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 bus_base;
  78         unsigned long bus_offset;
  79         unsigned long bus_size;
  80         unsigned long page_offset;
  81         unsigned long page_last;
  82         unsigned long pfn;
  83         struct ttm_tt *ttm = NULL;
  84         struct page *page;
  85         int ret;
  86         int i;
  87         bool is_iomem;
  88         unsigned long address = (unsigned long)vmf->virtual_address;
  89         int retval = VM_FAULT_NOPAGE;
  90
  91         /*
  92          * Work around locking order reversal in fault / nopfn
  93          * between mmap_sem and bo_reserve: Perform a trylock operation
  94          * for reserve, and if it fails, retry the fault after scheduling.
  95          */
  96
  97         ret = ttm_bo_reserve(bo, true, true, false, 0);
  98         if (unlikely(ret != 0)) {
  99                 if (ret == -EBUSY)
 100                         set_need_resched();
 101                 return VM_FAULT_NOPAGE;
 102         }
 103
 104         if (bdev->driver->fault_reserve_notify)
 105                 bdev->driver->fault_reserve_notify(bo);
 106
 107         /*
 108          * Wait for buffer data in transit, due to a pipelined
 109          * move.
 110          */
 111
 112         spin_lock(&bo->lock);
 113         if (test_bit(TTM_BO_PRIV_FLAG_MOVING, &bo->priv_flags)) {
 114                 ret = ttm_bo_wait(bo, false, true, false);
 115                 spin_unlock(&bo->lock);
 116                 if (unlikely(ret != 0)) {
 117                         retval = (ret != -ERESTARTSYS) ?
 118                             VM_FAULT_SIGBUS : VM_FAULT_NOPAGE;
 119                         goto out_unlock;
 120                 }
 121         } else
 122                 spin_unlock(&bo->lock);
 123
 124
 125         ret = ttm_bo_pci_offset(bdev, &bo->mem, &bus_base, &bus_offset,
 126                                 &bus_size);
 127         if (unlikely(ret != 0)) {
 128                 retval = VM_FAULT_SIGBUS;
 129                 goto out_unlock;
 130         }
 131
 132         is_iomem = (bus_size != 0);
 133
 134         page_offset = ((address - vma->vm_start) >> PAGE_SHIFT) +
 135             bo->vm_node->start - vma->vm_pgoff;
 136         page_last = ((vma->vm_end - vma->vm_start) >> PAGE_SHIFT) +
 137             bo->vm_node->start - vma->vm_pgoff;
 138
 139         if (unlikely(page_offset >= bo->num_pages)) {
 140                 retval = VM_FAULT_SIGBUS;
 141                 goto out_unlock;
 142         }
 143
 144         /*
 145          * Strictly, we're not allowed to modify vma->vm_page_prot here,
 146          * since the mmap_sem is only held in read mode. However, we
 147          * modify only the caching bits of vma->vm_page_prot and
 148          * consider those bits protected by
 149          * the bo->mutex, as we should be the only writers.
 150          * There shouldn't really be any readers of these bits except
 151          * within vm_insert_mixed()? fork?
 152          *
 153          * TODO: Add a list of vmas to the bo, and change the
 154          * vma->vm_page_prot when the object changes caching policy, with
 155          * the correct locks held.
 156          */
 157
 158         if (is_iomem) {
 159                 vma->vm_page_prot = ttm_io_prot(bo->mem.placement,
 160                                                 vma->vm_page_prot);
 161         } else {
 162                 ttm = bo->ttm;
 163                 vma->vm_page_prot = (bo->mem.placement & TTM_PL_FLAG_CACHED) ?
 164                     vm_get_page_prot(vma->vm_flags) :
 165                     ttm_io_prot(bo->mem.placement, vma->vm_page_prot);
 166         }
 167
 168         /*
 169          * Speculatively prefault a number of pages. Only error on
 170          * first page.
 171          */
 172
 173         for (i = 0; i < TTM_BO_VM_NUM_PREFAULT; ++i) {
 174
 175                 if (is_iomem)
 176                         pfn = ((bus_base + bus_offset) >> PAGE_SHIFT) +
 177                             page_offset;
 178                 else {
 179                         page = ttm_tt_get_page(ttm, page_offset);
 180                         if (unlikely(!page && i == 0)) {
 181                                 retval = VM_FAULT_OOM;
 182                                 goto out_unlock;
 183                         } else if (unlikely(!page)) {
 184                                 break;
 185                         }
 186                         pfn = page_to_pfn(page);
 187                 }
 188
 189                 ret = vm_insert_mixed(vma, address, pfn);
 190                 /*
 191                  * Somebody beat us to this PTE or prefaulting to
 192                  * an already populated PTE, or prefaulting error.
