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a4fe3ce769
Currently each available hugepage size uses a slightly different pagetable layout: that is, the bottem level table of pointers to hugepages is a different size, and may branch off from the normal page tables at a different level. Every hugepage aware path that needs to walk the pagetables must therefore look up the hugepage size from the slice info first, and work out the correct way to walk the pagetables accordingly. Future hardware is likely to add more possible hugepage sizes, more layout options and more mess. This patch, therefore reworks the handling of hugepage pagetables to reduce this complexity. In the new scheme, instead of having to consult the slice mask, pagetable walking code can check a flag in the PGD/PUD/PMD entries to see where to branch off to hugepage pagetables, and the entry also contains the information (eseentially hugepage shift) necessary to then interpret that table without recourse to the slice mask. This scheme can be extended neatly to handle multiple levels of self-describing "special" hugepage pagetables, although for now we assume only one level exists. This approach means that only the pagetable allocation path needs to know how the pagetables should be set out. All other (hugepage) pagetable walking paths can just interpret the structure as they go. There already was a flag bit in PGD/PUD/PMD entries for hugepage directory pointers, but it was only used for debug. We alter that flag bit to instead be a 0 in the MSB to indicate a hugepage pagetable pointer (normally it would be 1 since the pointer lies in the linear mapping). This means that asm pagetable walking can test for (and punt on) hugepage pointers with the same test that checks for unpopulated page directory entries (beq becomes bge), since hugepage pointers will always be positive, and normal pointers always negative. While we're at it, we get rid of the confusing (and grep defeating) #defining of hugepte_shift to be the same thing as mmu_huge_psizes. Signed-off-by: David Gibson <dwg@au1.ibm.com> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
265 lines
7.3 KiB
C
265 lines
7.3 KiB
C
#ifndef _ASM_POWERPC_PAGE_H
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#define _ASM_POWERPC_PAGE_H
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/*
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* Copyright (C) 2001,2005 IBM Corporation.
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version
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* 2 of the License, or (at your option) any later version.
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*/
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#ifndef __ASSEMBLY__
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#include <linux/types.h>
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#else
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#include <asm/types.h>
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#endif
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#include <asm/asm-compat.h>
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#include <asm/kdump.h>
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/*
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* On regular PPC32 page size is 4K (but we support 4K/16K/64K/256K pages
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* on PPC44x). For PPC64 we support either 4K or 64K software
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* page size. When using 64K pages however, whether we are really supporting
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* 64K pages in HW or not is irrelevant to those definitions.
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*/
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#if defined(CONFIG_PPC_256K_PAGES)
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#define PAGE_SHIFT 18
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#elif defined(CONFIG_PPC_64K_PAGES)
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#define PAGE_SHIFT 16
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#elif defined(CONFIG_PPC_16K_PAGES)
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#define PAGE_SHIFT 14
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#else
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#define PAGE_SHIFT 12
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#endif
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#define PAGE_SIZE (ASM_CONST(1) << PAGE_SHIFT)
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/* We do define AT_SYSINFO_EHDR but don't use the gate mechanism */
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#define __HAVE_ARCH_GATE_AREA 1
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/*
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* Subtle: (1 << PAGE_SHIFT) is an int, not an unsigned long. So if we
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* assign PAGE_MASK to a larger type it gets extended the way we want
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* (i.e. with 1s in the high bits)
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*/
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#define PAGE_MASK (~((1 << PAGE_SHIFT) - 1))
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/*
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* KERNELBASE is the virtual address of the start of the kernel, it's often
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* the same as PAGE_OFFSET, but _might not be_.
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*
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* The kdump dump kernel is one example where KERNELBASE != PAGE_OFFSET.
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*
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* PAGE_OFFSET is the virtual address of the start of lowmem.
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*
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* PHYSICAL_START is the physical address of the start of the kernel.
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*
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* MEMORY_START is the physical address of the start of lowmem.
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*
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* KERNELBASE, PAGE_OFFSET, and PHYSICAL_START are all configurable on
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* ppc32 and based on how they are set we determine MEMORY_START.
