LXR linux/include/asm-mips/pgtable-64.h

   1/*
   2 * This file is subject to the terms and conditions of the GNU General Public
   3 * License.  See the file "COPYING" in the main directory of this archive
   4 * for more details.
   5 *
   6 * Copyright (C) 1994, 95, 96, 97, 98, 99, 2000, 2003 Ralf Baechle
   7 * Copyright (C) 1999, 2000, 2001 Silicon Graphics, Inc.
   8 */
   9#ifndef _ASM_PGTABLE_64_H
  10#define _ASM_PGTABLE_64_H
  11
  12#include <linux/config.h>
  13#include <linux/linkage.h>
  14
  15#include <asm/addrspace.h>
  16#include <asm/page.h>
  17#include <asm/cachectl.h>
  18
  19/*
  20 * Each address space has 2 4K pages as its page directory, giving 1024
  21 * (== PTRS_PER_PGD) 8 byte pointers to pmd tables. Each pmd table is a
  22 * pair of 4K pages, giving 1024 (== PTRS_PER_PMD) 8 byte pointers to
  23 * page tables. Each page table is a single 4K page, giving 512 (==
  24 * PTRS_PER_PTE) 8 byte ptes. Each pgde is initialized to point to
  25 * invalid_pmd_table, each pmde is initialized to point to
  26 * invalid_pte_table, each pte is initialized to 0. When memory is low,
  27 * and a pmd table or a page table allocation fails, empty_bad_pmd_table
  28 * and empty_bad_page_table is returned back to higher layer code, so
  29 * that the failure is recognized later on. Linux does not seem to
  30 * handle these failures very well though. The empty_bad_page_table has
  31 * invalid pte entries in it, to force page faults.
  32 *
  33 * Kernel mappings: kernel mappings are held in the swapper_pg_table.
  34 * The layout is identical to userspace except it's indexed with the
  35 * fault address - VMALLOC_START.
  36 */
  37
  38/* PMD_SHIFT determines the size of the area a second-level page table can map */
  39#define PMD_SHIFT       (PAGE_SHIFT + (PAGE_SHIFT - 3))
  40#define PMD_SIZE        (1UL << PMD_SHIFT)
  41#define PMD_MASK        (~(PMD_SIZE-1))
  42
  43/* PGDIR_SHIFT determines what a third-level page table entry can map */
  44#define PGDIR_SHIFT     (PMD_SHIFT + (PAGE_SHIFT + 1 - 3))
  45#define PGDIR_SIZE      (1UL << PGDIR_SHIFT)
  46#define PGDIR_MASK      (~(PGDIR_SIZE-1))
  47
  48/*
  49 * For 4kB page size we use a 3 level page tree and a 8kB pmd and pgds which
  50 * permits us mapping 40 bits of virtual address space.
  51 *
  52 * We used to implement 41 bits by having an order 1 pmd level but that seemed
  53 * rather pointless.
  54 *
  55 * For 8kB page size we use a 3 level page tree which permits a total of
  56 * 8TB of address space.  Alternatively a 33-bit / 8GB organization using
  57 * two levels would be easy to implement.
  58 *
  59 * For 16kB page size we use a 2 level page tree which permits a total of
  60 * 36 bits of virtual address space.  We could add a third leve. but it seems
  61 * like at the moment there's no need for this.
  62 *
  63 * For 64kB page size we use a 2 level page table tree for a total of 42 bits
  64 * of virtual address space.
