[mirror_ubuntu-bionic-kernel.git] / include / linux / mmu_notifier.h

#ifndef _LINUX_MMU_NOTIFIER_H
#define _LINUX_MMU_NOTIFIER_H

#include <linux/list.h>
#include <linux/spinlock.h>
#include <linux/mm_types.h>
#include <linux/srcu.h>

struct mmu_notifier;
struct mmu_notifier_ops;

#ifdef CONFIG_MMU_NOTIFIER

/*
 * 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;
};

struct mmu_notifier_ops {
	/*
	 * Called either by mmu_notifier_unregister or when the mm is
	 * being destroyed by exit_mmap, always before all pages are
	 * freed. This can run concurrently with other mmu notifier
	 * methods (the ones invoked outside the mm context) and it
	 * should tear down all secondary mmu mappings and freeze the
	 * secondary mmu. If this method isn't implemented you've to
	 * be sure that nothing could possibly write to the pages
	 * through the secondary mmu by the time the last thread with
	 * tsk->mm == mm exits.
	 *
	 * As side note: the pages freed after ->release returns could
	 * be immediately reallocated by the gart at an alias physical
	 * address with a different cache model, so if ->release isn't
	 * implemented because all _software_ driven memory accesses
	 * through the secondary mmu are terminated by the time the
	 * last thread of this mm quits, you've also to be sure that
	 * speculative _hardware_ operations can't allocate dirty
	 * cachelines in the cpu that could not be snooped and made
	 * coherent with the other read and write operations happening
	 * through the gart alias address, so leading to memory
	 * corruption.
	 */
	void (*release)(struct mmu_notifier *mn,
			struct mm_struct *mm);

	/*
	 * clear_flush_young is called after the VM is
	 * test-and-clearing the young/accessed bitflag in the
	 * pte. This way the VM will provide proper aging to the
	 * accesses to the page through the secondary MMUs and not
	 * only to the ones through the Linux pte.
	 * Start-end is necessary in case the secondary MMU is mapping the page
	 * at a smaller granularity than the primary MMU.
	 */
	int (*clear_flush_young)(struct mmu_notifier *mn,
				 struct mm_struct *mm,
				 unsigned long start,
				 unsigned long end);

	/*
	 * clear_young is a lightweight version of clear_flush_young. Like the
	 * latter, it is supposed to test-and-clear the young/accessed bitflag
	 * in the secondary pte, but it may omit flushing the secondary tlb.
	 */
	int (*clear_young)(struct mmu_notifier *mn,
			   struct mm_struct *mm,
			   unsigned long start,
			   unsigned long end);

	/*
	 * test_young is called to check the young/accessed bitflag in
	 * the secondary pte. This is used to know if the page is
	 * frequently used without actually clearing the flag or tearing
	 * down the secondary mapping on the page.
	 */
	int (*test_young)(struct mmu_notifier *mn,
			  struct mm_struct *mm,
			  unsigned long address);

	/*
	 * change_pte is called in cases that pte mapping to page is changed:
	 * for example, when ksm remaps pte to point to a new shared page.
	 */
	void (*change_pte)(struct mmu_notifier *mn,
			   struct mm_struct *mm,
			   unsigned long address,
			   pte_t pte);

	/*
	 * Before this is invoked any secondary MMU is still ok to
	 * read/write to the page previously pointed to by the Linux
	 * pte because the page hasn't been freed yet and it won't be
	 * freed until this returns. If required set_page_dirty has to
	 * be called internally to this method.
	 */
	void (*invalidate_page)(struct mmu_notifier *mn,
				struct mm_struct *mm,
				unsigned long address);