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*
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* For the linear mapping the following equation should be true:
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* KERNELBASE - PAGE_OFFSET = PHYSICAL_START - MEMORY_START
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*
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* Also, KERNELBASE >= PAGE_OFFSET and PHYSICAL_START >= MEMORY_START
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*
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* There are two was to determine a physical address from a virtual one:
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* va = pa + PAGE_OFFSET - MEMORY_START
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* va = pa + KERNELBASE - PHYSICAL_START
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*
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* If you want to know something's offset from the start of the kernel you
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* should subtract KERNELBASE.
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*
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* If you want to test if something's a kernel address, use is_kernel_addr().
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*/
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#define KERNELBASE ASM_CONST(CONFIG_KERNEL_START)
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#define PAGE_OFFSET ASM_CONST(CONFIG_PAGE_OFFSET)
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#define LOAD_OFFSET ASM_CONST((CONFIG_KERNEL_START-CONFIG_PHYSICAL_START))
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#if defined(CONFIG_RELOCATABLE)
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#ifndef __ASSEMBLY__
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extern phys_addr_t memstart_addr;
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extern phys_addr_t kernstart_addr;
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#endif
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#define PHYSICAL_START kernstart_addr
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#else
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#define PHYSICAL_START ASM_CONST(CONFIG_PHYSICAL_START)
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#endif
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#ifdef CONFIG_PPC64
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#define MEMORY_START 0UL
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#elif defined(CONFIG_RELOCATABLE)
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#define MEMORY_START memstart_addr
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#else
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#define MEMORY_START (PHYSICAL_START + PAGE_OFFSET - KERNELBASE)
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#endif
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#ifdef CONFIG_FLATMEM
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#define ARCH_PFN_OFFSET (MEMORY_START >> PAGE_SHIFT)
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#define pfn_valid(pfn) ((pfn) >= ARCH_PFN_OFFSET && (pfn) < (ARCH_PFN_OFFSET + max_mapnr))
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#endif
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#define virt_to_page(kaddr) pfn_to_page(__pa(kaddr) >> PAGE_SHIFT)
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#define pfn_to_kaddr(pfn) __va((pfn) << PAGE_SHIFT)
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#define virt_addr_valid(kaddr) pfn_valid(__pa(kaddr) >> PAGE_SHIFT)
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#define __va(x) ((void *)((unsigned long)(x) + PAGE_OFFSET - MEMORY_START))
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#define __pa(x) ((unsigned long)(x) - PAGE_OFFSET + MEMORY_START)
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/*
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* Unfortunately the PLT is in the BSS in the PPC32 ELF ABI,
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* and needs to be executable. This means the whole heap ends
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* up being executable.
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*/
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#define VM_DATA_DEFAULT_FLAGS32 (VM_READ | VM_WRITE | VM_EXEC | \
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VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC)
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#define VM_DATA_DEFAULT_FLAGS64 (VM_READ | VM_WRITE | \
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VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC)
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#ifdef __powerpc64__
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#include <asm/page_64.h>
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#else
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#include <asm/page_32.h>
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#endif
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/* align addr on a size boundary - adjust address up/down if needed */
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#define _ALIGN_UP(addr,size) (((addr)+((size)-1))&(~((size)-1)))
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#define _ALIGN_DOWN(addr,size) ((addr)&(~((size)-1)))
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/* align addr on a size boundary - adjust address up if needed */
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#define _ALIGN(addr,size) _ALIGN_UP(addr,size)
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/*
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* Don't compare things with KERNELBASE or PAGE_OFFSET to test for
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* "kernelness", use is_kernel_addr() - it should do what you want.
