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