include/asm-alpha/pgtable.h

   1 #ifndef _ALPHA_PGTABLE_H
   2 #define _ALPHA_PGTABLE_H
   3
   4 #include <asm-generic/4level-fixup.h>
   5
   6 /*
   7  * This file contains the functions and defines necessary to modify and use
   8  * the Alpha page table tree.
   9  *
  10  * This hopefully works with any standard Alpha page-size, as defined
  11  * in <asm/page.h> (currently 8192).
  12  */
  13 #include <linux/config.h>
  14 #include <linux/mmzone.h>
  15
  16 #include <asm/page.h>
  17 #include <asm/processor.h>      /* For TASK_SIZE */
  18 #include <asm/machvec.h>
  19
  20 /* Certain architectures need to do special things when PTEs
  21  * within a page table are directly modified.  Thus, the following
  22  * hook is made available.
  23  */
  24 #define set_pte(pteptr, pteval) ((*(pteptr)) = (pteval))
  25 #define set_pte_at(mm,addr,ptep,pteval) set_pte(ptep,pteval)
  26
  27 /* PMD_SHIFT determines the size of the area a second-level page table can map */
  28 #define PMD_SHIFT       (PAGE_SHIFT + (PAGE_SHIFT-3))
  29 #define PMD_SIZE        (1UL << PMD_SHIFT)
  30 #define PMD_MASK        (~(PMD_SIZE-1))
  31
  32 /* PGDIR_SHIFT determines what a third-level page table entry can map */
  33 #define PGDIR_SHIFT     (PAGE_SHIFT + 2*(PAGE_SHIFT-3))
  34 #define PGDIR_SIZE      (1UL << PGDIR_SHIFT)
  35 #define PGDIR_MASK      (~(PGDIR_SIZE-1))
  36
  37 /*
  38  * Entries per page directory level:  the Alpha is three-level, with
  39  * all levels having a one-page page table.
  40  */
  41 #define PTRS_PER_PTE    (1UL << (PAGE_SHIFT-3))
  42 #define PTRS_PER_PMD    (1UL << (PAGE_SHIFT-3))
  43 #define PTRS_PER_PGD    (1UL << (PAGE_SHIFT-3))
  44 #define USER_PTRS_PER_PGD       (TASK_SIZE / PGDIR_SIZE)
  45 #define FIRST_USER_ADDRESS      0
  46
  47 /* Number of pointers that fit on a page:  this will go away. */
  48 #define PTRS_PER_PAGE   (1UL << (PAGE_SHIFT-3))
  49
  50 #ifdef CONFIG_ALPHA_LARGE_VMALLOC
  51 #define VMALLOC_START           0xfffffe0000000000
  52 #else
  53 #define VMALLOC_START           (-2*PGDIR_SIZE)
  54 #endif
  55 #define VMALLOC_END             (-PGDIR_SIZE)
  56
  57 /*
  58  * OSF/1 PAL-code-imposed page table bits
  59  */
  60 #define _PAGE_VALID     0x0001
  61 #define _PAGE_FOR       0x0002  /* used for page protection (fault on read) */
  62 #define _PAGE_FOW       0x0004  /* used for page protection (fault on write) */
  63 #define _PAGE_FOE       0x0008  /* used for page protection (fault on exec) */
  64 #define _PAGE_ASM       0x0010
  65 #define _PAGE_KRE       0x0100  /* xxx - see below on the "accessed" bit */
  66 #define _PAGE_URE       0x0200  /* xxx */
  67 #define _PAGE_KWE       0x1000  /* used to do the dirty bit in software */
  68 #define _PAGE_UWE       0x2000  /* used to do the dirty bit in software */
  69
  70 /* .. and these are ours ... */
  71 #define _PAGE_DIRTY     0x20000
  72 #define _PAGE_ACCESSED  0x40000
  73 #define _PAGE_FILE      0x80000 /* set:pagecache, unset:swap */
  74
  75 /*
  76  * NOTE! The "accessed" bit isn't necessarily exact:  it can be kept exactly
  77  * by software (use the KRE/URE/KWE/UWE bits appropriately), but I'll fake it.
  78  * Under Linux/AXP, the "accessed" bit just means "read", and I'll just use
  79  * the KRE/URE bits to watch for it. That way we don't need to overload the
  80  * KWE/UWE bits with both handling dirty and accessed.
