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483 lines
16 KiB
483 lines
16 KiB
#ifndef _LINUX_MMU_NOTIFIER_H |
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#define _LINUX_MMU_NOTIFIER_H |
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#include <linux/list.h> |
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#include <linux/spinlock.h> |
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#include <linux/mm_types.h> |
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#include <linux/srcu.h> |
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struct mmu_notifier; |
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struct mmu_notifier_ops; |
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|
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#ifdef CONFIG_MMU_NOTIFIER |
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/* |
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* The mmu notifier_mm structure is allocated and installed in |
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* mm->mmu_notifier_mm inside the mm_take_all_locks() protected |
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* critical section and it's released only when mm_count reaches zero |
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* in mmdrop(). |
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*/ |
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struct mmu_notifier_mm { |
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/* all mmu notifiers registerd in this mm are queued in this list */ |
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struct hlist_head list; |
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/* to serialize the list modifications and hlist_unhashed */ |
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spinlock_t lock; |
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}; |
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struct mmu_notifier_ops { |
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/* |
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* Called either by mmu_notifier_unregister or when the mm is |
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* being destroyed by exit_mmap, always before all pages are |
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* freed. This can run concurrently with other mmu notifier |
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* methods (the ones invoked outside the mm context) and it |
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* should tear down all secondary mmu mappings and freeze the |
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* secondary mmu. If this method isn't implemented you've to |
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* be sure that nothing could possibly write to the pages |
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* through the secondary mmu by the time the last thread with |
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* tsk->mm == mm exits. |
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* |
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* As side note: the pages freed after ->release returns could |
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* be immediately reallocated by the gart at an alias physical |
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* address with a different cache model, so if ->release isn't |
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* implemented because all _software_ driven memory accesses |
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* through the secondary mmu are terminated by the time the |
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* last thread of this mm quits, you've also to be sure that |
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* speculative _hardware_ operations can't allocate dirty |
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* cachelines in the cpu that could not be snooped and made |
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* coherent with the other read and write operations happening |
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* through the gart alias address, so leading to memory |
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* corruption. |
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*/ |
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void (*release)(struct mmu_notifier *mn, |
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struct mm_struct *mm); |
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/* |
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* clear_flush_young is called after the VM is |
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* test-and-clearing the young/accessed bitflag in the |
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* pte. This way the VM will provide proper aging to the |
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* accesses to the page through the secondary MMUs and not |
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* only to the ones through the Linux pte. |
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* Start-end is necessary in case the secondary MMU is mapping the page |
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* at a smaller granularity than the primary MMU. |
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*/ |
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int (*clear_flush_young)(struct mmu_notifier *mn, |
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struct mm_struct *mm, |
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unsigned long start, |
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unsigned long end); |
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/* |
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* clear_young is a lightweight version of clear_flush_young. Like the |
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* latter, it is supposed to test-and-clear the young/accessed bitflag |
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* in the secondary pte, but it may omit flushing the secondary tlb. |
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*/ |
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int (*clear_young)(struct mmu_notifier *mn, |
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struct mm_struct *mm, |
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unsigned long start, |
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unsigned long end); |
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/* |
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* test_young is called to check the young/accessed bitflag in |
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* the secondary pte. This is used to know if the page is |
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* frequently used without actually clearing the flag or tearing |
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* down the secondary mapping on the page. |
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*/ |
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int (*test_young)(struct mmu_notifier *mn, |
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struct mm_struct *mm, |
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unsigned long address); |
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/* |
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* change_pte is called in cases that pte mapping to page is changed: |
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* for example, when ksm remaps pte to point to a new shared page. |
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*/ |
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void (*change_pte)(struct mmu_notifier *mn, |
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struct mm_struct *mm, |
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unsigned long address, |
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pte_t pte); |
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/* |
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* Before this is invoked any secondary MMU is still ok to |
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* read/write to the page previously pointed to by the Linux |
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* pte because the page hasn't been freed yet and it won't be |
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* freed until this returns. If required set_page_dirty has to |
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* be called internally to this method. |
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*/ |
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void (*invalidate_page)(struct mmu_notifier *mn, |
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struct mm_struct *mm, |
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unsigned long address); |
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/* |
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* invalidate_range_start() and invalidate_range_end() must be |
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* paired and are called only when the mmap_sem and/or the |
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* locks protecting the reverse maps are held. If the subsystem |
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* can't guarantee that no additional references are taken to |
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* the pages in the range, it has to implement the |
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* invalidate_range() notifier to remove any references taken |
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* after invalidate_range_start(). |
