arch/powerpc/mm/pgtable_64.c - third_party/linux - Git at Google

 /*
  *  This file contains ioremap and related functions for 64-bit machines.
  *
  *  Derived from arch/ppc64/mm/init.c
  *    Copyright (C) 1995-1996 Gary Thomas (gdt@linuxppc.org)
  *
  *  Modifications by Paul Mackerras (PowerMac) (paulus@samba.org)
  *  and Cort Dougan (PReP) (cort@cs.nmt.edu)
  *    Copyright (C) 1996 Paul Mackerras
  *
  *  Derived from "arch/i386/mm/init.c"
  *    Copyright (C) 1991, 1992, 1993, 1994  Linus Torvalds
  *
  *  Dave Engebretsen <engebret@us.ibm.com>
  *      Rework for PPC64 port.
  *
  *  This program is free software; you can redistribute it and/or
  *  modify it under the terms of the GNU General Public License
  *  as published by the Free Software Foundation; either version
  *  2 of the License, or (at your option) any later version.
  *
  */

 #include <linux/signal.h>
 #include <linux/sched.h>
 #include <linux/kernel.h>
 #include <linux/errno.h>
 #include <linux/string.h>
 #include <linux/export.h>
 #include <linux/types.h>
 #include <linux/mman.h>
 #include <linux/mm.h>
 #include <linux/swap.h>
 #include <linux/stddef.h>
 #include <linux/vmalloc.h>
 #include <linux/memblock.h>
 #include <linux/slab.h>
 #include <linux/hugetlb.h>

 #include <asm/pgalloc.h>
 #include <asm/page.h>
 #include <asm/prom.h>
 #include <asm/io.h>
 #include <asm/mmu_context.h>
 #include <asm/pgtable.h>
 #include <asm/mmu.h>
 #include <asm/smp.h>
 #include <asm/machdep.h>
 #include <asm/tlb.h>
 #include <asm/processor.h>
 #include <asm/cputable.h>
 #include <asm/sections.h>
 #include <asm/firmware.h>
 #include <asm/dma.h>

 #include "mmu_decl.h"

 #ifdef CONFIG_PPC_STD_MMU_64
 #if TASK_SIZE_USER64 > (1UL << (ESID_BITS + SID_SHIFT))
 #error TASK_SIZE_USER64 exceeds user VSID range
 #endif
 #endif

 #ifdef CONFIG_PPC_BOOK3S_64
 /*
  * partition table and process table for ISA 3.0
  */
 struct prtb_entry *process_tb;
 struct patb_entry *partition_tb;
 /*
  * page table size
  */
 unsigned long __pte_index_size;
 EXPORT_SYMBOL(__pte_index_size);
 unsigned long __pmd_index_size;
 EXPORT_SYMBOL(__pmd_index_size);
 unsigned long __pud_index_size;
 EXPORT_SYMBOL(__pud_index_size);
 unsigned long __pgd_index_size;
 EXPORT_SYMBOL(__pgd_index_size);
 unsigned long __pmd_cache_index;
 EXPORT_SYMBOL(__pmd_cache_index);
 unsigned long __pte_table_size;
 EXPORT_SYMBOL(__pte_table_size);
 unsigned long __pmd_table_size;
 EXPORT_SYMBOL(__pmd_table_size);
 unsigned long __pud_table_size;
 EXPORT_SYMBOL(__pud_table_size);
 unsigned long __pgd_table_size;
 EXPORT_SYMBOL(__pgd_table_size);
 unsigned long __pmd_val_bits;
 EXPORT_SYMBOL(__pmd_val_bits);
 unsigned long __pud_val_bits;
 EXPORT_SYMBOL(__pud_val_bits);
 unsigned long __pgd_val_bits;
 EXPORT_SYMBOL(__pgd_val_bits);
 unsigned long __kernel_virt_start;
 EXPORT_SYMBOL(__kernel_virt_start);
 unsigned long __kernel_virt_size;
 EXPORT_SYMBOL(__kernel_virt_size);
 unsigned long __vmalloc_start;
 EXPORT_SYMBOL(__vmalloc_start);
 unsigned long __vmalloc_end;
 EXPORT_SYMBOL(__vmalloc_end);
 struct page *vmemmap;
 EXPORT_SYMBOL(vmemmap);
 unsigned long __pte_frag_nr;
 EXPORT_SYMBOL(__pte_frag_nr);
 unsigned long __pte_frag_size_shift;
 EXPORT_SYMBOL(__pte_frag_size_shift);
 unsigned long ioremap_bot;
 #else /* !CONFIG_PPC_BOOK3S_64 */
 unsigned long ioremap_bot = IOREMAP_BASE;
 #endif

