include/asm-alpha/pgtable.h

   1 #ifndef _ALPHA_PGTABLE_H
   2 #define _ALPHA_PGTABLE_H
   3
   4 /*
   5  * This file contains the functions and defines necessary to modify and use
   6  * the Alpha page table tree.
   7  *
   8  * This hopefully works with any standard Alpha page-size, as defined
   9  * in <asm/page.h> (currently 8192).
  10  */
  11 #include <linux/config.h>
  12
  13 #include <asm/page.h>
  14 #include <asm/processor.h>      /* For TASK_SIZE */
  15 #include <asm/machvec.h>
  16
  17 /* Certain architectures need to do special things when PTEs
  18  * within a page table are directly modified.  Thus, the following
  19  * hook is made available.
  20  */
  21 #define set_pte(pteptr, pteval) ((*(pteptr)) = (pteval))
  22
  23 /* PMD_SHIFT determines the size of the area a second-level page table can map */
  24 #define PMD_SHIFT       (PAGE_SHIFT + (PAGE_SHIFT-3))
  25 #define PMD_SIZE        (1UL << PMD_SHIFT)
  26 #define PMD_MASK        (~(PMD_SIZE-1))
  27
  28 /* PGDIR_SHIFT determines what a third-level page table entry can map */
  29 #define PGDIR_SHIFT     (PAGE_SHIFT + 2*(PAGE_SHIFT-3))
  30 #define PGDIR_SIZE      (1UL << PGDIR_SHIFT)
  31 #define PGDIR_MASK      (~(PGDIR_SIZE-1))
  32
  33 /*
  34  * Entries per page directory level:  the Alpha is three-level, with
  35  * all levels having a one-page page table.
  36  *
  37  * The PGD is special:  the last entry is reserved for self-mapping.
  38  */
  39 #define PTRS_PER_PTE    (1UL << (PAGE_SHIFT-3))
  40 #define PTRS_PER_PMD    (1UL << (PAGE_SHIFT-3))
  41 #define PTRS_PER_PGD    ((1UL << (PAGE_SHIFT-3))-1)
  42 #define USER_PTRS_PER_PGD       (TASK_SIZE / PGDIR_SIZE)
  43
  44 /* Number of pointers that fit on a page:  this will go away. */
  45 #define PTRS_PER_PAGE   (1UL << (PAGE_SHIFT-3))
  46
  47 #define VMALLOC_START           0xFFFFFE0000000000
  48 #define VMALLOC_VMADDR(x)       ((unsigned long)(x))
  49 #define VMALLOC_END             (~0UL)
  50
  51 /*
  52  * OSF/1 PAL-code-imposed page table bits
  53  */
  54 #define _PAGE_VALID     0x0001
  55 #define _PAGE_FOR       0x0002  /* used for page protection (fault on read) */
  56 #define _PAGE_FOW       0x0004  /* used for page protection (fault on write) */
  57 #define _PAGE_FOE       0x0008  /* used for page protection (fault on exec) */
  58 #define _PAGE_ASM       0x0010
  59 #define _PAGE_KRE       0x0100  /* xxx - see below on the "accessed" bit */
  60 #define _PAGE_URE       0x0200  /* xxx */
  61 #define _PAGE_KWE       0x1000  /* used to do the dirty bit in software */
  62 #define _PAGE_UWE       0x2000  /* used to do the dirty bit in software */
  63
  64 /* .. and these are ours ... */
  65 #define _PAGE_DIRTY     0x20000
  66 #define _PAGE_ACCESSED  0x40000
  67
  68 /*
  69  * NOTE! The "accessed" bit isn't necessarily exact:  it can be kept exactly
  70  * by software (use the KRE/URE/KWE/UWE bits appropriately), but I'll fake it.
  71  * Under Linux/AXP, the "accessed" bit just means "read", and I'll just use
  72  * the KRE/URE bits to watch for it. That way we don't need to overload the
  73  * KWE/UWE bits with both handling dirty and accessed.
  74  *
  75  * Note that the kernel uses the accessed bit just to check whether to page
  76  * out a page or not, so it doesn't have to be exact anyway.
