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_fault *vmf, unsigned long reason); 31 32 extern ssize_t mcopy_atomic(struct mm_struct *dst_mm, unsigned long dst_start, 33 unsigned long src_start, unsigned long len); 34 extern ssize_t mfill_zeropage(struct mm_struct *dst_mm, 35 unsigned long dst_start, 36 unsigned long len); 37 38 /* mm helpers */ 39 static inline bool is_mergeable_vm_userfaultfd_ctx(struct vm_area_struct *vma, 40 struct vm_userfaultfd_ctx vm_ctx) 41 { 42 return vma->vm_userfaultfd_ctx.ctx == vm_ctx.ctx; 43 } 44 45 static inline bool userfaultfd_missing(struct vm_area_struct *vma) 46 { 47 return vma->vm_flags & VM_UFFD_MISSING; 48 } 49 50 static inline bool userfaultfd_armed(struct vm_area_struct *vma) 51 { 52 return vma->vm_flags & (VM_UFFD_MISSING | VM_UFFD_WP); 53 } 54 55 #else /* CONFIG_USERFAULTFD */ 56 57 /* mm helpers */ 58 static inline int handle_userfault(struct vm_fault *vmf, unsigned long reason) 59 { 60 return VM_FAULT_SIGBUS; 61 } 62 63 static inline bool is_mergeable_vm_userfaultfd_ctx(struct vm_area_struct *vma, 64 struct vm_userfaultfd_ctx vm_ctx) 65 { 66 return true; 67 } 68 69 static inline bool userfaultfd_missing(struct vm_area_struct *vma) 70 { 71 return false; 72 } 73 74 static inline bool userfaultfd_armed(struct vm_area_struct *vma) 75 { 76 return false; 77 } 78 79 #endif /* CONFIG_USERFAULTFD */ 80 81 #endif /* _LINUX_USERFAULTFD_K_H */ 82