 /**
  * __ioremap_at - Low level function to establish the page tables
  *                for an IO mapping
  */
 void __iomem * __ioremap_at(phys_addr_t pa, void *ea, unsigned long size,
 			    unsigned long flags)
 {
 	unsigned long i;

 	/* Make sure we have the base flags */
 	if ((flags & _PAGE_PRESENT) == 0)
 		flags |= pgprot_val(PAGE_KERNEL);

 	/* We don't support the 4K PFN hack with ioremap */
 	if (flags & H_PAGE_4K_PFN)
 		return NULL;

 	WARN_ON(pa & ~PAGE_MASK);
 	WARN_ON(((unsigned long)ea) & ~PAGE_MASK);
 	WARN_ON(size & ~PAGE_MASK);

 	for (i = 0; i < size; i += PAGE_SIZE)
 		if (map_kernel_page((unsigned long)ea+i, pa+i, flags))
 			return NULL;

 	return (void __iomem *)ea;
 }

 /**
  * __iounmap_from - Low level function to tear down the page tables
  *                  for an IO mapping. This is used for mappings that
  *                  are manipulated manually, like partial unmapping of
  *                  PCI IOs or ISA space.
  */
 void __iounmap_at(void *ea, unsigned long size)
 {
 	WARN_ON(((unsigned long)ea) & ~PAGE_MASK);
 	WARN_ON(size & ~PAGE_MASK);

 	unmap_kernel_range((unsigned long)ea, size);
 }

 void __iomem * __ioremap_caller(phys_addr_t addr, unsigned long size,
 				unsigned long flags, void *caller)
 {
 	phys_addr_t paligned;
 	void __iomem *ret;

 	/*
 	 * Choose an address to map it to.
 	 * Once the imalloc system is running, we use it.
 	 * Before that, we map using addresses going
 	 * up from ioremap_bot.  imalloc will use
 	 * the addresses from ioremap_bot through
 	 * IMALLOC_END
 	 *
 	 */
 	paligned = addr & PAGE_MASK;
 	size = PAGE_ALIGN(addr + size) - paligned;

 	if ((size == 0) || (paligned == 0))
 		return NULL;

 	if (slab_is_available()) {
 		struct vm_struct *area;

 		area = __get_vm_area_caller(size, VM_IOREMAP,
 					    ioremap_bot, IOREMAP_END,
 					    caller);
 		if (area == NULL)
 			return NULL;

 		area->phys_addr = paligned;
 		ret = __ioremap_at(paligned, area->addr, size, flags);
 		if (!ret)
 			vunmap(area->addr);
 	} else {
 		ret = __ioremap_at(paligned, (void *)ioremap_bot, size, flags);
 		if (ret)
 			ioremap_bot += size;
 	}

 	if (ret)
 		ret += addr & ~PAGE_MASK;
 	return ret;
 }

 void __iomem * __ioremap(phys_addr_t addr, unsigned long size,
 			 unsigned long flags)
 {
 	return __ioremap_caller(addr, size, flags, __builtin_return_address(0));
 }

 void __iomem * ioremap(phys_addr_t addr, unsigned long size)
 {
 	unsigned long flags = pgprot_val(pgprot_noncached(__pgprot(0)));
 	void *caller = __builtin_return_address(0);

 	if (ppc_md.ioremap)
 		return ppc_md.ioremap(addr, size, flags, caller);
 	return __ioremap_caller(addr, size, flags, caller);
 }

 void __iomem * ioremap_wc(phys_addr_t addr, unsigned long size)
 {
 	unsigned long flags = pgprot_val(pgprot_noncached_wc(__pgprot(0)));
 	void *caller = __builtin_return_address(0);

 	if (ppc_md.ioremap)
 		return ppc_md.ioremap(addr, size, flags, caller);
 	return __ioremap_caller(addr, size, flags, caller);
 }

 void __iomem * ioremap_prot(phys_addr_t addr, unsigned long size,
 			     unsigned long flags)
 {
 	void *caller = __builtin_return_address(0);

