include/linux/mmu_notifier.h

   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 dirtyness 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  * migrate_pgmap_owner field matches the driver's device private pgmap owner.
  45  */
  46 enum mmu_notifier_event {
  47         MMU_NOTIFY_UNMAP = 0,
  48         MMU_NOTIFY_CLEAR,
  49         MMU_NOTIFY_PROTECTION_VMA,
  50         MMU_NOTIFY_PROTECTION_PAGE,
  51         MMU_NOTIFY_SOFT_DIRTY,
  52         MMU_NOTIFY_RELEASE,
  53         MMU_NOTIFY_MIGRATE,
  54 };
  55
  56 #define MMU_NOTIFIER_RANGE_BLOCKABLE (1 << 0)
  57
  58 struct mmu_notifier_ops {
  59         /*
  60          * Called either by mmu_notifier_unregister or when the mm is
  61          * being destroyed by exit_mmap, always before all pages are
  62          * freed. This can run concurrently with other mmu notifier
  63          * methods (the ones invoked outside the mm context) and it
  64          * should tear down all secondary mmu mappings and freeze the
  65          * secondary mmu. If this method isn't implemented you've to
  66          * be sure that nothing could possibly write to the pages
  67          * through the secondary mmu by the time the last thread with
  68          * tsk->mm == mm exits.
  69          *
  70          * As side note: the pages freed after ->release returns could
  71          * be immediately reallocated by the gart at an alias physical
  72          * address with a different cache model, so if ->release isn't
  73          * implemented because all _software_ driven memory accesses
  74          * through the secondary mmu are terminated by the time the
  75          * last thread of this mm quits, you've also to be sure that
  76          * speculative _hardware_ operations can't allocate dirty
  77          * cachelines in the cpu that could not be snooped and made
  78          * coherent with the other read and write operations happening
  79          * through the gart alias address, so leading to memory
  80          * corruption.
  81          */
  82         void (*release)(struct mmu_notifier *subscription,
  83                         struct mm_struct *mm);
  84
  85         /*
  86          * clear_flush_young is called after the VM is
  87          * test-and-clearing the young/accessed bitflag in the
  88          * pte. This way the VM will provide proper aging to the
  89          * accesses to the page through the secondary MMUs and not
  90          * only to the ones through the Linux pte.
  91          * Start-end is necessary in case the secondary MMU is mapping the page
  92          * at a smaller granularity than the primary MMU.
  93          */
  94         int (*clear_flush_young)(struct mmu_notifier *subscription,
  95                                  struct mm_struct *mm,
  96                                  unsigned long start,
  97                                  unsigned long end);
  98
  99         /*
 100          * clear_young is a lightweight version of clear_flush_young. Like the
 101          * latter, it is supposed to test-and-clear the young/accessed bitflag
 102          * in the secondary pte, but it may omit flushing the secondary tlb.
 103          */
 104         int (*clear_young)(struct mmu_notifier *subscription,
 105                            struct mm_struct *mm,
 106                            unsigned long start,
 107                            unsigned long end);
 108
 109         /*
 110          * test_young is called to check the young/accessed bitflag in
 111          * the secondary pte. This is used to know if the page is
 112          * frequently used without actually clearing the flag or tearing
 113          * down the secondary mapping on the page.
 114          */
 115         int (*test_young)(struct mmu_notifier *subscription,
 116                           struct mm_struct *mm,
 117                           unsigned long address);
 118
 119         /*
 120          * change_pte is called in cases that pte mapping to page is changed:
 121          * for example, when ksm remaps pte to point to a new shared page.
 122          */
 123         void (*change_pte)(struct mmu_notifier *subscription,
 124                            struct mm_struct *mm,
 125                            unsigned long address,
 126                            pte_t pte);
 127
 128         /*
 129          * invalidate_range_start() and invalidate_range_end() must be
 130          * paired and are called only when the mmap_lock and/or the
 131          * locks protecting the reverse maps are held. If the subsystem
 132          * can't guarantee that no additional references are taken to
 133          * the pages in the range, it has to implement the
 134          * invalidate_range() notifier to remove any references taken
 135          * after invalidate_range_start().
 136          *
 137          * Invalidation of multiple concurrent ranges may be
 138          * optionally permitted by the driver. Either way the
 139          * establishment of sptes is forbidden in the range passed to
 140          * invalidate_range_begin/end for the whole duration of the
 141          * invalidate_range_begin/end critical section.
