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cddb8a5c AA |
1 | #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> | |
21a92735 | 7 | #include <linux/srcu.h> |
cddb8a5c AA |
8 | |
9 | struct mmu_notifier; | |
10 | struct 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 | */ | |
20 | struct 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 | ||
27 | struct 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. | |
57128468 ALC |
60 | * Start-end is necessary in case the secondary MMU is mapping the page |
61 | * at a smaller granularity than the primary MMU. | |
cddb8a5c AA |
62 | */ |
63 | int (*clear_flush_young)(struct mmu_notifier *mn, | |
64 | struct mm_struct *mm, | |
57128468 ALC |
65 | unsigned long start, |
66 | unsigned long end); | |
cddb8a5c | 67 | |
1d7715c6 VD |
68 | /* |
69 | * clear_young is a lightweight version of clear_flush_young. Like the | |
70 | * latter, it is supposed to test-and-clear the young/accessed bitflag | |
71 | * in the secondary pte, but it may omit flushing the secondary tlb. | |
72 | */ | |
73 | int (*clear_young)(struct mmu_notifier *mn, | |
74 | struct mm_struct *mm, | |
75 | unsigned long start, | |
76 | unsigned long end); | |
77 | ||
8ee53820 AA |
78 | /* |
79 | * test_young is called to check the young/accessed bitflag in | |
80 | * the secondary pte. This is used to know if the page is | |
81 | * frequently used without actually clearing the flag or tearing | |
82 | * down the secondary mapping on the page. | |
83 | */ | |
84 | int (*test_young)(struct mmu_notifier *mn, | |
85 | struct mm_struct *mm, | |
86 | unsigned long address); | |
87 | ||
828502d3 IE |
88 | /* |
89 | * change_pte is called in cases that pte mapping to page is changed: | |
90 | * for example, when ksm remaps pte to point to a new shared page. | |
91 | */ | |
92 | void (*change_pte)(struct mmu_notifier *mn, | |
93 | struct mm_struct *mm, | |
94 | unsigned long address, | |
95 | pte_t pte); | |
96 | ||
cddb8a5c AA |
97 | /* |
98 | * invalidate_range_start() and invalidate_range_end() must be | |
99 | * paired and are called only when the mmap_sem and/or the | |
0f0a327f JR |
100 | * locks protecting the reverse maps are held. If the subsystem |
101 | * can't guarantee that no additional references are taken to | |
102 | * the pages in the range, it has to implement the | |
103 | * invalidate_range() notifier to remove any references taken | |
104 | * after invalidate_range_start(). | |
cddb8a5c AA |
105 | * |
106 | * Invalidation of multiple concurrent ranges may be | |
107 | * optionally permitted by the driver. Either way the | |
108 | * establishment of sptes is forbidden in the range passed to | |
109 | * invalidate_range_begin/end for the whole duration of the | |
110 | * invalidate_range_begin/end critical section. | |
111 | * | |
112 | * invalidate_range_start() is called when all pages in the | |
113 | * range are still mapped and have at least a refcount of one. | |
114 | * | |
115 | * invalidate_range_end() is called when all pages in the | |
116 | * range have been unmapped and the pages have been freed by | |
117 | * the VM. | |
118 | * | |
119 | * The VM will remove the page table entries and potentially | |
120 | * the page between invalidate_range_start() and | |
121 | * invalidate_range_end(). If the page must not be freed | |
122 | * because of pending I/O or other circumstances then the | |
123 | * invalidate_range_start() callback (or the initial mapping | |
124 | * by the driver) must make sure that the refcount is kept | |
