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_SET_ACCESS_FLAGS
   7 /*
   8  * Largely same as above, but only sets the access flags (dirty,
   9  * accessed, and writable). Furthermore, we know it always gets set
  10  * to a "more permissive" setting, which allows most architectures
  11  * to optimize this. We return whether the PTE actually changed, which
  12  * in turn instructs the caller to do things like update__mmu_cache.
  13  * This used to be done in the caller, but sparc needs minor faults to
  14  * force that call on sun4c so we changed this macro slightly
  15  */
  16 #define ptep_set_access_flags(__vma, __address, __ptep, __entry, __dirty) \
  17 ({                                                                        \
  18         int __changed = !pte_same(*(__ptep), __entry);                    \
  19         if (__changed) {                                                  \
  20                 set_pte_at((__vma)->vm_mm, (__address), __ptep, __entry); \
  21                 flush_tlb_page(__vma, __address);                         \
  22         }                                                                 \
  23         __changed;                                                        \
  24 })
  25 #endif
  26
  27 #ifndef __HAVE_ARCH_PTEP_TEST_AND_CLEAR_YOUNG
  28 #define ptep_test_and_clear_young(__vma, __address, __ptep)             \
  29 ({                                                                      \
  30         pte_t __pte = *(__ptep);                                        \
  31         int r = 1;                                                      \
  32         if (!pte_young(__pte))                                          \
  33                 r = 0;                                                  \
  34         else                                                            \
  35                 set_pte_at((__vma)->vm_mm, (__address),                 \
  36                            (__ptep), pte_mkold(__pte));                 \
  37         r;                                                              \
  38 })
  39 #endif
  40
  41 #ifndef __HAVE_ARCH_PTEP_CLEAR_YOUNG_FLUSH
  42 #define ptep_clear_flush_young(__vma, __address, __ptep)                \
  43 ({                                                                      \
  44         int __young;                                                    \
  45         __young = ptep_test_and_clear_young(__vma, __address, __ptep);  \
  46         if (__young)                                                    \
  47                 flush_tlb_page(__vma, __address);                       \
  48         __young;                                                        \
  49 })
  50 #endif
  51
  52 #ifndef __HAVE_ARCH_PTEP_TEST_AND_CLEAR_DIRTY
  53 #define ptep_test_and_clear_dirty(__vma, __address, __ptep)             \
  54 ({                                                                      \
  55         pte_t __pte = *__ptep;                                          \
  56         int r = 1;                                                      \
  57         if (!pte_dirty(__pte))                                          \
  58                 r = 0;                                                  \
  59         else                                                            \
  60                 set_pte_at((__vma)->vm_mm, (__address), (__ptep),       \
  61                            pte_mkclean(__pte));                         \
  62         r;                                                              \
  63 })
  64 #endif
  65
  66 #ifndef __HAVE_ARCH_PTEP_CLEAR_DIRTY_FLUSH
  67 #define ptep_clear_flush_dirty(__vma, __address, __ptep)                \
  68 ({                                                                      \
  69         int __dirty;                                                    \
  70         __dirty = ptep_test_and_clear_dirty(__vma, __address, __ptep);  \
  71         if (__dirty)                                                    \
  72                 flush_tlb_page(__vma, __address);                       \
  73         __dirty;                                                        \
  74 })
  75 #endif
  76
  77 #ifndef __HAVE_ARCH_PTEP_GET_AND_CLEAR
  78 #define ptep_get_and_clear(__mm, __address, __ptep)                     \
  79 ({                                                                      \
  80         pte_t __pte = *(__ptep);                                        \
  81         pte_clear((__mm), (__address), (__ptep));                       \
  82         __pte;                                                          \
  83 })
  84 #endif
  85
  86 #ifndef __HAVE_ARCH_PTEP_GET_AND_CLEAR_FULL
  87 #define ptep_get_and_clear_full(__mm, __address, __ptep, __full)        \
  88 ({                                                                      \
  89         pte_t __pte;                                                    \
  90         __pte = ptep_get_and_clear((__mm), (__address), (__ptep));      \
  91         __pte;                                                          \
  92 })
  93 #endif
  94
  95 /*
  96  * Some architectures may be able to avoid expensive synchronization
  97  * primitives when modifications are made to PTE's which are already
  98  * not present, or in the process of an address space destruction.
