arch/ia64/mm/init.c - kernel/msm-4.9 - Gitiles

 /*
  * Initialize MMU support.
  *
  * Copyright (C) 1998-2003 Hewlett-Packard Co
  *	David Mosberger-Tang <davidm@hpl.hp.com>
  */
 #include <linux/config.h>
 #include <linux/kernel.h>
 #include <linux/init.h>

 #include <linux/bootmem.h>
 #include <linux/efi.h>
 #include <linux/elf.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 <asm/a.out.h>
 #include <asm/dma.h>
 #include <asm/ia32.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/system.h>
 #include <asm/tlb.h>
 #include <asm/uaccess.h>
 #include <asm/unistd.h>
 #include <asm/mca.h>

 DEFINE_PER_CPU(struct mmu_gather, mmu_gathers);

 DEFINE_PER_CPU(unsigned long *, __pgtable_quicklist);
 DEFINE_PER_CPU(long, __pgtable_quicklist_size);

 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);

 #define MIN_PGT_PAGES			25UL
 #define MAX_PGT_FREES_PER_PASS		16L
 #define PGT_FRACTION_OF_NODE_MEM	16

 static inline long
 max_pgt_pages(void)
 {
 	u64 node_free_pages, max_pgt_pages;

 #ifndef	CONFIG_NUMA
 	node_free_pages = nr_free_pages();
 #else
 	node_free_pages = nr_free_pages_pgdat(NODE_DATA(numa_node_id()));
 #endif
 	max_pgt_pages = node_free_pages / PGT_FRACTION_OF_NODE_MEM;
 	max_pgt_pages = max(max_pgt_pages, MIN_PGT_PAGES);
 	return max_pgt_pages;
 }

 static inline long
 min_pages_to_free(void)
 {
 	long pages_to_free;

 	pages_to_free = pgtable_quicklist_size - max_pgt_pages();
 	pages_to_free = min(pages_to_free, MAX_PGT_FREES_PER_PASS);
 	return pages_to_free;
 }

 void
 check_pgt_cache(void)
 {
 	long pages_to_free;

 	if (unlikely(pgtable_quicklist_size <= MIN_PGT_PAGES))
 		return;

 	preempt_disable();
 	while (unlikely((pages_to_free = min_pages_to_free()) > 0)) {
 		while (pages_to_free--) {
 			free_page((unsigned long)pgtable_quicklist_alloc());
 		}
 		preempt_enable();
 		preempt_disable();
 	}
 	preempt_enable();
 }

 void
 lazy_mmu_prot_update (pte_t pte)
 {
 	unsigned long addr;
 	struct page *page;

 	if (!pte_exec(pte))
 		return;				/* not an executable 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);
 	set_bit(PG_arch_1, &page->flags);	/* mark page as clean */
 }

 inline void
 ia64_set_rbs_bot (void)
 {
 	unsigned long stack_size = current->signal->rlim[RLIMIT_STACK].rlim_max & -16;

 	if (stack_size > MAX_USER_STACK_SIZE)
 		stack_size = MAX_USER_STACK_SIZE;
 	current->thread.rbs_bot = STACK_TOP - 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_alloc(vm_area_cachep, SLAB_KERNEL);
 	if (vma) {
 		memset(vma, 0, sizeof(*vma));
 		vma->vm_mm = current->mm;
 		vma->vm_start = current->thread.rbs_bot & PAGE_MASK;
 		vma->vm_end = vma->vm_start + PAGE_SIZE;
 		vma->vm_page_prot = protection_map[VM_DATA_DEFAULT_FLAGS & 0x7];
 		vma->vm_flags = VM_DATA_DEFAULT_FLAGS | VM_GROWSUP;
 		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_alloc(vm_area_cachep, SLAB_KERNEL);
 		if (vma) {
 			memset(vma, 0, sizeof(*vma));
 			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_RESERVED;
 			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)
 {
 	unsigned long addr, eaddr;

