text: /*
   * Initialize MMU support.
   *
   * Copyright (C) 1998-2003 Hewlett-Packard Co
   *	David Mosberger-Tang <davidm@hpl.hp.com>
   */
  #include <linux/kernel.h>
  #include <linux/init.h>
  
  #include <linux/bootmem.h>
  #include <linux/efi.h>
  #include <linux/elf.h>
  #include <linux/memblock.h>
  #include <linux/mm.h>
  #include <linux/mmzone.h>
  #include <linux/module.h>
  #include <linux/personality.h>
  #include <linux/reboot.h>
  #include <linux/slab.h>
  #include <linux/swap.h>
  #include <linux/proc_fs.h>
  #include <linux/bitops.h>
  #include <linux/kexec.h>
  
  #include <asm/dma.h>
  #include <asm/io.h>
  #include <asm/machvec.h>
  #include <asm/numa.h>
  #include <asm/patch.h>
  #include <asm/pgalloc.h>
  #include <asm/sal.h>
  #include <asm/sections.h>
  #include <asm/tlb.h>
  #include <asm/uaccess.h>
  #include <asm/unistd.h>
  #include <asm/mca.h>
  #include <asm/paravirt.h>
  
  extern void ia64_tlb_init (void);
  
  unsigned long MAX_DMA_ADDRESS = PAGE_OFFSET + 0x100000000UL;
  
  #ifdef CONFIG_VIRTUAL_MEM_MAP
  unsigned long VMALLOC_END = VMALLOC_END_INIT;
  EXPORT_SYMBOL(VMALLOC_END);
  struct page *vmem_map;
  EXPORT_SYMBOL(vmem_map);
  #endif
  
  struct page *zero_page_memmap_ptr;	/* map entry for zero page */
  EXPORT_SYMBOL(zero_page_memmap_ptr);
  
  void
  __ia64_sync_icache_dcache (pte_t pte)
  {
  	unsigned long addr;
  	struct page *page;
  
  	page = pte_page(pte);
  	addr = (unsigned long) page_address(page);
  
  	if (test_bit(PG_arch_1, &page->flags))
  		return;				/* i-cache is already coherent with d-cache */
  
  	flush_icache_range(addr, addr + (PAGE_SIZE << compound_order(page)));
  	set_bit(PG_arch_1, &page->flags);	/* mark page as clean */
  }
  
  /*
   * Since DMA is i-cache coherent, any (complete) pages that were written via
   * DMA can be marked as "clean" so that lazy_mmu_prot_update() doesn't have to
   * flush them when they get mapped into an executable vm-area.
   */
  void
  dma_mark_clean(void *addr, size_t size)
  {
  	unsigned long pg_addr, end;
  
  	pg_addr = PAGE_ALIGN((unsigned long) addr);
  	end = (unsigned long) addr + size;
  	while (pg_addr + PAGE_SIZE <= end) {
  		struct page *page = virt_to_page(pg_addr);
  		set_bit(PG_arch_1, &page->flags);
  		pg_addr += PAGE_SIZE;
  	}
  }
  
  inline void
  ia64_set_rbs_bot (void)
  {
  	unsigned long stack_size = rlimit_max(RLIMIT_STACK) & -16;
  
  	if (stack_size > MAX_USER_STACK_SIZE)
  		stack_size = MAX_USER_STACK_SIZE;
  	current->thread.rbs_bot = PAGE_ALIGN(current->mm->start_stack - stack_size);
  }
  
  /*
   * This performs some platform-dependent address space initialization.
   * On IA-64, we want to setup the VM area for the register backing
   * store (which grows upwards) and install the gateway page which is
   * used for signal trampolines, etc.
   */
  void
  ia64_init_addr_space (void)
  {
  	struct vm_area_struct *vma;
  
  	ia64_set_rbs_bot();
  
