arch/powerpc/include/asm/page.h - linux - Git at Google

 /* SPDX-License-Identifier: GPL-2.0-or-later */
 #ifndef _ASM_POWERPC_PAGE_H
 #define _ASM_POWERPC_PAGE_H

 /*
  * Copyright (C) 2001,2005 IBM Corporation.
  */

 #ifndef __ASSEMBLY__
 #include <linux/types.h>
 #include <linux/kernel.h>
 #else
 #include <asm/types.h>
 #endif
 #include <asm/asm-const.h>

 /*
  * On regular PPC32 page size is 4K (but we support 4K/16K/64K/256K pages
  * on PPC44x and 4K/16K on 8xx). For PPC64 we support either 4K or 64K software
  * page size. When using 64K pages however, whether we are really supporting
  * 64K pages in HW or not is irrelevant to those definitions.
  */
 #define PAGE_SHIFT		CONFIG_PPC_PAGE_SHIFT
 #define PAGE_SIZE		(ASM_CONST(1) << PAGE_SHIFT)

 #ifndef __ASSEMBLY__
 #ifndef CONFIG_HUGETLB_PAGE
 #define HPAGE_SHIFT PAGE_SHIFT
 #elif defined(CONFIG_PPC_BOOK3S_64)
 extern unsigned int hpage_shift;
 #define HPAGE_SHIFT hpage_shift
 #elif defined(CONFIG_PPC_8xx)
 #define HPAGE_SHIFT		19	/* 512k pages */
 #elif defined(CONFIG_PPC_E500)
 #define HPAGE_SHIFT		22	/* 4M pages */
 #endif
 #define HPAGE_SIZE		((1UL) << HPAGE_SHIFT)
 #define HPAGE_MASK		(~(HPAGE_SIZE - 1))
 #define HUGETLB_PAGE_ORDER	(HPAGE_SHIFT - PAGE_SHIFT)
 #define HUGE_MAX_HSTATE		(MMU_PAGE_COUNT-1)
 #endif

 /*
  * Subtle: (1 << PAGE_SHIFT) is an int, not an unsigned long. So if we
  * assign PAGE_MASK to a larger type it gets extended the way we want
  * (i.e. with 1s in the high bits)
  */
 #define PAGE_MASK      (~((1 << PAGE_SHIFT) - 1))

 /*
  * KERNELBASE is the virtual address of the start of the kernel, it's often
  * the same as PAGE_OFFSET, but _might not be_.
  *
  * The kdump dump kernel is one example where KERNELBASE != PAGE_OFFSET.
  *
  * PAGE_OFFSET is the virtual address of the start of lowmem.
  *
  * PHYSICAL_START is the physical address of the start of the kernel.
  *
  * MEMORY_START is the physical address of the start of lowmem.
  *
  * KERNELBASE, PAGE_OFFSET, and PHYSICAL_START are all configurable on
  * ppc32 and based on how they are set we determine MEMORY_START.
  *
  * For the linear mapping the following equation should be true:
  * KERNELBASE - PAGE_OFFSET = PHYSICAL_START - MEMORY_START
  *
  * Also, KERNELBASE >= PAGE_OFFSET and PHYSICAL_START >= MEMORY_START
  *
  * There are two ways to determine a physical address from a virtual one:
  * va = pa + PAGE_OFFSET - MEMORY_START
  * va = pa + KERNELBASE - PHYSICAL_START
  *
  * If you want to know something's offset from the start of the kernel you
  * should subtract KERNELBASE.
  *
  * If you want to test if something's a kernel address, use is_kernel_addr().
  */

 #define KERNELBASE      ASM_CONST(CONFIG_KERNEL_START)
 #define PAGE_OFFSET	ASM_CONST(CONFIG_PAGE_OFFSET)
 #define LOAD_OFFSET	ASM_CONST((CONFIG_KERNEL_START-CONFIG_PHYSICAL_START))

 #if defined(CONFIG_NONSTATIC_KERNEL)
 #ifndef __ASSEMBLY__

 extern phys_addr_t memstart_addr;
 extern phys_addr_t kernstart_addr;