 	addr = (unsigned long) ia64_imva(__init_begin);
 	eaddr = (unsigned long) ia64_imva(__init_end);
 	while (addr < eaddr) {
 		ClearPageReserved(virt_to_page(addr));
 		set_page_count(virt_to_page(addr), 1);
 		free_page(addr);
 		++totalram_pages;
 		addr += PAGE_SIZE;
 	}
 	printk(KERN_INFO "Freeing unused kernel memory: %ldkB freed\n",
 	       (__init_end - __init_begin) >> 10);
 }

 void
 free_initrd_mem (unsigned long start, unsigned long end)
 {
 	struct page *page;
 	/*
 	 * 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;
 		page = virt_to_page(start);
 		ClearPageReserved(page);
 		set_page_count(page, 1);
 		free_page(start);
 		++totalram_pages;
 	}
 }

 /*
  * This installs a clean page in the kernel's page table.
  */
 struct page *
 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()! */

 	spin_lock(&init_mm.page_table_lock);
 	{
 		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_map(&init_mm, pmd, address);
 		if (!pte)
 			goto out;
 		if (!pte_none(*pte)) {
 			pte_unmap(pte);
 			goto out;
 		}
 		set_pte(pte, mk_pte(page, pgprot));
 		pte_unmap(pte);
 	}
   out:	spin_unlock(&init_mm.page_table_lock);
 	/* no need for flush_tlb */
 	return page;
 }

 static void
 setup_gate (void)
 {
 	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":
 	 */
 	page = virt_to_page(ia64_imva(__start_gate_section));
 	put_kernel_page(page, GATE_ADDR, PAGE_READONLY);
 #ifdef HAVE_BUGGY_SEGREL
 	page = virt_to_page(ia64_imva(__start_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);
 #endif
 	ia64_patch_gate();
 }

 void __devinit
 ia64_mmu_init (void *my_cpu_data)
 {
 	unsigned long psr, pta, impl_va_bits;
 	extern void __devinit tlb_init (void);

 #ifdef CONFIG_DISABLE_VHPT
 #	define VHPT_ENABLE_BIT	0
 #else
 #	define VHPT_ENABLE_BIT	1
 #endif

 	/* Pin mapping for percpu area into TLB */
 	psr = ia64_clear_ic();
 	ia64_itr(0x2, IA64_TR_PERCPU_DATA, PERCPU_ADDR,
 		 pte_val(pfn_pte(__pa(my_cpu_data) >> PAGE_SHIFT, PAGE_KERNEL)),
 		 PERCPU_PAGE_SHIFT);

 	ia64_set_psr(psr);
 	ia64_srlz_i();

 	/*
 	 * 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);

 	/* place the VMLPT at the end of each page-table mapped region: */
 	pta = POW2(61) - POW2(vmlpt_bits);

 	if (POW2(mapped_space_bits) >= pta)
 		panic("mm/init: overlap between virtually mapped linear page table and "
 		      "mapped kernel space!");
 	/*
 	 * 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
 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
 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));
 	return 0;
 }

 void
 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);
 	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
 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 */

 static int
 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;
 }

 /*
  * 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;

 static int __init
 nolwsys_setup (char *s)
 {
 	nolwsys = 1;
 	return 1;
 }

 __setup("nolwsys", nolwsys_setup);

 void
 mem_init (void)
 {
 	long reserved_pages, codesize, datasize, initsize;
 	pg_data_t *pgdat;
 	int i;
 	static struct kcore_list kcore_mem, kcore_vmem, kcore_kernel;

 	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

 #ifndef CONFIG_DISCONTIGMEM
 	if (!mem_map)
 		BUG();
 	max_mapnr = max_low_pfn;
 #endif

 	high_memory = __va(max_low_pfn * PAGE_SIZE);

 	kclist_add(&kcore_mem, __va(0), max_low_pfn * PAGE_SIZE);
 	kclist_add(&kcore_vmem, (void *)VMALLOC_START, VMALLOC_END-VMALLOC_START);
 	kclist_add(&kcore_kernel, _stext, _end - _stext);

 	for_each_pgdat(pgdat)
 		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", (unsigned long) 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 fsyscall_table[NR_syscalls];
 		extern unsigned long sys_call_table[NR_syscalls];

 		if (!fsyscall_table[i] || nolwsys)
 			fsyscall_table[i] = sys_call_table[i] | 1;
 	}
 	setup_gate();

