/* * Copyright (c) 2006-2009 VMware, Inc., Palo Alto, CA., USA * Copyright (c) 2012 David Airlie * Copyright (c) 2013 David Herrmann * * Permission is hereby granted, free of charge, to any person obtaining a * copy of this software and associated documentation files (the "Software"), * to deal in the Software without restriction, including without limitation * the rights to use, copy, modify, merge, publish, distribute, sublicense, * and/or sell copies of the Software, and to permit persons to whom the * Software is furnished to do so, subject to the following conditions: * * The above copyright notice and this permission notice shall be included in * all copies or substantial portions of the Software. * * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL * THE COPYRIGHT HOLDER(S) OR AUTHOR(S) BE LIABLE FOR ANY CLAIM, DAMAGES OR * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR * OTHER DEALINGS IN THE SOFTWARE. */ #include #include #include #include #include #include #include #include #include /** * DOC: vma offset manager * * The vma-manager is responsible to map arbitrary driver-dependent memory * regions into the linear user address-space. It provides offsets to the * caller which can then be used on the address_space of the drm-device. It * takes care to not overlap regions, size them appropriately and to not * confuse mm-core by inconsistent fake vm_pgoff fields. * Drivers shouldn't use this for object placement in VMEM. This manager should * only be used to manage mappings into linear user-space VMs. * * We use drm_mm as backend to manage object allocations. But it is highly * optimized for alloc/free calls, not lookups. Hence, we use an rb-tree to * speed up offset lookups. * * You must not use multiple offset managers on a single address_space. * Otherwise, mm-core will be unable to tear down memory mappings as the VM will * no longer be linear. Please use VM_NONLINEAR in that case and implement your * own offset managers. * * This offset manager works on page-based addresses. That is, every argument * and return code (with the exception of drm_vma_node_offset_addr()) is given * in number of pages, not number of bytes. That means, object sizes and offsets * must always be page-aligned (as usual). * If you want to get a valid byte-based user-space address for a given offset, * please see drm_vma_node_offset_addr(). */ /** * drm_vma_offset_manager_init - Initialize new offset-manager * @mgr: Manager object * @page_offset: Offset of available memory area (page-based) * @size: Size of available address space range (page-based) * * Initialize a new offset-manager. The offset and area size available for the * manager are given as @page_offset and @size. Both are interpreted as * page-numbers, not bytes. * * Adding/removing nodes from the manager is locked internally and protected * against concurrent access. However, node allocation and destruction is left * for the caller. While calling into the vma-manager, a given node must * always be guaranteed to be referenced. */ void drm_vma_offset_manager_init(struct drm_vma_offset_manager *mgr, unsigned long page_offset, unsigned long size) { lockinit(&mgr->vm_lock, "drmvml", 0, LK_CANRECURSE); mgr->vm_addr_space_rb = RB_ROOT; drm_mm_init(&mgr->vm_addr_space_mm, page_offset, size); } EXPORT_SYMBOL(drm_vma_offset_manager_init); /** * drm_vma_offset_manager_destroy() - Destroy offset manager * @mgr: Manager object * * Destroy an object manager which was previously created via * drm_vma_offset_manager_init(). The caller must remove all allocated nodes * before destroying the manager. Otherwise, drm_mm will refuse to free the * requested resources. * * The manager must not be accessed after this function is called. */ void drm_vma_offset_manager_destroy(struct drm_vma_offset_manager *mgr) { /* take the lock to protect against buggy drivers */ lockmgr(&mgr->vm_lock, LK_EXCLUSIVE); drm_mm_takedown(&mgr->vm_addr_space_mm); lockmgr(&mgr->vm_lock, LK_RELEASE); } EXPORT_SYMBOL(drm_vma_offset_manager_destroy); /** * drm_vma_offset_lookup() - Find node in offset space * @mgr: Manager object * @start: Start address for object (page-based) * @pages: Size of object (page-based) * * Find a node given a start address and object size. This returns the _best_ * match for the given node. That is, @start may point somewhere into a valid * region and the given node will be returned, as long as the node spans the * whole requested area (given the size in number of pages as @pages). * * RETURNS: * Returns