 142          *
 143          * invalidate_range_start() is called when all pages in the
 144          * range are still mapped and have at least a refcount of one.
 145          *
 146          * invalidate_range_end() is called when all pages in the
 147          * range have been unmapped and the pages have been freed by
 148          * the VM.
 149          *
 150          * The VM will remove the page table entries and potentially
 151          * the page between invalidate_range_start() and
 152          * invalidate_range_end(). If the page must not be freed
 153          * because of pending I/O or other circumstances then the
 154          * invalidate_range_start() callback (or the initial mapping
 155          * by the driver) must make sure that the refcount is kept
 156          * elevated.
 157          *
 158          * If the driver increases the refcount when the pages are
 159          * initially mapped into an address space then either
 160          * invalidate_range_start() or invalidate_range_end() may
 161          * decrease the refcount. If the refcount is decreased on
 162          * invalidate_range_start() then the VM can free pages as page
 163          * table entries are removed.  If the refcount is only
 164          * droppped on invalidate_range_end() then the driver itself
 165          * will drop the last refcount but it must take care to flush
 166          * any secondary tlb before doing the final free on the
 167          * page. Pages will no longer be referenced by the linux
 168          * address space but may still be referenced by sptes until
 169          * the last refcount is dropped.
 170          *
 171          * If blockable argument is set to false then the callback cannot
 172          * sleep and has to return with -EAGAIN. 0 should be returned
 173          * otherwise. Please note that if invalidate_range_start approves
 174          * a non-blocking behavior then the same applies to
 175          * invalidate_range_end.
 176          *
 177          */
 178         int (*invalidate_range_start)(struct mmu_notifier *subscription,
 179                                       const struct mmu_notifier_range *range);
 180         void (*invalidate_range_end)(struct mmu_notifier *subscription,
 181                                      const struct mmu_notifier_range *range);
 182
 183         /*
 184          * invalidate_range() is either called between
 185          * invalidate_range_start() and invalidate_range_end() when the
 186          * VM has to free pages that where unmapped, but before the
 187          * pages are actually freed, or outside of _start()/_end() when
 188          * a (remote) TLB is necessary.
 189          *
 190          * If invalidate_range() is used to manage a non-CPU TLB with
 191          * shared page-tables, it not necessary to implement the
 192          * invalidate_range_start()/end() notifiers, as
 193          * invalidate_range() alread catches the points in time when an
 194          * external TLB range needs to be flushed. For more in depth
 195          * discussion on this see Documentation/vm/mmu_notifier.rst
 196          *
 197          * Note that this function might be called with just a sub-range
 198          * of what was passed to invalidate_range_start()/end(), if
 199          * called between those functions.
 200          */
 201         void (*invalidate_range)(struct mmu_notifier *subscription,
 202                                  struct mm_struct *mm,
 203                                  unsigned long start,
 204                                  unsigned long end);
 205
 206         /*
 207          * These callbacks are used with the get/put interface to manage the
 208          * lifetime of the mmu_notifier memory. alloc_notifier() returns a new
 209          * notifier for use with the mm.
 210          *
 211          * free_notifier() is only called after the mmu_notifier has been
 212          * fully put, calls to any ops callback are prevented and no ops
 213          * callbacks are currently running. It is called from a SRCU callback
 214          * and cannot sleep.
 215          */
 216         struct mmu_notifier *(*alloc_notifier)(struct mm_struct *mm);
 217         void (*free_notifier)(struct mmu_notifier *subscription);
 218 };
 219
 220 /*
 221  * The notifier chains are protected by mmap_lock and/or the reverse map
 222  * semaphores. Notifier chains are only changed when all reverse maps and
 223  * the mmap_lock locks are taken.
 224  *
 225  * Therefore notifier chains can only be traversed when either
 226  *
 227  * 1. mmap_lock is held.
 228  * 2. One of the reverse map locks is held (i_mmap_rwsem or anon_vma->rwsem).
