drivers/gpu/drm/ttm/ttm_bo_vm.c

   1 /**************************************************************************
   2  *
   3  * Copyright (c) 2006-2009 VMware, Inc., Palo Alto, CA., USA
   4  * All Rights Reserved.
   5  *
   6  * Permission is hereby granted, free of charge, to any person obtaining a
   7  * copy of this software and associated documentation files (the
   8  * "Software"), to deal in the Software without restriction, including
   9  * without limitation the rights to use, copy, modify, merge, publish,
  10  * distribute, sub license, and/or sell copies of the Software, and to
  11  * permit persons to whom the Software is furnished to do so, subject to
  12  * the following conditions:
  13  *
  14  * The above copyright notice and this permission notice (including the
  15  * next paragraph) shall be included in all copies or substantial portions
  16  * of the Software.
  17  *
  18  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  19  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  20  * FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL
  21  * THE COPYRIGHT HOLDERS, AUTHORS AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM,
  22  * DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
  23  * OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
  24  * USE OR OTHER DEALINGS IN THE SOFTWARE.
  25  *
  26  **************************************************************************/
  27 /*
  28  * Authors: Thomas Hellstrom <thellstrom-at-vmware-dot-com>
  29  */
  30
  31 #include <ttm/ttm_module.h>
  32 #include <ttm/ttm_bo_driver.h>
  33 #include <ttm/ttm_placement.h>
  34 #include <linux/mm.h>
  35 #include <linux/rbtree.h>
  36 #include <linux/module.h>
  37 #include <linux/uaccess.h>
  38
  39 #define TTM_BO_VM_NUM_PREFAULT 16
  40
  41 static struct ttm_buffer_object *ttm_bo_vm_lookup_rb(struct ttm_bo_device *bdev,
  42                                                      unsigned long page_start,
  43                                                      unsigned long num_pages)
  44 {
  45         struct rb_node *cur = bdev->addr_space_rb.rb_node;
  46         unsigned long cur_offset;
  47         struct ttm_buffer_object *bo;
  48         struct ttm_buffer_object *best_bo = NULL;
  49
  50         while (likely(cur != NULL)) {
  51                 bo = rb_entry(cur, struct ttm_buffer_object, vm_rb);
  52                 cur_offset = bo->vm_node->start;
  53                 if (page_start >= cur_offset) {
  54                         cur = cur->rb_right;
  55                         best_bo = bo;
  56                         if (page_start == cur_offset)
  57                                 break;
  58                 } else
  59                         cur = cur->rb_left;
  60         }
  61
  62         if (unlikely(best_bo == NULL))
  63                 return NULL;
  64
  65         if (unlikely((best_bo->vm_node->start + best_bo->num_pages) <
  66                      (page_start + num_pages)))
  67                 return NULL;
  68
  69         return best_bo;
  70 }
  71
  72 static int ttm_bo_vm_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
  73 {
  74         struct ttm_buffer_object *bo = (struct ttm_buffer_object *)
  75             vma->vm_private_data;
  76         struct ttm_bo_device *bdev = bo->bdev;
  77         unsigned long page_offset;
  78         unsigned long page_last;
  79         unsigned long pfn;
  80         struct ttm_tt *ttm = NULL;
  81         struct page *page;
  82         int ret;
  83         int i;
  84         unsigned long address = (unsigned long)vmf->virtual_address;
  85         int retval = VM_FAULT_NOPAGE;
  86
  87         /*
  88          * Work around locking order reversal in fault / nopfn
  89          * between mmap_sem and bo_reserve: Perform a trylock operation
  90          * for reserve, and if it fails, retry the fault after scheduling.
  91          */
  92
  93         ret = ttm_bo_reserve(bo, true, true, false, 0);
  94         if (unlikely(ret != 0)) {
  95                 if (ret == -EBUSY)
  96                         set_need_resched();
  97                 return VM_FAULT_NOPAGE;
  98         }
  99
 100         if (bdev->driver->fault_reserve_notify) {
 101                 ret = bdev->driver->fault_reserve_notify(bo);
 102                 switch (ret) {
 103                 case 0:
 104                         break;
 105                 case -EBUSY:
 106                         set_need_resched();
 107                 case -ERESTARTSYS:
 108                         retval = VM_FAULT_NOPAGE;
 109                         goto out_unlock;
 110                 default:
 111                         retval = VM_FAULT_SIGBUS;
 112                         goto out_unlock;
 113                 }
 114         }
 115
 116         /*
 117          * Wait for buffer data in transit, due to a pipelined
 118          * move.
