include/asm-sh/pgtable.h

/*
 * This file contains the functions and defines necessary to modify and
 * use the SuperH page table tree.
 *
 * Copyright (C) 1999 Niibe Yutaka
 * Copyright (C) 2002 - 2005 Paul Mundt
 *
 * This file is subject to the terms and conditions of the GNU General
 * Public License.  See the file "COPYING" in the main directory of this
 * archive for more details.
 */
#ifndef __ASM_SH_PGTABLE_H
#define __ASM_SH_PGTABLE_H

#include <asm-generic/pgtable-nopmd.h>
#include <asm/page.h>

#ifndef __ASSEMBLY__
#include <asm/addrspace.h>
#include <asm/fixmap.h>

/*
 * ZERO_PAGE is a global shared page that is always zero: used
 * for zero-mapped memory areas etc..
 */
extern unsigned long empty_zero_page[PAGE_SIZE / sizeof(unsigned long)];
#define ZERO_PAGE(vaddr) (virt_to_page(empty_zero_page))

#endif /* !__ASSEMBLY__ */

/*
 * Effective and physical address definitions, to aid with sign
 * extension.
 */
#define NEFF		32
#define	NEFF_SIGN	(1LL << (NEFF - 1))
#define	NEFF_MASK	(-1LL << NEFF)

#ifdef CONFIG_29BIT
#define NPHYS		29
#else
#define NPHYS		32
#endif

#define	NPHYS_SIGN	(1LL << (NPHYS - 1))
#define	NPHYS_MASK	(-1LL << NPHYS)

/*
 * traditional two-level paging structure
 */
/* PTE bits */
#ifdef CONFIG_X2TLB
# define PTE_MAGNITUDE	3	/* 64-bit PTEs on extended mode SH-X2 TLB */
#else
# define PTE_MAGNITUDE	2	/* 32-bit PTEs */
#endif
#define PTE_SHIFT	PAGE_SHIFT
#define PTE_BITS	(PTE_SHIFT - PTE_MAGNITUDE)

/* PGD bits */
#define PGDIR_SHIFT	(PTE_SHIFT + PTE_BITS)
#define PGDIR_SIZE	(1UL << PGDIR_SHIFT)
#define PGDIR_MASK	(~(PGDIR_SIZE-1))

/* Entries per level */
#define PTRS_PER_PTE	(PAGE_SIZE / (1 << PTE_MAGNITUDE))
#define PTRS_PER_PGD	(PAGE_SIZE / sizeof(pgd_t))

#define USER_PTRS_PER_PGD	(TASK_SIZE/PGDIR_SIZE)
#define FIRST_USER_ADDRESS	0

#define PTE_PHYS_MASK		(0x20000000 - PAGE_SIZE)

#define VMALLOC_START	(P3SEG)
#define VMALLOC_END	(FIXADDR_START-2*PAGE_SIZE)

/*
 * Linux PTEL encoding.
 *
 * Hardware and software bit definitions for the PTEL value (see below for
 * notes on SH-X2 MMUs and 64-bit PTEs):
 *
 * - Bits 0 and 7 are reserved on SH-3 (_PAGE_WT and _PAGE_SZ1 on SH-4).
 *
 * - Bit 1 is the SH-bit, but is unused on SH-3 due to an MMU bug (the
 *   hardware PTEL value can't have the SH-bit set when MMUCR.IX is set,
 *   which is the default in cpu-sh3/mmu_context.h:MMU_CONTROL_INIT).
 *
 *   In order to keep this relatively clean, do not use these for defining
 *   SH-3 specific flags until all of the other unused bits have been
 *   exhausted.
 *
 * - Bit 9 is reserved by everyone and used by _PAGE_PROTNONE.
 *
 * - Bits 10 and 11 are low bits of the PPN that are reserved on >= 4K pages.
 *   Bit 10 is used for _PAGE_ACCESSED, bit 11 remains unused.
 *
 * - Bits 31, 30, and 29 remain unused by everyone and can be used for future
 *   software flags, although care must be taken to update _PAGE_CLEAR_FLAGS.
 *
 * XXX: Leave the _PAGE_FILE and _PAGE_WT overhaul for a rainy day.
 *
 * SH-X2 MMUs and extended PTEs
 *
 * SH-X2 supports an extended mode TLB with split data arrays due to the
 * number of bits needed for PR and SZ (now EPR and ESZ) encodings. The PR and
 * SZ bit placeholders still exist in data array 1, but are implemented as
 * reserved bits, with the real logic existing in data array 2.
 *
 * The downside to this is that we can no longer fit everything in to a 32-bit
 * PTE encoding, so a 64-bit pte_t is necessary for these parts. On the plus
 * side, this gives us quite a few spare bits to play with for future usage.
 */
/* Legacy and compat mode bits */
#define	_PAGE_WT	0x001		/* WT-bit on SH-4, 0 on SH-3 */
#define _PAGE_HW_SHARED	0x002		/* SH-bit  : shared among processes */
#define _PAGE_DIRTY	0x004		/* D-bit   : page changed */
#define _PAGE_CACHABLE	0x008		/* C-bit   : cachable */
#define _PAGE_SZ0	0x010		/* SZ0-bit : Size of page */
#define _PAGE_RW	0x020		/* PR0-bit : write access allowed */
#define _PAGE_USER	0x040		/* PR1-bit : user space access allowed*/
#define _PAGE_SZ1	0x080		/* SZ1-bit : Size of page (on SH-4) */
#define _PAGE_PRESENT	0x100		/* V-bit   : page is valid */
#define _PAGE_PROTNONE	0x200		/* software: if not present  */
#define _PAGE_ACCESSED	0x400		/* software: page referenced */
#define _PAGE_FILE	_PAGE_WT	/* software: pagecache or swap? */