	/*
	 * invalidate_range_start() and invalidate_range_end() must be
	 * paired and are called only when the mmap_sem and/or the
	 * locks protecting the reverse maps are held. If the subsystem
	 * can't guarantee that no additional references are taken to
	 * the pages in the range, it has to implement the
	 * invalidate_range() notifier to remove any references taken
	 * after invalidate_range_start().
	 *
	 * Invalidation of multiple concurrent ranges may be
	 * optionally permitted by the driver. Either way the
	 * establishment of sptes is forbidden in the range passed to
	 * invalidate_range_begin/end for the whole duration of the
	 * invalidate_range_begin/end critical section.
	 *
	 * invalidate_range_start() is called when all pages in the
	 * range are still mapped and have at least a refcount of one.
	 *
	 * invalidate_range_end() is called when all pages in the
	 * range have been unmapped and the pages have been freed by
	 * the VM.
	 *
	 * The VM will remove the page table entries and potentially
	 * the page between invalidate_range_start() and
	 * invalidate_range_end(). If the page must not be freed
	 * because of pending I/O or other circumstances then the
	 * invalidate_range_start() callback (or the initial mapping
	 * by the driver) must make sure that the refcount is kept
	 * elevated.
	 *
	 * If the driver increases the refcount when the pages are
	 * initially mapped into an address space then either
	 * invalidate_range_start() or invalidate_range_end() may
	 * decrease the refcount. If the refcount is decreased on
	 * invalidate_range_start() then the VM can free pages as page
	 * table entries are removed.  If the refcount is only
	 * droppped on invalidate_range_end() then the driver itself
	 * will drop the last refcount but it must take care to flush
	 * any secondary tlb before doing the final free on the
	 * page. Pages will no longer be referenced by the linux
	 * address space but may still be referenced by sptes until
	 * the last refcount is dropped.
	 */
	void (*invalidate_range_start)(struct mmu_notifier *mn,
				       struct mm_struct *mm,
				       unsigned long start, unsigned long end);
	void (*invalidate_range_end)(struct mmu_notifier *mn,
				     struct mm_struct *mm,
				     unsigned long start, unsigned long end);

	/*
	 * invalidate_range() is either called between
	 * invalidate_range_start() and invalidate_range_end() when the
	 * VM has to free pages that where unmapped, but before the
	 * pages are actually freed, or outside of _start()/_end() when
	 * a (remote) TLB is necessary.
	 *
	 * If invalidate_range() is used to manage a non-CPU TLB with
	 * shared page-tables, it not necessary to implement the
	 * invalidate_range_start()/end() notifiers, as
	 * invalidate_range() alread catches the points in time when an
	 * external TLB range needs to be flushed.
	 *
	 * The invalidate_range() function is called under the ptl
	 * spin-lock and not allowed to sleep.
	 *
	 * Note that this function might be called with just a sub-range
	 * of what was passed to invalidate_range_start()/end(), if
	 * called between those functions.
	 */
	void (*invalidate_range)(struct mmu_notifier *mn, struct mm_struct *mm,
				 unsigned long start, unsigned long end);
};

/*
 * The notifier chains are protected by mmap_sem and/or the reverse map
 * semaphores. Notifier chains are only changed when all reverse maps and
 * the mmap_sem locks are taken.
 *
 * Therefore notifier chains can only be traversed when either
 *
 * 1. mmap_sem is held.
 * 2. One of the reverse map locks is held (i_mmap_rwsem or anon_vma->rwsem).
 * 3. No other concurrent thread can access the list (release)
 */
struct mmu_notifier {
	struct hlist_node hlist;
	const struct mmu_notifier_ops *ops;
};

static inline int mm_has_notifiers(struct mm_struct *mm)
{
	return unlikely(mm->mmu_notifier_mm);
}

extern int mmu_notifier_register(struct mmu_notifier *mn,
				 struct mm_struct *mm);
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);
extern void mmu_notifier_unregister_no_release(struct mmu_notifier *mn,
					       struct mm_struct *mm);
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,
					  unsigned long start,
					  unsigned long end);
extern int __mmu_notifier_clear_young(struct mm_struct *mm,
				      unsigned long start,
				      unsigned long end);
extern int __mmu_notifier_test_young(struct mm_struct *mm,
				     unsigned long address);
extern void __mmu_notifier_change_pte(struct mm_struct *mm,
				      unsigned long address, pte_t pte);
extern void __mmu_notifier_invalidate_page(struct mm_struct *mm,
					  unsigned long address);
extern void __mmu_notifier_invalidate_range_start(struct mm_struct *mm,
				  unsigned long start, unsigned long end);
extern void __mmu_notifier_invalidate_range_end(struct mm_struct *mm,
				  unsigned long start, unsigned long end);
extern void __mmu_notifier_invalidate_range(struct mm_struct *mm,
				  unsigned long start, unsigned long end);

static inline void mmu_notifier_release(struct mm_struct *mm)
{
	if (mm_has_notifiers(mm))
		__mmu_notifier_release(mm);
}

static inline int mmu_notifier_clear_flush_young(struct mm_struct *mm,
					  unsigned long start,
					  unsigned long end)
{
	if (mm_has_notifiers(mm))
		return __mmu_notifier_clear_flush_young(mm, start, end);
	return 0;
}