  65 */
  66#ifdef CONFIG_PAGE_SIZE_4KB
  67#define PGD_ORDER               1
  68#define PMD_ORDER               0
  69#define PTE_ORDER               0
  70#endif
  71#ifdef CONFIG_PAGE_SIZE_8KB
  72#define PGD_ORDER               0
  73#define PMD_ORDER               0
  74#define PTE_ORDER               0
  75#endif
  76#ifdef CONFIG_PAGE_SIZE_16KB
  77#define PGD_ORDER               0
  78#define PMD_ORDER               0
  79#define PTE_ORDER               0
  80#endif
  81#ifdef CONFIG_PAGE_SIZE_64KB
  82#define PGD_ORDER               0
  83#define PMD_ORDER               0
  84#define PTE_ORDER               0
  85#endif
  86
  87#define PTRS_PER_PGD    ((PAGE_SIZE << PGD_ORDER) / sizeof(pgd_t))
  88#define PTRS_PER_PMD    ((PAGE_SIZE << PMD_ORDER) / sizeof(pmd_t))
  89#define PTRS_PER_PTE    ((PAGE_SIZE << PTE_ORDER) / sizeof(pte_t))
  90
  91#define USER_PTRS_PER_PGD       (TASK_SIZE / PGDIR_SIZE)
  92#define FIRST_USER_PGD_NR       0
  93
  94#define VMALLOC_START           XKSEG
  95#define VMALLOC_END     \
  96        (VMALLOC_START + PTRS_PER_PGD * PTRS_PER_PMD * PTRS_PER_PTE * PAGE_SIZE)
  97
  98#define pte_ERROR(e) \
  99        printk("%s:%d: bad pte %016lx.\n", __FILE__, __LINE__, pte_val(e))
 100#define pmd_ERROR(e) \
 101        printk("%s:%d: bad pmd %016lx.\n", __FILE__, __LINE__, pmd_val(e))
 102#define pgd_ERROR(e) \
 103        printk("%s:%d: bad pgd %016lx.\n", __FILE__, __LINE__, pgd_val(e))
 104
 105extern pte_t invalid_pte_table[PAGE_SIZE/sizeof(pte_t)];
 106extern pte_t empty_bad_page_table[PAGE_SIZE/sizeof(pte_t)];
 107extern pmd_t invalid_pmd_table[2*PAGE_SIZE/sizeof(pmd_t)];
 108extern pmd_t empty_bad_pmd_table[2*PAGE_SIZE/sizeof(pmd_t)];
 109
 110/*
 111 * Empty pmd entries point to the invalid_pte_table.
 112 */
 113static inline int pmd_none(pmd_t pmd)
 114{
 115        return pmd_val(pmd) == (unsigned long) invalid_pte_table;
 116}
 117
 118#define pmd_bad(pmd)            (pmd_val(pmd) & ~PAGE_MASK)
 119
 120static inline int pmd_present(pmd_t pmd)
 121{
 122        return pmd_val(pmd) != (unsigned long) invalid_pte_table;
 123}
 124
 125static inline void pmd_clear(pmd_t *pmdp)
 126{
 127        pmd_val(*pmdp) = ((unsigned long) invalid_pte_table);
 128}
 129
 130/*
 131 * Empty pgd entries point to the invalid_pmd_table.