  77  */
  78
  79 #define __DIRTY_BITS    (_PAGE_DIRTY | _PAGE_KWE | _PAGE_UWE)
  80 #define __ACCESS_BITS   (_PAGE_ACCESSED | _PAGE_KRE | _PAGE_URE)
  81
  82 #define _PFN_MASK       0xFFFFFFFF00000000
  83
  84 #define _PAGE_TABLE     (_PAGE_VALID | __DIRTY_BITS | __ACCESS_BITS)
  85 #define _PAGE_CHG_MASK  (_PFN_MASK | __DIRTY_BITS | __ACCESS_BITS)
  86
  87 /*
  88  * All the normal masks have the "page accessed" bits on, as any time they are used,
  89  * the page is accessed. They are cleared only by the page-out routines
  90  */
  91 #define PAGE_NONE       __pgprot(_PAGE_VALID | __ACCESS_BITS | _PAGE_FOR | _PAGE_FOW | _PAGE_FOE)
  92 #define PAGE_SHARED     __pgprot(_PAGE_VALID | __ACCESS_BITS)
  93 #define PAGE_COPY       __pgprot(_PAGE_VALID | __ACCESS_BITS | _PAGE_FOW)
  94 #define PAGE_READONLY   __pgprot(_PAGE_VALID | __ACCESS_BITS | _PAGE_FOW)
  95 #define PAGE_KERNEL     __pgprot(_PAGE_VALID | _PAGE_ASM | _PAGE_KRE | _PAGE_KWE)
  96
  97 #define _PAGE_NORMAL(x) __pgprot(_PAGE_VALID | __ACCESS_BITS | (x))
  98
  99 #define _PAGE_P(x) _PAGE_NORMAL((x) | (((x) & _PAGE_FOW)?0:_PAGE_FOW))
 100 #define _PAGE_S(x) _PAGE_NORMAL(x)
 101
 102 /*
 103  * The hardware can handle write-only mappings, but as the Alpha
 104  * architecture does byte-wide writes with a read-modify-write
 105  * sequence, it's not practical to have write-without-read privs.
 106  * Thus the "-w- -> rw-" and "-wx -> rwx" mapping here (and in
 107  * arch/alpha/mm/fault.c)
 108  */
 109         /* xwr */
 110 #define __P000  _PAGE_P(_PAGE_FOE | _PAGE_FOW | _PAGE_FOR)
 111 #define __P001  _PAGE_P(_PAGE_FOE | _PAGE_FOW)
 112 #define __P010  _PAGE_P(_PAGE_FOE)
 113 #define __P011  _PAGE_P(_PAGE_FOE)
 114 #define __P100  _PAGE_P(_PAGE_FOW | _PAGE_FOR)
 115 #define __P101  _PAGE_P(_PAGE_FOW)
 116 #define __P110  _PAGE_P(0)
 117 #define __P111  _PAGE_P(0)
 118
 119 #define __S000  _PAGE_S(_PAGE_FOE | _PAGE_FOW | _PAGE_FOR)
 120 #define __S001  _PAGE_S(_PAGE_FOE | _PAGE_FOW)
 121 #define __S010  _PAGE_S(_PAGE_FOE)
 122 #define __S011  _PAGE_S(_PAGE_FOE)
 123 #define __S100  _PAGE_S(_PAGE_FOW | _PAGE_FOR)
 124 #define __S101  _PAGE_S(_PAGE_FOW)
 125 #define __S110  _PAGE_S(0)
 126 #define __S111  _PAGE_S(0)
 127
 128 /*
 129  * BAD_PAGETABLE is used when we need a bogus page-table, while
 130  * BAD_PAGE is used for a bogus page.
 131  *
 132  * ZERO_PAGE is a global shared page that is always zero:  used
 133  * for zero-mapped memory areas etc..
 134  */
 135 extern pte_t __bad_page(void);
 136 extern pmd_t * __bad_pagetable(void);
 137
 138 extern unsigned long __zero_page(void);
 139
 140 #define BAD_PAGETABLE   __bad_pagetable()
 141 #define BAD_PAGE        __bad_page()
 142 #define ZERO_PAGE(vaddr)        (mem_map + MAP_NR(ZERO_PGE))
 143
 144 /* number of bits that fit into a memory pointer */
 145 #define BITS_PER_PTR                    (8*sizeof(unsigned long))
 146
 147 /* to align the pointer to a pointer address */
 148 #define PTR_MASK                        (~(sizeof(void*)-1))
 149
 150 /* sizeof(void*)==1<<SIZEOF_PTR_LOG2 */
 151 #define SIZEOF_PTR_LOG2                 3
 152
 153 /* to find an entry in a page-table */
 154 #define PAGE_PTR(address)               \
 155   ((unsigned long)(address)>>(PAGE_SHIFT-SIZEOF_PTR_LOG2)&PTR_MASK&~PAGE_MASK)
 156
 157 /*
 158  * On certain platforms whose physical address space can overlap KSEG,
 159  * namely EV6 and above, we must re-twiddle the physaddr to restore the
 160  * correct high-order bits.
