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Andrea Arcangelicddb8a52008-07-28 15:46:29 -07001#ifndef _LINUX_MMU_NOTIFIER_H
2#define _LINUX_MMU_NOTIFIER_H
3
4#include <linux/list.h>
5#include <linux/spinlock.h>
6#include <linux/mm_types.h>
Sagi Grimberg21a92732012-10-08 16:29:24 -07007#include <linux/srcu.h>
Andrea Arcangelicddb8a52008-07-28 15:46:29 -07008
9struct mmu_notifier;
10struct mmu_notifier_ops;
11
12#ifdef CONFIG_MMU_NOTIFIER
13
14/*
15 * The mmu notifier_mm structure is allocated and installed in
16 * mm->mmu_notifier_mm inside the mm_take_all_locks() protected
17 * critical section and it's released only when mm_count reaches zero
18 * in mmdrop().
19 */
20struct mmu_notifier_mm {
21 /* all mmu notifiers registerd in this mm are queued in this list */
22 struct hlist_head list;
23 /* to serialize the list modifications and hlist_unhashed */
24 spinlock_t lock;
25};
26
27struct mmu_notifier_ops {
28 /*
29 * Called either by mmu_notifier_unregister or when the mm is
30 * being destroyed by exit_mmap, always before all pages are
31 * freed. This can run concurrently with other mmu notifier
32 * methods (the ones invoked outside the mm context) and it
33 * should tear down all secondary mmu mappings and freeze the
34 * secondary mmu. If this method isn't implemented you've to
35 * be sure that nothing could possibly write to the pages
36 * through the secondary mmu by the time the last thread with
37 * tsk->mm == mm exits.
38 *
39 * As side note: the pages freed after ->release returns could
40 * be immediately reallocated by the gart at an alias physical
41 * address with a different cache model, so if ->release isn't
42 * implemented because all _software_ driven memory accesses
43 * through the secondary mmu are terminated by the time the
44 * last thread of this mm quits, you've also to be sure that
45 * speculative _hardware_ operations can't allocate dirty
46 * cachelines in the cpu that could not be snooped and made
47 * coherent with the other read and write operations happening
48 * through the gart alias address, so leading to memory
49 * corruption.
50 */
51 void (*release)(struct mmu_notifier *mn,
52 struct mm_struct *mm);
53
54 /*
55 * clear_flush_young is called after the VM is
56 * test-and-clearing the young/accessed bitflag in the
57 * pte. This way the VM will provide proper aging to the
58 * accesses to the page through the secondary MMUs and not
59 * only to the ones through the Linux pte.
Andres Lagar-Cavilla57128462014-09-22 14:54:42 -070060 * Start-end is necessary in case the secondary MMU is mapping the page
61 * at a smaller granularity than the primary MMU.
Andrea Arcangelicddb8a52008-07-28 15:46:29 -070062 */
63 int (*clear_flush_young)(struct mmu_notifier *mn,
64 struct mm_struct *mm,
Andres Lagar-Cavilla57128462014-09-22 14:54:42 -070065 unsigned long start,
66 unsigned long end);
Andrea Arcangelicddb8a52008-07-28 15:46:29 -070067
68 /*
Andrea Arcangeli8ee53822011-01-13 15:47:10 -080069 * test_young is called to check the young/accessed bitflag in
70 * the secondary pte. This is used to know if the page is
71 * frequently used without actually clearing the flag or tearing
72 * down the secondary mapping on the page.
73 */
74 int (*test_young)(struct mmu_notifier *mn,
75 struct mm_struct *mm,
76 unsigned long address);
77
78 /*
Izik Eidus828502d2009-09-21 17:01:51 -070079 * change_pte is called in cases that pte mapping to page is changed:
80 * for example, when ksm remaps pte to point to a new shared page.
81 */
82 void (*change_pte)(struct mmu_notifier *mn,
83 struct mm_struct *mm,
84 unsigned long address,
85 pte_t pte);
86
87 /*
Andrea Arcangelicddb8a52008-07-28 15:46:29 -070088 * Before this is invoked any secondary MMU is still ok to
89 * read/write to the page previously pointed to by the Linux
90 * pte because the page hasn't been freed yet and it won't be
91 * freed until this returns. If required set_page_dirty has to
92 * be called internally to this method.
