arch/cris/include/asm/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/page.h>
   9 #include <asm-generic/pgtable-nopmd.h>
  10
  11 #ifndef __ASSEMBLY__
  12 #include <linux/sched.h>
  13 #include <asm/mmu.h>
  14 #endif
  15 #include <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_pgu(pudptr, pudval) (*(pudptr) = pudval)
  45
  46 /* PGDIR_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 PGDIR_SHIFT     (PAGE_SHIFT + (PAGE_SHIFT-2))
  52 #define PGDIR_SIZE      (1UL << PGDIR_SHIFT)
  53 #define PGDIR_MASK      (~(PGDIR_SIZE-1))
  54
  55 /*
  56  * entries per page directory level: we use a two-level, so
  57  * we don't really have any PMD directory physically.
  58  * pointers are 4 bytes so we can use the page size and
  59  * divide it by 4 (shift by 2).
  60  */
  61 #define PTRS_PER_PTE    (1UL << (PAGE_SHIFT-2))
  62 #define PTRS_PER_PGD    (1UL << (PAGE_SHIFT-2))
  63
  64 /* calculate how many PGD entries a user-level program can use
  65  * the first mappable virtual address is 0
  66  * (TASK_SIZE is the maximum virtual address space)
  67  */
  68
  69 #define USER_PTRS_PER_PGD       (TASK_SIZE/PGDIR_SIZE)
  70 #define FIRST_USER_ADDRESS      0UL
  71
  72 /* zero page used for uninitialized stuff */
  73 #ifndef __ASSEMBLY__
  74 extern unsigned long empty_zero_page;
  75 #define ZERO_PAGE(vaddr) (virt_to_page(empty_zero_page))
  76 #endif
  77
  78 /* number of bits that fit into a memory pointer */
  79 #define BITS_PER_PTR                    (8*sizeof(unsigned long))
  80
  81 /* to align the pointer to a pointer address */
  82 #define PTR_MASK                        (~(sizeof(void*)-1))
  83
  84 /* sizeof(void*)==1<<SIZEOF_PTR_LOG2 */
  85 /* 64-bit machines, beware!  SRB. */
  86 #define SIZEOF_PTR_LOG2                 2
  87
  88 /* to find an entry in a page-table */
  89 #define PAGE_PTR(address) \
  90 ((unsigned long)(address)>>(PAGE_SHIFT-SIZEOF_PTR_LOG2)&PTR_MASK&~PAGE_MASK)
  91
  92 /* to set the page-dir */
  93 #define SET_PAGE_DIR(tsk,pgdir)
  94
  95 #define pte_none(x)     (!pte_val(x))
  96 #define pte_present(x)  (pte_val(x) & _PAGE_PRESENT)
  97 #define pte_clear(mm,addr,xp)   do { pte_val(*(xp)) = 0; } while (0)
  98
  99 #define pmd_none(x)     (!pmd_val(x))
 100 /* by removing the _PAGE_KERNEL bit from the comparison, the same pmd_bad
 101  * works for both _PAGE_TABLE and _KERNPG_TABLE pmd entries.
 102  */
 103 #define pmd_bad(x)      ((pmd_val(x) & (~PAGE_MASK & ~_PAGE_KERNEL)) != _PAGE_TABLE)
 104 #define pmd_present(x)  (pmd_val(x) & _PAGE_PRESENT)
 105 #define pmd_clear(xp)   do { pmd_val(*(xp)) = 0; } while (0)
 106
 107 #ifndef __ASSEMBLY__
 108
 109 /*
 110  * The following only work if pte_present() is true.
 111  * Undefined behaviour if not..