 #if defined(CONFIG_RELOCATABLE) && defined(CONFIG_PPC32)
 extern long long virt_phys_offset;
 #endif

 #endif /* __ASSEMBLY__ */
 #define PHYSICAL_START	kernstart_addr

 #else	/* !CONFIG_NONSTATIC_KERNEL */
 #define PHYSICAL_START	ASM_CONST(CONFIG_PHYSICAL_START)
 #endif

 /* See Description below for VIRT_PHYS_OFFSET */
 #if defined(CONFIG_PPC32) && defined(CONFIG_BOOKE)
 #ifdef CONFIG_RELOCATABLE
 #define VIRT_PHYS_OFFSET virt_phys_offset
 #else
 #define VIRT_PHYS_OFFSET (KERNELBASE - PHYSICAL_START)
 #endif
 #endif

 #ifdef CONFIG_PPC64
 #define MEMORY_START	0UL
 #elif defined(CONFIG_NONSTATIC_KERNEL)
 #define MEMORY_START	memstart_addr
 #else
 #define MEMORY_START	(PHYSICAL_START + PAGE_OFFSET - KERNELBASE)
 #endif

 #ifdef CONFIG_FLATMEM
 #define ARCH_PFN_OFFSET		((unsigned long)(MEMORY_START >> PAGE_SHIFT))
 #endif

 #define virt_to_pfn(kaddr)	(__pa(kaddr) >> PAGE_SHIFT)
 #define virt_to_page(kaddr)	pfn_to_page(virt_to_pfn(kaddr))
 #define pfn_to_kaddr(pfn)	__va((pfn) << PAGE_SHIFT)

 #define virt_addr_valid(vaddr)	({					\
 	unsigned long _addr = (unsigned long)vaddr;			\
 	_addr >= PAGE_OFFSET && _addr < (unsigned long)high_memory &&	\
 	pfn_valid(virt_to_pfn(_addr));					\
 })

 /*
  * On Book-E parts we need __va to parse the device tree and we can't
  * determine MEMORY_START until then.  However we can determine PHYSICAL_START
  * from information at hand (program counter, TLB lookup).
  *
  * On BookE with RELOCATABLE && PPC32
  *
  *   With RELOCATABLE && PPC32,  we support loading the kernel at any physical
  *   address without any restriction on the page alignment.
  *
  *   We find the runtime address of _stext and relocate ourselves based on
  *   the following calculation:
  *
  *  	  virtual_base = ALIGN_DOWN(KERNELBASE,256M) +
  *  				MODULO(_stext.run,256M)
  *   and create the following mapping:
  *
  * 	  ALIGN_DOWN(_stext.run,256M) => ALIGN_DOWN(KERNELBASE,256M)
  *
  *   When we process relocations, we cannot depend on the
  *   existing equation for the __va()/__pa() translations:
  *
  * 	   __va(x) = (x)  - PHYSICAL_START + KERNELBASE
  *
  *   Where:
  *   	 PHYSICAL_START = kernstart_addr = Physical address of _stext
  *  	 KERNELBASE = Compiled virtual address of _stext.
  *
  *   This formula holds true iff, kernel load address is TLB page aligned.
  *
  *   In our case, we need to also account for the shift in the kernel Virtual
  *   address.
  *
  *   E.g.,
  *
  *   Let the kernel be loaded at 64MB and KERNELBASE be 0xc0000000 (same as PAGE_OFFSET).
  *   In this case, we would be mapping 0 to 0xc0000000, and kernstart_addr = 64M
  *
  *   Now __va(1MB) = (0x100000) - (0x4000000) + 0xc0000000
  *                 = 0xbc100000 , which is wrong.
  *
  *   Rather, it should be : 0xc0000000 + 0x100000 = 0xc0100000
  *      	according to our mapping.
  *
  *   Hence we use the following formula to get the translations right:
  *
  * 	  __va(x) = (x) - [ PHYSICAL_START - Effective KERNELBASE ]
  *
  * 	  Where :
  * 		PHYSICAL_START = dynamic load address.(kernstart_addr variable)
  * 		Effective KERNELBASE = virtual_base =
  * 				     = ALIGN_DOWN(KERNELBASE,256M) +
  * 						MODULO(PHYSICAL_START,256M)
  *
  * 	To make the cost of __va() / __pa() more light weight, we introduce
  * 	a new variable virt_phys_offset, which will hold :
  *
  * 	virt_phys_offset = Effective KERNELBASE - PHYSICAL_START
  * 			 = ALIGN_DOWN(KERNELBASE,256M) -
  * 			 	ALIGN_DOWN(PHYSICALSTART,256M)
  *
  * 	Hence :
  *
  * 	__va(x) = x - PHYSICAL_START + Effective KERNELBASE
  * 		= x + virt_phys_offset
  *
  * 		and
  * 	__pa(x) = x + PHYSICAL_START - Effective KERNELBASE
  * 		= x - virt_phys_offset
  *
  * On non-Book-E PPC64 PAGE_OFFSET and MEMORY_START are constants so use
  * the other definitions for __va & __pa.
  */
 #if defined(CONFIG_PPC32) && defined(CONFIG_BOOKE)
 #define __va(x) ((void *)(unsigned long)((phys_addr_t)(x) + VIRT_PHYS_OFFSET))
 #define __pa(x) ((phys_addr_t)(unsigned long)(x) - VIRT_PHYS_OFFSET)
 #else
 #ifdef CONFIG_PPC64

