1 /* 2 * Copyright © 2012 Red Hat 3 * 4 * Permission is hereby granted, free of charge, to any person obtaining a 5 * copy of this software and associated documentation files (the "Software"), 6 * to deal in the Software without restriction, including without limitation 7 * the rights to use, copy, modify, merge, publish, distribute, sublicense, 8 * and/or sell copies of the Software, and to permit persons to whom the 9 * Software is furnished to do so, subject to the following conditions: 10 * 11 * The above copyright notice and this permission notice (including the next 12 * paragraph) shall be included in all copies or substantial portions of the 13 * Software. 14 * 15 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR 16 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, 17 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL 18 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER 19 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING 20 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS 21 * IN THE SOFTWARE. 22 * 23 * Authors: 24 * Dave Airlie <airlied@redhat.com> 25 * Rob Clark <rob.clark@linaro.org> 26 * 27 */ 28 29 #include <linux/export.h> 30 #include <linux/dma-buf.h> 31 #include <drm/drmP.h> 32 33 /* 34 * DMA-BUF/GEM Object references and lifetime overview: 35 * 36 * On the export the dma_buf holds a reference to the exporting GEM 37 * object. It takes this reference in handle_to_fd_ioctl, when it 38 * first calls .prime_export and stores the exporting GEM object in 39 * the dma_buf priv. This reference is released when the dma_buf 40 * object goes away in the driver .release function. 41 * 42 * On the import the importing GEM object holds a reference to the 43 * dma_buf (which in turn holds a ref to the exporting GEM object). 44 * It takes that reference in the fd_to_handle ioctl. 45 * It calls dma_buf_get, creates an attachment to it and stores the 46 * attachment in the GEM object. When this attachment is destroyed 47 * when the imported object is destroyed, we remove the attachment 48 * and drop the reference to the dma_buf. 49 * 50 * Thus the chain of references always flows in one direction 51 * (avoiding loops): importing_gem -> dmabuf -> exporting_gem 52 * 53 * Self-importing: if userspace is using PRIME as a replacement for flink 54 * then it will get a fd->handle request for a GEM object that it created. 55 * Drivers should detect this situation and return back the gem object 56 * from the dma-buf private. 57 */ 58 59 struct drm_prime_member { 60 struct list_head entry; 61 struct dma_buf *dma_buf; 62 uint32_t handle; 63 }; 64 65 int drm_gem_prime_handle_to_fd(struct drm_device *dev, 66 struct drm_file *file_priv, uint32_t handle, uint32_t flags, 67 int *prime_fd) 68 { 69 struct drm_gem_object *obj; 70 void *buf; 71 int ret; 72 73 obj = drm_gem_object_lookup(dev, file_priv, handle); 74 if (!obj) 75 return -ENOENT; 76 77 mutex_lock(&file_priv->prime.lock); 78 /* re-export the original imported object */ 79 if (obj->import_attach) { 80 get_dma_buf(obj->import_attach->dmabuf); 81 *prime_fd = dma_buf_fd(obj->import_attach->dmabuf, flags); 82 drm_gem_object_unreference_unlocked(obj); 83 mutex_unlock(&file_priv->prime.lock); 84 return 0; 85 } 86 87 if (obj->export_dma_buf) { 88 get_dma_buf(obj->export_dma_buf); 89 *prime_fd = dma_buf_fd(obj->export_dma_buf, flags); 90 drm_gem_object_unreference_unlocked(obj); 91 } else { 92 buf = dev->driver->gem_prime_export(dev, obj, flags); 93 if (IS_ERR(buf)) { 94 /* normally the created dma-buf takes ownership of