 112  */
 113
 114 static inline int pte_write(pte_t pte)          { return pte_val(pte) & _PAGE_WRITE; }
 115 static inline int pte_dirty(pte_t pte)          { return pte_val(pte) & _PAGE_MODIFIED; }
 116 static inline int pte_young(pte_t pte)          { return pte_val(pte) & _PAGE_ACCESSED; }
 117 static inline int pte_special(pte_t pte)        { return 0; }
 118
 119 static inline pte_t pte_wrprotect(pte_t pte)
 120 {
 121         pte_val(pte) &= ~(_PAGE_WRITE | _PAGE_SILENT_WRITE);
 122         return pte;
 123 }
 124
 125 static inline pte_t pte_mkclean(pte_t pte)
 126 {
 127         pte_val(pte) &= ~(_PAGE_MODIFIED | _PAGE_SILENT_WRITE);
 128         return pte;
 129 }
 130
 131 static inline pte_t pte_mkold(pte_t pte)
 132 {
 133         pte_val(pte) &= ~(_PAGE_ACCESSED | _PAGE_SILENT_READ);
 134         return pte;
 135 }
 136
 137 static inline pte_t pte_mkwrite(pte_t pte)
 138 {
 139         pte_val(pte) |= _PAGE_WRITE;
 140         if (pte_val(pte) & _PAGE_MODIFIED)
 141                 pte_val(pte) |= _PAGE_SILENT_WRITE;
 142         return pte;
 143 }
 144
 145 static inline pte_t pte_mkdirty(pte_t pte)
 146 {
 147         pte_val(pte) |= _PAGE_MODIFIED;
 148         if (pte_val(pte) & _PAGE_WRITE)
 149                 pte_val(pte) |= _PAGE_SILENT_WRITE;
 150         return pte;
 151 }
 152
 153 static inline pte_t pte_mkyoung(pte_t pte)
 154 {
 155         pte_val(pte) |= _PAGE_ACCESSED;
 156         if (pte_val(pte) & _PAGE_READ)
 157         {
 158                 pte_val(pte) |= _PAGE_SILENT_READ;
 159                 if ((pte_val(pte) & (_PAGE_WRITE | _PAGE_MODIFIED)) ==
 160                     (_PAGE_WRITE | _PAGE_MODIFIED))
 161                         pte_val(pte) |= _PAGE_SILENT_WRITE;
 162         }
 163         return pte;
 164 }
 165 static inline pte_t pte_mkspecial(pte_t pte)    { return pte; }
 166
 167 /*
 168  * Conversion functions: convert a page and protection to a page entry,
 169  * and a page entry and page directory to the page they refer to.
 170  */
 171
 172 /* What actually goes as arguments to the various functions is less than
 173  * obvious, but a rule of thumb is that struct page's goes as struct page *,
 174  * really physical DRAM addresses are unsigned long's, and DRAM "virtual"
 175  * addresses (the 0xc0xxxxxx's) goes as void *'s.
 176  */
 177
 178 static inline pte_t __mk_pte(void * page, pgprot_t pgprot)
 179 {
 180         pte_t pte;
 181         /* the PTE needs a physical address */
 182         pte_val(pte) = __pa(page) | pgprot_val(pgprot);
 183         return pte;
 184 }
 185
 186 #define mk_pte(page, pgprot) __mk_pte(page_address(page), (pgprot))
 187
 188 #define mk_pte_phys(physpage, pgprot) \
 189 ({                                                                      \
 190         pte_t __pte;                                                    \
 191                                                                         \
 192         pte_val(__pte) = (physpage) + pgprot_val(pgprot);               \
 193         __pte;                                                          \
 194 })
 195
 196 static inline pte_t pte_modify(pte_t pte, pgprot_t newprot)
 197 { pte_val(pte) = (pte_val(pte) & _PAGE_CHG_MASK) | pgprot_val(newprot); return pte; }
 198
 199 #define pgprot_noncached(prot) __pgprot((pgprot_val(prot) | _PAGE_NO_CACHE))
 200
 201
 202 /* pte_val refers to a page in the 0x4xxxxxxx physical DRAM interval
 203  * __pte_page(pte_val) refers to the "virtual" DRAM interval
 204  * pte_pagenr refers to the page-number counted starting from the virtual DRAM start
 205  */
 206
 207 static inline unsigned long __pte_page(pte_t pte)
 208 {
 209         /* the PTE contains a physical address */
 210         return (unsigned long)__va(pte_val(pte) & PAGE_MASK);
 211 }
 212
 213 #define pte_pagenr(pte)         ((__pte_page(pte) - PAGE_OFFSET) >> PAGE_SHIFT)
 214
 215 /* permanent address of a page */
 216
 217 #define __page_address(page)    (PAGE_OFFSET + (((page) - mem_map) << PAGE_SHIFT))
 218 #define pte_page(pte)           (mem_map+pte_pagenr(pte))
 219
 220 /* only the pte's themselves need to point to physical DRAM (see above)
 221  * the pagetable links are purely handled within the kernel SW and thus
 222  * don't need the __pa and __va transformations.