 	/* writeable implies dirty for kernel addresses */
 	if (flags & _PAGE_WRITE)
 		flags |= _PAGE_DIRTY;

 	/* we don't want to let _PAGE_EXEC leak out */
 	flags &= ~_PAGE_EXEC;
 	/*
 	 * Force kernel mapping.
 	 */
 #if defined(CONFIG_PPC_BOOK3S_64)
 	flags |= _PAGE_PRIVILEGED;
 #else
 	flags &= ~_PAGE_USER;
 #endif


 #ifdef _PAGE_BAP_SR
 	/* _PAGE_USER contains _PAGE_BAP_SR on BookE using the new PTE format
 	 * which means that we just cleared supervisor access... oops ;-) This
 	 * restores it
 	 */
 	flags |= _PAGE_BAP_SR;
 #endif

 	if (ppc_md.ioremap)
 		return ppc_md.ioremap(addr, size, flags, caller);
 	return __ioremap_caller(addr, size, flags, caller);
 }


 /*
  * Unmap an IO region and remove it from imalloc'd list.
  * Access to IO memory should be serialized by driver.
  */
 void __iounmap(volatile void __iomem *token)
 {
 	void *addr;

 	if (!slab_is_available())
 		return;

 	addr = (void *) ((unsigned long __force)
 			 PCI_FIX_ADDR(token) & PAGE_MASK);
 	if ((unsigned long)addr < ioremap_bot) {
 		printk(KERN_WARNING "Attempt to iounmap early bolted mapping"
 		       " at 0x%p\n", addr);
 		return;
 	}
 	vunmap(addr);
 }

 void iounmap(volatile void __iomem *token)
 {
 	if (ppc_md.iounmap)
 		ppc_md.iounmap(token);
 	else
 		__iounmap(token);
 }

 EXPORT_SYMBOL(ioremap);
 EXPORT_SYMBOL(ioremap_wc);
 EXPORT_SYMBOL(ioremap_prot);
 EXPORT_SYMBOL(__ioremap);
 EXPORT_SYMBOL(__ioremap_at);
 EXPORT_SYMBOL(iounmap);
 EXPORT_SYMBOL(__iounmap);
 EXPORT_SYMBOL(__iounmap_at);

 #ifndef __PAGETABLE_PUD_FOLDED
 /* 4 level page table */
 struct page *pgd_page(pgd_t pgd)
 {
 	if (pgd_huge(pgd))
 		return pte_page(pgd_pte(pgd));
 	return virt_to_page(pgd_page_vaddr(pgd));
 }
 #endif

 struct page *pud_page(pud_t pud)
 {
 	if (pud_huge(pud))
 		return pte_page(pud_pte(pud));
 	return virt_to_page(pud_page_vaddr(pud));
 }

 /*
  * For hugepage we have pfn in the pmd, we use PTE_RPN_SHIFT bits for flags
  * For PTE page, we have a PTE_FRAG_SIZE (4K) aligned virtual address.
  */
 struct page *pmd_page(pmd_t pmd)
 {
 	if (pmd_trans_huge(pmd) || pmd_huge(pmd))
 		return pte_page(pmd_pte(pmd));
 	return virt_to_page(pmd_page_vaddr(pmd));
 }

 #ifdef CONFIG_PPC_64K_PAGES
 static pte_t *get_from_cache(struct mm_struct *mm)
 {
 	void *pte_frag, *ret;

 	spin_lock(&mm->page_table_lock);
 	ret = mm->context.pte_frag;
 	if (ret) {
 		pte_frag = ret + PTE_FRAG_SIZE;
 		/*
 		 * If we have taken up all the fragments mark PTE page NULL
 		 */
 		if (((unsigned long)pte_frag & ~PAGE_MASK) == 0)
 			pte_frag = NULL;
 		mm->context.pte_frag = pte_frag;
 	}
 	spin_unlock(&mm->page_table_lock);
 	return (pte_t *)ret;
 }

 static pte_t *__alloc_for_cache(struct mm_struct *mm, int kernel)
 {
 	void *ret = NULL;
 	struct page *page = alloc_page(GFP_KERNEL | __GFP_NOTRACK | __GFP_ZERO);
 	if (!page)
 		return NULL;
 	if (!kernel && !pgtable_page_ctor(page)) {
 		__free_page(page);
 		return NULL;
 	}

