arch/xtensa/include/asm/pgtable.h

   1 /*
   2  * include/asm-xtensa/pgtable.h
   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  * Copyright (C) 2001 - 2013 Tensilica Inc.
   9  */
  10
  11 #ifndef _XTENSA_PGTABLE_H
  12 #define _XTENSA_PGTABLE_H
  13
  14 #include <asm-generic/pgtable-nopmd.h>
  15 #include <asm/page.h>
  16 #include <asm/kmem_layout.h>
  17
  18 /*
  19  * We only use two ring levels, user and kernel space.
  20  */
  21
  22 #ifdef CONFIG_MMU
  23 #define USER_RING               1       /* user ring level */
  24 #else
  25 #define USER_RING               0
  26 #endif
  27 #define KERNEL_RING             0       /* kernel ring level */
  28
  29 /*
  30  * The Xtensa architecture port of Linux has a two-level page table system,
  31  * i.e. the logical three-level Linux page table layout is folded.
  32  * Each task has the following memory page tables:
  33  *
  34  *   PGD table (page directory), ie. 3rd-level page table:
  35  *      One page (4 kB) of 1024 (PTRS_PER_PGD) pointers to PTE tables
  36  *      (Architectures that don't have the PMD folded point to the PMD tables)
  37  *
  38  *      The pointer to the PGD table for a given task can be retrieved from
  39  *      the task structure (struct task_struct*) t, e.g. current():
  40  *        (t->mm ? t->mm : t->active_mm)->pgd
  41  *
  42  *   PMD tables (page middle-directory), ie. 2nd-level page tables:
  43  *      Absent for the Xtensa architecture (folded, PTRS_PER_PMD == 1).
  44  *
  45  *   PTE tables (page table entry), ie. 1st-level page tables:
  46  *      One page (4 kB) of 1024 (PTRS_PER_PTE) PTEs with a special PTE
  47  *      invalid_pte_table for absent mappings.
  48  *
  49  * The individual pages are 4 kB big with special pages for the empty_zero_page.
  50  */
  51
  52 #define PGDIR_SHIFT     22
  53 #define PGDIR_SIZE      (1UL << PGDIR_SHIFT)
  54 #define PGDIR_MASK      (~(PGDIR_SIZE-1))
  55
  56 /*
  57  * Entries per page directory level: we use two-level, so
  58  * we don't really have any PMD directory physically.
  59  */
  60 #define PTRS_PER_PTE            1024
  61 #define PTRS_PER_PTE_SHIFT      10
  62 #define PTRS_PER_PGD            1024
  63 #define PGD_ORDER               0
  64 #define USER_PTRS_PER_PGD       (TASK_SIZE/PGDIR_SIZE)
  65 #define FIRST_USER_ADDRESS      0UL
  66 #define FIRST_USER_PGD_NR       (FIRST_USER_ADDRESS >> PGDIR_SHIFT)
  67
  68 /*
  69  * Virtual memory area. We keep a distance to other memory regions to be
  70  * on the safe side. We also use this area for cache aliasing.