 #define VIRTUAL_WARN_ON(x)	WARN_ON(IS_ENABLED(CONFIG_DEBUG_VIRTUAL) && (x))

 /*
  * gcc miscompiles (unsigned long)(&static_var) - PAGE_OFFSET
  * with -mcmodel=medium, so we use & and | instead of - and + on 64-bit.
  * This also results in better code generation.
  */
 #define __va(x)								\
 ({									\
 	VIRTUAL_WARN_ON((unsigned long)(x) >= PAGE_OFFSET);		\
 	(void *)(unsigned long)((phys_addr_t)(x) | PAGE_OFFSET);	\
 })

 #define __pa(x)								\
 ({									\
 	VIRTUAL_WARN_ON((unsigned long)(x) < PAGE_OFFSET);		\
 	(unsigned long)(x) & 0x0fffffffffffffffUL;			\
 })

 #else /* 32-bit, non book E */
 #define __va(x) ((void *)(unsigned long)((phys_addr_t)(x) + PAGE_OFFSET - MEMORY_START))
 #define __pa(x) ((unsigned long)(x) - PAGE_OFFSET + MEMORY_START)
 #endif
 #endif

 /*
  * Unfortunately the PLT is in the BSS in the PPC32 ELF ABI,
  * and needs to be executable.  This means the whole heap ends
  * up being executable.
  */
 #define VM_DATA_DEFAULT_FLAGS32	VM_DATA_FLAGS_TSK_EXEC
 #define VM_DATA_DEFAULT_FLAGS64	VM_DATA_FLAGS_NON_EXEC

 #ifdef __powerpc64__
 #include <asm/page_64.h>
 #else
 #include <asm/page_32.h>
 #endif

 /*
  * Don't compare things with KERNELBASE or PAGE_OFFSET to test for
  * "kernelness", use is_kernel_addr() - it should do what you want.
  */
 #ifdef CONFIG_PPC_BOOK3E_64
 #define is_kernel_addr(x)	((x) >= 0x8000000000000000ul)
 #elif defined(CONFIG_PPC_BOOK3S_64)
 #define is_kernel_addr(x)	((x) >= PAGE_OFFSET)
 #else
 #define is_kernel_addr(x)	((x) >= TASK_SIZE)
 #endif

