LXR linux/arch/avr32/include/asm/pgtable.h

   1/*
   2 * Copyright (C) 2004-2006 Atmel Corporation
   3 *
   4 * This program is free software; you can redistribute it and/or modify
   5 * it under the terms of the GNU General Public License version 2 as
   6 * published by the Free Software Foundation.
   7 */
   8#ifndef __ASM_AVR32_PGTABLE_H
   9#define __ASM_AVR32_PGTABLE_H
  10
  11#include <asm/addrspace.h>
  12
  13#ifndef __ASSEMBLY__
  14#include <linux/sched.h>
  15
  16#endif /* !__ASSEMBLY__ */
  17
  18/*
  19 * Use two-level page tables just as the i386 (without PAE)
  20 */
  21#include <asm/pgtable-2level.h>
  22
  23/*
  24 * The following code might need some cleanup when the values are
  25 * final...
  26 */
  27#define PMD_SIZE        (1UL << PMD_SHIFT)
  28#define PMD_MASK        (~(PMD_SIZE-1))
  29#define PGDIR_SIZE      (1UL << PGDIR_SHIFT)
  30#define PGDIR_MASK      (~(PGDIR_SIZE-1))
  31
  32#define USER_PTRS_PER_PGD       (TASK_SIZE / PGDIR_SIZE)
  33#define FIRST_USER_ADDRESS      0
  34
  35#ifndef __ASSEMBLY__
  36extern pgd_t swapper_pg_dir[PTRS_PER_PGD];
  37extern void paging_init(void);
  38
  39/*
  40 * ZERO_PAGE is a global shared page that is always zero: used for
  41 * zero-mapped memory areas etc.
  42 */
  43extern struct page *empty_zero_page;
  44#define ZERO_PAGE(vaddr) (empty_zero_page)
  45
  46/*
  47 * Just any arbitrary offset to the start of the vmalloc VM area: the
  48 * current 8 MiB value just means that there will be a 8 MiB "hole"
  49 * after the uncached physical memory (P2 segment) until the vmalloc
  50 * area starts. That means that any out-of-bounds memory accesses will
  51 * hopefully be caught; we don't know if the end of the P1/P2 segments
  52 * are actually used for anything, but it is anyway safer to let the
  53 * MMU catch these kinds of errors than to rely on the memory bus.
  54 *
  55 * A "hole" of the same size is added to the end of the P3 segment as
  56 * well. It might seem wasteful to use 16 MiB of virtual address space
  57 * on this, but we do have 512 MiB of it...
  58 *
  59 * The vmalloc() routines leave a hole of 4 KiB between each vmalloced
  60 * area for the same reason.
  61 */
  62#define VMALLOC_OFFSET  (8 * 1024 * 1024)
  63#define VMALLOC_START   (P3SEG + VMALLOC_OFFSET)
  64#define VMALLOC_END     (P4SEG - VMALLOC_OFFSET)
  65#endif /* !__ASSEMBLY__ */
  66
  67/*
  68 * Page flags. Some of these flags are not directly supported by
  69 * hardware, so we have to emulate them.
  70 */
  71#define _TLBEHI_BIT_VALID       9
  72#define _TLBEHI_VALID           (1 << _TLBEHI_BIT_VALID)
  73
  74#define _PAGE_BIT_WT            0  /* W-bit   : write-through */
  75#define _PAGE_BIT_DIRTY         1  /* D-bit   : page changed */
  76#define _PAGE_BIT_SZ0           2  /* SZ0-bit : Size of page */
  77#define _PAGE_BIT_SZ1           3  /* SZ1-bit : Size of page */
  78#define _PAGE_BIT_EXECUTE       4  /* X-bit   : execute access allowed */
  79#define _PAGE_BIT_RW            5  /* AP0-bit : write access allowed */
  80#define _PAGE_BIT_USER          6  /* AP1-bit : user space access allowed */
  81#define _PAGE_BIT_BUFFER        7  /* B-bit   : bufferable */
  82#define _PAGE_BIT_GLOBAL        8  /* G-bit   : global (ignore ASID) */
  83#define _PAGE_BIT_CACHABLE      9  /* C-bit   : cachable */
  84
  85/* If we drop support for 1K pages, we get two extra bits */
  86#define _PAGE_BIT_PRESENT       10
  87#define _PAGE_BIT_ACCESSED      11 /* software: page was accessed */
  88
  89/* The following flags are only valid when !PRESENT */
  90#define _PAGE_BIT_FILE          0 /* software: pagecache or swap? */
  91
  92#define _PAGE_WT                (1 << _PAGE_BIT_WT)
  93#define _PAGE_DIRTY             (1 << _PAGE_BIT_DIRTY)
  94#define _PAGE_EXECUTE           (1 << _PAGE_BIT_EXECUTE)
  95#define _PAGE_RW                (1 << _PAGE_BIT_RW)
  96#define _PAGE_USER              (1 << _PAGE_BIT_USER)
  97#define _PAGE_BUFFER            (1 << _PAGE_BIT_BUFFER)
  98#define _PAGE_GLOBAL            (1 << _PAGE_BIT_GLOBAL)
  99#define _PAGE_CACHABLE          (1 << _PAGE_BIT_CACHABLE)
 100
 101/* Software flags */
 102#define _PAGE_ACCESSED          (1 << _PAGE_BIT_ACCESSED)
 103#define _PAGE_PRESENT           (1 << _PAGE_BIT_PRESENT)
 104#define _PAGE_FILE              (1 << _PAGE_BIT_FILE)
 105
 106/*
 107 * Page types, i.e. sizes. _PAGE_TYPE_NONE corresponds to what is
 108 * usually called _PAGE_PROTNONE on other architectures.
