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

/* SPDX-License-Identifier: GPL-2.0 */
#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);

	/*
	 * 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. For more in depth
	 * discussion on this see Documentation/vm/mmu_notifier.txt
	 *
	 * 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_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,
				  bool only_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_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, false);
}

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

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 pudp_huge_clear_flush_notify(__vma, __haddr, __pud)		\
({									\
	unsigned long ___haddr = __haddr & HPAGE_PUD_MASK;		\
	struct mm_struct *___mm = (__vma)->vm_mm;			\
	pud_t ___pud;							\
									\
	___pud = pudp_huge_clear_flush(__vma, __haddr, __pud);		\
	mmu_notifier_invalidate_range(___mm, ___haddr,			\
				      ___haddr + HPAGE_PUD_SIZE);	\
									\
	___pud;								\
})

/*
 * 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 int mm_has_notifiers(struct mm_struct *mm)
{
	return 0;
}

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_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_only_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 pudp_huge_clear_flush_notify pudp_huge_clear_flush
#define set_pte_at_notify set_pte_at

#endif /* CONFIG_MMU_NOTIFIER */

#endif /* _LINUX_MMU_NOTIFIER_H */
Commit	Line	Data
b2441318	1	/* SPDX-License-Identifier: GPL-2.0 */
cddb8a5c AA	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>
21a92735	8	#include <linux/srcu.h>
cddb8a5c AA	9
	10	struct mmu_notifier;
	11	struct mmu_notifier_ops;
	12
	13	#ifdef CONFIG_MMU_NOTIFIER
	14
	15	/*
	16	* The mmu notifier_mm structure is allocated and installed in
	17	* mm->mmu_notifier_mm inside the mm_take_all_locks() protected
	18	* critical section and it's released only when mm_count reaches zero
	19	* in mmdrop().
	20	*/
	21	struct mmu_notifier_mm {
	22	/* all mmu notifiers registerd in this mm are queued in this list */
	23	struct hlist_head list;
	24	/* to serialize the list modifications and hlist_unhashed */
	25	spinlock_t lock;
	26	};
	27
	28	struct mmu_notifier_ops {
	29	/*
	30	* Called either by mmu_notifier_unregister or when the mm is
	31	* being destroyed by exit_mmap, always before all pages are
	32	* freed. This can run concurrently with other mmu notifier
	33	* methods (the ones invoked outside the mm context) and it
	34	* should tear down all secondary mmu mappings and freeze the
	35	* secondary mmu. If this method isn't implemented you've to
	36	* be sure that nothing could possibly write to the pages
	37	* through the secondary mmu by the time the last thread with
	38	* tsk->mm == mm exits.
	39	*
	40	* As side note: the pages freed after ->release returns could
	41	* be immediately reallocated by the gart at an alias physical
	42	* address with a different cache model, so if ->release isn't
	43	* implemented because all _software_ driven memory accesses
	44	* through the secondary mmu are terminated by the time the
	45	* last thread of this mm quits, you've also to be sure that
	46	* speculative _hardware_ operations can't allocate dirty
	47	* cachelines in the cpu that could not be snooped and made
	48	* coherent with the other read and write operations happening
	49	* through the gart alias address, so leading to memory
	50	* corruption.
	51	*/
	52	void (release)(struct mmu_notifier mn,
	53	struct mm_struct *mm);
	54
	55	/*
	56	* clear_flush_young is called after the VM is
	57	* test-and-clearing the young/accessed bitflag in the
	58	* pte. This way the VM will provide proper aging to the
	59	* accesses to the page through the secondary MMUs and not
	60	* only to the ones through the Linux pte.
57128468 ALC	61	* Start-end is necessary in case the secondary MMU is mapping the page
57128468 ALC	62	* at a smaller granularity than the primary MMU.
cddb8a5c AA	63	*/
	64	int (clear_flush_young)(struct mmu_notifier mn,
	65	struct mm_struct *mm,
57128468 ALC	66	unsigned long start,
57128468 ALC	67	unsigned long end);
cddb8a5c	68
1d7715c6 VD	69	/*
	70	* clear_young is a lightweight version of clear_flush_young. Like the
	71	* latter, it is supposed to test-and-clear the young/accessed bitflag
	72	* in the secondary pte, but it may omit flushing the secondary tlb.
	73	*/
	74	int (clear_young)(struct mmu_notifier mn,
	75	struct mm_struct *mm,
	76	unsigned long start,
	77	unsigned long end);
	78
8ee53820 AA	79	/*
	80	* test_young is called to check the young/accessed bitflag in
	81	* the secondary pte. This is used to know if the page is
	82	* frequently used without actually clearing the flag or tearing
	83	* down the secondary mapping on the page.
