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_GET_AND_CLEAR
  53 #define ptep_get_and_clear(__mm, __address, __ptep)                     \
  54 ({                                                                      \
  55         pte_t __pte = *(__ptep);                                        \
  56         pte_clear((__mm), (__address), (__ptep));                       \
  57         __pte;                                                          \
  58 })
  59 #endif
  60
  61 #ifndef __HAVE_ARCH_PTEP_GET_AND_CLEAR_FULL
  62 #define ptep_get_and_clear_full(__mm, __address, __ptep, __full)        \
  63 ({                                                                      \
  64         pte_t __pte;                                                    \
  65         __pte = ptep_get_and_clear((__mm), (__address), (__ptep));      \
  66         __pte;                                                          \
  67 })
  68 #endif
  69
  70 /*
  71  * Some architectures may be able to avoid expensive synchronization
  72  * primitives when modifications are made to PTE's which are already
  73  * not present, or in the process of an address space destruction.
  74  */
  75 #ifndef __HAVE_ARCH_PTE_CLEAR_NOT_PRESENT_FULL
  76 #define pte_clear_not_present_full(__mm, __address, __ptep, __full)     \
  77 do {                                                                    \
  78         pte_clear((__mm), (__address), (__ptep));                       \
  79 } while (0)
  80 #endif
  81
  82 #ifndef __HAVE_ARCH_PTEP_CLEAR_FLUSH
  83 #define ptep_clear_flush(__vma, __address, __ptep)                      \
  84 ({                                                                      \
  85         pte_t __pte;                                                    \
  86         __pte = ptep_get_and_clear((__vma)->vm_mm, __address, __ptep);  \
  87         flush_tlb_page(__vma, __address);                               \
  88         __pte;                                                          \
  89 })
  90 #endif
  91
  92 #ifndef __HAVE_ARCH_PTEP_SET_WRPROTECT
  93 struct mm_struct;
  94 static inline void ptep_set_wrprotect(struct mm_struct *mm, unsigned long address, pte_t *ptep)
  95 {
  96         pte_t old_pte = *ptep;
  97         set_pte_at(mm, address, ptep, pte_wrprotect(old_pte));
  98 }
  99 #endif
 100
 101 #ifndef __HAVE_ARCH_PTE_SAME
 102 #define pte_same(A,B)   (pte_val(A) == pte_val(B))
 103 #endif
 104
 105 #ifndef __HAVE_ARCH_PAGE_TEST_DIRTY
 106 #define page_test_dirty(page)           (0)
 107 #endif
 108
 109 #ifndef __HAVE_ARCH_PAGE_CLEAR_DIRTY
 110 #define page_clear_dirty(page)          do { } while (0)
 111 #endif
 112
 113 #ifndef __HAVE_ARCH_PAGE_TEST_DIRTY
 114 #define pte_maybe_dirty(pte)            pte_dirty(pte)
 115 #else
 116 #define pte_maybe_dirty(pte)            (1)
 117 #endif
 118
 119 #ifndef __HAVE_ARCH_PAGE_TEST_AND_CLEAR_YOUNG
 120 #define page_test_and_clear_young(page) (0)
 121 #endif
 122
 123 #ifndef __HAVE_ARCH_PGD_OFFSET_GATE
 124 #define pgd_offset_gate(mm, addr)       pgd_offset(mm, addr)
 125 #endif
 126
 127 #ifndef __HAVE_ARCH_LAZY_MMU_PROT_UPDATE
 128 #define lazy_mmu_prot_update(pte)       do { } while (0)
 129 #endif
 130
 131 #ifndef __HAVE_ARCH_MOVE_PTE
 132 #define move_pte(pte, prot, old_addr, new_addr) (pte)
 133 #endif
 134
 135 /*
 136  * A facility to provide lazy MMU batching.  This allows PTE updates and
 137  * page invalidations to be delayed until a call to leave lazy MMU mode
 138  * is issued.  Some architectures may benefit from doing this, and it is
 139  * beneficial for both shadow and direct mode hypervisors, which may batch
 140  * the PTE updates which happen during this window.  Note that using this
 141  * interface requires that read hazards be removed from the code.  A read
 142  * hazard could result in the direct mode hypervisor case, since the actual
 143  * write to the page tables may not yet have taken place, so reads though
 144  * a raw PTE pointer after it has been modified are not guaranteed to be
 145  * up to date.  This mode can only be entered and left under the protection of
 146  * the page table locks for all page tables which may be modified.  In the UP
 147  * case, this is required so that preemption is disabled, and in the SMP case,
 148  * it must synchronize the delayed page table writes properly on other CPUs.