 161  */
 162
 163 #if defined(CONFIG_ALPHA_GENERIC) && defined(USE_48_BIT_KSEG)
 164 #error "EV6-only feature in a generic kernel"
 165 #endif
 166 #if defined(CONFIG_ALPHA_GENERIC) || \
 167     (defined(CONFIG_ALPHA_EV6) && !defined(USE_48_BIT_KSEG))
 168 #define PHYS_TWIDDLE(phys) \
 169   ((((phys) & 0xc0000000000UL) == 0x40000000000UL) \
 170   ? ((phys) ^= 0xc0000000000UL) : (phys))
 171 #else
 172 #define PHYS_TWIDDLE(phys) (phys)
 173 #endif
 174
 175 /*
 176  * Conversion functions:  convert a page and protection to a page entry,
 177  * and a page entry and page directory to the page they refer to.
 178  */
 179 #define mk_pte(page, pgprot)                                            \
 180 ({                                                                      \
 181         pte_t pte;                                                      \
 182                                                                         \
 183         pte_val(pte) = ((unsigned long)(page - mem_map) << 32) |        \
 184                        pgprot_val(pgprot);                              \
 185         pte;                                                            \
 186 })
 187
 188 extern inline pte_t mk_pte_phys(unsigned long physpage, pgprot_t pgprot)
 189 { pte_t pte; pte_val(pte) = (PHYS_TWIDDLE(physpage) << (32-PAGE_SHIFT)) | pgprot_val(pgprot); return pte; }
 190
 191 extern inline pte_t pte_modify(pte_t pte, pgprot_t newprot)
 192 { pte_val(pte) = (pte_val(pte) & _PAGE_CHG_MASK) | pgprot_val(newprot); return pte; }
 193
 194 extern inline void pmd_set(pmd_t * pmdp, pte_t * ptep)
 195 { pmd_val(*pmdp) = _PAGE_TABLE | ((((unsigned long) ptep) - PAGE_OFFSET) << (32-PAGE_SHIFT)); }
 196
 197 extern inline void pgd_set(pgd_t * pgdp, pmd_t * pmdp)
 198 { pgd_val(*pgdp) = _PAGE_TABLE | ((((unsigned long) pmdp) - PAGE_OFFSET) << (32-PAGE_SHIFT)); }
 199
 200 #define pte_pagenr(x)   ((unsigned long)((pte_val(x) >> 32)))
 201 #define pte_page(x)     (mem_map+pte_pagenr(x))
 202
 203 extern inline unsigned long pmd_page(pmd_t pmd)
 204 { return PAGE_OFFSET + ((pmd_val(pmd) & _PFN_MASK) >> (32-PAGE_SHIFT)); }
 205
 206 extern inline unsigned long pgd_page(pgd_t pgd)
 207 { return PAGE_OFFSET + ((pgd_val(pgd) & _PFN_MASK) >> (32-PAGE_SHIFT)); }
 208
 209 extern inline int pte_none(pte_t pte)           { return !pte_val(pte); }
 210 extern inline int pte_present(pte_t pte)        { return pte_val(pte) & _PAGE_VALID; }
 211 extern inline void pte_clear(pte_t *ptep)       { pte_val(*ptep) = 0; }
 212
 213 extern inline int pmd_none(pmd_t pmd)           { return !pmd_val(pmd); }
 214 extern inline int pmd_bad(pmd_t pmd)            { return (pmd_val(pmd) & ~_PFN_MASK) != _PAGE_TABLE; }
 215 extern inline int pmd_present(pmd_t pmd)        { return pmd_val(pmd) & _PAGE_VALID; }
 216 extern inline void pmd_clear(pmd_t * pmdp)      { pmd_val(*pmdp) = 0; }
 217
 218 extern inline int pgd_none(pgd_t pgd)           { return !pgd_val(pgd); }
 219 extern inline int pgd_bad(pgd_t pgd)            { return (pgd_val(pgd) & ~_PFN_MASK) != _PAGE_TABLE; }
 220 extern inline int pgd_present(pgd_t pgd)        { return pgd_val(pgd) & _PAGE_VALID; }
 221 extern inline void pgd_clear(pgd_t * pgdp)      { pgd_val(*pgdp) = 0; }
 222
 223 #define page_address(page)      ((page)->virtual)
 224
 225 /*
 226  * The following only work if pte_present() is true.
 227  * Undefined behaviour if not..