	84	*/
	85	int (test_young)(struct mmu_notifier mn,
	86	struct mm_struct *mm,
	87	unsigned long address);
	88
828502d3 IE	89	/*
	90	* change_pte is called in cases that pte mapping to page is changed:
	91	* for example, when ksm remaps pte to point to a new shared page.
	92	*/
	93	void (change_pte)(struct mmu_notifier mn,
	94	struct mm_struct *mm,
	95	unsigned long address,
	96	pte_t pte);
	97
cddb8a5c AA	98	/*
	99	* invalidate_range_start() and invalidate_range_end() must be
	100	* paired and are called only when the mmap_sem and/or the
0f0a327f JR	101	* locks protecting the reverse maps are held. If the subsystem
	102	* can't guarantee that no additional references are taken to
	103	* the pages in the range, it has to implement the
	104	* invalidate_range() notifier to remove any references taken
	105	* after invalidate_range_start().
cddb8a5c AA	106	*
	107	* Invalidation of multiple concurrent ranges may be
	108	* optionally permitted by the driver. Either way the
	109	* establishment of sptes is forbidden in the range passed to
	110	* invalidate_range_begin/end for the whole duration of the
	111	* invalidate_range_begin/end critical section.
	112	*
	113	* invalidate_range_start() is called when all pages in the
	114	* range are still mapped and have at least a refcount of one.
	115	*
	116	* invalidate_range_end() is called when all pages in the
	117	* range have been unmapped and the pages have been freed by
	118	* the VM.
	119	*
	120	* The VM will remove the page table entries and potentially
	121	* the page between invalidate_range_start() and
	122	* invalidate_range_end(). If the page must not be freed
	123	* because of pending I/O or other circumstances then the
	124	* invalidate_range_start() callback (or the initial mapping
	125	* by the driver) must make sure that the refcount is kept
	126	* elevated.
	127	*
	128	* If the driver increases the refcount when the pages are
	129	* initially mapped into an address space then either
	130	* invalidate_range_start() or invalidate_range_end() may
	131	* decrease the refcount. If the refcount is decreased on
	132	* invalidate_range_start() then the VM can free pages as page
	133	* table entries are removed. If the refcount is only
	134	* droppped on invalidate_range_end() then the driver itself
	135	* will drop the last refcount but it must take care to flush
	136	* any secondary tlb before doing the final free on the
	137	* page. Pages will no longer be referenced by the linux
	138	* address space but may still be referenced by sptes until
	139	* the last refcount is dropped.
	140	*/
	141	void (invalidate_range_start)(struct mmu_notifier mn,
	142	struct mm_struct *mm,
	143	unsigned long start, unsigned long end);
	144	void (invalidate_range_end)(struct mmu_notifier mn,
	145	struct mm_struct *mm,
	146	unsigned long start, unsigned long end);
0f0a327f JR	147
	148	/*
	149	* invalidate_range() is either called between
	150	* invalidate_range_start() and invalidate_range_end() when the
	151	* VM has to free pages that where unmapped, but before the
	152	* pages are actually freed, or outside of _start()/_end() when
	153	* a (remote) TLB is necessary.
	154	*
	155	* If invalidate_range() is used to manage a non-CPU TLB with
	156	* shared page-tables, it not necessary to implement the
	157	* invalidate_range_start()/end() notifiers, as
	158	* invalidate_range() alread catches the points in time when an
0f10851e JG	159	* external TLB range needs to be flushed. For more in depth
0f10851e JG	160	* discussion on this see Documentation/vm/mmu_notifier.txt
0f0a327f JR	161	*
	162	* The invalidate_range() function is called under the ptl
	163	* spin-lock and not allowed to sleep.
	164	*
	165	* Note that this function might be called with just a sub-range
	166	* of what was passed to invalidate_range_start()/end(), if
	167	* called between those functions.
	168	*/
	169	void (invalidate_range)(struct mmu_notifier mn, struct mm_struct *mm,
	170	unsigned long start, unsigned long end);
cddb8a5c AA	171	};
	172
	173	/*
	174	* The notifier chains are protected by mmap_sem and/or the reverse map
	175	* semaphores. Notifier chains are only changed when all reverse maps and
	176	* the mmap_sem locks are taken.