the ref, 95 * but if that fails then drop the ref 96 */ 97 drm_gem_object_unreference_unlocked(obj); 98 mutex_unlock(&file_priv->prime.lock); 99 return PTR_ERR(buf); 100 } 101 obj->export_dma_buf = buf; 102 *prime_fd = dma_buf_fd(buf, flags); 103 } 104 /* if we've exported this buffer the cheat and add it to the import list 105 * so we get the correct handle back 106 */ 107 ret = drm_prime_add_imported_buf_handle(&file_priv->prime, 108 obj->export_dma_buf, handle); 109 if (ret) { 110 drm_gem_object_unreference_unlocked(obj); 111 mutex_unlock(&file_priv->prime.lock); 112 return ret; 113 } 114 115 mutex_unlock(&file_priv->prime.lock); 116 return 0; 117 } 118 EXPORT_SYMBOL(drm_gem_prime_handle_to_fd); 119 120 int drm_gem_prime_fd_to_handle(struct drm_device *dev, 121 struct drm_file *file_priv, int prime_fd, uint32_t *handle) 122 { 123 struct dma_buf *dma_buf; 124 struct drm_gem_object *obj; 125 int ret; 126 127 dma_buf = dma_buf_get(prime_fd); 128 if (IS_ERR(dma_buf)) 129 return PTR_ERR(dma_buf); 130 131 mutex_lock(&file_priv->prime.lock); 132 133 ret = drm_prime_lookup_imported_buf_handle(&file_priv->prime, 134 dma_buf, handle); 135 if (!ret) { 136 ret = 0; 137 goto out_put; 138 } 139 140 /* never seen this one, need to import */ 141 obj = dev->driver->gem_prime_import(dev, dma_buf); 142 if (IS_ERR(obj)) { 143 ret = PTR_ERR(obj); 144 goto out_put; 145 } 146 147 ret = drm_gem_handle_create(file_priv, obj, handle); 148 drm_gem_object_unreference_unlocked(obj); 149 if (ret) 150 goto out_put; 151 152 ret = drm_prime_add_imported_buf_handle(&file_priv->prime, 153 dma_buf, *handle); 154 if (ret) 155 goto fail; 156 157 mutex_unlock(&file_priv->prime.lock); 158 return 0; 159 160 fail: 161 /* hmm, if driver attached, we are relying on the free-object path 162 * to detach.. which seems ok.. 163 */ 164 drm_gem_object_handle_unreference_unlocked(obj); 165 out_put: 166 dma_buf_put(dma_buf); 167 mutex_unlock(&file_priv->prime.lock); 168 return ret; 169 } 170 EXPORT_SYMBOL(drm_gem_prime_fd_to_handle); 171 172 int drm_prime_handle_to_fd_ioctl(struct drm_device *dev, void *data, 173 struct drm_file *file_priv) 174 { 175 struct drm_prime_handle *args = data; 176 uint32_t flags; 177 178 if (!drm_core_check_feature(dev, DRIVER_PRIME)) 179 return -EINVAL; 180 181 if (!dev->driver->prime_handle_to_fd) 182 return -ENOSYS; 183 184 /* check flags are valid */ 185 if (args->flags & ~DRM_CLOEXEC) 186 return -EINVAL; 187 188 /* we only want to pass DRM_CLOEXEC which is == O_CLOEXEC */ 189 flags = args->flags & DRM_CLOEXEC; 190 191 return dev->driver->prime_handle_to_fd(dev, file_priv, 192 args->handle, flags, &args->fd); 193 } 194 195 int drm_prime_fd_to_handle_ioctl(struct drm_device *dev, void *data, 196 struct drm_file *file_priv) 197 { 198 struct drm_prime_handle *args = data; 199 200 if (!drm_core_check_feature(dev, DRIVER_PRIME)) 201 return -EINVAL; 202 203 if (!dev->driver->prime_fd_to_handle) 204 return -ENOSYS; 205 206 return dev->driver->prime_fd_to_handle(dev, file_priv, 207 args->fd, &args->handle); 208 } 209 210 /* 211 * drm_prime_pages_to_sg 212 * 213 * this helper creates an sg table object from a set of pages 214 * the driver is responsible for mapping the pages into the 215 * importers address space 216 */ 217 struct sg_table *drm_prime_pages_to_sg(struct page **pages, int nr_pages) 218 { 219 struct sg_table *sg = NULL; 220 struct scatterlist *iter; 221 int i; 222 int ret; 223 224 sg = kmalloc(sizeof(struct sg_table), GFP_KERNEL); 225 if (!sg) 226 goto out; 227 228 ret = sg_alloc_table(sg, nr_pages, GFP_KERNEL); 