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kernel/linux-rt-4.4.41/arch/parisc/include/asm/pgtable.h 18.8 KB
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  #ifndef _PARISC_PGTABLE_H
  #define _PARISC_PGTABLE_H
  
  #include <asm-generic/4level-fixup.h>
  
  #include <asm/fixmap.h>
  
  #ifndef __ASSEMBLY__
  /*
   * we simulate an x86-style page table for the linux mm code
   */
  
  #include <linux/bitops.h>
  #include <linux/spinlock.h>
  #include <linux/mm_types.h>
  #include <asm/processor.h>
  #include <asm/cache.h>
  
  extern spinlock_t pa_tlb_lock;
  
  /*
   * kern_addr_valid(ADDR) tests if ADDR is pointing to valid kernel
   * memory.  For the return value to be meaningful, ADDR must be >=
   * PAGE_OFFSET.  This operation can be relatively expensive (e.g.,
   * require a hash-, or multi-level tree-lookup or something of that
   * sort) but it guarantees to return TRUE only if accessing the page
   * at that address does not cause an error.  Note that there may be
   * addresses for which kern_addr_valid() returns FALSE even though an
   * access would not cause an error (e.g., this is typically true for
   * memory mapped I/O regions.
   *
   * XXX Need to implement this for parisc.
   */
  #define kern_addr_valid(addr)	(1)
  
  /* Purge data and instruction TLB entries.  Must be called holding
   * the pa_tlb_lock.  The TLB purge instructions are slow on SMP
   * machines since the purge must be broadcast to all CPUs.
   */
  
  static inline void purge_tlb_entries(struct mm_struct *mm, unsigned long addr)
  {
  	mtsp(mm->context, 1);
  	pdtlb(addr);
  	if (unlikely(split_tlb))
  		pitlb(addr);
  }
  
  /* Certain architectures need to do special things when PTEs
   * within a page table are directly modified.  Thus, the following
   * hook is made available.
   */
  #define set_pte(pteptr, pteval)                                 \
          do{                                                     \
                  *(pteptr) = (pteval);                           \
          } while(0)
  
  #define pte_inserted(x)						\
  	((pte_val(x) & (_PAGE_PRESENT|_PAGE_ACCESSED))		\
  	 == (_PAGE_PRESENT|_PAGE_ACCESSED))
  
  #define set_pte_at(mm, addr, ptep, pteval)			\
  	do {							\
  		pte_t old_pte;					\
  		unsigned long flags;				\
  		spin_lock_irqsave(&pa_tlb_lock, flags);		\
  		old_pte = *ptep;				\
  		if (pte_inserted(old_pte))			\
  			purge_tlb_entries(mm, addr);		\
  		set_pte(ptep, pteval);				\
  		spin_unlock_irqrestore(&pa_tlb_lock, flags);	\
  	} while (0)
  
  #endif /* !__ASSEMBLY__ */
  
  #include <asm/page.h>
  
  #define pte_ERROR(e) \
  	printk("%s:%d: bad pte %08lx.
  ", __FILE__, __LINE__, pte_val(e))
  #define pmd_ERROR(e) \
  	printk("%s:%d: bad pmd %08lx.
  ", __FILE__, __LINE__, (unsigned long)pmd_val(e))
  #define pgd_ERROR(e) \
  	printk("%s:%d: bad pgd %08lx.
  ", __FILE__, __LINE__, (unsigned long)pgd_val(e))
  
  /* This is the size of the initially mapped kernel memory */
  #if defined(CONFIG_64BIT)
  #define KERNEL_INITIAL_ORDER	26	/* 1<<26 = 64MB */
  #else
  #define KERNEL_INITIAL_ORDER	25	/* 1<<25 = 32MB */
  #endif
  #define KERNEL_INITIAL_SIZE	(1 << KERNEL_INITIAL_ORDER)
  
  #if CONFIG_PGTABLE_LEVELS == 3
  #define PGD_ORDER	1 /* Number of pages per pgd */
  #define PMD_ORDER	1 /* Number of pages per pmd */
  #define PGD_ALLOC_ORDER	2 /* first pgd contains pmd */
  #else
  #define PGD_ORDER	1 /* Number of pages per pgd */
  #define PGD_ALLOC_ORDER	PGD_ORDER
  #endif
  