NULL if no suitable node can be found. Otherwise, the best match * is returned. It's the caller's responsibility to make sure the node doesn't * get destroyed before the caller can access it. */ struct drm_vma_offset_node *drm_vma_offset_lookup(struct drm_vma_offset_manager *mgr, unsigned long start, unsigned long pages) { struct drm_vma_offset_node *node; lockmgr(&mgr->vm_lock, LK_EXCLUSIVE); node = drm_vma_offset_lookup_locked(mgr, start, pages); lockmgr(&mgr->vm_lock, LK_RELEASE); return node; } EXPORT_SYMBOL(drm_vma_offset_lookup); /** * drm_vma_offset_lookup_locked() - Find node in offset space * @mgr: Manager object * @start: Start address for object (page-based) * @pages: Size of object (page-based) * * Same as drm_vma_offset_lookup() but requires the caller to lock offset lookup * manually. See drm_vma_offset_lock_lookup() for an example. * * RETURNS: * Returns NULL if no suitable node can be found. Otherwise, the best match * is returned. */ struct drm_vma_offset_node *drm_vma_offset_lookup_locked(struct drm_vma_offset_manager *mgr, unsigned long start, unsigned long pages) { struct drm_vma_offset_node *node, *best; struct rb_node *iter; unsigned long offset; iter = mgr->vm_addr_space_rb.rb_node; best = NULL; while (likely(iter)) { node = rb_entry(iter, struct drm_vma_offset_node, vm_rb); offset = node->vm_node.start; if (start >= offset) { iter = iter->rb_right; best = node; if (start == offset) break; } else { iter = iter->rb_left; } } /* verify that the node spans the requested area */ if (best) { offset = best->vm_node.start + best->vm_node.size; if (offset < start + pages) best = NULL; } return best; } EXPORT_SYMBOL(drm_vma_offset_lookup_locked); /* internal helper to link @node into the rb-tree */ static void _drm_vma_offset_add_rb(struct drm_vma_offset_manager *mgr, struct drm_vma_offset_node *node) { struct rb_node **iter = &mgr->vm_addr_space_rb.rb_node; struct rb_node *parent = NULL; struct drm_vma_offset_node *iter_node; while (likely(*iter)) { parent = *iter; iter_node = rb_entry(*iter, struct drm_vma_offset_node, vm_rb); if (node->vm_node.start < iter_node->vm_node.start) iter = &(*iter)->rb_left; else if (node->vm_node.start > iter_node->vm_node.start) iter = &(*iter)->rb_right; else BUG(); } rb_link_node(&node->vm_rb, parent, iter); rb_insert_color(&node->vm_rb, &mgr->vm_addr_space_rb); } /** * drm_vma_offset_add() - Add offset node to manager * @mgr: Manager object * @node: Node to be added * @pages: Allocation size visible to user-space (in number of pages) * * Add a node to the offset-manager. If the node was already added, this does * nothing and return 0. @pages is the size of the object given in number of * pages. * After this call succeeds, you can access the offset of the node until it * is removed again. * * If this call fails, it is safe to retry the operation or call * drm_vma_offset_remove(), anyway. However, no cleanup is required in that * case. * * @pages is not required to be the same size as the underlying memory object * that you want to map. It only limits the size that user-space can map into * their address space. * * RETURNS: * 0 on success, negative error code on failure. */ int drm_vma_offset_add(struct drm_vma_offset_manager *mgr, struct drm_vma_offset_node *node, unsigned long pages) { int ret; lockmgr(&mgr->vm_lock, LK_EXCLUSIVE); if (drm_mm_node_allocated(&node->vm_node)) { ret = 0; goto out_unlock; } ret = drm_mm_insert_node(&mgr->vm_addr_space_mm, &node->vm_node, pages, 0, DRM_MM_SEARCH_DEFAULT); if (ret) goto out_unlock; _drm_vma_offset_add_rb(mgr, node); out_unlock: lockmgr(&mgr->vm_lock, LK_RELEASE); return ret; } EXPORT_SYMBOL(drm_vma_offset_add); /** * drm_vma_offset_remove() - Remove offset node from manager * @mgr: Manager object * @node: Node to be removed * * Remove a node from the offset manager. If the node wasn't added before, this * does nothing. After this call returns, the offset and size will be 0 until a * new offset is allocated via drm_vma_offset_add() again. Helper functions like * drm_vma_node_start() and drm_vma_node_offset_addr() will return 0 if no * offset is allocated. */ void drm_vma_offset_remove(struct drm_vma_offset_manager *mgr, struct drm_vma_offset_node *node) { lockmgr(&mgr->vm_lock, LK_EXCLUSIVE); if (drm_mm_node_allocated(&node->vm_node)) { rb_erase(&node->vm_rb, &mgr->vm_addr_space_rb); drm_mm_remove_node(&node->vm_node); memset(&node->vm_node, 0, sizeof(node->vm_node)); } lockmgr(&mgr->vm_lock, LK_RELEASE); } EXPORT_SYMBOL(drm_vma_offset_remove);