SHIFT)
 331         /*
 332          * The virtual page table has to cover the entire implemented address space within
 333          * a region even though not all of this space may be mappable.  The reason for
 334          * this is that the Access bit and Dirty bit fault handlers perform
 335          * non-speculative accesses to the virtual page table, so the address range of the
 336          * virtual page table itself needs to be covered by virtual page table.
 337          */
 338 #       define vmlpt_bits               (impl_va_bits - PAGE_SHIFT + pte_bits)
 339 #       define POW2(n)                  (1ULL << (n))
 340
 341         impl_va_bits = ffz(~(local_cpu_data->unimpl_va_mask | (7UL << 61)));
 342
 343         if (impl_va_bits < 51 || impl_va_bits > 61)
 344                 panic("CPU has bogus IMPL_VA_MSB value of %lu!\n", impl_va_bits - 1);
 345         /*
 346          * mapped_space_bits - PAGE_SHIFT is the total number of ptes we need,
 347          * which must fit into "vmlpt_bits - pte_bits" slots. Second half of
 348          * the test makes sure that our mapped space doesn't overlap the
 349          * unimplemented hole in the middle of the region.
 350          */
 351         if ((mapped_space_bits - PAGE_SHIFT > vmlpt_bits - pte_bits) ||
 352             (mapped_space_bits > impl_va_bits - 1))
 353                 panic("Cannot build a big enough virtual-linear page table"
 354                       " to cover mapped address space.\n"
 355                       " Try using a smaller page size.\n");
 356
 357
 358         /* place the VMLPT at the end of each page-table mapped region: */
 359         pta = POW2(61) - POW2(vmlpt_bits);
 360
 361         /*
 362          * Set the (virtually mapped linear) page table address.  Bit
 363          * 8 selects between the short and long format, bits 2-7 the
 364          * size of the table, and bit 0 whether the VHPT walker is
 365          * enabled.
 366          */
 367         ia64_set_pta(pta | (0 << 8) | (vmlpt_bits << 2) | VHPT_ENABLE_BIT);
 368
 369         ia64_tlb_init();
 370
 371 #ifdef  CONFIG_HUGETLB_PAGE
 372         ia64_set_rr(HPAGE_REGION_BASE, HPAGE_SHIFT << 2);
 373         ia64_srlz_d();
 374 #endif
 375 }
 376
 377 #ifdef CONFIG_VIRTUAL_MEM_MAP
 378 int vmemmap_find_next_valid_pfn(int node, int i)
 379 {
 380         unsigned long end_address, hole_next_pfn;
 381         unsigned long stop_address;
 382         pg_data_t *pgdat = NODE_DATA(node);
 383
 384         end_address = (unsigned long) &vmem_map[pgdat->node_start_pfn + i];
 385         end_address = PAGE_ALIGN(end_address);
 386         stop_address = (unsigned long) &vmem_map[pgdat_end_pfn(pgdat)];
 387
 388         do {
 389                 pgd_t *pgd;
 390                 pud_t *pud;
 391                 pmd_t *pmd;
 392                 pte_t *pte;
 393
 394                 pgd = pgd_offset_k(end_address);
 395                 if (pgd_none(*pgd)) {
 396                         end_address += PGDIR_SIZE;
 397                         continue;
 398                 }
 399
 400                 pud = pud_offset(pgd, end_address);
 401                 if (pud_none(*pud)) {
 402                         end_address += PUD_SIZE;
 403                         continue;
 404                 }
 405
 406                 pmd = pmd_offset(pud, end_address);
 407                 if (pmd_none(*pmd)) {
 408                         end_address += PMD_SIZE;
 409                         continue;
 410                 }
 411
 412                 pte = pte_offset_kernel(pmd, end_address);
 413 retry_pte:
 414                 if (pte_none(*pte)) {
 415                         end_address += PAGE_SIZE;
 416                         pte++;
 417                         if ((end_address < stop_address) &&
 418                             (end_address != ALIGN(end_address, 1UL << PMD_SHIFT)))
 419                                 goto retry_pte;
 420                         continue;
 421                 }
 422                 /* Found next valid vmem_map page */
 423                 break;
 424         } while (end_address < stop_address);
 425
 426         end_address = min(end_address, stop_address);
 427         end_address = end_address - (unsigned long) vmem_map + sizeof(struct page) - 1;
 428         hole_next_pfn = end_address / sizeof(struct page);
 429         return hole_next_pfn - pgdat->node_start_pfn;
 430 }
 431
 432 int __init create_mem_map_page_table(u64 start, u64 end, void *arg)
 433 {