  81  *
  82  * Note that the kernel uses the accessed bit just to check whether to page
  83  * out a page or not, so it doesn't have to be exact anyway.
  84  */
  85
  86 #define __DIRTY_BITS    (_PAGE_DIRTY | _PAGE_KWE | _PAGE_UWE)
  87 #define __ACCESS_BITS   (_PAGE_ACCESSED | _PAGE_KRE | _PAGE_URE)
  88
  89 #define _PFN_MASK       0xFFFFFFFF00000000UL
  90
  91 #define _PAGE_TABLE     (_PAGE_VALID | __DIRTY_BITS | __ACCESS_BITS)
  92 #define _PAGE_CHG_MASK  (_PFN_MASK | __DIRTY_BITS | __ACCESS_BITS)
  93
  94 /*
  95  * All the normal masks have the "page accessed" bits on, as any time they are used,
  96  * the page is accessed. They are cleared only by the page-out routines
  97  */
  98 #define PAGE_NONE       __pgprot(_PAGE_VALID | __ACCESS_BITS | _PAGE_FOR | _PAGE_FOW | _PAGE_FOE)
  99 #define PAGE_SHARED     __pgprot(_PAGE_VALID | __ACCESS_BITS)
 100 #define PAGE_COPY       __pgprot(_PAGE_VALID | __ACCESS_BITS | _PAGE_FOW)
 101 #define PAGE_READONLY   __pgprot(_PAGE_VALID | __ACCESS_BITS | _PAGE_FOW)
 102 #define PAGE_KERNEL     __pgprot(_PAGE_VALID | _PAGE_ASM | _PAGE_KRE | _PAGE_KWE)
 103
 104 #define _PAGE_NORMAL(x) __pgprot(_PAGE_VALID | __ACCESS_BITS | (x))
 105
 106 #define _PAGE_P(x) _PAGE_NORMAL((x) | (((x) & _PAGE_FOW)?0:_PAGE_FOW))
 107 #define _PAGE_S(x) _PAGE_NORMAL(x)
 108
 109 /*
 110  * The hardware can handle write-only mappings, but as the Alpha
 111  * architecture does byte-wide writes with a read-modify-write
 112  * sequence, it's not practical to have write-without-read privs.
 113  * Thus the "-w- -> rw-" and "-wx -> rwx" mapping here (and in
 114  * arch/alpha/mm/fault.c)
 115  */
 116         /* xwr */
 117 #define __P000  _PAGE_P(_PAGE_FOE | _PAGE_FOW | _PAGE_FOR)
 118 #define __P001  _PAGE_P(_PAGE_FOE | _PAGE_FOW)
 119 #define __P010  _PAGE_P(_PAGE_FOE)
 120 #define __P011  _PAGE_P(_PAGE_FOE)
 121 #define __P100  _PAGE_P(_PAGE_FOW | _PAGE_FOR)
 122 #define __P101  _PAGE_P(_PAGE_FOW)
 123 #define __P110  _PAGE_P(0)
 124 #define __P111  _PAGE_P(0)
 125
 126 #define __S000  _PAGE_S(_PAGE_FOE | _PAGE_FOW | _PAGE_FOR)
 127 #define __S001  _PAGE_S(_PAGE_FOE | _PAGE_FOW)
 128 #define __S010  _PAGE_S(_PAGE_FOE)
 129 #define __S011  _PAGE_S(_PAGE_FOE)
 130 #define __S100  _PAGE_S(_PAGE_FOW | _PAGE_FOR)
 131 #define __S101  _PAGE_S(_PAGE_FOW)
 132 #define __S110  _PAGE_S(0)
 133 #define __S111  _PAGE_S(0)
 134
 135 /*
 136  * BAD_PAGETABLE is used when we need a bogus page-table, while
 137  * BAD_PAGE is used for a bogus page.
 138  *
 139  * ZERO_PAGE is a global shared page that is always zero:  used
 140  * for zero-mapped memory areas etc..