 119          */
 120
 121         spin_lock(&bo->lock);
 122         if (test_bit(TTM_BO_PRIV_FLAG_MOVING, &bo->priv_flags)) {
 123                 ret = ttm_bo_wait(bo, false, true, false);
 124                 spin_unlock(&bo->lock);
 125                 if (unlikely(ret != 0)) {
 126                         retval = (ret != -ERESTARTSYS) ?
 127                             VM_FAULT_SIGBUS : VM_FAULT_NOPAGE;
 128                         goto out_unlock;
 129                 }
 130         } else
 131                 spin_unlock(&bo->lock);
 132
 133
 134         ret = ttm_mem_io_reserve(bdev, &bo->mem);
 135         if (ret) {
 136                 retval = VM_FAULT_SIGBUS;
 137                 goto out_unlock;
 138         }
 139
 140         page_offset = ((address - vma->vm_start) >> PAGE_SHIFT) +
 141             bo->vm_node->start - vma->vm_pgoff;
 142         page_last = ((vma->vm_end - vma->vm_start) >> PAGE_SHIFT) +
 143             bo->vm_node->start - vma->vm_pgoff;
 144
 145         if (unlikely(page_offset >= bo->num_pages)) {
 146                 retval = VM_FAULT_SIGBUS;
 147                 goto out_unlock;
 148         }
 149
 150         /*
 151          * Strictly, we're not allowed to modify vma->vm_page_prot here,
 152          * since the mmap_sem is only held in read mode. However, we
 153          * modify only the caching bits of vma->vm_page_prot and
 154          * consider those bits protected by
 155          * the bo->mutex, as we should be the only writers.
 156          * There shouldn't really be any readers of these bits except
 157          * within vm_insert_mixed()? fork?
 158          *
 159          * TODO: Add a list of vmas to the bo, and change the
 160          * vma->vm_page_prot when the object changes caching policy, with
 161          * the correct locks held.
 162          */
 163         if (bo->mem.bus.is_iomem) {
 164                 vma->vm_page_prot = ttm_io_prot(bo->mem.placement,
 165                                                 vma->vm_page_prot);
 166         } else {
 167                 ttm = bo->ttm;
 168                 vma->vm_page_prot = (bo->mem.placement & TTM_PL_FLAG_CACHED) ?
 169                     vm_get_page_prot(vma->vm_flags) :
 170                     ttm_io_prot(bo->mem.placement, vma->vm_page_prot);
 171         }
 172
 173         /*
 174          * Speculatively prefault a number of pages. Only error on
 175          * first page.
 176          */
 177
 178         for (i = 0; i < TTM_BO_VM_NUM_PREFAULT; ++i) {
 179                 if (bo->mem.bus.is_iomem)
 180                         pfn = ((bo->mem.bus.base + bo->mem.bus.offset) >> PAGE_SHIFT) + page_offset;
 181                 else {
 182                         page = ttm_tt_get_page(ttm, page_offset);
 183                         if (unlikely(!page && i == 0)) {
 184                                 retval = VM_FAULT_OOM;
 185                                 goto out_unlock;
 186                         } else if (unlikely(!page)) {
 187                                 break;
 188                         }
 189                         pfn = page_to_pfn(page);
 190                 }
 191
 192                 ret = vm_insert_mixed(vma, address, pfn);
 193                 /*
 194                  * Somebody beat us to this PTE or prefaulting to
 195                  * an already populated PTE, or prefaulting error.