  	/*
  	 * If we're out of memory and kmem_cache_alloc() returns NULL, we simply ignore
  	 * the problem.  When the process attempts to write to the register backing store
  	 * for the first time, it will get a SEGFAULT in this case.
  	 */
  	vma = kmem_cache_zalloc(vm_area_cachep, GFP_KERNEL);
  	if (vma) {
  		INIT_LIST_HEAD(&vma->anon_vma_chain);
  		vma->vm_mm = current->mm;
  		vma->vm_start = current->thread.rbs_bot & PAGE_MASK;
  		vma->vm_end = vma->vm_start + PAGE_SIZE;
  		vma->vm_flags = VM_DATA_DEFAULT_FLAGS|VM_GROWSUP|VM_ACCOUNT;
  		vma->vm_page_prot = vm_get_page_prot(vma->vm_flags);
  		down_write(&current->mm->mmap_sem);
  		if (insert_vm_struct(current->mm, vma)) {
  			up_write(&current->mm->mmap_sem);
  			kmem_cache_free(vm_area_cachep, vma);
  			return;
  		}
  		up_write(&current->mm->mmap_sem);
  	}
  
  	/* map NaT-page at address zero to speed up speculative dereferencing of NULL: */
  	if (!(current->personality & MMAP_PAGE_ZERO)) {
  		vma = kmem_cache_zalloc(vm_area_cachep, GFP_KERNEL);
  		if (vma) {
  			INIT_LIST_HEAD(&vma->anon_vma_chain);
  			vma->vm_mm = current->mm;
  			vma->vm_end = PAGE_SIZE;
  			vma->vm_page_prot = __pgprot(pgprot_val(PAGE_READONLY) | _PAGE_MA_NAT);
  			vma->vm_flags = VM_READ | VM_MAYREAD | VM_IO |
  					VM_DONTEXPAND | VM_DONTDUMP;
  			down_write(&current->mm->mmap_sem);
  			if (insert_vm_struct(current->mm, vma)) {
  				up_write(&current->mm->mmap_sem);
  				kmem_cache_free(vm_area_cachep, vma);
  				return;
  			}
  			up_write(&current->mm->mmap_sem);
  		}
  	}
  }
  
  void
  free_initmem (void)
  {
  	free_reserved_area((unsigned long)ia64_imva(__init_begin),
  			   (unsigned long)ia64_imva(__init_end),
  			   0, "unused kernel");
  }
  
  void __init
  free_initrd_mem (unsigned long start, unsigned long end)
  {
  	/*
  	 * EFI uses 4KB pages while the kernel can use 4KB or bigger.
  	 * Thus EFI and the kernel may have different page sizes. It is
  	 * therefore possible to have the initrd share the same page as
  	 * the end of the kernel (given current setup).
  	 *
  	 * To avoid freeing/using the wrong page (kernel sized) we:
  	 *	- align up the beginning of initrd
  	 *	- align down the end of initrd
  	 *
  	 *  |             |
  	 *  |=============| a000
  	 *  |             |
  	 *  |             |
  	 *  |             | 9000
  	 *  |/////////////|
  	 *  |/////////////|
  	 *  |=============| 8000
  	 *  |///INITRD////|
  	 *  |/////////////|
  	 *  |/////////////| 7000
  	 *  |             |
  	 *  |KKKKKKKKKKKKK|
  	 *  |=============| 6000
  	 *  |KKKKKKKKKKKKK|
  	 *  |KKKKKKKKKKKKK|
  	 *  K=kernel using 8KB pages
  	 *
  	 * In this example, we must free page 8000 ONLY. So we must align up
  	 * initrd_start and keep initrd_end as is.
  	 */
  	start = PAGE_ALIGN(start);
  	end = end & PAGE_MASK;
  
  	if (start < end)
  		printk(KERN_INFO "Freeing initrd memory: %ldkB freed\n", (end - start) >> 10);
  
  	for (; start < end; start += PAGE_SIZE) {
  		if (!virt_addr_valid(start))
  			continue;
  		free_reserved_page(virt_to_page(start));
  	}
  }
  