 #ifdef CONFIG_IA32_SUPPORT
 	ia32_mem_init();
 #endif
 }
	/*
	* Initialize MMU support.
	*
	* Copyright (C) 1998-2003 Hewlett-Packard Co
	* David Mosberger-Tang <davidm@hpl.hp.com>
	*/
	#include <linux/config.h>
	#include <linux/kernel.h>
	#include <linux/init.h>

	#include <linux/bootmem.h>
	#include <linux/efi.h>
	#include <linux/elf.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 <asm/a.out.h>
	#include <asm/dma.h>
	#include <asm/ia32.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/system.h>
	#include <asm/tlb.h>
	#include <asm/uaccess.h>
	#include <asm/unistd.h>
	#include <asm/mca.h>

	DEFINE_PER_CPU(struct mmu_gather, mmu_gathers);

	DEFINE_PER_CPU(unsigned long *, __pgtable_quicklist);
	DEFINE_PER_CPU(long, __pgtable_quicklist_size);

	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);

	#define MIN_PGT_PAGES 25UL
	#define MAX_PGT_FREES_PER_PASS 16L
	#define PGT_FRACTION_OF_NODE_MEM 16

	static inline long
	max_pgt_pages(void)
	{
	u64 node_free_pages, max_pgt_pages;

	#ifndef CONFIG_NUMA
	node_free_pages = nr_free_pages();
	#else
	node_free_pages = nr_free_pages_pgdat(NODE_DATA(numa_node_id()));
	#endif
	max_pgt_pages = node_free_pages / PGT_FRACTION_OF_NODE_MEM;
	max_pgt_pages = max(max_pgt_pages, MIN_PGT_PAGES);
	return max_pgt_pages;
	}

	static inline long
	min_pages_to_free(void)
	{
	long pages_to_free;

	pages_to_free = pgtable_quicklist_size - max_pgt_pages();
	pages_to_free = min(pages_to_free, MAX_PGT_FREES_PER_PASS);
	return pages_to_free;
	}

	void
	check_pgt_cache(void)
	{
	long pages_to_free;

	if (unlikely(pgtable_quicklist_size <= MIN_PGT_PAGES))
	return;

	preempt_disable();
	while (unlikely((pages_to_free = min_pages_to_free()) > 0)) {
	while (pages_to_free--) {
	free_page((unsigned long)pgtable_quicklist_alloc());
	}
	preempt_enable();
	preempt_disable();
	}
	preempt_enable();
	}

	void
	lazy_mmu_prot_update (pte_t pte)
	{
	unsigned long addr;
	struct page *page;

	if (!pte_exec(pte))
	return; /* not an executable 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);
	set_bit(PG_arch_1, &page->flags); /* mark page as clean */
	}

	inline void
	ia64_set_rbs_bot (void)
	{
	unsigned long stack_size = current->signal->rlim[RLIMIT_STACK].rlim_max & -16;

	if (stack_size > MAX_USER_STACK_SIZE)
	stack_size = MAX_USER_STACK_SIZE;
	current->thread.rbs_bot = STACK_TOP - 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_alloc(vm_area_cachep, SLAB_KERNEL);
	if (vma) {
	memset(vma, 0, sizeof(*vma));
	vma->vm_mm = current->mm;
	vma->vm_start = current->thread.rbs_bot & PAGE_MASK;
	vma->vm_end = vma->vm_start + PAGE_SIZE;
	vma->vm_page_prot = protection_map[VM_DATA_DEFAULT_FLAGS & 0x7];
	vma->vm_flags = VM_DATA_DEFAULT_FLAGS \| VM_GROWSUP;
	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_alloc(vm_area_cachep, SLAB_KERNEL);
	if (vma) {
	memset(vma, 0, sizeof(*vma));
	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_RESERVED;
	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)
	{
	unsigned long addr, eaddr;

	addr = (unsigned long) ia64_imva(__init_begin);
	eaddr = (unsigned long) ia64_imva(__init_end);
	while (addr < eaddr) {
	ClearPageReserved(virt_to_page(addr));
	set_page_count(virt_to_page(addr), 1);
	free_page(addr);
	++totalram_pages;
	addr += PAGE_SIZE;
	}
	printk(KERN_INFO "Freeing unused kernel memory: %ldkB freed\n",
	(__init_end - __init_begin) >> 10);
	}

	void
	free_initrd_mem (unsigned long start, unsigned long end)
	{
	struct page *page;
	/*
	* 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;
	page = virt_to_page(start);
	ClearPageReserved(page);
	set_page_count(page, 1);
	free_page(start);
	++totalram_pages;
	}
	}