93 */
94 void (*invalidate_page)(struct mmu_notifier *mn,
95 struct mm_struct *mm,
96 unsigned long address);
97
98 /*
99 * invalidate_range_start() and invalidate_range_end() must be
100 * paired and are called only when the mmap_sem and/or the
Joerg Roedel0f0a3272014-11-13 13:46:09 +1100101 * locks protecting the reverse maps are held. If the subsystem
102 * can't guarantee that no additional references are taken to
103 * the pages in the range, it has to implement the
104 * invalidate_range() notifier to remove any references taken
105 * after invalidate_range_start().
Andrea Arcangelicddb8a52008-07-28 15:46:29 -0700106 *
107 * Invalidation of multiple concurrent ranges may be
108 * optionally permitted by the driver. Either way the
109 * establishment of sptes is forbidden in the range passed to
110 * invalidate_range_begin/end for the whole duration of the
111 * invalidate_range_begin/end critical section.
112 *
113 * invalidate_range_start() is called when all pages in the
114 * range are still mapped and have at least a refcount of one.
115 *
116 * invalidate_range_end() is called when all pages in the
117 * range have been unmapped and the pages have been freed by
118 * the VM.
119 *
120 * The VM will remove the page table entries and potentially
121 * the page between invalidate_range_start() and
122 * invalidate_range_end(). If the page must not be freed
123 * because of pending I/O or other circumstances then the
124 * invalidate_range_start() callback (or the initial mapping
125 * by the driver) must make sure that the refcount is kept
126 * elevated.
127 *
128 * If the driver increases the refcount when the pages are
129 * initially mapped into an address space then either
130 * invalidate_range_start() or invalidate_range_end() may
131 * decrease the refcount. If the refcount is decreased on
132 * invalidate_range_start() then the VM can free pages as page
133 * table entries are removed. If the refcount is only
134 * droppped on invalidate_range_end() then the driver itself
135 * will drop the last refcount but it must take care to flush
136 * any secondary tlb before doing the final free on the
137 * page. Pages will no longer be referenced by the linux
138 * address space but may still be referenced by sptes until
139 * the last refcount is dropped.
140 */
141 void (*invalidate_range_start)(struct mmu_notifier *mn,
142 struct mm_struct *mm,
143 unsigned long start, unsigned long end);
144 void (*invalidate_range_end)(struct mmu_notifier *mn,
145 struct mm_struct *mm,
146 unsigned long start, unsigned long end);
Joerg Roedel0f0a3272014-11-13 13:46:09 +1100147
148 /*
149 * invalidate_range() is either called between
150 * invalidate_range_start() and invalidate_range_end() when the
151 * VM has to free pages that where unmapped, but before the
152 * pages are actually freed, or outside of _start()/_end() when
153 * a (remote) TLB is necessary.
154 *
155 * If invalidate_range() is used to manage a non-CPU TLB with
156 * shared page-tables, it not necessary to implement the
157 * invalidate_range_start()/end() notifiers, as
158 * invalidate_range() alread catches the points in time when an
159 * external TLB range needs to be flushed.
160 *
161 * The invalidate_range() function is called under the ptl
162 * spin-lock and not allowed to sleep.
163 *
164 * Note that this function might be called with just a sub-range
165 * of what was passed to invalidate_range_start()/end(), if
166 * called between those functions.
167 */
168 void (*invalidate_range)(struct mmu_notifier *mn, struct mm_struct *mm,
169 unsigned long start, unsigned long end);
Andrea Arcangelicddb8a52008-07-28 15:46:29 -0700170};
171
172/*
173 * The notifier chains are protected by mmap_sem and/or the reverse map
174 * semaphores. Notifier chains are only changed when all reverse maps and
175 * the mmap_sem locks are taken.
176 *
177 * Therefore notifier chains can only be traversed when either
178 *
179 * 1. mmap_sem is held.
Davidlohr Buesoc8c06ef2014-12-12 16:54:24 -0800180 * 2. One of the reverse map locks is held (i_mmap_rwsem or anon_vma->rwsem).