  /*
   * This installs a clean page in the kernel's page table.
   */
  static struct page * __init
  put_kernel_page (struct page *page, unsigned long address, pgprot_t pgprot)
  {
  	pgd_t *pgd;
  	pud_t *pud;
  	pmd_t *pmd;
  	pte_t *pte;
  
  	if (!PageReserved(page))
  		printk(KERN_ERR "put_kernel_page: page at 0x%p not in reserved memory\n",
  		       page_address(page));
  
  	pgd = pgd_offset_k(address);		/* note: this is NOT pgd_offset()! */
  
  	{
  		pud = pud_alloc(&init_mm, pgd, address);
  		if (!pud)
  			goto out;
  		pmd = pmd_alloc(&init_mm, pud, address);
  		if (!pmd)
  			goto out;
  		pte = pte_alloc_kernel(pmd, address);
  		if (!pte)
  			goto out;
  		if (!pte_none(*pte))
  			goto out;
  		set_pte(pte, mk_pte(page, pgprot));
  	}
    out:
  	/* no need for flush_tlb */
  	return page;
  }
  
  static void __init
  setup_gate (void)
  {
  	void *gate_section;
  	struct page *page;
  
  	/*
  	 * Map the gate page twice: once read-only to export the ELF
  	 * headers etc. and once execute-only page to enable
  	 * privilege-promotion via "epc":
  	 */
  	gate_section = paravirt_get_gate_section();
  	page = virt_to_page(ia64_imva(gate_section));
  	put_kernel_page(page, GATE_ADDR, PAGE_READONLY);
  #ifdef HAVE_BUGGY_SEGREL
  	page = virt_to_page(ia64_imva(gate_section + PAGE_SIZE));
  	put_kernel_page(page, GATE_ADDR + PAGE_SIZE, PAGE_GATE);
  #else
  	put_kernel_page(page, GATE_ADDR + PERCPU_PAGE_SIZE, PAGE_GATE);
  	/* Fill in the holes (if any) with read-only zero pages: */
  	{
  		unsigned long addr;
  
  		for (addr = GATE_ADDR + PAGE_SIZE;
  		     addr < GATE_ADDR + PERCPU_PAGE_SIZE;
  		     addr += PAGE_SIZE)
  		{
  			put_kernel_page(ZERO_PAGE(0), addr,
  					PAGE_READONLY);
  			put_kernel_page(ZERO_PAGE(0), addr + PERCPU_PAGE_SIZE,
  					PAGE_READONLY);
  		}
  	}
  #endif
  	ia64_patch_gate();
  }
  
  void ia64_mmu_init(void *my_cpu_data)
  {
  	unsigned long pta, impl_va_bits;
  	extern void tlb_init(void);
  
  #ifdef CONFIG_DISABLE_VHPT
  #	define VHPT_ENABLE_BIT	0
  #else
  #	define VHPT_ENABLE_BIT	1
  #endif
  
  	/*
  	 * Check if the virtually mapped linear page table (VMLPT) overlaps with a mapped
  	 * address space.  The IA-64 architecture guarantees that at least 50 bits of
  	 * virtual address space are implemented but if we pick a large enough page size
  	 * (e.g., 64KB), the mapped address space is big enough that it will overlap with
  	 * VMLPT.  I assume that once we run on machines big enough to warrant 64KB pages,
  	 * IMPL_VA_MSB will be significantly bigger, so this is unlikely to become a
  	 * problem in practice.  Alternatively, we could truncate the top of the mapped
  	 * address space to not permit mappings that would overlap with the VMLPT.
  	 * --davidm 00/12/06
  	 */
  #	define pte_bits			3
  #	define mapped_space_bits	(3*(PAGE_SHIFT - pte_bits) + PAGE_SHIFT)
  	/*
  	 * The virtual page table has to cover the entire implemented address space within
  	 * a region even though not all of this space may be mappable.  The reason for
  	 * this is that the Access bit and Dirty bit fault handlers perform
  	 * non-speculative accesses to the virtual page table, so the address range of the
  	 * virtual page table itself needs to be covered by virtual page table.
  	 */
  #	define vmlpt_bits		(impl_va_bits - PAGE_SHIFT + pte_bits)
  #	define POW2(n)			(1ULL << (n))
  