#define _PAGE_SZ_MASK	(_PAGE_SZ0 | _PAGE_SZ1)
#define _PAGE_PR_MASK	(_PAGE_RW | _PAGE_USER)

/* Extended mode bits */
#define _PAGE_EXT_ESZ0		0x0010	/* ESZ0-bit: Size of page */
#define _PAGE_EXT_ESZ1		0x0020	/* ESZ1-bit: Size of page */
#define _PAGE_EXT_ESZ2		0x0040	/* ESZ2-bit: Size of page */
#define _PAGE_EXT_ESZ3		0x0080	/* ESZ3-bit: Size of page */

#define _PAGE_EXT_USER_EXEC	0x0100	/* EPR0-bit: User space executable */
#define _PAGE_EXT_USER_WRITE	0x0200	/* EPR1-bit: User space writable */
#define _PAGE_EXT_USER_READ	0x0400	/* EPR2-bit: User space readable */

#define _PAGE_EXT_KERN_EXEC	0x0800	/* EPR3-bit: Kernel space executable */
#define _PAGE_EXT_KERN_WRITE	0x1000	/* EPR4-bit: Kernel space writable */
#define _PAGE_EXT_KERN_READ	0x2000	/* EPR5-bit: Kernel space readable */

/* Wrapper for extended mode pgprot twiddling */
#define _PAGE_EXT(x)		((unsigned long long)(x) << 32)

/* software: moves to PTEA.TC (Timing Control) */
#define _PAGE_PCC_AREA5	0x00000000	/* use BSC registers for area5 */
#define _PAGE_PCC_AREA6	0x80000000	/* use BSC registers for area6 */

/* software: moves to PTEA.SA[2:0] (Space Attributes) */
#define _PAGE_PCC_IODYN 0x00000001	/* IO space, dynamically sized bus */
#define _PAGE_PCC_IO8	0x20000000	/* IO space, 8 bit bus */
#define _PAGE_PCC_IO16	0x20000001	/* IO space, 16 bit bus */
#define _PAGE_PCC_COM8	0x40000000	/* Common Memory space, 8 bit bus */
#define _PAGE_PCC_COM16	0x40000001	/* Common Memory space, 16 bit bus */
#define _PAGE_PCC_ATR8	0x60000000	/* Attribute Memory space, 8 bit bus */
#define _PAGE_PCC_ATR16	0x60000001	/* Attribute Memory space, 6 bit bus */

/* Mask which drops unused bits from the PTEL value */
#if defined(CONFIG_CPU_SH3)
#define _PAGE_CLEAR_FLAGS	(_PAGE_PROTNONE | _PAGE_ACCESSED| \
				 _PAGE_FILE	| _PAGE_SZ1	| \
				 _PAGE_HW_SHARED)
#elif defined(CONFIG_X2TLB)
/* Get rid of the legacy PR/SZ bits when using extended mode */
#define _PAGE_CLEAR_FLAGS	(_PAGE_PROTNONE | _PAGE_ACCESSED | \
				 _PAGE_FILE | _PAGE_PR_MASK | _PAGE_SZ_MASK)
#else
#define _PAGE_CLEAR_FLAGS	(_PAGE_PROTNONE | _PAGE_ACCESSED | _PAGE_FILE)
#endif