static inline int mmu_notifier_clear_young(struct mm_struct *mm,
					   unsigned long start,
					   unsigned long end)
{
	if (mm_has_notifiers(mm))
		return __mmu_notifier_clear_young(mm, start, end);
	return 0;
}

static inline int mmu_notifier_test_young(struct mm_struct *mm,
					  unsigned long address)
{
	if (mm_has_notifiers(mm))
		return __mmu_notifier_test_young(mm, address);
	return 0;
}

static inline void mmu_notifier_change_pte(struct mm_struct *mm,
					   unsigned long address, pte_t pte)
{
	if (mm_has_notifiers(mm))
		__mmu_notifier_change_pte(mm, address, pte);
}

static inline void mmu_notifier_invalidate_page(struct mm_struct *mm,
					  unsigned long address)
{
	if (mm_has_notifiers(mm))
		__mmu_notifier_invalidate_page(mm, address);
}

static inline void mmu_notifier_invalidate_range_start(struct mm_struct *mm,
				  unsigned long start, unsigned long end)
{
	if (mm_has_notifiers(mm))
		__mmu_notifier_invalidate_range_start(mm, start, end);
}

static inline void mmu_notifier_invalidate_range_end(struct mm_struct *mm,
				  unsigned long start, unsigned long end)
{
	if (mm_has_notifiers(mm))
		__mmu_notifier_invalidate_range_end(mm, start, end);
}

static inline void mmu_notifier_invalidate_range(struct mm_struct *mm,
				  unsigned long start, unsigned long end)
{
	if (mm_has_notifiers(mm))
		__mmu_notifier_invalidate_range(mm, start, end);
}

static inline void mmu_notifier_mm_init(struct mm_struct *mm)
{
	mm->mmu_notifier_mm = NULL;
}

static inline void mmu_notifier_mm_destroy(struct mm_struct *mm)
{
	if (mm_has_notifiers(mm))
		__mmu_notifier_mm_destroy(mm);
}

#define ptep_clear_flush_young_notify(__vma, __address, __ptep)		\
({									\
	int __young;							\
	struct vm_area_struct *___vma = __vma;				\
	unsigned long ___address = __address;				\
	__young = ptep_clear_flush_young(___vma, ___address, __ptep);	\
	__young |= mmu_notifier_clear_flush_young(___vma->vm_mm,	\
						  ___address,		\
						  ___address +		\
							PAGE_SIZE);	\
	__young;							\
})

#define pmdp_clear_flush_young_notify(__vma, __address, __pmdp)		\
({									\
	int __young;							\
	struct vm_area_struct *___vma = __vma;				\
	unsigned long ___address = __address;				\
	__young = pmdp_clear_flush_young(___vma, ___address, __pmdp);	\
	__young |= mmu_notifier_clear_flush_young(___vma->vm_mm,	\
						  ___address,		\
						  ___address +		\
							PMD_SIZE);	\
	__young;							\
})

#define ptep_clear_young_notify(__vma, __address, __ptep)		\
({									\
	int __young;							\
	struct vm_area_struct *___vma = __vma;				\
	unsigned long ___address = __address;				\
	__young = ptep_test_and_clear_young(___vma, ___address, __ptep);\
	__young |= mmu_notifier_clear_young(___vma->vm_mm, ___address,	\
					    ___address + PAGE_SIZE);	\
	__young;							\
})

#define pmdp_clear_young_notify(__vma, __address, __pmdp)		\
({									\
	int __young;							\
	struct vm_area_struct *___vma = __vma;				\
	unsigned long ___address = __address;				\
	__young = pmdp_test_and_clear_young(___vma, ___address, __pmdp);\
	__young |= mmu_notifier_clear_young(___vma->vm_mm, ___address,	\
					    ___address + PMD_SIZE);	\
	__young;							\
})

#define	ptep_clear_flush_notify(__vma, __address, __ptep)		\
({									\
	unsigned long ___addr = __address & PAGE_MASK;			\
	struct mm_struct *___mm = (__vma)->vm_mm;			\
	pte_t ___pte;							\
									\
	___pte = ptep_clear_flush(__vma, __address, __ptep);		\
	mmu_notifier_invalidate_range(___mm, ___addr,			\
					___addr + PAGE_SIZE);		\
									\
	___pte;								\
})

