include/asm-ppc64/pgtable.h

   1 #ifndef _PPC64_PGTABLE_H
   2 #define _PPC64_PGTABLE_H
   3
   4 /*
   5  * This file contains the functions and defines necessary to modify and use
   6  * the ppc64 hashed page table.
   7  */
   8
   9 #ifndef __ASSEMBLY__
  10 #include <linux/config.h>
  11 #include <linux/stddef.h>
  12 #include <asm/processor.h>              /* For TASK_SIZE */
  13 #include <asm/mmu.h>
  14 #include <asm/page.h>
  15 #include <asm/tlbflush.h>
  16 #endif /* __ASSEMBLY__ */
  17
  18 #ifdef CONFIG_PPC_64K_PAGES
  19 #include <asm/pgtable-64k.h>
  20 #else
  21 #include <asm/pgtable-4k.h>
  22 #endif
  23
  24 #define FIRST_USER_ADDRESS      0
  25
  26 /*
  27  * Size of EA range mapped by our pagetables.
  28  */
  29 #define PGTABLE_EADDR_SIZE (PTE_INDEX_SIZE + PMD_INDEX_SIZE + \
  30                             PUD_INDEX_SIZE + PGD_INDEX_SIZE + PAGE_SHIFT)
  31 #define PGTABLE_RANGE (1UL << PGTABLE_EADDR_SIZE)
  32
  33 #if TASK_SIZE_USER64 > PGTABLE_RANGE
  34 #error TASK_SIZE_USER64 exceeds pagetable range
  35 #endif
  36
  37 #if TASK_SIZE_USER64 > (1UL << (USER_ESID_BITS + SID_SHIFT))
  38 #error TASK_SIZE_USER64 exceeds user VSID range
  39 #endif
  40
  41 /*
  42  * Define the address range of the vmalloc VM area.
  43  */
  44 #define VMALLOC_START (0xD000000000000000ul)
  45 #define VMALLOC_SIZE  (0x80000000000UL)
  46 #define VMALLOC_END   (VMALLOC_START + VMALLOC_SIZE)
  47
  48 /*
  49  * Common bits in a linux-style PTE.  These match the bits in the
  50  * (hardware-defined) PowerPC PTE as closely as possible. Additional
  51  * bits may be defined in pgtable-*.h
  52  */
  53 #define _PAGE_PRESENT   0x0001 /* software: pte contains a translation */
  54 #define _PAGE_USER      0x0002 /* matches one of the PP bits */
  55 #define _PAGE_FILE      0x0002 /* (!present only) software: pte holds file offset */
  56 #define _PAGE_EXEC      0x0004 /* No execute on POWER4 and newer (we invert) */
  57 #define _PAGE_GUARDED   0x0008
  58 #define _PAGE_COHERENT  0x0010 /* M: enforce memory coherence (SMP systems) */
  59 #define _PAGE_NO_CACHE  0x0020 /* I: cache inhibit */
  60 #define _PAGE_WRITETHRU 0x0040 /* W: cache write-through */
  61 #define _PAGE_DIRTY     0x0080 /* C: page changed */
  62 #define _PAGE_ACCESSED  0x0100 /* R: page referenced */
  63 #define _PAGE_RW        0x0200 /* software: user write access allowed */
  64 #define _PAGE_HASHPTE   0x0400 /* software: pte has an associated HPTE */
  65 #define _PAGE_BUSY      0x0800 /* software: PTE & hash are busy */
  66
  67 #define _PAGE_BASE      (_PAGE_PRESENT | _PAGE_ACCESSED | _PAGE_COHERENT)
  68
  69 #define _PAGE_WRENABLE  (_PAGE_RW | _PAGE_DIRTY)
  70
  71 /* __pgprot defined in asm-ppc64/page.h */
  72 #define PAGE_NONE       __pgprot(_PAGE_PRESENT | _PAGE_ACCESSED)
  73
  74 #define PAGE_SHARED     __pgprot(_PAGE_BASE | _PAGE_RW | _PAGE_USER)
  75 #define PAGE_SHARED_X   __pgprot(_PAGE_BASE | _PAGE_RW | _PAGE_USER | _PAGE_EXEC)
  76 #define PAGE_COPY       __pgprot(_PAGE_BASE | _PAGE_USER)
  77 #define PAGE_COPY_X     __pgprot(_PAGE_BASE | _PAGE_USER | _PAGE_EXEC)
  78 #define PAGE_READONLY   __pgprot(_PAGE_BASE | _PAGE_USER)
  79 #define PAGE_READONLY_X __pgprot(_PAGE_BASE | _PAGE_USER | _PAGE_EXEC)
  80 #define PAGE_KERNEL     __pgprot(_PAGE_BASE | _PAGE_WRENABLE)
  81 #define PAGE_KERNEL_CI  __pgprot(_PAGE_PRESENT | _PAGE_ACCESSED | \
  82                                _PAGE_WRENABLE | _PAGE_NO_CACHE | _PAGE_GUARDED)
  83 #define PAGE_KERNEL_EXEC __pgprot(_PAGE_BASE | _PAGE_WRENABLE | _PAGE_EXEC)
  84
  85 #define PAGE_AGP        __pgprot(_PAGE_BASE | _PAGE_WRENABLE | _PAGE_NO_CACHE)
  86 #define HAVE_PAGE_AGP
  87
  88 /* PTEIDX nibble */
  89 #define _PTEIDX_SECONDARY       0x8
  90 #define _PTEIDX_GROUP_IX        0x7
  91
  92
  93 /*
  94  * POWER4 and newer have per page execute protection, older chips can only
  95  * do this on a segment (256MB) basis.
