aa3f1202a177c149c8a5e3ead072b6352cdabfe1
[linux-2.6.git] / 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 */