1 // SPDX-License-Identifier: GPL-2.0 OR MIT
3  * Copyright (c) 2006-2009 VMware, Inc., Palo Alto, CA., USA
8  * copy of this software and associated documentation files (the "Software"),
9  * to deal in the Software without restriction, including without limitation
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:
15  * all copies or substantial portions of the Software.
17  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
22  * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
23  * OTHER DEALINGS IN THE SOFTWARE.
39  * The vma-manager is responsible to map arbitrary driver-dependent memory
40  * regions into the linear user address-space. It provides offsets to the
41  * caller which can then be used on the address_space of the drm-device. It
43  * confuse mm-core by inconsistent fake vm_pgoff fields.
45  * only be used to manage mappings into linear user-space VMs.
48  * optimized for alloc/free calls, not lookups. Hence, we use an rb-tree to
52  * Otherwise, mm-core will be unable to tear down memory mappings as the VM will
55  * This offset manager works on page-based addresses. That is, every argument
58  * must always be page-aligned (as usual).
59  * If you want to get a valid byte-based user-space address for a given offset,
63  * management. For every open-file context that is allowed to access a given
65  * open-file with the offset of the node will fail with -EACCES. To revoke
71  * drm_vma_offset_manager_init - Initialize new offset-manager
73  * @page_offset: Offset of available memory area (page-based)
74  * @size: Size of available address space range (page-based)
76  * Initialize a new offset-manager. The offset and area size available for the
78  * page-numbers, not bytes.
82  * for the caller. While calling into the vma-manager, a given node must
88 	rwlock_init(&mgr->vm_lock);  in drm_vma_offset_manager_init()
89 	drm_mm_init(&mgr->vm_addr_space_mm, page_offset, size);  in drm_vma_offset_manager_init()
94  * drm_vma_offset_manager_destroy() - Destroy offset manager
106 	drm_mm_takedown(&mgr->vm_addr_space_mm);  in drm_vma_offset_manager_destroy()
111  * drm_vma_offset_lookup_locked() - Find node in offset space
113  * @start: Start address for object (page-based)
114  * @pages: Size of object (page-based)
148 	iter = mgr->vm_addr_space_mm.interval_tree.rb_root.rb_node;  in drm_vma_offset_lookup_locked()
153 		offset = node->start;  in drm_vma_offset_lookup_locked()
155 			iter = iter->rb_right;  in drm_vma_offset_lookup_locked()
160 			iter = iter->rb_left;  in drm_vma_offset_lookup_locked()
166 		offset = best->start + best->size;  in drm_vma_offset_lookup_locked()
179  * drm_vma_offset_add() - Add offset node to manager
182  * @pages: Allocation size visible to user-space (in number of pages)
184  * Add a node to the offset-manager. If the node was already added, this does
195  * that you want to map. It only limits the size that user-space can map into
206 	write_lock(&mgr->vm_lock);  in drm_vma_offset_add()
208 	if (!drm_mm_node_allocated(&node->vm_node))  in drm_vma_offset_add()
209 		ret = drm_mm_insert_node(&mgr->vm_addr_space_mm,  in drm_vma_offset_add()
210 					 &node->vm_node, pages);  in drm_vma_offset_add()
212 	write_unlock(&mgr->vm_lock);  in drm_vma_offset_add()
219  * drm_vma_offset_remove() - Remove offset node from manager
232 	write_lock(&mgr->vm_lock);  in drm_vma_offset_remove()
234 	if (drm_mm_node_allocated(&node->vm_node)) {  in drm_vma_offset_remove()
235 		drm_mm_remove_node(&node->vm_node);  in drm_vma_offset_remove()
236 		memset(&node->vm_node, 0, sizeof(node->vm_node));  in drm_vma_offset_remove()
239 	write_unlock(&mgr->vm_lock);  in drm_vma_offset_remove()
244  * drm_vma_node_allow - Add open-file to list of allowed users
248  * Add @tag to the list of allowed open-files for this node. If @tag is
249  * already on this list, the ref-count is incremented.
251  * The list of allowed-users is preserved across drm_vma_offset_add() and
253  * not added to any offset-manager.
255  * You must remove all open-files the same number of times as you added them
261  * 0 on success, negative error code on internal failure (out-of-mem)
271 	 * unlikely that an open-file is added twice to a single node so we  in drm_vma_node_allow()
276 	write_lock(&node->vm_lock);  in drm_vma_node_allow()
278 	iter = &node->vm_files.rb_node;  in drm_vma_node_allow()
284 		if (tag == entry->vm_tag) {  in drm_vma_node_allow()
285 			entry->vm_count++;  in drm_vma_node_allow()
287 		} else if (tag > entry->vm_tag) {  in drm_vma_node_allow()
288 			iter = &(*iter)->rb_right;  in drm_vma_node_allow()
290 			iter = &(*iter)->rb_left;  in drm_vma_node_allow()
295 		ret = -ENOMEM;  in drm_vma_node_allow()
299 	new->vm_tag = tag;  in drm_vma_node_allow()
300 	new->vm_count = 1;  in drm_vma_node_allow()
301 	rb_link_node(&new->vm_rb, parent, iter);  in drm_vma_node_allow()
302 	rb_insert_color(&new->vm_rb, &node->vm_files);  in drm_vma_node_allow()
306 	write_unlock(&node->vm_lock);  in drm_vma_node_allow()
313  * drm_vma_node_revoke - Remove open-file from list of allowed users
317  * Decrement the ref-count of @tag in the list of allowed open-files on @node.
318  * If the ref-count drops to zero, remove @tag from the list. You must call
331 	write_lock(&node->vm_lock);  in drm_vma_node_revoke()
333 	iter = node->vm_files.rb_node;  in drm_vma_node_revoke()
336 		if (tag == entry->vm_tag) {  in drm_vma_node_revoke()
337 			if (!--entry->vm_count) {  in drm_vma_node_revoke()
338 				rb_erase(&entry->vm_rb, &node->vm_files);  in drm_vma_node_revoke()
342 		} else if (tag > entry->vm_tag) {  in drm_vma_node_revoke()
343 			iter = iter->rb_right;  in drm_vma_node_revoke()
345 			iter = iter->rb_left;  in drm_vma_node_revoke()
349 	write_unlock(&node->vm_lock);  in drm_vma_node_revoke()
354  * drm_vma_node_is_allowed - Check whether an open-file is granted access
359  * open-files (see drm_vma_node_allow()).
372 	read_lock(&node->vm_lock);  in drm_vma_node_is_allowed()
374 	iter = node->vm_files.rb_node;  in drm_vma_node_is_allowed()
377 		if (tag == entry->vm_tag)  in drm_vma_node_is_allowed()
379 		else if (tag > entry->vm_tag)  in drm_vma_node_is_allowed()
380 			iter = iter->rb_right;  in drm_vma_node_is_allowed()
382 			iter = iter->rb_left;  in drm_vma_node_is_allowed()
385 	read_unlock(&node->vm_lock);  in drm_vma_node_is_allowed()