 229  * 3. No other concurrent thread can access the list (release)
 230  */
 231 struct mmu_notifier {
 232         struct hlist_node hlist;
 233         const struct mmu_notifier_ops *ops;
 234         struct mm_struct *mm;
 235         struct rcu_head rcu;
 236         unsigned int users;
 237 };
 238
 239 /**
 240  * struct mmu_interval_notifier_ops
 241  * @invalidate: Upon return the caller must stop using any SPTEs within this
 242  *              range. This function can sleep. Return false only if sleeping
 243  *              was required but mmu_notifier_range_blockable(range) is false.
 244  */
 245 struct mmu_interval_notifier_ops {
 246         bool (*invalidate)(struct mmu_interval_notifier *interval_sub,
 247                            const struct mmu_notifier_range *range,
 248                            unsigned long cur_seq);
 249 };
 250
 251 struct mmu_interval_notifier {
 252         struct interval_tree_node interval_tree;
 253         const struct mmu_interval_notifier_ops *ops;
 254         struct mm_struct *mm;
 255         struct hlist_node deferred_item;
 256         unsigned long invalidate_seq;
 257 };
 258
 259 #ifdef CONFIG_MMU_NOTIFIER
 260
 261 #ifdef CONFIG_LOCKDEP
 262 extern struct lockdep_map __mmu_notifier_invalidate_range_start_map;
 263 #endif
 264
 265 struct mmu_notifier_range {
 266         struct vm_area_struct *vma;
 267         struct mm_struct *mm;
 268         unsigned long start;
 269         unsigned long end;
 270         unsigned flags;
 271         enum mmu_notifier_event event;
 272         void *migrate_pgmap_owner;
 273 };
 274
 275 static inline int mm_has_notifiers(struct mm_struct *mm)
 276 {
 277         return unlikely(mm->notifier_subscriptions);
 278 }
 279
 280 struct mmu_notifier *mmu_notifier_get_locked(const struct mmu_notifier_ops *ops,
 281                                              struct mm_struct *mm);
 282 static inline struct mmu_notifier *
 283 mmu_notifier_get(const struct mmu_notifier_ops *ops, struct mm_struct *mm)
 284 {
 285         struct mmu_notifier *ret;
 286
 287         mmap_write_lock(mm);
 288         ret = mmu_notifier_get_locked(ops, mm);
 289         mmap_write_unlock(mm);
 290         return ret;
 291 }
 292 void mmu_notifier_put(struct mmu_notifier *subscription);
 293 void mmu_notifier_synchronize(void);
 294
 295 extern int mmu_notifier_register(struct mmu_notifier *subscription,
 296                                  struct mm_struct *mm);
 297 extern int __mmu_notifier_register(struct mmu_notifier *subscription,
 298                                    struct mm_struct *mm);
 299 extern void mmu_notifier_unregister(struct mmu_notifier *subscription,
 300                                     struct mm_struct *mm);
 301
 302 unsigned long
 303 mmu_interval_read_begin(struct mmu_interval_notifier *interval_sub);
 304 int mmu_interval_notifier_insert(struct mmu_interval_notifier *interval_sub,
 305                                  struct mm_struct *mm, unsigned long start,
 306                                  unsigned long length,
 307                                  const struct mmu_interval_notifier_ops *ops);
 308 int mmu_interval_notifier_insert_locked(
 309         struct mmu_interval_notifier *interval_sub, struct mm_struct *mm,
 310         unsigned long start, unsigned long length,
 311         const struct mmu_interval_notifier_ops *ops);
 312 void mmu_interval_notifier_remove(struct mmu_interval_notifier *interval_sub);
 313
 314 /**
 315  * mmu_interval_set_seq - Save the invalidation sequence
 316  * @interval_sub - The subscription passed to invalidate
 317  * @cur_seq - The cur_seq passed to the invalidate() callback
 318  *
 319  * This must be called unconditionally from the invalidate callback of a
 320  * struct mmu_interval_notifier_ops under the same lock that is used to call
 321  * mmu_interval_read_retry(). It updates the sequence number for later use by
 322  * mmu_interval_read_retry(). The provided cur_seq will always be odd.
 323  *
 324  * If the caller does not call mmu_interval_read_begin() or
 325  * mmu_interval_read_retry() then this call is not required.