	177	*
	178	* Therefore notifier chains can only be traversed when either
	179	*
	180	* 1. mmap_sem is held.
c8c06efa	181	* 2. One of the reverse map locks is held (i_mmap_rwsem or anon_vma->rwsem).
cddb8a5c AA	182	* 3. No other concurrent thread can access the list (release)
	183	*/
	184	struct mmu_notifier {
	185	struct hlist_node hlist;
	186	const struct mmu_notifier_ops *ops;
	187	};
	188
	189	static inline int mm_has_notifiers(struct mm_struct *mm)
	190	{
	191	return unlikely(mm->mmu_notifier_mm);
	192	}
	193
	194	extern int mmu_notifier_register(struct mmu_notifier *mn,
	195	struct mm_struct *mm);
	196	extern int __mmu_notifier_register(struct mmu_notifier *mn,
	197	struct mm_struct *mm);
	198	extern void mmu_notifier_unregister(struct mmu_notifier *mn,
	199	struct mm_struct *mm);
b972216e PZ	200	extern void mmu_notifier_unregister_no_release(struct mmu_notifier *mn,
b972216e PZ	201	struct mm_struct *mm);
cddb8a5c AA	202	extern void __mmu_notifier_mm_destroy(struct mm_struct *mm);
	203	extern void __mmu_notifier_release(struct mm_struct *mm);
	204	extern int __mmu_notifier_clear_flush_young(struct mm_struct *mm,
57128468 ALC	205	unsigned long start,
57128468 ALC	206	unsigned long end);
1d7715c6 VD	207	extern int __mmu_notifier_clear_young(struct mm_struct *mm,
	208	unsigned long start,
	209	unsigned long end);
8ee53820 AA	210	extern int __mmu_notifier_test_young(struct mm_struct *mm,
8ee53820 AA	211	unsigned long address);
828502d3 IE	212	extern void __mmu_notifier_change_pte(struct mm_struct *mm,
828502d3 IE	213	unsigned long address, pte_t pte);
cddb8a5c AA	214	extern void __mmu_notifier_invalidate_range_start(struct mm_struct *mm,
	215	unsigned long start, unsigned long end);
	216	extern void __mmu_notifier_invalidate_range_end(struct mm_struct *mm,
4645b9fe JG	217	unsigned long start, unsigned long end,
4645b9fe JG	218	bool only_end);
0f0a327f JR	219	extern void __mmu_notifier_invalidate_range(struct mm_struct *mm,
0f0a327f JR	220	unsigned long start, unsigned long end);
cddb8a5c AA	221
	222	static inline void mmu_notifier_release(struct mm_struct *mm)
	223	{
	224	if (mm_has_notifiers(mm))
	225	__mmu_notifier_release(mm);
	226	}
	227
	228	static inline int mmu_notifier_clear_flush_young(struct mm_struct *mm,
57128468 ALC	229	unsigned long start,
57128468 ALC	230	unsigned long end)
cddb8a5c AA	231	{
cddb8a5c AA	232	if (mm_has_notifiers(mm))
57128468	233	return __mmu_notifier_clear_flush_young(mm, start, end);
cddb8a5c AA	234	return 0;
	235	}
	236
1d7715c6 VD	237	static inline int mmu_notifier_clear_young(struct mm_struct *mm,
	238	unsigned long start,
	239	unsigned long end)
	240	{
	241	if (mm_has_notifiers(mm))
	242	return __mmu_notifier_clear_young(mm, start, end);
	243	return 0;
	244	}
	245
8ee53820 AA	246	static inline int mmu_notifier_test_young(struct mm_struct *mm,
	247	unsigned long address)
	248	{
	249	if (mm_has_notifiers(mm))
	250	return __mmu_notifier_test_young(mm, address);
	251	return 0;
	252	}
	253
828502d3 IE	254	static inline void mmu_notifier_change_pte(struct mm_struct *mm,
	255	unsigned long address, pte_t pte)
	256	{
	257	if (mm_has_notifiers(mm))
	258	__mmu_notifier_change_pte(mm, address, pte);
	259	}
	260
cddb8a5c AA	261	static inline void mmu_notifier_invalidate_range_start(struct mm_struct *mm,
	262	unsigned long start, unsigned long end)
	263	{
	264	if (mm_has_notifiers(mm))
	265	__mmu_notifier_invalidate_range_start(mm, start, end);
	266	}
	267
	268	static inline void mmu_notifier_invalidate_range_end(struct mm_struct *mm,
	269	unsigned long start, unsigned long end)
	270	{
	271	if (mm_has_notifiers(mm))
4645b9fe JG	272	__mmu_notifier_invalidate_range_end(mm, start, end, false);
	273	}
	274
	275	static inline void mmu_notifier_invalidate_range_only_end(struct mm_struct *mm,