 196                  */
 197
 198                 if (unlikely((ret == -EBUSY) || (ret != 0 && i > 0)))
 199                         break;
 200                 else if (unlikely(ret != 0)) {
 201                         retval =
 202                             (ret == -ENOMEM) ? VM_FAULT_OOM : VM_FAULT_SIGBUS;
 203                         goto out_unlock;
 204                 }
 205
 206                 address += PAGE_SIZE;
 207                 if (unlikely(++page_offset >= page_last))
 208                         break;
 209         }
 210
 211 out_unlock:
 212         ttm_bo_unreserve(bo);
 213         return retval;
 214 }
 215
 216 static void ttm_bo_vm_open(struct vm_area_struct *vma)
 217 {
 218         struct ttm_buffer_object *bo =
 219             (struct ttm_buffer_object *)vma->vm_private_data;
 220
 221         (void)ttm_bo_reference(bo);
 222 }
 223
 224 static void ttm_bo_vm_close(struct vm_area_struct *vma)
 225 {
 226         struct ttm_buffer_object *bo = (struct ttm_buffer_object *)vma->vm_private_data;
 227
 228         ttm_bo_unref(&bo);
 229         vma->vm_private_data = NULL;
 230 }
 231
 232 static const struct vm_operations_struct ttm_bo_vm_ops = {
 233         .fault = ttm_bo_vm_fault,
 234         .open = ttm_bo_vm_open,
 235         .close = ttm_bo_vm_close
 236 };
 237
 238 int ttm_bo_mmap(struct file *filp, struct vm_area_struct *vma,
 239                 struct ttm_bo_device *bdev)
 240 {
 241         struct ttm_bo_driver *driver;
 242         struct ttm_buffer_object *bo;
 243         int ret;
 244
 245         read_lock(&bdev->vm_lock);
 246         bo = ttm_bo_vm_lookup_rb(bdev, vma->vm_pgoff,
 247                                  (vma->vm_end - vma->vm_start) >> PAGE_SHIFT);
 248         if (likely(bo != NULL))
 249                 ttm_bo_reference(bo);
 250         read_unlock(&bdev->vm_lock);
 251
 252         if (unlikely(bo == NULL)) {
 253                 printk(KERN_ERR TTM_PFX
 254                        "Could not find buffer object to map.\n");
 255                 return -EINVAL;
 256         }
 257
 258         driver = bo->bdev->driver;
 259         if (unlikely(!driver->verify_access)) {
 260                 ret = -EPERM;
 261                 goto out_unref;
 262         }
 263         ret = driver->verify_access(bo, filp);
 264         if (unlikely(ret != 0))
 265                 goto out_unref;
 266
 267         vma->vm_ops = &ttm_bo_vm_ops;
 268
 269         /*
 270          * Note: We're transferring the bo reference to
 271          * vma->vm_private_data here.
 272          */
 273
 274         vma->vm_private_data = bo;
 275         vma->vm_flags |= VM_RESERVED | VM_IO | VM_MIXEDMAP | VM_DONTEXPAND;
 276         return 0;
 277 out_unref:
 278         ttm_bo_unref(&bo);
 279         return ret;
 280 }
 281 EXPORT_SYMBOL(ttm_bo_mmap);
 282
 283 int ttm_fbdev_mmap(struct vm_area_struct *vma, struct ttm_buffer_object *bo)
 284 {
 285         if (vma->vm_pgoff != 0)
 286                 return -EACCES;
 287
 288         vma->vm_ops = &ttm_bo_vm_ops;
 289         vma->vm_private_data = ttm_bo_reference(bo);
 290         vma->vm_flags |= VM_RESERVED | VM_IO | VM_MIXEDMAP | VM_DONTEXPAND;
 291         return 0;
 292 }
 293 EXPORT_SYMBOL(ttm_fbdev_mmap);
 294
 295
 296 ssize_t ttm_bo_io(struct ttm_bo_device *bdev, struct file *filp,
 297                   const char __user *wbuf, char __user *rbuf, size_t count,
 298                   loff_t *f_pos, bool write)
 299 {
 300         struct ttm_buffer_object *bo;
 301         struct ttm_bo_driver *driver;
 302         struct ttm_bo_kmap_obj map;
 303         unsigned long dev_offset = (*f_pos >> PAGE_SHIFT);
 304         unsigned long kmap_offset;
 305         unsigned long kmap_end;
 306         unsigned long kmap_num;
 307         size_t io_size;
 308         unsigned int page_offset;
 309         char *virtual;
 310         int ret;
 311         bool no_wait = false;
 312         bool dummy;
 313
 314         read_lock(&bdev->vm_lock);
 315         bo = ttm_bo_vm_lookup_rb(bdev, dev_offset, 1);
 316         if (likely(bo != NULL))
 317                 ttm_bo_reference(bo);
 318         read_unlock(&bdev->vm_lock);
