1 #ifndef __DRM_VMA_MANAGER_H__ 2 #define __DRM_VMA_MANAGER_H__ 3 4 /* 5 * Copyright (c) 2013 David Herrmann <dh.herrmann@gmail.com> 6 * 7 * Permission is hereby granted, free of charge, to any person obtaining a 8 * copy of this software and associated documentation files (the "Software"), 9 * to deal in the Software without restriction, including without limitation 10 * the rights to use, copy, modify, merge, publish, distribute, sublicense, 11 * and/or sell copies of the Software, and to permit persons to whom the 12 * Software is furnished to do so, subject to the following conditions: 13 * 14 * The above copyright notice and this permission notice shall be included in 15 * all copies or substantial portions of the Software. 16 * 17 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR 18 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, 19 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL 20 * THE COPYRIGHT HOLDER(S) OR AUTHOR(S) BE LIABLE FOR ANY CLAIM, DAMAGES OR 21 * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, 22 * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR 23 * OTHER DEALINGS IN THE SOFTWARE. 24 */ 25 26 #include <drm/drm_mm.h> 27 #include <linux/mm.h> 28 #include <linux/rbtree.h> 29 #include <linux/spinlock.h> 30 #include <linux/types.h> 31 32 /* We make up offsets for buffer objects so we can recognize them at 33 * mmap time. pgoff in mmap is an unsigned long, so we need to make sure 34 * that the faked up offset will fit 35 */ 36 #if BITS_PER_LONG == 64 37 #define DRM_FILE_PAGE_OFFSET_START ((0xFFFFFFFFUL >> PAGE_SHIFT) + 1) 38 #define DRM_FILE_PAGE_OFFSET_SIZE ((0xFFFFFFFFUL >> PAGE_SHIFT) * 256) 39 #else 40 #define DRM_FILE_PAGE_OFFSET_START ((0xFFFFFFFUL >> PAGE_SHIFT) + 1) 41 #define DRM_FILE_PAGE_OFFSET_SIZE ((0xFFFFFFFUL >> PAGE_SHIFT) * 16) 42 #endif 43 44 struct drm_file; 45 46 struct drm_vma_offset_file { 47 struct rb_node vm_rb; 48 struct drm_file *vm_tag; 49 unsigned long vm_count; 50 }; 51 52 struct drm_vma_offset_node { 53 rwlock_t vm_lock; 54 struct drm_mm_node vm_node; 55 struct rb_root vm_files; 56 bool readonly:1; 57 }; 58 59 struct drm_vma_offset_manager { 60 rwlock_t vm_lock; 61 struct drm_mm vm_addr_space_mm; 62 }; 63 64 void drm_vma_offset_manager_init(struct drm_vma_offset_manager *mgr, 65 unsigned long page_offset, unsigned long size); 66 void drm_vma_offset_manager_destroy(struct drm_vma_offset_manager *mgr); 67 68 struct drm_vma_offset_node *drm_vma_offset_lookup_locked(struct drm_vma_offset_manager *mgr, 69 unsigned long start, 70 unsigned long pages); 71 int drm_vma_offset_add(struct drm_vma_offset_manager *mgr, 72 struct drm_vma_offset_node *node, unsigned long pages); 73 void drm_vma_offset_remove(struct drm_vma_offset_manager *mgr, 74 struct drm_vma_offset_node *node); 75 76 int drm_vma_node_allow(struct drm_vma_offset_node *node, struct drm_file *tag); 77 void drm_vma_node_revoke(struct drm_vma_offset_node *node, 78 struct drm_file *tag); 79 bool drm_vma_node_is_allowed(struct drm_vma_offset_node *node, 80 struct drm_file *tag); 81 82 /** 83 * drm_vma_offset_exact_lookup_locked() - Look up node by exact address 84 * @mgr: Manager object 85 * @start: Start address (page-based, not byte-based) 86 * @pages: Size of object (page-based) 87 * 88 * Same as drm_vma_offset_lookup_locked() but does not allow any offset into the node. 89 * It only returns the exact object with the given start address. 90 * 91 * RETURNS: 92 * Node at exact start address @start. 93 */ 94 static inline struct drm_vma_offset_node * 95 drm_vma_offset_exact_lookup_locked(struct drm_vma_offset_manager *mgr, 96 unsigned long start, 97 unsigned long pages) 98 { 99 struct drm_vma_offset_node *node; 100 101 node = drm_vma_offset_lookup_locked(mgr, start, pages); 102 return (node && node->vm_node.start == start) ? node : NULL; 103 } 104 105 /** 106 * drm_vma_offset_lock_lookup() - Lock lookup for extended private use 107 * @mgr: Manager object 108 * 109 * Lock VMA manager for extended lookups. Only locked VMA function calls 110 * are allowed while holding this lock. All other contexts are blocked from VMA 111 * until the lock is released via drm_vma_offset_unlock_lookup(). 112 * 113 * Use this if you need to take a reference to the objects returned by 114 * drm_vma_offset_lookup_locked() before releasing this lock again. 