include/asm-cris/pgtable.h

   1 /*
   2  * CRIS pgtable.h - macros and functions to manipulate page tables.
   3  */
   4
   5 #ifndef _CRIS_PGTABLE_H
   6 #define _CRIS_PGTABLE_H
   7
   8 #include <asm-generic/4level-fixup.h>
   9
  10 #ifndef __ASSEMBLY__
  11 #include <linux/config.h>
  12 #include <linux/sched.h>
  13 #include <asm/mmu.h>
  14 #endif
  15 #include <asm/arch/pgtable.h>
  16
  17 /*
  18  * The Linux memory management assumes a three-level page table setup. On
  19  * CRIS, we use that, but "fold" the mid level into the top-level page
  20  * table. Since the MMU TLB is software loaded through an interrupt, it
  21  * supports any page table structure, so we could have used a three-level
  22  * setup, but for the amounts of memory we normally use, a two-level is
  23  * probably more efficient.
  24  *
  25  * This file contains the functions and defines necessary to modify and use
  26  * the CRIS page table tree.
  27  */
  28 #ifndef __ASSEMBLY__
  29 extern void paging_init(void);
  30 #endif
  31
  32 /* Certain architectures need to do special things when pte's
  33  * within a page table are directly modified.  Thus, the following
  34  * hook is made available.
  35  */
  36 #define set_pte(pteptr, pteval) ((*(pteptr)) = (pteval))
  37 #define set_pte_at(mm,addr,ptep,pteval) set_pte(ptep,pteval)
  38
  39 /*
  40  * (pmds are folded into pgds so this doesn't get actually called,
  41  * but the define is needed for a generic inline function.)
  42  */
  43 #define set_pmd(pmdptr, pmdval) (*(pmdptr) = pmdval)
  44 #define set_pgd(pgdptr, pgdval) (*(pgdptr) = pgdval)
  45
  46 /* PMD_SHIFT determines the size of the area a second-level page table can
  47  * map. It is equal to the page size times the number of PTE's that fit in
  48  * a PMD page. A PTE is 4-bytes in CRIS. Hence the following number.
  49  */
  50
  51 #define PMD_SHIFT       (PAGE_SHIFT + (PAGE_SHIFT-2))
  52 #define PMD_SIZE        (1UL << PMD_SHIFT)
  53 #define PMD_MASK        (~(PMD_SIZE-1))
  54
  55 /* PGDIR_SHIFT determines what a third-level page table entry can map.
  56  * Since we fold into a two-level structure, this is the same as PMD_SHIFT.
  57  */
  58
  59 #define PGDIR_SHIFT     PMD_SHIFT
  60 #define PGDIR_SIZE      (1UL << PGDIR_SHIFT)
  61 #define PGDIR_MASK      (~(PGDIR_SIZE-1))
  62
  63 /*
  64  * entries per page directory level: we use a two-level, so
  65  * we don't really have any PMD directory physically.
  66  * pointers are 4 bytes so we can use the page size and
  67  * divide it by 4 (shift by 2).
  68  */
  69 #define PTRS_PER_PTE    (1UL << (PAGE_SHIFT-2))
  70 #define PTRS_PER_PMD    1
  71 #define PTRS_PER_PGD    (1UL << (PAGE_SHIFT-2))
  72
  73 /* calculate how many PGD entries a user-level program can use
  74  * the first mappable virtual address is 0
  75  * (TASK_SIZE is the maximum virtual address space)
  76  */
  77
  78 #define USER_PTRS_PER_PGD       (TASK_SIZE/PGDIR_SIZE)
  79 #define FIRST_USER_ADDRESS      0
  80
  81 /* zero page used for uninitialized stuff */
  82 #ifndef __ASSEMBLY__
  83 extern unsigned long empty_zero_page;
  84 #define ZERO_PAGE(vaddr) (virt_to_page(empty_zero_page))
  85 #endif
  86
  87 /* number of bits that fit into a memory pointer */
  88 #define BITS_PER_PTR                    (8*sizeof(unsigned long))
  89
  90 /* to align the pointer to a pointer address */
  91 #define PTR_MASK                        (~(sizeof(void*)-1))
  92
  93 /* sizeof(void*)==1<<SIZEOF_PTR_LOG2 */
  94 /* 64-bit machines, beware!  SRB. */
  95 #define SIZEOF_PTR_LOG2                 2
  96
  97 /* to find an entry in a page-table */
  98 #define PAGE_PTR(address) \
  99 ((unsigned long)(address)>>(PAGE_SHIFT-SIZEOF_PTR_LOG2)&PTR_MASK&~PAGE_MASK)
 100
 101 /* to set the page-dir */
 102 #define SET_PAGE_DIR(tsk,pgdir)
 103
 104 #define pte_none(x)     (!pte_val(x))
 105 #define pte_present(x)  (pte_val(x) & _PAGE_PRESENT)
 106 #define pte_clear(mm,addr,xp)   do { pte_val(*(xp)) = 0; } while (0)
 107
 108 #define pmd_none(x)     (!pmd_val(x))
 109 /* by removing the _PAGE_KERNEL bit from the comparision, the same pmd_bad
 110  * works for both _PAGE_TABLE and _KERNPG_TABLE pmd entries.
