1 /* SPDX-License-Identifier: GPL-2.0 */
2 #ifndef _LINUX_MMU_NOTIFIER_H
3 #define _LINUX_MMU_NOTIFIER_H
4 
5 #include <linux/list.h>
6 #include <linux/spinlock.h>
7 #include <linux/mm_types.h>
8 #include <linux/mmap_lock.h>
9 #include <linux/srcu.h>
10 #include <linux/interval_tree.h>
11 
12 struct mmu_notifier_subscriptions;
13 struct mmu_notifier;
14 struct mmu_notifier_range;
15 struct mmu_interval_notifier;
16 
17 /**
18  * enum mmu_notifier_event - reason for the mmu notifier callback
19  * @MMU_NOTIFY_UNMAP: either munmap() that unmap the range or a mremap() that
20  * move the range
21  *
22  * @MMU_NOTIFY_CLEAR: clear page table entry (many reasons for this like
23  * madvise() or replacing a page by another one, ...).
24  *
25  * @MMU_NOTIFY_PROTECTION_VMA: update is due to protection change for the range
26  * ie using the vma access permission (vm_page_prot) to update the whole range
27  * is enough no need to inspect changes to the CPU page table (mprotect()
28  * syscall)
29  *
30  * @MMU_NOTIFY_PROTECTION_PAGE: update is due to change in read/write flag for
31  * pages in the range so to mirror those changes the user must inspect the CPU
32  * page table (from the end callback).
33  *
34  * @MMU_NOTIFY_SOFT_DIRTY: soft dirty accounting (still same page and same
35  * access flags). User should soft dirty the page in the end callback to make
36  * sure that anyone relying on soft dirtiness catch pages that might be written
37  * through non CPU mappings.
38  *
39  * @MMU_NOTIFY_RELEASE: used during mmu_interval_notifier invalidate to signal
40  * that the mm refcount is zero and the range is no longer accessible.
41  *
42  * @MMU_NOTIFY_MIGRATE: used during migrate_vma_collect() invalidate to signal
43  * a device driver to possibly ignore the invalidation if the
44  * owner field matches the driver's device private pgmap owner.
45  *
46  * @MMU_NOTIFY_EXCLUSIVE: to signal a device driver that the device will no
47  * longer have exclusive access to the page. When sent during creation of an
48  * exclusive range the owner will be initialised to the value provided by the
49  * caller of make_device_exclusive_range(), otherwise the owner will be NULL.
50  */
51 enum mmu_notifier_event {
52 	MMU_NOTIFY_UNMAP = 0,
53 	MMU_NOTIFY_CLEAR,
54 	MMU_NOTIFY_PROTECTION_VMA,
55 	MMU_NOTIFY_PROTECTION_PAGE,
56 	MMU_NOTIFY_SOFT_DIRTY,
57 	MMU_NOTIFY_RELEASE,
58 	MMU_NOTIFY_MIGRATE,
59 	MMU_NOTIFY_EXCLUSIVE,
60 };
61 
62 #define MMU_NOTIFIER_RANGE_BLOCKABLE (1 << 0)
63 
64 struct mmu_notifier_ops {
65 	/*
66 	 * Called either by mmu_notifier_unregister or when the mm is
67 	 * being destroyed by exit_mmap, always before all pages are
68 	 * freed. This can run concurrently with other mmu notifier
69 	 * methods (the ones invoked outside the mm context) and it
70 	 * should tear down all secondary mmu mappings and freeze the
71 	 * secondary mmu. If this method isn't implemented you've to
72 	 * be sure that nothing could possibly write to the pages
73 	 * through the secondary mmu by the time the last thread with
74 	 * tsk->mm == mm exits.
75 	 *
76 	 * As side note: the pages freed after ->release returns could
77 	 * be immediately reallocated by the gart at an alias physical
78 	 * address with a different cache model, so if ->release isn't
79 	 * implemented because all _software_ driven memory accesses
80 	 * through the secondary mmu are terminated by the time the
81 	 * last thread of this mm quits, you've also to be sure that
82 	 * speculative _hardware_ operations can't allocate dirty
83 	 * cachelines in the cpu that could not be snooped and made
84 	 * coherent with the other read and write operations happening
85 	 * through the gart alias address, so leading to memory
86 	 * corruption.