 434         unsigned long address, start_page, end_page;
 435         struct page *map_start, *map_end;
 436         int node;
 437         pgd_t *pgd;
 438         pud_t *pud;
 439         pmd_t *pmd;
 440         pte_t *pte;
 441
 442         map_start = vmem_map + (__pa(start) >> PAGE_SHIFT);
 443         map_end   = vmem_map + (__pa(end) >> PAGE_SHIFT);
 444
 445         start_page = (unsigned long) map_start & PAGE_MASK;
 446         end_page = PAGE_ALIGN((unsigned long) map_end);
 447         node = paddr_to_nid(__pa(start));
 448
 449         for (address = start_page; address < end_page; address += PAGE_SIZE) {
 450                 pgd = pgd_offset_k(address);
 451                 if (pgd_none(*pgd))
 452                         pgd_populate(&init_mm, pgd, alloc_bootmem_pages_node(NODE_DATA(node), PAGE_SIZE));
 453                 pud = pud_offset(pgd, address);
 454
 455                 if (pud_none(*pud))
 456                         pud_populate(&init_mm, pud, alloc_bootmem_pages_node(NODE_DATA(node), PAGE_SIZE));
 457                 pmd = pmd_offset(pud, address);
 458
 459                 if (pmd_none(*pmd))
 460                         pmd_populate_kernel(&init_mm, pmd, alloc_bootmem_pages_node(NODE_DATA(node), PAGE_SIZE));
 461                 pte = pte_offset_kernel(pmd, address);
 462
 463                 if (pte_none(*pte))
 464                         set_pte(pte, pfn_pte(__pa(alloc_bootmem_pages_node(NODE_DATA(node), PAGE_SIZE)) >> PAGE_SHIFT,
 465                                              PAGE_KERNEL));
 466         }
 467         return 0;
 468 }
 469
 470 struct memmap_init_callback_data {
 471         struct page *start;
 472         struct page *end;
 473         int nid;
 474         unsigned long zone;
 475 };
 476
 477 static int __meminit
 478 virtual_memmap_init(u64 start, u64 end, void *arg)
 479 {
 480         struct memmap_init_callback_data *args;
 481         struct page *map_start, *map_end;
 482
 483         args = (struct memmap_init_callback_data *) arg;
 484         map_start = vmem_map + (__pa(start) >> PAGE_SHIFT);
 485         map_end   = vmem_map + (__pa(end) >> PAGE_SHIFT);
 486
 487         if (map_start < args->start)
 488                 map_start = args->start;
 489         if (map_end > args->end)
 490                 map_end = args->end;
 491
 492         /*
 493          * We have to initialize "out of bounds" struct page elements that fit completely
 494          * on the same pages that were allocated for the "in bounds" elements because they
 495          * may be referenced later (and found to be "reserved").
 496          */
 497         map_start -= ((unsigned long) map_start & (PAGE_SIZE - 1)) / sizeof(struct page);
 498         map_end += ((PAGE_ALIGN((unsigned long) map_end) - (unsigned long) map_end)
 499                     / sizeof(struct page));
 500
 501         if (map_start < map_end)
 502                 memmap_init_zone((unsigned long)(map_end - map_start),
 503                                  args->nid, args->zone, page_to_pfn(map_start),
 504                                  MEMMAP_EARLY);
 505         return 0;
 506 }
 507
 508 void __meminit
 509 memmap_init (unsigned long size, int nid, unsigned long zone,
 510              unsigned long start_pfn)
 511 {
 512         if (!vmem_map)
 513                 memmap_init_zone(size, nid, zone, start_pfn, MEMMAP_EARLY);
 514         else {
 515                 struct page *start;
 516                 struct memmap_init_callback_data args;
 517
 518                 start = pfn_to_page(start_pfn);
 519                 args.start = start;
 520                 args.end = start + size;
 521                 args.nid = nid;
 522                 args.zone = zone;
 523
 524                 efi_memmap_walk(virtual_memmap_init, &args);
 525         }
 526 }
 527
 528 int
 529 ia64_pfn_valid (unsigned long pfn)
 530 {
 531         char byte;
 532         struct page *pg = pfn_to_page(pfn);
 533
 534         return     (__get_user(byte, (char __user *) pg) == 0)
 535                 && ((((u64)pg & PAGE_MASK) == (((u64)(pg + 1) - 1) & PAGE_MASK))
 536                         || (__get_user(byte, (char __user *) (pg + 1) - 1) == 0));
 537 }
 538 EXPORT_SYMBOL(ia64_pfn_valid);
 539
 540 int __init find_largest_hole(u64 start, u64 end, void *arg)
 541 {
 542         u64 *max_gap = arg;
 543
 544         static u64 last_end = PAGE_OFFSET;
 545
 546         /* NOTE: this algorithm assumes efi memmap table is ordered */
 547