#define pmdp_huge_clear_flush_notify(__vma, __haddr, __pmd)		\
({									\
	unsigned long ___haddr = __haddr & HPAGE_PMD_MASK;		\
	struct mm_struct *___mm = (__vma)->vm_mm;			\
	pmd_t ___pmd;							\
									\
	___pmd = pmdp_huge_clear_flush(__vma, __haddr, __pmd);		\
	mmu_notifier_invalidate_range(___mm, ___haddr,			\
				      ___haddr + HPAGE_PMD_SIZE);	\
									\
	___pmd;								\
})

#define pmdp_huge_get_and_clear_notify(__mm, __haddr, __pmd)		\
({									\
	unsigned long ___haddr = __haddr & HPAGE_PMD_MASK;		\
	pmd_t ___pmd;							\
									\
	___pmd = pmdp_huge_get_and_clear(__mm, __haddr, __pmd);		\
	mmu_notifier_invalidate_range(__mm, ___haddr,			\
				      ___haddr + HPAGE_PMD_SIZE);	\
									\
	___pmd;								\
})

/*
 * set_pte_at_notify() sets the pte _after_ running the notifier.
 * This is safe to start by updating the secondary MMUs, because the primary MMU
 * pte invalidate must have already happened with a ptep_clear_flush() before
 * set_pte_at_notify() has been invoked.  Updating the secondary MMUs first is
 * required when we change both the protection of the mapping from read-only to
 * read-write and the pfn (like during copy on write page faults). Otherwise the
 * old page would remain mapped readonly in the secondary MMUs after the new
 * page is already writable by some CPU through the primary MMU.
 */
#define set_pte_at_notify(__mm, __address, __ptep, __pte)		\
({									\
	struct mm_struct *___mm = __mm;					\
	unsigned long ___address = __address;				\
	pte_t ___pte = __pte;						\
									\
	mmu_notifier_change_pte(___mm, ___address, ___pte);		\
	set_pte_at(___mm, ___address, __ptep, ___pte);			\
})

extern void mmu_notifier_call_srcu(struct rcu_head *rcu,
				   void (*func)(struct rcu_head *rcu));
extern void mmu_notifier_synchronize(void);

#else /* CONFIG_MMU_NOTIFIER */

static inline void mmu_notifier_release(struct mm_struct *mm)
{
}

static inline int mmu_notifier_clear_flush_young(struct mm_struct *mm,
					  unsigned long start,
					  unsigned long end)
{
	return 0;
}

static inline int mmu_notifier_test_young(struct mm_struct *mm,
					  unsigned long address)
{
	return 0;
}

static inline void mmu_notifier_change_pte(struct mm_struct *mm,
					   unsigned long address, pte_t pte)
{
}

static inline void mmu_notifier_invalidate_page(struct mm_struct *mm,
					  unsigned long address)
{
}

static inline void mmu_notifier_invalidate_range_start(struct mm_struct *mm,
				  unsigned long start, unsigned long end)
{
}

static inline void mmu_notifier_invalidate_range_end(struct mm_struct *mm,
				  unsigned long start, unsigned long end)
{
}

static inline void mmu_notifier_invalidate_range(struct mm_struct *mm,
				  unsigned long start, unsigned long end)
{
}

static inline void mmu_notifier_mm_init(struct mm_struct *mm)
{
}

static inline void mmu_notifier_mm_destroy(struct mm_struct *mm)
{
}

#define ptep_clear_flush_young_notify ptep_clear_flush_young
#define pmdp_clear_flush_young_notify pmdp_clear_flush_young
#define ptep_clear_young_notify ptep_test_and_clear_young
#define pmdp_clear_young_notify pmdp_test_and_clear_young
#define	ptep_clear_flush_notify ptep_clear_flush
#define pmdp_huge_clear_flush_notify pmdp_huge_clear_flush
#define pmdp_huge_get_and_clear_notify pmdp_huge_get_and_clear
#define set_pte_at_notify set_pte_at

