arch/arm/include/asm/pgtable.h

   1 /*
   2  *  arch/arm/include/asm/pgtable.h
   3  *
   4  *  Copyright (C) 1995-2002 Russell King
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License version 2 as
   8  * published by the Free Software Foundation.
   9  */
  10 #ifndef _ASMARM_PGTABLE_H
  11 #define _ASMARM_PGTABLE_H
  12
  13 #include <linux/const.h>
  14 #include <asm-generic/4level-fixup.h>
  15 #include <asm/proc-fns.h>
  16
  17 #ifndef CONFIG_MMU
  18
  19 #include "pgtable-nommu.h"
  20
  21 #else
  22
  23 #include <asm/memory.h>
  24 #include <mach/vmalloc.h>
  25 #include <asm/pgtable-hwdef.h>
  26
  27 /*
  28  * Just any arbitrary offset to the start of the vmalloc VM area: the
  29  * current 8MB value just means that there will be a 8MB "hole" after the
  30  * physical memory until the kernel virtual memory starts.  That means that
  31  * any out-of-bounds memory accesses will hopefully be caught.
  32  * The vmalloc() routines leaves a hole of 4kB between each vmalloced
  33  * area for the same reason. ;)
  34  *
  35  * Note that platforms may override VMALLOC_START, but they must provide
  36  * VMALLOC_END.  VMALLOC_END defines the (exclusive) limit of this space,
  37  * which may not overlap IO space.
  38  */
  39 #ifndef VMALLOC_START
  40 #define VMALLOC_OFFSET          (8*1024*1024)
  41 #define VMALLOC_START           (((unsigned long)high_memory + VMALLOC_OFFSET) & ~(VMALLOC_OFFSET-1))
  42 #endif
  43
  44 /*
  45  * Hardware-wise, we have a two level page table structure, where the first
  46  * level has 4096 entries, and the second level has 256 entries.  Each entry
  47  * is one 32-bit word.  Most of the bits in the second level entry are used
  48  * by hardware, and there aren't any "accessed" and "dirty" bits.
  49  *
  50  * Linux on the other hand has a three level page table structure, which can
  51  * be wrapped to fit a two level page table structure easily - using the PGD
  52  * and PTE only.  However, Linux also expects one "PTE" table per page, and
  53  * at least a "dirty" bit.
  54  *
  55  * Therefore, we tweak the implementation slightly - we tell Linux that we
  56  * have 2048 entries in the first level, each of which is 8 bytes (iow, two
  57  * hardware pointers to the second level.)  The second level contains two
  58  * hardware PTE tables arranged contiguously, preceded by Linux versions
  59  * which contain the state information Linux needs.  We, therefore, end up
  60  * with 512 entries in the "PTE" level.
  61  *
  62  * This leads to the page tables having the following layout:
  63  *
  64  *    pgd             pte
  65  * |        |
  66  * +--------+
  67  * |        |       +------------+ +0
  68  * +- - - - +       | Linux pt 0 |
  69  * |        |       +------------+ +1024
  70  * +--------+ +0    | Linux pt 1 |
  71  * |        |-----> +------------+ +2048
  72  * +- - - - + +4    |  h/w pt 0  |
  73  * |        |-----> +------------+ +3072
  74  * +--------+ +8    |  h/w pt 1  |
  75  * |        |       +------------+ +4096
  76  *
  77  * See L_PTE_xxx below for definitions of bits in the "Linux pt", and
  78  * PTE_xxx for definitions of bits appearing in the "h/w pt".
  79  *
  80  * PMD_xxx definitions refer to bits in the first level page table.
  81  *
  82  * The "dirty" bit is emulated by only granting hardware write permission
  83  * iff the page is marked "writable" and "dirty" in the Linux PTE.  This
  84  * means that a write to a clean page will cause a permission fault, and
  85  * the Linux MM layer will mark the page dirty via handle_pte_fault().
  86  * For the hardware to notice the permission change, the TLB entry must
  87  * be flushed, and ptep_set_access_flags() does that for us.
  88  *
  89  * The "accessed" or "young" bit is emulated by a similar method; we only
  90  * allow accesses to the page if the "young" bit is set.  Accesses to the
  91  * page will cause a fault, and handle_pte_fault() will set the young bit
  92  * for us as long as the page is marked present in the corresponding Linux
  93  * PTE entry.  Again, ptep_set_access_flags() will ensure that the TLB is
  94  * up to date.