 	ret = page_address(page);
 	spin_lock(&mm->page_table_lock);
 	/*
 	 * If we find pgtable_page set, we return
 	 * the allocated page with single fragement
 	 * count.
 	 */
 	if (likely(!mm->context.pte_frag)) {
 		set_page_count(page, PTE_FRAG_NR);
 		mm->context.pte_frag = ret + PTE_FRAG_SIZE;
 	}
 	spin_unlock(&mm->page_table_lock);

 	return (pte_t *)ret;
 }

 pte_t *pte_fragment_alloc(struct mm_struct *mm, unsigned long vmaddr, int kernel)
 {
 	pte_t *pte;

 	pte = get_from_cache(mm);
 	if (pte)
 		return pte;

 	return __alloc_for_cache(mm, kernel);
 }
 #endif /* CONFIG_PPC_64K_PAGES */

 void pte_fragment_free(unsigned long *table, int kernel)
 {
 	struct page *page = virt_to_page(table);
 	if (put_page_testzero(page)) {
 		if (!kernel)
 			pgtable_page_dtor(page);
 		free_hot_cold_page(page, 0);
 	}
 }

 #ifdef CONFIG_SMP
 void pgtable_free_tlb(struct mmu_gather *tlb, void *table, int shift)
 {
 	unsigned long pgf = (unsigned long)table;

 	BUG_ON(shift > MAX_PGTABLE_INDEX_SIZE);
 	pgf |= shift;
 	tlb_remove_table(tlb, (void *)pgf);
 }

 void __tlb_remove_table(void *_table)
 {
 	void *table = (void *)((unsigned long)_table & ~MAX_PGTABLE_INDEX_SIZE);
 	unsigned shift = (unsigned long)_table & MAX_PGTABLE_INDEX_SIZE;

 	if (!shift)
 		/* PTE page needs special handling */
 		pte_fragment_free(table, 0);
 	else {
 		BUG_ON(shift > MAX_PGTABLE_INDEX_SIZE);
 		kmem_cache_free(PGT_CACHE(shift), table);
 	}
 }
 #else
 void pgtable_free_tlb(struct mmu_gather *tlb, void *table, int shift)
 {
 	if (!shift) {
 		/* PTE page needs special handling */
 		pte_fragment_free(table, 0);
 	} else {
 		BUG_ON(shift > MAX_PGTABLE_INDEX_SIZE);
 		kmem_cache_free(PGT_CACHE(shift), table);
 	}
 }
 #endif
	/*
	* This file contains ioremap and related functions for 64-bit machines.
	*
	* Derived from arch/ppc64/mm/init.c
	* Copyright (C) 1995-1996 Gary Thomas (gdt@linuxppc.org)
	*
	* Modifications by Paul Mackerras (PowerMac) (paulus@samba.org)
	* and Cort Dougan (PReP) (cort@cs.nmt.edu)
	* Copyright (C) 1996 Paul Mackerras
	*
	* Derived from "arch/i386/mm/init.c"
	* Copyright (C) 1991, 1992, 1993, 1994 Linus Torvalds
	*
	* Dave Engebretsen <engebret@us.ibm.com>
	* Rework for PPC64 port.
	*
	* This program is free software; you can redistribute it and/or
	* modify it under the terms of the GNU General Public License
	* as published by the Free Software Foundation; either version
	* 2 of the License, or (at your option) any later version.
	*
	*/

	#include <linux/signal.h>
	#include <linux/sched.h>
	#include <linux/kernel.h>
	#include <linux/errno.h>
	#include <linux/string.h>
	#include <linux/export.h>
	#include <linux/types.h>
	#include <linux/mman.h>
	#include <linux/mm.h>
	#include <linux/swap.h>
	#include <linux/stddef.h>
	#include <linux/vmalloc.h>
	#include <linux/memblock.h>
	#include <linux/slab.h>
	#include <linux/hugetlb.h>

	#include <asm/pgalloc.h>
	#include <asm/page.h>
	#include <asm/prom.h>
	#include <asm/io.h>
	#include <asm/mmu_context.h>
	#include <asm/pgtable.h>
	#include <asm/mmu.h>
	#include <asm/smp.h>
	#include <asm/machdep.h>
	#include <asm/tlb.h>
	#include <asm/processor.h>
	#include <asm/cputable.h>
	#include <asm/sections.h>
	#include <asm/firmware.h>
	#include <asm/dma.h>