	276	unsigned long start, unsigned long end)
	277	{
	278	if (mm_has_notifiers(mm))
	279	__mmu_notifier_invalidate_range_end(mm, start, end, true);
cddb8a5c AA	280	}
cddb8a5c AA	281
1897bdc4 JR	282	static inline void mmu_notifier_invalidate_range(struct mm_struct *mm,
	283	unsigned long start, unsigned long end)
	284	{
0f0a327f JR	285	if (mm_has_notifiers(mm))
0f0a327f JR	286	__mmu_notifier_invalidate_range(mm, start, end);
1897bdc4 JR	287	}
1897bdc4 JR	288
cddb8a5c AA	289	static inline void mmu_notifier_mm_init(struct mm_struct *mm)
	290	{
	291	mm->mmu_notifier_mm = NULL;
	292	}
	293
	294	static inline void mmu_notifier_mm_destroy(struct mm_struct *mm)
	295	{
	296	if (mm_has_notifiers(mm))
	297	__mmu_notifier_mm_destroy(mm);
	298	}
	299
cddb8a5c AA	300	#define ptep_clear_flush_young_notify(__vma, __address, __ptep) \
	301	({ \
	302	int __young; \
	303	struct vm_area_struct *___vma = __vma; \
	304	unsigned long ___address = __address; \
	305	__young = ptep_clear_flush_young(___vma, ___address, __ptep); \
	306	__young \|= mmu_notifier_clear_flush_young(___vma->vm_mm, \
57128468 ALC	307	___address, \
	308	___address + \
	309	PAGE_SIZE); \
cddb8a5c AA	310	__young; \
	311	})
	312
91a4ee26 AA	313	#define pmdp_clear_flush_young_notify(__vma, __address, __pmdp) \
	314	({ \
	315	int __young; \
	316	struct vm_area_struct *___vma = __vma; \
	317	unsigned long ___address = __address; \
	318	__young = pmdp_clear_flush_young(___vma, ___address, __pmdp); \
	319	__young \|= mmu_notifier_clear_flush_young(___vma->vm_mm, \
57128468 ALC	320	___address, \
	321	___address + \
	322	PMD_SIZE); \
91a4ee26 AA	323	__young; \
	324	})
	325
1d7715c6 VD	326	#define ptep_clear_young_notify(__vma, __address, __ptep) \
	327	({ \
	328	int __young; \
	329	struct vm_area_struct *___vma = __vma; \
	330	unsigned long ___address = __address; \
	331	__young = ptep_test_and_clear_young(___vma, ___address, __ptep);\
	332	__young \|= mmu_notifier_clear_young(___vma->vm_mm, ___address, \
	333	___address + PAGE_SIZE); \
	334	__young; \
	335	})
	336
	337	#define pmdp_clear_young_notify(__vma, __address, __pmdp) \
	338	({ \
	339	int __young; \
	340	struct vm_area_struct *___vma = __vma; \
	341	unsigned long ___address = __address; \
	342	__young = pmdp_test_and_clear_young(___vma, ___address, __pmdp);\
	343	__young \|= mmu_notifier_clear_young(___vma->vm_mm, ___address, \
	344	___address + PMD_SIZE); \
	345	__young; \
	346	})
	347
34ee645e JR	348	#define ptep_clear_flush_notify(__vma, __address, __ptep) \
	349	({ \
	350	unsigned long ___addr = __address & PAGE_MASK; \
	351	struct mm_struct *___mm = (__vma)->vm_mm; \
	352	pte_t ___pte; \
	353	\
	354	___pte = ptep_clear_flush(__vma, __address, __ptep); \
	355	mmu_notifier_invalidate_range(___mm, ___addr, \
	356	___addr + PAGE_SIZE); \
	357	\
	358	___pte; \
	359	})
	360
8809aa2d	361	#define pmdp_huge_clear_flush_notify(__vma, __haddr, __pmd) \
34ee645e JR	362	({ \
	363	unsigned long ___haddr = __haddr & HPAGE_PMD_MASK; \
	364	struct mm_struct *___mm = (__vma)->vm_mm; \
	365	pmd_t ___pmd; \
	366	\
8809aa2d	367	___pmd = pmdp_huge_clear_flush(__vma, __haddr, __pmd); \
34ee645e JR	368	mmu_notifier_invalidate_range(___mm, ___haddr, \
	369	___haddr + HPAGE_PMD_SIZE); \
	370	\
	371	___pmd; \
	372	})
	373
a00cc7d9 MW	374	#define pudp_huge_clear_flush_notify(__vma, __haddr, __pud) \
	375	({ \
	376	unsigned long ___haddr = __haddr & HPAGE_PUD_MASK; \
	377	struct mm_struct *___mm = (__vma)->vm_mm; \
	378	pud_t ___pud; \
	379	\
	380	___pud = pudp_huge_clear_flush(__vma, __haddr, __pud); \
	381	mmu_notifier_invalidate_range(___mm, ___haddr, \
	382	___haddr + HPAGE_PUD_SIZE); \
	383	\
	384	___pud; \
	385	})
	386
48af0d7c XG	387	/*
	388	* set_pte_at_notify() sets the pte _after_ running the notifier.
