1 /* $NetBSD: drm_gem_vm.c,v 1.9 2018/08/27 07:51:06 riastradh Exp $ */ 2 3 /*- 4 * Copyright (c) 2013 The NetBSD Foundation, Inc. 5 * All rights reserved. 6 * 7 * This code is derived from software contributed to The NetBSD Foundation 8 * by Taylor R. Campbell. 9 * 10 * Redistribution and use in source and binary forms, with or without 11 * modification, are permitted provided that the following conditions 12 * are met: 13 * 1. Redistributions of source code must retain the above copyright 14 * notice, this list of conditions and the following disclaimer. 15 * 2. Redistributions in binary form must reproduce the above copyright 16 * notice, this list of conditions and the following disclaimer in the 17 * documentation and/or other materials provided with the distribution. 18 * 19 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 20 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 21 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 22 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 23 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 24 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 25 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 26 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 27 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 28 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 29 * POSSIBILITY OF SUCH DAMAGE. 30 */ 31 32 #include <sys/cdefs.h> 33 __KERNEL_RCSID(0, "$NetBSD: drm_gem_vm.c,v 1.9 2018/08/27 07:51:06 riastradh Exp $"); 34 35 #include <sys/types.h> 36 37 #include <uvm/uvm_extern.h> 38 39 #include <drm/drmP.h> 40 #include <drm/drm_gem.h> 41 #include <drm/drm_legacy.h> 42 #include <drm/drm_vma_manager.h> 43 44 static int drm_gem_mmap_object_locked(struct drm_device *, off_t, size_t, 45 int, struct uvm_object **, voff_t *, struct file *); 46 47 void 48 drm_gem_pager_reference(struct uvm_object *uobj) 49 { 50 struct drm_gem_object *const obj = container_of(uobj, 51 struct drm_gem_object, gemo_uvmobj); 52 53 drm_gem_object_reference(obj); 54 } 55 56 void 57 drm_gem_pager_detach(struct uvm_object *uobj) 58 { 59 struct drm_gem_object *const obj = container_of(uobj, 60 struct drm_gem_object, gemo_uvmobj); 61 62 drm_gem_object_unreference_unlocked(obj); 63 } 64 65 int 66 drm_gem_or_legacy_mmap_object(struct drm_device *dev, off_t byte_offset, 67 size_t nbytes, int prot, struct uvm_object **uobjp, voff_t *uoffsetp, 68 struct file *file) 69 { 70 int ret; 71 72 ret = drm_gem_mmap_object(dev, byte_offset, nbytes, prot, uobjp, 73 uoffsetp, file); 74 if (ret) 75 return ret; 76 if (*uobjp != NULL) 77 return 0; 78 79 return drm_legacy_mmap_object(dev, byte_offset, nbytes, prot, uobjp, 80 uoffsetp, file); 81 } 82 83 int 84 drm_gem_mmap_object(struct drm_device *dev, off_t byte_offset, size_t nbytes, 85 int prot, struct uvm_object **uobjp, voff_t *uoffsetp, struct file *file) 86 { 87 int ret; 88 89 mutex_lock(&dev->struct_mutex); 90 ret = drm_gem_mmap_object_locked(dev, byte_offset, nbytes, prot, 91 uobjp, uoffsetp, file); 92 mutex_unlock(&dev->struct_mutex); 93 94 return ret; 95 } 96 97 static int 98 drm_gem_mmap_object_locked(struct drm_device *dev, off_t byte_offset, 99 size_t nbytes, int prot __unused, struct uvm_object **uobjp, 100 voff_t *uoffsetp, struct file *file) 101 { 102 const unsigned long startpage = (byte_offset >> PAGE_SHIFT); 103 const unsigned long npages = (nbytes >> PAGE_SHIFT); 104 105 KASSERT(mutex_is_locked(&dev->struct_mutex)); 106 KASSERT(drm_core_check_feature(dev, DRIVER_GEM)); 107 KASSERT(dev->driver->gem_uvm_ops != NULL); 108 KASSERT(prot == (prot & (PROT_READ | PROT_WRITE))); 109 KASSERT(0 <= byte_offset); 110 KASSERT(byte_offset == (byte_offset & ~(PAGE_SIZE-1))); 111 KASSERT(nbytes == (npages << PAGE_SHIFT)); 112 113 struct drm_vma_offset_node *const node = 114 drm_vma_offset_exact_lookup(dev->vma_offset_manager, startpage, 115 npages); 116 if (node == NULL) { 117 /* Fall back to vanilla device mappings. */ 118 *uobjp = NULL; 119 *uoffsetp = (voff_t)-1; 120 return 0; 121 } 122 123 if (!drm_vma_node_is_allowed(node, file)) 124 return -EACCES; 125 126 struct drm_gem_object *const obj = container_of(node, 127 struct drm_gem_object, vma_node); 128 KASSERT(obj->dev == dev); 129 130 /* Success! */ 131 drm_gem_object_reference(obj); 132 *uobjp = &obj->gemo_uvmobj; 133 *uoffsetp = 0; 134 return 0; 135 } 136