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__
  36 extern pgd_t swapper_pg_dir[PTRS_PER_PGD];
  37 extern 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  */
  43 extern 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  */
 196 static inline int pte_write(pte_t pte)
 197 {
 198         return pte_val(pte) & _PAGE_RW;
 199 }
 200 static inline int pte_dirty(pte_t pte)
 201 {
 202         return pte_val(pte) & _PAGE_DIRTY;
 203 }
 204 static inline int pte_young(pte_t pte)
 205 {
 206         return pte_val(pte) & _PAGE_ACCESSED;
 207 }
 208 static 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  */
 216 static inline int pte_file(pte_t pte)
 217 {
 218         return pte_val(pte) & _PAGE_FILE;
 219 }
 220
 221 /* Mutator functions for PTE bits */
 222 static inline pte_t pte_wrprotect(pte_t pte)
 223 {
 224         set_pte(&pte, __pte(pte_val(pte) & ~_PAGE_RW));
 225         return pte;
 226 }
 227 static inline pte_t pte_mkclean(pte_t pte)
 228 {
 229         set_pte(&pte, __pte(pte_val(pte) & ~_PAGE_DIRTY));
 230         return pte;
 231 }
 232 static inline pte_t pte_mkold(pte_t pte)
 233 {
 234         set_pte(&pte, __pte(pte_val(pte) & ~_PAGE_ACCESSED));
 235         return pte;
 236 }
 237 static inline pte_t pte_mkwrite(pte_t pte)
 238 {
 239         set_pte(&pte, __pte(pte_val(pte) | _PAGE_RW));
 240         return pte;
 241 }
 242 static inline pte_t pte_mkdirty(pte_t pte)
 243 {
 244         set_pte(&pte, __pte(pte_val(pte) | _PAGE_DIRTY));
 245         return pte;
 246 }
 247 static inline pte_t pte_mkyoung(pte_t pte)
 248 {
 249         set_pte(&pte, __pte(pte_val(pte) | _PAGE_ACCESSED));
 250         return pte;
 251 }
 252 static 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
 260 static 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
 294 static 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
 324 struct vm_area_struct;
 325 extern 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
 361 typedef pte_t *pte_addr_t;
 362
 363 #define kern_addr_valid(addr)   (1)
 364
 365 #define io_remap_pfn_range(vma, vaddr, pfn, size, prot) \
 366         remap_pfn_range(vma, vaddr, pfn, size, prot)
 367
 368 /* No page table caches to initialize (?) */
 369 #define pgtable_cache_init()    do { } while(0)
 370
 371 #include <asm-generic/pgtable.h>
 372
 373 #endif /* !__ASSEMBLY__ */
 374
 375 #endif /* __ASM_AVR32_PGTABLE_H */