  96  *
  97  * Also, write permissions imply read permissions.
  98  * This is the closest we can get..
  99  *
 100  * Note due to the way vm flags are laid out, the bits are XWR
 101  */
 102 #define __P000  PAGE_NONE
 103 #define __P001  PAGE_READONLY
 104 #define __P010  PAGE_COPY
 105 #define __P011  PAGE_COPY
 106 #define __P100  PAGE_READONLY_X
 107 #define __P101  PAGE_READONLY_X
 108 #define __P110  PAGE_COPY_X
 109 #define __P111  PAGE_COPY_X
 110
 111 #define __S000  PAGE_NONE
 112 #define __S001  PAGE_READONLY
 113 #define __S010  PAGE_SHARED
 114 #define __S011  PAGE_SHARED
 115 #define __S100  PAGE_READONLY_X
 116 #define __S101  PAGE_READONLY_X
 117 #define __S110  PAGE_SHARED_X
 118 #define __S111  PAGE_SHARED_X
 119
 120 #ifndef __ASSEMBLY__
 121
 122 /*
 123  * ZERO_PAGE is a global shared page that is always zero: used
 124  * for zero-mapped memory areas etc..
 125  */
 126 extern unsigned long empty_zero_page[PAGE_SIZE/sizeof(unsigned long)];
 127 #define ZERO_PAGE(vaddr) (virt_to_page(empty_zero_page))
 128 #endif /* __ASSEMBLY__ */
 129
 130 #ifdef CONFIG_HUGETLB_PAGE
 131
 132 #define HAVE_ARCH_UNMAPPED_AREA
 133 #define HAVE_ARCH_UNMAPPED_AREA_TOPDOWN
 134
 135 #endif
 136
 137 #ifndef __ASSEMBLY__
 138
 139 /*
 140  * Conversion functions: convert a page and protection to a page entry,
 141  * and a page entry and page directory to the page they refer to.
 142  *
 143  * mk_pte takes a (struct page *) as input
 144  */
 145 #define mk_pte(page, pgprot)    pfn_pte(page_to_pfn(page), (pgprot))
 146
 147 static inline pte_t pfn_pte(unsigned long pfn, pgprot_t pgprot)
 148 {
 149         pte_t pte;
 150
 151
 152         pte_val(pte) = (pfn << PTE_RPN_SHIFT) | pgprot_val(pgprot);
 153         return pte;
 154 }
 155
 156 #define pte_modify(_pte, newprot) \
 157   (__pte((pte_val(_pte) & _PAGE_CHG_MASK) | pgprot_val(newprot)))
 158
 159 #define pte_none(pte)           ((pte_val(pte) & ~_PAGE_HPTEFLAGS) == 0)
 160 #define pte_present(pte)        (pte_val(pte) & _PAGE_PRESENT)
 161
 162 /* pte_clear moved to later in this file */
 163
 164 #define pte_pfn(x)              ((unsigned long)((pte_val(x)>>PTE_RPN_SHIFT)))
 165 #define pte_page(x)             pfn_to_page(pte_pfn(x))
 166
 167 #define pmd_set(pmdp, pmdval)   (pmd_val(*(pmdp)) = (pmdval))
 168 #define pmd_none(pmd)           (!pmd_val(pmd))
 169 #define pmd_bad(pmd)            (pmd_val(pmd) == 0)
 170 #define pmd_present(pmd)        (pmd_val(pmd) != 0)
 171 #define pmd_clear(pmdp)         (pmd_val(*(pmdp)) = 0)
 172 #define pmd_page_kernel(pmd)    (pmd_val(pmd) & ~PMD_MASKED_BITS)
 173 #define pmd_page(pmd)           virt_to_page(pmd_page_kernel(pmd))
 174
 175 #define pud_set(pudp, pudval)   (pud_val(*(pudp)) = (pudval))
 176 #define pud_none(pud)           (!pud_val(pud))
 177 #define pud_bad(pud)            ((pud_val(pud)) == 0)
 178 #define pud_present(pud)        (pud_val(pud) != 0)
 179 #define pud_clear(pudp)         (pud_val(*(pudp)) = 0)
 180 #define pud_page(pud)           (pud_val(pud) & ~PUD_MASKED_BITS)
 181
 182 #define pgd_set(pgdp, pudp)     ({pgd_val(*(pgdp)) = (unsigned long)(pudp);})
 183
 184 /*
 185  * Find an entry in a page-table-directory.  We combine the address region
 186  * (the high order N bits) and the pgd portion of the address.
