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 30 extern int handle_userfault(struct vm_area_struct *vma, unsigned long address, 31 unsigned int flags, unsigned long reason); 32 33 extern ssize_t mcopy_atomic(struct mm_struct *dst_mm, unsigned long dst_start, 34 unsigned long src_start, unsigned long len); 35 extern ssize_t mfill_zeropage(struct mm_struct *dst_mm, 36 unsigned long dst_start, 37 unsigned long len); 38 39 /* mm helpers */ 40 static 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 46 static inline bool userfaultfd_missing(struct vm_area_struct *vma) 47 { 48 return vma->vm_flags & VM_UFFD_MISSING; 49 } 50 51 static 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 */ 59 static 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 67 static 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 73 static inline bool userfaultfd_missing(struct vm_area_struct *vma) 74 { 75 return false; 76 } 77 78 static 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