  99  */
 100 #ifndef __HAVE_ARCH_PTE_CLEAR_NOT_PRESENT_FULL
 101 #define pte_clear_not_present_full(__mm, __address, __ptep, __full)     \
 102 do {                                                                    \
 103         pte_clear((__mm), (__address), (__ptep));                       \
 104 } while (0)
 105 #endif
 106
 107 #ifndef __HAVE_ARCH_PTEP_CLEAR_FLUSH
 108 #define ptep_clear_flush(__vma, __address, __ptep)                      \
 109 ({                                                                      \
 110         pte_t __pte;                                                    \
 111         __pte = ptep_get_and_clear((__vma)->vm_mm, __address, __ptep);  \
 112         flush_tlb_page(__vma, __address);                               \
 113         __pte;                                                          \
 114 })
 115 #endif
 116
 117 #ifndef __HAVE_ARCH_PTEP_SET_WRPROTECT
 118 struct mm_struct;
 119 static inline void ptep_set_wrprotect(struct mm_struct *mm, unsigned long address, pte_t *ptep)
 120 {
 121         pte_t old_pte = *ptep;
 122         set_pte_at(mm, address, ptep, pte_wrprotect(old_pte));
 123 }
 124 #endif
 125
 126 #ifndef __HAVE_ARCH_PTE_SAME
 127 #define pte_same(A,B)   (pte_val(A) == pte_val(B))
 128 #endif
 129
 130 #ifndef __HAVE_ARCH_PAGE_TEST_DIRTY
 131 #define page_test_dirty(page)           (0)
 132 #endif
 133
 134 #ifndef __HAVE_ARCH_PAGE_CLEAR_DIRTY
 135 #define page_clear_dirty(page)          do { } while (0)
 136 #endif
 137
 138 #ifndef __HAVE_ARCH_PAGE_TEST_DIRTY
 139 #define pte_maybe_dirty(pte)            pte_dirty(pte)
 140 #else
 141 #define pte_maybe_dirty(pte)            (1)
 142 #endif
 143
 144 #ifndef __HAVE_ARCH_PAGE_TEST_AND_CLEAR_YOUNG
 145 #define page_test_and_clear_young(page) (0)
 146 #endif
 147
 148 #ifndef __HAVE_ARCH_PGD_OFFSET_GATE
 149 #define pgd_offset_gate(mm, addr)       pgd_offset(mm, addr)
 150 #endif
 151
 152 #ifndef __HAVE_ARCH_LAZY_MMU_PROT_UPDATE
 153 #define lazy_mmu_prot_update(pte)       do { } while (0)
 154 #endif
 155
 156 #ifndef __HAVE_ARCH_MOVE_PTE
 157 #define move_pte(pte, prot, old_addr, new_addr) (pte)
 158 #endif
 159
 160 /*
 161  * A facility to provide lazy MMU batching.  This allows PTE updates and
 162  * page invalidations to be delayed until a call to leave lazy MMU mode
 163  * is issued.  Some architectures may benefit from doing this, and it is
 164  * beneficial for both shadow and direct mode hypervisors, which may batch
 165  * the PTE updates which happen during this window.  Note that using this
 166  * interface requires that read hazards be removed from the code.  A read
 167  * hazard could result in the direct mode hypervisor case, since the actual
 168  * write to the page tables may not yet have taken place, so reads though
 169  * a raw PTE pointer after it has been modified are not guaranteed to be
 170  * up to date.  This mode can only be entered and left under the protection of
 171  * the page table locks for all page tables which may be modified.  In the UP
 172  * case, this is required so that preemption is disabled, and in the SMP case,
 173  * it must synchronize the delayed page table writes properly on other CPUs.