 326  */
 327 static inline void
 328 mmu_interval_set_seq(struct mmu_interval_notifier *interval_sub,
 329                      unsigned long cur_seq)
 330 {
 331         WRITE_ONCE(interval_sub->invalidate_seq, cur_seq);
 332 }
 333
 334 /**
 335  * mmu_interval_read_retry - End a read side critical section against a VA range
 336  * interval_sub: The subscription
 337  * seq: The return of the paired mmu_interval_read_begin()
 338  *
 339  * This MUST be called under a user provided lock that is also held
 340  * unconditionally by op->invalidate() when it calls mmu_interval_set_seq().
 341  *
 342  * Each call should be paired with a single mmu_interval_read_begin() and
 343  * should be used to conclude the read side.
 344  *
 345  * Returns true if an invalidation collided with this critical section, and
 346  * the caller should retry.
 347  */
 348 static inline bool
 349 mmu_interval_read_retry(struct mmu_interval_notifier *interval_sub,
 350                         unsigned long seq)
 351 {
 352         return interval_sub->invalidate_seq != seq;
 353 }
 354
 355 /**
 356  * mmu_interval_check_retry - Test if a collision has occurred
 357  * interval_sub: The subscription
 358  * seq: The return of the matching mmu_interval_read_begin()
 359  *
 360  * This can be used in the critical section between mmu_interval_read_begin()
 361  * and mmu_interval_read_retry().  A return of true indicates an invalidation
 362  * has collided with this critical region and a future
 363  * mmu_interval_read_retry() will return true.
 364  *
 365  * False is not reliable and only suggests a collision may not have
 366  * occured. It can be called many times and does not have to hold the user
 367  * provided lock.
 368  *
 369  * This call can be used as part of loops and other expensive operations to
 370  * expedite a retry.
 371  */
 372 static inline bool
 373 mmu_interval_check_retry(struct mmu_interval_notifier *interval_sub,
 374                          unsigned long seq)
 375 {
 376         /* Pairs with the WRITE_ONCE in mmu_interval_set_seq() */
 377         return READ_ONCE(interval_sub->invalidate_seq) != seq;
 378 }
 379
 380 extern void __mmu_notifier_subscriptions_destroy(struct mm_struct *mm);
 381 extern void __mmu_notifier_release(struct mm_struct *mm);
 382 extern int __mmu_notifier_clear_flush_young(struct mm_struct *mm,
 383                                           unsigned long start,
 384                                           unsigned long end);
 385 extern int __mmu_notifier_clear_young(struct mm_struct *mm,
 386                                       unsigned long start,
 387                                       unsigned long end);
 388 extern int __mmu_notifier_test_young(struct mm_struct *mm,
 389                                      unsigned long address);
 390 extern void __mmu_notifier_change_pte(struct mm_struct *mm,
 391                                       unsigned long address, pte_t pte);
 392 extern int __mmu_notifier_invalidate_range_start(struct mmu_notifier_range *r);
 393 extern void __mmu_notifier_invalidate_range_end(struct mmu_notifier_range *r,
 394                                   bool only_end);
 395 extern void __mmu_notifier_invalidate_range(struct mm_struct *mm,
 396                                   unsigned long start, unsigned long end);
 397 extern bool
 398 mmu_notifier_range_update_to_read_only(const struct mmu_notifier_range *range);
 399
 400 static inline bool
 401 mmu_notifier_range_blockable(const struct mmu_notifier_range *range)
 402 {
 403         return (range->flags & MMU_NOTIFIER_RANGE_BLOCKABLE);
 404 }
 405
 406 static inline void mmu_notifier_release(struct mm_struct *mm)
 407 {
 408         if (mm_has_notifiers(mm))
 409                 __mmu_notifier_release(mm);
 410 }
 411
 412 static inline int mmu_notifier_clear_flush_young(struct mm_struct *mm,
 413                                           unsigned long start,
 414                                           unsigned long end)
 415 {
 416         if (mm_has_notifiers(mm))
 417                 return __mmu_notifier_clear_flush_young(mm, start, end);
 418         return 0;
 419 }
 420
 421 static inline int mmu_notifier_clear_young(struct mm_struct *mm,
 422                                            unsigned long start,
 423                                            unsigned long end)
 424 {
 425         if (mm_has_notifiers(mm))
 426                 return __mmu_notifier_clear_young(mm, start, end);
 427         return 0;
 428 }
 429
 430 static inline int mmu_notifier_test_young(struct mm_struct *mm,
 431                                           unsigned long address)
 432 {
 433         if (mm_has_notifiers(mm))
 434                 return __mmu_notifier_test_young(mm, address);
 435         return 0;
 436 }
 437
 438 static inline void mmu_notifier_change_pte(struct mm_struct *mm,
 439                                            unsigned long address, pte_t pte)
 440 {
 441         if (mm_has_notifiers(mm))