87 	 */
88 	void (*release)(struct mmu_notifier *subscription,
89 			struct mm_struct *mm);
90 
91 	/*
92 	 * clear_flush_young is called after the VM is
93 	 * test-and-clearing the young/accessed bitflag in the
94 	 * pte. This way the VM will provide proper aging to the
95 	 * accesses to the page through the secondary MMUs and not
96 	 * only to the ones through the Linux pte.
97 	 * Start-end is necessary in case the secondary MMU is mapping the page
98 	 * at a smaller granularity than the primary MMU.
99 	 */
100 	int (*clear_flush_young)(struct mmu_notifier *subscription,
101 				 struct mm_struct *mm,
102 				 unsigned long start,
103 				 unsigned long end);
104 
105 	/*
106 	 * clear_young is a lightweight version of clear_flush_young. Like the
107 	 * latter, it is supposed to test-and-clear the young/accessed bitflag
108 	 * in the secondary pte, but it may omit flushing the secondary tlb.
109 	 */
110 	int (*clear_young)(struct mmu_notifier *subscription,
111 			   struct mm_struct *mm,
112 			   unsigned long start,
113 			   unsigned long end);
114 
115 	/*
116 	 * test_young is called to check the young/accessed bitflag in
117 	 * the secondary pte. This is used to know if the page is
118 	 * frequently used without actually clearing the flag or tearing
119 	 * down the secondary mapping on the page.
120 	 */
121 	int (*test_young)(struct mmu_notifier *subscription,
122 			  struct mm_struct *mm,
123 			  unsigned long address);
124 
125 	/*
126 	 * change_pte is called in cases that pte mapping to page is changed:
127 	 * for example, when ksm remaps pte to point to a new shared page.
128 	 */
129 	void (*change_pte)(struct mmu_notifier *subscription,
130 			   struct mm_struct *mm,
131 			   unsigned long address,
132 			   pte_t pte);
133 
134 	/*
135 	 * invalidate_range_start() and invalidate_range_end() must be
136 	 * paired and are called only when the mmap_lock and/or the
137 	 * locks protecting the reverse maps are held. If the subsystem
138 	 * can't guarantee that no additional references are taken to
139 	 * the pages in the range, it has to implement the
140 	 * invalidate_range() notifier to remove any references taken
141 	 * after invalidate_range_start().
142 	 *
143 	 * Invalidation of multiple concurrent ranges may be
144 	 * optionally permitted by the driver. Either way the
145 	 * establishment of sptes is forbidden in the range passed to
146 	 * invalidate_range_begin/end for the whole duration of the
147 	 * invalidate_range_begin/end critical section.
148 	 *
149 	 * invalidate_range_start() is called when all pages in the
150 	 * range are still mapped and have at least a refcount of one.
151 	 *
152 	 * invalidate_range_end() is called when all pages in the
153 	 * range have been unmapped and the pages have been freed by
154 	 * the VM.
155 	 *
156 	 * The VM will remove the page table entries and potentially
157 	 * the page between invalidate_range_start() and
158 	 * invalidate_range_end(). If the page must not be freed
159 	 * because of pending I/O or other circumstances then the
160 	 * invalidate_range_start() callback (or the initial mapping
161 	 * by the driver) must make sure that the refcount is kept
162 	 * elevated.
163 	 *
164 	 * If the driver increases the refcount when the pages are
165 	 * initially mapped into an address space then either
166 	 * invalidate_range_start() or invalidate_range_end() may
167 	 * decrease the refcount. If the refcount is decreased on
168 	 * invalidate_range_start() then the VM can free pages as page
169 	 * table entries are removed.  If the refcount is only
170 	 * dropped on invalidate_range_end() then the driver itself
171 	 * will drop the last refcount but it must take care to flush
172 	 * any secondary tlb before doing the final free on the
173 	 * page. Pages will no longer be referenced by the linux
174 	 * address space but may still be referenced by sptes until
175 	 * the last refcount is dropped.