  95  *
  96  * However, when the "young" bit is cleared, we deny access to the page
  97  * by clearing the hardware PTE.  Currently Linux does not flush the TLB
  98  * for us in this case, which means the TLB will retain the transation
  99  * until either the TLB entry is evicted under pressure, or a context
 100  * switch which changes the user space mapping occurs.
 101  */
 102 #define PTRS_PER_PTE            512
 103 #define PTRS_PER_PMD            1
 104 #define PTRS_PER_PGD            2048
 105
 106 #define PTE_HWTABLE_PTRS        (PTRS_PER_PTE)
 107 #define PTE_HWTABLE_OFF         (PTE_HWTABLE_PTRS * sizeof(pte_t))
 108 #define PTE_HWTABLE_SIZE        (PTRS_PER_PTE * sizeof(u32))
 109
 110 /*
 111  * PMD_SHIFT determines the size of the area a second-level page table can map
 112  * PGDIR_SHIFT determines what a third-level page table entry can map
 113  */
 114 #define PMD_SHIFT               21
 115 #define PGDIR_SHIFT             21
 116
 117 #define LIBRARY_TEXT_START      0x0c000000
 118
 119 #ifndef __ASSEMBLY__
 120 extern void __pte_error(const char *file, int line, pte_t);
 121 extern void __pmd_error(const char *file, int line, pmd_t);
 122 extern void __pgd_error(const char *file, int line, pgd_t);
 123
 124 #define pte_ERROR(pte)          __pte_error(__FILE__, __LINE__, pte)
 125 #define pmd_ERROR(pmd)          __pmd_error(__FILE__, __LINE__, pmd)
 126 #define pgd_ERROR(pgd)          __pgd_error(__FILE__, __LINE__, pgd)
 127 #endif /* !__ASSEMBLY__ */
 128
 129 #define PMD_SIZE                (1UL << PMD_SHIFT)
 130 #define PMD_MASK                (~(PMD_SIZE-1))
 131 #define PGDIR_SIZE              (1UL << PGDIR_SHIFT)
 132 #define PGDIR_MASK              (~(PGDIR_SIZE-1))
 133
 134 /*
 135  * This is the lowest virtual address we can permit any user space
 136  * mapping to be mapped at.  This is particularly important for
 137  * non-high vector CPUs.
 138  */
 139 #define FIRST_USER_ADDRESS      PAGE_SIZE
 140
 141 #define USER_PTRS_PER_PGD       (TASK_SIZE / PGDIR_SIZE)
 142
 143 /*
 144  * section address mask and size definitions.
 145  */
 146 #define SECTION_SHIFT           20
 147 #define SECTION_SIZE            (1UL << SECTION_SHIFT)
 148 #define SECTION_MASK            (~(SECTION_SIZE-1))
 149
 150 /*
 151  * ARMv6 supersection address mask and size definitions.
 152  */
 153 #define SUPERSECTION_SHIFT      24
 154 #define SUPERSECTION_SIZE       (1UL << SUPERSECTION_SHIFT)
 155 #define SUPERSECTION_MASK       (~(SUPERSECTION_SIZE-1))
 156
 157 /*
 158  * "Linux" PTE definitions.
 159  *
 160  * We keep two sets of PTEs - the hardware and the linux version.
 161  * This allows greater flexibility in the way we map the Linux bits
 162  * onto the hardware tables, and allows us to have YOUNG and DIRTY
 163  * bits.
 164  *
 165  * The PTE table pointer refers to the hardware entries; the "Linux"
 166  * entries are stored 1024 bytes below.
