LXR linux/include/asm-generic/pgtable.h

   1#ifndef _ASM_GENERIC_PGTABLE_H
   2#define _ASM_GENERIC_PGTABLE_H
   3
   4#ifndef __ASSEMBLY__
   5#ifdef CONFIG_MMU
   6
   7#ifndef __HAVE_ARCH_PTEP_SET_ACCESS_FLAGS
   8/*
   9 * Largely same as above, but only sets the access flags (dirty,
  10 * accessed, and writable). Furthermore, we know it always gets set
  11 * to a "more permissive" setting, which allows most architectures
  12 * to optimize this. We return whether the PTE actually changed, which
  13 * in turn instructs the caller to do things like update__mmu_cache.
  14 * This used to be done in the caller, but sparc needs minor faults to
  15 * force that call on sun4c so we changed this macro slightly
  16 */
  17#define ptep_set_access_flags(__vma, __address, __ptep, __entry, __dirty) \
  18({                                                                        \
  19        int __changed = !pte_same(*(__ptep), __entry);                    \
  20        if (__changed) {                                                  \
  21                set_pte_at((__vma)->vm_mm, (__address), __ptep, __entry); \
  22                flush_tlb_page(__vma, __address);                         \
  23        }                                                                 \
  24        __changed;                                                        \
  25})
  26#endif
  27
  28#ifndef __HAVE_ARCH_PTEP_TEST_AND_CLEAR_YOUNG
  29#define ptep_test_and_clear_young(__vma, __address, __ptep)             \
  30({                                                                      \
  31        pte_t __pte = *(__ptep);                                        \
  32        int r = 1;                                                      \
  33        if (!pte_young(__pte))                                          \
  34                r = 0;                                                  \
  35        else                                                            \
  36                set_pte_at((__vma)->vm_mm, (__address),                 \
  37                           (__ptep), pte_mkold(__pte));                 \
  38        r;                                                              \
  39})
  40#endif
  41
  42#ifndef __HAVE_ARCH_PTEP_CLEAR_YOUNG_FLUSH
  43#define ptep_clear_flush_young(__vma, __address, __ptep)                \
  44({                                                                      \
  45        int __young;                                                    \
  46        __young = ptep_test_and_clear_young(__vma, __address, __ptep);  \
  47        if (__young)                                                    \
  48                flush_tlb_page(__vma, __address);                       \
  49        __young;                                                        \
  50})
  51#endif
  52
  53#ifndef __HAVE_ARCH_PTEP_GET_AND_CLEAR
  54#define ptep_get_and_clear(__mm, __address, __ptep)                     \
  55({                                                                      \
  56        pte_t __pte = *(__ptep);                                        \
  57        pte_clear((__mm), (__address), (__ptep));                       \
  58        __pte;                                                          \
  59})
  60#endif
  61
  62#ifndef __HAVE_ARCH_PTEP_GET_AND_CLEAR_FULL
  63#define ptep_get_and_clear_full(__mm, __address, __ptep, __full)        \
  64({                                                                      \
  65        pte_t __pte;                                                    \
  66        __pte = ptep_get_and_clear((__mm), (__address), (__ptep));      \
  67        __pte;                                                          \
  68})
  69#endif
  70
  71/*
  72 * Some architectures may be able to avoid expensive synchronization
  73 * primitives when modifications are made to PTE's which are already
  74 * not present, or in the process of an address space destruction.
  75 */
  76#ifndef __HAVE_ARCH_PTE_CLEAR_NOT_PRESENT_FULL
  77#define pte_clear_not_present_full(__mm, __address, __ptep, __full)     \
  78do {                                                                    \
  79        pte_clear((__mm), (__address), (__ptep));                       \
  80} while (0)
  81#endif
  82
  83#ifndef __HAVE_ARCH_PTEP_CLEAR_FLUSH
  84#define ptep_clear_flush(__vma, __address, __ptep)                      \
  85({                                                                      \
  86        pte_t __pte;                                                    \
  87        __pte = ptep_get_and_clear((__vma)->vm_mm, __address, __ptep);  \
  88        flush_tlb_page(__vma, __address);                               \
  89        __pte;                                                          \
  90})
  91#endif
  92
  93#ifndef __HAVE_ARCH_PTEP_SET_WRPROTECT
  94struct mm_struct;
  95static inline void ptep_set_wrprotect(struct mm_struct *mm, unsigned long address, pte_t *ptep)
  96{
  97        pte_t old_pte = *ptep;
  98        set_pte_at(mm, address, ptep, pte_wrprotect(old_pte));
  99}
 100#endif
 101
 102#ifndef __HAVE_ARCH_PTE_SAME
 103#define pte_same(A,B)   (pte_val(A) == pte_val(B))
 104#endif
 105
 106#ifndef __HAVE_ARCH_PAGE_TEST_DIRTY
 107#define page_test_dirty(page)           (0)
 108#endif
 109
 110#ifndef __HAVE_ARCH_PAGE_CLEAR_DIRTY
 111#define page_clear_dirty(page)          do { } while (0)
 112#endif
 113
 114#ifndef __HAVE_ARCH_PAGE_TEST_DIRTY
 115#define pte_maybe_dirty(pte)            pte_dirty(pte)
 116#else
 117#define pte_maybe_dirty(pte)            (1)
 118#endif
 119
 120#ifndef __HAVE_ARCH_PAGE_TEST_AND_CLEAR_YOUNG
 121#define page_test_and_clear_young(page) (0)
 122#endif
 123
 124#ifndef __HAVE_ARCH_PGD_OFFSET_GATE
 125#define pgd_offset_gate(mm, addr)       pgd_offset(mm, addr)
 126#endif
 127
 128#ifndef __HAVE_ARCH_MOVE_PTE
 129#define move_pte(pte, prot, old_addr, new_addr) (pte)
 130#endif
 131
 132/*
 133 * When walking page tables, get the address of the next boundary,
 134 * or the end address of the range if that comes earlier.  Although no
 135 * vma end wraps to 0, rounded up __boundary may wrap to 0 throughout.