  71  */
  72 #define VMALLOC_START           (XCHAL_KSEG_CACHED_VADDR - 0x10000000)
  73 #define VMALLOC_END             (VMALLOC_START + 0x07FEFFFF)
  74 #define TLBTEMP_BASE_1          (VMALLOC_END + 1)
  75 #define TLBTEMP_BASE_2          (TLBTEMP_BASE_1 + DCACHE_WAY_SIZE)
  76 #if 2 * DCACHE_WAY_SIZE > ICACHE_WAY_SIZE
  77 #define TLBTEMP_SIZE            (2 * DCACHE_WAY_SIZE)
  78 #else
  79 #define TLBTEMP_SIZE            ICACHE_WAY_SIZE
  80 #endif
  81
  82 /*
  83  * For the Xtensa architecture, the PTE layout is as follows:
  84  *
  85  *              31------12  11  10-9   8-6  5-4  3-2  1-0
  86  *              +-----------------------------------------+
  87  *              |           |   Software   |   HARDWARE   |
  88  *              |    PPN    |          ADW | RI |Attribute|
  89  *              +-----------------------------------------+
  90  *   pte_none   |             MBZ          | 01 | 11 | 00 |
  91  *              +-----------------------------------------+
  92  *   present    |    PPN    | 0 | 00 | ADW | RI | CA | wx |
  93  *              +- - - - - - - - - - - - - - - - - - - - -+
  94  *   (PAGE_NONE)|    PPN    | 0 | 00 | ADW | 01 | 11 | 11 |
  95  *              +-----------------------------------------+
  96  *   swap       |     index     |   type   | 01 | 11 | 00 |
  97  *              +-----------------------------------------+
  98  *
  99  * For T1050 hardware and earlier the layout differs for present and (PAGE_NONE)
 100  *              +-----------------------------------------+
 101  *   present    |    PPN    | 0 | 00 | ADW | RI | CA | w1 |
 102  *              +-----------------------------------------+
 103  *   (PAGE_NONE)|    PPN    | 0 | 00 | ADW | 01 | 01 | 00 |
 104  *              +-----------------------------------------+
 105  *
 106  *  Legend:
 107  *   PPN        Physical Page Number
 108  *   ADW        software: accessed (young) / dirty / writable
 109  *   RI         ring (0=privileged, 1=user, 2 and 3 are unused)
 110  *   CA         cache attribute: 00 bypass, 01 writeback, 10 writethrough
 111  *              (11 is invalid and used to mark pages that are not present)
 112  *   w          page is writable (hw)
 113  *   x          page is executable (hw)
 114  *   index      swap offset / PAGE_SIZE (bit 11-31: 21 bits -> 8 GB)
 115  *              (note that the index is always non-zero)
 116  *   type       swap type (5 bits -> 32 types)
 117  *
 118  *  Notes:
 119  *   - (PROT_NONE) is a special case of 'present' but causes an exception for
 120  *     any access (read, write, and execute).
 121  *   - 'multihit-exception' has the highest priority of all MMU exceptions,
 122  *     so the ring must be set to 'RING_USER' even for 'non-present' pages.
 123  *   - on older hardware, the exectuable flag was not supported and
 124  *     used as a 'valid' flag, so it needs to be always set.
 125  *   - we need to keep track of certain flags in software (dirty and young)
 126  *     to do this, we use write exceptions and have a separate software w-flag.
 127  *   - attribute value 1101 (and 1111 on T1050 and earlier) is reserved