 187  */
 188 /* to avoid overflow in free_pgtables we don't use PTRS_PER_PGD here */
 189 #define pgd_index(address) (((address) >> (PGDIR_SHIFT)) & 0x1ff)
 190
 191 #define pgd_offset(mm, address)  ((mm)->pgd + pgd_index(address))
 192
 193 #define pmd_offset(pudp,addr) \
 194   (((pmd_t *) pud_page(*(pudp))) + (((addr) >> PMD_SHIFT) & (PTRS_PER_PMD - 1)))
 195
 196 #define pte_offset_kernel(dir,addr) \
 197   (((pte_t *) pmd_page_kernel(*(dir))) + (((addr) >> PAGE_SHIFT) & (PTRS_PER_PTE - 1)))
 198
 199 #define pte_offset_map(dir,addr)        pte_offset_kernel((dir), (addr))
 200 #define pte_offset_map_nested(dir,addr) pte_offset_kernel((dir), (addr))
 201 #define pte_unmap(pte)                  do { } while(0)
 202 #define pte_unmap_nested(pte)           do { } while(0)
 203
 204 /* to find an entry in a kernel page-table-directory */
 205 /* This now only contains the vmalloc pages */
 206 #define pgd_offset_k(address) pgd_offset(&init_mm, address)
 207
 208 /*
 209  * The following only work if pte_present() is true.
 210  * Undefined behaviour if not..
 211  */
 212 static inline int pte_read(pte_t pte)  { return pte_val(pte) & _PAGE_USER;}
 213 static inline int pte_write(pte_t pte) { return pte_val(pte) & _PAGE_RW;}
 214 static inline int pte_exec(pte_t pte)  { return pte_val(pte) & _PAGE_EXEC;}
 215 static inline int pte_dirty(pte_t pte) { return pte_val(pte) & _PAGE_DIRTY;}
 216 static inline int pte_young(pte_t pte) { return pte_val(pte) & _PAGE_ACCESSED;}
 217 static inline int pte_file(pte_t pte) { return pte_val(pte) & _PAGE_FILE;}
 218
 219 static inline void pte_uncache(pte_t pte) { pte_val(pte) |= _PAGE_NO_CACHE; }
 220 static inline void pte_cache(pte_t pte)   { pte_val(pte) &= ~_PAGE_NO_CACHE; }
 221
 222 static inline pte_t pte_rdprotect(pte_t pte) {
 223         pte_val(pte) &= ~_PAGE_USER; return pte; }
 224 static inline pte_t pte_exprotect(pte_t pte) {
 225         pte_val(pte) &= ~_PAGE_EXEC; return pte; }
 226 static inline pte_t pte_wrprotect(pte_t pte) {
 227         pte_val(pte) &= ~(_PAGE_RW); return pte; }
 228 static inline pte_t pte_mkclean(pte_t pte) {
 229         pte_val(pte) &= ~(_PAGE_DIRTY); return pte; }
 230 static inline pte_t pte_mkold(pte_t pte) {
 231         pte_val(pte) &= ~_PAGE_ACCESSED; return pte; }
 232 static inline pte_t pte_mkread(pte_t pte) {
 233         pte_val(pte) |= _PAGE_USER; return pte; }
 234 static inline pte_t pte_mkexec(pte_t pte) {
 235         pte_val(pte) |= _PAGE_USER | _PAGE_EXEC; return pte; }
 236 static inline pte_t pte_mkwrite(pte_t pte) {
 237         pte_val(pte) |= _PAGE_RW; return pte; }
 238 static inline pte_t pte_mkdirty(pte_t pte) {
 239         pte_val(pte) |= _PAGE_DIRTY; return pte; }
 240 static inline pte_t pte_mkyoung(pte_t pte) {
 241         pte_val(pte) |= _PAGE_ACCESSED; return pte; }
 242 static inline pte_t pte_mkhuge(pte_t pte) {
 243         return pte; }
 244
 245 /* Atomic PTE updates */
 246 static inline unsigned long pte_update(pte_t *p, unsigned long clr)
 247 {
 248         unsigned long old, tmp;
 249
 250         __asm__ __volatile__(
 251         "1:     ldarx   %0,0,%3         # pte_update\n\
 252         andi.   %1,%0,%6\n\
 253         bne-    1b \n\
 254         andc    %1,%0,%4 \n\
 255         stdcx.  %1,0,%3 \n\
 256         bne-    1b"
 257         : "=&r" (old), "=&r" (tmp), "=m" (*p)