 228  */
 229 extern inline int pte_read(pte_t pte)           { return !(pte_val(pte) & _PAGE_FOR); }
 230 extern inline int pte_write(pte_t pte)          { return !(pte_val(pte) & _PAGE_FOW); }
 231 extern inline int pte_exec(pte_t pte)           { return !(pte_val(pte) & _PAGE_FOE); }
 232 extern inline int pte_dirty(pte_t pte)          { return pte_val(pte) & _PAGE_DIRTY; }
 233 extern inline int pte_young(pte_t pte)          { return pte_val(pte) & _PAGE_ACCESSED; }
 234
 235 extern inline pte_t pte_wrprotect(pte_t pte)    { pte_val(pte) |= _PAGE_FOW; return pte; }
 236 extern inline pte_t pte_rdprotect(pte_t pte)    { pte_val(pte) |= _PAGE_FOR; return pte; }
 237 extern inline pte_t pte_exprotect(pte_t pte)    { pte_val(pte) |= _PAGE_FOE; return pte; }
 238 extern inline pte_t pte_mkclean(pte_t pte)      { pte_val(pte) &= ~(__DIRTY_BITS); return pte; }
 239 extern inline pte_t pte_mkold(pte_t pte)        { pte_val(pte) &= ~(__ACCESS_BITS); return pte; }
 240 extern inline pte_t pte_mkwrite(pte_t pte)      { pte_val(pte) &= ~_PAGE_FOW; return pte; }
 241 extern inline pte_t pte_mkread(pte_t pte)       { pte_val(pte) &= ~_PAGE_FOR; return pte; }
 242 extern inline pte_t pte_mkexec(pte_t pte)       { pte_val(pte) &= ~_PAGE_FOE; return pte; }
 243 extern inline pte_t pte_mkdirty(pte_t pte)      { pte_val(pte) |= __DIRTY_BITS; return pte; }
 244 extern inline pte_t pte_mkyoung(pte_t pte)      { pte_val(pte) |= __ACCESS_BITS; return pte; }
 245
 246 #define PAGE_DIR_OFFSET(tsk,address) pgd_offset((tsk),(address))
 247
 248 /* to find an entry in a kernel page-table-directory */
 249 #define pgd_offset_k(address) pgd_offset(&init_mm, address)
 250
 251 /* to find an entry in a page-table-directory. */
 252 #define __pgd_offset(address)   ((address >> PGDIR_SHIFT) & (PTRS_PER_PGD-1))
 253 #define pgd_offset(mm, address) ((mm)->pgd+__pgd_offset(address))
 254
 255 /* Find an entry in the second-level page table.. */
 256 extern inline pmd_t * pmd_offset(pgd_t * dir, unsigned long address)
 257 {
 258         return (pmd_t *) pgd_page(*dir) + ((address >> PMD_SHIFT) & (PTRS_PER_PAGE - 1));
 259 }
 260
 261 /* Find an entry in the third-level page table.. */
 262 extern inline pte_t * pte_offset(pmd_t * dir, unsigned long address)
 263 {
 264         return (pte_t *) pmd_page(*dir) + ((address >> PAGE_SHIFT) & (PTRS_PER_PAGE - 1));
 265 }
 266
 267 extern pgd_t swapper_pg_dir[1024];
 268
 269 /*
 270  * The Alpha doesn't have any external MMU info:  the kernel page
 271  * tables contain all the necessary information.
 272  */
 273 extern inline void update_mmu_cache(struct vm_area_struct * vma,
 274         unsigned long address, pte_t pte)
 275 {
 276 }
 277
 278 /*
 279  * Non-present pages:  high 24 bits are offset, next 8 bits type,
 280  * low 32 bits zero.
 281  */
 282 extern inline pte_t mk_swap_pte(unsigned long type, unsigned long offset)
 283 { pte_t pte; pte_val(pte) = (type << 32) | (offset << 40); return pte; }
 284
 285 #define SWP_TYPE(x)                     (((x).val >> 32) & 0xff)
 286 #define SWP_OFFSET(x)                   ((x).val >> 40)
 287 #define SWP_ENTRY(type, offset)         ((swp_entry_t) { pte_val(mk_swap_pte((type),(offset))) })
 288 #define pte_to_swp_entry(pte)           ((swp_entry_t) { pte_val(pte) })
 289 #define swp_entry_to_pte(x)             ((pte_t) { (x).val })
 290
 291 #define module_map      vmalloc
 292 #define module_unmap    vfree
 293
 294 /* Needs to be defined here and not in linux/mm.h, as it is arch dependent */
 295 #define PageSkip(page)          (0)
 296 #define kern_addr_valid(addr)   (1)
 297
 298 #define io_remap_page_range(start, busaddr, size, prot) \
 299         remap_page_range(start, virt_to_phys(__ioremap(busaddr)), size, prot)
 300
 301 #define pte_ERROR(e) \
 302         printk("%s:%d: bad pte %016lx.\n", __FILE__, __LINE__, pte_val(e))
 303 #define pmd_ERROR(e) \
 304         printk("%s:%d: bad pmd %016lx.\n", __FILE__, __LINE__, pmd_val(e))
 305 #define pgd_ERROR(e) \
 306         printk("%s:%d: bad pgd %016lx.\n", __FILE__, __LINE__, pgd_val(e))
 307
 308 #endif /* _ALPHA_PGTABLE_H */