 128  */
 129
 130 #define _PAGE_ATTRIB_MASK       0xf
 131
 132 #define _PAGE_HW_EXEC           (1<<0)  /* hardware: page is executable */
 133 #define _PAGE_HW_WRITE          (1<<1)  /* hardware: page is writable */
 134
 135 #define _PAGE_CA_BYPASS         (0<<2)  /* bypass, non-speculative */
 136 #define _PAGE_CA_WB             (1<<2)  /* write-back */
 137 #define _PAGE_CA_WT             (2<<2)  /* write-through */
 138 #define _PAGE_CA_MASK           (3<<2)
 139 #define _PAGE_CA_INVALID        (3<<2)
 140
 141 /* We use invalid attribute values to distinguish special pte entries */
 142 #if XCHAL_HW_VERSION_MAJOR < 2000
 143 #define _PAGE_HW_VALID          0x01    /* older HW needed this bit set */
 144 #define _PAGE_NONE              0x04
 145 #else
 146 #define _PAGE_HW_VALID          0x00
 147 #define _PAGE_NONE              0x0f
 148 #endif
 149
 150 #define _PAGE_USER              (1<<4)  /* user access (ring=1) */
 151
 152 /* Software */
 153 #define _PAGE_WRITABLE_BIT      6
 154 #define _PAGE_WRITABLE          (1<<6)  /* software: page writable */
 155 #define _PAGE_DIRTY             (1<<7)  /* software: page dirty */
 156 #define _PAGE_ACCESSED          (1<<8)  /* software: page accessed (read) */
 157
 158 #ifdef CONFIG_MMU
 159
 160 #define _PAGE_CHG_MASK     (PAGE_MASK | _PAGE_ACCESSED | _PAGE_DIRTY)
 161 #define _PAGE_PRESENT      (_PAGE_HW_VALID | _PAGE_CA_WB | _PAGE_ACCESSED)
 162
 163 #define PAGE_NONE          __pgprot(_PAGE_NONE | _PAGE_USER)
 164 #define PAGE_COPY          __pgprot(_PAGE_PRESENT | _PAGE_USER)
 165 #define PAGE_COPY_EXEC     __pgprot(_PAGE_PRESENT | _PAGE_USER | _PAGE_HW_EXEC)
 166 #define PAGE_READONLY      __pgprot(_PAGE_PRESENT | _PAGE_USER)
 167 #define PAGE_READONLY_EXEC __pgprot(_PAGE_PRESENT | _PAGE_USER | _PAGE_HW_EXEC)
 168 #define PAGE_SHARED        __pgprot(_PAGE_PRESENT | _PAGE_USER | _PAGE_WRITABLE)
 169 #define PAGE_SHARED_EXEC \
 170         __pgprot(_PAGE_PRESENT | _PAGE_USER | _PAGE_WRITABLE | _PAGE_HW_EXEC)
 171 #define PAGE_KERNEL        __pgprot(_PAGE_PRESENT | _PAGE_HW_WRITE)
 172 #define PAGE_KERNEL_EXEC   __pgprot(_PAGE_PRESENT|_PAGE_HW_WRITE|_PAGE_HW_EXEC)
 173
 174 #if (DCACHE_WAY_SIZE > PAGE_SIZE)
 175 # define _PAGE_DIRECTORY   (_PAGE_HW_VALID | _PAGE_ACCESSED | _PAGE_CA_BYPASS)
 176 #else
 177 # define _PAGE_DIRECTORY   (_PAGE_HW_VALID | _PAGE_ACCESSED | _PAGE_CA_WB)
 178 #endif
 179
 180 #else /* no mmu */
 181
 182 # define _PAGE_CHG_MASK  (PAGE_MASK | _PAGE_ACCESSED | _PAGE_DIRTY)
 183 # define PAGE_NONE       __pgprot(0)
 184 # define PAGE_SHARED     __pgprot(0)
 185 # define PAGE_COPY       __pgprot(0)
 186 # define PAGE_READONLY   __pgprot(0)
 187 # define PAGE_KERNEL     __pgprot(0)
 188
 189 #endif
 190
 191 /*
 192  * On certain configurations of Xtensa MMUs (eg. the initial Linux config),
 193  * the MMU can't do page protection for execute, and considers that the same as
 194  * read.  Also, write permissions may imply read permissions.
 195  * What follows is the closest we can get by reasonable means..
 196  * See linux/mm/mmap.c for protection_map[] array that uses these definitions.