Andrea Arcangelicddb8a52008-07-28 15:46:29 -0700181 * 3. No other concurrent thread can access the list (release)
182 */
183struct mmu_notifier {
184 struct hlist_node hlist;
185 const struct mmu_notifier_ops *ops;
186};
187
188static inline int mm_has_notifiers(struct mm_struct *mm)
189{
190 return unlikely(mm->mmu_notifier_mm);
191}
192
193extern int mmu_notifier_register(struct mmu_notifier *mn,
194 struct mm_struct *mm);
195extern int __mmu_notifier_register(struct mmu_notifier *mn,
196 struct mm_struct *mm);
197extern void mmu_notifier_unregister(struct mmu_notifier *mn,
198 struct mm_struct *mm);
Peter Zijlstrab9722162014-08-06 16:08:20 -0700199extern void mmu_notifier_unregister_no_release(struct mmu_notifier *mn,
200 struct mm_struct *mm);
Andrea Arcangelicddb8a52008-07-28 15:46:29 -0700201extern void __mmu_notifier_mm_destroy(struct mm_struct *mm);
202extern void __mmu_notifier_release(struct mm_struct *mm);
203extern int __mmu_notifier_clear_flush_young(struct mm_struct *mm,
Andres Lagar-Cavilla57128462014-09-22 14:54:42 -0700204 unsigned long start,
205 unsigned long end);
Andrea Arcangeli8ee53822011-01-13 15:47:10 -0800206extern int __mmu_notifier_test_young(struct mm_struct *mm,
207 unsigned long address);
Izik Eidus828502d2009-09-21 17:01:51 -0700208extern void __mmu_notifier_change_pte(struct mm_struct *mm,
209 unsigned long address, pte_t pte);
Andrea Arcangelicddb8a52008-07-28 15:46:29 -0700210extern void __mmu_notifier_invalidate_page(struct mm_struct *mm,
211 unsigned long address);
212extern void __mmu_notifier_invalidate_range_start(struct mm_struct *mm,
213 unsigned long start, unsigned long end);
214extern void __mmu_notifier_invalidate_range_end(struct mm_struct *mm,
215 unsigned long start, unsigned long end);
Joerg Roedel0f0a3272014-11-13 13:46:09 +1100216extern void __mmu_notifier_invalidate_range(struct mm_struct *mm,
217 unsigned long start, unsigned long end);
Andrea Arcangelicddb8a52008-07-28 15:46:29 -0700218
219static inline void mmu_notifier_release(struct mm_struct *mm)
220{
221 if (mm_has_notifiers(mm))
222 __mmu_notifier_release(mm);
223}
224
225static inline int mmu_notifier_clear_flush_young(struct mm_struct *mm,
Andres Lagar-Cavilla57128462014-09-22 14:54:42 -0700226 unsigned long start,
227 unsigned long end)
Andrea Arcangelicddb8a52008-07-28 15:46:29 -0700228{
229 if (mm_has_notifiers(mm))
Andres Lagar-Cavilla57128462014-09-22 14:54:42 -0700230 return __mmu_notifier_clear_flush_young(mm, start, end);
Andrea Arcangelicddb8a52008-07-28 15:46:29 -0700231 return 0;
232}
233
Andrea Arcangeli8ee53822011-01-13 15:47:10 -0800234static inline int mmu_notifier_test_young(struct mm_struct *mm,
235 unsigned long address)
236{
237 if (mm_has_notifiers(mm))
238 return __mmu_notifier_test_young(mm, address);
239 return 0;
240}
241
Izik Eidus828502d2009-09-21 17:01:51 -0700242static inline void mmu_notifier_change_pte(struct mm_struct *mm,
243 unsigned long address, pte_t pte)
244{
245 if (mm_has_notifiers(mm))
246 __mmu_notifier_change_pte(mm, address, pte);
247}
248
Andrea Arcangelicddb8a52008-07-28 15:46:29 -0700249static inline void mmu_notifier_invalidate_page(struct mm_struct *mm,
250 unsigned long address)
251{
252 if (mm_has_notifiers(mm))
253 __mmu_notifier_invalidate_page(mm, address);
254}
255
256static inline void mmu_notifier_invalidate_range_start(struct mm_struct *mm,