	/*
	* This installs a clean page in the kernel's page table.
	*/
	struct page *
	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()! */

	spin_lock(&init_mm.page_table_lock);
	{
	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_map(&init_mm, pmd, address);
	if (!pte)
	goto out;
	if (!pte_none(*pte)) {
	pte_unmap(pte);
	goto out;
	}
	set_pte(pte, mk_pte(page, pgprot));
	pte_unmap(pte);
	}
	out: spin_unlock(&init_mm.page_table_lock);
	/* no need for flush_tlb */
	return page;
	}

	static void
	setup_gate (void)
	{
	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":
	*/
	page = virt_to_page(ia64_imva(__start_gate_section));
	put_kernel_page(page, GATE_ADDR, PAGE_READONLY);
	#ifdef HAVE_BUGGY_SEGREL
	page = virt_to_page(ia64_imva(__start_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);
	#endif
	ia64_patch_gate();
	}

	void __devinit
	ia64_mmu_init (void *my_cpu_data)
	{
	unsigned long psr, pta, impl_va_bits;
	extern void __devinit tlb_init (void);

	#ifdef CONFIG_DISABLE_VHPT
	# define VHPT_ENABLE_BIT 0
	#else
	# define VHPT_ENABLE_BIT 1
	#endif

	/* Pin mapping for percpu area into TLB */
	psr = ia64_clear_ic();
	ia64_itr(0x2, IA64_TR_PERCPU_DATA, PERCPU_ADDR,
	pte_val(pfn_pte(__pa(my_cpu_data) >> PAGE_SHIFT, PAGE_KERNEL)),
	PERCPU_PAGE_SHIFT);

	ia64_set_psr(psr);
	ia64_srlz_i();

	/*
	* 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);

	/* place the VMLPT at the end of each page-table mapped region: */
	pta = POW2(61) - POW2(vmlpt_bits);

	if (POW2(mapped_space_bits) >= pta)
	panic("mm/init: overlap between virtually mapped linear page table and "
	"mapped kernel space!");
	/*
	* 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
	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
	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));
	return 0;
	}

	void
	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);
	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
	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 */

	static int
	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;
	}

	/*
	* 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;

	static int __init
	nolwsys_setup (char *s)
	{
	nolwsys = 1;
	return 1;
	}

	__setup("nolwsys", nolwsys_setup);

	void
	mem_init (void)
	{
	long reserved_pages, codesize, datasize, initsize;
	pg_data_t *pgdat;
	int i;
	static struct kcore_list kcore_mem, kcore_vmem, kcore_kernel;

	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

	#ifndef CONFIG_DISCONTIGMEM
	if (!mem_map)
	BUG();
	max_mapnr = max_low_pfn;
	#endif

	high_memory = __va(max_low_pfn * PAGE_SIZE);

	kclist_add(&kcore_mem, __va(0), max_low_pfn * PAGE_SIZE);
	kclist_add(&kcore_vmem, (void *)VMALLOC_START, VMALLOC_END-VMALLOC_START);
	kclist_add(&kcore_kernel, _stext, _end - _stext);

	for_each_pgdat(pgdat)
	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", (unsigned long) 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 fsyscall_table[NR_syscalls];
	extern unsigned long sys_call_table[NR_syscalls];

	if (!fsyscall_table[i] \|\| nolwsys)
	fsyscall_table[i] = sys_call_table[i] \| 1;
	}
	setup_gate();

	#ifdef CONFIG_IA32_SUPPORT
	ia32_mem_init();
	#endif
	}