 167  */
 168 #define L_PTE_PRESENT           (_AT(pteval_t, 1) << 0)
 169 #define L_PTE_YOUNG             (_AT(pteval_t, 1) << 1)
 170 #define L_PTE_FILE              (_AT(pteval_t, 1) << 2) /* only when !PRESENT */
 171 #define L_PTE_DIRTY             (_AT(pteval_t, 1) << 6)
 172 #define L_PTE_RDONLY            (_AT(pteval_t, 1) << 7)
 173 #define L_PTE_USER              (_AT(pteval_t, 1) << 8)
 174 #define L_PTE_XN                (_AT(pteval_t, 1) << 9)
 175 #define L_PTE_SHARED            (_AT(pteval_t, 1) << 10)        /* shared(v6), coherent(xsc3) */
 176
 177 /*
 178  * These are the memory types, defined to be compatible with
 179  * pre-ARMv6 CPUs cacheable and bufferable bits:   XXCB
 180  */
 181 #define L_PTE_MT_UNCACHED       (_AT(pteval_t, 0x00) << 2)      /* 0000 */
 182 #define L_PTE_MT_BUFFERABLE     (_AT(pteval_t, 0x01) << 2)      /* 0001 */
 183 #define L_PTE_MT_WRITETHROUGH   (_AT(pteval_t, 0x02) << 2)      /* 0010 */
 184 #define L_PTE_MT_WRITEBACK      (_AT(pteval_t, 0x03) << 2)      /* 0011 */
 185 #define L_PTE_MT_MINICACHE      (_AT(pteval_t, 0x06) << 2)      /* 0110 (sa1100, xscale) */
 186 #define L_PTE_MT_WRITEALLOC     (_AT(pteval_t, 0x07) << 2)      /* 0111 */
 187 #define L_PTE_MT_DEV_SHARED     (_AT(pteval_t, 0x04) << 2)      /* 0100 */
 188 #define L_PTE_MT_DEV_NONSHARED  (_AT(pteval_t, 0x0c) << 2)      /* 1100 */
 189 #define L_PTE_MT_DEV_WC         (_AT(pteval_t, 0x09) << 2)      /* 1001 */
 190 #define L_PTE_MT_DEV_CACHED     (_AT(pteval_t, 0x0b) << 2)      /* 1011 */
 191 #define L_PTE_MT_MASK           (_AT(pteval_t, 0x0f) << 2)
 192
 193 #ifndef __ASSEMBLY__
 194
 195 /*
 196  * The pgprot_* and protection_map entries will be fixed up in runtime
 197  * to include the cachable and bufferable bits based on memory policy,
 198  * as well as any architecture dependent bits like global/ASID and SMP
 199  * shared mapping bits.
 200  */
 201 #define _L_PTE_DEFAULT  L_PTE_PRESENT | L_PTE_YOUNG
 202
 203 extern pgprot_t         pgprot_user;
 204 extern pgprot_t         pgprot_kernel;
 205
 206 #define _MOD_PROT(p, b) __pgprot(pgprot_val(p) | (b))
 207
 208 #define PAGE_NONE               _MOD_PROT(pgprot_user, L_PTE_XN | L_PTE_RDONLY)
 209 #define PAGE_SHARED             _MOD_PROT(pgprot_user, L_PTE_USER | L_PTE_XN)
 210 #define PAGE_SHARED_EXEC        _MOD_PROT(pgprot_user, L_PTE_USER)
 211 #define PAGE_COPY               _MOD_PROT(pgprot_user, L_PTE_USER | L_PTE_RDONLY | L_PTE_XN)
 212 #define PAGE_COPY_EXEC          _MOD_PROT(pgprot_user, L_PTE_USER | L_PTE_RDONLY)
 213 #define PAGE_READONLY           _MOD_PROT(pgprot_user, L_PTE_USER | L_PTE_RDONLY | L_PTE_XN)
 214 #define PAGE_READONLY_EXEC      _MOD_PROT(pgprot_user, L_PTE_USER | L_PTE_RDONLY)
 215 #define PAGE_KERNEL             _MOD_PROT(pgprot_kernel, L_PTE_XN)
 216 #define PAGE_KERNEL_EXEC        pgprot_kernel
 217
 218 #define __PAGE_NONE             __pgprot(_L_PTE_DEFAULT | L_PTE_RDONLY | L_PTE_XN)
 219 #define __PAGE_SHARED           __pgprot(_L_PTE_DEFAULT | L_PTE_USER | L_PTE_XN)
 220 #define __PAGE_SHARED_EXEC      __pgprot(_L_PTE_DEFAULT | L_PTE_USER)
 221 #define __PAGE_COPY             __pgprot(_L_PTE_DEFAULT | L_PTE_USER | L_PTE_RDONLY | L_PTE_XN)
 222 #define __PAGE_COPY_EXEC        __pgprot(_L_PTE_DEFAULT | L_PTE_USER | L_PTE_RDONLY)
 223 #define __PAGE_READONLY         __pgprot(_L_PTE_DEFAULT | L_PTE_USER | L_PTE_RDONLY | L_PTE_XN)
 224 #define __PAGE_READONLY_EXEC    __pgprot(_L_PTE_DEFAULT | L_PTE_USER | L_PTE_RDONLY)
 225
 226 #define __pgprot_modify(prot,mask,bits)         \
 227         __pgprot((pgprot_val(prot) & ~(mask)) | (bits))
 228
 229 #define pgprot_noncached(prot) \
 230         __pgprot_modify(prot, L_PTE_MT_MASK, L_PTE_MT_UNCACHED)
