include/asm-generic/pgtable.h

   1 #ifndef _ASM_GENERIC_PGTABLE_H
   2 #define _ASM_GENERIC_PGTABLE_H
   3
   4 #ifndef __ASSEMBLY__
   5
   6 #ifndef __HAVE_ARCH_PTEP_ESTABLISH
   7 /*
   8  * Establish a new mapping:
   9  *  - flush the old one
  10  *  - update the page tables
  11  *  - inform the TLB about the new one
  12  *
  13  * We hold the mm semaphore for reading, and the pte lock.
  14  *
  15  * Note: the old pte is known to not be writable, so we don't need to
  16  * worry about dirty bits etc getting lost.
  17  */
  18 #ifndef __HAVE_ARCH_SET_PTE_ATOMIC
  19 #define ptep_establish(__vma, __address, __ptep, __entry)               \
  20 do {                                                                    \
  21         set_pte_at((__vma)->vm_mm, (__address), __ptep, __entry);       \
  22         flush_tlb_page(__vma, __address);                               \
  23 } while (0)
  24 #else /* __HAVE_ARCH_SET_PTE_ATOMIC */
  25 #define ptep_establish(__vma, __address, __ptep, __entry)               \
  26 do {                                                                    \
  27         set_pte_atomic(__ptep, __entry);                                \
  28         flush_tlb_page(__vma, __address);                               \
  29 } while (0)
  30 #endif /* __HAVE_ARCH_SET_PTE_ATOMIC */
  31 #endif
  32
  33 #ifndef __HAVE_ARCH_PTEP_SET_ACCESS_FLAGS
  34 /*
  35  * Largely same as above, but only sets the access flags (dirty,
  36  * accessed, and writable). Furthermore, we know it always gets set
  37  * to a "more permissive" setting, which allows most architectures
  38  * to optimize this.
  39  */
  40 #define ptep_set_access_flags(__vma, __address, __ptep, __entry, __dirty) \
  41 do {                                                                      \
  42         set_pte_at((__vma)->vm_mm, (__address), __ptep, __entry);         \
  43         flush_tlb_page(__vma, __address);                                 \
  44 } while (0)
  45 #endif
  46
  47 #ifndef __HAVE_ARCH_PTEP_TEST_AND_CLEAR_YOUNG
  48 #define ptep_test_and_clear_young(__vma, __address, __ptep)             \
  49 ({                                                                      \
  50         pte_t __pte = *(__ptep);                                        \
  51         int r = 1;                                                      \
  52         if (!pte_young(__pte))                                          \
  53                 r = 0;                                                  \
  54         else                                                            \
  55                 set_pte_at((__vma)->vm_mm, (__address),                 \
  56                            (__ptep), pte_mkold(__pte));                 \
  57         r;                                                              \
  58 })
  59 #endif
  60
  61 #ifndef __HAVE_ARCH_PTEP_CLEAR_YOUNG_FLUSH
  62 #define ptep_clear_flush_young(__vma, __address, __ptep)                \
  63 ({                                                                      \
  64         int __young;                                                    \
  65         __young = ptep_test_and_clear_young(__vma, __address, __ptep);  \
  66         if (__young)                                                    \
  67                 flush_tlb_page(__vma, __address);                       \
  68         __young;                                                        \
  69 })
  70 #endif
  71
  72 #ifndef __HAVE_ARCH_PTEP_TEST_AND_CLEAR_DIRTY
  73 #define ptep_test_and_clear_dirty(__vma, __address, __ptep)             \
  74 ({                                                                      \
  75         pte_t __pte = *__ptep;                                          \
  76         int r = 1;                                                      \
  77         if (!pte_dirty(__pte))                                          \
  78                 r = 0;                                                  \
  79         else                                                            \
  80                 set_pte_at((__vma)->vm_mm, (__address), (__ptep),       \
  81                            pte_mkclean(__pte));                         \
  82         r;                                                              \
  83 })
  84 #endif
  85
  86 #ifndef __HAVE_ARCH_PTEP_CLEAR_DIRTY_FLUSH
  87 #define ptep_clear_flush_dirty(__vma, __address, __ptep)                \
  88 ({                                                                      \
