480 lines
16 KiB
C
480 lines
16 KiB
C
/* 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 */
|