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72f87654c6
The event denotes that an area [start:end] moves to different location. Length change isn't reported as "new" addresses, if they appear on the uffd reader side they will not contain any data and the latter can just zeromap them. Waiting for the event ACK is also done outside of mmap sem, as for fork event. Link: http://lkml.kernel.org/r/20161216144821.5183-12-aarcange@redhat.com Signed-off-by: Pavel Emelyanov <xemul@parallels.com> Signed-off-by: Mike Rapoport <rppt@linux.vnet.ibm.com> Signed-off-by: Andrea Arcangeli <aarcange@redhat.com> Cc: "Dr. David Alan Gilbert" <dgilbert@redhat.com> Cc: Hillf Danton <hillf.zj@alibaba-inc.com> Cc: Michael Rapoport <RAPOPORT@il.ibm.com> Cc: Mike Kravetz <mike.kravetz@oracle.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
111 lines
2.8 KiB
C
111 lines
2.8 KiB
C
/*
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* include/linux/userfaultfd_k.h
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*
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* Copyright (C) 2015 Red Hat, Inc.
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*
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*/
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#ifndef _LINUX_USERFAULTFD_K_H
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#define _LINUX_USERFAULTFD_K_H
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#ifdef CONFIG_USERFAULTFD
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#include <linux/userfaultfd.h> /* linux/include/uapi/linux/userfaultfd.h */
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#include <linux/fcntl.h>
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/*
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* CAREFUL: Check include/uapi/asm-generic/fcntl.h when defining
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* new flags, since they might collide with O_* ones. We want
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* to re-use O_* flags that couldn't possibly have a meaning
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* from userfaultfd, in order to leave a free define-space for
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* shared O_* flags.
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*/
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#define UFFD_CLOEXEC O_CLOEXEC
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#define UFFD_NONBLOCK O_NONBLOCK
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#define UFFD_SHARED_FCNTL_FLAGS (O_CLOEXEC | O_NONBLOCK)
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#define UFFD_FLAGS_SET (EFD_SHARED_FCNTL_FLAGS)
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extern int handle_userfault(struct vm_fault *vmf, unsigned long reason);
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extern ssize_t mcopy_atomic(struct mm_struct *dst_mm, unsigned long dst_start,
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unsigned long src_start, unsigned long len);
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extern ssize_t mfill_zeropage(struct mm_struct *dst_mm,
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unsigned long dst_start,
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unsigned long len);
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/* mm helpers */
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static inline bool is_mergeable_vm_userfaultfd_ctx(struct vm_area_struct *vma,
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struct vm_userfaultfd_ctx vm_ctx)
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{
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return vma->vm_userfaultfd_ctx.ctx == vm_ctx.ctx;
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}
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static inline bool userfaultfd_missing(struct vm_area_struct *vma)
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{
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return vma->vm_flags & VM_UFFD_MISSING;
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}
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static inline bool userfaultfd_armed(struct vm_area_struct *vma)
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{
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return vma->vm_flags & (VM_UFFD_MISSING | VM_UFFD_WP);
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}
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extern int dup_userfaultfd(struct vm_area_struct *, struct list_head *);
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extern void dup_userfaultfd_complete(struct list_head *);
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extern void mremap_userfaultfd_prep(struct vm_area_struct *,
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struct vm_userfaultfd_ctx *);
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extern void mremap_userfaultfd_complete(struct vm_userfaultfd_ctx,
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unsigned long from, unsigned long to,
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unsigned long len);
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#else /* CONFIG_USERFAULTFD */
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/* mm helpers */
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static inline int handle_userfault(struct vm_fault *vmf, unsigned long reason)
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{
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return VM_FAULT_SIGBUS;
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}
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static inline bool is_mergeable_vm_userfaultfd_ctx(struct vm_area_struct *vma,
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struct vm_userfaultfd_ctx vm_ctx)
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{
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return true;
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}
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static inline bool userfaultfd_missing(struct vm_area_struct *vma)
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{
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return false;
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}
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static inline bool userfaultfd_armed(struct vm_area_struct *vma)
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{
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return false;
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}
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static inline int dup_userfaultfd(struct vm_area_struct *vma,
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struct list_head *l)
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{
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return 0;
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}
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static inline void dup_userfaultfd_complete(struct list_head *l)
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{
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}
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static inline void mremap_userfaultfd_prep(struct vm_area_struct *vma,
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struct vm_userfaultfd_ctx *ctx)
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{
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}
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static inline void mremap_userfaultfd_complete(struct vm_userfaultfd_ctx ctx,
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unsigned long from,
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unsigned long to,
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unsigned long len)
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{
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}
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#endif /* CONFIG_USERFAULTFD */
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#endif /* _LINUX_USERFAULTFD_K_H */
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