 258         : "r" (p), "r" (clr), "m" (*p), "i" (_PAGE_BUSY)
 259         : "cc" );
 260         return old;
 261 }
 262
 263 /* PTE updating functions, this function puts the PTE in the
 264  * batch, doesn't actually triggers the hash flush immediately,
 265  * you need to call flush_tlb_pending() to do that.
 266  * Pass -1 for "normal" size (4K or 64K)
 267  */
 268 extern void hpte_update(struct mm_struct *mm, unsigned long addr,
 269                         pte_t *ptep, unsigned long pte, int huge);
 270
 271 static inline int __ptep_test_and_clear_young(struct mm_struct *mm,
 272                                               unsigned long addr, pte_t *ptep)
 273 {
 274         unsigned long old;
 275
 276         if ((pte_val(*ptep) & (_PAGE_ACCESSED | _PAGE_HASHPTE)) == 0)
 277                 return 0;
 278         old = pte_update(ptep, _PAGE_ACCESSED);
 279         if (old & _PAGE_HASHPTE) {
 280                 hpte_update(mm, addr, ptep, old, 0);
 281                 flush_tlb_pending();
 282         }
 283         return (old & _PAGE_ACCESSED) != 0;
 284 }
 285 #define __HAVE_ARCH_PTEP_TEST_AND_CLEAR_YOUNG
 286 #define ptep_test_and_clear_young(__vma, __addr, __ptep)                   \
 287 ({                                                                         \
 288         int __r;                                                           \
 289         __r = __ptep_test_and_clear_young((__vma)->vm_mm, __addr, __ptep); \
 290         __r;                                                               \
 291 })
 292
 293 /*
 294  * On RW/DIRTY bit transitions we can avoid flushing the hpte. For the
 295  * moment we always flush but we need to fix hpte_update and test if the
 296  * optimisation is worth it.
 297  */
 298 static inline int __ptep_test_and_clear_dirty(struct mm_struct *mm,
 299                                               unsigned long addr, pte_t *ptep)
 300 {
 301         unsigned long old;
 302
 303         if ((pte_val(*ptep) & _PAGE_DIRTY) == 0)
 304                 return 0;
 305         old = pte_update(ptep, _PAGE_DIRTY);
 306         if (old & _PAGE_HASHPTE)
 307                 hpte_update(mm, addr, ptep, old, 0);
 308         return (old & _PAGE_DIRTY) != 0;
 309 }
 310 #define __HAVE_ARCH_PTEP_TEST_AND_CLEAR_DIRTY
 311 #define ptep_test_and_clear_dirty(__vma, __addr, __ptep)                   \
 312 ({                                                                         \
 313         int __r;                                                           \
 314         __r = __ptep_test_and_clear_dirty((__vma)->vm_mm, __addr, __ptep); \
 315         __r;                                                               \
 316 })
 317
 318 #define __HAVE_ARCH_PTEP_SET_WRPROTECT
 319 static inline void ptep_set_wrprotect(struct mm_struct *mm, unsigned long addr,
 320                                       pte_t *ptep)
 321 {
 322         unsigned long old;
 323
 324         if ((pte_val(*ptep) & _PAGE_RW) == 0)
 325                 return;
 326         old = pte_update(ptep, _PAGE_RW);
 327         if (old & _PAGE_HASHPTE)
 328                 hpte_update(mm, addr, ptep, old, 0);
 329 }
 330
 331 /*
 332  * We currently remove entries from the hashtable regardless of whether
 333  * the entry was young or dirty. The generic routines only flush if the
 334  * entry was young or dirty which is not good enough.