 111  */
 112 #define pmd_bad(x)      ((pmd_val(x) & (~PAGE_MASK & ~_PAGE_KERNEL)) != _PAGE_TABLE)
 113 #define pmd_present(x)  (pmd_val(x) & _PAGE_PRESENT)
 114 #define pmd_clear(xp)   do { pmd_val(*(xp)) = 0; } while (0)
 115
 116 #ifndef __ASSEMBLY__
 117
 118 /*
 119  * The "pgd_xxx()" functions here are trivial for a folded two-level
 120  * setup: the pgd is never bad, and a pmd always exists (as it's folded
 121  * into the pgd entry)
 122  */
 123 extern inline int pgd_none(pgd_t pgd)           { return 0; }
 124 extern inline int pgd_bad(pgd_t pgd)            { return 0; }
 125 extern inline int pgd_present(pgd_t pgd)        { return 1; }
 126 extern inline void pgd_clear(pgd_t * pgdp)      { }
 127
 128 /*
 129  * The following only work if pte_present() is true.
 130  * Undefined behaviour if not..
 131  */
 132
 133 extern inline int pte_read(pte_t pte)           { return pte_val(pte) & _PAGE_READ; }
 134 extern inline int pte_write(pte_t pte)          { return pte_val(pte) & _PAGE_WRITE; }
 135 extern inline int pte_exec(pte_t pte)           { return pte_val(pte) & _PAGE_READ; }
 136 extern inline int pte_dirty(pte_t pte)          { return pte_val(pte) & _PAGE_MODIFIED; }
 137 extern inline int pte_young(pte_t pte)          { return pte_val(pte) & _PAGE_ACCESSED; }
 138 extern inline int pte_file(pte_t pte)           { return pte_val(pte) & _PAGE_FILE; }
 139
 140 extern inline pte_t pte_wrprotect(pte_t pte)
 141 {
 142         pte_val(pte) &= ~(_PAGE_WRITE | _PAGE_SILENT_WRITE);
 143         return pte;
 144 }
 145
 146 extern inline pte_t pte_rdprotect(pte_t pte)
 147 {
 148         pte_val(pte) &= ~(_PAGE_READ | _PAGE_SILENT_READ);
 149         return pte;
 150 }
 151
 152 extern inline pte_t pte_exprotect(pte_t pte)
 153 {
 154         pte_val(pte) &= ~(_PAGE_READ | _PAGE_SILENT_READ);
 155         return pte;
 156 }
 157
 158 extern inline pte_t pte_mkclean(pte_t pte)
 159 {
 160         pte_val(pte) &= ~(_PAGE_MODIFIED | _PAGE_SILENT_WRITE);
 161         return pte;
 162 }
 163
 164 extern inline pte_t pte_mkold(pte_t pte)
 165 {
 166         pte_val(pte) &= ~(_PAGE_ACCESSED | _PAGE_SILENT_READ);
 167         return pte;
 168 }
 169
 170 extern inline pte_t pte_mkwrite(pte_t pte)
 171 {
 172         pte_val(pte) |= _PAGE_WRITE;
 173         if (pte_val(pte) & _PAGE_MODIFIED)
 174                 pte_val(pte) |= _PAGE_SILENT_WRITE;
 175         return pte;
 176 }
 177
 178 extern inline pte_t pte_mkread(pte_t pte)
 179 {
 180         pte_val(pte) |= _PAGE_READ;
 181         if (pte_val(pte) & _PAGE_ACCESSED)
 182                 pte_val(pte) |= _PAGE_SILENT_READ;
 183         return pte;
 184 }
 185
 186 extern inline pte_t pte_mkexec(pte_t pte)
 187 {
 188         pte_val(pte) |= _PAGE_READ;
 189         if (pte_val(pte) & _PAGE_ACCESSED)
 190                 pte_val(pte) |= _PAGE_SILENT_READ;
 191         return pte;
 192 }
 193
 194 extern inline pte_t pte_mkdirty(pte_t pte)
 195 {
 196         pte_val(pte) |= _PAGE_MODIFIED;