 193                  */
 194
 195                 if (unlikely((ret == -EBUSY) || (ret != 0 && i > 0)))
 196                         break;
 197                 else if (unlikely(ret != 0)) {
 198                         retval =
 199                             (ret == -ENOMEM) ? VM_FAULT_OOM : VM_FAULT_SIGBUS;
 200                         goto out_unlock;
 201
 202                 }
 203
 204                 address += PAGE_SIZE;
 205                 if (unlikely(++page_offset >= page_last))
 206                         break;
 207         }
 208
 209 out_unlock:
 210         ttm_bo_unreserve(bo);
 211         return retval;
 212 }
 213
 214 static void ttm_bo_vm_open(struct vm_area_struct *vma)
 215 {
 216         struct ttm_buffer_object *bo =
 217             (struct ttm_buffer_object *)vma->vm_private_data;
 218
 219         (void)ttm_bo_reference(bo);
 220 }
 221
 222 static void ttm_bo_vm_close(struct vm_area_struct *vma)
 223 {
 224         struct ttm_buffer_object *bo =
 225             (struct ttm_buffer_object *)vma->vm_private_data;
 226
 227         ttm_bo_unref(&bo);
 228         vma->vm_private_data = NULL;
 229 }
 230
 231 static const struct vm_operations_struct ttm_bo_vm_ops = {
 232         .fault = ttm_bo_vm_fault,
 233         .open = ttm_bo_vm_open,
 234         .close = ttm_bo_vm_close
 235 };
 236
 237 int ttm_bo_mmap(struct file *filp, struct vm_area_struct *vma,
 238                 struct ttm_bo_device *bdev)
 239 {
 240         struct ttm_bo_driver *driver;
 241         struct ttm_buffer_object *bo;
 242         int ret;
 243
 244         read_lock(&bdev->vm_lock);
 245         bo = ttm_bo_vm_lookup_rb(bdev, vma->vm_pgoff,
 246                                  (vma->vm_end - vma->vm_start) >> PAGE_SHIFT);
 247         if (likely(bo != NULL))
 248                 ttm_bo_reference(bo);
 249         read_unlock(&bdev->vm_lock);
 250
 251         if (unlikely(bo == NULL)) {
 252                 printk(KERN_ERR TTM_PFX
 253                        "Could not find buffer object to map.\n");
 254                 return -EINVAL;
 255         }
 256
 257         driver = bo->bdev->driver;
 258         if (unlikely(!driver->verify_access)) {
 259                 ret = -EPERM;
 260                 goto out_unref;
 261         }
 262         ret = driver->verify_access(bo, filp);
 263         if (unlikely(ret != 0))
 264                 goto out_unref;
 265
 266         vma->vm_ops = &ttm_bo_vm_ops;
 267
 268         /*
 269          * Note: We're transferring the bo reference to
 270          * vma->vm_private_data here.