  89         int __dirty;                                                    \
  90         __dirty = ptep_test_and_clear_dirty(__vma, __address, __ptep);  \
  91         if (__dirty)                                                    \
  92                 flush_tlb_page(__vma, __address);                       \
  93         __dirty;                                                        \
  94 })
  95 #endif
  96
  97 #ifndef __HAVE_ARCH_PTEP_GET_AND_CLEAR
  98 #define ptep_get_and_clear(__mm, __address, __ptep)                     \
  99 ({                                                                      \
 100         pte_t __pte = *(__ptep);                                        \
 101         pte_clear((__mm), (__address), (__ptep));                       \
 102         __pte;                                                          \
 103 })
 104 #endif
 105
 106 #ifndef __HAVE_ARCH_PTEP_GET_AND_CLEAR_FULL
 107 #define ptep_get_and_clear_full(__mm, __address, __ptep, __full)        \
 108 ({                                                                      \
 109         pte_t __pte;                                                    \
 110         __pte = ptep_get_and_clear((__mm), (__address), (__ptep));      \
 111         __pte;                                                          \
 112 })
 113 #endif
 114
 115 /*
 116  * Some architectures may be able to avoid expensive synchronization
 117  * primitives when modifications are made to PTE's which are already
 118  * not present, or in the process of an address space destruction.
 119  */
 120 #ifndef __HAVE_ARCH_PTE_CLEAR_NOT_PRESENT_FULL
 121 #define pte_clear_not_present_full(__mm, __address, __ptep, __full)     \
 122 do {                                                                    \
 123         pte_clear((__mm), (__address), (__ptep));                       \
 124 } while (0)
 125 #endif
 126
 127 #ifndef __HAVE_ARCH_PTEP_CLEAR_FLUSH
 128 #define ptep_clear_flush(__vma, __address, __ptep)                      \
 129 ({                                                                      \
 130         pte_t __pte;                                                    \
 131         __pte = ptep_get_and_clear((__vma)->vm_mm, __address, __ptep);  \
 132         flush_tlb_page(__vma, __address);                               \
 133         __pte;                                                          \
 134 })
 135 #endif
 136
 137 #ifndef __HAVE_ARCH_PTEP_SET_WRPROTECT
 138 struct mm_struct;
 139 static inline void ptep_set_wrprotect(struct mm_struct *mm, unsigned long address, pte_t *ptep)
 140 {
 141         pte_t old_pte = *ptep;
 142         set_pte_at(mm, address, ptep, pte_wrprotect(old_pte));
 143 }
 144 #endif
 145
 146 #ifndef __HAVE_ARCH_PTE_SAME
 147 #define pte_same(A,B)   (pte_val(A) == pte_val(B))
 148 #endif
 149
 150 #ifndef __HAVE_ARCH_PAGE_TEST_AND_CLEAR_DIRTY
 151 #define page_test_and_clear_dirty(page) (0)
 152 #define pte_maybe_dirty(pte)            pte_dirty(pte)
 153 #else
 154 #define pte_maybe_dirty(pte)            (1)
 155 #endif
 156
 157 #ifndef __HAVE_ARCH_PAGE_TEST_AND_CLEAR_YOUNG
 158 #define page_test_and_clear_young(page) (0)
 159 #endif
 160
 161 #ifndef __HAVE_ARCH_PGD_OFFSET_GATE
 162 #define pgd_offset_gate(mm, addr)       pgd_offset(mm, addr)
 163 #endif
 164
 165 #ifndef __HAVE_ARCH_LAZY_MMU_PROT_UPDATE
 166 #define lazy_mmu_prot_update(pte)       do { } while (0)
 167 #endif
 168
 169 #ifndef __HAVE_ARCH_MOVE_PTE
 170 #define move_pte(pte, prot, old_addr, new_addr) (pte)
 171 #endif
 172
 173 /*
 174  * A facility to provide lazy MMU batching.  This allows PTE updates and
 175  * page invalidations to be delayed until a call to leave lazy MMU mode
 176  * is issued.  Some architectures may benefit from doing this, and it is
 177  * beneficial for both shadow and direct mode hypervisors, which may batch
 178  * the PTE updates which happen during this window.  Note that using this
 179  * interface requires that read hazards be removed from the code.  A read
 180  * hazard could result in the direct mode hypervisor case, since the actual
 181  * write to the page tables may not yet have taken place, so reads though
 182  * a raw PTE pointer after it has been modified are not guaranteed to be
 183  * up to date.  This mode can only be entered and left under the protection of
 184  * the page table locks for all page tables which may be modified.  In the UP
 185  * case, this is required so that preemption is disabled, and in the SMP case,
 186  * it must synchronize the delayed page table writes properly on other CPUs.