 109 *
 110 * XXX: Find out if _PAGE_PROTNONE is equivalent with !_PAGE_USER. If
 111 * so, we can encode all possible page sizes (although we can't really
 112 * support 1K pages anyway due to the _PAGE_PRESENT and _PAGE_ACCESSED
 113 * bits)
 114 *
 115 */
 116#define _PAGE_TYPE_MASK         ((1 << _PAGE_BIT_SZ0) | (1 << _PAGE_BIT_SZ1))
 117#define _PAGE_TYPE_NONE         (0 << _PAGE_BIT_SZ0)
 118#define _PAGE_TYPE_SMALL        (1 << _PAGE_BIT_SZ0)
 119#define _PAGE_TYPE_MEDIUM       (2 << _PAGE_BIT_SZ0)
 120#define _PAGE_TYPE_LARGE        (3 << _PAGE_BIT_SZ0)
 121
 122/*
 123 * Mask which drop software flags. We currently can't handle more than
 124 * 512 MiB of physical memory, so we can use bits 29-31 for other
 125 * stuff.  With a fixed 4K page size, we can use bits 10-11 as well as
 126 * bits 2-3 (SZ)
 127 */
 128#define _PAGE_FLAGS_HARDWARE_MASK       0xfffff3ff
 129
 130#define _PAGE_FLAGS_CACHE_MASK  (_PAGE_CACHABLE | _PAGE_BUFFER | _PAGE_WT)
 131
 132/* Flags that may be modified by software */
 133#define _PAGE_CHG_MASK          (PTE_MASK | _PAGE_ACCESSED | _PAGE_DIRTY \
 134                                 | _PAGE_FLAGS_CACHE_MASK)
 135
 136#define _PAGE_FLAGS_READ        (_PAGE_CACHABLE | _PAGE_BUFFER)
 137#define _PAGE_FLAGS_WRITE       (_PAGE_FLAGS_READ | _PAGE_RW | _PAGE_DIRTY)
 138
 139#define _PAGE_NORMAL(x) __pgprot((x) | _PAGE_PRESENT | _PAGE_TYPE_SMALL \
 140                                 | _PAGE_ACCESSED)
 141
 142#define PAGE_NONE       (_PAGE_ACCESSED | _PAGE_TYPE_NONE)
 143#define PAGE_READ       (_PAGE_FLAGS_READ | _PAGE_USER)
 144#define PAGE_EXEC       (_PAGE_FLAGS_READ | _PAGE_EXECUTE | _PAGE_USER)
 145#define PAGE_WRITE      (_PAGE_FLAGS_WRITE | _PAGE_USER)
 146#define PAGE_KERNEL     _PAGE_NORMAL(_PAGE_FLAGS_WRITE | _PAGE_EXECUTE | _PAGE_GLOBAL)
 147#define PAGE_KERNEL_RO  _PAGE_NORMAL(_PAGE_FLAGS_READ | _PAGE_EXECUTE | _PAGE_GLOBAL)
 148
 149#define _PAGE_P(x)      _PAGE_NORMAL((x) & ~(_PAGE_RW | _PAGE_DIRTY))
 150#define _PAGE_S(x)      _PAGE_NORMAL(x)
 151
 152#define PAGE_COPY       _PAGE_P(PAGE_WRITE | PAGE_READ)
 153#define PAGE_SHARED     _PAGE_S(PAGE_WRITE | PAGE_READ)
 154
 155#ifndef __ASSEMBLY__
 156/*
 157 * The hardware supports flags for write- and execute access. Read is
 158 * always allowed if the page is loaded into the TLB, so the "-w-",
 159 * "--x" and "-wx" mappings are implemented as "rw-", "r-x" and "rwx",
 160 * respectively.
 161 *
 162 * The "---" case is handled by software; the page will simply not be
 163 * loaded into the TLB if the page type is _PAGE_TYPE_NONE.