 231
 232 #define pgprot_writecombine(prot) \
 233         __pgprot_modify(prot, L_PTE_MT_MASK, L_PTE_MT_BUFFERABLE)
 234
 235 #ifdef CONFIG_ARM_DMA_MEM_BUFFERABLE
 236 #define pgprot_dmacoherent(prot) \
 237         __pgprot_modify(prot, L_PTE_MT_MASK, L_PTE_MT_BUFFERABLE | L_PTE_XN)
 238 #define __HAVE_PHYS_MEM_ACCESS_PROT
 239 struct file;
 240 extern pgprot_t phys_mem_access_prot(struct file *file, unsigned long pfn,
 241                                      unsigned long size, pgprot_t vma_prot);
 242 #else
 243 #define pgprot_dmacoherent(prot) \
 244         __pgprot_modify(prot, L_PTE_MT_MASK, L_PTE_MT_UNCACHED | L_PTE_XN)
 245 #endif
 246
 247 #endif /* __ASSEMBLY__ */
 248
 249 /*
 250  * The table below defines the page protection levels that we insert into our
 251  * Linux page table version.  These get translated into the best that the
 252  * architecture can perform.  Note that on most ARM hardware:
 253  *  1) We cannot do execute protection
 254  *  2) If we could do execute protection, then read is implied
 255  *  3) write implies read permissions
 256  */
 257 #define __P000  __PAGE_NONE
 258 #define __P001  __PAGE_READONLY
 259 #define __P010  __PAGE_COPY
 260 #define __P011  __PAGE_COPY
 261 #define __P100  __PAGE_READONLY_EXEC
 262 #define __P101  __PAGE_READONLY_EXEC
 263 #define __P110  __PAGE_COPY_EXEC
 264 #define __P111  __PAGE_COPY_EXEC
 265
 266 #define __S000  __PAGE_NONE
 267 #define __S001  __PAGE_READONLY
 268 #define __S010  __PAGE_SHARED
 269 #define __S011  __PAGE_SHARED
 270 #define __S100  __PAGE_READONLY_EXEC
 271 #define __S101  __PAGE_READONLY_EXEC
 272 #define __S110  __PAGE_SHARED_EXEC
 273 #define __S111  __PAGE_SHARED_EXEC
 274
 275 #ifndef __ASSEMBLY__
 276 /*
 277  * ZERO_PAGE is a global shared page that is always zero: used
 278  * for zero-mapped memory areas etc..
 279  */
 280 extern struct page *empty_zero_page;
 281 #define ZERO_PAGE(vaddr)        (empty_zero_page)
 282
 283
 284 extern pgd_t swapper_pg_dir[PTRS_PER_PGD];
 285
 286 /* to find an entry in a page-table-directory */
 287 #define pgd_index(addr)         ((addr) >> PGDIR_SHIFT)
 288
 289 #define pgd_offset(mm, addr)    ((mm)->pgd + pgd_index(addr))
 290
 291 /* to find an entry in a kernel page-table-directory */
 292 #define pgd_offset_k(addr)      pgd_offset(&init_mm, addr)
 293
 294 /*
 295  * The "pgd_xxx()" functions here are trivial for a folded two-level
 296  * setup: the pgd is never bad, and a pmd always exists (as it's folded
 297  * into the pgd entry)
 298  */
 299 #define pgd_none(pgd)           (0)
 300 #define pgd_bad(pgd)            (0)
 301 #define pgd_present(pgd)        (1)
 302 #define pgd_clear(pgdp)         do { } while (0)
 303 #define set_pgd(pgd,pgdp)       do { } while (0)
 304 #define set_pud(pud,pudp)       do { } while (0)
 305
 306
 307 /* Find an entry in the second-level page table.. */
 308 #define pmd_offset(dir, addr)   ((pmd_t *)(dir))
 309
 310 #define pmd_none(pmd)           (!pmd_val(pmd))
 311 #define pmd_present(pmd)        (pmd_val(pmd))
 312 #define pmd_bad(pmd)            (pmd_val(pmd) & 2)
 313
 314 #define copy_pmd(pmdpd,pmdps)           \
 315         do {                            \
 316                 pmdpd[0] = pmdps[0];    \
 317                 pmdpd[1] = pmdps[1];    \
 318                 flush_pmd_entry(pmdpd); \
 319         } while (0)
 320
 321 #define pmd_clear(pmdp)                 \
 322         do {                            \
 323                 pmdp[0] = __pmd(0);     \
 324                 pmdp[1] = __pmd(0);     \
 325                 clean_pmd_entry(pmdp);  \
 326         } while (0)
 327
 328 static inline pte_t *pmd_page_vaddr(pmd_t pmd)
 329 {