  	impl_va_bits = ffz(~(local_cpu_data->unimpl_va_mask | (7UL << 61)));
  
  	if (impl_va_bits < 51 || impl_va_bits > 61)
  		panic("CPU has bogus IMPL_VA_MSB value of %lu!\n", impl_va_bits - 1);
  	/*
  	 * mapped_space_bits - PAGE_SHIFT is the total number of ptes we need,
  	 * which must fit into "vmlpt_bits - pte_bits" slots. Second half of
  	 * the test makes sure that our mapped space doesn't overlap the
  	 * unimplemented hole in the middle of the region.
  	 */
  	if ((mapped_space_bits - PAGE_SHIFT > vmlpt_bits - pte_bits) ||
  	    (mapped_space_bits > impl_va_bits - 1))
  		panic("Cannot build a big enough virtual-linear page table"
  		      " to cover mapped address space.\n"
  		      " Try using a smaller page size.\n");
  
  
  	/* place the VMLPT at the end of each page-table mapped region: */
  	pta = POW2(61) - POW2(vmlpt_bits);
  
  	/*
  	 * Set the (virtually mapped linear) page table address.  Bit
  	 * 8 selects between the short and long format, bits 2-7 the
  	 * size of the table, and bit 0 whether the VHPT walker is
  	 * enabled.
  	 */
  	ia64_set_pta(pta | (0 << 8) | (vmlpt_bits << 2) | VHPT_ENABLE_BIT);
  
  	ia64_tlb_init();
  
  #ifdef	CONFIG_HUGETLB_PAGE
  	ia64_set_rr(HPAGE_REGION_BASE, HPAGE_SHIFT << 2);
  	ia64_srlz_d();
  #endif
  }
  
  #ifdef CONFIG_VIRTUAL_MEM_MAP
  int vmemmap_find_next_valid_pfn(int node, int i)
  {
  	unsigned long end_address, hole_next_pfn;
  	unsigned long stop_address;
  	pg_data_t *pgdat = NODE_DATA(node);
  
  	end_address = (unsigned long) &vmem_map[pgdat->node_start_pfn + i];
  	end_address = PAGE_ALIGN(end_address);
  
  	stop_address = (unsigned long) &vmem_map[
  		pgdat->node_start_pfn + pgdat->node_spanned_pages];
  
  	do {
  		pgd_t *pgd;
  		pud_t *pud;
  		pmd_t *pmd;
  		pte_t *pte;
  
  		pgd = pgd_offset_k(end_address);
  		if (pgd_none(*pgd)) {
  			end_address += PGDIR_SIZE;
  			continue;
  		}
  
  		pud = pud_offset(pgd, end_address);
  		if (pud_none(*pud)) {
  			end_address += PUD_SIZE;
  			continue;
  		}
  
  		pmd = pmd_offset(pud, end_address);
  		if (pmd_none(*pmd)) {
  			end_address += PMD_SIZE;
  			continue;
  		}
  
  		pte = pte_offset_kernel(pmd, end_address);
  retry_pte:
  		if (pte_none(*pte)) {
  			end_address += PAGE_SIZE;
  			pte++;
  			if ((end_address < stop_address) &&
  			    (end_address != ALIGN(end_address, 1UL << PMD_SHIFT)))
  				goto retry_pte;
  			continue;
  		}
  		/* Found next valid vmem_map page */
  		break;
  	} while (end_address < stop_address);
  
  	end_address = min(end_address, stop_address);
  	end_address = end_address - (unsigned long) vmem_map + sizeof(struct page) - 1;
  	hole_next_pfn = end_address / sizeof(struct page);
  	return hole_next_pfn - pgdat->node_start_pfn;
  }
  
