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linux_dsm_epyc7002/include/linux/mmu_notifier.h
Jason Gunthorpe 99cb252f5e mm/mmu_notifier: add an interval tree notifier 
Of the 13 users of mmu_notifiers, 8 of them use only
invalidate_range_start/end() and immediately intersect the
mmu_notifier_range with some kind of internal list of VAs.  4 use an
interval tree (i915_gem, radeon_mn, umem_odp, hfi1). 4 use a linked list
of some kind (scif_dma, vhost, gntdev, hmm)

And the remaining 5 either don't use invalidate_range_start() or do some
special thing with it.

It turns out that building a correct scheme with an interval tree is
pretty complicated, particularly if the use case is synchronizing against
another thread doing get_user_pages().  Many of these implementations have
various subtle and difficult to fix races.

This approach puts the interval tree as common code at the top of the mmu
notifier call tree and implements a shareable locking scheme.

It includes:
 - An interval tree tracking VA ranges, with per-range callbacks
 - A read/write locking scheme for the interval tree that avoids
   sleeping in the notifier path (for OOM killer)
 - A sequence counter based collision-retry locking scheme to tell
   device page fault that a VA range is being concurrently invalidated.

This is based on various ideas:
- hmm accumulates invalidated VA ranges and releases them when all
  invalidates are done, via active_invalidate_ranges count.
  This approach avoids having to intersect the interval tree twice (as
  umem_odp does) at the potential cost of a longer device page fault.

- kvm/umem_odp use a sequence counter to drive the collision retry,
  via invalidate_seq

- a deferred work todo list on unlock scheme like RTNL, via deferred_list.
  This makes adding/removing interval tree members more deterministic

- seqlock, except this version makes the seqlock idea multi-holder on the
  write side by protecting it with active_invalidate_ranges and a spinlock

To minimize MM overhead when only the interval tree is being used, the
entire SRCU and hlist overheads are dropped using some simple
branches. Similarly the interval tree overhead is dropped when in hlist
mode.

The overhead from the mandatory spinlock is broadly the same as most of
existing users which already had a lock (or two) of some sort on the
invalidation path.

Link: https://lore.kernel.org/r/20191112202231.3856-3-jgg@ziepe.ca
Acked-by: Christian König <christian.koenig@amd.com>
Tested-by: Philip Yang <Philip.Yang@amd.com>
Tested-by: Ralph Campbell <rcampbell@nvidia.com>
Reviewed-by: John Hubbard <jhubbard@nvidia.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>
2019-11-23 19:56:44 -04:00