	389	* This is safe to start by updating the secondary MMUs, because the primary MMU
	390	* pte invalidate must have already happened with a ptep_clear_flush() before
	391	* set_pte_at_notify() has been invoked. Updating the secondary MMUs first is
	392	* required when we change both the protection of the mapping from read-only to
	393	* read-write and the pfn (like during copy on write page faults). Otherwise the
	394	* old page would remain mapped readonly in the secondary MMUs after the new
	395	* page is already writable by some CPU through the primary MMU.
	396	*/
828502d3 IE	397	#define set_pte_at_notify(__mm, __address, __ptep, __pte) \
	398	({ \
	399	struct mm_struct *___mm = __mm; \
	400	unsigned long ___address = __address; \
	401	pte_t ___pte = __pte; \
	402	\
828502d3	403	mmu_notifier_change_pte(___mm, ___address, ___pte); \
48af0d7c	404	set_pte_at(___mm, ___address, __ptep, ___pte); \
828502d3 IE	405	})
828502d3 IE	406
b972216e PZ	407	extern void mmu_notifier_call_srcu(struct rcu_head *rcu,
	408	void (func)(struct rcu_head rcu));
	409	extern void mmu_notifier_synchronize(void);
	410
cddb8a5c AA	411	#else /* CONFIG_MMU_NOTIFIER */
cddb8a5c AA	412
4d4bbd85 MH	413	static inline int mm_has_notifiers(struct mm_struct *mm)
	414	{
	415	return 0;
	416	}
	417
cddb8a5c AA	418	static inline void mmu_notifier_release(struct mm_struct *mm)
	419	{
	420	}
	421
	422	static inline int mmu_notifier_clear_flush_young(struct mm_struct *mm,
57128468 ALC	423	unsigned long start,
57128468 ALC	424	unsigned long end)
8ee53820 AA	425	{
	426	return 0;
	427	}
	428
	429	static inline int mmu_notifier_test_young(struct mm_struct *mm,
	430	unsigned long address)
cddb8a5c AA	431	{
	432	return 0;
	433	}
	434
828502d3 IE	435	static inline void mmu_notifier_change_pte(struct mm_struct *mm,
	436	unsigned long address, pte_t pte)
	437	{
	438	}
	439
cddb8a5c AA	440	static inline void mmu_notifier_invalidate_range_start(struct mm_struct *mm,
	441	unsigned long start, unsigned long end)
	442	{
	443	}
	444
	445	static inline void mmu_notifier_invalidate_range_end(struct mm_struct *mm,
	446	unsigned long start, unsigned long end)
	447	{
	448	}
	449
4645b9fe JG	450	static inline void mmu_notifier_invalidate_range_only_end(struct mm_struct *mm,
	451	unsigned long start, unsigned long end)
	452	{
	453	}
	454
1897bdc4 JR	455	static inline void mmu_notifier_invalidate_range(struct mm_struct *mm,
	456	unsigned long start, unsigned long end)
	457	{
	458	}
	459
cddb8a5c AA	460	static inline void mmu_notifier_mm_init(struct mm_struct *mm)
	461	{
	462	}
	463
	464	static inline void mmu_notifier_mm_destroy(struct mm_struct *mm)
	465	{
	466	}
	467
	468	#define ptep_clear_flush_young_notify ptep_clear_flush_young
91a4ee26	469	#define pmdp_clear_flush_young_notify pmdp_clear_flush_young
33c3fc71 VD	470	#define ptep_clear_young_notify ptep_test_and_clear_young
33c3fc71 VD	471	#define pmdp_clear_young_notify pmdp_test_and_clear_young
34ee645e	472	#define ptep_clear_flush_notify ptep_clear_flush
8809aa2d	473	#define pmdp_huge_clear_flush_notify pmdp_huge_clear_flush
a00cc7d9	474	#define pudp_huge_clear_flush_notify pudp_huge_clear_flush
828502d3	475	#define set_pte_at_notify set_pte_at
cddb8a5c AA	476
	477	#endif /* CONFIG_MMU_NOTIFIER */
	478
	479	#endif /* _LINUX_MMU_NOTIFIER_H */