 548         if (*max_gap < (start - last_end))
 549                 *max_gap = start - last_end;
 550         last_end = end;
 551         return 0;
 552 }
 553
 554 #endif /* CONFIG_VIRTUAL_MEM_MAP */
 555
 556 int __init register_active_ranges(u64 start, u64 len, int nid)
 557 {
 558         u64 end = start + len;
 559
 560 #ifdef CONFIG_KEXEC
 561         if (start > crashk_res.start && start < crashk_res.end)
 562                 start = crashk_res.end;
 563         if (end > crashk_res.start && end < crashk_res.end)
 564                 end = crashk_res.start;
 565 #endif
 566
 567         if (start < end)
 568                 memblock_add_node(__pa(start), end - start, nid);
 569         return 0;
 570 }
 571
 572 int
 573 find_max_min_low_pfn (u64 start, u64 end, void *arg)
 574 {
 575         unsigned long pfn_start, pfn_end;
 576 #ifdef CONFIG_FLATMEM
 577         pfn_start = (PAGE_ALIGN(__pa(start))) >> PAGE_SHIFT;
 578         pfn_end = (PAGE_ALIGN(__pa(end - 1))) >> PAGE_SHIFT;
 579 #else
 580         pfn_start = GRANULEROUNDDOWN(__pa(start)) >> PAGE_SHIFT;
 581         pfn_end = GRANULEROUNDUP(__pa(end - 1)) >> PAGE_SHIFT;
 582 #endif
 583         min_low_pfn = min(min_low_pfn, pfn_start);
 584         max_low_pfn = max(max_low_pfn, pfn_end);
 585         return 0;
 586 }
 587
 588 /*
 589  * Boot command-line option "nolwsys" can be used to disable the use of any light-weight
 590  * system call handler.  When this option is in effect, all fsyscalls will end up bubbling
 591  * down into the kernel and calling the normal (heavy-weight) syscall handler.  This is
 592  * useful for performance testing, but conceivably could also come in handy for debugging
 593  * purposes.
 594  */
 595
 596 static int nolwsys __initdata;
 597
 598 static int __init
 599 nolwsys_setup (char *s)
 600 {
 601         nolwsys = 1;
 602         return 1;
 603 }
 604
 605 __setup("nolwsys", nolwsys_setup);
 606
 607 void __init
 608 mem_init (void)
 609 {
 610         int i;
 611
 612         BUG_ON(PTRS_PER_PGD * sizeof(pgd_t) != PAGE_SIZE);
 613         BUG_ON(PTRS_PER_PMD * sizeof(pmd_t) != PAGE_SIZE);
 614         BUG_ON(PTRS_PER_PTE * sizeof(pte_t) != PAGE_SIZE);
 615
 616 #ifdef CONFIG_PCI
 617         /*
 618          * This needs to be called _after_ the command line has been parsed but _before_
 619          * any drivers that may need the PCI DMA interface are initialized or bootmem has
 620          * been freed.
 621          */
 622         platform_dma_init();
 623 #endif
 624
 625 #ifdef CONFIG_FLATMEM
 626         BUG_ON(!mem_map);
 627 #endif
 628
 629         set_max_mapnr(max_low_pfn);
 630         high_memory = __va(max_low_pfn * PAGE_SIZE);
 631         free_all_bootmem();
 632         mem_init_print_info(NULL);
 633
 634         /*
 635          * For fsyscall entrpoints with no light-weight handler, use the ordinary
 636          * (heavy-weight) handler, but mark it by setting bit 0, so the fsyscall entry
 637          * code can tell them apart.
 638          */
 639         for (i = 0; i < NR_syscalls; ++i) {
 640                 extern unsigned long fsyscall_table[NR_syscalls];
 641                 extern unsigned long sys_call_table[NR_syscalls];
 642
 643                 if (!fsyscall_table[i] || nolwsys)
 644                         fsyscall_table[i] = sys_call_table[i] | 1;
 645         }
 646         setup_gate();
 647 }
 648
 649 #ifdef CONFIG_MEMORY_HOTPLUG
 650 int arch_add_memory(int nid, u64 start, u64 size, bool want_memblock)
 651 {
 652         unsigned long start_pfn = start >> PAGE_SHIFT;
 653         unsigned long nr_pages = size >> PAGE_SHIFT;
 654         int ret;
 655
 656         ret = __add_pages(nid, start_pfn, nr_pages, want_memblock);
 657         if (ret)
 658                 printk("%s: Problem encountered in __add_pages() as ret=%d\n",
 659                        __func__,  ret);
 660
 661         return ret;
 662 }
 663
 664 #ifdef CONFIG_MEMORY_HOTREMOVE
 665 int arch_remove_memory(u64 start, u64 size)
 666 {
 667         unsigned long start_pfn = start >> PAGE_SHIFT;
 668         unsigned long nr_pages = size >> PAGE_SHIFT;
 669         struct zone *zone;
 670         int ret;
 671
 672         zone = page_zone(pfn_to_page(start_pfn));
 673         ret = __remove_pages(zone, start_pfn, nr_pages);
 674         if (ret)
 675                 pr_warn("%s: Problem encountered in __remove_pages() as"
 676                         " ret=%d\n", __func__,  ret);
 677
 678         return ret;
 679 }
 680 #endif
 681 #endif