	#include "mmu_decl.h"

	#ifdef CONFIG_PPC_STD_MMU_64
	#if TASK_SIZE_USER64 > (1UL << (ESID_BITS + SID_SHIFT))
	#error TASK_SIZE_USER64 exceeds user VSID range
	#endif
	#endif

	#ifdef CONFIG_PPC_BOOK3S_64
	/*
	* partition table and process table for ISA 3.0
	*/
	struct prtb_entry *process_tb;
	struct patb_entry *partition_tb;
	/*
	* page table size
	*/
	unsigned long __pte_index_size;
	EXPORT_SYMBOL(__pte_index_size);
	unsigned long __pmd_index_size;
	EXPORT_SYMBOL(__pmd_index_size);
	unsigned long __pud_index_size;
	EXPORT_SYMBOL(__pud_index_size);
	unsigned long __pgd_index_size;
	EXPORT_SYMBOL(__pgd_index_size);
	unsigned long __pmd_cache_index;
	EXPORT_SYMBOL(__pmd_cache_index);
	unsigned long __pte_table_size;
	EXPORT_SYMBOL(__pte_table_size);
	unsigned long __pmd_table_size;
	EXPORT_SYMBOL(__pmd_table_size);
	unsigned long __pud_table_size;
	EXPORT_SYMBOL(__pud_table_size);
	unsigned long __pgd_table_size;
	EXPORT_SYMBOL(__pgd_table_size);
	unsigned long __pmd_val_bits;
	EXPORT_SYMBOL(__pmd_val_bits);
	unsigned long __pud_val_bits;
	EXPORT_SYMBOL(__pud_val_bits);
	unsigned long __pgd_val_bits;
	EXPORT_SYMBOL(__pgd_val_bits);
	unsigned long __kernel_virt_start;
	EXPORT_SYMBOL(__kernel_virt_start);
	unsigned long __kernel_virt_size;
	EXPORT_SYMBOL(__kernel_virt_size);
	unsigned long __vmalloc_start;
	EXPORT_SYMBOL(__vmalloc_start);
	unsigned long __vmalloc_end;
	EXPORT_SYMBOL(__vmalloc_end);
	struct page *vmemmap;
	EXPORT_SYMBOL(vmemmap);
	unsigned long __pte_frag_nr;
	EXPORT_SYMBOL(__pte_frag_nr);
	unsigned long __pte_frag_size_shift;
	EXPORT_SYMBOL(__pte_frag_size_shift);
	unsigned long ioremap_bot;
	#else /* !CONFIG_PPC_BOOK3S_64 */
	unsigned long ioremap_bot = IOREMAP_BASE;
	#endif

	/**
	* __ioremap_at - Low level function to establish the page tables
	* for an IO mapping
	*/
	void __iomem * __ioremap_at(phys_addr_t pa, void *ea, unsigned long size,
	unsigned long flags)
	{
	unsigned long i;

	/* Make sure we have the base flags */
	if ((flags & _PAGE_PRESENT) == 0)
	flags \|= pgprot_val(PAGE_KERNEL);

	/* We don't support the 4K PFN hack with ioremap */
	if (flags & H_PAGE_4K_PFN)
	return NULL;

	WARN_ON(pa & ~PAGE_MASK);
	WARN_ON(((unsigned long)ea) & ~PAGE_MASK);
	WARN_ON(size & ~PAGE_MASK);

	for (i = 0; i < size; i += PAGE_SIZE)
	if (map_kernel_page((unsigned long)ea+i, pa+i, flags))
	return NULL;

	return (void __iomem *)ea;
	}

	/**
	* __iounmap_from - Low level function to tear down the page tables
	* for an IO mapping. This is used for mappings that
	* are manipulated manually, like partial unmapping of
	* PCI IOs or ISA space.
	*/
	void __iounmap_at(void *ea, unsigned long size)
	{
	WARN_ON(((unsigned long)ea) & ~PAGE_MASK);
	WARN_ON(size & ~PAGE_MASK);

	unmap_kernel_range((unsigned long)ea, size);
	}

	void __iomem * __ioremap_caller(phys_addr_t addr, unsigned long size,
	unsigned long flags, void *caller)
	{
	phys_addr_t paligned;
	void __iomem *ret;