 #ifndef CONFIG_PPC_BOOK3S_64
 /*
  * Use the top bit of the higher-level page table entries to indicate whether
  * the entries we point to contain hugepages.  This works because we know that
  * the page tables live in kernel space.  If we ever decide to support having
  * page tables at arbitrary addresses, this breaks and will have to change.
  */
 #ifdef CONFIG_PPC64
 #define PD_HUGE 0x8000000000000000UL
 #else
 #define PD_HUGE 0x80000000
 #endif

 #else	/* CONFIG_PPC_BOOK3S_64 */
 /*
  * Book3S 64 stores real addresses in the hugepd entries to
  * avoid overlaps with _PAGE_PRESENT and _PAGE_PTE.
  */
 #define HUGEPD_ADDR_MASK	(0x0ffffffffffffffful & ~HUGEPD_SHIFT_MASK)
 #endif /* CONFIG_PPC_BOOK3S_64 */

 /*
  * Some number of bits at the level of the page table that points to
  * a hugepte are used to encode the size.  This masks those bits.
  * On 8xx, HW assistance requires 4k alignment for the hugepte.
  */
 #ifdef CONFIG_PPC_8xx
 #define HUGEPD_SHIFT_MASK     0xfff
 #else
 #define HUGEPD_SHIFT_MASK     0x3f
 #endif

 #ifndef __ASSEMBLY__

 #ifdef CONFIG_PPC_BOOK3S_64
 #include <asm/pgtable-be-types.h>
 #else
 #include <asm/pgtable-types.h>
 #endif

 struct page;
 extern void clear_user_page(void *page, unsigned long vaddr, struct page *pg);
 extern void copy_user_page(void *to, void *from, unsigned long vaddr,
 		struct page *p);
 extern int devmem_is_allowed(unsigned long pfn);

 #ifdef CONFIG_PPC_SMLPAR
 void arch_free_page(struct page *page, int order);
 #define HAVE_ARCH_FREE_PAGE
 #endif

 struct vm_area_struct;

 extern unsigned long kernstart_virt_addr;

 static inline unsigned long kaslr_offset(void)
 {
 	return kernstart_virt_addr - KERNELBASE;
 }

 #include <asm-generic/memory_model.h>
 #endif /* __ASSEMBLY__ */

 #endif /* _ASM_POWERPC_PAGE_H */
	/* SPDX-License-Identifier: GPL-2.0-or-later */
	#ifndef _ASM_POWERPC_PAGE_H
	#define _ASM_POWERPC_PAGE_H

	/*
	* Copyright (C) 2001,2005 IBM Corporation.
	*/

	#ifndef __ASSEMBLY__
	#include <linux/types.h>
	#include <linux/kernel.h>
	#else
	#include <asm/types.h>
	#endif
	#include <asm/asm-const.h>

	/*
	* On regular PPC32 page size is 4K (but we support 4K/16K/64K/256K pages
	* on PPC44x and 4K/16K on 8xx). For PPC64 we support either 4K or 64K software
	* page size. When using 64K pages however, whether we are really supporting
	* 64K pages in HW or not is irrelevant to those definitions.
	*/
	#define PAGE_SHIFT CONFIG_PPC_PAGE_SHIFT
	#define PAGE_SIZE (ASM_CONST(1) << PAGE_SHIFT)

	#ifndef __ASSEMBLY__
	#ifndef CONFIG_HUGETLB_PAGE
	#define HPAGE_SHIFT PAGE_SHIFT
	#elif defined(CONFIG_PPC_BOOK3S_64)
	extern unsigned int hpage_shift;
	#define HPAGE_SHIFT hpage_shift
	#elif defined(CONFIG_PPC_8xx)
	#define HPAGE_SHIFT 19 /* 512k pages */
	#elif defined(CONFIG_PPC_E500)
	#define HPAGE_SHIFT 22 /* 4M pages */
	#endif
	#define HPAGE_SIZE ((1UL) << HPAGE_SHIFT)
	#define HPAGE_MASK (~(HPAGE_SIZE - 1))
	#define HUGETLB_PAGE_ORDER (HPAGE_SHIFT - PAGE_SHIFT)
	#define HUGE_MAX_HSTATE (MMU_PAGE_COUNT-1)
	#endif