  /* Definitions for 3rd level (we use PLD here for Page Lower directory
   * because PTE_SHIFT is used lower down to mean shift that has to be
   * done to get usable bits out of the PTE) */
  #define PLD_SHIFT	PAGE_SHIFT
  #define PLD_SIZE	PAGE_SIZE
  #define BITS_PER_PTE	(PAGE_SHIFT - BITS_PER_PTE_ENTRY)
  #define PTRS_PER_PTE    (1UL << BITS_PER_PTE)
  
  /* Definitions for 2nd level */
  #define pgtable_cache_init()	do { } while (0)
  
  #define PMD_SHIFT       (PLD_SHIFT + BITS_PER_PTE)
  #define PMD_SIZE	(1UL << PMD_SHIFT)
  #define PMD_MASK	(~(PMD_SIZE-1))
  #if CONFIG_PGTABLE_LEVELS == 3
  #define BITS_PER_PMD	(PAGE_SHIFT + PMD_ORDER - BITS_PER_PMD_ENTRY)
  #else
  #define __PAGETABLE_PMD_FOLDED
  #define BITS_PER_PMD	0
  #endif
  #define PTRS_PER_PMD    (1UL << BITS_PER_PMD)
  
  /* Definitions for 1st level */
  #define PGDIR_SHIFT	(PMD_SHIFT + BITS_PER_PMD)
  #if (PGDIR_SHIFT + PAGE_SHIFT + PGD_ORDER - BITS_PER_PGD_ENTRY) > BITS_PER_LONG
  #define BITS_PER_PGD	(BITS_PER_LONG - PGDIR_SHIFT)
  #else
  #define BITS_PER_PGD	(PAGE_SHIFT + PGD_ORDER - BITS_PER_PGD_ENTRY)
  #endif
  #define PGDIR_SIZE	(1UL << PGDIR_SHIFT)
  #define PGDIR_MASK	(~(PGDIR_SIZE-1))
  #define PTRS_PER_PGD    (1UL << BITS_PER_PGD)
  #define USER_PTRS_PER_PGD       PTRS_PER_PGD
  
  #ifdef CONFIG_64BIT
  #define MAX_ADDRBITS	(PGDIR_SHIFT + BITS_PER_PGD)
  #define MAX_ADDRESS	(1UL << MAX_ADDRBITS)
  #define SPACEID_SHIFT	(MAX_ADDRBITS - 32)
  #else
  #define MAX_ADDRBITS	(BITS_PER_LONG)
  #define MAX_ADDRESS	(1UL << MAX_ADDRBITS)
  #define SPACEID_SHIFT	0
  #endif
  
  /* This calculates the number of initial pages we need for the initial
   * page tables */
  #if (KERNEL_INITIAL_ORDER) >= (PMD_SHIFT)
  # define PT_INITIAL	(1 << (KERNEL_INITIAL_ORDER - PMD_SHIFT))
  #else
  # define PT_INITIAL	(1)  /* all initial PTEs fit into one page */
  #endif
  
  /*
   * pgd entries used up by user/kernel:
   */
  
  #define FIRST_USER_ADDRESS	0UL
  
  /* NB: The tlb miss handlers make certain assumptions about the order */
  /*     of the following bits, so be careful (One example, bits 25-31  */
  /*     are moved together in one instruction).                        */
  
  #define _PAGE_READ_BIT     31   /* (0x001) read access allowed */
  #define _PAGE_WRITE_BIT    30   /* (0x002) write access allowed */
  #define _PAGE_EXEC_BIT     29   /* (0x004) execute access allowed */
  #define _PAGE_GATEWAY_BIT  28   /* (0x008) privilege promotion allowed */
  #define _PAGE_DMB_BIT      27   /* (0x010) Data Memory Break enable (B bit) */
  #define _PAGE_DIRTY_BIT    26   /* (0x020) Page Dirty (D bit) */
  #define _PAGE_REFTRAP_BIT  25   /* (0x040) Page Ref. Trap enable (T bit) */
  #define _PAGE_NO_CACHE_BIT 24   /* (0x080) Uncached Page (U bit) */
  #define _PAGE_ACCESSED_BIT 23   /* (0x100) Software: Page Accessed */
  #define _PAGE_PRESENT_BIT  22   /* (0x200) Software: translation valid */
  #define _PAGE_HPAGE_BIT    21   /* (0x400) Software: Huge Page */
  #define _PAGE_USER_BIT     20   /* (0x800) Software: User accessible page */
  