 197         if (pte_val(pte) & _PAGE_WRITE)
 198                 pte_val(pte) |= _PAGE_SILENT_WRITE;
 199         return pte;
 200 }
 201
 202 extern inline pte_t pte_mkyoung(pte_t pte)
 203 {
 204         pte_val(pte) |= _PAGE_ACCESSED;
 205         if (pte_val(pte) & _PAGE_READ)
 206         {
 207                 pte_val(pte) |= _PAGE_SILENT_READ;
 208                 if ((pte_val(pte) & (_PAGE_WRITE | _PAGE_MODIFIED)) ==
 209                     (_PAGE_WRITE | _PAGE_MODIFIED))
 210                         pte_val(pte) |= _PAGE_SILENT_WRITE;
 211         }
 212         return pte;
 213 }
 214
 215 /*
 216  * Conversion functions: convert a page and protection to a page entry,
 217  * and a page entry and page directory to the page they refer to.
 218  */
 219
 220 /* What actually goes as arguments to the various functions is less than
 221  * obvious, but a rule of thumb is that struct page's goes as struct page *,
 222  * really physical DRAM addresses are unsigned long's, and DRAM "virtual"
 223  * addresses (the 0xc0xxxxxx's) goes as void *'s.
 224  */
 225
 226 extern inline pte_t __mk_pte(void * page, pgprot_t pgprot)
 227 {
 228         pte_t pte;
 229         /* the PTE needs a physical address */
 230         pte_val(pte) = __pa(page) | pgprot_val(pgprot);
 231         return pte;
 232 }
 233
 234 #define mk_pte(page, pgprot) __mk_pte(page_address(page), (pgprot))
 235
 236 #define mk_pte_phys(physpage, pgprot) \
 237 ({                                                                      \
 238         pte_t __pte;                                                    \
 239                                                                         \
 240         pte_val(__pte) = (physpage) + pgprot_val(pgprot);               \
 241         __pte;                                                          \
 242 })
 243
 244 extern inline pte_t pte_modify(pte_t pte, pgprot_t newprot)
 245 { pte_val(pte) = (pte_val(pte) & _PAGE_CHG_MASK) | pgprot_val(newprot); return pte; }
 246
 247
 248 /* pte_val refers to a page in the 0x4xxxxxxx physical DRAM interval
 249  * __pte_page(pte_val) refers to the "virtual" DRAM interval
 250  * pte_pagenr refers to the page-number counted starting from the virtual DRAM start
 251  */
 252
 253 extern inline unsigned long __pte_page(pte_t pte)
 254 {
 255         /* the PTE contains a physical address */
 256         return (unsigned long)__va(pte_val(pte) & PAGE_MASK);
 257 }
 258
 259 #define pte_pagenr(pte)         ((__pte_page(pte) - PAGE_OFFSET) >> PAGE_SHIFT)
 260
 261 /* permanent address of a page */
 262
 263 #define __page_address(page)    (PAGE_OFFSET + (((page) - mem_map) << PAGE_SHIFT))
 264 #define pte_page(pte)           (mem_map+pte_pagenr(pte))
 265
 266 /* only the pte's themselves need to point to physical DRAM (see above)
 267  * the pagetable links are purely handled within the kernel SW and thus
 268  * don't need the __pa and __va transformations.
