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 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 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 extern int dup_userfaultfd(struct vm_area_struct *, struct list_head *); 57 extern void dup_userfaultfd_complete(struct list_head *); 58 59 extern void mremap_userfaultfd_prep(struct vm_area_struct *, 60 struct vm_userfaultfd_ctx *); 61 extern void mremap_userfaultfd_complete(struct vm_userfaultfd_ctx *, 62 unsigned long from, unsigned long to, 63 unsigned long len); 64 65 extern bool userfaultfd_remove(struct vm_area_struct *vma, 66 unsigned long start, 67 unsigned long end); 68 69 extern int userfaultfd_unmap_prep(struct vm_area_struct *vma, 70 unsigned long start, unsigned long end, 71 struct list_head *uf); 72 extern void userfaultfd_unmap_complete(struct mm_struct *mm, 73 struct list_head *uf); 74 75 #else /* CONFIG_USERFAULTFD */ 76 77 /* mm helpers */ 78 static inline int handle_userfault(struct vm_fault *vmf, unsigned long reason) 79 { 80 return VM_FAULT_SIGBUS; 81 } 82 83 static inline bool is_mergeable_vm_userfaultfd_ctx(struct vm_area_struct *vma, 84 struct vm_userfaultfd_ctx vm_ctx) 85 { 86 return true; 87 } 88 89 static inline bool userfaultfd_missing(struct vm_area_struct *vma) 90 { 91 return false; 92 } 93 94 static inline bool userfaultfd_armed(struct vm_area_struct *vma) 95 { 96 return false; 97 } 98 99 static inline int dup_userfaultfd(struct vm_area_struct *vma, 100 struct list_head *l) 101 { 102 return 0; 103 } 104 105 static inline void dup_userfaultfd_complete(struct list_head *l) 106 { 107 } 108 109 static inline void mremap_userfaultfd_prep(struct vm_area_struct *vma, 110 struct vm_userfaultfd_ctx *ctx) 111 { 112 } 113 114 static inline void mremap_userfaultfd_complete(struct vm_userfaultfd_ctx *ctx, 115 unsigned long from, 116 unsigned long to, 117 unsigned long len) 118 { 119 } 120 121 static inline bool userfaultfd_remove(struct vm_area_struct *vma, 122 unsigned long start, 123 unsigned long end) 124 { 125 return true; 126 } 127 128 static inline int userfaultfd_unmap_prep(struct vm_area_struct *vma, 129 unsigned long start, unsigned long end, 130 struct list_head *uf) 131 { 132 return 0; 133 } 134 135 static inline void userfaultfd_unmap_complete(struct mm_struct *mm, 136 struct list_head *uf) 137 { 138 } 139 140 #endif /* CONFIG_USERFAULTFD */ 141 142 #endif /* _LINUX_USERFAULTFD_K_H */ 143