  /* N.B. The bits are defined in terms of a 32 bit word above, so the */
  /*      following macro is ok for both 32 and 64 bit.                */
  
  #define xlate_pabit(x) (31 - x)
  
  /* this defines the shift to the usable bits in the PTE it is set so
   * that the valid bits _PAGE_PRESENT_BIT and _PAGE_USER_BIT are set
   * to zero */
  #define PTE_SHIFT	   	xlate_pabit(_PAGE_USER_BIT)
  
  /* PFN_PTE_SHIFT defines the shift of a PTE value to access the PFN field */
  #define PFN_PTE_SHIFT		12
  
  #define _PAGE_READ     (1 << xlate_pabit(_PAGE_READ_BIT))
  #define _PAGE_WRITE    (1 << xlate_pabit(_PAGE_WRITE_BIT))
  #define _PAGE_RW       (_PAGE_READ | _PAGE_WRITE)
  #define _PAGE_EXEC     (1 << xlate_pabit(_PAGE_EXEC_BIT))
  #define _PAGE_GATEWAY  (1 << xlate_pabit(_PAGE_GATEWAY_BIT))
  #define _PAGE_DMB      (1 << xlate_pabit(_PAGE_DMB_BIT))
  #define _PAGE_DIRTY    (1 << xlate_pabit(_PAGE_DIRTY_BIT))
  #define _PAGE_REFTRAP  (1 << xlate_pabit(_PAGE_REFTRAP_BIT))
  #define _PAGE_NO_CACHE (1 << xlate_pabit(_PAGE_NO_CACHE_BIT))
  #define _PAGE_ACCESSED (1 << xlate_pabit(_PAGE_ACCESSED_BIT))
  #define _PAGE_PRESENT  (1 << xlate_pabit(_PAGE_PRESENT_BIT))
  #define _PAGE_HUGE     (1 << xlate_pabit(_PAGE_HPAGE_BIT))
  #define _PAGE_USER     (1 << xlate_pabit(_PAGE_USER_BIT))
  
  #define _PAGE_TABLE	(_PAGE_PRESENT | _PAGE_READ | _PAGE_WRITE |  _PAGE_DIRTY | _PAGE_ACCESSED)
  #define _PAGE_CHG_MASK	(PAGE_MASK | _PAGE_ACCESSED | _PAGE_DIRTY)
  #define _PAGE_KERNEL_RO	(_PAGE_PRESENT | _PAGE_READ | _PAGE_DIRTY | _PAGE_ACCESSED)
  #define _PAGE_KERNEL_EXEC	(_PAGE_KERNEL_RO | _PAGE_EXEC)
  #define _PAGE_KERNEL_RWX	(_PAGE_KERNEL_EXEC | _PAGE_WRITE)
  #define _PAGE_KERNEL		(_PAGE_KERNEL_RO | _PAGE_WRITE)
  
  /* The pgd/pmd contains a ptr (in phys addr space); since all pgds/pmds
   * are page-aligned, we don't care about the PAGE_OFFSET bits, except
   * for a few meta-information bits, so we shift the address to be
   * able to effectively address 40/42/44-bits of physical address space
   * depending on 4k/16k/64k PAGE_SIZE */
  #define _PxD_PRESENT_BIT   31
  #define _PxD_ATTACHED_BIT  30
  #define _PxD_VALID_BIT     29
  
  #define PxD_FLAG_PRESENT  (1 << xlate_pabit(_PxD_PRESENT_BIT))
  #define PxD_FLAG_ATTACHED (1 << xlate_pabit(_PxD_ATTACHED_BIT))
  #define PxD_FLAG_VALID    (1 << xlate_pabit(_PxD_VALID_BIT))
  #define PxD_FLAG_MASK     (0xf)
  #define PxD_FLAG_SHIFT    (4)
  #define PxD_VALUE_SHIFT   (PFN_PTE_SHIFT-PxD_FLAG_SHIFT)
  