229 if (ret) 230 goto out; 231 232 for_each_sg(sg->sgl, iter, nr_pages, i) 233 sg_set_page(iter, pages[i], PAGE_SIZE, 0); 234 235 return sg; 236 out: 237 kfree(sg); 238 return NULL; 239 } 240 EXPORT_SYMBOL(drm_prime_pages_to_sg); 241 242 /* export an sg table into an array of pages and addresses 243 this is currently required by the TTM driver in order to do correct fault 244 handling */ 245 int drm_prime_sg_to_page_addr_arrays(struct sg_table *sgt, struct page **pages, 246 dma_addr_t *addrs, int max_pages) 247 { 248 unsigned count; 249 struct scatterlist *sg; 250 struct page *page; 251 u32 len, offset; 252 int pg_index; 253 dma_addr_t addr; 254 255 pg_index = 0; 256 for_each_sg(sgt->sgl, sg, sgt->nents, count) { 257 len = sg->length; 258 offset = sg->offset; 259 page = sg_page(sg); 260 addr = sg_dma_address(sg); 261 262 while (len > 0) { 263 if (WARN_ON(pg_index >= max_pages)) 264 return -1; 265 pages[pg_index] = page; 266 if (addrs) 267 addrs[pg_index] = addr; 268 269 page++; 270 addr += PAGE_SIZE; 271 len -= PAGE_SIZE; 272 pg_index++; 273 } 274 } 275 return 0; 276 } 277 EXPORT_SYMBOL(drm_prime_sg_to_page_addr_arrays); 278 /* helper function to cleanup a GEM/prime object */ 279 void drm_prime_gem_destroy(struct drm_gem_object *obj, struct sg_table *sg) 280 { 281 struct dma_buf_attachment *attach; 282 struct dma_buf *dma_buf; 283 attach = obj->import_attach; 284 if (sg) 285 dma_buf_unmap_attachment(attach, sg, DMA_BIDIRECTIONAL); 286 dma_buf = attach->dmabuf; 287 dma_buf_detach(attach->dmabuf, attach); 288 /* remove the reference */ 289 dma_buf_put(dma_buf); 290 } 291 EXPORT_SYMBOL(drm_prime_gem_destroy); 292 293 void drm_prime_init_file_private(struct drm_prime_file_private *prime_fpriv) 294 { 295 INIT_LIST_HEAD(&prime_fpriv->head); 296 mutex_init(&prime_fpriv->lock); 297 } 298 EXPORT_SYMBOL(drm_prime_init_file_private); 299 300 void drm_prime_destroy_file_private(struct drm_prime_file_private *prime_fpriv) 301 { 302 struct drm_prime_member *member, *safe; 303 list_for_each_entry_safe(member, safe, &prime_fpriv->head, entry) { 304 list_del(&member->entry); 305 kfree(member); 306 } 307 } 308 EXPORT_SYMBOL(drm_prime_destroy_file_private); 309 310 int drm_prime_add_imported_buf_handle(struct drm_prime_file_private *prime_fpriv, struct dma_buf *dma_buf, uint32_t handle) 311 { 312 struct drm_prime_member *member; 313 314 member = kmalloc(sizeof(*member), GFP_KERNEL); 315 if (!member) 316 return -ENOMEM; 317 318 member->dma_buf = dma_buf; 319 member->handle = handle; 320 list_add(&member->entry, &prime_fpriv->head); 321 return 0; 322 } 323 EXPORT_SYMBOL(drm_prime_add_imported_buf_handle); 324 325 int drm_prime_lookup_imported_buf_handle(struct drm_prime_file_private *prime_fpriv, struct dma_buf *dma_buf, uint32_t *handle) 326 { 327 struct drm_prime_member *member; 328 329 list_for_each_entry(member, &prime_fpriv->head, entry) { 330 if (member->dma_buf == dma_buf) { 331 *handle = member->handle; 332 return 0; 333 } 334 } 335 return -ENOENT; 336 } 337 EXPORT_SYMBOL(drm_prime_lookup_imported_buf_handle); 338 339 void drm_prime_remove_imported_buf_handle(struct drm_prime_file_private *prime_fpriv, struct dma_buf *dma_buf) 340 { 341 struct drm_prime_member *member, *safe; 342 343 mutex_lock(&prime_fpriv->lock); 344 list_for_each_entry_safe(member, safe, &prime_fpriv->head, entry) { 345 if (member->dma_buf == dma_buf) { 346 list_del(&member->entry); 347 kfree(member); 348 } 349 } 350 mutex_unlock(&prime_fpriv->lock); 351 } 352 EXPORT_SYMBOL(drm_prime_remove_imported_buf_handle); 353