 136 */
 137
 138#define pgd_addr_end(addr, end)                                         \
 139({      unsigned long __boundary = ((addr) + PGDIR_SIZE) & PGDIR_MASK;  \
 140        (__boundary - 1 < (end) - 1)? __boundary: (end);                \
 141})
 142
 143#ifndef pud_addr_end
 144#define pud_addr_end(addr, end)                                         \
 145({      unsigned long __boundary = ((addr) + PUD_SIZE) & PUD_MASK;      \
 146        (__boundary - 1 < (end) - 1)? __boundary: (end);                \
 147})
 148#endif
 149
 150#ifndef pmd_addr_end
 151#define pmd_addr_end(addr, end)                                         \
 152({      unsigned long __boundary = ((addr) + PMD_SIZE) & PMD_MASK;      \
 153        (__boundary - 1 < (end) - 1)? __boundary: (end);                \
 154})
 155#endif
 156
 157/*
 158 * When walking page tables, we usually want to skip any p?d_none entries;
 159 * and any p?d_bad entries - reporting the error before resetting to none.
 160 * Do the tests inline, but report and clear the bad entry in mm/memory.c.
 161 */
 162void pgd_clear_bad(pgd_t *);
 163void pud_clear_bad(pud_t *);
 164void pmd_clear_bad(pmd_t *);
 165
 166static inline int pgd_none_or_clear_bad(pgd_t *pgd)
 167{
 168        if (pgd_none(*pgd))
 169                return 1;
 170        if (unlikely(pgd_bad(*pgd))) {
 171                pgd_clear_bad(pgd);
 172                return 1;
 173        }
 174        return 0;
 175}
 176
 177static inline int pud_none_or_clear_bad(pud_t *pud)
 178{
 179        if (pud_none(*pud))
 180                return 1;
 181        if (unlikely(pud_bad(*pud))) {
 182                pud_clear_bad(pud);
 183                return 1;
 184        }
 185        return 0;
 186}
 187
 188static inline int pmd_none_or_clear_bad(pmd_t *pmd)
 189{
 190        if (pmd_none(*pmd))
 191                return 1;
 192        if (unlikely(pmd_bad(*pmd))) {
 193                pmd_clear_bad(pmd);
 194                return 1;
 195        }
 196        return 0;
 197}
 198#endif /* CONFIG_MMU */
 199
 200/*
 201 * A facility to provide lazy MMU batching.  This allows PTE updates and
 202 * page invalidations to be delayed until a call to leave lazy MMU mode
 203 * is issued.  Some architectures may benefit from doing this, and it is
 204 * beneficial for both shadow and direct mode hypervisors, which may batch
 205 * the PTE updates which happen during this window.  Note that using this
 206 * interface requires that read hazards be removed from the code.  A read
 207 * hazard could result in the direct mode hypervisor case, since the actual
 208 * write to the page tables may not yet have taken place, so reads though
 209 * a raw PTE pointer after it has been modified are not guaranteed to be
 210 * up to date.  This mode can only be entered and left under the protection of
 211 * the page table locks for all page tables which may be modified.  In the UP
 212 * case, this is required so that preemption is disabled, and in the SMP case,
 213 * it must synchronize the delayed page table writes properly on other CPUs.
 214 */
 215#ifndef __HAVE_ARCH_ENTER_LAZY_MMU_MODE
 216#define arch_enter_lazy_mmu_mode()      do {} while (0)
 217#define arch_leave_lazy_mmu_mode()      do {} while (0)
 218#define arch_flush_lazy_mmu_mode()      do {} while (0)
 219#endif
 220
 221/*
 222 * A facility to provide batching of the reload of page tables with the
 223 * actual context switch code for paravirtualized guests.  By convention,
 224 * only one of the lazy modes (CPU, MMU) should be active at any given
 225 * time, entry should never be nested, and entry and exits should always
 226 * be paired.  This is for sanity of maintaining and reasoning about the
 227 * kernel code.
 228 */
 229#ifndef __HAVE_ARCH_ENTER_LAZY_CPU_MODE
 230#define arch_enter_lazy_cpu_mode()      do {} while (0)
 231#define arch_leave_lazy_cpu_mode()      do {} while (0)
 232#define arch_flush_lazy_cpu_mode()      do {} while (0)
 233#endif
 234
 235#endif /* !__ASSEMBLY__ */
 236
 237#endif /* _ASM_GENERIC_PGTABLE_H */
 238