	/*
	* Subtle: (1 << PAGE_SHIFT) is an int, not an unsigned long. So if we
	* assign PAGE_MASK to a larger type it gets extended the way we want
	* (i.e. with 1s in the high bits)
	*/
	#define PAGE_MASK (~((1 << PAGE_SHIFT) - 1))

	/*
	* KERNELBASE is the virtual address of the start of the kernel, it's often
	* the same as PAGE_OFFSET, but _might not be_.
	*
	* The kdump dump kernel is one example where KERNELBASE != PAGE_OFFSET.
	*
	* PAGE_OFFSET is the virtual address of the start of lowmem.
	*
	* PHYSICAL_START is the physical address of the start of the kernel.
	*
	* MEMORY_START is the physical address of the start of lowmem.
	*
	* KERNELBASE, PAGE_OFFSET, and PHYSICAL_START are all configurable on
	* ppc32 and based on how they are set we determine MEMORY_START.
	*
	* For the linear mapping the following equation should be true:
	* KERNELBASE - PAGE_OFFSET = PHYSICAL_START - MEMORY_START
	*
	* Also, KERNELBASE >= PAGE_OFFSET and PHYSICAL_START >= MEMORY_START
	*
	* There are two ways to determine a physical address from a virtual one:
	* va = pa + PAGE_OFFSET - MEMORY_START
	* va = pa + KERNELBASE - PHYSICAL_START
	*
	* If you want to know something's offset from the start of the kernel you
	* should subtract KERNELBASE.
	*
	* If you want to test if something's a kernel address, use is_kernel_addr().
	*/

	#define KERNELBASE ASM_CONST(CONFIG_KERNEL_START)
	#define PAGE_OFFSET ASM_CONST(CONFIG_PAGE_OFFSET)
	#define LOAD_OFFSET ASM_CONST((CONFIG_KERNEL_START-CONFIG_PHYSICAL_START))

	#if defined(CONFIG_NONSTATIC_KERNEL)
	#ifndef __ASSEMBLY__

	extern phys_addr_t memstart_addr;
	extern phys_addr_t kernstart_addr;

	#if defined(CONFIG_RELOCATABLE) && defined(CONFIG_PPC32)
	extern long long virt_phys_offset;
	#endif

	#endif /* __ASSEMBLY__ */
	#define PHYSICAL_START kernstart_addr

	#else /* !CONFIG_NONSTATIC_KERNEL */
	#define PHYSICAL_START ASM_CONST(CONFIG_PHYSICAL_START)
	#endif

	/* See Description below for VIRT_PHYS_OFFSET */
	#if defined(CONFIG_PPC32) && defined(CONFIG_BOOKE)
	#ifdef CONFIG_RELOCATABLE
	#define VIRT_PHYS_OFFSET virt_phys_offset
	#else
	#define VIRT_PHYS_OFFSET (KERNELBASE - PHYSICAL_START)
	#endif
	#endif

	#ifdef CONFIG_PPC64
	#define MEMORY_START 0UL
	#elif defined(CONFIG_NONSTATIC_KERNEL)
	#define MEMORY_START memstart_addr
	#else
	#define MEMORY_START (PHYSICAL_START + PAGE_OFFSET - KERNELBASE)
	#endif

	#ifdef CONFIG_FLATMEM
	#define ARCH_PFN_OFFSET ((unsigned long)(MEMORY_START >> PAGE_SHIFT))
	#endif

	#define virt_to_pfn(kaddr) (__pa(kaddr) >> PAGE_SHIFT)
	#define virt_to_page(kaddr) pfn_to_page(virt_to_pfn(kaddr))
	#define pfn_to_kaddr(pfn) __va((pfn) << PAGE_SHIFT)

	#define virt_addr_valid(vaddr) ({ \
	unsigned long _addr = (unsigned long)vaddr; \
	_addr >= PAGE_OFFSET && _addr < (unsigned long)high_memory && \
	pfn_valid(virt_to_pfn(_addr)); \
	})