176 	 *
177 	 * If blockable argument is set to false then the callback cannot
178 	 * sleep and has to return with -EAGAIN if sleeping would be required.
179 	 * 0 should be returned otherwise. Please note that notifiers that can
180 	 * fail invalidate_range_start are not allowed to implement
181 	 * invalidate_range_end, as there is no mechanism for informing the
182 	 * notifier that its start failed.
183 	 */
184 	int (*invalidate_range_start)(struct mmu_notifier *subscription,
185 				      const struct mmu_notifier_range *range);
186 	void (*invalidate_range_end)(struct mmu_notifier *subscription,
187 				     const struct mmu_notifier_range *range);
188 
189 	/*
190 	 * arch_invalidate_secondary_tlbs() is used to manage a non-CPU TLB
191 	 * which shares page-tables with the CPU. The
192 	 * invalidate_range_start()/end() callbacks should not be implemented as
193 	 * invalidate_secondary_tlbs() already catches the points in time when
194 	 * an external TLB needs to be flushed.
195 	 *
196 	 * This requires arch_invalidate_secondary_tlbs() to be called while
197 	 * holding the ptl spin-lock and therefore this callback is not allowed
198 	 * to sleep.
199 	 *
200 	 * This is called by architecture code whenever invalidating a TLB
201 	 * entry. It is assumed that any secondary TLB has the same rules for
202 	 * when invalidations are required. If this is not the case architecture
203 	 * code will need to call this explicitly when required for secondary
204 	 * TLB invalidation.
205 	 */
206 	void (*arch_invalidate_secondary_tlbs)(
207 					struct mmu_notifier *subscription,
208 					struct mm_struct *mm,
209 					unsigned long start,
210 					unsigned long end);
211 
212 	/*
213 	 * These callbacks are used with the get/put interface to manage the
214 	 * lifetime of the mmu_notifier memory. alloc_notifier() returns a new
215 	 * notifier for use with the mm.
216 	 *
217 	 * free_notifier() is only called after the mmu_notifier has been
218 	 * fully put, calls to any ops callback are prevented and no ops
219 	 * callbacks are currently running. It is called from a SRCU callback
220 	 * and cannot sleep.
221 	 */
222 	struct mmu_notifier *(*alloc_notifier)(struct mm_struct *mm);
223 	void (*free_notifier)(struct mmu_notifier *subscription);
224 };
225 
226 /*
227  * The notifier chains are protected by mmap_lock and/or the reverse map
228  * semaphores. Notifier chains are only changed when all reverse maps and
229  * the mmap_lock locks are taken.
230  *
231  * Therefore notifier chains can only be traversed when either
232  *
233  * 1. mmap_lock is held.
234  * 2. One of the reverse map locks is held (i_mmap_rwsem or anon_vma->rwsem).
235  * 3. No other concurrent thread can access the list (release)
236  */
237 struct mmu_notifier {
238 	struct hlist_node hlist;
239 	const struct mmu_notifier_ops *ops;
240 	struct mm_struct *mm;
241 	struct rcu_head rcu;
242 	unsigned int users;
243 };
244 
245 /**
246  * struct mmu_interval_notifier_ops
247  * @invalidate: Upon return the caller must stop using any SPTEs within this
248  *              range. This function can sleep. Return false only if sleeping
249  *              was required but mmu_notifier_range_blockable(range) is false.
