userfaultfd_k.h
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/*
* include/linux/userfaultfd_k.h
*
* Copyright (C) 2015 Red Hat, Inc.
*
*/
#ifndef _LINUX_USERFAULTFD_K_H
#define _LINUX_USERFAULTFD_K_H
#ifdef CONFIG_USERFAULTFD
#include <linux/userfaultfd.h> /* linux/include/uapi/linux/userfaultfd.h */
#include <linux/fcntl.h>
/*
* CAREFUL: Check include/uapi/asm-generic/fcntl.h when defining
* new flags, since they might collide with O_* ones. We want
* to re-use O_* flags that couldn't possibly have a meaning
* from userfaultfd, in order to leave a free define-space for
* shared O_* flags.
*/
#define UFFD_CLOEXEC O_CLOEXEC
#define UFFD_NONBLOCK O_NONBLOCK
#define UFFD_SHARED_FCNTL_FLAGS (O_CLOEXEC | O_NONBLOCK)
#define UFFD_FLAGS_SET (EFD_SHARED_FCNTL_FLAGS)
extern int handle_userfault(struct vm_area_struct *vma, unsigned long address,
unsigned int flags, unsigned long reason);
extern ssize_t mcopy_atomic(struct mm_struct *dst_mm, unsigned long dst_start,
unsigned long src_start, unsigned long len);
extern ssize_t mfill_zeropage(struct mm_struct *dst_mm,
unsigned long dst_start,
unsigned long len);
/* mm helpers */
static inline bool is_mergeable_vm_userfaultfd_ctx(struct vm_area_struct *vma,
struct vm_userfaultfd_ctx vm_ctx)
{
return vma->vm_userfaultfd_ctx.ctx == vm_ctx.ctx;
}
static inline bool userfaultfd_missing(struct vm_area_struct *vma)
{
return vma->vm_flags & VM_UFFD_MISSING;
}
static inline bool userfaultfd_armed(struct vm_area_struct *vma)
{
return vma->vm_flags & (VM_UFFD_MISSING | VM_UFFD_WP);
}
#else /* CONFIG_USERFAULTFD */
/* mm helpers */
static inline int handle_userfault(struct vm_area_struct *vma,
unsigned long address,
unsigned int flags,
unsigned long reason)
{
return VM_FAULT_SIGBUS;
}
static inline bool is_mergeable_vm_userfaultfd_ctx(struct vm_area_struct *vma,
struct vm_userfaultfd_ctx vm_ctx)
{
return true;
}
static inline bool userfaultfd_missing(struct vm_area_struct *vma)
{
return false;
}
static inline bool userfaultfd_armed(struct vm_area_struct *vma)
{
return false;
}
#endif /* CONFIG_USERFAULTFD */
#endif /* _LINUX_USERFAULTFD_K_H */