115 * 116 * This lock must not be used for anything else than extended lookups. You must 117 * not call any other VMA helpers while holding this lock. 118 * 119 * Note: You're in atomic-context while holding this lock! 120 */ 121 static inline void drm_vma_offset_lock_lookup(struct drm_vma_offset_manager *mgr) 122 { 123 read_lock(&mgr->vm_lock); 124 } 125 126 /** 127 * drm_vma_offset_unlock_lookup() - Unlock lookup for extended private use 128 * @mgr: Manager object 129 * 130 * Release lookup-lock. See drm_vma_offset_lock_lookup() for more information. 131 */ 132 static inline void drm_vma_offset_unlock_lookup(struct drm_vma_offset_manager *mgr) 133 { 134 read_unlock(&mgr->vm_lock); 135 } 136 137 /** 138 * drm_vma_node_reset() - Initialize or reset node object 139 * @node: Node to initialize or reset 140 * 141 * Reset a node to its initial state. This must be called before using it with 142 * any VMA offset manager. 143 * 144 * This must not be called on an already allocated node, or you will leak 145 * memory. 146 */ 147 static inline void drm_vma_node_reset(struct drm_vma_offset_node *node) 148 { 149 memset(node, 0, sizeof(*node)); 150 node->vm_files = RB_ROOT; 151 rwlock_init(&node->vm_lock); 152 } 153 154 /** 155 * drm_vma_node_start() - Return start address for page-based addressing 156 * @node: Node to inspect 157 * 158 * Return the start address of the given node. This can be used as offset into 159 * the linear VM space that is provided by the VMA offset manager. Note that 160 * this can only be used for page-based addressing. If you need a proper offset 161 * for user-space mappings, you must apply "<< PAGE_SHIFT" or use the 162 * drm_vma_node_offset_addr() helper instead. 163 * 164 * RETURNS: 165 * Start address of @node for page-based addressing. 0 if the node does not 166 * have an offset allocated. 167 */ 168 static inline unsigned long drm_vma_node_start(const struct drm_vma_offset_node *node) 169 { 170 return node->vm_node.start; 171 } 172 173 /** 174 * drm_vma_node_size() - Return size (page-based) 175 * @node: Node to inspect 176 * 177 * Return the size as number of pages for the given node. This is the same size 178 * that was passed to drm_vma_offset_add(). If no offset is allocated for the 179 * node, this is 0. 180 * 181 * RETURNS: 182 * Size of @node as number of pages. 0 if the node does not have an offset 183 * allocated. 184 */ 185 static inline unsigned long drm_vma_node_size(struct drm_vma_offset_node *node) 186 { 187 return node->vm_node.size; 188 } 189 190 /** 191 * drm_vma_node_offset_addr() - Return sanitized offset for user-space mmaps 192 * @node: Linked offset node 193 * 194 * Same as drm_vma_node_start() but returns the address as a valid offset that 195 * can be used for user-space mappings during mmap(). 196 * This must not be called on unlinked nodes. 197 * 198 * RETURNS: 199 * Offset of @node for byte-based addressing. 0 if the node does not have an 200 * object allocated. 201 */ 202 static inline __u64 drm_vma_node_offset_addr(struct drm_vma_offset_node *node) 203 { 204 return ((__u64)node->vm_node.start) << PAGE_SHIFT; 205 } 206 207 /** 208 * drm_vma_node_unmap() - Unmap offset node 209 * @node: Offset node 210 * @file_mapping: Address space to unmap @node from 211 * 212 * Unmap all userspace mappings for a given offset node. The mappings must be 213 * associated with the @file_mapping address-space. If no offset exists 214 * nothing is done. 215 * 216 * This call is unlocked. The caller must guarantee that drm_vma_offset_remove() 217 * is not called on this node concurrently. 218 */ 219 static inline void drm_vma_node_unmap(struct drm_vma_offset_node *node, 220 struct address_space *file_mapping) 221 { 222 if (drm_mm_node_allocated(&node->vm_node)) 223 unmap_mapping_range(file_mapping, 224 drm_vma_node_offset_addr(node), 225 drm_vma_node_size(node) << PAGE_SHIFT, 1); 226 } 227 228 /** 229 * drm_vma_node_verify_access() - Access verification helper for TTM 230 * @node: Offset node 231 * @tag: Tag of file to check 232 * 233 * This checks whether @tag is granted access to @node. It is the same as 234 * drm_vma_node_is_allowed() but suitable as drop-in helper for TTM 235 * verify_access() callbacks. 236 * 237 * RETURNS: 238 * 0 if access is granted, -EACCES otherwise. 239 */ 240 static inline int drm_vma_node_verify_access(struct drm_vma_offset_node *node, 241 struct drm_file *tag) 242 { 243 return drm_vma_node_is_allowed(node, tag) ? 0 : -EACCES; 244 } 245 246 #endif /* __DRM_VMA_MANAGER_H__ */ 247