250  */
251 struct mmu_interval_notifier_ops {
252 	bool (*invalidate)(struct mmu_interval_notifier *interval_sub,
253 			   const struct mmu_notifier_range *range,
254 			   unsigned long cur_seq);
255 };
256 
257 struct mmu_interval_notifier {
258 	struct interval_tree_node interval_tree;
259 	const struct mmu_interval_notifier_ops *ops;
260 	struct mm_struct *mm;
261 	struct hlist_node deferred_item;
262 	unsigned long invalidate_seq;
263 };
264 
265 #ifdef CONFIG_MMU_NOTIFIER
266 
267 #ifdef CONFIG_LOCKDEP
268 extern struct lockdep_map __mmu_notifier_invalidate_range_start_map;
269 #endif
270 
271 struct mmu_notifier_range {
272 	struct mm_struct *mm;
273 	unsigned long start;
274 	unsigned long end;
275 	unsigned flags;
276 	enum mmu_notifier_event event;
277 	void *owner;
278 };
279 
mm_has_notifiers(struct mm_struct * mm)280 static inline int mm_has_notifiers(struct mm_struct *mm)
281 {
282 	return unlikely(mm->notifier_subscriptions);
283 }
284 
285 struct mmu_notifier *mmu_notifier_get_locked(const struct mmu_notifier_ops *ops,
286 					     struct mm_struct *mm);
287 static inline struct mmu_notifier *
mmu_notifier_get(const struct mmu_notifier_ops * ops,struct mm_struct * mm)288 mmu_notifier_get(const struct mmu_notifier_ops *ops, struct mm_struct *mm)
289 {
290 	struct mmu_notifier *ret;
291 
292 	mmap_write_lock(mm);
293 	ret = mmu_notifier_get_locked(ops, mm);
294 	mmap_write_unlock(mm);
295 	return ret;
296 }
297 void mmu_notifier_put(struct mmu_notifier *subscription);
298 void mmu_notifier_synchronize(void);
299 
300 extern int mmu_notifier_register(struct mmu_notifier *subscription,
301 				 struct mm_struct *mm);
302 extern int __mmu_notifier_register(struct mmu_notifier *subscription,
303 				   struct mm_struct *mm);
304 extern void mmu_notifier_unregister(struct mmu_notifier *subscription,
305 				    struct mm_struct *mm);
306 
307 unsigned long
308 mmu_interval_read_begin(struct mmu_interval_notifier *interval_sub);
309 int mmu_interval_notifier_insert(struct mmu_interval_notifier *interval_sub,
310 				 struct mm_struct *mm, unsigned long start,
311 				 unsigned long length,
312 				 const struct mmu_interval_notifier_ops *ops);
313 int mmu_interval_notifier_insert_locked(
314 	struct mmu_interval_notifier *interval_sub, struct mm_struct *mm,
315 	unsigned long start, unsigned long length,
316 	const struct mmu_interval_notifier_ops *ops);
317 void mmu_interval_notifier_remove(struct mmu_interval_notifier *interval_sub);
318 
319 /**
320  * mmu_interval_set_seq - Save the invalidation sequence
321  * @interval_sub - The subscription passed to invalidate
322  * @cur_seq - The cur_seq passed to the invalidate() callback
323  *
324  * This must be called unconditionally from the invalidate callback of a
325  * struct mmu_interval_notifier_ops under the same lock that is used to call
326  * mmu_interval_read_retry(). It updates the sequence number for later use by
327  * mmu_interval_read_retry(). The provided cur_seq will always be odd.
328  *
329  * If the caller does not call mmu_interval_read_begin() or
330  * mmu_interval_read_retry() then this call is not required.
331  */
332 static inline void
mmu_interval_set_seq(struct mmu_interval_notifier * interval_sub,unsigned long cur_seq)333 mmu_interval_set_seq(struct mmu_interval_notifier *interval_sub,
334 		     unsigned long cur_seq)
335 {
336 	WRITE_ONCE(interval_sub->invalidate_seq, cur_seq);
337 }
338 
339 /**
340  * mmu_interval_read_retry - End a read side critical section against a VA range
341  * interval_sub: The subscription
342  * seq: The return of the paired mmu_interval_read_begin()
343  *
344  * This MUST be called under a user provided lock that is also held
345  * unconditionally by op->invalidate() when it calls mmu_interval_set_seq().
346  *
347  * Each call should be paired with a single mmu_interval_read_begin() and
348  * should be used to conclude the read side.
349  *
350  * Returns true if an invalidation collided with this critical section, and
351  * the caller should retry.