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/* 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>
#include <linux/interval_tree.h>
struct mmu_notifier_mm;
struct mmu_notifier;
struct mmu_notifier_range;
struct mmu_interval_notifier;
/**
* enum mmu_notifier_event - reason for the mmu notifier callback
* @MMU_NOTIFY_UNMAP: either munmap() that unmap the range or a mremap() that
* move the range
*
* @MMU_NOTIFY_CLEAR: clear page table entry (many reasons for this like
* madvise() or replacing a page by another one, ...).
*
* @MMU_NOTIFY_PROTECTION_VMA: update is due to protection change for the range
* ie using the vma access permission (vm_page_prot) to update the whole range
* is enough no need to inspect changes to the CPU page table (mprotect()
* syscall)
*
* @MMU_NOTIFY_PROTECTION_PAGE: update is due to change in read/write flag for
* pages in the range so to mirror those changes the user must inspect the CPU
* page table (from the end callback).
*
* @MMU_NOTIFY_SOFT_DIRTY: soft dirty accounting (still same page and same
* 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,
MMU_NOTIFY_CLEAR,
MMU_NOTIFY_PROTECTION_VMA,
MMU_NOTIFY_PROTECTION_PAGE,
MMU_NOTIFY_SOFT_DIRTY,
MMU_NOTIFY_RELEASE,
};
#define MMU_NOTIFIER_RANGE_BLOCKABLE (1 << 0)
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.
*
* If blockable argument is set to false then the callback cannot
* sleep and has to return with -EAGAIN. 0 should be returned
* otherwise. Please note that if invalidate_range_start approves
* a non-blocking behavior then the same applies to
* invalidate_range_end.
*
*/
int (*invalidate_range_start)(struct mmu_notifier *mn,
const struct mmu_notifier_range *range);
void (*invalidate_range_end)(struct mmu_notifier *mn,
const struct mmu_notifier_range *range);
/*
* 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.rst
*
* 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);
/*
* These callbacks are used with the get/put interface to manage the
* lifetime of the mmu_notifier memory. alloc_notifier() returns a new
* notifier for use with the mm.
*
* free_notifier() is only called after the mmu_notifier has been
* fully put, calls to any ops callback are prevented and no ops
* callbacks are currently running. It is called from a SRCU callback
* and cannot sleep.
*/
struct mmu_notifier *(*alloc_notifier)(struct mm_struct *mm);
void (*free_notifier)(struct mmu_notifier *mn);
};
/*
* 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;
struct mm_struct *mm;
struct rcu_head rcu;
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);
}
struct mmu_notifier *mmu_notifier_get_locked(const struct mmu_notifier_ops *ops,
struct mm_struct *mm);
static inline struct mmu_notifier *
mmu_notifier_get(const struct mmu_notifier_ops *ops, struct mm_struct *mm)
{
struct mmu_notifier *ret;
down_write(&mm->mmap_sem);
ret = mmu_notifier_get_locked(ops, mm);
up_write(&mm->mmap_sem);
return ret;
}
void mmu_notifier_put(struct mmu_notifier *mn);
void mmu_notifier_synchronize(void);
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);
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,
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 int __mmu_notifier_invalidate_range_start(struct mmu_notifier_range *r);
extern void __mmu_notifier_invalidate_range_end(struct mmu_notifier_range *r,
bool only_end);
extern void __mmu_notifier_invalidate_range(struct mm_struct *mm,
unsigned long start, unsigned long end);
extern bool
mmu_notifier_range_update_to_read_only(const struct mmu_notifier_range *range);
static inline bool
mmu_notifier_range_blockable(const struct mmu_notifier_range *range)
{
return (range->flags & MMU_NOTIFIER_RANGE_BLOCKABLE);
}
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 mmu_notifier_range *range)
{
might_sleep();
lock_map_acquire(&__mmu_notifier_invalidate_range_start_map);
if (mm_has_notifiers(range->mm)) {
range->flags |= MMU_NOTIFIER_RANGE_BLOCKABLE;
__mmu_notifier_invalidate_range_start(range);
}
lock_map_release(&__mmu_notifier_invalidate_range_start_map);
}
static inline int
mmu_notifier_invalidate_range_start_nonblock(struct mmu_notifier_range *range)
{
int ret = 0;
lock_map_acquire(&__mmu_notifier_invalidate_range_start_map);
if (mm_has_notifiers(range->mm)) {
range->flags &= ~MMU_NOTIFIER_RANGE_BLOCKABLE;
ret = __mmu_notifier_invalidate_range_start(range);
}
lock_map_release(&__mmu_notifier_invalidate_range_start_map);
return ret;
}
static inline void
mmu_notifier_invalidate_range_end(struct mmu_notifier_range *range)
{
if (mmu_notifier_range_blockable(range))
might_sleep();
if (mm_has_notifiers(range->mm))
__mmu_notifier_invalidate_range_end(range, false);
}
static inline void
mmu_notifier_invalidate_range_only_end(struct mmu_notifier_range *range)
{
if (mm_has_notifiers(range->mm))
__mmu_notifier_invalidate_range_end(range, 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);
}
static inline void mmu_notifier_range_init(struct mmu_notifier_range *range,
enum mmu_notifier_event event,
unsigned flags,
struct vm_area_struct *vma,
struct mm_struct *mm,
unsigned long start,
unsigned long end)
{
range->vma = vma;
range->event = event;
range->mm = mm;
range->start = start;
range->end = end;
range->flags = flags;
}
#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); \
})
#else /* CONFIG_MMU_NOTIFIER */
struct mmu_notifier_range {
unsigned long start;
unsigned long end;
};
static inline void _mmu_notifier_range_init(struct mmu_notifier_range *range,
unsigned long start,
unsigned long end)
{
range->start = start;
range->end = end;
}
#define mmu_notifier_range_init(range,event,flags,vma,mm,start,end) \
_mmu_notifier_range_init(range, start, end)
static inline bool
mmu_notifier_range_blockable(const struct mmu_notifier_range *range)
{
return true;
}
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 mmu_notifier_range *range)
{
}
static inline int
mmu_notifier_invalidate_range_start_nonblock(struct mmu_notifier_range *range)
{
return 0;
}
static inline
void mmu_notifier_invalidate_range_end(struct mmu_notifier_range *range)
{
}
static inline void
mmu_notifier_invalidate_range_only_end(struct mmu_notifier_range *range)
{
}
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 mmu_notifier_range_update_to_read_only(r) false
#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
static inline void mmu_notifier_synchronize(void)
{
}
#endif /* CONFIG_MMU_NOTIFIER */
#endif /* _LINUX_MMU_NOTIFIER_H */
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