 197  */
 198 #define __P000  PAGE_NONE               /* private --- */
 199 #define __P001  PAGE_READONLY           /* private --r */
 200 #define __P010  PAGE_COPY               /* private -w- */
 201 #define __P011  PAGE_COPY               /* private -wr */
 202 #define __P100  PAGE_READONLY_EXEC      /* private x-- */
 203 #define __P101  PAGE_READONLY_EXEC      /* private x-r */
 204 #define __P110  PAGE_COPY_EXEC          /* private xw- */
 205 #define __P111  PAGE_COPY_EXEC          /* private xwr */
 206
 207 #define __S000  PAGE_NONE               /* shared  --- */
 208 #define __S001  PAGE_READONLY           /* shared  --r */
 209 #define __S010  PAGE_SHARED             /* shared  -w- */
 210 #define __S011  PAGE_SHARED             /* shared  -wr */
 211 #define __S100  PAGE_READONLY_EXEC      /* shared  x-- */
 212 #define __S101  PAGE_READONLY_EXEC      /* shared  x-r */
 213 #define __S110  PAGE_SHARED_EXEC        /* shared  xw- */
 214 #define __S111  PAGE_SHARED_EXEC        /* shared  xwr */
 215
 216 #ifndef __ASSEMBLY__
 217
 218 #define pte_ERROR(e) \
 219         printk("%s:%d: bad pte %08lx.\n", __FILE__, __LINE__, pte_val(e))
 220 #define pgd_ERROR(e) \
 221         printk("%s:%d: bad pgd entry %08lx.\n", __FILE__, __LINE__, pgd_val(e))
 222
 223 extern unsigned long empty_zero_page[1024];
 224
 225 #define ZERO_PAGE(vaddr) (virt_to_page(empty_zero_page))
 226
 227 #ifdef CONFIG_MMU
 228 extern pgd_t swapper_pg_dir[PAGE_SIZE/sizeof(pgd_t)];
 229 extern void paging_init(void);
 230 #else
 231 # define swapper_pg_dir NULL
 232 static inline void paging_init(void) { }
 233 #endif
 234 static inline void pgtable_cache_init(void) { }
 235
 236 /*
 237  * The pmd contains the kernel virtual address of the pte page.
 238  */
 239 #define pmd_page_vaddr(pmd) ((unsigned long)(pmd_val(pmd) & PAGE_MASK))
 240 #define pmd_page(pmd) virt_to_page(pmd_val(pmd))
 241
 242 /*
 243  * pte status.
 244  */
 245 # define pte_none(pte)   (pte_val(pte) == (_PAGE_CA_INVALID | _PAGE_USER))
 246 #if XCHAL_HW_VERSION_MAJOR < 2000
 247 # define pte_present(pte) ((pte_val(pte) & _PAGE_CA_MASK) != _PAGE_CA_INVALID)
 248 #else
 249 # define pte_present(pte)                                               \
 250         (((pte_val(pte) & _PAGE_CA_MASK) != _PAGE_CA_INVALID)           \
 251          || ((pte_val(pte) & _PAGE_ATTRIB_MASK) == _PAGE_NONE))
 252 #endif
 253 #define pte_clear(mm,addr,ptep)                                         \
 254         do { update_pte(ptep, __pte(_PAGE_CA_INVALID | _PAGE_USER)); } while (0)
 255
 256 #define pmd_none(pmd)    (!pmd_val(pmd))
 257 #define pmd_present(pmd) (pmd_val(pmd) & PAGE_MASK)
 258 #define pmd_bad(pmd)     (pmd_val(pmd) & ~PAGE_MASK)
 259 #define pmd_clear(pmdp)  do { set_pmd(pmdp, __pmd(0)); } while (0)
 260
 261 static inline int pte_write(pte_t pte) { return pte_val(pte) & _PAGE_WRITABLE; }
 262 static inline int pte_dirty(pte_t pte) { return pte_val(pte) & _PAGE_DIRTY; }
 263 static inline int pte_young(pte_t pte) { return pte_val(pte) & _PAGE_ACCESSED; }
 264 static inline int pte_special(pte_t pte) { return 0; }
 265
 266 static inline pte_t pte_wrprotect(pte_t pte)
 267         { pte_val(pte) &= ~(_PAGE_WRITABLE | _PAGE_HW_WRITE); return pte; }
 268 static inline pte_t pte_mkclean(pte_t pte)
 269         { pte_val(pte) &= ~(_PAGE_DIRTY | _PAGE_HW_WRITE); return pte; }
 270 static inline pte_t pte_mkold(pte_t pte)
 271         { pte_val(pte) &= ~_PAGE_ACCESSED; return pte; }
 272 static inline pte_t pte_mkdirty(pte_t pte)
 273         { pte_val(pte) |= _PAGE_DIRTY; return pte; }
 274 static inline pte_t pte_mkyoung(pte_t pte)
 275         { pte_val(pte) |= _PAGE_ACCESSED; return pte; }
 276 static inline pte_t pte_mkwrite(pte_t pte)
 277         { pte_val(pte) |= _PAGE_WRITABLE; return pte; }
 278 static inline pte_t pte_mkspecial(pte_t pte)
 279         { return pte; }
 280
 281 #define pgprot_noncached(prot) (__pgprot(pgprot_val(prot) & ~_PAGE_CA_MASK))
 282
 283 /*
 284  * Conversion functions: convert a page and protection to a page entry,
 285  * and a page entry and page directory to the page they refer to.