	/*
	* On Book-E parts we need __va to parse the device tree and we can't
	* determine MEMORY_START until then. However we can determine PHYSICAL_START
	* from information at hand (program counter, TLB lookup).
	*
	* On BookE with RELOCATABLE && PPC32
	*
	* With RELOCATABLE && PPC32, we support loading the kernel at any physical
	* address without any restriction on the page alignment.
	*
	* We find the runtime address of _stext and relocate ourselves based on
	* the following calculation:
	*
	* virtual_base = ALIGN_DOWN(KERNELBASE,256M) +
	* MODULO(_stext.run,256M)
	* and create the following mapping:
	*
	* ALIGN_DOWN(_stext.run,256M) => ALIGN_DOWN(KERNELBASE,256M)
	*
	* When we process relocations, we cannot depend on the
	* existing equation for the __va()/__pa() translations:
	*
	* __va(x) = (x) - PHYSICAL_START + KERNELBASE
	*
	* Where:
	* PHYSICAL_START = kernstart_addr = Physical address of _stext
	* KERNELBASE = Compiled virtual address of _stext.
	*
	* This formula holds true iff, kernel load address is TLB page aligned.
	*
	* In our case, we need to also account for the shift in the kernel Virtual
	* address.
	*
	* E.g.,
	*
	* Let the kernel be loaded at 64MB and KERNELBASE be 0xc0000000 (same as PAGE_OFFSET).
	* In this case, we would be mapping 0 to 0xc0000000, and kernstart_addr = 64M
	*
	* Now __va(1MB) = (0x100000) - (0x4000000) + 0xc0000000
	* = 0xbc100000 , which is wrong.
	*
	* Rather, it should be : 0xc0000000 + 0x100000 = 0xc0100000
	* according to our mapping.
	*
	* Hence we use the following formula to get the translations right:
	*
	* __va(x) = (x) - [ PHYSICAL_START - Effective KERNELBASE ]
	*
	* Where :
	* PHYSICAL_START = dynamic load address.(kernstart_addr variable)
	* Effective KERNELBASE = virtual_base =
	* = ALIGN_DOWN(KERNELBASE,256M) +
	* MODULO(PHYSICAL_START,256M)
	*
	* To make the cost of __va() / __pa() more light weight, we introduce
	* a new variable virt_phys_offset, which will hold :
	*
	* virt_phys_offset = Effective KERNELBASE - PHYSICAL_START
	* = ALIGN_DOWN(KERNELBASE,256M) -
	* ALIGN_DOWN(PHYSICALSTART,256M)
	*
	* Hence :
	*
	* __va(x) = x - PHYSICAL_START + Effective KERNELBASE
	* = x + virt_phys_offset
	*
	* and
	* __pa(x) = x + PHYSICAL_START - Effective KERNELBASE
	* = x - virt_phys_offset
	*
	* On non-Book-E PPC64 PAGE_OFFSET and MEMORY_START are constants so use
	* the other definitions for __va & __pa.
	*/
	#if defined(CONFIG_PPC32) && defined(CONFIG_BOOKE)
	#define __va(x) ((void *)(unsigned long)((phys_addr_t)(x) + VIRT_PHYS_OFFSET))
	#define __pa(x) ((phys_addr_t)(unsigned long)(x) - VIRT_PHYS_OFFSET)
	#else
	#ifdef CONFIG_PPC64

	#define VIRTUAL_WARN_ON(x) WARN_ON(IS_ENABLED(CONFIG_DEBUG_VIRTUAL) && (x))

	/*
	* gcc miscompiles (unsigned long)(&static_var) - PAGE_OFFSET
	* with -mcmodel=medium, so we use & and \| instead of - and + on 64-bit.
	* This also results in better code generation.
	*/
	#define __va(x) \
	({ \
	VIRTUAL_WARN_ON((unsigned long)(x) >= PAGE_OFFSET); \
	(void *)(unsigned long)((phys_addr_t)(x) \| PAGE_OFFSET); \
	})

