1/* 2 * include/linux/userfaultfd_k.h 3 * 4 * Copyright (C) 2015 Red Hat, Inc. 5 * 6 */ 7 8#ifndef _LINUX_USERFAULTFD_K_H 9#define _LINUX_USERFAULTFD_K_H 10 11#ifdef CONFIG_USERFAULTFD 12 13#include <linux/userfaultfd.h> /* linux/include/uapi/linux/userfaultfd.h */ 14 15#include <linux/fcntl.h> 16 17/* 18 * CAREFUL: Check include/uapi/asm-generic/fcntl.h when defining 19 * new flags, since they might collide with O_* ones. We want 20 * to re-use O_* flags that couldn't possibly have a meaning 21 * from userfaultfd, in order to leave a free define-space for 22 * shared O_* flags. 23 */ 24#define UFFD_CLOEXEC O_CLOEXEC 25#define UFFD_NONBLOCK O_NONBLOCK 26 27#define UFFD_SHARED_FCNTL_FLAGS (O_CLOEXEC | O_NONBLOCK) 28#define UFFD_FLAGS_SET (EFD_SHARED_FCNTL_FLAGS) 29 30extern int handle_userfault(struct vm_area_struct *vma, unsigned long address, 31 unsigned int flags, unsigned long reason); 32 33extern ssize_t mcopy_atomic(struct mm_struct *dst_mm, unsigned long dst_start, 34 unsigned long src_start, unsigned long len); 35extern ssize_t mfill_zeropage(struct mm_struct *dst_mm, 36 unsigned long dst_start, 37 unsigned long len); 38 39/* mm helpers */ 40static inline bool is_mergeable_vm_userfaultfd_ctx(struct vm_area_struct *vma, 41 struct vm_userfaultfd_ctx vm_ctx) 42{ 43 return vma->vm_userfaultfd_ctx.ctx == vm_ctx.ctx; 44} 45 46static inline bool userfaultfd_missing(struct vm_area_struct *vma) 47{ 48 return vma->vm_flags & VM_UFFD_MISSING; 49} 50 51static inline bool userfaultfd_armed(struct vm_area_struct *vma) 52{ 53 return vma->vm_flags & (VM_UFFD_MISSING | VM_UFFD_WP); 54} 55 56#else /* CONFIG_USERFAULTFD */ 57 58/* mm helpers */ 59static inline int handle_userfault(struct vm_area_struct *vma, 60 unsigned long address, 61 unsigned int flags, 62 unsigned long reason) 63{ 64 return VM_FAULT_SIGBUS; 65} 66 67static inline bool is_mergeable_vm_userfaultfd_ctx(struct vm_area_struct *vma, 68 struct vm_userfaultfd_ctx vm_ctx) 69{ 70 return true; 71} 72 73static inline bool userfaultfd_missing(struct vm_area_struct *vma) 74{ 75 return false; 76} 77 78static inline bool userfaultfd_armed(struct vm_area_struct *vma) 79{ 80 return false; 81} 82 83#endif /* CONFIG_USERFAULTFD */ 84 85#endif /* _LINUX_USERFAULTFD_K_H */ 86