#define _PAGE_FLAGS_HARDWARE_MASK	(0x1fffffff & ~(_PAGE_CLEAR_FLAGS))

/* Hardware flags, page size encoding */
#if defined(CONFIG_X2TLB)
# if defined(CONFIG_PAGE_SIZE_4KB)
#  define _PAGE_FLAGS_HARD	_PAGE_EXT(_PAGE_EXT_ESZ0)
# elif defined(CONFIG_PAGE_SIZE_8KB)
#  define _PAGE_FLAGS_HARD	_PAGE_EXT(_PAGE_EXT_ESZ1)
# elif defined(CONFIG_PAGE_SIZE_64KB)
#  define _PAGE_FLAGS_HARD	_PAGE_EXT(_PAGE_EXT_ESZ2)
# endif
#else
# if defined(CONFIG_PAGE_SIZE_4KB)
#  define _PAGE_FLAGS_HARD	_PAGE_SZ0
# elif defined(CONFIG_PAGE_SIZE_64KB)
#  define _PAGE_FLAGS_HARD	_PAGE_SZ1
# endif
#endif

#if defined(CONFIG_X2TLB)
# if defined(CONFIG_HUGETLB_PAGE_SIZE_64K)
#  define _PAGE_SZHUGE	(_PAGE_EXT_ESZ2)
# elif defined(CONFIG_HUGETLB_PAGE_SIZE_256K)
#  define _PAGE_SZHUGE	(_PAGE_EXT_ESZ0 | _PAGE_EXT_ESZ2)
# elif defined(CONFIG_HUGETLB_PAGE_SIZE_1MB)
#  define _PAGE_SZHUGE	(_PAGE_EXT_ESZ0 | _PAGE_EXT_ESZ1 | _PAGE_EXT_ESZ2)
# elif defined(CONFIG_HUGETLB_PAGE_SIZE_4MB)
#  define _PAGE_SZHUGE	(_PAGE_EXT_ESZ3)
# elif defined(CONFIG_HUGETLB_PAGE_SIZE_64MB)
#  define _PAGE_SZHUGE	(_PAGE_EXT_ESZ2 | _PAGE_EXT_ESZ3)
# endif
#else
# if defined(CONFIG_HUGETLB_PAGE_SIZE_64K)
#  define _PAGE_SZHUGE	(_PAGE_SZ1)
# elif defined(CONFIG_HUGETLB_PAGE_SIZE_1MB)
#  define _PAGE_SZHUGE	(_PAGE_SZ0 | _PAGE_SZ1)
# endif
#endif

/*
 * Stub out _PAGE_SZHUGE if we don't have a good definition for it,
 * to make pte_mkhuge() happy.
 */
#ifndef _PAGE_SZHUGE
# define _PAGE_SZHUGE	(_PAGE_FLAGS_HARD)
#endif

#define _PAGE_CHG_MASK \
	(PTE_MASK | _PAGE_ACCESSED | _PAGE_CACHABLE | _PAGE_DIRTY)

#ifndef __ASSEMBLY__

#if defined(CONFIG_X2TLB) /* SH-X2 TLB */
#define PAGE_NONE	__pgprot(_PAGE_PROTNONE | _PAGE_CACHABLE | \
				 _PAGE_ACCESSED | _PAGE_FLAGS_HARD)

#define PAGE_SHARED	__pgprot(_PAGE_PRESENT | _PAGE_ACCESSED | \
				 _PAGE_CACHABLE | _PAGE_FLAGS_HARD | \
				 _PAGE_EXT(_PAGE_EXT_KERN_READ  | \
					   _PAGE_EXT_KERN_WRITE | \
					   _PAGE_EXT_USER_READ  | \
					   _PAGE_EXT_USER_WRITE))

#define PAGE_EXECREAD	__pgprot(_PAGE_PRESENT | _PAGE_ACCESSED | \
				 _PAGE_CACHABLE | _PAGE_FLAGS_HARD | \
				 _PAGE_EXT(_PAGE_EXT_KERN_EXEC | \
					   _PAGE_EXT_KERN_READ | \
					   _PAGE_EXT_USER_EXEC | \
					   _PAGE_EXT_USER_READ))