352  */
353 static inline bool
mmu_interval_read_retry(struct mmu_interval_notifier * interval_sub,unsigned long seq)354 mmu_interval_read_retry(struct mmu_interval_notifier *interval_sub,
355 			unsigned long seq)
356 {
357 	return interval_sub->invalidate_seq != seq;
358 }
359 
360 /**
361  * mmu_interval_check_retry - Test if a collision has occurred
362  * interval_sub: The subscription
363  * seq: The return of the matching mmu_interval_read_begin()
364  *
365  * This can be used in the critical section between mmu_interval_read_begin()
366  * and mmu_interval_read_retry().  A return of true indicates an invalidation
367  * has collided with this critical region and a future
368  * mmu_interval_read_retry() will return true.
369  *
370  * False is not reliable and only suggests a collision may not have
371  * occurred. It can be called many times and does not have to hold the user
372  * provided lock.
373  *
374  * This call can be used as part of loops and other expensive operations to
375  * expedite a retry.
376  */
377 static inline bool
mmu_interval_check_retry(struct mmu_interval_notifier * interval_sub,unsigned long seq)378 mmu_interval_check_retry(struct mmu_interval_notifier *interval_sub,
379 			 unsigned long seq)
380 {
381 	/* Pairs with the WRITE_ONCE in mmu_interval_set_seq() */
382 	return READ_ONCE(interval_sub->invalidate_seq) != seq;
383 }
384 
385 extern void __mmu_notifier_subscriptions_destroy(struct mm_struct *mm);
386 extern void __mmu_notifier_release(struct mm_struct *mm);
387 extern int __mmu_notifier_clear_flush_young(struct mm_struct *mm,
388 					  unsigned long start,
389 					  unsigned long end);
390 extern int __mmu_notifier_clear_young(struct mm_struct *mm,
391 				      unsigned long start,
392 				      unsigned long end);
393 extern int __mmu_notifier_test_young(struct mm_struct *mm,
394 				     unsigned long address);
395 extern void __mmu_notifier_change_pte(struct mm_struct *mm,
396 				      unsigned long address, pte_t pte);
397 extern int __mmu_notifier_invalidate_range_start(struct mmu_notifier_range *r);
398 extern void __mmu_notifier_invalidate_range_end(struct mmu_notifier_range *r);
399 extern void __mmu_notifier_arch_invalidate_secondary_tlbs(struct mm_struct *mm,
400 					unsigned long start, unsigned long end);
401 extern bool
402 mmu_notifier_range_update_to_read_only(const struct mmu_notifier_range *range);
403 
404 static inline bool
mmu_notifier_range_blockable(const struct mmu_notifier_range * range)405 mmu_notifier_range_blockable(const struct mmu_notifier_range *range)
406 {
407 	return (range->flags & MMU_NOTIFIER_RANGE_BLOCKABLE);
408 }
409 
mmu_notifier_release(struct mm_struct * mm)410 static inline void mmu_notifier_release(struct mm_struct *mm)
411 {
412 	if (mm_has_notifiers(mm))
413 		__mmu_notifier_release(mm);
414 }
415 
mmu_notifier_clear_flush_young(struct mm_struct * mm,unsigned long start,unsigned long end)416 static inline int mmu_notifier_clear_flush_young(struct mm_struct *mm,
417 					  unsigned long start,
418 					  unsigned long end)
419 {
420 	if (mm_has_notifiers(mm))
421 		return __mmu_notifier_clear_flush_young(mm, start, end);
422 	return 0;
423 }
424 