 164 */
 165
 166#define __P000  __pgprot(PAGE_NONE)
 167#define __P001  _PAGE_P(PAGE_READ)
 168#define __P010  _PAGE_P(PAGE_WRITE)
 169#define __P011  _PAGE_P(PAGE_WRITE | PAGE_READ)
 170#define __P100  _PAGE_P(PAGE_EXEC)
 171#define __P101  _PAGE_P(PAGE_EXEC | PAGE_READ)
 172#define __P110  _PAGE_P(PAGE_EXEC | PAGE_WRITE)
 173#define __P111  _PAGE_P(PAGE_EXEC | PAGE_WRITE | PAGE_READ)
 174
 175#define __S000  __pgprot(PAGE_NONE)
 176#define __S001  _PAGE_S(PAGE_READ)
 177#define __S010  _PAGE_S(PAGE_WRITE)
 178#define __S011  _PAGE_S(PAGE_WRITE | PAGE_READ)
 179#define __S100  _PAGE_S(PAGE_EXEC)
 180#define __S101  _PAGE_S(PAGE_EXEC | PAGE_READ)
 181#define __S110  _PAGE_S(PAGE_EXEC | PAGE_WRITE)
 182#define __S111  _PAGE_S(PAGE_EXEC | PAGE_WRITE | PAGE_READ)
 183
 184#define pte_none(x)     (!pte_val(x))
 185#define pte_present(x)  (pte_val(x) & _PAGE_PRESENT)
 186
 187#define pte_clear(mm,addr,xp)                                   \
 188        do {                                                    \
 189                set_pte_at(mm, addr, xp, __pte(0));             \
 190        } while (0)
 191
 192/*
 193 * The following only work if pte_present() is true.
 194 * Undefined behaviour if not..
 195 */
 196static inline int pte_write(pte_t pte)
 197{
 198        return pte_val(pte) & _PAGE_RW;
 199}
 200static inline int pte_dirty(pte_t pte)
 201{
 202        return pte_val(pte) & _PAGE_DIRTY;
 203}
 204static inline int pte_young(pte_t pte)
 205{
 206        return pte_val(pte) & _PAGE_ACCESSED;
 207}
 208static inline int pte_special(pte_t pte)
 209{
 210        return 0;
 211}
 212
 213/*
 214 * The following only work if pte_present() is not true.
 215 */
 216static inline int pte_file(pte_t pte)
 217{
 218        return pte_val(pte) & _PAGE_FILE;
 219}
 220
 221/* Mutator functions for PTE bits */
 222static inline pte_t pte_wrprotect(pte_t pte)
 223{
 224        set_pte(&pte, __pte(pte_val(pte) & ~_PAGE_RW));
 225        return pte;
 226}
 227static inline pte_t pte_mkclean(pte_t pte)
 228{
 229        set_pte(&pte, __pte(pte_val(pte) & ~_PAGE_DIRTY));
 230        return pte;
 231}
 232static inline pte_t pte_mkold(pte_t pte)
 233{
 234        set_pte(&pte, __pte(pte_val(pte) & ~_PAGE_ACCESSED));
 235        return pte;
 236}
 237static inline pte_t pte_mkwrite(pte_t pte)
 238{
 239        set_pte(&pte, __pte(pte_val(pte) | _PAGE_RW));
 240        return pte;
 241}
 242static inline pte_t pte_mkdirty(pte_t pte)
 243{
 244        set_pte(&pte, __pte(pte_val(pte) | _PAGE_DIRTY));
 245        return pte;
 246}
 247static inline pte_t pte_mkyoung(pte_t pte)
 248{
 249        set_pte(&pte, __pte(pte_val(pte) | _PAGE_ACCESSED));
 250        return pte;
 251}
 252static inline pte_t pte_mkspecial(pte_t pte)
 253{
 254        return pte;
 255}
 256
 257#define pmd_none(x)     (!pmd_val(x))
 258#define pmd_present(x)  (pmd_val(x))
 259
 260static inline void pmd_clear(pmd_t *pmdp)
 261{
 262        set_pmd(pmdp, __pmd(0));
 263}
 264
 265#define pmd_bad(x)      (pmd_val(x) & ~PAGE_MASK)
 266
 267/*
 268 * Permanent address of a page. We don't support highmem, so this is
 269 * trivial.
