include/drm/drm_vma_manager.h

   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/fs.h>
  28 #include <linux/mm.h>
  29 #include <linux/module.h>
  30 #include <linux/rbtree.h>
  31 #include <linux/spinlock.h>
  32 #include <linux/types.h>
  33
  34 struct drm_vma_offset_file {
  35         struct rb_node vm_rb;
  36         struct file *vm_filp;
  37         unsigned long vm_count;
  38 };
  39
  40 struct drm_vma_offset_node {
  41         rwlock_t vm_lock;
  42         struct drm_mm_node vm_node;
  43         struct rb_node vm_rb;
  44         struct rb_root vm_files;
  45 };
  46
  47 struct drm_vma_offset_manager {
  48         rwlock_t vm_lock;
  49         struct rb_root vm_addr_space_rb;
  50         struct drm_mm vm_addr_space_mm;
  51 };
  52
  53 void drm_vma_offset_manager_init(struct drm_vma_offset_manager *mgr,
  54                                  unsigned long page_offset, unsigned long size);
  55 void drm_vma_offset_manager_destroy(struct drm_vma_offset_manager *mgr);
  56
  57 struct drm_vma_offset_node *drm_vma_offset_lookup(struct drm_vma_offset_manager *mgr,
  58                                                   unsigned long start,
  59                                                   unsigned long pages);
  60 struct drm_vma_offset_node *drm_vma_offset_lookup_locked(struct drm_vma_offset_manager *mgr,
  61                                                            unsigned long start,
  62                                                            unsigned long pages);
  63 int drm_vma_offset_add(struct drm_vma_offset_manager *mgr,
  64                        struct drm_vma_offset_node *node, unsigned long pages);
  65 void drm_vma_offset_remove(struct drm_vma_offset_manager *mgr,
  66                            struct drm_vma_offset_node *node);
  67
  68 int drm_vma_node_allow(struct drm_vma_offset_node *node, struct file *filp);
  69 void drm_vma_node_revoke(struct drm_vma_offset_node *node, struct file *filp);
  70 bool drm_vma_node_is_allowed(struct drm_vma_offset_node *node,
  71                              struct file *filp);
  72
  73 /**
  74  * drm_vma_offset_exact_lookup() - Look up node by exact address
  75  * @mgr: Manager object
  76  * @start: Start address (page-based, not byte-based)
  77  * @pages: Size of object (page-based)
  78  *
  79  * Same as drm_vma_offset_lookup() but does not allow any offset into the node.
  80  * It only returns the exact object with the given start address.
  81  *
  82  * RETURNS:
  83  * Node at exact start address @start.
  84  */
  85 static inline struct drm_vma_offset_node *
  86 drm_vma_offset_exact_lookup(struct drm_vma_offset_manager *mgr,
  87                             unsigned long start,
  88                             unsigned long pages)
  89 {
  90         struct drm_vma_offset_node *node;
  91
  92         node = drm_vma_offset_lookup(mgr, start, pages);
  93         return (node && node->vm_node.start == start) ? node : NULL;
  94 }
  95
  96 /**
  97  * drm_vma_offset_lock_lookup() - Lock lookup for extended private use
  98  * @mgr: Manager object
  99  *
 100  * Lock VMA manager for extended lookups. Only *_locked() VMA function calls
 101  * are allowed while holding this lock. All other contexts are blocked from VMA
 102  * until the lock is released via drm_vma_offset_unlock_lookup().
 103  *
 104  * Use this if you need to take a reference to the objects returned by
 105  * drm_vma_offset_lookup_locked() before releasing this lock again.
 106  *
 107  * This lock must not be used for anything else than extended lookups. You must
 108  * not call any other VMA helpers while holding this lock.
 109  *
 110  * Note: You're in atomic-context while holding this lock!
 111  *
 112  * Example:
 113  *   drm_vma_offset_lock_lookup(mgr);
 114  *   node = drm_vma_offset_lookup_locked(mgr);
 115  *   if (node)
 116  *       kref_get_unless_zero(container_of(node, sth, entr));
 117  *   drm_vma_offset_unlock_lookup(mgr);
 118  */
 119 static inline void drm_vma_offset_lock_lookup(struct drm_vma_offset_manager *mgr)
 120 {
 121         read_lock(&mgr->vm_lock);
 122 }
 123
 124 /**
 125  * drm_vma_offset_unlock_lookup() - Unlock lookup for extended private use
 126  * @mgr: Manager object
 127  *
 128  * Release lookup-lock. See drm_vma_offset_lock_lookup() for more information.
 129  */
 130 static inline void drm_vma_offset_unlock_lookup(struct drm_vma_offset_manager *mgr)
 131 {
 132         read_unlock(&mgr->vm_lock);
 133 }
 134
 135 /**
 136  * drm_vma_node_reset() - Initialize or reset node object
 137  * @node: Node to initialize or reset
 138  *
 139  * Reset a node to its initial state. This must be called before using it with
 140  * any VMA offset manager.
