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 #include <linux/mm.h> 18 #include <asm-generic/pgtable_uffd.h> 19 20 /* 21 * CAREFUL: Check include/uapi/asm-generic/fcntl.h when defining 22 * new flags, since they might collide with O_* ones. We want 23 * to re-use O_* flags that couldn't possibly have a meaning 24 * from userfaultfd, in order to leave a free define-space for 25 * shared O_* flags. 26 */ 27 #define UFFD_CLOEXEC O_CLOEXEC 28 #define UFFD_NONBLOCK O_NONBLOCK 29 30 #define UFFD_SHARED_FCNTL_FLAGS (O_CLOEXEC | O_NONBLOCK) 31 #define UFFD_FLAGS_SET (EFD_SHARED_FCNTL_FLAGS) 32 33 extern int sysctl_unprivileged_userfaultfd; 34 35 extern vm_fault_t handle_userfault(struct vm_fault *vmf, unsigned long reason); 36 37 extern ssize_t mcopy_atomic(struct mm_struct *dst_mm, unsigned long dst_start, 38 unsigned long src_start, unsigned long len, 39 bool *mmap_changing, __u64 mode); 40 extern ssize_t mfill_zeropage(struct mm_struct *dst_mm, 41 unsigned long dst_start, 42 unsigned long len, 43 bool *mmap_changing); 44 extern int mwriteprotect_range(struct mm_struct *dst_mm, 45 unsigned long start, unsigned long len, 46 bool enable_wp, bool *mmap_changing); 47 48 /* mm helpers */ 49 static inline bool is_mergeable_vm_userfaultfd_ctx(struct vm_area_struct *vma, 50 struct vm_userfaultfd_ctx vm_ctx) 51 { 52 return vma->vm_userfaultfd_ctx.ctx == vm_ctx.ctx; 53 } 54 55 static inline bool userfaultfd_missing(struct vm_area_struct *vma) 56 { 57 return vma->vm_flags & VM_UFFD_MISSING; 58 } 59 60 static inline bool userfaultfd_wp(struct vm_area_struct *vma) 61 { 62 return vma->vm_flags & VM_UFFD_WP; 63 } 64 65 static inline bool userfaultfd_pte_wp(struct vm_area_struct *vma, 66 pte_t pte) 67 { 68 return userfaultfd_wp(vma) && pte_uffd_wp(pte); 69 } 70 71 static inline bool userfaultfd_huge_pmd_wp(struct vm_area_struct *vma, 72 pmd_t pmd) 73 { 74 return userfaultfd_wp(vma) && pmd_uffd_wp(pmd); 75 } 76 77 static inline bool userfaultfd_armed(struct vm_area_struct *vma) 78 { 79 return vma->vm_flags & (VM_UFFD_MISSING | VM_UFFD_WP); 80 } 81 82 extern int dup_userfaultfd(struct vm_area_struct *, struct list_head *); 83 extern void dup_userfaultfd_complete(struct list_head *); 84 85 extern void mremap_userfaultfd_prep(struct vm_area_struct *, 86 struct vm_userfaultfd_ctx *); 87 extern void mremap_userfaultfd_complete(struct vm_userfaultfd_ctx *, 88 unsigned long from, unsigned long to, 89 unsigned long len); 90 91 extern bool userfaultfd_remove(struct vm_area_struct *vma, 92 unsigned long start, 93 unsigned long end); 94 95 extern int userfaultfd_unmap_prep(struct vm_area_struct *vma, 96 unsigned long start, unsigned long end, 97 struct list_head *uf); 98 extern void userfaultfd_unmap_complete(struct mm_struct *mm, 99 struct list_head *uf); 100 101 #else /* CONFIG_USERFAULTFD */ 102 103 /* mm helpers */ 104 static inline vm_fault_t handle_userfault(struct vm_fault *vmf, 105 unsigned long reason) 106 { 107 return VM_FAULT_SIGBUS; 108 } 109 110 static inline bool is_mergeable_vm_userfaultfd_ctx(struct vm_area_struct *vma, 111 struct vm_userfaultfd_ctx vm_ctx) 112 { 113 return true; 114 } 115 116 static inline bool userfaultfd_missing(struct vm_area_struct *vma) 117 { 118 return false; 119 } 120 121 static inline bool userfaultfd_wp(struct vm_area_struct *vma) 122 { 123 return false; 124 } 125 126 static inline bool userfaultfd_pte_wp(struct vm_area_struct *vma, 127 pte_t pte) 128 { 129 return false; 130 } 131 132 static inline bool userfaultfd_huge_pmd_wp(struct vm_area_struct *vma, 133 pmd_t pmd) 134 { 135 return false; 136 } 137 138 139 static inline bool userfaultfd_armed(struct vm_area_struct *vma) 140 { 141 return false; 142 } 143 144 static inline int dup_userfaultfd(struct vm_area_struct *vma, 145 struct list_head *l) 146 { 147 return 0; 148 } 149 150 static inline void dup_userfaultfd_complete(struct list_head *l) 151 { 152 } 153 154 static inline void mremap_userfaultfd_prep(struct vm_area_struct *vma, 155 struct vm_userfaultfd_ctx *ctx) 156 { 157 } 158 159 static inline void mremap_userfaultfd_complete(struct vm_userfaultfd_ctx *ctx, 160 unsigned long from, 161 unsigned long to, 162 unsigned long len) 163 { 164 } 165 166 static inline bool userfaultfd_remove(struct vm_area_struct *vma, 167 unsigned long start, 168 unsigned long end) 169 { 170 return true; 171 } 172 173 static inline int userfaultfd_unmap_prep(struct vm_area_struct *vma, 174 unsigned long start, unsigned long end, 175 struct list_head *uf) 176 { 177 return 0; 178 } 179 180 static inline void userfaultfd_unmap_complete(struct mm_struct *mm, 181 struct list_head *uf) 182 { 183 } 184 185 #endif /* CONFIG_USERFAULTFD */ 186 187 #endif /* _LINUX_USERFAULTFD_K_H */ 188