  #ifndef __ASSEMBLY__
  
  #define PAGE_NONE	__pgprot(_PAGE_PRESENT | _PAGE_USER | _PAGE_ACCESSED)
  #define PAGE_SHARED	__pgprot(_PAGE_PRESENT | _PAGE_USER | _PAGE_READ | _PAGE_WRITE | _PAGE_ACCESSED)
  /* Others seem to make this executable, I don't know if that's correct
     or not.  The stack is mapped this way though so this is necessary
     in the short term - dhd@linuxcare.com, 2000-08-08 */
  #define PAGE_READONLY	__pgprot(_PAGE_PRESENT | _PAGE_USER | _PAGE_READ | _PAGE_ACCESSED)
  #define PAGE_WRITEONLY  __pgprot(_PAGE_PRESENT | _PAGE_USER | _PAGE_WRITE | _PAGE_ACCESSED)
  #define PAGE_EXECREAD   __pgprot(_PAGE_PRESENT | _PAGE_USER | _PAGE_READ | _PAGE_EXEC |_PAGE_ACCESSED)
  #define PAGE_COPY       PAGE_EXECREAD
  #define PAGE_RWX        __pgprot(_PAGE_PRESENT | _PAGE_USER | _PAGE_READ | _PAGE_WRITE | _PAGE_EXEC |_PAGE_ACCESSED)
  #define PAGE_KERNEL	__pgprot(_PAGE_KERNEL)
  #define PAGE_KERNEL_EXEC	__pgprot(_PAGE_KERNEL_EXEC)
  #define PAGE_KERNEL_RWX	__pgprot(_PAGE_KERNEL_RWX)
  #define PAGE_KERNEL_RO	__pgprot(_PAGE_KERNEL_RO)
  #define PAGE_KERNEL_UNC	__pgprot(_PAGE_KERNEL | _PAGE_NO_CACHE)
  #define PAGE_GATEWAY    __pgprot(_PAGE_PRESENT | _PAGE_USER | _PAGE_ACCESSED | _PAGE_GATEWAY| _PAGE_READ)
  
  
  /*
   * We could have an execute only page using "gateway - promote to priv
   * level 3", but that is kind of silly. So, the way things are defined
   * now, we must always have read permission for pages with execute
   * permission. For the fun of it we'll go ahead and support write only
   * pages.
   */
  
  	 /*xwr*/
  #define __P000  PAGE_NONE
  #define __P001  PAGE_READONLY
  #define __P010  __P000 /* copy on write */
  #define __P011  __P001 /* copy on write */
  #define __P100  PAGE_EXECREAD
  #define __P101  PAGE_EXECREAD
  #define __P110  __P100 /* copy on write */
  #define __P111  __P101 /* copy on write */
  
  #define __S000  PAGE_NONE
  #define __S001  PAGE_READONLY
  #define __S010  PAGE_WRITEONLY
  #define __S011  PAGE_SHARED
  #define __S100  PAGE_EXECREAD
  #define __S101  PAGE_EXECREAD
  #define __S110  PAGE_RWX
  #define __S111  PAGE_RWX
  
  
  extern pgd_t swapper_pg_dir[]; /* declared in init_task.c */
  
  /* initial page tables for 0-8MB for kernel */
  
  extern pte_t pg0[];
  
  /* zero page used for uninitialized stuff */
  
  extern unsigned long *empty_zero_page;
  
  /*
   * ZERO_PAGE is a global shared page that is always zero: used
   * for zero-mapped memory areas etc..
   */
  
  #define ZERO_PAGE(vaddr) (virt_to_page(empty_zero_page))
  
  #define pte_none(x)     (pte_val(x) == 0)
  #define pte_present(x)	(pte_val(x) & _PAGE_PRESENT)
  #define pte_clear(mm, addr, xp)  set_pte_at(mm, addr, xp, __pte(0))
  