mmu_notifier_clear_young(struct mm_struct * mm,unsigned long start,unsigned long end)425 static inline int mmu_notifier_clear_young(struct mm_struct *mm,
426 					   unsigned long start,
427 					   unsigned long end)
428 {
429 	if (mm_has_notifiers(mm))
430 		return __mmu_notifier_clear_young(mm, start, end);
431 	return 0;
432 }
433 
mmu_notifier_test_young(struct mm_struct * mm,unsigned long address)434 static inline int mmu_notifier_test_young(struct mm_struct *mm,
435 					  unsigned long address)
436 {
437 	if (mm_has_notifiers(mm))
438 		return __mmu_notifier_test_young(mm, address);
439 	return 0;
440 }
441 
mmu_notifier_change_pte(struct mm_struct * mm,unsigned long address,pte_t pte)442 static inline void mmu_notifier_change_pte(struct mm_struct *mm,
443 					   unsigned long address, pte_t pte)
444 {
445 	if (mm_has_notifiers(mm))
446 		__mmu_notifier_change_pte(mm, address, pte);
447 }
448 
449 static inline void
mmu_notifier_invalidate_range_start(struct mmu_notifier_range * range)450 mmu_notifier_invalidate_range_start(struct mmu_notifier_range *range)
451 {
452 	might_sleep();
453 
454 	lock_map_acquire(&__mmu_notifier_invalidate_range_start_map);
455 	if (mm_has_notifiers(range->mm)) {
456 		range->flags |= MMU_NOTIFIER_RANGE_BLOCKABLE;
457 		__mmu_notifier_invalidate_range_start(range);
458 	}
459 	lock_map_release(&__mmu_notifier_invalidate_range_start_map);
460 }
461 
462 static inline int
mmu_notifier_invalidate_range_start_nonblock(struct mmu_notifier_range * range)463 mmu_notifier_invalidate_range_start_nonblock(struct mmu_notifier_range *range)
464 {
465 	int ret = 0;
466 
467 	lock_map_acquire(&__mmu_notifier_invalidate_range_start_map);
468 	if (mm_has_notifiers(range->mm)) {
469 		range->flags &= ~MMU_NOTIFIER_RANGE_BLOCKABLE;
470 		ret = __mmu_notifier_invalidate_range_start(range);
471 	}
472 	lock_map_release(&__mmu_notifier_invalidate_range_start_map);
473 	return ret;
474 }
475 
476 static inline void
mmu_notifier_invalidate_range_end(struct mmu_notifier_range * range)477 mmu_notifier_invalidate_range_end(struct mmu_notifier_range *range)
478 {
479 	if (mmu_notifier_range_blockable(range))
480 		might_sleep();
481 
482 	if (mm_has_notifiers(range->mm))
483 		__mmu_notifier_invalidate_range_end(range);
484 }
485 
mmu_notifier_arch_invalidate_secondary_tlbs(struct mm_struct * mm,unsigned long start,unsigned long end)486 static inline void mmu_notifier_arch_invalidate_secondary_tlbs(struct mm_struct *mm,
487 					unsigned long start, unsigned long end)
488 {
489 	if (mm_has_notifiers(mm))
490 		__mmu_notifier_arch_invalidate_secondary_tlbs(mm, start, end);
491 }
492 
mmu_notifier_subscriptions_init(struct mm_struct * mm)493 static inline void mmu_notifier_subscriptions_init(struct mm_struct *mm)
494 {
495 	mm->notifier_subscriptions = NULL;
496 }
497 
mmu_notifier_subscriptions_destroy(struct mm_struct * mm)498 static inline void mmu_notifier_subscriptions_destroy(struct mm_struct *mm)
499 {
500 	if (mm_has_notifiers(mm))
501 		__mmu_notifier_subscriptions_destroy(mm);
502 }
503 
504 
mmu_notifier_range_init(struct mmu_notifier_range * range,enum mmu_notifier_event event,unsigned flags,struct mm_struct * mm,unsigned long start,unsigned long end)505 static inline void mmu_notifier_range_init(struct mmu_notifier_range *range,