#define PAGE_COPY	PAGE_EXECREAD

#define PAGE_READONLY	__pgprot(_PAGE_PRESENT | _PAGE_ACCESSED | \
				 _PAGE_CACHABLE | _PAGE_FLAGS_HARD | \
				 _PAGE_EXT(_PAGE_EXT_KERN_READ | \
					   _PAGE_EXT_USER_READ))

#define PAGE_WRITEONLY	__pgprot(_PAGE_PRESENT | _PAGE_ACCESSED | \
				 _PAGE_CACHABLE | _PAGE_FLAGS_HARD | \
				 _PAGE_EXT(_PAGE_EXT_KERN_WRITE | \
					   _PAGE_EXT_USER_WRITE))

#define PAGE_RWX	__pgprot(_PAGE_PRESENT | _PAGE_ACCESSED | \
				 _PAGE_CACHABLE | _PAGE_FLAGS_HARD | \
				 _PAGE_EXT(_PAGE_EXT_KERN_WRITE | \
					   _PAGE_EXT_KERN_READ  | \
					   _PAGE_EXT_KERN_EXEC  | \
					   _PAGE_EXT_USER_WRITE | \
					   _PAGE_EXT_USER_READ  | \
					   _PAGE_EXT_USER_EXEC))

#define PAGE_KERNEL	__pgprot(_PAGE_PRESENT | _PAGE_CACHABLE | \
				 _PAGE_DIRTY | _PAGE_ACCESSED | \
				 _PAGE_HW_SHARED | _PAGE_FLAGS_HARD | \
				 _PAGE_EXT(_PAGE_EXT_KERN_READ | \
					   _PAGE_EXT_KERN_WRITE | \
					   _PAGE_EXT_KERN_EXEC))

#define PAGE_KERNEL_NOCACHE \
			__pgprot(_PAGE_PRESENT | _PAGE_DIRTY | \
				 _PAGE_ACCESSED | _PAGE_HW_SHARED | \
				 _PAGE_FLAGS_HARD | \
				 _PAGE_EXT(_PAGE_EXT_KERN_READ | \
					   _PAGE_EXT_KERN_WRITE | \
					   _PAGE_EXT_KERN_EXEC))

#define PAGE_KERNEL_RO	__pgprot(_PAGE_PRESENT | _PAGE_CACHABLE | \
				 _PAGE_DIRTY | _PAGE_ACCESSED | \
				 _PAGE_HW_SHARED | _PAGE_FLAGS_HARD | \
				 _PAGE_EXT(_PAGE_EXT_KERN_READ | \
					   _PAGE_EXT_KERN_EXEC))

#define PAGE_KERNEL_PCC(slot, type) \
			__pgprot(_PAGE_PRESENT | _PAGE_DIRTY | \
				 _PAGE_ACCESSED | _PAGE_FLAGS_HARD | \
				 _PAGE_EXT(_PAGE_EXT_KERN_READ | \
					   _PAGE_EXT_KERN_WRITE | \
					   _PAGE_EXT_KERN_EXEC) \
				 (slot ? _PAGE_PCC_AREA5 : _PAGE_PCC_AREA6) | \
				 (type))

#elif defined(CONFIG_MMU) /* SH-X TLB */
#define PAGE_NONE	__pgprot(_PAGE_PROTNONE | _PAGE_CACHABLE | \
				 _PAGE_ACCESSED | _PAGE_FLAGS_HARD)

#define PAGE_SHARED	__pgprot(_PAGE_PRESENT | _PAGE_RW | _PAGE_USER | \
				 _PAGE_CACHABLE | _PAGE_ACCESSED | \
				 _PAGE_FLAGS_HARD)

#define PAGE_COPY	__pgprot(_PAGE_PRESENT | _PAGE_USER | _PAGE_CACHABLE | \
				 _PAGE_ACCESSED | _PAGE_FLAGS_HARD)

#define PAGE_READONLY	__pgprot(_PAGE_PRESENT | _PAGE_USER | _PAGE_CACHABLE | \
				 _PAGE_ACCESSED | _PAGE_FLAGS_HARD)

#define PAGE_EXECREAD	PAGE_READONLY
#define PAGE_RWX	PAGE_SHARED
#define PAGE_WRITEONLY	PAGE_SHARED