 141  *
 142  * This must not be called on an already allocated node, or you will leak
 143  * memory.
 144  */
 145 static inline void drm_vma_node_reset(struct drm_vma_offset_node *node)
 146 {
 147         memset(node, 0, sizeof(*node));
 148         node->vm_files = RB_ROOT;
 149         rwlock_init(&node->vm_lock);
 150 }
 151
 152 /**
 153  * drm_vma_node_start() - Return start address for page-based addressing
 154  * @node: Node to inspect
 155  *
 156  * Return the start address of the given node. This can be used as offset into
 157  * the linear VM space that is provided by the VMA offset manager. Note that
 158  * this can only be used for page-based addressing. If you need a proper offset
 159  * for user-space mappings, you must apply "<< PAGE_SHIFT" or use the
 160  * drm_vma_node_offset_addr() helper instead.
 161  *
 162  * RETURNS:
 163  * Start address of @node for page-based addressing. 0 if the node does not
 164  * have an offset allocated.
 165  */
 166 static inline unsigned long drm_vma_node_start(struct drm_vma_offset_node *node)
 167 {
 168         return node->vm_node.start;
 169 }
 170
 171 /**
 172  * drm_vma_node_size() - Return size (page-based)
 173  * @node: Node to inspect
 174  *
 175  * Return the size as number of pages for the given node. This is the same size
 176  * that was passed to drm_vma_offset_add(). If no offset is allocated for the
 177  * node, this is 0.
 178  *
 179  * RETURNS:
 180  * Size of @node as number of pages. 0 if the node does not have an offset
 181  * allocated.
 182  */
 183 static inline unsigned long drm_vma_node_size(struct drm_vma_offset_node *node)
 184 {
 185         return node->vm_node.size;
 186 }
 187
 188 /**
 189  * drm_vma_node_has_offset() - Check whether node is added to offset manager
 190  * @node: Node to be checked
 191  *
 192  * RETURNS:
 193  * true iff the node was previously allocated an offset and added to
 194  * an vma offset manager.
 195  */
 196 static inline bool drm_vma_node_has_offset(struct drm_vma_offset_node *node)
 197 {
 198         return drm_mm_node_allocated(&node->vm_node);
 199 }
 200
 201 /**
 202  * drm_vma_node_offset_addr() - Return sanitized offset for user-space mmaps
 203  * @node: Linked offset node
 204  *
 205  * Same as drm_vma_node_start() but returns the address as a valid offset that
 206  * can be used for user-space mappings during mmap().
 207  * This must not be called on unlinked nodes.
 208  *
 209  * RETURNS:
 210  * Offset of @node for byte-based addressing. 0 if the node does not have an
 211  * object allocated.
 212  */
 213 static inline __u64 drm_vma_node_offset_addr(struct drm_vma_offset_node *node)
 214 {
 215         return ((__u64)node->vm_node.start) << PAGE_SHIFT;
 216 }
 217
 218 /**
 219  * drm_vma_node_unmap() - Unmap offset node
 220  * @node: Offset node
 221  * @file_mapping: Address space to unmap @node from
 222  *
 223  * Unmap all userspace mappings for a given offset node. The mappings must be
 224  * associated with the @file_mapping address-space. If no offset exists
 225  * nothing is done.
 226  *
 227  * This call is unlocked. The caller must guarantee that drm_vma_offset_remove()
 228  * is not called on this node concurrently.
 229  */
 230 static inline void drm_vma_node_unmap(struct drm_vma_offset_node *node,
 231                                       struct address_space *file_mapping)
 232 {
 233         if (drm_vma_node_has_offset(node))
 234                 unmap_mapping_range(file_mapping,
 235                                     drm_vma_node_offset_addr(node),
 236                                     drm_vma_node_size(node) << PAGE_SHIFT, 1);
 237 }
 238
 239 /**
 240  * drm_vma_node_verify_access() - Access verification helper for TTM
 241  * @node: Offset node
 242  * @filp: Open-file
 243  *
 244  * This checks whether @filp is granted access to @node. It is the same as
 245  * drm_vma_node_is_allowed() but suitable as drop-in helper for TTM
 246  * verify_access() callbacks.
 247  *
 248  * RETURNS:
 249  * 0 if access is granted, -EACCES otherwise.
 250  */
 251 static inline int drm_vma_node_verify_access(struct drm_vma_offset_node *node,
 252                                              struct file *filp)
 253 {
 254         return drm_vma_node_is_allowed(node, filp) ? 0 : -EACCES;
 255 }
 256
 257 #endif /* __DRM_VMA_MANAGER_H__ */