 270 */
 271#define pages_to_mb(x)  ((x) >> (20-PAGE_SHIFT))
 272#define pte_page(x)     (pfn_to_page(pte_pfn(x)))
 273
 274/*
 275 * Mark the prot value as uncacheable and unbufferable
 276 */
 277#define pgprot_noncached(prot)                                          \
 278        __pgprot(pgprot_val(prot) & ~(_PAGE_BUFFER | _PAGE_CACHABLE))
 279
 280/*
 281 * Mark the prot value as uncacheable but bufferable
 282 */
 283#define pgprot_writecombine(prot)                                       \
 284        __pgprot((pgprot_val(prot) & ~_PAGE_CACHABLE) | _PAGE_BUFFER)
 285
 286/*
 287 * Conversion functions: convert a page and protection to a page entry,
 288 * and a page entry and page directory to the page they refer to.
 289 *
 290 * extern pte_t mk_pte(struct page *page, pgprot_t pgprot)
 291 */
 292#define mk_pte(page, pgprot)    pfn_pte(page_to_pfn(page), (pgprot))
 293
 294static inline pte_t pte_modify(pte_t pte, pgprot_t newprot)
 295{
 296        set_pte(&pte, __pte((pte_val(pte) & _PAGE_CHG_MASK)
 297                            | pgprot_val(newprot)));
 298        return pte;
 299}
 300
 301#define page_pte(page)  page_pte_prot(page, __pgprot(0))
 302
 303#define pmd_page_vaddr(pmd)     pmd_val(pmd)
 304#define pmd_page(pmd)           (virt_to_page(pmd_val(pmd)))
 305
 306/* to find an entry in a page-table-directory. */
 307#define pgd_index(address)      (((address) >> PGDIR_SHIFT)     \
 308                                 & (PTRS_PER_PGD - 1))
 309#define pgd_offset(mm, address) ((mm)->pgd + pgd_index(address))
 310
 311/* to find an entry in a kernel page-table-directory */
 312#define pgd_offset_k(address)   pgd_offset(&init_mm, address)
 313
 314/* Find an entry in the third-level page table.. */
 315#define pte_index(address)                              \
 316        ((address >> PAGE_SHIFT) & (PTRS_PER_PTE - 1))
 317#define pte_offset(dir, address)                                        \
 318        ((pte_t *) pmd_page_vaddr(*(dir)) + pte_index(address))
 319#define pte_offset_kernel(dir, address)                                 \
 320        ((pte_t *) pmd_page_vaddr(*(dir)) + pte_index(address))
 321#define pte_offset_map(dir, address) pte_offset_kernel(dir, address)
 322#define pte_unmap(pte)          do { } while (0)
 323
 324struct vm_area_struct;
 325extern void update_mmu_cache(struct vm_area_struct * vma,
 326                             unsigned long address, pte_t *ptep);
 327
 328/*
 329 * Encode and decode a swap entry
 330 *
 331 * Constraints:
 332 *   _PAGE_FILE at bit 0
 333 *   _PAGE_TYPE_* at bits 2-3 (for emulating _PAGE_PROTNONE)
 334 *   _PAGE_PRESENT at bit 10
 335 *
 336 * We encode the type into bits 4-9 and offset into bits 11-31. This
 337 * gives us a 21 bits offset, or 2**21 * 4K = 8G usable swap space per
 338 * device, and 64 possible types.
 339 *
 340 * NOTE: We should set ZEROs at the position of _PAGE_PRESENT
 341 *       and _PAGE_PROTNONE bits
 342 */
 343#define __swp_type(x)           (((x).val >> 4) & 0x3f)
 344#define __swp_offset(x)         ((x).val >> 11)
 345#define __swp_entry(type, offset) ((swp_entry_t) { ((type) << 4) | ((offset) << 11) })
 346#define __pte_to_swp_entry(pte) ((swp_entry_t) { pte_val(pte) })
 347#define __swp_entry_to_pte(x)   ((pte_t) { (x).val })
 348
 349/*
 350 * Encode and decode a nonlinear file mapping entry. We have to
 351 * preserve _PAGE_FILE and _PAGE_PRESENT here. _PAGE_TYPE_* isn't
 352 * necessary, since _PAGE_FILE implies !_PAGE_PROTNONE (?)
 353 */
 354#define PTE_FILE_MAX_BITS       30
 355#define pte_to_pgoff(pte)       (((pte_val(pte) >> 1) & 0x1ff)          \
 356                                 | ((pte_val(pte) >> 11) << 9))
 357#define pgoff_to_pte(off)       ((pte_t) { ((((off) & 0x1ff) << 1)      \
 358                                            | (((off) >> 9) << 11)      \
 359                                            | _PAGE_FILE) })
 360
 361typedef pte_t *pte_addr_t;
 362
 363#define kern_addr_valid(addr)   (1)
 364
 365/* No page table caches to initialize (?) */
 366#define pgtable_cache_init()    do { } while(0)
 367
 368#include <asm-generic/pgtable.h>
 369
 370#endif /* !__ASSEMBLY__ */
 371
 372#endif /* __ASM_AVR32_PGTABLE_H */
 373