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* |
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* Invalidation of multiple concurrent ranges may be |
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* optionally permitted by the driver. Either way the |
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* establishment of sptes is forbidden in the range passed to |
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* invalidate_range_begin/end for the whole duration of the |
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* invalidate_range_begin/end critical section. |
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* |
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* invalidate_range_start() is called when all pages in the |
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* range are still mapped and have at least a refcount of one. |
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* |
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* invalidate_range_end() is called when all pages in the |
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* range have been unmapped and the pages have been freed by |
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* the VM. |
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* |
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* The VM will remove the page table entries and potentially |
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* the page between invalidate_range_start() and |
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* invalidate_range_end(). If the page must not be freed |
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* because of pending I/O or other circumstances then the |
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* invalidate_range_start() callback (or the initial mapping |
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* by the driver) must make sure that the refcount is kept |
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* elevated. |
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* |
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* If the driver increases the refcount when the pages are |
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* initially mapped into an address space then either |
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* invalidate_range_start() or invalidate_range_end() may |
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* decrease the refcount. If the refcount is decreased on |
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* invalidate_range_start() then the VM can free pages as page |
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* table entries are removed. If the refcount is only |
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* droppped on invalidate_range_end() then the driver itself |
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* will drop the last refcount but it must take care to flush |
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* any secondary tlb before doing the final free on the |
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* page. Pages will no longer be referenced by the linux |
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* address space but may still be referenced by sptes until |
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* the last refcount is dropped. |
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*/ |
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void (*invalidate_range_start)(struct mmu_notifier *mn, |
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struct mm_struct *mm, |
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unsigned long start, unsigned long end); |
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void (*invalidate_range_end)(struct mmu_notifier *mn, |
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struct mm_struct *mm, |
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unsigned long start, unsigned long end); |
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/* |
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* invalidate_range() is either called between |
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* invalidate_range_start() and invalidate_range_end() when the |
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* VM has to free pages that where unmapped, but before the |
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* pages are actually freed, or outside of _start()/_end() when |
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* a (remote) TLB is necessary. |
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* |
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* If invalidate_range() is used to manage a non-CPU TLB with |
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* shared page-tables, it not necessary to implement the |
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* invalidate_range_start()/end() notifiers, as |
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* invalidate_range() alread catches the points in time when an |
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* external TLB range needs to be flushed. |
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* |
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* The invalidate_range() function is called under the ptl |
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* spin-lock and not allowed to sleep. |
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* |
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* Note that this function might be called with just a sub-range |
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* of what was passed to invalidate_range_start()/end(), if |
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* called between those functions. |
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*/ |
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void (*invalidate_range)(struct mmu_notifier *mn, struct mm_struct *mm, |
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unsigned long start, unsigned long end); |
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}; |
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/* |
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* The notifier chains are protected by mmap_sem and/or the reverse map |
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* semaphores. Notifier chains are only changed when all reverse maps and |
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* the mmap_sem locks are taken. |
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* |
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* Therefore notifier chains can only be traversed when either |
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* |
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* 1. mmap_sem is held. |
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* 2. One of the reverse map locks is held (i_mmap_rwsem or anon_vma->rwsem). |
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* 3. No other concurrent thread can access the list (release) |
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*/ |
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struct mmu_notifier { |
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struct hlist_node hlist; |
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const struct mmu_notifier_ops *ops; |
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}; |
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static inline int mm_has_notifiers(struct mm_struct *mm) |
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{ |
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return unlikely(mm->mmu_notifier_mm); |
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} |
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extern int mmu_notifier_register(struct mmu_notifier *mn, |
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struct mm_struct *mm); |
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extern int __mmu_notifier_register(struct mmu_notifier *mn, |
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struct mm_struct *mm); |
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extern void mmu_notifier_unregister(struct mmu_notifier *mn, |
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struct mm_struct *mm); |
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extern void mmu_notifier_unregister_no_release(struct mmu_notifier *mn, |
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struct mm_struct *mm); |
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extern void __mmu_notifier_mm_destroy(struct mm_struct *mm); |
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extern void __mmu_notifier_release(struct mm_struct *mm); |
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extern int __mmu_notifier_clear_flush_young(struct mm_struct *mm, |
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unsigned long start, |
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unsigned long end); |
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extern int __mmu_notifier_clear_young(struct mm_struct *mm, |
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unsigned long start, |
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unsigned long end); |
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extern int __mmu_notifier_test_young(struct mm_struct *mm, |
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unsigned long address); |
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extern void __mmu_notifier_change_pte(struct mm_struct *mm, |
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unsigned long address, pte_t pte); |