 223  */
 224
 225 static inline void pmd_set(pmd_t * pmdp, pte_t * ptep)
 226 { pmd_val(*pmdp) = _PAGE_TABLE | (unsigned long) ptep; }
 227
 228 #define pmd_page(pmd)           (pfn_to_page(pmd_val(pmd) >> PAGE_SHIFT))
 229 #define pmd_page_vaddr(pmd)     ((unsigned long) __va(pmd_val(pmd) & PAGE_MASK))
 230
 231 /* to find an entry in a page-table-directory. */
 232 #define pgd_index(address) (((address) >> PGDIR_SHIFT) & (PTRS_PER_PGD-1))
 233
 234 /* to find an entry in a page-table-directory */
 235 static inline pgd_t * pgd_offset(const struct mm_struct *mm, unsigned long address)
 236 {
 237         return mm->pgd + pgd_index(address);
 238 }
 239
 240 /* to find an entry in a kernel page-table-directory */
 241 #define pgd_offset_k(address) pgd_offset(&init_mm, address)
 242
 243 /* Find an entry in the third-level page table.. */
 244 #define __pte_offset(address) \
 245         (((address) >> PAGE_SHIFT) & (PTRS_PER_PTE - 1))
 246 #define pte_offset_kernel(dir, address) \
 247         ((pte_t *) pmd_page_vaddr(*(dir)) +  __pte_offset(address))
 248 #define pte_offset_map(dir, address) \
 249         ((pte_t *)page_address(pmd_page(*(dir))) + __pte_offset(address))
 250
 251 #define pte_unmap(pte) do { } while (0)
 252 #define pte_pfn(x)              ((unsigned long)(__va((x).pte)) >> PAGE_SHIFT)
 253 #define pfn_pte(pfn, prot)      __pte(((pfn) << PAGE_SHIFT) | pgprot_val(prot))
 254
 255 #define pte_ERROR(e) \
 256         printk("%s:%d: bad pte %p(%08lx).\n", __FILE__, __LINE__, &(e), pte_val(e))
 257 #define pgd_ERROR(e) \
 258         printk("%s:%d: bad pgd %p(%08lx).\n", __FILE__, __LINE__, &(e), pgd_val(e))
 259
 260
 261 extern pgd_t swapper_pg_dir[PTRS_PER_PGD]; /* defined in head.S */
 262
 263 /*
 264  * CRIS doesn't have any external MMU info: the kernel page
 265  * tables contain all the necessary information.
 266  *
 267  * Actually I am not sure on what this could be used for.
 268  */
 269 static inline void update_mmu_cache(struct vm_area_struct * vma,
 270         unsigned long address, pte_t *ptep)
 271 {
 272 }
 273
 274 /* Encode and de-code a swap entry (must be !pte_none(e) && !pte_present(e)) */
 275 /* Since the PAGE_PRESENT bit is bit 4, we can use the bits above */
 276
 277 #define __swp_type(x)                   (((x).val >> 5) & 0x7f)
 278 #define __swp_offset(x)                 ((x).val >> 12)
 279 #define __swp_entry(type, offset)       ((swp_entry_t) { ((type) << 5) | ((offset) << 12) })
 280 #define __pte_to_swp_entry(pte)         ((swp_entry_t) { pte_val(pte) })
 281 #define __swp_entry_to_pte(x)           ((pte_t) { (x).val })
 282
 283 #define kern_addr_valid(addr)   (1)
 284
 285 #include <asm-generic/pgtable.h>
 286
 287 /*
 288  * No page table caches to initialise
 289  */
 290 #define pgtable_cache_init()   do { } while (0)
 291
 292 typedef pte_t *pte_addr_t;
 293
 294 #endif /* __ASSEMBLY__ */
 295 #endif /* _CRIS_PGTABLE_H */