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