 286  */
 287
 288 #define pte_pfn(pte)            (pte_val(pte) >> PAGE_SHIFT)
 289 #define pte_same(a,b)           (pte_val(a) == pte_val(b))
 290 #define pte_page(x)             pfn_to_page(pte_pfn(x))
 291 #define pfn_pte(pfn, prot)      __pte(((pfn) << PAGE_SHIFT) | pgprot_val(prot))
 292 #define mk_pte(page, prot)      pfn_pte(page_to_pfn(page), prot)
 293
 294 static inline pte_t pte_modify(pte_t pte, pgprot_t newprot)
 295 {
 296         return __pte((pte_val(pte) & _PAGE_CHG_MASK) | pgprot_val(newprot));
 297 }
 298
 299 /*
 300  * Certain architectures need to do special things when pte's
 301  * within a page table are directly modified.  Thus, the following
 302  * hook is made available.
 303  */
 304 static inline void update_pte(pte_t *ptep, pte_t pteval)
 305 {
 306         *ptep = pteval;
 307 #if (DCACHE_WAY_SIZE > PAGE_SIZE) && XCHAL_DCACHE_IS_WRITEBACK
 308         __asm__ __volatile__ ("dhwb %0, 0" :: "a" (ptep));
 309 #endif
 310
 311 }
 312
 313 struct mm_struct;
 314
 315 static inline void
 316 set_pte_at(struct mm_struct *mm, unsigned long addr, pte_t *ptep, pte_t pteval)
 317 {
 318         update_pte(ptep, pteval);
 319 }
 320
 321 static inline void set_pte(pte_t *ptep, pte_t pteval)
 322 {
 323         update_pte(ptep, pteval);
 324 }
 325
 326 static inline void
 327 set_pmd(pmd_t *pmdp, pmd_t pmdval)
 328 {
 329         *pmdp = pmdval;
 330 }
 331
 332 struct vm_area_struct;
 333
 334 static inline int
 335 ptep_test_and_clear_young(struct vm_area_struct *vma, unsigned long addr,
 336                           pte_t *ptep)
 337 {
 338         pte_t pte = *ptep;
 339         if (!pte_young(pte))
 340                 return 0;
 341         update_pte(ptep, pte_mkold(pte));
 342         return 1;
 343 }
 344
 345 static inline pte_t
 346 ptep_get_and_clear(struct mm_struct *mm, unsigned long addr, pte_t *ptep)
 347 {
 348         pte_t pte = *ptep;
 349         pte_clear(mm, addr, ptep);
 350         return pte;
 351 }
 352
 353 static inline void
 354 ptep_set_wrprotect(struct mm_struct *mm, unsigned long addr, pte_t *ptep)
 355 {
 356         pte_t pte = *ptep;
 357         update_pte(ptep, pte_wrprotect(pte));
 358 }
 359
 360 /* to find an entry in a kernel page-table-directory */
 361 #define pgd_offset_k(address)   pgd_offset(&init_mm, address)
 362
 363 /* to find an entry in a page-table-directory */
 364 #define pgd_offset(mm,address)  ((mm)->pgd + pgd_index(address))
 365
 366 #define pgd_index(address)      ((address) >> PGDIR_SHIFT)
 367
 368 /* Find an entry in the second-level page table.. */
 369 #define pmd_offset(dir,address) ((pmd_t*)(dir))
 370
 371 /* Find an entry in the third-level page table.. */
 372 #define pte_index(address)      (((address) >> PAGE_SHIFT) & (PTRS_PER_PTE - 1))
 373 #define pte_offset_kernel(dir,addr)                                     \
 374         ((pte_t*) pmd_page_vaddr(*(dir)) + pte_index(addr))
 375 #define pte_offset_map(dir,addr)        pte_offset_kernel((dir),(addr))
 376 #define pte_unmap(pte)          do { } while (0)
 377
 378
 379 /*
 380  * Encode and decode a swap and file entry.