 335  *
 336  * We should be more intelligent about this but for the moment we override
 337  * these functions and force a tlb flush unconditionally
 338  */
 339 #define __HAVE_ARCH_PTEP_CLEAR_YOUNG_FLUSH
 340 #define ptep_clear_flush_young(__vma, __address, __ptep)                \
 341 ({                                                                      \
 342         int __young = __ptep_test_and_clear_young((__vma)->vm_mm, __address, \
 343                                                   __ptep);              \
 344         __young;                                                        \
 345 })
 346
 347 #define __HAVE_ARCH_PTEP_CLEAR_DIRTY_FLUSH
 348 #define ptep_clear_flush_dirty(__vma, __address, __ptep)                \
 349 ({                                                                      \
 350         int __dirty = __ptep_test_and_clear_dirty((__vma)->vm_mm, __address, \
 351                                                   __ptep);              \
 352         flush_tlb_page(__vma, __address);                               \
 353         __dirty;                                                        \
 354 })
 355
 356 #define __HAVE_ARCH_PTEP_GET_AND_CLEAR
 357 static inline pte_t ptep_get_and_clear(struct mm_struct *mm,
 358                                        unsigned long addr, pte_t *ptep)
 359 {
 360         unsigned long old = pte_update(ptep, ~0UL);
 361
 362         if (old & _PAGE_HASHPTE)
 363                 hpte_update(mm, addr, ptep, old, 0);
 364         return __pte(old);
 365 }
 366
 367 static inline void pte_clear(struct mm_struct *mm, unsigned long addr,
 368                              pte_t * ptep)
 369 {
 370         unsigned long old = pte_update(ptep, ~0UL);
 371
 372         if (old & _PAGE_HASHPTE)
 373                 hpte_update(mm, addr, ptep, old, 0);
 374 }
 375
 376 /*
 377  * set_pte stores a linux PTE into the linux page table.
 378  */
 379 static inline void set_pte_at(struct mm_struct *mm, unsigned long addr,
 380                               pte_t *ptep, pte_t pte)
 381 {
 382         if (pte_present(*ptep)) {
 383                 pte_clear(mm, addr, ptep);
 384                 flush_tlb_pending();
 385         }
 386         pte = __pte(pte_val(pte) & ~_PAGE_HPTEFLAGS);
 387
 388 #ifdef CONFIG_PPC_64K_PAGES
 389         if (mmu_virtual_psize != MMU_PAGE_64K)
 390                 pte = __pte(pte_val(pte) | _PAGE_COMBO);
 391 #endif /* CONFIG_PPC_64K_PAGES */
 392
 393         *ptep = pte;
 394 }
 395
 396 /* Set the dirty and/or accessed bits atomically in a linux PTE, this
 397  * function doesn't need to flush the hash entry
 398  */
 399 #define __HAVE_ARCH_PTEP_SET_ACCESS_FLAGS
 400 static inline void __ptep_set_access_flags(pte_t *ptep, pte_t entry, int dirty)
 401 {
 402         unsigned long bits = pte_val(entry) &
 403                 (_PAGE_DIRTY | _PAGE_ACCESSED | _PAGE_RW | _PAGE_EXEC);
 404         unsigned long old, tmp;
 405
 406         __asm__ __volatile__(
 407         "1:     ldarx   %0,0,%4\n\
 408                 andi.   %1,%0,%6\n\
 409                 bne-    1b \n\
 410                 or      %0,%3,%0\n\
 411                 stdcx.  %0,0,%4\n\
 412                 bne-    1b"
 413         :"=&r" (old), "=&r" (tmp), "=m" (*ptep)
 414         :"r" (bits), "r" (ptep), "m" (*ptep), "i" (_PAGE_BUSY)
 415         :"cc");
 416 }
 417 #define  ptep_set_access_flags(__vma, __address, __ptep, __entry, __dirty) \
 418         do {                                                               \
 419                 __ptep_set_access_flags(__ptep, __entry, __dirty);         \
 420                 flush_tlb_page_nohash(__vma, __address);                   \
 421         } while(0)
 422
 423 /*
 424  * Macro to mark a page protection value as "uncacheable".