	#define __pa(x) \
	({ \
	VIRTUAL_WARN_ON((unsigned long)(x) < PAGE_OFFSET); \
	(unsigned long)(x) & 0x0fffffffffffffffUL; \
	})

	#else /* 32-bit, non book E */
	#define __va(x) ((void *)(unsigned long)((phys_addr_t)(x) + PAGE_OFFSET - MEMORY_START))
	#define __pa(x) ((unsigned long)(x) - PAGE_OFFSET + MEMORY_START)
	#endif
	#endif

	/*
	* Unfortunately the PLT is in the BSS in the PPC32 ELF ABI,
	* and needs to be executable. This means the whole heap ends
	* up being executable.
	*/
	#define VM_DATA_DEFAULT_FLAGS32 VM_DATA_FLAGS_TSK_EXEC
	#define VM_DATA_DEFAULT_FLAGS64 VM_DATA_FLAGS_NON_EXEC

	#ifdef __powerpc64__
	#include <asm/page_64.h>
	#else
	#include <asm/page_32.h>
	#endif

	/*
	* Don't compare things with KERNELBASE or PAGE_OFFSET to test for
	* "kernelness", use is_kernel_addr() - it should do what you want.
	*/
	#ifdef CONFIG_PPC_BOOK3E_64
	#define is_kernel_addr(x) ((x) >= 0x8000000000000000ul)
	#elif defined(CONFIG_PPC_BOOK3S_64)
	#define is_kernel_addr(x) ((x) >= PAGE_OFFSET)
	#else
	#define is_kernel_addr(x) ((x) >= TASK_SIZE)
	#endif

	#ifndef CONFIG_PPC_BOOK3S_64
	/*
	* Use the top bit of the higher-level page table entries to indicate whether
	* the entries we point to contain hugepages. This works because we know that
	* the page tables live in kernel space. If we ever decide to support having
	* page tables at arbitrary addresses, this breaks and will have to change.
	*/
	#ifdef CONFIG_PPC64
	#define PD_HUGE 0x8000000000000000UL
	#else
	#define PD_HUGE 0x80000000
	#endif

	#else /* CONFIG_PPC_BOOK3S_64 */
	/*
	* Book3S 64 stores real addresses in the hugepd entries to
	* avoid overlaps with _PAGE_PRESENT and _PAGE_PTE.
	*/
	#define HUGEPD_ADDR_MASK (0x0ffffffffffffffful & ~HUGEPD_SHIFT_MASK)
	#endif /* CONFIG_PPC_BOOK3S_64 */

	/*
	* Some number of bits at the level of the page table that points to
	* a hugepte are used to encode the size. This masks those bits.
	* On 8xx, HW assistance requires 4k alignment for the hugepte.
	*/
	#ifdef CONFIG_PPC_8xx
	#define HUGEPD_SHIFT_MASK 0xfff
	#else
	#define HUGEPD_SHIFT_MASK 0x3f
	#endif

	#ifndef __ASSEMBLY__

	#ifdef CONFIG_PPC_BOOK3S_64
	#include <asm/pgtable-be-types.h>
	#else
	#include <asm/pgtable-types.h>
	#endif

	struct page;
	extern void clear_user_page(void page, unsigned long vaddr, struct page pg);
	extern void copy_user_page(void to, void from, unsigned long vaddr,
	struct page *p);
	extern int devmem_is_allowed(unsigned long pfn);

	#ifdef CONFIG_PPC_SMLPAR
	void arch_free_page(struct page *page, int order);
	#define HAVE_ARCH_FREE_PAGE
	#endif

	struct vm_area_struct;

	extern unsigned long kernstart_virt_addr;

	static inline unsigned long kaslr_offset(void)
	{
	return kernstart_virt_addr - KERNELBASE;
	}

	#include <asm-generic/memory_model.h>
	#endif /* __ASSEMBLY__ */

	#endif /* _ASM_POWERPC_PAGE_H */