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extern void __mmu_notifier_invalidate_page(struct mm_struct *mm, |
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unsigned long address); |
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extern void __mmu_notifier_invalidate_range_start(struct mm_struct *mm, |
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unsigned long start, unsigned long end); |
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extern void __mmu_notifier_invalidate_range_end(struct mm_struct *mm, |
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unsigned long start, unsigned long end); |
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extern void __mmu_notifier_invalidate_range(struct mm_struct *mm, |
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unsigned long start, unsigned long end); |
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static inline void mmu_notifier_release(struct mm_struct *mm) |
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{ |
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if (mm_has_notifiers(mm)) |
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__mmu_notifier_release(mm); |
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} |
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static inline int mmu_notifier_clear_flush_young(struct mm_struct *mm, |
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unsigned long start, |
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unsigned long end) |
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{ |
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if (mm_has_notifiers(mm)) |
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return __mmu_notifier_clear_flush_young(mm, start, end); |
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return 0; |
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} |
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static inline int mmu_notifier_clear_young(struct mm_struct *mm, |
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unsigned long start, |
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unsigned long end) |
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{ |
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if (mm_has_notifiers(mm)) |
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return __mmu_notifier_clear_young(mm, start, end); |
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return 0; |
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} |
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static inline int mmu_notifier_test_young(struct mm_struct *mm, |
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unsigned long address) |
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{ |
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if (mm_has_notifiers(mm)) |
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return __mmu_notifier_test_young(mm, address); |
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return 0; |
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} |
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static inline void mmu_notifier_change_pte(struct mm_struct *mm, |
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unsigned long address, pte_t pte) |
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{ |
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if (mm_has_notifiers(mm)) |
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__mmu_notifier_change_pte(mm, address, pte); |
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} |
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static inline void mmu_notifier_invalidate_page(struct mm_struct *mm, |
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unsigned long address) |
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{ |
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if (mm_has_notifiers(mm)) |
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__mmu_notifier_invalidate_page(mm, address); |
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} |
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static inline void mmu_notifier_invalidate_range_start(struct mm_struct *mm, |
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unsigned long start, unsigned long end) |
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{ |
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if (mm_has_notifiers(mm)) |
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__mmu_notifier_invalidate_range_start(mm, start, end); |
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} |
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static inline void mmu_notifier_invalidate_range_end(struct mm_struct *mm, |
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unsigned long start, unsigned long end) |
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{ |
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if (mm_has_notifiers(mm)) |
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__mmu_notifier_invalidate_range_end(mm, start, end); |
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} |
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static inline void mmu_notifier_invalidate_range(struct mm_struct *mm, |
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unsigned long start, unsigned long end) |
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{ |
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if (mm_has_notifiers(mm)) |
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__mmu_notifier_invalidate_range(mm, start, end); |
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} |
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static inline void mmu_notifier_mm_init(struct mm_struct *mm) |
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{ |
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mm->mmu_notifier_mm = NULL; |
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} |
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static inline void mmu_notifier_mm_destroy(struct mm_struct *mm) |
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{ |
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if (mm_has_notifiers(mm)) |
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__mmu_notifier_mm_destroy(mm); |
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} |
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#define ptep_clear_flush_young_notify(__vma, __address, __ptep) \ |
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({ \ |
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int __young; \ |
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struct vm_area_struct *___vma = __vma; \ |
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unsigned long ___address = __address; \ |
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__young = ptep_clear_flush_young(___vma, ___address, __ptep); \ |
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__young |= mmu_notifier_clear_flush_young(___vma->vm_mm, \ |
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___address, \ |
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___address + \ |
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PAGE_SIZE); \ |
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__young; \ |
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}) |
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#define pmdp_clear_flush_young_notify(__vma, __address, __pmdp) \ |
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({ \ |
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int __young; \ |
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struct vm_area_struct *___vma = __vma; \ |
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unsigned long ___address = __address; \ |
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__young = pmdp_clear_flush_young(___vma, ___address, __pmdp); \ |
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__young |= mmu_notifier_clear_flush_young(___vma->vm_mm, \ |
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___address, \ |
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___address + \ |
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PMD_SIZE); \ |
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__young; \ |
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}) |
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#define ptep_clear_young_notify(__vma, __address, __ptep) \ |
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({ \ |
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int __young; \ |
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struct vm_area_struct *___vma = __vma; \ |
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unsigned long ___address = __address; \ |
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__young = ptep_test_and_clear_young(___vma, ___address, __ptep);\ |
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__young |= mmu_notifier_clear_young(___vma->vm_mm, ___address, \ |
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___address + PAGE_SIZE); \ |
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__young; \ |
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}) |
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#define pmdp_clear_young_notify(__vma, __address, __pmdp) \ |
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({ \ |
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int __young; \ |
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struct vm_area_struct *___vma = __vma; \ |
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unsigned long ___address = __address; \ |
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__young = pmdp_test_and_clear_young(___vma, ___address, __pmdp);\ |