 442                 __mmu_notifier_change_pte(mm, address, pte);
 443 }
 444
 445 static inline void
 446 mmu_notifier_invalidate_range_start(struct mmu_notifier_range *range)
 447 {
 448         might_sleep();
 449
 450         lock_map_acquire(&__mmu_notifier_invalidate_range_start_map);
 451         if (mm_has_notifiers(range->mm)) {
 452                 range->flags |= MMU_NOTIFIER_RANGE_BLOCKABLE;
 453                 __mmu_notifier_invalidate_range_start(range);
 454         }
 455         lock_map_release(&__mmu_notifier_invalidate_range_start_map);
 456 }
 457
 458 static inline int
 459 mmu_notifier_invalidate_range_start_nonblock(struct mmu_notifier_range *range)
 460 {
 461         int ret = 0;
 462
 463         lock_map_acquire(&__mmu_notifier_invalidate_range_start_map);
 464         if (mm_has_notifiers(range->mm)) {
 465                 range->flags &= ~MMU_NOTIFIER_RANGE_BLOCKABLE;
 466                 ret = __mmu_notifier_invalidate_range_start(range);
 467         }
 468         lock_map_release(&__mmu_notifier_invalidate_range_start_map);
 469         return ret;
 470 }
 471
 472 static inline void
 473 mmu_notifier_invalidate_range_end(struct mmu_notifier_range *range)
 474 {
 475         if (mmu_notifier_range_blockable(range))
 476                 might_sleep();
 477
 478         if (mm_has_notifiers(range->mm))
 479                 __mmu_notifier_invalidate_range_end(range, false);
 480 }
 481
 482 static inline void
 483 mmu_notifier_invalidate_range_only_end(struct mmu_notifier_range *range)
 484 {
 485         if (mm_has_notifiers(range->mm))
 486                 __mmu_notifier_invalidate_range_end(range, true);
 487 }
 488
 489 static inline void mmu_notifier_invalidate_range(struct mm_struct *mm,
 490                                   unsigned long start, unsigned long end)
 491 {
 492         if (mm_has_notifiers(mm))
 493                 __mmu_notifier_invalidate_range(mm, start, end);
 494 }
 495
 496 static inline void mmu_notifier_subscriptions_init(struct mm_struct *mm)
 497 {
 498         mm->notifier_subscriptions = NULL;
 499 }
 500
 501 static inline void mmu_notifier_subscriptions_destroy(struct mm_struct *mm)
 502 {
 503         if (mm_has_notifiers(mm))
 504                 __mmu_notifier_subscriptions_destroy(mm);
 505 }
 506
 507
 508 static inline void mmu_notifier_range_init(struct mmu_notifier_range *range,
 509                                            enum mmu_notifier_event event,
 510                                            unsigned flags,
 511                                            struct vm_area_struct *vma,
 512                                            struct mm_struct *mm,
 513                                            unsigned long start,
 514                                            unsigned long end)
 515 {
 516         range->vma = vma;
 517         range->event = event;
 518         range->mm = mm;
 519         range->start = start;
 520         range->end = end;
 521         range->flags = flags;
 522 }
 523
 524 static inline void mmu_notifier_range_init_migrate(
 525                         struct mmu_notifier_range *range, unsigned int flags,
 526                         struct vm_area_struct *vma, struct mm_struct *mm,
 527                         unsigned long start, unsigned long end, void *pgmap)
 528 {
 529         mmu_notifier_range_init(range, MMU_NOTIFY_MIGRATE, flags, vma, mm,
 530                                 start, end);
 531         range->migrate_pgmap_owner = pgmap;
 532 }
 533
 534 #define ptep_clear_flush_young_notify(__vma, __address, __ptep)         \
 535 ({                                                                      \
 536         int __young;                                                    \
 537         struct vm_area_struct *___vma = __vma;                          \
 538         unsigned long ___address = __address;                           \
 539         __young = ptep_clear_flush_young(___vma, ___address, __ptep);   \
 540         __young |= mmu_notifier_clear_flush_young(___vma->vm_mm,        \
 541                                                   ___address,           \
 542                                                   ___address +          \
 543                                                         PAGE_SIZE);     \
 544         __young;                                                        \
 545 })
 546
 547 #define pmdp_clear_flush_young_notify(__vma, __address, __pmdp)         \
 548 ({                                                                      \
 549         int __young;                                                    \
 550         struct vm_area_struct *___vma = __vma;                          \
 551         unsigned long ___address = __address;                           \
 552         __young = pmdp_clear_flush_young(___vma, ___address, __pmdp);   \
 553         __young |= mmu_notifier_clear_flush_young(___vma->vm_mm,        \
 554                                                   ___address,           \