125 | * elevated. | |
126 | * | |
127 | * If the driver increases the refcount when the pages are | |
128 | * initially mapped into an address space then either | |
129 | * invalidate_range_start() or invalidate_range_end() may | |
130 | * decrease the refcount. If the refcount is decreased on | |
131 | * invalidate_range_start() then the VM can free pages as page | |
132 | * table entries are removed. If the refcount is only | |
133 | * droppped on invalidate_range_end() then the driver itself | |
134 | * will drop the last refcount but it must take care to flush | |
135 | * any secondary tlb before doing the final free on the | |
136 | * page. Pages will no longer be referenced by the linux | |
137 | * address space but may still be referenced by sptes until | |
138 | * the last refcount is dropped. | |
139 | */ | |
140 | void (*invalidate_range_start)(struct mmu_notifier *mn, | |
141 | struct mm_struct *mm, | |
142 | unsigned long start, unsigned long end); | |
143 | void (*invalidate_range_end)(struct mmu_notifier *mn, | |
144 | struct mm_struct *mm, | |
145 | unsigned long start, unsigned long end); | |
0f0a327f JR |
146 | |
147 | /* | |
148 | * invalidate_range() is either called between | |
149 | * invalidate_range_start() and invalidate_range_end() when the | |
150 | * VM has to free pages that where unmapped, but before the | |
151 | * pages are actually freed, or outside of _start()/_end() when | |
152 | * a (remote) TLB is necessary. | |
153 | * | |
154 | * If invalidate_range() is used to manage a non-CPU TLB with | |
155 | * shared page-tables, it not necessary to implement the | |
156 | * invalidate_range_start()/end() notifiers, as | |
157 | * invalidate_range() alread catches the points in time when an | |
158 | * external TLB range needs to be flushed. | |
159 | * | |
160 | * The invalidate_range() function is called under the ptl | |
161 | * spin-lock and not allowed to sleep. | |
162 | * | |
163 | * Note that this function might be called with just a sub-range | |
164 | * of what was passed to invalidate_range_start()/end(), if | |
165 | * called between those functions. | |
166 | */ | |
167 | void (*invalidate_range)(struct mmu_notifier *mn, struct mm_struct *mm, | |
168 | unsigned long start, unsigned long end); | |
cddb8a5c AA |
169 | }; |
170 | ||
171 | /* | |
172 | * The notifier chains are protected by mmap_sem and/or the reverse map | |
173 | * semaphores. Notifier chains are only changed when all reverse maps and | |
174 | * the mmap_sem locks are taken. | |
175 | * | |
176 | * Therefore notifier chains can only be traversed when either | |
177 | * | |
178 | * 1. mmap_sem is held. | |
c8c06efa | 179 | * 2. One of the reverse map locks is held (i_mmap_rwsem or anon_vma->rwsem). |
cddb8a5c AA |
180 | * 3. No other concurrent thread can access the list (release) |
181 | */ | |
182 | struct mmu_notifier { | |
183 | struct hlist_node hlist; | |
184 | const struct mmu_notifier_ops *ops; | |
185 | }; | |
186 | ||
187 | static inline int mm_has_notifiers(struct mm_struct *mm) | |
188 | { | |
189 | return unlikely(mm->mmu_notifier_mm); | |
190 | } | |
191 | ||
192 | extern int mmu_notifier_register(struct mmu_notifier *mn, | |
193 | struct mm_struct *mm); | |
194 | extern int __mmu_notifier_register(struct mmu_notifier *mn, | |
195 | struct mm_struct *mm); | |
196 | extern void mmu_notifier_unregister(struct mmu_notifier *mn, | |
197 | struct mm_struct *mm); | |
b972216e PZ |
198 | extern void mmu_notifier_unregister_no_release(struct mmu_notifier *mn, |
199 | struct mm_struct *mm); | |