 141  */
 142 extern pte_t __bad_page(void);
 143 extern pmd_t * __bad_pagetable(void);
 144
 145 extern unsigned long __zero_page(void);
 146
 147 #define BAD_PAGETABLE   __bad_pagetable()
 148 #define BAD_PAGE        __bad_page()
 149 #define ZERO_PAGE(vaddr)        (virt_to_page(ZERO_PGE))
 150
 151 /* number of bits that fit into a memory pointer */
 152 #define BITS_PER_PTR                    (8*sizeof(unsigned long))
 153
 154 /* to align the pointer to a pointer address */
 155 #define PTR_MASK                        (~(sizeof(void*)-1))
 156
 157 /* sizeof(void*)==1<<SIZEOF_PTR_LOG2 */
 158 #define SIZEOF_PTR_LOG2                 3
 159
 160 /* to find an entry in a page-table */
 161 #define PAGE_PTR(address)               \
 162   ((unsigned long)(address)>>(PAGE_SHIFT-SIZEOF_PTR_LOG2)&PTR_MASK&~PAGE_MASK)
 163
 164 /*
 165  * On certain platforms whose physical address space can overlap KSEG,
 166  * namely EV6 and above, we must re-twiddle the physaddr to restore the
 167  * correct high-order bits.
 168  *
 169  * This is extremely confusing until you realize that this is actually
 170  * just working around a userspace bug.  The X server was intending to
 171  * provide the physical address but instead provided the KSEG address.
 172  * Or tried to, except it's not representable.
 173  *
 174  * On Tsunami there's nothing meaningful at 0x40000000000, so this is
 175  * a safe thing to do.  Come the first core logic that does put something
 176  * in this area -- memory or whathaveyou -- then this hack will have
 177  * to go away.  So be prepared!
 178  */
 179
 180 #if defined(CONFIG_ALPHA_GENERIC) && defined(USE_48_BIT_KSEG)
 181 #error "EV6-only feature in a generic kernel"
 182 #endif
 183 #if defined(CONFIG_ALPHA_GENERIC) || \
 184     (defined(CONFIG_ALPHA_EV6) && !defined(USE_48_BIT_KSEG))
 185 #define KSEG_PFN        (0xc0000000000UL >> PAGE_SHIFT)
 186 #define PHYS_TWIDDLE(pfn) \
 187   ((((pfn) & KSEG_PFN) == (0x40000000000UL >> PAGE_SHIFT)) \
 188   ? ((pfn) ^= KSEG_PFN) : (pfn))
 189 #else
 190 #define PHYS_TWIDDLE(pfn) (pfn)
 191 #endif
 192
 193 /*
 194  * Conversion functions:  convert a page and protection to a page entry,
 195  * and a page entry and page directory to the page they refer to.
 196  */
 197 #ifndef CONFIG_DISCONTIGMEM
 198 #define page_to_pa(page)        (((page) - mem_map) << PAGE_SHIFT)
 199
 200 #define pte_pfn(pte)    (pte_val(pte) >> 32)
 201 #define pte_page(pte)   pfn_to_page(pte_pfn(pte))
 202 #define mk_pte(page, pgprot)                                            \
 203 ({                                                                      \
 204         pte_t pte;                                                      \
 205                                                                         \
 206         pte_val(pte) = (page_to_pfn(page) << 32) | pgprot_val(pgprot);  \
 207         pte;                                                            \
 208 })
 209 #endif
 210
 211 extern inline pte_t pfn_pte(unsigned long physpfn, pgprot_t pgprot)
 212 { pte_t pte; pte_val(pte) = (PHYS_TWIDDLE(physpfn) << 32) | pgprot_val(pgprot); return pte; }
 213
 214 extern inline pte_t pte_modify(pte_t pte, pgprot_t newprot)
 215 { pte_val(pte) = (pte_val(pte) & _PAGE_CHG_MASK) | pgprot_val(newprot); return pte; }
 216
 217 extern inline void pmd_set(pmd_t * pmdp, pte_t * ptep)
 218 { pmd_val(*pmdp) = _PAGE_TABLE | ((((unsigned long) ptep) - PAGE_OFFSET) << (32-PAGE_SHIFT)); }
 219
 220 extern inline void pgd_set(pgd_t * pgdp, pmd_t * pmdp)
 221 { pgd_val(*pgdp) = _PAGE_TABLE | ((((unsigned long) pmdp) - PAGE_OFFSET) << (32-PAGE_SHIFT)); }
 222
 223
 224 extern inline unsigned long
 225 pmd_page_kernel(pmd_t pmd)
 226 {
 227         return ((pmd_val(pmd) & _PFN_MASK) >> (32-PAGE_SHIFT)) + PAGE_OFFSET;
 228 }
 229
 230 #ifndef CONFIG_DISCONTIGMEM
 231 #define pmd_page(pmd)   (mem_map + ((pmd_val(pmd) & _PFN_MASK) >> 32))
 232 #endif
 233
 234 extern inline unsigned long pgd_page(pgd_t pgd)
 235 { return PAGE_OFFSET + ((pgd_val(pgd) & _PFN_MASK) >> (32-PAGE_SHIFT)); }
 236