506 					   enum mmu_notifier_event event,
507 					   unsigned flags,
508 					   struct mm_struct *mm,
509 					   unsigned long start,
510 					   unsigned long end)
511 {
512 	range->event = event;
513 	range->mm = mm;
514 	range->start = start;
515 	range->end = end;
516 	range->flags = flags;
517 }
518 
mmu_notifier_range_init_owner(struct mmu_notifier_range * range,enum mmu_notifier_event event,unsigned int flags,struct mm_struct * mm,unsigned long start,unsigned long end,void * owner)519 static inline void mmu_notifier_range_init_owner(
520 			struct mmu_notifier_range *range,
521 			enum mmu_notifier_event event, unsigned int flags,
522 			struct mm_struct *mm, unsigned long start,
523 			unsigned long end, void *owner)
524 {
525 	mmu_notifier_range_init(range, event, flags, mm, start, end);
526 	range->owner = owner;
527 }
528 
529 #define ptep_clear_flush_young_notify(__vma, __address, __ptep)		\
530 ({									\
531 	int __young;							\
532 	struct vm_area_struct *___vma = __vma;				\
533 	unsigned long ___address = __address;				\
534 	__young = ptep_clear_flush_young(___vma, ___address, __ptep);	\
535 	__young |= mmu_notifier_clear_flush_young(___vma->vm_mm,	\
536 						  ___address,		\
537 						  ___address +		\
538 							PAGE_SIZE);	\
539 	__young;							\
540 })
541 
542 #define pmdp_clear_flush_young_notify(__vma, __address, __pmdp)		\
543 ({									\
544 	int __young;							\
545 	struct vm_area_struct *___vma = __vma;				\
546 	unsigned long ___address = __address;				\
547 	__young = pmdp_clear_flush_young(___vma, ___address, __pmdp);	\
548 	__young |= mmu_notifier_clear_flush_young(___vma->vm_mm,	\
549 						  ___address,		\
550 						  ___address +		\
551 							PMD_SIZE);	\
552 	__young;							\
553 })
554 
555 #define ptep_clear_young_notify(__vma, __address, __ptep)		\
556 ({									\
557 	int __young;							\
558 	struct vm_area_struct *___vma = __vma;				\
559 	unsigned long ___address = __address;				\
560 	__young = ptep_test_and_clear_young(___vma, ___address, __ptep);\
561 	__young |= mmu_notifier_clear_young(___vma->vm_mm, ___address,	\
562 					    ___address + PAGE_SIZE);	\
563 	__young;							\
564 })
565 
566 #define pmdp_clear_young_notify(__vma, __address, __pmdp)		\
567 ({									\
568 	int __young;							\
569 	struct vm_area_struct *___vma = __vma;				\
570 	unsigned long ___address = __address;				\
571 	__young = pmdp_test_and_clear_young(___vma, ___address, __pmdp);\
572 	__young |= mmu_notifier_clear_young(___vma->vm_mm, ___address,	\
573 					    ___address + PMD_SIZE);	\
574 	__young;							\
575 })
576 
577 /*
578  * set_pte_at_notify() sets the pte _after_ running the notifier.
579  * This is safe to start by updating the secondary MMUs, because the primary MMU
580  * pte invalidate must have already happened with a ptep_clear_flush() before
581  * set_pte_at_notify() has been invoked.  Updating the secondary MMUs first is
582  * required when we change both the protection of the mapping from read-only to
583  * read-write and the pfn (like during copy on write page faults). Otherwise the
584  * old page would remain mapped readonly in the secondary MMUs after the new
585  * page is already writable by some CPU through the primary MMU.