cddb8a5c AA |
200 | extern void __mmu_notifier_mm_destroy(struct mm_struct *mm); |
201 | extern void __mmu_notifier_release(struct mm_struct *mm); | |
202 | extern int __mmu_notifier_clear_flush_young(struct mm_struct *mm, | |
57128468 ALC |
203 | unsigned long start, |
204 | unsigned long end); | |
1d7715c6 VD |
205 | extern int __mmu_notifier_clear_young(struct mm_struct *mm, |
206 | unsigned long start, | |
207 | unsigned long end); | |
8ee53820 AA |
208 | extern int __mmu_notifier_test_young(struct mm_struct *mm, |
209 | unsigned long address); | |
828502d3 IE |
210 | extern void __mmu_notifier_change_pte(struct mm_struct *mm, |
211 | unsigned long address, pte_t pte); | |
cddb8a5c AA |
212 | extern void __mmu_notifier_invalidate_range_start(struct mm_struct *mm, |
213 | unsigned long start, unsigned long end); | |
214 | extern void __mmu_notifier_invalidate_range_end(struct mm_struct *mm, | |
215 | unsigned long start, unsigned long end); | |
0f0a327f JR |
216 | extern void __mmu_notifier_invalidate_range(struct mm_struct *mm, |
217 | unsigned long start, unsigned long end); | |
cddb8a5c AA |
218 | |
219 | static inline void mmu_notifier_release(struct mm_struct *mm) | |
220 | { | |
221 | if (mm_has_notifiers(mm)) | |
222 | __mmu_notifier_release(mm); | |
223 | } | |
224 | ||
225 | static inline int mmu_notifier_clear_flush_young(struct mm_struct *mm, | |
57128468 ALC |
226 | unsigned long start, |
227 | unsigned long end) | |
cddb8a5c AA |
228 | { |
229 | if (mm_has_notifiers(mm)) | |
57128468 | 230 | return __mmu_notifier_clear_flush_young(mm, start, end); |
cddb8a5c AA |
231 | return 0; |
232 | } | |
233 | ||
1d7715c6 VD |
234 | static inline int mmu_notifier_clear_young(struct mm_struct *mm, |
235 | unsigned long start, | |
236 | unsigned long end) | |
237 | { | |
238 | if (mm_has_notifiers(mm)) | |
239 | return __mmu_notifier_clear_young(mm, start, end); | |
240 | return 0; | |
241 | } | |
242 | ||
8ee53820 AA |
243 | static inline int mmu_notifier_test_young(struct mm_struct *mm, |
244 | unsigned long address) | |
245 | { | |
246 | if (mm_has_notifiers(mm)) | |
247 | return __mmu_notifier_test_young(mm, address); | |
248 | return 0; | |
249 | } | |
250 | ||
828502d3 IE |
251 | static inline void mmu_notifier_change_pte(struct mm_struct *mm, |
252 | unsigned long address, pte_t pte) | |
253 | { | |
254 | if (mm_has_notifiers(mm)) | |
255 | __mmu_notifier_change_pte(mm, address, pte); | |
256 | } | |
257 | ||
cddb8a5c AA |
258 | static inline void mmu_notifier_invalidate_range_start(struct mm_struct *mm, |
259 | unsigned long start, unsigned long end) | |
260 | { | |
261 | if (mm_has_notifiers(mm)) | |
262 | __mmu_notifier_invalidate_range_start(mm, start, end); | |
263 | } | |
264 | ||
265 | static inline void mmu_notifier_invalidate_range_end(struct mm_struct *mm, | |
266 | unsigned long start, unsigned long end) | |
267 | { | |
268 | if (mm_has_notifiers(mm)) | |
269 | __mmu_notifier_invalidate_range_end(mm, start, end); | |
270 | } | |
271 | ||
1897bdc4 JR |
272 | static inline void mmu_notifier_invalidate_range(struct mm_struct *mm, |
273 | unsigned long start, unsigned long end) | |
274 | { | |
0f0a327f JR |
275 | if (mm_has_notifiers(mm)) |
276 | __mmu_notifier_invalidate_range(mm, start, end); | |
1897bdc4 JR |
277 | } |
278 | ||
cddb8a5c AA |
279 | static inline void mmu_notifier_mm_init(struct mm_struct *mm) |
280 | { | |
281 | mm->mmu_notifier_mm = NULL; | |
282 | } | |
283 | ||
284 | static inline void mmu_notifier_mm_destroy(struct mm_struct *mm) | |
