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drm_vma_manager.h revision 1.2
      1 /*	$NetBSD: drm_vma_manager.h,v 1.2 2018/08/27 04:58:38 riastradh Exp $	*/
      2 
      3 #ifndef __DRM_VMA_MANAGER_H__
      4 #define __DRM_VMA_MANAGER_H__
      5 
      6 /*
      7  * Copyright (c) 2013 David Herrmann <dh.herrmann (at) gmail.com>
      8  *
      9  * Permission is hereby granted, free of charge, to any person obtaining a
     10  * copy of this software and associated documentation files (the "Software"),
     11  * to deal in the Software without restriction, including without limitation
     12  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
     13  * and/or sell copies of the Software, and to permit persons to whom the
     14  * Software is furnished to do so, subject to the following conditions:
     15  *
     16  * The above copyright notice and this permission notice shall be included in
     17  * all copies or substantial portions of the Software.
     18  *
     19  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
     20  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
     21  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
     22  * THE COPYRIGHT HOLDER(S) OR AUTHOR(S) BE LIABLE FOR ANY CLAIM, DAMAGES OR
     23  * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
     24  * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
     25  * OTHER DEALINGS IN THE SOFTWARE.
     26  */
     27 
     28 #include <drm/drm_mm.h>
     29 #include <linux/fs.h>
     30 #include <linux/mm.h>
     31 #include <linux/module.h>
     32 #include <linux/rbtree.h>
     33 #include <linux/spinlock.h>
     34 #include <linux/types.h>
     35 
     36 struct drm_vma_offset_file {
     37 	struct rb_node vm_rb;
     38 	struct file *vm_filp;
     39 	unsigned long vm_count;
     40 };
     41 
     42 struct drm_vma_offset_node {
     43 	rwlock_t vm_lock;
     44 	struct drm_mm_node vm_node;
     45 	struct rb_node vm_rb;
     46 	struct rb_root vm_files;
     47 };
     48 
     49 struct drm_vma_offset_manager {
     50 	rwlock_t vm_lock;
     51 	struct rb_root vm_addr_space_rb;
     52 	struct drm_mm vm_addr_space_mm;
     53 };
     54 
     55 void drm_vma_offset_manager_init(struct drm_vma_offset_manager *mgr,
     56 				 unsigned long page_offset, unsigned long size);
     57 void drm_vma_offset_manager_destroy(struct drm_vma_offset_manager *mgr);
     58 
     59 struct drm_vma_offset_node *drm_vma_offset_lookup_locked(struct drm_vma_offset_manager *mgr,
     60 							   unsigned long start,
     61 							   unsigned long pages);
     62 int drm_vma_offset_add(struct drm_vma_offset_manager *mgr,
     63 		       struct drm_vma_offset_node *node, unsigned long pages);
     64 void drm_vma_offset_remove(struct drm_vma_offset_manager *mgr,
     65 			   struct drm_vma_offset_node *node);
     66 
     67 int drm_vma_node_allow(struct drm_vma_offset_node *node, struct file *filp);
     68 void drm_vma_node_revoke(struct drm_vma_offset_node *node, struct file *filp);
     69 bool drm_vma_node_is_allowed(struct drm_vma_offset_node *node,
     70 			     struct file *filp);
     71 
     72 /**
     73  * drm_vma_offset_exact_lookup_locked() - Look up node by exact address
     74  * @mgr: Manager object
     75  * @start: Start address (page-based, not byte-based)
     76  * @pages: Size of object (page-based)
     77  *
     78  * Same as drm_vma_offset_lookup_locked() but does not allow any offset into the node.
     79  * It only returns the exact object with the given start address.
     80  *
     81  * RETURNS:
     82  * Node at exact start address @start.
     83  */
     84 static inline struct drm_vma_offset_node *
     85 drm_vma_offset_exact_lookup_locked(struct drm_vma_offset_manager *mgr,
     86 				   unsigned long start,
     87 				   unsigned long pages)
     88 {
     89 	struct drm_vma_offset_node *node;
     90 
     91 	node = drm_vma_offset_lookup_locked(mgr, start, pages);
     92 	return (node && node->vm_node.start == start) ? node : NULL;
     93 }
     94 
     95 /**
     96  * drm_vma_offset_lock_lookup() - Lock lookup for extended private use
     97  * @mgr: Manager object
     98  *
     99  * Lock VMA manager for extended lookups. Only locked VMA function calls
    100  * are allowed while holding this lock. All other contexts are blocked from VMA
    101  * until the lock is released via drm_vma_offset_unlock_lookup().
    102  *
    103  * Use this if you need to take a reference to the objects returned by
    104  * drm_vma_offset_lookup_locked() before releasing this lock again.
    105  *
    106  * This lock must not be used for anything else than extended lookups. You must
    107  * not call any other VMA helpers while holding this lock.
    108  *
    109  * Note: You're in atomic-context while holding this lock!
    110  */
    111 static inline void drm_vma_offset_lock_lookup(struct drm_vma_offset_manager *mgr)
    112 {
    113 	read_lock(&mgr->vm_lock);
    114 }
    115 
    116 /**
    117  * drm_vma_offset_unlock_lookup() - Unlock lookup for extended private use
    118  * @mgr: Manager object
    119  *
    120  * Release lookup-lock. See drm_vma_offset_lock_lookup() for more information.
