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 int sysctl_unprivileged_userfaultfd; 32 33 extern vm_fault_t handle_userfault(struct vm_fault *vmf, unsigned long reason); 34 35 extern ssize_t mcopy_atomic(struct mm_struct *dst_mm, unsigned long dst_start, 36 unsigned long src_start, unsigned long len, 37 bool *mmap_changing); 38 extern ssize_t mfill_zeropage(struct mm_struct *dst_mm, 39 unsigned long dst_start, 40 unsigned long len, 41 bool *mmap_changing); 42 43 /* mm helpers */ 44 static inline bool is_mergeable_vm_userfaultfd_ctx(struct vm_area_struct *vma, 45 struct vm_userfaultfd_ctx vm_ctx) 46 { 47 return vma->vm_userfaultfd_ctx.ctx == vm_ctx.ctx; 48 } 49 50 static inline bool userfaultfd_missing(struct vm_area_struct *vma) 51 { 52 return vma->vm_flags & VM_UFFD_MISSING; 53 } 54 55 static inline bool userfaultfd_armed(struct vm_area_struct *vma) 56 { 57 return vma->vm_flags & (VM_UFFD_MISSING | VM_UFFD_WP); 58 } 59 60 extern int dup_userfaultfd(struct vm_area_struct *, struct list_head *); 61 extern void dup_userfaultfd_complete(struct list_head *); 62 63 extern void mremap_userfaultfd_prep(struct vm_area_struct *, 64 struct vm_userfaultfd_ctx *); 65 extern void mremap_userfaultfd_complete(struct vm_userfaultfd_ctx *, 66 unsigned long from, unsigned long to, 67 unsigned long len); 68 69 extern bool userfaultfd_remove(struct vm_area_struct *vma, 70 unsigned long start, 71 unsigned long end); 72 73 extern int userfaultfd_unmap_prep(struct vm_area_struct *vma, 74 unsigned long start, unsigned long end, 75 struct list_head *uf); 76 extern void userfaultfd_unmap_complete(struct mm_struct *mm, 77 struct list_head *uf); 78 79 #else /* CONFIG_USERFAULTFD */ 80 81 /* mm helpers */ 82 static inline vm_fault_t handle_userfault(struct vm_fault *vmf, 83 unsigned long reason) 84 { 85 return VM_FAULT_SIGBUS; 86 } 87 88 static inline bool is_mergeable_vm_userfaultfd_ctx(struct vm_area_struct *vma, 89 struct vm_userfaultfd_ctx vm_ctx) 90 { 91 return true; 92 } 93 94 static inline bool userfaultfd_missing(struct vm_area_struct *vma) 95 { 96 return false; 97 } 98 99 static inline bool userfaultfd_armed(struct vm_area_struct *vma) 100 { 101 return false; 102 } 103 104 static inline int dup_userfaultfd(struct vm_area_struct *vma, 105 struct list_head *l) 106 { 107 return 0; 108 } 109 110 static inline void dup_userfaultfd_complete(struct list_head *l) 111 { 112 } 113 114 static inline void mremap_userfaultfd_prep(struct vm_area_struct *vma, 115 struct vm_userfaultfd_ctx *ctx) 116 { 117 } 118 119 static inline void mremap_userfaultfd_complete(struct vm_userfaultfd_ctx *ctx, 120 unsigned long from, 121 unsigned long to, 122 unsigned long len) 123 { 124 } 125 126 static inline bool userfaultfd_remove(struct vm_area_struct *vma, 127 unsigned long start, 128 unsigned long end) 129 { 130 return true; 131 } 132 133 static inline int userfaultfd_unmap_prep(struct vm_area_struct *vma, 134 unsigned long start, unsigned long end, 135 struct list_head *uf) 136 { 137 return 0; 138 } 139 140 static inline void userfaultfd_unmap_complete(struct mm_struct *mm, 141 struct list_head *uf) 142 { 143 } 144 145 #endif /* CONFIG_USERFAULTFD */ 146 147 #endif /* _LINUX_USERFAULTFD_K_H */ 148