  int __init create_mem_map_page_table(u64 start, u64 end, void *arg)
  {
  	unsigned long address, start_page, end_page;
  	struct page *map_start, *map_end;
  	int node;
  	pgd_t *pgd;
  	pud_t *pud;
  	pmd_t *pmd;
  	pte_t *pte;
  
  	map_start = vmem_map + (__pa(start) >> PAGE_SHIFT);
  	map_end   = vmem_map + (__pa(end) >> PAGE_SHIFT);
  
  	start_page = (unsigned long) map_start & PAGE_MASK;
  	end_page = PAGE_ALIGN((unsigned long) map_end);
  	node = paddr_to_nid(__pa(start));
  
  	for (address = start_page; address < end_page; address += PAGE_SIZE) {
  		pgd = pgd_offset_k(address);
  		if (pgd_none(*pgd))
  			pgd_populate(&init_mm, pgd, alloc_bootmem_pages_node(NODE_DATA(node), PAGE_SIZE));
  		pud = pud_offset(pgd, address);
  
  		if (pud_none(*pud))
  			pud_populate(&init_mm, pud, alloc_bootmem_pages_node(NODE_DATA(node), PAGE_SIZE));
  		pmd = pmd_offset(pud, address);
  
  		if (pmd_none(*pmd))
  			pmd_populate_kernel(&init_mm, pmd, alloc_bootmem_pages_node(NODE_DATA(node), PAGE_SIZE));
  		pte = pte_offset_kernel(pmd, address);
  
  		if (pte_none(*pte))
  			set_pte(pte, pfn_pte(__pa(alloc_bootmem_pages_node(NODE_DATA(node), PAGE_SIZE)) >> PAGE_SHIFT,
  					     PAGE_KERNEL));
  	}
  	return 0;
  }
  
  struct memmap_init_callback_data {
  	struct page *start;
  	struct page *end;
  	int nid;
  	unsigned long zone;
  };
  
  static int __meminit
  virtual_memmap_init(u64 start, u64 end, void *arg)
  {
  	struct memmap_init_callback_data *args;
  	struct page *map_start, *map_end;
  
  	args = (struct memmap_init_callback_data *) arg;
  	map_start = vmem_map + (__pa(start) >> PAGE_SHIFT);
  	map_end   = vmem_map + (__pa(end) >> PAGE_SHIFT);
  
  	if (map_start < args->start)
  		map_start = args->start;
  	if (map_end > args->end)
  		map_end = args->end;
  
  	/*
  	 * We have to initialize "out of bounds" struct page elements that fit completely
  	 * on the same pages that were allocated for the "in bounds" elements because they
  	 * may be referenced later (and found to be "reserved").
  	 */
  	map_start -= ((unsigned long) map_start & (PAGE_SIZE - 1)) / sizeof(struct page);
  	map_end += ((PAGE_ALIGN((unsigned long) map_end) - (unsigned long) map_end)
  		    / sizeof(struct page));
  
  	if (map_start < map_end)
  		memmap_init_zone((unsigned long)(map_end - map_start),
  				 args->nid, args->zone, page_to_pfn(map_start),
  				 MEMMAP_EARLY);
  	return 0;
  }
  
  void __meminit
  memmap_init (unsigned long size, int nid, unsigned long zone,
  	     unsigned long start_pfn)
  {
  	if (!vmem_map)
  		memmap_init_zone(size, nid, zone, start_pfn, MEMMAP_EARLY);
  	else {
  		struct page *start;
  		struct memmap_init_callback_data args;
  
  		start = pfn_to_page(start_pfn);
  		args.start = start;
  		args.end = start + size;
  		args.nid = nid;
  		args.zone = zone;
  
  		efi_memmap_walk(virtual_memmap_init, &args);
  	}
  }
  
  int
  ia64_pfn_valid (unsigned long pfn)
  {
  	char byte;
  	struct page *pg = pfn_to_page(pfn);
  
  	return     (__get_user(byte, (char __user *) pg) == 0)
  		&& ((((u64)pg & PAGE_MASK) == (((u64)(pg + 1) - 1) & PAGE_MASK))
  			|| (__get_user(byte, (char __user *) (pg + 1) - 1) == 0));
  }
  EXPORT_SYMBOL(ia64_pfn_valid);
  
  int __init find_largest_hole(u64 start, u64 end, void *arg)
  {
  	u64 *max_gap = arg;
  
  	static u64 last_end = PAGE_OFFSET;
  