 555                                                   ___address +          \
 556                                                         PMD_SIZE);      \
 557         __young;                                                        \
 558 })
 559
 560 #define ptep_clear_young_notify(__vma, __address, __ptep)               \
 561 ({                                                                      \
 562         int __young;                                                    \
 563         struct vm_area_struct *___vma = __vma;                          \
 564         unsigned long ___address = __address;                           \
 565         __young = ptep_test_and_clear_young(___vma, ___address, __ptep);\
 566         __young |= mmu_notifier_clear_young(___vma->vm_mm, ___address,  \
 567                                             ___address + PAGE_SIZE);    \
 568         __young;                                                        \
 569 })
 570
 571 #define pmdp_clear_young_notify(__vma, __address, __pmdp)               \
 572 ({                                                                      \
 573         int __young;                                                    \
 574         struct vm_area_struct *___vma = __vma;                          \
 575         unsigned long ___address = __address;                           \
 576         __young = pmdp_test_and_clear_young(___vma, ___address, __pmdp);\
 577         __young |= mmu_notifier_clear_young(___vma->vm_mm, ___address,  \
 578                                             ___address + PMD_SIZE);     \
 579         __young;                                                        \
 580 })
 581
 582 #define ptep_clear_flush_notify(__vma, __address, __ptep)               \
 583 ({                                                                      \
 584         unsigned long ___addr = __address & PAGE_MASK;                  \
 585         struct mm_struct *___mm = (__vma)->vm_mm;                       \
 586         pte_t ___pte;                                                   \
 587                                                                         \
 588         ___pte = ptep_clear_flush(__vma, __address, __ptep);            \
 589         mmu_notifier_invalidate_range(___mm, ___addr,                   \
 590                                         ___addr + PAGE_SIZE);           \
 591                                                                         \
 592         ___pte;                                                         \
 593 })
 594
 595 #define pmdp_huge_clear_flush_notify(__vma, __haddr, __pmd)             \
 596 ({                                                                      \
 597         unsigned long ___haddr = __haddr & HPAGE_PMD_MASK;              \
 598         struct mm_struct *___mm = (__vma)->vm_mm;                       \
 599         pmd_t ___pmd;                                                   \
 600                                                                         \
 601         ___pmd = pmdp_huge_clear_flush(__vma, __haddr, __pmd);          \
 602         mmu_notifier_invalidate_range(___mm, ___haddr,                  \
 603                                       ___haddr + HPAGE_PMD_SIZE);       \
 604                                                                         \
 605         ___pmd;                                                         \
 606 })
 607
 608 #define pudp_huge_clear_flush_notify(__vma, __haddr, __pud)             \
 609 ({                                                                      \
 610         unsigned long ___haddr = __haddr & HPAGE_PUD_MASK;              \
 611         struct mm_struct *___mm = (__vma)->vm_mm;                       \
 612         pud_t ___pud;                                                   \
 613                                                                         \
 614         ___pud = pudp_huge_clear_flush(__vma, __haddr, __pud);          \
 615         mmu_notifier_invalidate_range(___mm, ___haddr,                  \
 616                                       ___haddr + HPAGE_PUD_SIZE);       \
 617                                                                         \
 618         ___pud;                                                         \
 619 })
 620
 621 /*
 622  * set_pte_at_notify() sets the pte _after_ running the notifier.
 623  * This is safe to start by updating the secondary MMUs, because the primary MMU
 624  * pte invalidate must have already happened with a ptep_clear_flush() before
 625  * set_pte_at_notify() has been invoked.  Updating the secondary MMUs first is
 626  * required when we change both the protection of the mapping from read-only to
 627  * read-write and the pfn (like during copy on write page faults). Otherwise the
 628  * old page would remain mapped readonly in the secondary MMUs after the new
 629  * page is already writable by some CPU through the primary MMU.