 381  */
 382 #define SWP_TYPE_BITS           5
 383 #define MAX_SWAPFILES_CHECK() BUILD_BUG_ON(MAX_SWAPFILES_SHIFT > SWP_TYPE_BITS)
 384
 385 #define __swp_type(entry)       (((entry).val >> 6) & 0x1f)
 386 #define __swp_offset(entry)     ((entry).val >> 11)
 387 #define __swp_entry(type,offs)  \
 388         ((swp_entry_t){((type) << 6) | ((offs) << 11) | \
 389          _PAGE_CA_INVALID | _PAGE_USER})
 390 #define __pte_to_swp_entry(pte) ((swp_entry_t) { pte_val(pte) })
 391 #define __swp_entry_to_pte(x)   ((pte_t) { (x).val })
 392
 393 #endif /*  !defined (__ASSEMBLY__) */
 394
 395
 396 #ifdef __ASSEMBLY__
 397
 398 /* Assembly macro _PGD_INDEX is the same as C pgd_index(unsigned long),
 399  *                _PGD_OFFSET as C pgd_offset(struct mm_struct*, unsigned long),
 400  *                _PMD_OFFSET as C pmd_offset(pgd_t*, unsigned long)
 401  *                _PTE_OFFSET as C pte_offset(pmd_t*, unsigned long)
 402  *
 403  * Note: We require an additional temporary register which can be the same as
 404  *       the register that holds the address.
 405  *
 406  * ((pte_t*) ((unsigned long)(pmd_val(*pmd) & PAGE_MASK)) + pte_index(addr))
 407  *
 408  */
 409 #define _PGD_INDEX(rt,rs)       extui   rt, rs, PGDIR_SHIFT, 32-PGDIR_SHIFT
 410 #define _PTE_INDEX(rt,rs)       extui   rt, rs, PAGE_SHIFT, PTRS_PER_PTE_SHIFT
 411
 412 #define _PGD_OFFSET(mm,adr,tmp)         l32i    mm, mm, MM_PGD;         \
 413                                         _PGD_INDEX(tmp, adr);           \
 414                                         addx4   mm, tmp, mm
 415
 416 #define _PTE_OFFSET(pmd,adr,tmp)        _PTE_INDEX(tmp, adr);           \
 417                                         srli    pmd, pmd, PAGE_SHIFT;   \
 418                                         slli    pmd, pmd, PAGE_SHIFT;   \
 419                                         addx4   pmd, tmp, pmd
 420
 421 #else
 422
 423 #define kern_addr_valid(addr)   (1)
 424
 425 extern  void update_mmu_cache(struct vm_area_struct * vma,
 426                               unsigned long address, pte_t *ptep);
 427
 428 typedef pte_t *pte_addr_t;
 429
 430 #endif /* !defined (__ASSEMBLY__) */
 431
 432 #define __HAVE_ARCH_PTEP_TEST_AND_CLEAR_YOUNG
 433 #define __HAVE_ARCH_PTEP_GET_AND_CLEAR
 434 #define __HAVE_ARCH_PTEP_SET_WRPROTECT
 435 #define __HAVE_ARCH_PTEP_MKDIRTY
 436 #define __HAVE_ARCH_PTE_SAME
 437 /* We provide our own get_unmapped_area to cope with
 438  * SHM area cache aliasing for userland.
 439  */
 440 #define HAVE_ARCH_UNMAPPED_AREA
 441
 442 #include <asm-generic/pgtable.h>
 443
 444 #endif /* _XTENSA_PGTABLE_H */