257 unsigned long start, unsigned long end)
258{
259 if (mm_has_notifiers(mm))
260 __mmu_notifier_invalidate_range_start(mm, start, end);
261}
262
263static inline void mmu_notifier_invalidate_range_end(struct mm_struct *mm,
264 unsigned long start, unsigned long end)
265{
266 if (mm_has_notifiers(mm))
267 __mmu_notifier_invalidate_range_end(mm, start, end);
268}
269
Joerg Roedel1897bdc2014-11-13 13:46:09 +1100270static inline void mmu_notifier_invalidate_range(struct mm_struct *mm,
271 unsigned long start, unsigned long end)
272{
Joerg Roedel0f0a3272014-11-13 13:46:09 +1100273 if (mm_has_notifiers(mm))
274 __mmu_notifier_invalidate_range(mm, start, end);
Joerg Roedel1897bdc2014-11-13 13:46:09 +1100275}
276
Andrea Arcangelicddb8a52008-07-28 15:46:29 -0700277static inline void mmu_notifier_mm_init(struct mm_struct *mm)
278{
279 mm->mmu_notifier_mm = NULL;
280}
281
282static inline void mmu_notifier_mm_destroy(struct mm_struct *mm)
283{
284 if (mm_has_notifiers(mm))
285 __mmu_notifier_mm_destroy(mm);
286}
287
Andrea Arcangelicddb8a52008-07-28 15:46:29 -0700288#define ptep_clear_flush_young_notify(__vma, __address, __ptep) \
289({ \
290 int __young; \
291 struct vm_area_struct *___vma = __vma; \
292 unsigned long ___address = __address; \
293 __young = ptep_clear_flush_young(___vma, ___address, __ptep); \
294 __young |= mmu_notifier_clear_flush_young(___vma->vm_mm, \
Andres Lagar-Cavilla57128462014-09-22 14:54:42 -0700295 ___address, \
296 ___address + \
297 PAGE_SIZE); \
Andrea Arcangelicddb8a52008-07-28 15:46:29 -0700298 __young; \
299})
300
Andrea Arcangeli91a4ee22011-01-13 15:46:44 -0800301#define pmdp_clear_flush_young_notify(__vma, __address, __pmdp) \
302({ \
303 int __young; \
304 struct vm_area_struct *___vma = __vma; \
305 unsigned long ___address = __address; \
306 __young = pmdp_clear_flush_young(___vma, ___address, __pmdp); \
307 __young |= mmu_notifier_clear_flush_young(___vma->vm_mm, \
Andres Lagar-Cavilla57128462014-09-22 14:54:42 -0700308 ___address, \
309 ___address + \
310 PMD_SIZE); \
Andrea Arcangeli91a4ee22011-01-13 15:46:44 -0800311 __young; \
312})
313
Joerg Roedel34ee6452014-11-13 13:46:09 +1100314#define ptep_clear_flush_notify(__vma, __address, __ptep) \
315({ \
316 unsigned long ___addr = __address & PAGE_MASK; \
317 struct mm_struct *___mm = (__vma)->vm_mm; \
318 pte_t ___pte; \
319 \
320 ___pte = ptep_clear_flush(__vma, __address, __ptep); \
321 mmu_notifier_invalidate_range(___mm, ___addr, \
322 ___addr + PAGE_SIZE); \
323 \
324 ___pte; \
325})
326
327#define pmdp_clear_flush_notify(__vma, __haddr, __pmd) \
328({ \
329 unsigned long ___haddr = __haddr & HPAGE_PMD_MASK; \
330 struct mm_struct *___mm = (__vma)->vm_mm; \
331 pmd_t ___pmd; \
332 \
333 ___pmd = pmdp_clear_flush(__vma, __haddr, __pmd); \
334 mmu_notifier_invalidate_range(___mm, ___haddr, \
335 ___haddr + HPAGE_PMD_SIZE); \
336 \
337 ___pmd; \
338})
339
340#define pmdp_get_and_clear_notify(__mm, __haddr, __pmd) \
341({ \
342 unsigned long ___haddr = __haddr & HPAGE_PMD_MASK; \
343 pmd_t ___pmd; \
344 \
345 ___pmd = pmdp_get_and_clear(__mm, __haddr, __pmd); \
346 mmu_notifier_invalidate_range(__mm, ___haddr, \
347 ___haddr + HPAGE_PMD_SIZE); \
348 \
349 ___pmd; \
350})
351
Xiao Guangrong48af0d72012-10-08 16:29:23 -0700352/*
353 * set_pte_at_notify() sets the pte _after_ running the notifier.
