diff options
Diffstat (limited to 'include/linux/mmu_notifier.h')
| -rw-r--r-- | include/linux/mmu_notifier.h | 147 |
1 files changed, 118 insertions, 29 deletions
diff --git a/include/linux/mmu_notifier.h b/include/linux/mmu_notifier.h index 1bd8e6a09a3c..9e6caa8ecd19 100644 --- a/include/linux/mmu_notifier.h +++ b/include/linux/mmu_notifier.h @@ -6,9 +6,12 @@ #include <linux/spinlock.h> #include <linux/mm_types.h> #include <linux/srcu.h> +#include <linux/interval_tree.h> +struct mmu_notifier_mm; struct mmu_notifier; -struct mmu_notifier_ops; +struct mmu_notifier_range; +struct mmu_interval_notifier; /** * enum mmu_notifier_event - reason for the mmu notifier callback @@ -31,6 +34,9 @@ struct mmu_notifier_ops; * access flags). User should soft dirty the page in the end callback to make * sure that anyone relying on soft dirtyness catch pages that might be written * through non CPU mappings. + * + * @MMU_NOTIFY_RELEASE: used during mmu_interval_notifier invalidate to signal + * that the mm refcount is zero and the range is no longer accessible. */ enum mmu_notifier_event { MMU_NOTIFY_UNMAP = 0, @@ -38,38 +44,11 @@ enum mmu_notifier_event { MMU_NOTIFY_PROTECTION_VMA, MMU_NOTIFY_PROTECTION_PAGE, MMU_NOTIFY_SOFT_DIRTY, -}; - -#ifdef CONFIG_MMU_NOTIFIER - -#ifdef CONFIG_LOCKDEP -extern struct lockdep_map __mmu_notifier_invalidate_range_start_map; -#endif - -/* - * The mmu notifier_mm structure is allocated and installed in - * mm->mmu_notifier_mm inside the mm_take_all_locks() protected - * critical section and it's released only when mm_count reaches zero - * in mmdrop(). - */ -struct mmu_notifier_mm { - /* all mmu notifiers registerd in this mm are queued in this list */ - struct hlist_head list; - /* to serialize the list modifications and hlist_unhashed */ - spinlock_t lock; + MMU_NOTIFY_RELEASE, }; #define MMU_NOTIFIER_RANGE_BLOCKABLE (1 << 0) -struct mmu_notifier_range { - struct vm_area_struct *vma; - struct mm_struct *mm; - unsigned long start; - unsigned long end; - unsigned flags; - enum mmu_notifier_event event; -}; - struct mmu_notifier_ops { /* * Called either by mmu_notifier_unregister or when the mm is @@ -249,6 +228,41 @@ struct mmu_notifier { unsigned int users; }; +/** + * struct mmu_interval_notifier_ops + * @invalidate: Upon return the caller must stop using any SPTEs within this + * range. This function can sleep. Return false only if sleeping + * was required but mmu_notifier_range_blockable(range) is false. + */ +struct mmu_interval_notifier_ops { + bool (*invalidate)(struct mmu_interval_notifier *mni, + const struct mmu_notifier_range *range, + unsigned long cur_seq); +}; + +struct mmu_interval_notifier { + struct interval_tree_node interval_tree; + const struct mmu_interval_notifier_ops *ops; + struct mm_struct *mm; + struct hlist_node deferred_item; + unsigned long invalidate_seq; +}; + +#ifdef CONFIG_MMU_NOTIFIER + +#ifdef CONFIG_LOCKDEP +extern struct lockdep_map __mmu_notifier_invalidate_range_start_map; +#endif + +struct mmu_notifier_range { + struct vm_area_struct *vma; + struct mm_struct *mm; + unsigned long start; + unsigned long end; + unsigned flags; + enum mmu_notifier_event event; +}; + static inline int mm_has_notifiers(struct mm_struct *mm) { return unlikely(mm->mmu_notifier_mm); @@ -275,6 +289,81 @@ extern int __mmu_notifier_register(struct mmu_notifier *mn, struct mm_struct *mm); extern void mmu_notifier_unregister(struct mmu_notifier *mn, struct mm_struct *mm); + +unsigned long mmu_interval_read_begin(struct mmu_interval_notifier *mni); +int mmu_interval_notifier_insert(struct mmu_interval_notifier *mni, + struct mm_struct *mm, unsigned long start, + unsigned long length, + const struct mmu_interval_notifier_ops *ops); +int mmu_interval_notifier_insert_locked( + struct mmu_interval_notifier *mni, struct mm_struct *mm, + unsigned long start, unsigned long length, + const struct mmu_interval_notifier_ops *ops); +void mmu_interval_notifier_remove(struct mmu_interval_notifier *mni); + +/** + * mmu_interval_set_seq - Save the invalidation sequence + * @mni - The mni passed to invalidate + * @cur_seq - The cur_seq passed to the invalidate() callback + * + * This must be called unconditionally from the invalidate callback of a + * struct mmu_interval_notifier_ops under the same lock that is used to call + * mmu_interval_read_retry(). It updates the sequence number for later use by + * mmu_interval_read_retry(). The provided cur_seq will always be odd. + * + * If the caller does not call mmu_interval_read_begin() or + * mmu_interval_read_retry() then this call is not required. + */ +static inline void mmu_interval_set_seq(struct mmu_interval_notifier *mni, + unsigned long cur_seq) +{ + WRITE_ONCE(mni->invalidate_seq, cur_seq); +} + +/** + * mmu_interval_read_retry - End a read side critical section against a VA range + * mni: The range + * seq: The return of the paired mmu_interval_read_begin() + * + * This MUST be called under a user provided lock that is also held + * unconditionally by op->invalidate() when it calls mmu_interval_set_seq(). + * + * Each call should be paired with a single mmu_interval_read_begin() and + * should be used to conclude the read side. + * + * Returns true if an invalidation collided with this critical section, and + * the caller should retry. + */ +static inline bool mmu_interval_read_retry(struct mmu_interval_notifier *mni, + unsigned long seq) +{ + return mni->invalidate_seq != seq; +} + +/** + * mmu_interval_check_retry - Test if a collision has occurred + * mni: The range + * seq: The return of the matching mmu_interval_read_begin() + * + * This can be used in the critical section between mmu_interval_read_begin() + * and mmu_interval_read_retry(). A return of true indicates an invalidation + * has collided with this critical region and a future + * mmu_interval_read_retry() will return true. + * + * False is not reliable and only suggests a collision may not have + * occured. It can be called many times and does not have to hold the user + * provided lock. + * + * This call can be used as part of loops and other expensive operations to + * expedite a retry. + */ +static inline bool mmu_interval_check_retry(struct mmu_interval_notifier *mni, + unsigned long seq) +{ + /* Pairs with the WRITE_ONCE in mmu_interval_set_seq() */ + return READ_ONCE(mni->invalidate_seq) != seq; +} + extern void __mmu_notifier_mm_destroy(struct mm_struct *mm); extern void __mmu_notifier_release(struct mm_struct *mm); extern int __mmu_notifier_clear_flush_young(struct mm_struct *mm, |