#define PAGE_KERNEL	__pgprot(_PAGE_PRESENT | _PAGE_RW | _PAGE_CACHABLE | \
				 _PAGE_DIRTY | _PAGE_ACCESSED | \
				 _PAGE_HW_SHARED | _PAGE_FLAGS_HARD)

#define PAGE_KERNEL_NOCACHE \
			__pgprot(_PAGE_PRESENT | _PAGE_RW | _PAGE_DIRTY | \
				 _PAGE_ACCESSED | _PAGE_HW_SHARED | \
				 _PAGE_FLAGS_HARD)

#define PAGE_KERNEL_RO	__pgprot(_PAGE_PRESENT | _PAGE_CACHABLE | \
				 _PAGE_DIRTY | _PAGE_ACCESSED | \
				 _PAGE_HW_SHARED | _PAGE_FLAGS_HARD)

#define PAGE_KERNEL_PCC(slot, type) \
			__pgprot(_PAGE_PRESENT | _PAGE_RW | _PAGE_DIRTY | \
				 _PAGE_ACCESSED | _PAGE_FLAGS_HARD | \
				 (slot ? _PAGE_PCC_AREA5 : _PAGE_PCC_AREA6) | \
				 (type))
#else /* no mmu */
#define PAGE_NONE		__pgprot(0)
#define PAGE_SHARED		__pgprot(0)
#define PAGE_COPY		__pgprot(0)
#define PAGE_EXECREAD		__pgprot(0)
#define PAGE_RWX		__pgprot(0)
#define PAGE_READONLY		__pgprot(0)
#define PAGE_WRITEONLY		__pgprot(0)
#define PAGE_KERNEL		__pgprot(0)
#define PAGE_KERNEL_NOCACHE	__pgprot(0)
#define PAGE_KERNEL_RO		__pgprot(0)

#define PAGE_KERNEL_PCC(slot, type) \
				__pgprot(0)
#endif

#endif /* __ASSEMBLY__ */

/*
 * SH-X and lower (legacy) SuperH parts (SH-3, SH-4, some SH-4A) can't do page
 * protection for execute, and considers it the same as a read. Also, write
 * permission implies read permission. This is the closest we can get..
 *
 * SH-X2 (SH7785) and later parts take this to the opposite end of the extreme,
 * not only supporting separate execute, read, and write bits, but having
 * completely separate permission bits for user and kernel space.
 */
	 /*xwr*/
#define __P000	PAGE_NONE
#define __P001	PAGE_READONLY
#define __P010	PAGE_COPY
#define __P011	PAGE_COPY
#define __P100	PAGE_EXECREAD
#define __P101	PAGE_EXECREAD
#define __P110	PAGE_COPY
#define __P111	PAGE_COPY

#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

#ifndef __ASSEMBLY__

/*
 * Certain architectures need to do special things when PTEs
 * within a page table are directly modified.  Thus, the following
 * hook is made available.
 */
#ifdef CONFIG_X2TLB
static inline void set_pte(pte_t *ptep, pte_t pte)
{
	ptep->pte_high = pte.pte_high;
	smp_wmb();
	ptep->pte_low = pte.pte_low;
}
#else
#define set_pte(pteptr, pteval) (*(pteptr) = pteval)
#endif

#define set_pte_at(mm,addr,ptep,pteval) set_pte(ptep,pteval)

/*
 * (pmds are folded into pgds so this doesn't get actually called,
 * but the define is needed for a generic inline function.)
 */
#define set_pmd(pmdptr, pmdval) (*(pmdptr) = pmdval)

#define pte_pfn(x)		((unsigned long)(((x).pte_low >> PAGE_SHIFT)))

#define pfn_pte(pfn, prot) \
	__pte(((unsigned long long)(pfn) << PAGE_SHIFT) | pgprot_val(prot))
#define pfn_pmd(pfn, prot) \
	__pmd(((unsigned long long)(pfn) << PAGE_SHIFT) | pgprot_val(prot))

#define pte_none(x)		(!pte_val(x))
#define pte_present(x)		((x).pte_low & (_PAGE_PRESENT | _PAGE_PROTNONE))

#define pte_clear(mm,addr,xp) do { set_pte_at(mm, addr, xp, __pte(0)); } while (0)