#endif /* CONFIG_MMU_NOTIFIER */

#endif /* _LINUX_MMU_NOTIFIER_H */
Commit	Line	Data
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
57128468 ALC	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,
57128468 ALC	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	* Before this is invoked any secondary MMU is still ok to
	99	* read/write to the page previously pointed to by the Linux
	100	* pte because the page hasn't been freed yet and it won't be
	101	* freed until this returns. If required set_page_dirty has to
	102	* be called internally to this method.
	103	*/
	104	void (invalidate_page)(struct mmu_notifier mn,
	105	struct mm_struct *mm,
	106	unsigned long address);
	107
	108	/*
	109	* invalidate_range_start() and invalidate_range_end() must be
	110	* paired and are called only when the mmap_sem and/or the
0f0a327f JR	111	* locks protecting the reverse maps are held. If the subsystem
	112	* can't guarantee that no additional references are taken to
	113	* the pages in the range, it has to implement the
	114	* invalidate_range() notifier to remove any references taken
	115	* after invalidate_range_start().
cddb8a5c AA	116	*
	117	* Invalidation of multiple concurrent ranges may be
	118	* optionally permitted by the driver. Either way the
	119	* establishment of sptes is forbidden in the range passed to
	120	* invalidate_range_begin/end for the whole duration of the
	121	* invalidate_range_begin/end critical section.
	122	*
	123	* invalidate_range_start() is called when all pages in the
	124	* range are still mapped and have at least a refcount of one.
	125	*
	126	* invalidate_range_end() is called when all pages in the
	127	* range have been unmapped and the pages have been freed by
	128	* the VM.
	129	*
	130	* The VM will remove the page table entries and potentially
	131	* the page between invalidate_range_start() and
	132	* invalidate_range_end(). If the page must not be freed
	133	* because of pending I/O or other circumstances then the
	134	* invalidate_range_start() callback (or the initial mapping
	135	* by the driver) must make sure that the refcount is kept
	136	* elevated.
	137	*
	138	* If the driver increases the refcount when the pages are
	139	* initially mapped into an address space then either
	140	* invalidate_range_start() or invalidate_range_end() may
	141	* decrease the refcount. If the refcount is decreased on
	142	* invalidate_range_start() then the VM can free pages as page
	143	* table entries are removed. If the refcount is only
	144	* droppped on invalidate_range_end() then the driver itself
	145	* will drop the last refcount but it must take care to flush
	146	* any secondary tlb before doing the final free on the
	147	* page. Pages will no longer be referenced by the linux
	148	* address space but may still be referenced by sptes until
	149	* the last refcount is dropped.
	150	*/
	151	void (invalidate_range_start)(struct mmu_notifier mn,
	152	struct mm_struct *mm,
	153	unsigned long start, unsigned long end);
	154	void (invalidate_range_end)(struct mmu_notifier mn,
	155	struct mm_struct *mm,
	156	unsigned long start, unsigned long end);
0f0a327f JR	157
	158	/*
	159	* invalidate_range() is either called between
	160	* invalidate_range_start() and invalidate_range_end() when the
	161	* VM has to free pages that where unmapped, but before the
	162	* pages are actually freed, or outside of _start()/_end() when
	163	* a (remote) TLB is necessary.
	164	*
	165	* If invalidate_range() is used to manage a non-CPU TLB with
	166	* shared page-tables, it not necessary to implement the
	167	* invalidate_range_start()/end() notifiers, as
	168	* invalidate_range() alread catches the points in time when an
	169	* external TLB range needs to be flushed.
	170	*