 330         return __va(pmd_val(pmd) & PAGE_MASK);
 331 }
 332
 333 #define pmd_page(pmd)           pfn_to_page(__phys_to_pfn(pmd_val(pmd)))
 334
 335 /* we don't need complex calculations here as the pmd is folded into the pgd */
 336 #define pmd_addr_end(addr,end)  (end)
 337
 338
 339 #ifndef CONFIG_HIGHPTE
 340 #define __pte_map(pmd)          pmd_page_vaddr(*(pmd))
 341 #define __pte_unmap(pte)        do { } while (0)
 342 #else
 343 #define __pte_map(pmd)          (pte_t *)kmap_atomic(pmd_page(*(pmd)))
 344 #define __pte_unmap(pte)        kunmap_atomic(pte)
 345 #endif
 346
 347 #define pte_index(addr)         (((addr) >> PAGE_SHIFT) & (PTRS_PER_PTE - 1))
 348
 349 #define pte_offset_kernel(pmd,addr)     (pmd_page_vaddr(*(pmd)) + pte_index(addr))
 350
 351 #define pte_offset_map(pmd,addr)        (__pte_map(pmd) + pte_index(addr))
 352 #define pte_unmap(pte)                  __pte_unmap(pte)
 353
 354 #define pte_pfn(pte)            (pte_val(pte) >> PAGE_SHIFT)
 355 #define pfn_pte(pfn,prot)       __pte(__pfn_to_phys(pfn) | pgprot_val(prot))
 356
 357 #define pte_page(pte)           pfn_to_page(pte_pfn(pte))
 358 #define mk_pte(page,prot)       pfn_pte(page_to_pfn(page), prot)
 359
 360 #define set_pte_ext(ptep,pte,ext) cpu_set_pte_ext(ptep,pte,ext)
 361 #define pte_clear(mm,addr,ptep) set_pte_ext(ptep, __pte(0), 0)
 362
 363 #if __LINUX_ARM_ARCH__ < 6
 364 static inline void __sync_icache_dcache(pte_t pteval)
 365 {
 366 }
 367 #else
 368 extern void __sync_icache_dcache(pte_t pteval);
 369 #endif
 370
 371 static inline void set_pte_at(struct mm_struct *mm, unsigned long addr,
 372                               pte_t *ptep, pte_t pteval)
 373 {
 374         if (addr >= TASK_SIZE)
 375                 set_pte_ext(ptep, pteval, 0);
 376         else {
 377                 __sync_icache_dcache(pteval);
 378                 set_pte_ext(ptep, pteval, PTE_EXT_NG);
 379         }
 380 }
 381
 382 #define pte_none(pte)           (!pte_val(pte))
 383 #define pte_present(pte)        (pte_val(pte) & L_PTE_PRESENT)
 384 #define pte_write(pte)          (!(pte_val(pte) & L_PTE_RDONLY))
 385 #define pte_dirty(pte)          (pte_val(pte) & L_PTE_DIRTY)
 386 #define pte_young(pte)          (pte_val(pte) & L_PTE_YOUNG)
 387 #define pte_exec(pte)           (!(pte_val(pte) & L_PTE_XN))
 388 #define pte_special(pte)        (0)
 389
 390 #define pte_present_user(pte) \
 391         ((pte_val(pte) & (L_PTE_PRESENT | L_PTE_USER)) == \
 392          (L_PTE_PRESENT | L_PTE_USER))
 393
 394 #define PTE_BIT_FUNC(fn,op) \
 395 static inline pte_t pte_##fn(pte_t pte) { pte_val(pte) op; return pte; }
 396
 397 PTE_BIT_FUNC(wrprotect, |= L_PTE_RDONLY);
 398 PTE_BIT_FUNC(mkwrite,   &= ~L_PTE_RDONLY);
 399 PTE_BIT_FUNC(mkclean,   &= ~L_PTE_DIRTY);
 400 PTE_BIT_FUNC(mkdirty,   |= L_PTE_DIRTY);
 401 PTE_BIT_FUNC(mkold,     &= ~L_PTE_YOUNG);
 402 PTE_BIT_FUNC(mkyoung,   |= L_PTE_YOUNG);
 403
 404 static inline pte_t pte_mkspecial(pte_t pte) { return pte; }
 405
 406 static inline pte_t pte_modify(pte_t pte, pgprot_t newprot)
 407 {
 408         const pteval_t mask = L_PTE_XN | L_PTE_RDONLY | L_PTE_USER;
 409         pte_val(pte) = (pte_val(pte) & ~mask) | (pgprot_val(newprot) & mask);
 410         return pte;
 411 }
 412
 413 /*
 414  * Encode and decode a swap entry.  Swap entries are stored in the Linux
 415  * page tables as follows:
 416  *
 417  *   3 3 2 2 2 2 2 2 2 2 2 2 1 1 1 1 1 1 1 1 1 1
 418  *   1 0 9 8 7 6 5 4 3 2 1 0 9 8 7 6 5 4 3 2 1 0 9 8 7 6 5 4 3 2 1 0
 419  *   <--------------- offset --------------------> <- type --> 0 0 0
 420  *
 421  * This gives us up to 63 swap files and 32GB per swap file.  Note that
 422  * the offset field is always non-zero.