 237 extern inline int pte_none(pte_t pte)           { return !pte_val(pte); }
 238 extern inline int pte_present(pte_t pte)        { return pte_val(pte) & _PAGE_VALID; }
 239 extern inline void pte_clear(struct mm_struct *mm, unsigned long addr, pte_t *ptep)
 240 {
 241         pte_val(*ptep) = 0;
 242 }
 243
 244 extern inline int pmd_none(pmd_t pmd)           { return !pmd_val(pmd); }
 245 extern inline int pmd_bad(pmd_t pmd)            { return (pmd_val(pmd) & ~_PFN_MASK) != _PAGE_TABLE; }
 246 extern inline int pmd_present(pmd_t pmd)        { return pmd_val(pmd) & _PAGE_VALID; }
 247 extern inline void pmd_clear(pmd_t * pmdp)      { pmd_val(*pmdp) = 0; }
 248
 249 extern inline int pgd_none(pgd_t pgd)           { return !pgd_val(pgd); }
 250 extern inline int pgd_bad(pgd_t pgd)            { return (pgd_val(pgd) & ~_PFN_MASK) != _PAGE_TABLE; }
 251 extern inline int pgd_present(pgd_t pgd)        { return pgd_val(pgd) & _PAGE_VALID; }
 252 extern inline void pgd_clear(pgd_t * pgdp)      { pgd_val(*pgdp) = 0; }
 253
 254 /*
 255  * The following only work if pte_present() is true.
 256  * Undefined behaviour if not..
 257  */
 258 extern inline int pte_read(pte_t pte)           { return !(pte_val(pte) & _PAGE_FOR); }
 259 extern inline int pte_write(pte_t pte)          { return !(pte_val(pte) & _PAGE_FOW); }
 260 extern inline int pte_exec(pte_t pte)           { return !(pte_val(pte) & _PAGE_FOE); }
 261 extern inline int pte_dirty(pte_t pte)          { return pte_val(pte) & _PAGE_DIRTY; }
 262 extern inline int pte_young(pte_t pte)          { return pte_val(pte) & _PAGE_ACCESSED; }
 263 extern inline int pte_file(pte_t pte)           { return pte_val(pte) & _PAGE_FILE; }
 264
 265 extern inline pte_t pte_wrprotect(pte_t pte)    { pte_val(pte) |= _PAGE_FOW; return pte; }
 266 extern inline pte_t pte_rdprotect(pte_t pte)    { pte_val(pte) |= _PAGE_FOR; return pte; }
 267 extern inline pte_t pte_exprotect(pte_t pte)    { pte_val(pte) |= _PAGE_FOE; return pte; }
 268 extern inline pte_t pte_mkclean(pte_t pte)      { pte_val(pte) &= ~(__DIRTY_BITS); return pte; }
 269 extern inline pte_t pte_mkold(pte_t pte)        { pte_val(pte) &= ~(__ACCESS_BITS); return pte; }
 270 extern inline pte_t pte_mkwrite(pte_t pte)      { pte_val(pte) &= ~_PAGE_FOW; return pte; }
 271 extern inline pte_t pte_mkread(pte_t pte)       { pte_val(pte) &= ~_PAGE_FOR; return pte; }
 272 extern inline pte_t pte_mkexec(pte_t pte)       { pte_val(pte) &= ~_PAGE_FOE; return pte; }
 273 extern inline pte_t pte_mkdirty(pte_t pte)      { pte_val(pte) |= __DIRTY_BITS; return pte; }
 274 extern inline pte_t pte_mkyoung(pte_t pte)      { pte_val(pte) |= __ACCESS_BITS; return pte; }
 275
 276 #define PAGE_DIR_OFFSET(tsk,address) pgd_offset((tsk),(address))
 277
 278 /* to find an entry in a kernel page-table-directory */
 279 #define pgd_offset_k(address) pgd_offset(&init_mm, (address))
 280
 281 /* to find an entry in a page-table-directory. */
 282 #define pgd_index(address)      (((address) >> PGDIR_SHIFT) & (PTRS_PER_PGD-1))
 283 #define pgd_offset(mm, address) ((mm)->pgd+pgd_index(address))
 284
 285 /* Find an entry in the second-level page table.. */
 286 extern inline pmd_t * pmd_offset(pgd_t * dir, unsigned long address)
 287 {
 288         return (pmd_t *) pgd_page(*dir) + ((address >> PMD_SHIFT) & (PTRS_PER_PAGE - 1));
 289 }
 290
 291 /* Find an entry in the third-level page table.. */
 292 extern inline pte_t * pte_offset_kernel(pmd_t * dir, unsigned long address)
 293 {
 294         return (pte_t *) pmd_page_kernel(*dir)
 295                 + ((address >> PAGE_SHIFT) & (PTRS_PER_PAGE - 1));
 296 }
 297
 298 #define pte_offset_map(dir,addr)        pte_offset_kernel((dir),(addr))
 299 #define pte_offset_map_nested(dir,addr) pte_offset_kernel((dir),(addr))
 300 #define pte_unmap(pte)                  do { } while (0)
 301 #define pte_unmap_nested(pte)           do { } while (0)
 302
 303 extern pgd_t swapper_pg_dir[1024];
 304
 305 /*
 306  * The Alpha doesn't have any external MMU info:  the kernel page
 307  * tables contain all the necessary information.