586  */
587 #define set_pte_at_notify(__mm, __address, __ptep, __pte)		\
588 ({									\
589 	struct mm_struct *___mm = __mm;					\
590 	unsigned long ___address = __address;				\
591 	pte_t ___pte = __pte;						\
592 									\
593 	mmu_notifier_change_pte(___mm, ___address, ___pte);		\
594 	set_pte_at(___mm, ___address, __ptep, ___pte);			\
595 })
596 
597 #else /* CONFIG_MMU_NOTIFIER */
598 
599 struct mmu_notifier_range {
600 	unsigned long start;
601 	unsigned long end;
602 };
603 
_mmu_notifier_range_init(struct mmu_notifier_range * range,unsigned long start,unsigned long end)604 static inline void _mmu_notifier_range_init(struct mmu_notifier_range *range,
605 					    unsigned long start,
606 					    unsigned long end)
607 {
608 	range->start = start;
609 	range->end = end;
610 }
611 
612 #define mmu_notifier_range_init(range,event,flags,mm,start,end)  \
613 	_mmu_notifier_range_init(range, start, end)
614 #define mmu_notifier_range_init_owner(range, event, flags, mm, start, \
615 					end, owner) \
616 	_mmu_notifier_range_init(range, start, end)
617 
618 static inline bool
mmu_notifier_range_blockable(const struct mmu_notifier_range * range)619 mmu_notifier_range_blockable(const struct mmu_notifier_range *range)
620 {
621 	return true;
622 }
623 
mm_has_notifiers(struct mm_struct * mm)624 static inline int mm_has_notifiers(struct mm_struct *mm)
625 {
626 	return 0;
627 }
628 
mmu_notifier_release(struct mm_struct * mm)629 static inline void mmu_notifier_release(struct mm_struct *mm)
630 {
631 }
632 
mmu_notifier_clear_flush_young(struct mm_struct * mm,unsigned long start,unsigned long end)633 static inline int mmu_notifier_clear_flush_young(struct mm_struct *mm,
634 					  unsigned long start,
635 					  unsigned long end)
636 {
637 	return 0;
638 }
639 
mmu_notifier_test_young(struct mm_struct * mm,unsigned long address)640 static inline int mmu_notifier_test_young(struct mm_struct *mm,
641 					  unsigned long address)
642 {
643 	return 0;
644 }
645 
mmu_notifier_change_pte(struct mm_struct * mm,unsigned long address,pte_t pte)646 static inline void mmu_notifier_change_pte(struct mm_struct *mm,
647 					   unsigned long address, pte_t pte)
648 {
649 }
650 
651 static inline void
mmu_notifier_invalidate_range_start(struct mmu_notifier_range * range)652 mmu_notifier_invalidate_range_start(struct mmu_notifier_range *range)
653 {
654 }
655 
656 static inline int
mmu_notifier_invalidate_range_start_nonblock(struct mmu_notifier_range * range)657 mmu_notifier_invalidate_range_start_nonblock(struct mmu_notifier_range *range)
658 {
659 	return 0;
660 }
661 
662 static inline
mmu_notifier_invalidate_range_end(struct mmu_notifier_range * range)663 void mmu_notifier_invalidate_range_end(struct mmu_notifier_range *range)
664 {
665 }
666 
mmu_notifier_arch_invalidate_secondary_tlbs(struct mm_struct * mm,unsigned long start,unsigned long end)667 static inline void mmu_notifier_arch_invalidate_secondary_tlbs(struct mm_struct *mm,
668 				  unsigned long start, unsigned long end)
669 {
670 }
671 
mmu_notifier_subscriptions_init(struct mm_struct * mm)672 static inline void mmu_notifier_subscriptions_init(struct mm_struct *mm)
673 {
674 }
675 
mmu_notifier_subscriptions_destroy(struct mm_struct * mm)676 static inline void mmu_notifier_subscriptions_destroy(struct mm_struct *mm)
677 {
678 }
679 
680 #define mmu_notifier_range_update_to_read_only(r) false
681 
682 #define ptep_clear_flush_young_notify ptep_clear_flush_young
683 #define pmdp_clear_flush_young_notify pmdp_clear_flush_young
684 #define ptep_clear_young_notify ptep_test_and_clear_young
685 #define pmdp_clear_young_notify pmdp_test_and_clear_young
686 #define	ptep_clear_flush_notify ptep_clear_flush
687 #define pmdp_huge_clear_flush_notify pmdp_huge_clear_flush
688 #define pudp_huge_clear_flush_notify pudp_huge_clear_flush
689 #define set_pte_at_notify set_pte_at
690 
mmu_notifier_synchronize(void)691 static inline void mmu_notifier_synchronize(void)
692 {
693 }
694 
695 #endif /* CONFIG_MMU_NOTIFIER */
696 
697 #endif /* _LINUX_MMU_NOTIFIER_H */
698