	/*
	* Choose an address to map it to.
	* Once the imalloc system is running, we use it.
	* Before that, we map using addresses going
	* up from ioremap_bot. imalloc will use
	* the addresses from ioremap_bot through
	* IMALLOC_END
	*
	*/
	paligned = addr & PAGE_MASK;
	size = PAGE_ALIGN(addr + size) - paligned;

	if ((size == 0) \|\| (paligned == 0))
	return NULL;

	if (slab_is_available()) {
	struct vm_struct *area;

	area = __get_vm_area_caller(size, VM_IOREMAP,
	ioremap_bot, IOREMAP_END,
	caller);
	if (area == NULL)
	return NULL;

	area->phys_addr = paligned;
	ret = __ioremap_at(paligned, area->addr, size, flags);
	if (!ret)
	vunmap(area->addr);
	} else {
	ret = __ioremap_at(paligned, (void *)ioremap_bot, size, flags);
	if (ret)
	ioremap_bot += size;
	}

	if (ret)
	ret += addr & ~PAGE_MASK;
	return ret;
	}

	void __iomem * __ioremap(phys_addr_t addr, unsigned long size,
	unsigned long flags)
	{
	return __ioremap_caller(addr, size, flags, __builtin_return_address(0));
	}

	void __iomem * ioremap(phys_addr_t addr, unsigned long size)
	{
	unsigned long flags = pgprot_val(pgprot_noncached(__pgprot(0)));
	void *caller = __builtin_return_address(0);

	if (ppc_md.ioremap)
	return ppc_md.ioremap(addr, size, flags, caller);
	return __ioremap_caller(addr, size, flags, caller);
	}

	void __iomem * ioremap_wc(phys_addr_t addr, unsigned long size)
	{
	unsigned long flags = pgprot_val(pgprot_noncached_wc(__pgprot(0)));
	void *caller = __builtin_return_address(0);

	if (ppc_md.ioremap)
	return ppc_md.ioremap(addr, size, flags, caller);
	return __ioremap_caller(addr, size, flags, caller);
	}

	void __iomem * ioremap_prot(phys_addr_t addr, unsigned long size,
	unsigned long flags)
	{
	void *caller = __builtin_return_address(0);

	/* writeable implies dirty for kernel addresses */
	if (flags & _PAGE_WRITE)
	flags \|= _PAGE_DIRTY;

	/* we don't want to let _PAGE_EXEC leak out */
	flags &= ~_PAGE_EXEC;
	/*
	* Force kernel mapping.
	*/
	#if defined(CONFIG_PPC_BOOK3S_64)
	flags \|= _PAGE_PRIVILEGED;
	#else
	flags &= ~_PAGE_USER;
	#endif


	#ifdef _PAGE_BAP_SR
	/* _PAGE_USER contains _PAGE_BAP_SR on BookE using the new PTE format
	* which means that we just cleared supervisor access... oops ;-) This
	* restores it
	*/
	flags \|= _PAGE_BAP_SR;
	#endif

	if (ppc_md.ioremap)
	return ppc_md.ioremap(addr, size, flags, caller);
	return __ioremap_caller(addr, size, flags, caller);
	}


	/*
	* Unmap an IO region and remove it from imalloc'd list.
	* Access to IO memory should be serialized by driver.
	*/
	void __iounmap(volatile void __iomem *token)
	{
	void *addr;

	if (!slab_is_available())
	return;

	addr = (void *) ((unsigned long __force)
	PCI_FIX_ADDR(token) & PAGE_MASK);
	if ((unsigned long)addr < ioremap_bot) {
	printk(KERN_WARNING "Attempt to iounmap early bolted mapping"
	" at 0x%p\n", addr);
	return;
	}
	vunmap(addr);
	}

	void iounmap(volatile void __iomem *token)
	{
	if (ppc_md.iounmap)
	ppc_md.iounmap(token);
	else
	__iounmap(token);
	}

	EXPORT_SYMBOL(ioremap);
	EXPORT_SYMBOL(ioremap_wc);
	EXPORT_SYMBOL(ioremap_prot);
	EXPORT_SYMBOL(__ioremap);
	EXPORT_SYMBOL(__ioremap_at);
	EXPORT_SYMBOL(iounmap);
	EXPORT_SYMBOL(__iounmap);
	EXPORT_SYMBOL(__iounmap_at);