 630  */
 631 #define set_pte_at_notify(__mm, __address, __ptep, __pte)               \
 632 ({                                                                      \
 633         struct mm_struct *___mm = __mm;                                 \
 634         unsigned long ___address = __address;                           \
 635         pte_t ___pte = __pte;                                           \
 636                                                                         \
 637         mmu_notifier_change_pte(___mm, ___address, ___pte);             \
 638         set_pte_at(___mm, ___address, __ptep, ___pte);                  \
 639 })
 640
 641 #else /* CONFIG_MMU_NOTIFIER */
 642
 643 struct mmu_notifier_range {
 644         unsigned long start;
 645         unsigned long end;
 646 };
 647
 648 static inline void _mmu_notifier_range_init(struct mmu_notifier_range *range,
 649                                             unsigned long start,
 650                                             unsigned long end)
 651 {
 652         range->start = start;
 653         range->end = end;
 654 }
 655
 656 #define mmu_notifier_range_init(range,event,flags,vma,mm,start,end)  \
 657         _mmu_notifier_range_init(range, start, end)
 658 #define mmu_notifier_range_init_migrate(range, flags, vma, mm, start, end, \
 659                                         pgmap) \
 660         _mmu_notifier_range_init(range, start, end)
 661
 662 static inline bool
 663 mmu_notifier_range_blockable(const struct mmu_notifier_range *range)
 664 {
 665         return true;
 666 }
 667
 668 static inline int mm_has_notifiers(struct mm_struct *mm)
 669 {
 670         return 0;
 671 }
 672
 673 static inline void mmu_notifier_release(struct mm_struct *mm)
 674 {
 675 }
 676
 677 static inline int mmu_notifier_clear_flush_young(struct mm_struct *mm,
 678                                           unsigned long start,
 679                                           unsigned long end)
 680 {
 681         return 0;
 682 }
 683
 684 static inline int mmu_notifier_test_young(struct mm_struct *mm,
 685                                           unsigned long address)
 686 {
 687         return 0;
 688 }
 689
 690 static inline void mmu_notifier_change_pte(struct mm_struct *mm,
 691                                            unsigned long address, pte_t pte)
 692 {
 693 }
 694
 695 static inline void
 696 mmu_notifier_invalidate_range_start(struct mmu_notifier_range *range)
 697 {
 698 }
 699
 700 static inline int
 701 mmu_notifier_invalidate_range_start_nonblock(struct mmu_notifier_range *range)
 702 {
 703         return 0;
 704 }
 705
 706 static inline
 707 void mmu_notifier_invalidate_range_end(struct mmu_notifier_range *range)
 708 {
 709 }
 710
 711 static inline void
 712 mmu_notifier_invalidate_range_only_end(struct mmu_notifier_range *range)
 713 {
 714 }
 715
 716 static inline void mmu_notifier_invalidate_range(struct mm_struct *mm,
 717                                   unsigned long start, unsigned long end)
 718 {
 719 }
 720
 721 static inline void mmu_notifier_subscriptions_init(struct mm_struct *mm)
 722 {
 723 }
 724
 725 static inline void mmu_notifier_subscriptions_destroy(struct mm_struct *mm)
 726 {
 727 }
 728
 729 #define mmu_notifier_range_update_to_read_only(r) false
 730
 731 #define ptep_clear_flush_young_notify ptep_clear_flush_young
 732 #define pmdp_clear_flush_young_notify pmdp_clear_flush_young
 733 #define ptep_clear_young_notify ptep_test_and_clear_young
 734 #define pmdp_clear_young_notify pmdp_test_and_clear_young
 735 #define ptep_clear_flush_notify ptep_clear_flush
 736 #define pmdp_huge_clear_flush_notify pmdp_huge_clear_flush
 737 #define pudp_huge_clear_flush_notify pudp_huge_clear_flush
 738 #define set_pte_at_notify set_pte_at
 739
 740 static inline void mmu_notifier_synchronize(void)
 741 {
 742 }
 743
 744 #endif /* CONFIG_MMU_NOTIFIER */
 745
 746 #endif /* _LINUX_MMU_NOTIFIER_H */