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*/
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#ifdef CONFIG_PPC_BOOK3E_64
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#define is_kernel_addr(x) ((x) >= 0x8000000000000000ul)
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#else
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#define is_kernel_addr(x) ((x) >= PAGE_OFFSET)
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#endif
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#ifndef __ASSEMBLY__
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#undef STRICT_MM_TYPECHECKS
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#ifdef STRICT_MM_TYPECHECKS
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/* These are used to make use of C type-checking. */
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/* PTE level */
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typedef struct { pte_basic_t pte; } pte_t;
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#define pte_val(x) ((x).pte)
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#define __pte(x) ((pte_t) { (x) })
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/* 64k pages additionally define a bigger "real PTE" type that gathers
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* the "second half" part of the PTE for pseudo 64k pages
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*/
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#if defined(CONFIG_PPC_64K_PAGES) && defined(CONFIG_PPC_STD_MMU_64)
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typedef struct { pte_t pte; unsigned long hidx; } real_pte_t;
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#else
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typedef struct { pte_t pte; } real_pte_t;
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#endif
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/* PMD level */
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#ifdef CONFIG_PPC64
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typedef struct { unsigned long pmd; } pmd_t;
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#define pmd_val(x) ((x).pmd)
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#define __pmd(x) ((pmd_t) { (x) })
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/* PUD level exusts only on 4k pages */
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#ifndef CONFIG_PPC_64K_PAGES
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typedef struct { unsigned long pud; } pud_t;
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#define pud_val(x) ((x).pud)
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#define __pud(x) ((pud_t) { (x) })
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#endif /* !CONFIG_PPC_64K_PAGES */
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#endif /* CONFIG_PPC64 */
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/* PGD level */
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typedef struct { unsigned long pgd; } pgd_t;
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#define pgd_val(x) ((x).pgd)
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#define __pgd(x) ((pgd_t) { (x) })
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/* Page protection bits */
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typedef struct { unsigned long pgprot; } pgprot_t;
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#define pgprot_val(x) ((x).pgprot)
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#define __pgprot(x) ((pgprot_t) { (x) })
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#else
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/*
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* .. while these make it easier on the compiler
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*/
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typedef pte_basic_t pte_t;
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#define pte_val(x) (x)
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#define __pte(x) (x)
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#if defined(CONFIG_PPC_64K_PAGES) && defined(CONFIG_PPC_STD_MMU_64)
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typedef struct { pte_t pte; unsigned long hidx; } real_pte_t;
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#else
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typedef pte_t real_pte_t;
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#endif
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#ifdef CONFIG_PPC64
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typedef unsigned long pmd_t;
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#define pmd_val(x) (x)
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#define __pmd(x) (x)
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#ifndef CONFIG_PPC_64K_PAGES
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typedef unsigned long pud_t;
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#define pud_val(x) (x)
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#define __pud(x) (x)
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#endif /* !CONFIG_PPC_64K_PAGES */
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#endif /* CONFIG_PPC64 */
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typedef unsigned long pgd_t;
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#define pgd_val(x) (x)
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#define pgprot_val(x) (x)
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typedef unsigned long pgprot_t;
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#define __pgd(x) (x)
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#define __pgprot(x) (x)
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#endif
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typedef struct { signed long pd; } hugepd_t;
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#define HUGEPD_SHIFT_MASK 0x3f
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#ifdef CONFIG_HUGETLB_PAGE
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static inline int hugepd_ok(hugepd_t hpd)
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{
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return (hpd.pd > 0);
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}
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#define is_hugepd(pdep) (hugepd_ok(*((hugepd_t *)(pdep))))
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#else /* CONFIG_HUGETLB_PAGE */
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#define is_hugepd(pdep) 0
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#endif /* CONFIG_HUGETLB_PAGE */
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struct page;
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extern void clear_user_page(void *page, unsigned long vaddr, struct page *pg);
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extern void copy_user_page(void *to, void *from, unsigned long vaddr,
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struct page *p);
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extern int page_is_ram(unsigned long pfn);
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#ifdef CONFIG_PPC_SMLPAR
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void arch_free_page(struct page *page, int order);
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#define HAVE_ARCH_FREE_PAGE
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#endif
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struct vm_area_struct;
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typedef struct page *pgtable_t;
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#include <asm-generic/memory_model.h>
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#endif /* __ASSEMBLY__ */
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#endif /* _ASM_POWERPC_PAGE_H */
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