 174  */
 175 #ifndef __HAVE_ARCH_ENTER_LAZY_MMU_MODE
 176 #define arch_enter_lazy_mmu_mode()      do {} while (0)
 177 #define arch_leave_lazy_mmu_mode()      do {} while (0)
 178 #define arch_flush_lazy_mmu_mode()      do {} while (0)
 179 #endif
 180
 181 /*
 182  * A facility to provide batching of the reload of page tables with the
 183  * actual context switch code for paravirtualized guests.  By convention,
 184  * only one of the lazy modes (CPU, MMU) should be active at any given
 185  * time, entry should never be nested, and entry and exits should always
 186  * be paired.  This is for sanity of maintaining and reasoning about the
 187  * kernel code.
 188  */
 189 #ifndef __HAVE_ARCH_ENTER_LAZY_CPU_MODE
 190 #define arch_enter_lazy_cpu_mode()      do {} while (0)
 191 #define arch_leave_lazy_cpu_mode()      do {} while (0)
 192 #define arch_flush_lazy_cpu_mode()      do {} while (0)
 193 #endif
 194
 195 /*
 196  * When walking page tables, get the address of the next boundary,
 197  * or the end address of the range if that comes earlier.  Although no
 198  * vma end wraps to 0, rounded up __boundary may wrap to 0 throughout.
 199  */
 200
 201 #define pgd_addr_end(addr, end)                                         \
 202 ({      unsigned long __boundary = ((addr) + PGDIR_SIZE) & PGDIR_MASK;  \
 203         (__boundary - 1 < (end) - 1)? __boundary: (end);                \
 204 })
 205
 206 #ifndef pud_addr_end
 207 #define pud_addr_end(addr, end)                                         \
 208 ({      unsigned long __boundary = ((addr) + PUD_SIZE) & PUD_MASK;      \
 209         (__boundary - 1 < (end) - 1)? __boundary: (end);                \
 210 })
 211 #endif
 212
 213 #ifndef pmd_addr_end
 214 #define pmd_addr_end(addr, end)                                         \
 215 ({      unsigned long __boundary = ((addr) + PMD_SIZE) & PMD_MASK;      \
 216         (__boundary - 1 < (end) - 1)? __boundary: (end);                \
 217 })
 218 #endif
 219
 220 /*
 221  * When walking page tables, we usually want to skip any p?d_none entries;
 222  * and any p?d_bad entries - reporting the error before resetting to none.
 223  * Do the tests inline, but report and clear the bad entry in mm/memory.c.
 224  */
 225 void pgd_clear_bad(pgd_t *);
 226 void pud_clear_bad(pud_t *);
 227 void pmd_clear_bad(pmd_t *);
 228
 229 static inline int pgd_none_or_clear_bad(pgd_t *pgd)
 230 {
 231         if (pgd_none(*pgd))
 232                 return 1;
 233         if (unlikely(pgd_bad(*pgd))) {
 234                 pgd_clear_bad(pgd);
 235                 return 1;
 236         }
 237         return 0;
 238 }
 239
 240 static inline int pud_none_or_clear_bad(pud_t *pud)
 241 {
 242         if (pud_none(*pud))
 243                 return 1;
 244         if (unlikely(pud_bad(*pud))) {
 245                 pud_clear_bad(pud);
 246                 return 1;
 247         }
 248         return 0;
 249 }
 250
 251 static inline int pmd_none_or_clear_bad(pmd_t *pmd)
 252 {
 253         if (pmd_none(*pmd))
 254                 return 1;
 255         if (unlikely(pmd_bad(*pmd))) {
 256                 pmd_clear_bad(pmd);
 257                 return 1;
 258         }
 259         return 0;
 260 }
 261 #endif /* !__ASSEMBLY__ */
 262
 263 #endif /* _ASM_GENERIC_PGTABLE_H */