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 /* 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__ */