 269  */
 270
 271 extern inline void pmd_set(pmd_t * pmdp, pte_t * ptep)
 272 { pmd_val(*pmdp) = _PAGE_TABLE | (unsigned long) ptep; }
 273
 274 #define pmd_page(pmd)           (pfn_to_page(pmd_val(pmd) >> PAGE_SHIFT))
 275 #define pmd_page_kernel(pmd)    ((unsigned long) __va(pmd_val(pmd) & PAGE_MASK))
 276
 277 /* to find an entry in a page-table-directory. */
 278 #define pgd_index(address) ((address >> PGDIR_SHIFT) & (PTRS_PER_PGD-1))
 279
 280 /* to find an entry in a page-table-directory */
 281 extern inline pgd_t * pgd_offset(struct mm_struct * mm, unsigned long address)
 282 {
 283         return mm->pgd + pgd_index(address);
 284 }
 285
 286 /* to find an entry in a kernel page-table-directory */
 287 #define pgd_offset_k(address) pgd_offset(&init_mm, address)
 288
 289 /* Find an entry in the second-level page table.. */
 290 extern inline pmd_t * pmd_offset(pgd_t * dir, unsigned long address)
 291 {
 292         return (pmd_t *) dir;
 293 }
 294
 295 /* Find an entry in the third-level page table.. */
 296 #define __pte_offset(address) \
 297         (((address) >> PAGE_SHIFT) & (PTRS_PER_PTE - 1))
 298 #define pte_offset_kernel(dir, address) \
 299         ((pte_t *) pmd_page_kernel(*(dir)) +  __pte_offset(address))
 300 #define pte_offset_map(dir, address) \
 301         ((pte_t *)page_address(pmd_page(*(dir))) + __pte_offset(address))
 302 #define pte_offset_map_nested(dir, address) pte_offset_map(dir, address)
 303
 304 #define pte_unmap(pte) do { } while (0)
 305 #define pte_unmap_nested(pte) do { } while (0)
 306 #define pte_pfn(x)              ((unsigned long)(__va((x).pte)) >> PAGE_SHIFT)
 307 #define pfn_pte(pfn, prot)      __pte((__pa((pfn) << PAGE_SHIFT)) | pgprot_val(prot))
 308
 309 #define pte_ERROR(e) \
 310         printk("%s:%d: bad pte %p(%08lx).\n", __FILE__, __LINE__, &(e), pte_val(e))
 311 #define pmd_ERROR(e) \
 312         printk("%s:%d: bad pmd %p(%08lx).\n", __FILE__, __LINE__, &(e), pmd_val(e))
 313 #define pgd_ERROR(e) \
 314         printk("%s:%d: bad pgd %p(%08lx).\n", __FILE__, __LINE__, &(e), pgd_val(e))
 315
 316
 317 extern pgd_t swapper_pg_dir[PTRS_PER_PGD]; /* defined in head.S */
 318
 319 /*
 320  * CRIS doesn't have any external MMU info: the kernel page
 321  * tables contain all the necessary information.
 322  *
 323  * Actually I am not sure on what this could be used for.
 324  */
 325 extern inline void update_mmu_cache(struct vm_area_struct * vma,
 326         unsigned long address, pte_t pte)
 327 {
 328 }
 329
 330 /* Encode and de-code a swap entry (must be !pte_none(e) && !pte_present(e)) */
 331 /* Since the PAGE_PRESENT bit is bit 4, we can use the bits above */
 332
 333 #define __swp_type(x)                   (((x).val >> 5) & 0x7f)
 334 #define __swp_offset(x)                 ((x).val >> 12)
 335 #define __swp_entry(type, offset)       ((swp_entry_t) { ((type) << 5) | ((offset) << 12) })
 336 #define __pte_to_swp_entry(pte)         ((swp_entry_t) { pte_val(pte) })
 337 #define __swp_entry_to_pte(x)           ((pte_t) { (x).val })
 338
 339 #define kern_addr_valid(addr)   (1)
 340
 341 #include <asm-generic/pgtable.h>
 342
 343 /*
 344  * No page table caches to initialise
 345  */
 346 #define pgtable_cache_init()   do { } while (0)
 347
 348 #define pte_to_pgoff(x) (pte_val(x) >> 6)
 349 #define pgoff_to_pte(x) __pte(((x) << 6) | _PAGE_FILE)
 350
 351 #endif /* __ASSEMBLY__ */
 352 #endif /* _CRIS_PGTABLE_H */