  #define pmd_flag(x)	(pmd_val(x) & PxD_FLAG_MASK)
  #define pmd_address(x)	((unsigned long)(pmd_val(x) &~ PxD_FLAG_MASK) << PxD_VALUE_SHIFT)
  #define pgd_flag(x)	(pgd_val(x) & PxD_FLAG_MASK)
  #define pgd_address(x)	((unsigned long)(pgd_val(x) &~ PxD_FLAG_MASK) << PxD_VALUE_SHIFT)
  
  #if CONFIG_PGTABLE_LEVELS == 3
  /* The first entry of the permanent pmd is not there if it contains
   * the gateway marker */
  #define pmd_none(x)	(!pmd_val(x) || pmd_flag(x) == PxD_FLAG_ATTACHED)
  #else
  #define pmd_none(x)	(!pmd_val(x))
  #endif
  #define pmd_bad(x)	(!(pmd_flag(x) & PxD_FLAG_VALID))
  #define pmd_present(x)	(pmd_flag(x) & PxD_FLAG_PRESENT)
  static inline void pmd_clear(pmd_t *pmd) {
  #if CONFIG_PGTABLE_LEVELS == 3
  	if (pmd_flag(*pmd) & PxD_FLAG_ATTACHED)
  		/* This is the entry pointing to the permanent pmd
  		 * attached to the pgd; cannot clear it */
  		__pmd_val_set(*pmd, PxD_FLAG_ATTACHED);
  	else
  #endif
  		__pmd_val_set(*pmd,  0);
  }
  
  
  
  #if CONFIG_PGTABLE_LEVELS == 3
  #define pgd_page_vaddr(pgd) ((unsigned long) __va(pgd_address(pgd)))
  #define pgd_page(pgd)	virt_to_page((void *)pgd_page_vaddr(pgd))
  
  /* For 64 bit we have three level tables */
  
  #define pgd_none(x)     (!pgd_val(x))
  #define pgd_bad(x)      (!(pgd_flag(x) & PxD_FLAG_VALID))
  #define pgd_present(x)  (pgd_flag(x) & PxD_FLAG_PRESENT)
  static inline void pgd_clear(pgd_t *pgd) {
  #if CONFIG_PGTABLE_LEVELS == 3
  	if(pgd_flag(*pgd) & PxD_FLAG_ATTACHED)
  		/* This is the permanent pmd attached to the pgd; cannot
  		 * free it */
  		return;
  #endif
  	__pgd_val_set(*pgd, 0);
  }
  #else
  /*
   * The "pgd_xxx()" functions here are trivial for a folded two-level
   * setup: the pgd is never bad, and a pmd always exists (as it's folded
   * into the pgd entry)
   */
  static inline int pgd_none(pgd_t pgd)		{ return 0; }
  static inline int pgd_bad(pgd_t pgd)		{ return 0; }
  static inline int pgd_present(pgd_t pgd)	{ return 1; }
  static inline void pgd_clear(pgd_t * pgdp)	{ }
  #endif
  
  /*
   * The following only work if pte_present() is true.
   * Undefined behaviour if not..
   */
  static inline int pte_dirty(pte_t pte)		{ return pte_val(pte) & _PAGE_DIRTY; }
  static inline int pte_young(pte_t pte)		{ return pte_val(pte) & _PAGE_ACCESSED; }
  static inline int pte_write(pte_t pte)		{ return pte_val(pte) & _PAGE_WRITE; }
  static inline int pte_special(pte_t pte)	{ return 0; }
  
  static inline pte_t pte_mkclean(pte_t pte)	{ pte_val(pte) &= ~_PAGE_DIRTY; return pte; }
  static inline pte_t pte_mkold(pte_t pte)	{ pte_val(pte) &= ~_PAGE_ACCESSED; return pte; }
  static inline pte_t pte_wrprotect(pte_t pte)	{ pte_val(pte) &= ~_PAGE_WRITE; return pte; }
  static inline pte_t pte_mkdirty(pte_t pte)	{ pte_val(pte) |= _PAGE_DIRTY; return pte; }
  static inline pte_t pte_mkyoung(pte_t pte)	{ pte_val(pte) |= _PAGE_ACCESSED; return pte; }
  static inline pte_t pte_mkwrite(pte_t pte)	{ pte_val(pte) |= _PAGE_WRITE; return pte; }
  static inline pte_t pte_mkspecial(pte_t pte)	{ return pte; }
  