 425  */
 426 #define pgprot_noncached(prot)  (__pgprot(pgprot_val(prot) | _PAGE_NO_CACHE | _PAGE_GUARDED))
 427
 428 struct file;
 429 extern pgprot_t phys_mem_access_prot(struct file *file, unsigned long pfn,
 430                                      unsigned long size, pgprot_t vma_prot);
 431 #define __HAVE_PHYS_MEM_ACCESS_PROT
 432
 433 #define __HAVE_ARCH_PTE_SAME
 434 #define pte_same(A,B)   (((pte_val(A) ^ pte_val(B)) & ~_PAGE_HPTEFLAGS) == 0)
 435
 436 #define pte_ERROR(e) \
 437         printk("%s:%d: bad pte %08lx.\n", __FILE__, __LINE__, pte_val(e))
 438 #define pmd_ERROR(e) \
 439         printk("%s:%d: bad pmd %08lx.\n", __FILE__, __LINE__, pmd_val(e))
 440 #define pgd_ERROR(e) \
 441         printk("%s:%d: bad pgd %08lx.\n", __FILE__, __LINE__, pgd_val(e))
 442
 443 extern pgd_t swapper_pg_dir[];
 444
 445 extern void paging_init(void);
 446
 447 #ifdef CONFIG_HUGETLB_PAGE
 448 #define hugetlb_free_pgd_range(tlb, addr, end, floor, ceiling) \
 449         free_pgd_range(tlb, addr, end, floor, ceiling)
 450 #endif
 451
 452 /*
 453  * This gets called at the end of handling a page fault, when
 454  * the kernel has put a new PTE into the page table for the process.
 455  * We use it to put a corresponding HPTE into the hash table
 456  * ahead of time, instead of waiting for the inevitable extra
 457  * hash-table miss exception.
 458  */
 459 struct vm_area_struct;
 460 extern void update_mmu_cache(struct vm_area_struct *, unsigned long, pte_t);
 461
 462 /* Encode and de-code a swap entry */
 463 #define __swp_type(entry)       (((entry).val >> 1) & 0x3f)
 464 #define __swp_offset(entry)     ((entry).val >> 8)
 465 #define __swp_entry(type, offset) ((swp_entry_t){((type)<< 1)|((offset)<<8)})
 466 #define __pte_to_swp_entry(pte) ((swp_entry_t){pte_val(pte) >> PTE_RPN_SHIFT})
 467 #define __swp_entry_to_pte(x)   ((pte_t) { (x).val << PTE_RPN_SHIFT })
 468 #define pte_to_pgoff(pte)       (pte_val(pte) >> PTE_RPN_SHIFT)
 469 #define pgoff_to_pte(off)       ((pte_t) {((off) << PTE_RPN_SHIFT)|_PAGE_FILE})
 470 #define PTE_FILE_MAX_BITS       (BITS_PER_LONG - PTE_RPN_SHIFT)
 471
 472 /*
 473  * kern_addr_valid is intended to indicate whether an address is a valid
 474  * kernel address.  Most 32-bit archs define it as always true (like this)
 475  * but most 64-bit archs actually perform a test.  What should we do here?
 476  * The only use is in fs/ncpfs/dir.c
 477  */
 478 #define kern_addr_valid(addr)   (1)
 479
 480 #define io_remap_pfn_range(vma, vaddr, pfn, size, prot)         \
 481                 remap_pfn_range(vma, vaddr, pfn, size, prot)
 482
 483 void pgtable_cache_init(void);
 484
 485 /*
 486  * find_linux_pte returns the address of a linux pte for a given
 487  * effective address and directory.  If not found, it returns zero.
 488  */static inline pte_t *find_linux_pte(pgd_t *pgdir, unsigned long ea)
 489 {
 490         pgd_t *pg;
 491         pud_t *pu;
 492         pmd_t *pm;
 493         pte_t *pt = NULL;
 494
 495         pg = pgdir + pgd_index(ea);
 496         if (!pgd_none(*pg)) {
 497                 pu = pud_offset(pg, ea);
 498                 if (!pud_none(*pu)) {
 499                         pm = pmd_offset(pu, ea);
 500                         if (pmd_present(*pm))
 501                                 pt = pte_offset_kernel(pm, ea);
 502                 }
 503         }
 504         return pt;
 505 }
 506
 507 #include <asm-generic/pgtable.h>
 508
 509 #endif /* __ASSEMBLY__ */
 510
 511 #endif /* _PPC64_PGTABLE_H */