	171	* The invalidate_range() function is called under the ptl
	172	* spin-lock and not allowed to sleep.
	173	*
	174	* Note that this function might be called with just a sub-range
	175	* of what was passed to invalidate_range_start()/end(), if
	176	* called between those functions.
	177	*/
	178	void (invalidate_range)(struct mmu_notifier mn, struct mm_struct *mm,
	179	unsigned long start, unsigned long end);
cddb8a5c AA	180	};
	181
	182	/*
	183	* The notifier chains are protected by mmap_sem and/or the reverse map
	184	* semaphores. Notifier chains are only changed when all reverse maps and
	185	* the mmap_sem locks are taken.
	186	*
	187	* Therefore notifier chains can only be traversed when either
	188	*
	189	* 1. mmap_sem is held.
c8c06efa	190	* 2. One of the reverse map locks is held (i_mmap_rwsem or anon_vma->rwsem).
cddb8a5c AA	191	* 3. No other concurrent thread can access the list (release)
	192	*/
	193	struct mmu_notifier {
	194	struct hlist_node hlist;
	195	const struct mmu_notifier_ops *ops;
	196	};
	197
	198	static inline int mm_has_notifiers(struct mm_struct *mm)
	199	{
	200	return unlikely(mm->mmu_notifier_mm);
	201	}
	202
	203	extern int mmu_notifier_register(struct mmu_notifier *mn,
	204	struct mm_struct *mm);
	205	extern int __mmu_notifier_register(struct mmu_notifier *mn,
	206	struct mm_struct *mm);
	207	extern void mmu_notifier_unregister(struct mmu_notifier *mn,
	208	struct mm_struct *mm);
b972216e PZ	209	extern void mmu_notifier_unregister_no_release(struct mmu_notifier *mn,
b972216e PZ	210	struct mm_struct *mm);
cddb8a5c AA	211	extern void __mmu_notifier_mm_destroy(struct mm_struct *mm);
	212	extern void __mmu_notifier_release(struct mm_struct *mm);
	213	extern int __mmu_notifier_clear_flush_young(struct mm_struct *mm,
57128468 ALC	214	unsigned long start,
57128468 ALC	215	unsigned long end);
1d7715c6 VD	216	extern int __mmu_notifier_clear_young(struct mm_struct *mm,
	217	unsigned long start,
	218	unsigned long end);
8ee53820 AA	219	extern int __mmu_notifier_test_young(struct mm_struct *mm,
8ee53820 AA	220	unsigned long address);
828502d3 IE	221	extern void __mmu_notifier_change_pte(struct mm_struct *mm,
828502d3 IE	222	unsigned long address, pte_t pte);
cddb8a5c AA	223	extern void __mmu_notifier_invalidate_page(struct mm_struct *mm,
	224	unsigned long address);
	225	extern void __mmu_notifier_invalidate_range_start(struct mm_struct *mm,
	226	unsigned long start, unsigned long end);
	227	extern void __mmu_notifier_invalidate_range_end(struct mm_struct *mm,
	228	unsigned long start, unsigned long end);
0f0a327f JR	229	extern void __mmu_notifier_invalidate_range(struct mm_struct *mm,
0f0a327f JR	230	unsigned long start, unsigned long end);
cddb8a5c AA	231
	232	static inline void mmu_notifier_release(struct mm_struct *mm)
	233	{
	234	if (mm_has_notifiers(mm))
	235	__mmu_notifier_release(mm);
	236	}
	237
	238	static inline int mmu_notifier_clear_flush_young(struct mm_struct *mm,
57128468 ALC	239	unsigned long start,
57128468 ALC	240	unsigned long end)
cddb8a5c AA	241	{
cddb8a5c AA	242	if (mm_has_notifiers(mm))
57128468	243	return __mmu_notifier_clear_flush_young(mm, start, end);
cddb8a5c AA	244	return 0;
	245	}
	246
1d7715c6 VD	247	static inline int mmu_notifier_clear_young(struct mm_struct *mm,
	248	unsigned long start,
	249	unsigned long end)
	250	{
	251	if (mm_has_notifiers(mm))
	252	return __mmu_notifier_clear_young(mm, start, end);
	253	return 0;
	254	}
	255
8ee53820 AA	256	static inline int mmu_notifier_test_young(struct mm_struct *mm,
	257	unsigned long address)
	258	{
	259	if (mm_has_notifiers(mm))
	260	return __mmu_notifier_test_young(mm, address);
	261	return 0;
	262	}
	263
828502d3 IE	264	static inline void mmu_notifier_change_pte(struct mm_struct *mm,