 149  */
 150 #ifndef __HAVE_ARCH_ENTER_LAZY_MMU_MODE
 151 #define arch_enter_lazy_mmu_mode()      do {} while (0)
 152 #define arch_leave_lazy_mmu_mode()      do {} while (0)
 153 #define arch_flush_lazy_mmu_mode()      do {} while (0)
 154 #endif
 155
 156 /*
 157  * A facility to provide batching of the reload of page tables with the
 158  * actual context switch code for paravirtualized guests.  By convention,
 159  * only one of the lazy modes (CPU, MMU) should be active at any given
 160  * time, entry should never be nested, and entry and exits should always
 161  * be paired.  This is for sanity of maintaining and reasoning about the
 162  * kernel code.
 163  */
 164 #ifndef __HAVE_ARCH_ENTER_LAZY_CPU_MODE
 165 #define arch_enter_lazy_cpu_mode()      do {} while (0)
 166 #define arch_leave_lazy_cpu_mode()      do {} while (0)
 167 #define arch_flush_lazy_cpu_mode()      do {} while (0)
 168 #endif
 169
 170 /*
 171  * When walking page tables, get the address of the next boundary,
 172  * or the end address of the range if that comes earlier.  Although no
 173  * vma end wraps to 0, rounded up __boundary may wrap to 0 throughout.
 174  */
 175
 176 #define pgd_addr_end(addr, end)                                         \
 177 ({      unsigned long __boundary = ((addr) + PGDIR_SIZE) & PGDIR_MASK;  \
 178         (__boundary - 1 < (end) - 1)? __boundary: (end);                \
 179 })
 180
 181 #ifndef pud_addr_end
 182 #define pud_addr_end(addr, end)                                         \
 183 ({      unsigned long __boundary = ((addr) + PUD_SIZE) & PUD_MASK;      \
 184         (__boundary - 1 < (end) - 1)? __boundary: (end);                \
 185 })
 186 #endif
 187
 188 #ifndef pmd_addr_end
 189 #define pmd_addr_end(addr, end)                                         \
 190 ({      unsigned long __boundary = ((addr) + PMD_SIZE) & PMD_MASK;      \
 191         (__boundary - 1 < (end) - 1)? __boundary: (end);                \
 192 })
 193 #endif
 194
 195 /*
 196  * When walking page tables, we usually want to skip any p?d_none entries;
 197  * and any p?d_bad entries - reporting the error before resetting to none.
 198  * Do the tests inline, but report and clear the bad entry in mm/memory.c.
 199  */
 200 void pgd_clear_bad(pgd_t *);
 201 void pud_clear_bad(pud_t *);
 202 void pmd_clear_bad(pmd_t *);
 203
 204 static inline int pgd_none_or_clear_bad(pgd_t *pgd)
 205 {
 206         if (pgd_none(*pgd))
 207                 return 1;
 208         if (unlikely(pgd_bad(*pgd))) {
 209                 pgd_clear_bad(pgd);
 210                 return 1;
 211         }
 212         return 0;
 213 }
 214
 215 static inline int pud_none_or_clear_bad(pud_t *pud)
 216 {
 217         if (pud_none(*pud))
 218                 return 1;
 219         if (unlikely(pud_bad(*pud))) {
 220                 pud_clear_bad(pud);
 221                 return 1;
 222         }
 223         return 0;
 224 }
 225
 226 static inline int pmd_none_or_clear_bad(pmd_t *pmd)
 227 {
 228         if (pmd_none(*pmd))
 229                 return 1;
 230         if (unlikely(pmd_bad(*pmd))) {
 231                 pmd_clear_bad(pmd);
 232                 return 1;
 233         }
 234         return 0;
 235 }
 236 #endif /* !__ASSEMBLY__ */
 237
 238 #endif /* _ASM_GENERIC_PGTABLE_H */