pgtable.h

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/*
 * 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__ */

/*
 * 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 | \