	265	unsigned long address, pte_t pte)
	266	{
	267	if (mm_has_notifiers(mm))
	268	__mmu_notifier_change_pte(mm, address, pte);
	269	}
	270
cddb8a5c AA	271	static inline void mmu_notifier_invalidate_page(struct mm_struct *mm,
	272	unsigned long address)
	273	{
	274	if (mm_has_notifiers(mm))
	275	__mmu_notifier_invalidate_page(mm, address);
	276	}
	277
	278	static inline void mmu_notifier_invalidate_range_start(struct mm_struct *mm,
	279	unsigned long start, unsigned long end)
	280	{
	281	if (mm_has_notifiers(mm))
	282	__mmu_notifier_invalidate_range_start(mm, start, end);
	283	}
	284
	285	static inline void mmu_notifier_invalidate_range_end(struct mm_struct *mm,
	286	unsigned long start, unsigned long end)
	287	{
	288	if (mm_has_notifiers(mm))
	289	__mmu_notifier_invalidate_range_end(mm, start, end);
	290	}
	291
1897bdc4 JR	292	static inline void mmu_notifier_invalidate_range(struct mm_struct *mm,
	293	unsigned long start, unsigned long end)
	294	{
0f0a327f JR	295	if (mm_has_notifiers(mm))
0f0a327f JR	296	__mmu_notifier_invalidate_range(mm, start, end);
1897bdc4 JR	297	}
1897bdc4 JR	298
cddb8a5c AA	299	static inline void mmu_notifier_mm_init(struct mm_struct *mm)
	300	{
	301	mm->mmu_notifier_mm = NULL;
	302	}
	303
	304	static inline void mmu_notifier_mm_destroy(struct mm_struct *mm)
	305	{
	306	if (mm_has_notifiers(mm))
	307	__mmu_notifier_mm_destroy(mm);
	308	}
	309
cddb8a5c AA	310	#define ptep_clear_flush_young_notify(__vma, __address, __ptep) \
	311	({ \
	312	int __young; \
	313	struct vm_area_struct *___vma = __vma; \
	314	unsigned long ___address = __address; \
	315	__young = ptep_clear_flush_young(___vma, ___address, __ptep); \
	316	__young \|= mmu_notifier_clear_flush_young(___vma->vm_mm, \
57128468 ALC	317	___address, \
	318	___address + \
	319	PAGE_SIZE); \
cddb8a5c AA	320	__young; \
	321	})
	322
91a4ee26 AA	323	#define pmdp_clear_flush_young_notify(__vma, __address, __pmdp) \
	324	({ \
	325	int __young; \
	326	struct vm_area_struct *___vma = __vma; \
	327	unsigned long ___address = __address; \
	328	__young = pmdp_clear_flush_young(___vma, ___address, __pmdp); \
	329	__young \|= mmu_notifier_clear_flush_young(___vma->vm_mm, \
57128468 ALC	330	___address, \
	331	___address + \
	332	PMD_SIZE); \
91a4ee26 AA	333	__young; \
	334	})
	335
1d7715c6 VD	336	#define ptep_clear_young_notify(__vma, __address, __ptep) \
	337	({ \
	338	int __young; \
	339	struct vm_area_struct *___vma = __vma; \
	340	unsigned long ___address = __address; \
	341	__young = ptep_test_and_clear_young(___vma, ___address, __ptep);\
	342	__young \|= mmu_notifier_clear_young(___vma->vm_mm, ___address, \
	343	___address + PAGE_SIZE); \
	344	__young; \
	345	})
	346
	347	#define pmdp_clear_young_notify(__vma, __address, __pmdp) \
	348	({ \
	349	int __young; \
	350	struct vm_area_struct *___vma = __vma; \
	351	unsigned long ___address = __address; \
	352	__young = pmdp_test_and_clear_young(___vma, ___address, __pmdp);\
	353	__young \|= mmu_notifier_clear_young(___vma->vm_mm, ___address, \
	354	___address + PMD_SIZE); \
	355	__young; \
	356	})
	357
34ee645e JR	358	#define ptep_clear_flush_notify(__vma, __address, __ptep) \
	359	({ \
	360	unsigned long ___addr = __address & PAGE_MASK; \
	361	struct mm_struct *___mm = (__vma)->vm_mm; \
	362	pte_t ___pte; \
	363	\
	364	___pte = ptep_clear_flush(__vma, __address, __ptep); \
	365	mmu_notifier_invalidate_range(___mm, ___addr, \
	366	___addr + PAGE_SIZE); \
	367	\
	368	___pte; \
	369	})
	370
8809aa2d	371	#define pmdp_huge_clear_flush_notify(__vma, __haddr, __pmd) \
34ee645e JR	372	({ \
	373	unsigned long ___haddr = __haddr & HPAGE_PMD_MASK; \
	374	struct mm_struct *___mm = (__vma)->vm_mm; \
	375	pmd_t ___pmd; \
	376	\
8809aa2d	377	___pmd = pmdp_huge_clear_flush(__vma, __haddr, __pmd); \
