1 /* SPDX-License-Identifier: GPL-2.0 */ 2 /* 3 * include/linux/userfaultfd_k.h 4 * 5 * Copyright (C) 2015 Red Hat, Inc. 6 * 7 */ 8 9 #ifndef _LINUX_USERFAULTFD_K_H 10 #define _LINUX_USERFAULTFD_K_H 11 12 #ifdef CONFIG_USERFAULTFD 13 14 #include <linux/userfaultfd.h> /* linux/include/uapi/linux/userfaultfd.h */ 15 16 #include <linux/fcntl.h> 17 18 /* 19 * CAREFUL: Check include/uapi/asm-generic/fcntl.h when defining 20 * new flags, since they might collide with O_* ones. We want 21 * to re-use O_* flags that couldn't possibly have a meaning 22 * from userfaultfd, in order to leave a free define-space for 23 * shared O_* flags. 24 */ 25 #define UFFD_CLOEXEC O_CLOEXEC 26 #define UFFD_NONBLOCK O_NONBLOCK 27 28 #define UFFD_SHARED_FCNTL_FLAGS (O_CLOEXEC | O_NONBLOCK) 29 #define UFFD_FLAGS_SET (EFD_SHARED_FCNTL_FLAGS) 30 31 extern vm_fault_t handle_userfault(struct vm_fault *vmf, 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 bool *mmap_changing); 36 extern ssize_t mfill_zeropage(struct mm_struct *dst_mm, 37 unsigned long dst_start, 38 unsigned long len, 39 bool *mmap_changing); 40 41 /* mm helpers */ 42 static inline bool is_mergeable_vm_userfaultfd_ctx(struct vm_area_struct *vma, 43 struct vm_userfaultfd_ctx vm_ctx) 44 { 45 return vma->vm_userfaultfd_ctx.ctx == vm_ctx.ctx; 46 } 47 48 static inline bool userfaultfd_missing(struct vm_area_struct *vma) 49 { 50 return vma->vm_flags & VM_UFFD_MISSING; 51 } 52 53 static inline bool userfaultfd_armed(struct vm_area_struct *vma) 54 { 55 return vma->vm_flags & (VM_UFFD_MISSING | VM_UFFD_WP); 56 } 57 58 extern int dup_userfaultfd(struct vm_area_struct *, struct list_head *); 59 extern void dup_userfaultfd_complete(struct list_head *); 60 61 extern void mremap_userfaultfd_prep(struct vm_area_struct *, 62 struct vm_userfaultfd_ctx *); 63 extern void mremap_userfaultfd_complete(struct vm_userfaultfd_ctx *, 64 unsigned long from, unsigned long to, 65 unsigned long len); 66 67 extern bool userfaultfd_remove(struct vm_area_struct *vma, 68 unsigned long start, 69 unsigned long end); 70 71 extern int userfaultfd_unmap_prep(struct vm_area_struct *vma, 72 unsigned long start, unsigned long end, 73 struct list_head *uf); 74 extern void userfaultfd_unmap_complete(struct mm_struct *mm, 75 struct list_head *uf); 76 77 #else /* CONFIG_USERFAULTFD */ 78 79 /* mm helpers */ 80 static inline vm_fault_t handle_userfault(struct vm_fault *vmf, 81 unsigned long reason) 82 { 83 return VM_FAULT_SIGBUS; 84 } 85 86 static inline bool is_mergeable_vm_userfaultfd_ctx(struct vm_area_struct *vma, 87 struct vm_userfaultfd_ctx vm_ctx) 88 { 89 return true; 90 } 91 92 static inline bool userfaultfd_missing(struct vm_area_struct *vma) 93 { 94 return false; 95 } 96 97 static inline bool userfaultfd_armed(struct vm_area_struct *vma) 98 { 99 return false; 100 } 101 102 static inline int dup_userfaultfd(struct vm_area_struct *vma, 103 struct list_head *l) 104 { 105 return 0; 106 } 107 108 static inline void dup_userfaultfd_complete(struct list_head *l) 109 { 110 } 111 112 static inline void mremap_userfaultfd_prep(struct vm_area_struct *vma, 113 struct vm_userfaultfd_ctx *ctx) 114 { 115 } 116 117 static inline void mremap_userfaultfd_complete(struct vm_userfaultfd_ctx *ctx, 118 unsigned long from, 119 unsigned long to, 120 unsigned long len) 121 { 122 } 123 124 static inline bool userfaultfd_remove(struct vm_area_struct *vma, 125 unsigned long start, 126 unsigned long end) 127 { 128 return true; 129 } 130 131 static inline int userfaultfd_unmap_prep(struct vm_area_struct *vma, 132 unsigned long start, unsigned long end, 133 struct list_head *uf) 134 { 135 return 0; 136 } 137 138 static inline void userfaultfd_unmap_complete(struct mm_struct *mm, 139 struct list_head *uf) 140 { 141 } 142 143 #endif /* CONFIG_USERFAULTFD */ 144 145 #endif /* _LINUX_USERFAULTFD_K_H */ 146