 423  */
 424 #define __SWP_TYPE_SHIFT        3
 425 #define __SWP_TYPE_BITS         6
 426 #define __SWP_TYPE_MASK         ((1 << __SWP_TYPE_BITS) - 1)
 427 #define __SWP_OFFSET_SHIFT      (__SWP_TYPE_BITS + __SWP_TYPE_SHIFT)
 428
 429 #define __swp_type(x)           (((x).val >> __SWP_TYPE_SHIFT) & __SWP_TYPE_MASK)
 430 #define __swp_offset(x)         ((x).val >> __SWP_OFFSET_SHIFT)
 431 #define __swp_entry(type,offset) ((swp_entry_t) { ((type) << __SWP_TYPE_SHIFT) | ((offset) << __SWP_OFFSET_SHIFT) })
 432
 433 #define __pte_to_swp_entry(pte) ((swp_entry_t) { pte_val(pte) })
 434 #define __swp_entry_to_pte(swp) ((pte_t) { (swp).val })
 435
 436 /*
 437  * It is an error for the kernel to have more swap files than we can
 438  * encode in the PTEs.  This ensures that we know when MAX_SWAPFILES
 439  * is increased beyond what we presently support.
 440  */
 441 #define MAX_SWAPFILES_CHECK() BUILD_BUG_ON(MAX_SWAPFILES_SHIFT > __SWP_TYPE_BITS)
 442
 443 /*
 444  * Encode and decode a file entry.  File entries are stored in the Linux
 445  * page tables as follows:
 446  *
 447  *   3 3 2 2 2 2 2 2 2 2 2 2 1 1 1 1 1 1 1 1 1 1
 448  *   1 0 9 8 7 6 5 4 3 2 1 0 9 8 7 6 5 4 3 2 1 0 9 8 7 6 5 4 3 2 1 0
 449  *   <----------------------- offset ------------------------> 1 0 0
 450  */
 451 #define pte_file(pte)           (pte_val(pte) & L_PTE_FILE)
 452 #define pte_to_pgoff(x)         (pte_val(x) >> 3)
 453 #define pgoff_to_pte(x)         __pte(((x) << 3) | L_PTE_FILE)
 454
 455 #define PTE_FILE_MAX_BITS       29
 456
 457 /* Needs to be defined here and not in linux/mm.h, as it is arch dependent */
 458 /* FIXME: this is not correct */
 459 #define kern_addr_valid(addr)   (1)
 460
 461 #include <asm-generic/pgtable.h>
 462
 463 /*
 464  * We provide our own arch_get_unmapped_area to cope with VIPT caches.
 465  */
 466 #define HAVE_ARCH_UNMAPPED_AREA
 467
 468 /*
 469  * remap a physical page `pfn' of size `size' with page protection `prot'
 470  * into virtual address `from'
 471  */
 472 #define io_remap_pfn_range(vma,from,pfn,size,prot) \
 473                 remap_pfn_range(vma, from, pfn, size, prot)
 474
 475 #define pgtable_cache_init() do { } while (0)
 476
 477 void identity_mapping_add(pgd_t *, unsigned long, unsigned long);
 478 void identity_mapping_del(pgd_t *, unsigned long, unsigned long);
 479
 480 #endif /* !__ASSEMBLY__ */
 481
 482 #endif /* CONFIG_MMU */
 483
 484 #endif /* _ASMARM_PGTABLE_H */