	#ifndef __PAGETABLE_PUD_FOLDED
	/* 4 level page table */
	struct page *pgd_page(pgd_t pgd)
	{
	if (pgd_huge(pgd))
	return pte_page(pgd_pte(pgd));
	return virt_to_page(pgd_page_vaddr(pgd));
	}
	#endif

	struct page *pud_page(pud_t pud)
	{
	if (pud_huge(pud))
	return pte_page(pud_pte(pud));
	return virt_to_page(pud_page_vaddr(pud));
	}

	/*
	* For hugepage we have pfn in the pmd, we use PTE_RPN_SHIFT bits for flags
	* For PTE page, we have a PTE_FRAG_SIZE (4K) aligned virtual address.
	*/
	struct page *pmd_page(pmd_t pmd)
	{
	if (pmd_trans_huge(pmd) \|\| pmd_huge(pmd))
	return pte_page(pmd_pte(pmd));
	return virt_to_page(pmd_page_vaddr(pmd));
	}

	#ifdef CONFIG_PPC_64K_PAGES
	static pte_t get_from_cache(struct mm_struct mm)
	{
	void pte_frag, ret;

	spin_lock(&mm->page_table_lock);
	ret = mm->context.pte_frag;
	if (ret) {
	pte_frag = ret + PTE_FRAG_SIZE;
	/*
	* If we have taken up all the fragments mark PTE page NULL
	*/
	if (((unsigned long)pte_frag & ~PAGE_MASK) == 0)
	pte_frag = NULL;
	mm->context.pte_frag = pte_frag;
	}
	spin_unlock(&mm->page_table_lock);
	return (pte_t *)ret;
	}

	static pte_t __alloc_for_cache(struct mm_struct mm, int kernel)
	{
	void *ret = NULL;
	struct page *page = alloc_page(GFP_KERNEL \| __GFP_NOTRACK \| __GFP_ZERO);
	if (!page)
	return NULL;
	if (!kernel && !pgtable_page_ctor(page)) {
	__free_page(page);
	return NULL;
	}

	ret = page_address(page);
	spin_lock(&mm->page_table_lock);
	/*
	* If we find pgtable_page set, we return
	* the allocated page with single fragement
	* count.
	*/
	if (likely(!mm->context.pte_frag)) {
	set_page_count(page, PTE_FRAG_NR);
	mm->context.pte_frag = ret + PTE_FRAG_SIZE;
	}
	spin_unlock(&mm->page_table_lock);

	return (pte_t *)ret;
	}

	pte_t pte_fragment_alloc(struct mm_struct mm, unsigned long vmaddr, int kernel)
	{
	pte_t *pte;

	pte = get_from_cache(mm);
	if (pte)
	return pte;

	return __alloc_for_cache(mm, kernel);
	}
	#endif /* CONFIG_PPC_64K_PAGES */

	void pte_fragment_free(unsigned long *table, int kernel)
	{
	struct page *page = virt_to_page(table);
	if (put_page_testzero(page)) {
	if (!kernel)
	pgtable_page_dtor(page);
	free_hot_cold_page(page, 0);
	}
	}

	#ifdef CONFIG_SMP
	void pgtable_free_tlb(struct mmu_gather tlb, void table, int shift)
	{
	unsigned long pgf = (unsigned long)table;

	BUG_ON(shift > MAX_PGTABLE_INDEX_SIZE);
	pgf \|= shift;
	tlb_remove_table(tlb, (void *)pgf);
	}

	void __tlb_remove_table(void *_table)
	{
	void table = (void )((unsigned long)_table & ~MAX_PGTABLE_INDEX_SIZE);
	unsigned shift = (unsigned long)_table & MAX_PGTABLE_INDEX_SIZE;

	if (!shift)
	/* PTE page needs special handling */
	pte_fragment_free(table, 0);
	else {
	BUG_ON(shift > MAX_PGTABLE_INDEX_SIZE);
	kmem_cache_free(PGT_CACHE(shift), table);
	}
	}
	#else
	void pgtable_free_tlb(struct mmu_gather tlb, void table, int shift)
	{
	if (!shift) {
	/* PTE page needs special handling */
	pte_fragment_free(table, 0);
	} else {
	BUG_ON(shift > MAX_PGTABLE_INDEX_SIZE);
	kmem_cache_free(PGT_CACHE(shift), table);
	}
	}
	#endif