285 | { | |
286 | if (mm_has_notifiers(mm)) | |
287 | __mmu_notifier_mm_destroy(mm); | |
288 | } | |
289 | ||
cddb8a5c AA |
290 | #define ptep_clear_flush_young_notify(__vma, __address, __ptep) \ |
291 | ({ \ | |
292 | int __young; \ | |
293 | struct vm_area_struct *___vma = __vma; \ | |
294 | unsigned long ___address = __address; \ | |
295 | __young = ptep_clear_flush_young(___vma, ___address, __ptep); \ | |
296 | __young |= mmu_notifier_clear_flush_young(___vma->vm_mm, \ | |
57128468 ALC |
297 | ___address, \ |
298 | ___address + \ | |
299 | PAGE_SIZE); \ | |
cddb8a5c AA |
300 | __young; \ |
301 | }) | |
302 | ||
91a4ee26 AA |
303 | #define pmdp_clear_flush_young_notify(__vma, __address, __pmdp) \ |
304 | ({ \ | |
305 | int __young; \ | |
306 | struct vm_area_struct *___vma = __vma; \ | |
307 | unsigned long ___address = __address; \ | |
308 | __young = pmdp_clear_flush_young(___vma, ___address, __pmdp); \ | |
309 | __young |= mmu_notifier_clear_flush_young(___vma->vm_mm, \ | |
57128468 ALC |
310 | ___address, \ |
311 | ___address + \ | |
312 | PMD_SIZE); \ | |
91a4ee26 AA |
313 | __young; \ |
314 | }) | |
315 | ||
1d7715c6 VD |
316 | #define ptep_clear_young_notify(__vma, __address, __ptep) \ |
317 | ({ \ | |
318 | int __young; \ | |
319 | struct vm_area_struct *___vma = __vma; \ | |
320 | unsigned long ___address = __address; \ | |
321 | __young = ptep_test_and_clear_young(___vma, ___address, __ptep);\ | |
322 | __young |= mmu_notifier_clear_young(___vma->vm_mm, ___address, \ | |
323 | ___address + PAGE_SIZE); \ | |
324 | __young; \ | |
325 | }) | |
326 | ||
327 | #define pmdp_clear_young_notify(__vma, __address, __pmdp) \ | |
328 | ({ \ | |
329 | int __young; \ | |
330 | struct vm_area_struct *___vma = __vma; \ | |
331 | unsigned long ___address = __address; \ | |
332 | __young = pmdp_test_and_clear_young(___vma, ___address, __pmdp);\ | |
333 | __young |= mmu_notifier_clear_young(___vma->vm_mm, ___address, \ | |
334 | ___address + PMD_SIZE); \ | |
335 | __young; \ | |
336 | }) | |
337 | ||
34ee645e JR |
338 | #define ptep_clear_flush_notify(__vma, __address, __ptep) \ |
339 | ({ \ | |
340 | unsigned long ___addr = __address & PAGE_MASK; \ | |
341 | struct mm_struct *___mm = (__vma)->vm_mm; \ | |
342 | pte_t ___pte; \ | |
343 | \ | |
344 | ___pte = ptep_clear_flush(__vma, __address, __ptep); \ | |
345 | mmu_notifier_invalidate_range(___mm, ___addr, \ | |
346 | ___addr + PAGE_SIZE); \ | |
347 | \ | |
348 | ___pte; \ | |
349 | }) | |
350 | ||
8809aa2d | 351 | #define pmdp_huge_clear_flush_notify(__vma, __haddr, __pmd) \ |
34ee645e JR |
352 | ({ \ |
353 | unsigned long ___haddr = __haddr & HPAGE_PMD_MASK; \ | |
354 | struct mm_struct *___mm = (__vma)->vm_mm; \ | |
355 | pmd_t ___pmd; \ | |
356 | \ | |
8809aa2d | 357 | ___pmd = pmdp_huge_clear_flush(__vma, __haddr, __pmd); \ |
34ee645e JR |
358 | mmu_notifier_invalidate_range(___mm, ___haddr, \ |
359 | ___haddr + HPAGE_PMD_SIZE); \ | |
360 | \ | |
361 | ___pmd; \ | |
362 | }) | |
363 | ||
a00cc7d9 MW |
364 | #define pudp_huge_clear_flush_notify(__vma, __haddr, __pud) \ |
365 | ({ \ | |
366 | unsigned long ___haddr = __haddr & HPAGE_PUD_MASK; \ | |
367 | struct mm_struct *___mm = (__vma)->vm_mm; \ | |
368 | pud_t ___pud; \ | |
369 | \ | |
370 | ___pud = pudp_huge_clear_flush(__vma, __haddr, __pud); \ | |
371 | mmu_notifier_invalidate_range(___mm, ___haddr, \ | |
372 | ___haddr + HPAGE_PUD_SIZE); \ | |
373 | \ | |
374 | ___pud; \ | |
375 | }) | |
376 | ||
48af0d7c XG |
377 | /* |
378 | * set_pte_at_notify() sets the pte _after_ running the notifier. | |