354 * This is safe to start by updating the secondary MMUs, because the primary MMU
355 * pte invalidate must have already happened with a ptep_clear_flush() before
356 * set_pte_at_notify() has been invoked. Updating the secondary MMUs first is
357 * required when we change both the protection of the mapping from read-only to
358 * read-write and the pfn (like during copy on write page faults). Otherwise the
359 * old page would remain mapped readonly in the secondary MMUs after the new
360 * page is already writable by some CPU through the primary MMU.
361 */
Izik Eidus828502d2009-09-21 17:01:51 -0700362#define set_pte_at_notify(__mm, __address, __ptep, __pte) \
363({ \
364 struct mm_struct *___mm = __mm; \
365 unsigned long ___address = __address; \
366 pte_t ___pte = __pte; \
367 \
Izik Eidus828502d2009-09-21 17:01:51 -0700368 mmu_notifier_change_pte(___mm, ___address, ___pte); \
Xiao Guangrong48af0d72012-10-08 16:29:23 -0700369 set_pte_at(___mm, ___address, __ptep, ___pte); \
Izik Eidus828502d2009-09-21 17:01:51 -0700370})
371
Peter Zijlstrab9722162014-08-06 16:08:20 -0700372extern void mmu_notifier_call_srcu(struct rcu_head *rcu,
373 void (*func)(struct rcu_head *rcu));
374extern void mmu_notifier_synchronize(void);
375
Andrea Arcangelicddb8a52008-07-28 15:46:29 -0700376#else /* CONFIG_MMU_NOTIFIER */
377
378static inline void mmu_notifier_release(struct mm_struct *mm)
379{
380}
381
382static inline int mmu_notifier_clear_flush_young(struct mm_struct *mm,
Andres Lagar-Cavilla57128462014-09-22 14:54:42 -0700383 unsigned long start,
384 unsigned long end)
Andrea Arcangelicddb8a52008-07-28 15:46:29 -0700385{
386 return 0;
387}
388
Andrea Arcangeli8ee53822011-01-13 15:47:10 -0800389static inline int mmu_notifier_test_young(struct mm_struct *mm,
390 unsigned long address)
391{
392 return 0;
393}
394
Izik Eidus828502d2009-09-21 17:01:51 -0700395static inline void mmu_notifier_change_pte(struct mm_struct *mm,
396 unsigned long address, pte_t pte)
397{
398}
399
Andrea Arcangelicddb8a52008-07-28 15:46:29 -0700400static inline void mmu_notifier_invalidate_page(struct mm_struct *mm,
401 unsigned long address)
402{
403}
404
405static inline void mmu_notifier_invalidate_range_start(struct mm_struct *mm,
406 unsigned long start, unsigned long end)
407{
408}
409
410static inline void mmu_notifier_invalidate_range_end(struct mm_struct *mm,
411 unsigned long start, unsigned long end)
412{
413}
414
Joerg Roedel1897bdc2014-11-13 13:46:09 +1100415static inline void mmu_notifier_invalidate_range(struct mm_struct *mm,
416 unsigned long start, unsigned long end)
417{
418}
419
Andrea Arcangelicddb8a52008-07-28 15:46:29 -0700420static inline void mmu_notifier_mm_init(struct mm_struct *mm)
421{
422}
423
424static inline void mmu_notifier_mm_destroy(struct mm_struct *mm)
425{
426}
427
428#define ptep_clear_flush_young_notify ptep_clear_flush_young
Andrea Arcangeli91a4ee22011-01-13 15:46:44 -0800429#define pmdp_clear_flush_young_notify pmdp_clear_flush_young
Joerg Roedel34ee6452014-11-13 13:46:09 +1100430#define ptep_clear_flush_notify ptep_clear_flush
431#define pmdp_clear_flush_notify pmdp_clear_flush
432#define pmdp_get_and_clear_notify pmdp_get_and_clear
Izik Eidus828502d2009-09-21 17:01:51 -0700433#define set_pte_at_notify set_pte_at
Andrea Arcangelicddb8a52008-07-28 15:46:29 -0700434
435#endif /* CONFIG_MMU_NOTIFIER */
436
437#endif /* _LINUX_MMU_NOTIFIER_H */