 308  */
 309 extern inline void update_mmu_cache(struct vm_area_struct * vma,
 310         unsigned long address, pte_t pte)
 311 {
 312 }
 313
 314 /*
 315  * Non-present pages:  high 24 bits are offset, next 8 bits type,
 316  * low 32 bits zero.
 317  */
 318 extern inline pte_t mk_swap_pte(unsigned long type, unsigned long offset)
 319 { pte_t pte; pte_val(pte) = (type << 32) | (offset << 40); return pte; }
 320
 321 #define __swp_type(x)           (((x).val >> 32) & 0xff)
 322 #define __swp_offset(x)         ((x).val >> 40)
 323 #define __swp_entry(type, off)  ((swp_entry_t) { pte_val(mk_swap_pte((type), (off))) })
 324 #define __pte_to_swp_entry(pte) ((swp_entry_t) { pte_val(pte) })
 325 #define __swp_entry_to_pte(x)   ((pte_t) { (x).val })
 326
 327 #define pte_to_pgoff(pte)       (pte_val(pte) >> 32)
 328 #define pgoff_to_pte(off)       ((pte_t) { ((off) << 32) | _PAGE_FILE })
 329
 330 #define PTE_FILE_MAX_BITS       32
 331
 332 #ifndef CONFIG_DISCONTIGMEM
 333 #define kern_addr_valid(addr)   (1)
 334 #endif
 335
 336 #define io_remap_page_range(vma, start, busaddr, size, prot)    \
 337 ({                                                              \
 338         void *va = (void __force *)ioremap(busaddr, size);      \
 339         unsigned long pfn = virt_to_phys(va) >> PAGE_SHIFT;     \
 340         remap_pfn_range(vma, start, pfn, size, prot);           \
 341 })
 342
 343 #define io_remap_pfn_range(vma, start, pfn, size, prot) \
 344                 remap_pfn_range(vma, start, pfn, size, prot)
 345
 346 #define MK_IOSPACE_PFN(space, pfn)      (pfn)
 347 #define GET_IOSPACE(pfn)                0
 348 #define GET_PFN(pfn)                    (pfn)
 349
 350 #define pte_ERROR(e) \
 351         printk("%s:%d: bad pte %016lx.\n", __FILE__, __LINE__, pte_val(e))
 352 #define pmd_ERROR(e) \
 353         printk("%s:%d: bad pmd %016lx.\n", __FILE__, __LINE__, pmd_val(e))
 354 #define pgd_ERROR(e) \
 355         printk("%s:%d: bad pgd %016lx.\n", __FILE__, __LINE__, pgd_val(e))
 356
 357 extern void paging_init(void);
 358
 359 #include <asm-generic/pgtable.h>
 360
 361 /*
 362  * No page table caches to initialise
 363  */
 364 #define pgtable_cache_init()    do { } while (0)
 365
 366 /* We have our own get_unmapped_area to cope with ADDR_LIMIT_32BIT.  */
 367 #define HAVE_ARCH_UNMAPPED_AREA
 368
 369 #endif /* _ALPHA_PGTABLE_H */