379 | * This is safe to start by updating the secondary MMUs, because the primary MMU | |
380 | * pte invalidate must have already happened with a ptep_clear_flush() before | |
381 | * set_pte_at_notify() has been invoked. Updating the secondary MMUs first is | |
382 | * required when we change both the protection of the mapping from read-only to | |
383 | * read-write and the pfn (like during copy on write page faults). Otherwise the | |
384 | * old page would remain mapped readonly in the secondary MMUs after the new | |
385 | * page is already writable by some CPU through the primary MMU. | |
386 | */ | |
828502d3 IE |
387 | #define set_pte_at_notify(__mm, __address, __ptep, __pte) \ |
388 | ({ \ | |
389 | struct mm_struct *___mm = __mm; \ | |
390 | unsigned long ___address = __address; \ | |
391 | pte_t ___pte = __pte; \ | |
392 | \ | |
828502d3 | 393 | mmu_notifier_change_pte(___mm, ___address, ___pte); \ |
48af0d7c | 394 | set_pte_at(___mm, ___address, __ptep, ___pte); \ |
828502d3 IE |
395 | }) |
396 | ||
b972216e PZ |
397 | extern void mmu_notifier_call_srcu(struct rcu_head *rcu, |
398 | void (*func)(struct rcu_head *rcu)); | |
399 | extern void mmu_notifier_synchronize(void); | |
400 | ||
cddb8a5c AA |
401 | #else /* CONFIG_MMU_NOTIFIER */ |
402 | ||
5cc96a7b MH |
403 | static inline int mm_has_notifiers(struct mm_struct *mm) |
404 | { | |
405 | return 0; | |
406 | } | |
407 | ||
cddb8a5c AA |
408 | static inline void mmu_notifier_release(struct mm_struct *mm) |
409 | { | |
410 | } | |
411 | ||
412 | static inline int mmu_notifier_clear_flush_young(struct mm_struct *mm, | |
57128468 ALC |
413 | unsigned long start, |
414 | unsigned long end) | |
8ee53820 AA |
415 | { |
416 | return 0; | |
417 | } | |
418 | ||
419 | static inline int mmu_notifier_test_young(struct mm_struct *mm, | |
420 | unsigned long address) | |
cddb8a5c AA |
421 | { |
422 | return 0; | |
423 | } | |
424 | ||
828502d3 IE |
425 | static inline void mmu_notifier_change_pte(struct mm_struct *mm, |
426 | unsigned long address, pte_t pte) | |
427 | { | |
428 | } | |
429 | ||
cddb8a5c AA |
430 | static inline void mmu_notifier_invalidate_range_start(struct mm_struct *mm, |
431 | unsigned long start, unsigned long end) | |
432 | { | |
433 | } | |
434 | ||
435 | static inline void mmu_notifier_invalidate_range_end(struct mm_struct *mm, | |
436 | unsigned long start, unsigned long end) | |
437 | { | |
438 | } | |
439 | ||
1897bdc4 JR |
440 | static inline void mmu_notifier_invalidate_range(struct mm_struct *mm, |
441 | unsigned long start, unsigned long end) | |
442 | { | |
443 | } | |
444 | ||
cddb8a5c AA |
445 | static inline void mmu_notifier_mm_init(struct mm_struct *mm) |
446 | { | |
447 | } | |
448 | ||
449 | static inline void mmu_notifier_mm_destroy(struct mm_struct *mm) | |
450 | { | |
451 | } | |
452 | ||
453 | #define ptep_clear_flush_young_notify ptep_clear_flush_young | |
91a4ee26 | 454 | #define pmdp_clear_flush_young_notify pmdp_clear_flush_young |
33c3fc71 VD |
455 | #define ptep_clear_young_notify ptep_test_and_clear_young |
456 | #define pmdp_clear_young_notify pmdp_test_and_clear_young | |
34ee645e | 457 | #define ptep_clear_flush_notify ptep_clear_flush |
8809aa2d | 458 | #define pmdp_huge_clear_flush_notify pmdp_huge_clear_flush |
a00cc7d9 | 459 | #define pudp_huge_clear_flush_notify pudp_huge_clear_flush |
828502d3 | 460 | #define set_pte_at_notify set_pte_at |
cddb8a5c AA |
461 | |
462 | #endif /* CONFIG_MMU_NOTIFIER */ | |
463 | ||
464 | #endif /* _LINUX_MMU_NOTIFIER_H */ |