34ee645e JR	378	mmu_notifier_invalidate_range(___mm, ___haddr, \
	379	___haddr + HPAGE_PMD_SIZE); \
	380	\
	381	___pmd; \
	382	})
	383
8809aa2d	384	#define pmdp_huge_get_and_clear_notify(__mm, __haddr, __pmd) \
34ee645e JR	385	({ \
	386	unsigned long ___haddr = __haddr & HPAGE_PMD_MASK; \
	387	pmd_t ___pmd; \
	388	\
8809aa2d	389	___pmd = pmdp_huge_get_and_clear(__mm, __haddr, __pmd); \
34ee645e JR	390	mmu_notifier_invalidate_range(__mm, ___haddr, \
	391	___haddr + HPAGE_PMD_SIZE); \
	392	\
	393	___pmd; \
	394	})
	395
48af0d7c XG	396	/*
	397	* set_pte_at_notify() sets the pte _after_ running the notifier.
	398	* This is safe to start by updating the secondary MMUs, because the primary MMU
	399	* pte invalidate must have already happened with a ptep_clear_flush() before
	400	* set_pte_at_notify() has been invoked. Updating the secondary MMUs first is
	401	* required when we change both the protection of the mapping from read-only to
	402	* read-write and the pfn (like during copy on write page faults). Otherwise the
	403	* old page would remain mapped readonly in the secondary MMUs after the new
	404	* page is already writable by some CPU through the primary MMU.
	405	*/
828502d3 IE	406	#define set_pte_at_notify(__mm, __address, __ptep, __pte) \
	407	({ \
	408	struct mm_struct *___mm = __mm; \
	409	unsigned long ___address = __address; \
	410	pte_t ___pte = __pte; \
	411	\
828502d3	412	mmu_notifier_change_pte(___mm, ___address, ___pte); \
48af0d7c	413	set_pte_at(___mm, ___address, __ptep, ___pte); \
828502d3 IE	414	})
828502d3 IE	415
b972216e PZ	416	extern void mmu_notifier_call_srcu(struct rcu_head *rcu,
	417	void (func)(struct rcu_head rcu));
	418	extern void mmu_notifier_synchronize(void);
	419
cddb8a5c AA	420	#else /* CONFIG_MMU_NOTIFIER */
	421
	422	static inline void mmu_notifier_release(struct mm_struct *mm)
	423	{
	424	}
	425
	426	static inline int mmu_notifier_clear_flush_young(struct mm_struct *mm,
57128468 ALC	427	unsigned long start,
57128468 ALC	428	unsigned long end)
8ee53820 AA	429	{
	430	return 0;
	431	}
	432
	433	static inline int mmu_notifier_test_young(struct mm_struct *mm,
	434	unsigned long address)
cddb8a5c AA	435	{
	436	return 0;
	437	}
	438
828502d3 IE	439	static inline void mmu_notifier_change_pte(struct mm_struct *mm,
	440	unsigned long address, pte_t pte)
	441	{
	442	}
	443
cddb8a5c AA	444	static inline void mmu_notifier_invalidate_page(struct mm_struct *mm,
	445	unsigned long address)
	446	{
	447	}
	448
	449	static inline void mmu_notifier_invalidate_range_start(struct mm_struct *mm,
	450	unsigned long start, unsigned long end)
	451	{
	452	}
	453
	454	static inline void mmu_notifier_invalidate_range_end(struct mm_struct *mm,
	455	unsigned long start, unsigned long end)
	456	{
	457	}
	458
1897bdc4 JR	459	static inline void mmu_notifier_invalidate_range(struct mm_struct *mm,
	460	unsigned long start, unsigned long end)
	461	{
	462	}
	463
cddb8a5c AA	464	static inline void mmu_notifier_mm_init(struct mm_struct *mm)
	465	{
	466	}
	467
	468	static inline void mmu_notifier_mm_destroy(struct mm_struct *mm)
	469	{
	470	}
	471
	472	#define ptep_clear_flush_young_notify ptep_clear_flush_young
91a4ee26	473	#define pmdp_clear_flush_young_notify pmdp_clear_flush_young
33c3fc71 VD	474	#define ptep_clear_young_notify ptep_test_and_clear_young
33c3fc71 VD	475	#define pmdp_clear_young_notify pmdp_test_and_clear_young
34ee645e	476	#define ptep_clear_flush_notify ptep_clear_flush
8809aa2d AK	477	#define pmdp_huge_clear_flush_notify pmdp_huge_clear_flush
8809aa2d AK	478	#define pmdp_huge_get_and_clear_notify pmdp_huge_get_and_clear
828502d3	479	#define set_pte_at_notify set_pte_at
cddb8a5c AA	480
	481	#endif /* CONFIG_MMU_NOTIFIER */
	482
	483	#endif /* _LINUX_MMU_NOTIFIER_H */