  	/* NOTE: this algorithm assumes efi memmap table is ordered */
  
  	if (*max_gap < (start - last_end))
  		*max_gap = start - last_end;
  	last_end = end;
  	return 0;
  }
  
  #endif /* CONFIG_VIRTUAL_MEM_MAP */
  
  int __init register_active_ranges(u64 start, u64 len, int nid)
  {
  	u64 end = start + len;
  
  #ifdef CONFIG_KEXEC
  	if (start > crashk_res.start && start < crashk_res.end)
  		start = crashk_res.end;
  	if (end > crashk_res.start && end < crashk_res.end)
  		end = crashk_res.start;
  #endif
  
  	if (start < end)
  		memblock_add_node(__pa(start), end - start, nid);
  	return 0;
  }
  
  static int __init
  count_reserved_pages(u64 start, u64 end, void *arg)
  {
  	unsigned long num_reserved = 0;
  	unsigned long *count = arg;
  
  	for (; start < end; start += PAGE_SIZE)
  		if (PageReserved(virt_to_page(start)))
  			++num_reserved;
  	*count += num_reserved;
  	return 0;
  }
  
  int
  find_max_min_low_pfn (u64 start, u64 end, void *arg)
  {
  	unsigned long pfn_start, pfn_end;
  #ifdef CONFIG_FLATMEM
  	pfn_start = (PAGE_ALIGN(__pa(start))) >> PAGE_SHIFT;
  	pfn_end = (PAGE_ALIGN(__pa(end - 1))) >> PAGE_SHIFT;
  #else
  	pfn_start = GRANULEROUNDDOWN(__pa(start)) >> PAGE_SHIFT;
  	pfn_end = GRANULEROUNDUP(__pa(end - 1)) >> PAGE_SHIFT;
  #endif
  	min_low_pfn = min(min_low_pfn, pfn_start);
  	max_low_pfn = max(max_low_pfn, pfn_end);
  	return 0;
  }
  
  /*
   * Boot command-line option "nolwsys" can be used to disable the use of any light-weight
   * system call handler.  When this option is in effect, all fsyscalls will end up bubbling
   * down into the kernel and calling the normal (heavy-weight) syscall handler.  This is
   * useful for performance testing, but conceivably could also come in handy for debugging
   * purposes.
   */
  
  static int nolwsys __initdata;
  
  static int __init
  nolwsys_setup (char *s)
  {
  	nolwsys = 1;
  	return 1;
  }
  
  __setup("nolwsys", nolwsys_setup);
  
  void __init
  mem_init (void)
  {
  	long reserved_pages, codesize, datasize, initsize;
  	pg_data_t *pgdat;
  	int i;
  
  	BUG_ON(PTRS_PER_PGD * sizeof(pgd_t) != PAGE_SIZE);
  	BUG_ON(PTRS_PER_PMD * sizeof(pmd_t) != PAGE_SIZE);
  	BUG_ON(PTRS_PER_PTE * sizeof(pte_t) != PAGE_SIZE);
  
  #ifdef CONFIG_PCI
  	/*
  	 * This needs to be called _after_ the command line has been parsed but _before_
  	 * any drivers that may need the PCI DMA interface are initialized or bootmem has
  	 * been freed.
  	 */
  	platform_dma_init();
  #endif
  
