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 #define ptep_establish(__vma, __address, __ptep, __entry)               \
  19 do {                                                                    \
  20         set_pte_at((__vma)->vm_mm, (__address), __ptep, __entry);       \
  21         flush_tlb_page(__vma, __address);                               \
  22 } while (0)
  23 #endif
  24
  25 #ifndef __HAVE_ARCH_PTEP_SET_ACCESS_FLAGS
  26 /*
  27  * Largely same as above, but only sets the access flags (dirty,
  28  * accessed, and writable). Furthermore, we know it always gets set
  29  * to a "more permissive" setting, which allows most architectures
  30  * to optimize this.
  31  */
  32 #define ptep_set_access_flags(__vma, __address, __ptep, __entry, __dirty) \
  33 do {                                                                      \
  34         set_pte_at((__vma)->vm_mm, (__address), __ptep, __entry);         \
  35         flush_tlb_page(__vma, __address);                                 \
  36 } while (0)
  37 #endif
  38
  39 #ifndef __HAVE_ARCH_PTEP_TEST_AND_CLEAR_YOUNG
  40 #define ptep_test_and_clear_young(__vma, __address, __ptep)             \
  41 ({                                                                      \
  42         pte_t __pte = *(__ptep);                                        \
  43         int r = 1;                                                      \
  44         if (!pte_young(__pte))                                          \
  45                 r = 0;                                                  \
  46         else                                                            \
  47                 set_pte_at((__vma)->vm_mm, (__address),                 \
  48                            (__ptep), pte_mkold(__pte));                 \
  49         r;                                                              \
  50 })
  51 #endif
  52
  53 #ifndef __HAVE_ARCH_PTEP_CLEAR_YOUNG_FLUSH
  54 #define ptep_clear_flush_young(__vma, __address, __ptep)                \
  55 ({                                                                      \
  56         int __young;                                                    \
  57         __young = ptep_test_and_clear_young(__vma, __address, __ptep);  \
  58         if (__young)                                                    \
  59                 flush_tlb_page(__vma, __address);                       \
  60         __young;                                                        \
  61 })
  62 #endif
  63
  64 #ifndef __HAVE_ARCH_PTEP_TEST_AND_CLEAR_DIRTY
  65 #define ptep_test_and_clear_dirty(__vma, __address, __ptep)             \
  66 ({                                                                      \
  67         pte_t __pte = *__ptep;                                          \
  68         int r = 1;                                                      \
  69         if (!pte_dirty(__pte))                                          \
  70                 r = 0;                                                  \
  71         else                                                            \
  72                 set_pte_at((__vma)->vm_mm, (__address), (__ptep),       \
  73                            pte_mkclean(__pte));                         \
  74         r;                                                              \
  75 })
  76 #endif
  77
  78 #ifndef __HAVE_ARCH_PTEP_CLEAR_DIRTY_FLUSH
  79 #define ptep_clear_flush_dirty(__vma, __address, __ptep)                \
  80 ({                                                                      \
  81         int __dirty;                                                    \
  82         __dirty = ptep_test_and_clear_dirty(__vma, __address, __ptep);  \
  83         if (__dirty)                                                    \
  84                 flush_tlb_page(__vma, __address);                       \
  85         __dirty;                                                        \
  86 })
  87 #endif
  88
  89 #ifndef __HAVE_ARCH_PTEP_GET_AND_CLEAR
  90 #define ptep_get_and_clear(__mm, __address, __ptep)                     \
  91 ({                                                                      \
  92         pte_t __pte = *(__ptep);                                        \
  93         pte_clear((__mm), (__address), (__ptep));                       \
  94         __pte;                                                          \
  95 })
  96 #endif
  97
  98 #ifndef __HAVE_ARCH_PTEP_GET_AND_CLEAR_FULL
  99 #define ptep_get_and_clear_full(__mm, __address, __ptep, __full)        \
 100 ({                                                                      \
 101         pte_t __pte;                                                    \
 102         __pte = ptep_get_and_clear((__mm), (__address), (__ptep));      \
 103         __pte;                                                          \
 104 })
 105 #endif
 106
 107 /*
 108  * Some architectures may be able to avoid expensive synchronization
 109  * primitives when modifications are made to PTE's which are already
 110  * not present, or in the process of an address space destruction.