 319
 320         if (unlikely(bo == NULL))
 321                 return -EFAULT;
 322
 323         driver = bo->bdev->driver;
 324         if (unlikely(!driver->verify_access)) {
 325                 ret = -EPERM;
 326                 goto out_unref;
 327         }
 328
 329         ret = driver->verify_access(bo, filp);
 330         if (unlikely(ret != 0))
 331                 goto out_unref;
 332
 333         kmap_offset = dev_offset - bo->vm_node->start;
 334         if (unlikely(kmap_offset >= bo->num_pages)) {
 335                 ret = -EFBIG;
 336                 goto out_unref;
 337         }
 338
 339         page_offset = *f_pos & ~PAGE_MASK;
 340         io_size = bo->num_pages - kmap_offset;
 341         io_size = (io_size << PAGE_SHIFT) - page_offset;
 342         if (count < io_size)
 343                 io_size = count;
 344
 345         kmap_end = (*f_pos + count - 1) >> PAGE_SHIFT;
 346         kmap_num = kmap_end - kmap_offset + 1;
 347
 348         ret = ttm_bo_reserve(bo, true, no_wait, false, 0);
 349
 350         switch (ret) {
 351         case 0:
 352                 break;
 353         case -EBUSY:
 354                 ret = -EAGAIN;
 355                 goto out_unref;
 356         default:
 357                 goto out_unref;
 358         }
 359
 360         ret = ttm_bo_kmap(bo, kmap_offset, kmap_num, &map);
 361         if (unlikely(ret != 0)) {
 362                 ttm_bo_unreserve(bo);
 363                 goto out_unref;
 364         }
 365
 366         virtual = ttm_kmap_obj_virtual(&map, &dummy);
 367         virtual += page_offset;
 368
 369         if (write)
 370                 ret = copy_from_user(virtual, wbuf, io_size);
 371         else
 372                 ret = copy_to_user(rbuf, virtual, io_size);
 373
 374         ttm_bo_kunmap(&map);
 375         ttm_bo_unreserve(bo);
 376         ttm_bo_unref(&bo);
 377
 378         if (unlikely(ret != 0))
 379                 return -EFBIG;
 380
 381         *f_pos += io_size;
 382
 383         return io_size;
 384 out_unref:
 385         ttm_bo_unref(&bo);
 386         return ret;
 387 }
 388
 389 ssize_t ttm_bo_fbdev_io(struct ttm_buffer_object *bo, const char __user *wbuf,
 390                         char __user *rbuf, size_t count, loff_t *f_pos,
 391                         bool write)
 392 {
 393         struct ttm_bo_kmap_obj map;
 394         unsigned long kmap_offset;
 395         unsigned long kmap_end;
 396         unsigned long kmap_num;
 397         size_t io_size;
 398         unsigned int page_offset;
 399         char *virtual;
 400         int ret;
 401         bool no_wait = false;
 402         bool dummy;
 403
 404         kmap_offset = (*f_pos >> PAGE_SHIFT);
 405         if (unlikely(kmap_offset >= bo->num_pages))
 406                 return -EFBIG;
 407
 408         page_offset = *f_pos & ~PAGE_MASK;
 409         io_size = bo->num_pages - kmap_offset;
 410         io_size = (io_size << PAGE_SHIFT) - page_offset;
 411         if (count < io_size)
 412                 io_size = count;
 413
 414         kmap_end = (*f_pos + count - 1) >> PAGE_SHIFT;
 415         kmap_num = kmap_end - kmap_offset + 1;
 416
 417         ret = ttm_bo_reserve(bo, true, no_wait, false, 0);
 418
 419         switch (ret) {
 420         case 0:
 421                 break;
 422         case -EBUSY:
 423                 return -EAGAIN;
 424         default:
 425                 return ret;
 426         }
 427
 428         ret = ttm_bo_kmap(bo, kmap_offset, kmap_num, &map);
 429         if (unlikely(ret != 0)) {
 430                 ttm_bo_unreserve(bo);
 431                 return ret;
 432         }
 433
 434         virtual = ttm_kmap_obj_virtual(&map, &dummy);
 435         virtual += page_offset;
 436
 437         if (write)
 438                 ret = copy_from_user(virtual, wbuf, io_size);
 439         else
 440                 ret = copy_to_user(rbuf, virtual, io_size);
 441
 442         ttm_bo_kunmap(&map);
 443         ttm_bo_unreserve(bo);
 444         ttm_bo_unref(&bo);
 445
 446         if (unlikely(ret != 0))
 447                 return ret;
 448
 449         *f_pos += io_size;
 450
 451         return io_size;
 452 }