 132 */
 133static inline int pgd_none(pgd_t pgd)
 134{
 135        return pgd_val(pgd) == (unsigned long) invalid_pmd_table;
 136}
 137
 138#define pgd_bad(pgd)            (pgd_val(pgd) &~ PAGE_MASK)
 139
 140static inline int pgd_present(pgd_t pgd)
 141{
 142        return pgd_val(pgd) != (unsigned long) invalid_pmd_table;
 143}
 144
 145static inline void pgd_clear(pgd_t *pgdp)
 146{
 147        pgd_val(*pgdp) = ((unsigned long) invalid_pmd_table);
 148}
 149
 150#define pte_page(x)             pfn_to_page((unsigned long)((pte_val(x) >> PAGE_SHIFT)))
 151#ifdef CONFIG_CPU_VR41XX
 152#define pte_pfn(x)              ((unsigned long)((x).pte >> (PAGE_SHIFT + 2)))
 153#define pfn_pte(pfn, prot)      __pte(((pfn) << (PAGE_SHIFT + 2)) | pgprot_val(prot))
 154#else
 155#define pte_pfn(x)              ((unsigned long)((x).pte >> PAGE_SHIFT))
 156#define pfn_pte(pfn, prot)      __pte(((pfn) << PAGE_SHIFT) | pgprot_val(prot))
 157#endif
 158
 159#define __pgd_offset(address)   pgd_index(address)
 160#define page_pte(page) page_pte_prot(page, __pgprot(0))
 161
 162/* to find an entry in a kernel page-table-directory */
 163#define pgd_offset_k(address) pgd_offset(&init_mm, 0)
 164
 165#define pgd_index(address)              ((address) >> PGDIR_SHIFT)
 166
 167/* to find an entry in a page-table-directory */
 168#define pgd_offset(mm,addr)     ((mm)->pgd + pgd_index(addr))
 169
 170static inline unsigned long pgd_page(pgd_t pgd)
 171{
 172        return pgd_val(pgd);
 173}
 174
 175/* Find an entry in the second-level page table.. */
 176static inline pmd_t *pmd_offset(pgd_t * dir, unsigned long address)
 177{
 178        return (pmd_t *) pgd_page(*dir) +
 179               ((address >> PMD_SHIFT) & (PTRS_PER_PMD - 1));
 180}
 181
 182/* Find an entry in the third-level page table.. */
 183#define __pte_offset(address)                                           \
 184        (((address) >> PAGE_SHIFT) & (PTRS_PER_PTE - 1))
 185#define pte_offset(dir, address)                                        \
 186        ((pte_t *) (pmd_page_kernel(*dir)) + __pte_offset(address))
 187#define pte_offset_kernel(dir, address)                                 \
 188        ((pte_t *) pmd_page_kernel(*(dir)) +  __pte_offset(address))
 189#define pte_offset_map(dir, address)                                    \
 190        ((pte_t *)page_address(pmd_page(*(dir))) + __pte_offset(address))
 191#define pte_offset_map_nested(dir, address)                             \
 192        ((pte_t *)page_address(pmd_page(*(dir))) + __pte_offset(address))
 193#define pte_unmap(pte) ((void)(pte))
 194#define pte_unmap_nested(pte) ((void)(pte))
 195
 196/*
 197 * Initialize a new pgd / pmd table with invalid pointers.
 198 */
 199extern void pgd_init(unsigned long page);
 200extern void pmd_init(unsigned long page, unsigned long pagetable);
 201
 202/*
 203 * Non-present pages:  high 24 bits are offset, next 8 bits type,
 204 * low 32 bits zero.
 205 */
 206static inline pte_t mk_swap_pte(unsigned long type, unsigned long offset)
 207{ pte_t pte; pte_val(pte) = (type << 32) | (offset << 40); return pte; }
 208
 209#define __swp_type(x)           (((x).val >> 32) & 0xff)
 210#define __swp_offset(x)         ((x).val >> 40)
 211#define __swp_entry(type,offset) ((swp_entry_t) { pte_val(mk_swap_pte((type),(offset))) })
 212#define __pte_to_swp_entry(pte) ((swp_entry_t) { pte_val(pte) })
 213#define __swp_entry_to_pte(x)   ((pte_t) { (x).val })
 214
 215/*
 216 * Bits 0, 1, 2, 7 and 8 are taken, split up the 32 bits of offset
 217 * into this range:
 218 */
 219#define PTE_FILE_MAX_BITS       32
 220
 221#define pte_to_pgoff(_pte) \
 222        ((((_pte).pte >> 3) & 0x1f ) + (((_pte).pte >> 9) << 6 ))
 223
 224#define pgoff_to_pte(off) \
 225        ((pte_t) { (((off) & 0x1f) << 3) + (((off) >> 6) << 9) + _PAGE_FILE })
 226
 227#endif /* _ASM_PGTABLE_64_H */
 228