  #ifdef CONFIG_FLATMEM
  	BUG_ON(!mem_map);
  	max_mapnr = max_low_pfn;
  #endif
  
  	high_memory = __va(max_low_pfn * PAGE_SIZE);
  
  	for_each_online_pgdat(pgdat)
  		if (pgdat->bdata->node_bootmem_map)
  			totalram_pages += free_all_bootmem_node(pgdat);
  
  	reserved_pages = 0;
  	efi_memmap_walk(count_reserved_pages, &reserved_pages);
  
  	codesize =  (unsigned long) _etext - (unsigned long) _stext;
  	datasize =  (unsigned long) _edata - (unsigned long) _etext;
  	initsize =  (unsigned long) __init_end - (unsigned long) __init_begin;
  
  	printk(KERN_INFO "Memory: %luk/%luk available (%luk code, %luk reserved, "
  	       "%luk data, %luk init)\n", nr_free_pages() << (PAGE_SHIFT - 10),
  	       num_physpages << (PAGE_SHIFT - 10), codesize >> 10,
  	       reserved_pages << (PAGE_SHIFT - 10), datasize >> 10, initsize >> 10);
  
  
  	/*
  	 * For fsyscall entrpoints with no light-weight handler, use the ordinary
  	 * (heavy-weight) handler, but mark it by setting bit 0, so the fsyscall entry
  	 * code can tell them apart.
  	 */
  	for (i = 0; i < NR_syscalls; ++i) {
  		extern unsigned long sys_call_table[NR_syscalls];
  		unsigned long *fsyscall_table = paravirt_get_fsyscall_table();
  
  		if (!fsyscall_table[i] || nolwsys)
  			fsyscall_table[i] = sys_call_table[i] | 1;
  	}
  	setup_gate();
  }
  
  #ifdef CONFIG_MEMORY_HOTPLUG
  int arch_add_memory(int nid, u64 start, u64 size)
  {
  	pg_data_t *pgdat;
  	struct zone *zone;
  	unsigned long start_pfn = start >> PAGE_SHIFT;
  	unsigned long nr_pages = size >> PAGE_SHIFT;
  	int ret;
  
  	pgdat = NODE_DATA(nid);
  
  	zone = pgdat->node_zones + ZONE_NORMAL;
  	ret = __add_pages(nid, zone, start_pfn, nr_pages);
  
  	if (ret)
  		printk("%s: Problem encountered in __add_pages() as ret=%d\n",
  		       __func__,  ret);
  
  	return ret;
  }
  
  #ifdef CONFIG_MEMORY_HOTREMOVE
  int arch_remove_memory(u64 start, u64 size)
  {
  	unsigned long start_pfn = start >> PAGE_SHIFT;
  	unsigned long nr_pages = size >> PAGE_SHIFT;
  	struct zone *zone;
  	int ret;
  
  	zone = page_zone(pfn_to_page(start_pfn));
  	ret = __remove_pages(zone, start_pfn, nr_pages);
  	if (ret)
  		pr_warn("%s: Problem encountered in __remove_pages() as"
  			" ret=%d\n", __func__,  ret);
  
  	return ret;
  }
  #endif
  #endif
  
  /*
   * Even when CONFIG_IA32_SUPPORT is not enabled it is
   * useful to have the Linux/x86 domain registered to
   * avoid an attempted module load when emulators call
   * personality(PER_LINUX32). This saves several milliseconds
   * on each such call.
   */
  static struct exec_domain ia32_exec_domain;
  
  static int __init
  per_linux32_init(void)
  {
  	ia32_exec_domain.name = "Linux/x86";
  	ia32_exec_domain.handler = NULL;
  	ia32_exec_domain.pers_low = PER_LINUX32;
  	ia32_exec_domain.pers_high = PER_LINUX32;
  	ia32_exec_domain.signal_map = default_exec_domain.signal_map;
  	ia32_exec_domain.signal_invmap = default_exec_domain.signal_invmap;
  	register_exec_domain(&ia32_exec_domain);
  
  	return 0;
  }
  
  __initcall(per_linux32_init);
  