 187  */
 188 #ifndef __HAVE_ARCH_ENTER_LAZY_MMU_MODE
 189 #define arch_enter_lazy_mmu_mode()      do {} while (0)
 190 #define arch_leave_lazy_mmu_mode()      do {} while (0)
 191 #endif
 192
 193 /*
 194  * When walking page tables, get the address of the next boundary,
 195  * or the end address of the range if that comes earlier.  Although no
 196  * vma end wraps to 0, rounded up __boundary may wrap to 0 throughout.
 197  */
 198
 199 #define pgd_addr_end(addr, end)                                         \
 200 ({      unsigned long __boundary = ((addr) + PGDIR_SIZE) & PGDIR_MASK;  \
 201         (__boundary - 1 < (end) - 1)? __boundary: (end);                \
 202 })
 203
 204 #ifndef pud_addr_end
 205 #define pud_addr_end(addr, end)                                         \
 206 ({      unsigned long __boundary = ((addr) + PUD_SIZE) & PUD_MASK;      \
 207         (__boundary - 1 < (end) - 1)? __boundary: (end);                \
 208 })
 209 #endif
 210
 211 #ifndef pmd_addr_end
 212 #define pmd_addr_end(addr, end)                                         \
 213 ({      unsigned long __boundary = ((addr) + PMD_SIZE) & PMD_MASK;      \
 214         (__boundary - 1 < (end) - 1)? __boundary: (end);                \
 215 })
 216 #endif
 217
 218 /*
 219  * When walking page tables, we usually want to skip any p?d_none entries;
 220  * and any p?d_bad entries - reporting the error before resetting to none.
 221  * Do the tests inline, but report and clear the bad entry in mm/memory.c.
 222  */
 223 void pgd_clear_bad(pgd_t *);
 224 void pud_clear_bad(pud_t *);
 225 void pmd_clear_bad(pmd_t *);
 226
 227 static inline int pgd_none_or_clear_bad(pgd_t *pgd)
 228 {
 229         if (pgd_none(*pgd))
 230                 return 1;
 231         if (unlikely(pgd_bad(*pgd))) {
 232                 pgd_clear_bad(pgd);
 233                 return 1;
 234         }
 235         return 0;
 236 }
 237
 238 static inline int pud_none_or_clear_bad(pud_t *pud)
 239 {
 240         if (pud_none(*pud))
 241                 return 1;
 242         if (unlikely(pud_bad(*pud))) {
 243                 pud_clear_bad(pud);
 244                 return 1;
 245         }
 246         return 0;
 247 }
 248
 249 static inline int pmd_none_or_clear_bad(pmd_t *pmd)
 250 {
 251         if (pmd_none(*pmd))
 252                 return 1;
 253         if (unlikely(pmd_bad(*pmd))) {
 254                 pmd_clear_bad(pmd);
 255                 return 1;
 256         }
 257         return 0;
 258 }
 259 #endif /* !__ASSEMBLY__ */
 260
 261 #endif /* _ASM_GENERIC_PGTABLE_H */