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__young |= mmu_notifier_clear_young(___vma->vm_mm, ___address, \ |
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___address + PMD_SIZE); \ |
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__young; \ |
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}) |
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#define ptep_clear_flush_notify(__vma, __address, __ptep) \ |
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({ \ |
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unsigned long ___addr = __address & PAGE_MASK; \ |
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struct mm_struct *___mm = (__vma)->vm_mm; \ |
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pte_t ___pte; \ |
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\ |
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___pte = ptep_clear_flush(__vma, __address, __ptep); \ |
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mmu_notifier_invalidate_range(___mm, ___addr, \ |
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___addr + PAGE_SIZE); \ |
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\ |
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___pte; \ |
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}) |
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#define pmdp_huge_clear_flush_notify(__vma, __haddr, __pmd) \ |
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({ \ |
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unsigned long ___haddr = __haddr & HPAGE_PMD_MASK; \ |
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struct mm_struct *___mm = (__vma)->vm_mm; \ |
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pmd_t ___pmd; \ |
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\ |
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___pmd = pmdp_huge_clear_flush(__vma, __haddr, __pmd); \ |
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mmu_notifier_invalidate_range(___mm, ___haddr, \ |
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___haddr + HPAGE_PMD_SIZE); \ |
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\ |
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___pmd; \ |
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}) |
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#define pmdp_huge_get_and_clear_notify(__mm, __haddr, __pmd) \ |
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({ \ |
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unsigned long ___haddr = __haddr & HPAGE_PMD_MASK; \ |
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pmd_t ___pmd; \ |
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\ |
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___pmd = pmdp_huge_get_and_clear(__mm, __haddr, __pmd); \ |
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mmu_notifier_invalidate_range(__mm, ___haddr, \ |
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___haddr + HPAGE_PMD_SIZE); \ |
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\ |
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___pmd; \ |
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}) |
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/* |
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* set_pte_at_notify() sets the pte _after_ running the notifier. |
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* This is safe to start by updating the secondary MMUs, because the primary MMU |
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* pte invalidate must have already happened with a ptep_clear_flush() before |
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* set_pte_at_notify() has been invoked. Updating the secondary MMUs first is |
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* required when we change both the protection of the mapping from read-only to |
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* read-write and the pfn (like during copy on write page faults). Otherwise the |
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* old page would remain mapped readonly in the secondary MMUs after the new |
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* page is already writable by some CPU through the primary MMU. |
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*/ |
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#define set_pte_at_notify(__mm, __address, __ptep, __pte) \ |
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({ \ |
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struct mm_struct *___mm = __mm; \ |
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unsigned long ___address = __address; \ |
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pte_t ___pte = __pte; \ |
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\ |
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mmu_notifier_change_pte(___mm, ___address, ___pte); \ |
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set_pte_at(___mm, ___address, __ptep, ___pte); \ |
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}) |
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extern void mmu_notifier_call_srcu(struct rcu_head *rcu, |
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void (*func)(struct rcu_head *rcu)); |
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extern void mmu_notifier_synchronize(void); |
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#else /* CONFIG_MMU_NOTIFIER */ |
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static inline void mmu_notifier_release(struct mm_struct *mm) |
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{ |
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} |
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static inline int mmu_notifier_clear_flush_young(struct mm_struct *mm, |
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unsigned long start, |
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unsigned long end) |
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{ |
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return 0; |
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} |
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static inline int mmu_notifier_test_young(struct mm_struct *mm, |
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unsigned long address) |
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{ |
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return 0; |
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} |
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static inline void mmu_notifier_change_pte(struct mm_struct *mm, |
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unsigned long address, pte_t pte) |
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{ |
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} |
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static inline void mmu_notifier_invalidate_page(struct mm_struct *mm, |
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unsigned long address) |
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{ |
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} |
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static inline void mmu_notifier_invalidate_range_start(struct mm_struct *mm, |
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unsigned long start, unsigned long end) |
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{ |
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} |
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static inline void mmu_notifier_invalidate_range_end(struct mm_struct *mm, |
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unsigned long start, unsigned long end) |
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{ |
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} |
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static inline void mmu_notifier_invalidate_range(struct mm_struct *mm, |
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unsigned long start, unsigned long end) |
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{ |
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} |
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static inline void mmu_notifier_mm_init(struct mm_struct *mm) |
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{ |
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} |
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static inline void mmu_notifier_mm_destroy(struct mm_struct *mm) |
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{ |
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} |
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#define ptep_clear_flush_young_notify ptep_clear_flush_young |
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#define pmdp_clear_flush_young_notify pmdp_clear_flush_young |
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#define ptep_clear_young_notify ptep_test_and_clear_young |
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#define pmdp_clear_young_notify pmdp_test_and_clear_young |
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#define ptep_clear_flush_notify ptep_clear_flush |
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#define pmdp_huge_clear_flush_notify pmdp_huge_clear_flush |
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#define pmdp_huge_get_and_clear_notify pmdp_huge_get_and_clear |
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#define set_pte_at_notify set_pte_at |
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#endif /* CONFIG_MMU_NOTIFIER */ |
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#endif /* _LINUX_MMU_NOTIFIER_H */
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