  /*
   * Huge pte definitions.
   */
  #ifdef CONFIG_HUGETLB_PAGE
  #define pte_huge(pte)           (pte_val(pte) & _PAGE_HUGE)
  #define pte_mkhuge(pte)         (__pte(pte_val(pte) | \
  				 (parisc_requires_coherency() ? 0 : _PAGE_HUGE)))
  #else
  #define pte_huge(pte)           (0)
  #define pte_mkhuge(pte)         (pte)
  #endif
  
  
  /*
   * Conversion functions: convert a page and protection to a page entry,
   * and a page entry and page directory to the page they refer to.
   */
  #define __mk_pte(addr,pgprot) \
  ({									\
  	pte_t __pte;							\
  									\
  	pte_val(__pte) = ((((addr)>>PAGE_SHIFT)<<PFN_PTE_SHIFT) + pgprot_val(pgprot));	\
  									\
  	__pte;								\
  })
  
  #define mk_pte(page, pgprot)	pfn_pte(page_to_pfn(page), (pgprot))
  
  static inline pte_t pfn_pte(unsigned long pfn, pgprot_t pgprot)
  {
  	pte_t pte;
  	pte_val(pte) = (pfn << PFN_PTE_SHIFT) | pgprot_val(pgprot);
  	return pte;
  }
  
  static inline pte_t pte_modify(pte_t pte, pgprot_t newprot)
  { pte_val(pte) = (pte_val(pte) & _PAGE_CHG_MASK) | pgprot_val(newprot); return pte; }
  
  /* Permanent address of a page.  On parisc we don't have highmem. */
  
  #define pte_pfn(x)		(pte_val(x) >> PFN_PTE_SHIFT)
  
  #define pte_page(pte)		(pfn_to_page(pte_pfn(pte)))
  
  #define pmd_page_vaddr(pmd)	((unsigned long) __va(pmd_address(pmd)))
  
  #define __pmd_page(pmd) ((unsigned long) __va(pmd_address(pmd)))
  #define pmd_page(pmd)	virt_to_page((void *)__pmd_page(pmd))
  
  #define pgd_index(address) ((address) >> PGDIR_SHIFT)
  
  /* to find an entry in a page-table-directory */
  #define pgd_offset(mm, address) \
  ((mm)->pgd + ((address) >> PGDIR_SHIFT))
  
  /* to find an entry in a kernel page-table-directory */
  #define pgd_offset_k(address) pgd_offset(&init_mm, address)
  
  /* Find an entry in the second-level page table.. */
  
  #if CONFIG_PGTABLE_LEVELS == 3
  #define pmd_index(addr)         (((addr) >> PMD_SHIFT) & (PTRS_PER_PMD - 1))
  #define pmd_offset(dir,address) \
  ((pmd_t *) pgd_page_vaddr(*(dir)) + pmd_index(address))
  #else
  #define pmd_offset(dir,addr) ((pmd_t *) dir)
  #endif
  
  /* Find an entry in the third-level page table.. */ 
  #define pte_index(address) (((address) >> PAGE_SHIFT) & (PTRS_PER_PTE-1))
  #define pte_offset_kernel(pmd, address) \
  	((pte_t *) pmd_page_vaddr(*(pmd)) + pte_index(address))
  #define pte_offset_map(pmd, address) pte_offset_kernel(pmd, address)
  #define pte_unmap(pte) do { } while (0)
  
  #define pte_unmap(pte)			do { } while (0)
  #define pte_unmap_nested(pte)		do { } while (0)
  
  extern void paging_init (void);
  
  /* Used for deferring calls to flush_dcache_page() */
  
  #define PG_dcache_dirty         PG_arch_1
  
  extern void update_mmu_cache(struct vm_area_struct *, unsigned long, pte_t *);
  