#define pmd_none(x)	(!pmd_val(x))
#define pmd_present(x)	(pmd_val(x))
#define pmd_clear(xp)	do { set_pmd(xp, __pmd(0)); } while (0)
#define	pmd_bad(x)	(pmd_val(x) & ~PAGE_MASK)

#define pages_to_mb(x)	((x) >> (20-PAGE_SHIFT))
#define pte_page(x)	pfn_to_page(pte_pfn(x))

/*
 * The following only work if pte_present() is true.
 * Undefined behaviour if not..
 */
#define pte_not_present(pte)	(!((pte).pte_low & _PAGE_PRESENT))
#define pte_dirty(pte)		((pte).pte_low & _PAGE_DIRTY)
#define pte_young(pte)		((pte).pte_low & _PAGE_ACCESSED)
#define pte_file(pte)		((pte).pte_low & _PAGE_FILE)

#ifdef CONFIG_X2TLB
#define pte_write(pte)		((pte).pte_high & _PAGE_EXT_USER_WRITE)
#else
#define pte_write(pte)		((pte).pte_low & _PAGE_RW)
#endif

#define PTE_BIT_FUNC(h,fn,op) \
static inline pte_t pte_##fn(pte_t pte) { pte.pte_##h op; return pte; }

#ifdef CONFIG_X2TLB
/*
 * We cheat a bit in the SH-X2 TLB case. As the permission bits are
 * individually toggled (and user permissions are entirely decoupled from
 * kernel permissions), we attempt to couple them a bit more sanely here.
 */
PTE_BIT_FUNC(high, wrprotect, &= ~_PAGE_EXT_USER_WRITE);
PTE_BIT_FUNC(high, mkwrite, |= _PAGE_EXT_USER_WRITE | _PAGE_EXT_KERN_WRITE);
PTE_BIT_FUNC(high, mkhuge, |= _PAGE_SZHUGE);
#else
PTE_BIT_FUNC(low, wrprotect, &= ~_PAGE_RW);
PTE_BIT_FUNC(low, mkwrite, |= _PAGE_RW);
PTE_BIT_FUNC(low, mkhuge, |= _PAGE_SZHUGE);
#endif

PTE_BIT_FUNC(low, mkclean, &= ~_PAGE_DIRTY);
PTE_BIT_FUNC(low, mkdirty, |= _PAGE_DIRTY);
PTE_BIT_FUNC(low, mkold, &= ~_PAGE_ACCESSED);
PTE_BIT_FUNC(low, mkyoung, |= _PAGE_ACCESSED);

/*
 * Macro and implementation to make a page protection as uncachable.
 */
#define pgprot_writecombine(prot) \
	__pgprot(pgprot_val(prot) & ~_PAGE_CACHABLE)

#define pgprot_noncached	 pgprot_writecombine

/*
 * Conversion functions: convert a page and protection to a page entry,
 * and a page entry and page directory to the page they refer to.
 *
 * extern pte_t mk_pte(struct page *page, pgprot_t pgprot)
 */
#define mk_pte(page, pgprot)	pfn_pte(page_to_pfn(page), (pgprot))

static inline pte_t pte_modify(pte_t pte, pgprot_t newprot)
{
	pte.pte_low &= _PAGE_CHG_MASK;
	pte.pte_low |= pgprot_val(newprot);

#ifdef CONFIG_X2TLB
	pte.pte_high |= pgprot_val(newprot) >> 32;
#endif

	return pte;
}

#define pmd_page_vaddr(pmd)	((unsigned long)pmd_val(pmd))
#define pmd_page(pmd)		(virt_to_page(pmd_val(pmd)))

/* to find an entry in a page-table-directory. */
#define pgd_index(address)	(((address) >> PGDIR_SHIFT) & (PTRS_PER_PGD-1))
#define pgd_offset(mm, address)	((mm)->pgd+pgd_index(address))

/* 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 third-level page table.. */
#define pte_index(address)	((address >> PAGE_SHIFT) & (PTRS_PER_PTE - 1))
#define pte_offset_kernel(dir, address) \
	((pte_t *) pmd_page_vaddr(*(dir)) + pte_index(address))
#define pte_offset_map(dir, address)		pte_offset_kernel(dir, address)
#define pte_offset_map_nested(dir, address)	pte_offset_kernel(dir, address)

#define pte_unmap(pte)		do { } while (0)
#define pte_unmap_nested(pte)	do { } while (0)