    121  */
    122 static inline void drm_vma_offset_unlock_lookup(struct drm_vma_offset_manager *mgr)
    123 {
    124 	read_unlock(&mgr->vm_lock);
    125 }
    126 
    127 /**
    128  * drm_vma_node_reset() - Initialize or reset node object
    129  * @node: Node to initialize or reset
    130  *
    131  * Reset a node to its initial state. This must be called before using it with
    132  * any VMA offset manager.
    133  *
    134  * This must not be called on an already allocated node, or you will leak
    135  * memory.
    136  */
    137 static inline void drm_vma_node_reset(struct drm_vma_offset_node *node)
    138 {
    139 	memset(node, 0, sizeof(*node));
    140 	node->vm_files = RB_ROOT;
    141 	rwlock_init(&node->vm_lock);
    142 }
    143 
    144 /**
    145  * drm_vma_node_start() - Return start address for page-based addressing
    146  * @node: Node to inspect
    147  *
    148  * Return the start address of the given node. This can be used as offset into
    149  * the linear VM space that is provided by the VMA offset manager. Note that
    150  * this can only be used for page-based addressing. If you need a proper offset
    151  * for user-space mappings, you must apply "<< PAGE_SHIFT" or use the
    152  * drm_vma_node_offset_addr() helper instead.
    153  *
    154  * RETURNS:
    155  * Start address of @node for page-based addressing. 0 if the node does not
    156  * have an offset allocated.
    157  */
    158 static inline unsigned long drm_vma_node_start(struct drm_vma_offset_node *node)
    159 {
    160 	return node->vm_node.start;
    161 }
    162 
    163 /**
    164  * drm_vma_node_size() - Return size (page-based)
    165  * @node: Node to inspect
    166  *
    167  * Return the size as number of pages for the given node. This is the same size
    168  * that was passed to drm_vma_offset_add(). If no offset is allocated for the
    169  * node, this is 0.
    170  *
    171  * RETURNS:
    172  * Size of @node as number of pages. 0 if the node does not have an offset
    173  * allocated.
    174  */
    175 static inline unsigned long drm_vma_node_size(struct drm_vma_offset_node *node)
    176 {
    177 	return node->vm_node.size;
    178 }
    179 
    180 /**
    181  * drm_vma_node_has_offset() - Check whether node is added to offset manager
    182  * @node: Node to be checked
    183  *
    184  * RETURNS:
    185  * true iff the node was previously allocated an offset and added to
    186  * an vma offset manager.
    187  */
    188 static inline bool drm_vma_node_has_offset(struct drm_vma_offset_node *node)
    189 {
    190 	return drm_mm_node_allocated(&node->vm_node);
    191 }
    192 
    193 /**
    194  * drm_vma_node_offset_addr() - Return sanitized offset for user-space mmaps
    195  * @node: Linked offset node
    196  *
    197  * Same as drm_vma_node_start() but returns the address as a valid offset that
    198  * can be used for user-space mappings during mmap().
    199  * This must not be called on unlinked nodes.
    200  *
    201  * RETURNS:
    202  * Offset of @node for byte-based addressing. 0 if the node does not have an
    203  * object allocated.
    204  */
    205 static inline __u64 drm_vma_node_offset_addr(struct drm_vma_offset_node *node)
    206 {
    207 	return ((__u64)node->vm_node.start) << PAGE_SHIFT;
    208 }
    209 
    210 /**
    211  * drm_vma_node_unmap() - Unmap offset node
    212  * @node: Offset node
    213  * @file_mapping: Address space to unmap @node from
    214  *
    215  * Unmap all userspace mappings for a given offset node. The mappings must be
    216  * associated with the @file_mapping address-space. If no offset exists
    217  * nothing is done.
    218  *
    219  * This call is unlocked. The caller must guarantee that drm_vma_offset_remove()
    220  * is not called on this node concurrently.
    221  */
    222 static inline void drm_vma_node_unmap(struct drm_vma_offset_node *node,
    223 				      struct address_space *file_mapping)
    224 {
    225 	if (drm_vma_node_has_offset(node))
    226 		unmap_mapping_range(file_mapping,
    227 				    drm_vma_node_offset_addr(node),
    228 				    drm_vma_node_size(node) << PAGE_SHIFT, 1);
    229 }
    230 
    231 /**
    232  * drm_vma_node_verify_access() - Access verification helper for TTM
    233  * @node: Offset node
    234  * @filp: Open-file
    235  *
    236  * This checks whether @filp is granted access to @node. It is the same as
    237  * drm_vma_node_is_allowed() but suitable as drop-in helper for TTM
    238  * verify_access() callbacks.
    239  *
    240  * RETURNS:
    241  * 0 if access is granted, -EACCES otherwise.
    242  */
    243 static inline int drm_vma_node_verify_access(struct drm_vma_offset_node *node,
    244 					     struct file *filp)
    245 {
    246 	return drm_vma_node_is_allowed(node, filp) ? 0 : -EACCES;
    247 }
    248 
    249 #endif /* __DRM_VMA_MANAGER_H__ */
    250