  /* Encode and de-code a swap entry */
  
  #define __swp_type(x)                     ((x).val & 0x1f)
  #define __swp_offset(x)                   ( (((x).val >> 6) &  0x7) | \
  					  (((x).val >> 8) & ~0x7) )
  #define __swp_entry(type, offset)         ((swp_entry_t) { (type) | \
  					    ((offset &  0x7) << 6) | \
  					    ((offset & ~0x7) << 8) })
  #define __pte_to_swp_entry(pte)		((swp_entry_t) { pte_val(pte) })
  #define __swp_entry_to_pte(x)		((pte_t) { (x).val })
  
  static inline int ptep_test_and_clear_young(struct vm_area_struct *vma, unsigned long addr, pte_t *ptep)
  {
  	pte_t pte;
  	unsigned long flags;
  
  	if (!pte_young(*ptep))
  		return 0;
  
  	spin_lock_irqsave(&pa_tlb_lock, flags);
  	pte = *ptep;
  	if (!pte_young(pte)) {
  		spin_unlock_irqrestore(&pa_tlb_lock, flags);
  		return 0;
  	}
  	purge_tlb_entries(vma->vm_mm, addr);
  	set_pte(ptep, pte_mkold(pte));
  	spin_unlock_irqrestore(&pa_tlb_lock, flags);
  	return 1;
  }
  
  struct mm_struct;
  static inline pte_t ptep_get_and_clear(struct mm_struct *mm, unsigned long addr, pte_t *ptep)
  {
  	pte_t old_pte;
  	unsigned long flags;
  
  	spin_lock_irqsave(&pa_tlb_lock, flags);
  	old_pte = *ptep;
  	if (pte_inserted(old_pte))
  		purge_tlb_entries(mm, addr);
  	set_pte(ptep, __pte(0));
  	spin_unlock_irqrestore(&pa_tlb_lock, flags);
  
  	return old_pte;
  }
  
  static inline void ptep_set_wrprotect(struct mm_struct *mm, unsigned long addr, pte_t *ptep)
  {
  	unsigned long flags;
  	spin_lock_irqsave(&pa_tlb_lock, flags);
  	purge_tlb_entries(mm, addr);
  	set_pte(ptep, pte_wrprotect(*ptep));
  	spin_unlock_irqrestore(&pa_tlb_lock, flags);
  }
  
  #define pte_same(A,B)	(pte_val(A) == pte_val(B))
  
  #endif /* !__ASSEMBLY__ */
  
  
  /* TLB page size encoding - see table 3-1 in parisc20.pdf */
  #define _PAGE_SIZE_ENCODING_4K		0
  #define _PAGE_SIZE_ENCODING_16K		1
  #define _PAGE_SIZE_ENCODING_64K		2
  #define _PAGE_SIZE_ENCODING_256K	3
  #define _PAGE_SIZE_ENCODING_1M		4
  #define _PAGE_SIZE_ENCODING_4M		5
  #define _PAGE_SIZE_ENCODING_16M		6
  #define _PAGE_SIZE_ENCODING_64M		7
  
  #if defined(CONFIG_PARISC_PAGE_SIZE_4KB)
  # define _PAGE_SIZE_ENCODING_DEFAULT _PAGE_SIZE_ENCODING_4K
  #elif defined(CONFIG_PARISC_PAGE_SIZE_16KB)
  # define _PAGE_SIZE_ENCODING_DEFAULT _PAGE_SIZE_ENCODING_16K
  #elif defined(CONFIG_PARISC_PAGE_SIZE_64KB)
  # define _PAGE_SIZE_ENCODING_DEFAULT _PAGE_SIZE_ENCODING_64K
  #endif
  
  
  #define pgprot_noncached(prot) __pgprot(pgprot_val(prot) | _PAGE_NO_CACHE)
  
  /* We provide our own get_unmapped_area to provide cache coherency */
  
  #define HAVE_ARCH_UNMAPPED_AREA
  #define HAVE_ARCH_UNMAPPED_AREA_TOPDOWN
  
  #define __HAVE_ARCH_PTEP_TEST_AND_CLEAR_YOUNG
  #define __HAVE_ARCH_PTEP_GET_AND_CLEAR
  #define __HAVE_ARCH_PTEP_SET_WRPROTECT
  #define __HAVE_ARCH_PTE_SAME
  #include <asm-generic/pgtable.h>
  
  #endif /* _PARISC_PGTABLE_H */