#ifdef CONFIG_X2TLB
#define pte_ERROR(e) \
	printk("%s:%d: bad pte %p(%08lx%08lx).\n", __FILE__, __LINE__, \
	       &(e), (e).pte_high, (e).pte_low)
#define pgd_ERROR(e) \
	printk("%s:%d: bad pgd %016llx.\n", __FILE__, __LINE__, pgd_val(e))
#else
#define pte_ERROR(e) \
	printk("%s:%d: bad pte %08lx.\n", __FILE__, __LINE__, pte_val(e))
#define pgd_ERROR(e) \
	printk("%s:%d: bad pgd %08lx.\n", __FILE__, __LINE__, pgd_val(e))
#endif

struct vm_area_struct;
extern void update_mmu_cache(struct vm_area_struct * vma,
			     unsigned long address, pte_t pte);

/*
 * Encode and de-code a swap entry
 *
 * Constraints:
 *	_PAGE_FILE at bit 0
 *	_PAGE_PRESENT at bit 8
 *	_PAGE_PROTNONE at bit 9
 *
 * For the normal case, we encode the swap type into bits 0:7 and the
 * swap offset into bits 10:30. For the 64-bit PTE case, we keep the
 * preserved bits in the low 32-bits and use the upper 32 as the swap
 * offset (along with a 5-bit type), following the same approach as x86
 * PAE. This keeps the logic quite simple, and allows for a full 32
 * PTE_FILE_MAX_BITS, as opposed to the 29-bits we're constrained with
 * in the pte_low case.
 *
 * As is evident by the Alpha code, if we ever get a 64-bit unsigned
 * long (swp_entry_t) to match up with the 64-bit PTEs, this all becomes
 * much cleaner..
 *
 * NOTE: We should set ZEROs at the position of _PAGE_PRESENT
 *       and _PAGE_PROTNONE bits
 */
#ifdef CONFIG_X2TLB
#define __swp_type(x)			((x).val & 0x1f)
#define __swp_offset(x)			((x).val >> 5)
#define __swp_entry(type, offset)	((swp_entry_t){ (type) | (offset) << 5})
#define __pte_to_swp_entry(pte)		((swp_entry_t){ (pte).pte_high })
#define __swp_entry_to_pte(x)		((pte_t){ 0, (x).val })

/*
 * Encode and decode a nonlinear file mapping entry
 */
#define pte_to_pgoff(pte)		((pte).pte_high)
#define pgoff_to_pte(off)		((pte_t) { _PAGE_FILE, (off) })

#define PTE_FILE_MAX_BITS		32
#else
#define __swp_type(x)			((x).val & 0xff)
#define __swp_offset(x)			((x).val >> 10)
#define __swp_entry(type, offset)	((swp_entry_t){(type) | (offset) <<10})

#define __pte_to_swp_entry(pte)		((swp_entry_t) { pte_val(pte) >> 1 })
#define __swp_entry_to_pte(x)		((pte_t) { (x).val << 1 })

/*
 * Encode and decode a nonlinear file mapping entry
 */
#define PTE_FILE_MAX_BITS	29
#define pte_to_pgoff(pte)	(pte_val(pte) >> 1)
#define pgoff_to_pte(off)	((pte_t) { ((off) << 1) | _PAGE_FILE })
#endif

typedef pte_t *pte_addr_t;

#define kern_addr_valid(addr)	(1)

#define io_remap_pfn_range(vma, vaddr, pfn, size, prot)		\
		remap_pfn_range(vma, vaddr, pfn, size, prot)

struct mm_struct;

/*
 * No page table caches to initialise
 */
#define pgtable_cache_init()	do { } while (0)

#ifndef CONFIG_MMU
extern unsigned int kobjsize(const void *objp);
#endif /* !CONFIG_MMU */

#if !defined(CONFIG_CACHE_OFF) && (defined(CONFIG_CPU_SH4) || \
	defined(CONFIG_SH7705_CACHE_32KB))
#define __HAVE_ARCH_PTEP_GET_AND_CLEAR
extern pte_t ptep_get_and_clear(struct mm_struct *mm, unsigned long addr, pte_t *ptep);
#endif

extern pgd_t swapper_pg_dir[PTRS_PER_PGD];
extern void paging_init(void);

#include <asm-generic/pgtable.h>

#endif /* !__ASSEMBLY__ */
#endif /* __ASM_SH_PAGE_H */