 111  */
 112 #ifndef __HAVE_ARCH_PTE_CLEAR_NOT_PRESENT_FULL
 113 #define pte_clear_not_present_full(__mm, __address, __ptep, __full)     \
 114 do {                                                                    \
 115         pte_clear((__mm), (__address), (__ptep));                       \
 116 } while (0)
 117 #endif
 118
 119 #ifndef __HAVE_ARCH_PTEP_CLEAR_FLUSH
 120 #define ptep_clear_flush(__vma, __address, __ptep)                      \
 121 ({                                                                      \
 122         pte_t __pte;                                                    \
 123         __pte = ptep_get_and_clear((__vma)->vm_mm, __address, __ptep);  \
 124         flush_tlb_page(__vma, __address);                               \
 125         __pte;                                                          \
 126 })
 127 #endif
 128
 129 #ifndef __HAVE_ARCH_PTEP_SET_WRPROTECT
 130 struct mm_struct;
 131 static inline void ptep_set_wrprotect(struct mm_struct *mm, unsigned long address, pte_t *ptep)
 132 {
 133         pte_t old_pte = *ptep;
 134         set_pte_at(mm, address, ptep, pte_wrprotect(old_pte));
 135 }
 136 #endif
 137
 138 #ifndef __HAVE_ARCH_PTE_SAME
 139 #define pte_same(A,B)   (pte_val(A) == pte_val(B))
 140 #endif
 141
 142 #ifndef __HAVE_ARCH_PAGE_TEST_AND_CLEAR_DIRTY
 143 #define page_test_and_clear_dirty(page) (0)
 144 #define pte_maybe_dirty(pte)            pte_dirty(pte)
 145 #else
 146 #define pte_maybe_dirty(pte)            (1)
 147 #endif
 148
 149 #ifndef __HAVE_ARCH_PAGE_TEST_AND_CLEAR_YOUNG
 150 #define page_test_and_clear_young(page) (0)
 151 #endif
 152
 153 #ifndef __HAVE_ARCH_PGD_OFFSET_GATE
 154 #define pgd_offset_gate(mm, addr)       pgd_offset(mm, addr)
 155 #endif
 156
 157 #ifndef __HAVE_ARCH_LAZY_MMU_PROT_UPDATE
 158 #define lazy_mmu_prot_update(pte)       do { } while (0)
 159 #endif
 160
 161 #ifndef __HAVE_ARCH_MOVE_PTE
 162 #define move_pte(pte, prot, old_addr, new_addr) (pte)
 163 #endif
 164
 165 /*
 166  * A facility to provide lazy MMU batching.  This allows PTE updates and
 167  * page invalidations to be delayed until a call to leave lazy MMU mode
 168  * is issued.  Some architectures may benefit from doing this, and it is
 169  * beneficial for both shadow and direct mode hypervisors, which may batch
 170  * the PTE updates which happen during this window.  Note that using this
 171  * interface requires that read hazards be removed from the code.  A read
 172  * hazard could result in the direct mode hypervisor case, since the actual
 173  * write to the page tables may not yet have taken place, so reads though
 174  * a raw PTE pointer after it has been modified are not guaranteed to be
 175  * up to date.  This mode can only be entered and left under the protection of
 176  * the page table locks for all page tables which may be modified.  In the UP
 177  * case, this is required so that preemption is disabled, and in the SMP case,
 178  * it must synchronize the delayed page table writes properly on other CPUs.
 179  */
 180 #ifndef __HAVE_ARCH_ENTER_LAZY_MMU_MODE
 181 #define arch_enter_lazy_mmu_mode()      do {} while (0)
 182 #define arch_leave_lazy_mmu_mode()      do {} while (0)
 183 #define arch_flush_lazy_mmu_mode()      do {} while (0)
 184 #endif
 185
 186 /*
 187  * A facility to provide batching of the reload of page tables with the
 188  * actual context switch code for paravirtualized guests.  By convention,
 189  * only one of the lazy modes (CPU, MMU) should be active at any given
 190  * time, entry should never be nested, and entry and exits should always
 191  * be paired.  This is for sanity of maintaining and reasoning about the
 192  * kernel code.
 193  */
 194 #ifndef __HAVE_ARCH_ENTER_LAZY_CPU_MODE
 195 #define arch_enter_lazy_cpu_mode()      do {} while (0)
 196 #define arch_leave_lazy_cpu_mode()      do {} while (0)
 197 #define arch_flush_lazy_cpu_mode()      do {} while (0)
 198 #endif
 199
 200 /*
 201  * When walking page tables, get the address of the next boundary,
 202  * or the end address of the range if that comes earlier.  Although no
 203  * vma end wraps to 0, rounded up __boundary may wrap to 0 throughout.
 204  */
 205
 206 #define pgd_addr_end(addr, end)                                         \
 207 ({      unsigned long __boundary = ((addr) + PGDIR_SIZE) & PGDIR_MASK;  \
 208         (__boundary - 1 < (end) - 1)? __boundary: (end);                \
 209 })
 210
 211 #ifndef pud_addr_end
 212 #define pud_addr_end(addr, end)                                         \
 213 ({      unsigned long __boundary = ((addr) + PUD_SIZE) & PUD_MASK;      \
 214         (__boundary - 1 < (end) - 1)? __boundary: (end);                \
 215 })
 216 #endif
 217
 218 #ifndef pmd_addr_end
 219 #define pmd_addr_end(addr, end)                                         \
 220 ({      unsigned long __boundary = ((addr) + PMD_SIZE) & PMD_MASK;      \
 221         (__boundary - 1 < (end) - 1)? __boundary: (end);                \
 222 })
 223 #endif
 224
 225 /*
 226  * When walking page tables, we usually want to skip any p?d_none entries;
 227  * and any p?d_bad entries - reporting the error before resetting to none.
 228  * Do the tests inline, but report and clear the bad entry in mm/memory.c.
 229  */
 230 void pgd_clear_bad(pgd_t *);
 231 void pud_clear_bad(pud_t *);
 232 void pmd_clear_bad(pmd_t *);
 233
 234 static inline int pgd_none_or_clear_bad(pgd_t *pgd)
 235 {
 236         if (pgd_none(*pgd))
 237                 return 1;
 238         if (unlikely(pgd_bad(*pgd))) {
 239                 pgd_clear_bad(pgd);
 240                 return 1;
 241         }
 242         return 0;
 243 }
 244
 245 static inline int pud_none_or_clear_bad(pud_t *pud)
 246 {
 247         if (pud_none(*pud))
 248                 return 1;
 249         if (unlikely(pud_bad(*pud))) {
 250                 pud_clear_bad(pud);
 251                 return 1;
 252         }
 253         return 0;
 254 }
 255
 256 static inline int pmd_none_or_clear_bad(pmd_t *pmd)
 257 {
 258         if (pmd_none(*pmd))
 259                 return 1;
 260         if (unlikely(pmd_bad(*pmd))) {
 261                 pmd_clear_bad(pmd);
 262                 return 1;
 263         }
 264         return 0;
 265 }
 266 #endif /* !__ASSEMBLY__ */
 267
 268 #endif /* _ASM_GENERIC_PGTABLE_H */