 271          */
 272
 273         vma->vm_private_data = bo;
 274         vma->vm_flags |= VM_RESERVED | VM_IO | VM_MIXEDMAP | VM_DONTEXPAND;
 275         return 0;
 276 out_unref:
 277         ttm_bo_unref(&bo);
 278         return ret;
 279 }
 280 EXPORT_SYMBOL(ttm_bo_mmap);
 281
 282 int ttm_fbdev_mmap(struct vm_area_struct *vma, struct ttm_buffer_object *bo)
 283 {
 284         if (vma->vm_pgoff != 0)
 285                 return -EACCES;
 286
 287         vma->vm_ops = &ttm_bo_vm_ops;
 288         vma->vm_private_data = ttm_bo_reference(bo);
 289         vma->vm_flags |= VM_RESERVED | VM_IO | VM_MIXEDMAP | VM_DONTEXPAND;
 290         return 0;
 291 }
 292 EXPORT_SYMBOL(ttm_fbdev_mmap);
 293
 294
 295 ssize_t ttm_bo_io(struct ttm_bo_device *bdev, struct file *filp,
 296                   const char __user *wbuf, char __user *rbuf, size_t count,
 297                   loff_t *f_pos, bool write)
 298 {
 299         struct ttm_buffer_object *bo;
 300         struct ttm_bo_driver *driver;
 301         struct ttm_bo_kmap_obj map;
 302         unsigned long dev_offset = (*f_pos >> PAGE_SHIFT);
 303         unsigned long kmap_offset;
 304         unsigned long kmap_end;
 305         unsigned long kmap_num;
 306         size_t io_size;
 307         unsigned int page_offset;
 308         char *virtual;
 309         int ret;
 310         bool no_wait = false;
 311         bool dummy;
 312
 313         read_lock(&bdev->vm_lock);
 314         bo = ttm_bo_vm_lookup_rb(bdev, dev_offset, 1);
 315         if (likely(bo != NULL))
 316                 ttm_bo_reference(bo);
 317         read_unlock(&bdev->vm_lock);
 318
 319         if (unlikely(bo == NULL))
 320                 return -EFAULT;
 321
 322         driver = bo->bdev->driver;
 323         if (unlikely(!driver->verify_access)) {
 324                 ret = -EPERM;
 325                 goto out_unref;
 326         }
 327
 328         ret = driver->verify_access(bo, filp);
 329         if (unlikely(ret != 0))
 330                 goto out_unref;
 331
 332         kmap_offset = dev_offset - bo->vm_node->start;
 333         if (unlikely(kmap_offset >= bo->num_pages)) {
 334                 ret = -EFBIG;
 335                 goto out_unref;
 336         }
 337
 338         page_offset = *f_pos & ~PAGE_MASK;
 339         io_size = bo->num_pages - kmap_offset;
 340         io_size = (io_size << PAGE_SHIFT) - page_offset;
 341         if (count < io_size)
 342                 io_size = count;
 343
 344         kmap_end = (*f_pos + count - 1) >> PAGE_SHIFT;
 345         kmap_num = kmap_end - kmap_offset + 1;
 346
 347         ret = ttm_bo_reserve(bo, true, no_wait, false, 0);
 348
 349         switch (ret) {
 350         case 0:
 351                 break;
 352         case -EBUSY:
 353                 ret = -EAGAIN;
 354                 goto out_unref;
 355         default:
 356                 goto out_unref;
 357         }
 358
 359         ret = ttm_bo_kmap(bo, kmap_offset, kmap_num, &map);
 360         if (unlikely(ret != 0)) {
 361                 ttm_bo_unreserve(bo);
 362                 goto out_unref;
 363         }
 364
 365         virtual = ttm_kmap_obj_virtual(&map, &dummy);
 366         virtual += page_offset;
 367
 368         if (write)
 369                 ret = copy_from_user(virtual, wbuf, io_size);
 370         else
 371                 ret = copy_to_user(rbuf, virtual, io_size);
 372
 373         ttm_bo_kunmap(&map);
 374         ttm_bo_unreserve(bo);
 375         ttm_bo_unref(&bo);
 376
 377         if (unlikely(ret != 0))
 378                 return -EFBIG;
 379
 380         *f_pos += io_size;
 381
 382         return io_size;
 383 out_unref:
 384         ttm_bo_unref(&bo);
 385         return ret;
 386 }
 387
 388 ssize_t ttm_bo_fbdev_io(struct ttm_buffer_object *bo, const char __user *wbuf,
 389                         char __user *rbuf, size_t count, loff_t *f_pos,
 390                         bool write)
 391 {
 392         struct ttm_bo_kmap_obj map;
 393         unsigned long kmap_offset;
 394         unsigned long kmap_end;
 395         unsigned long kmap_num;
 396         size_t io_size;
 397         unsigned int page_offset;
 398         char *virtual;
 399         int ret;
 400         bool no_wait = false;
 401         bool dummy;
 402
 403         kmap_offset = (*f_pos >> PAGE_SHIFT);
 404         if (unlikely(kmap_offset >= bo->num_pages))
 405                 return -EFBIG;
 406
 407         page_offset = *f_pos & ~PAGE_MASK;
 408         io_size = bo->num_pages - kmap_offset;
 409         io_size = (io_size << PAGE_SHIFT) - page_offset;
 410         if (count < io_size)
 411                 io_size = count;
 412
 413         kmap_end = (*f_pos + count - 1) >> PAGE_SHIFT;
 414         kmap_num = kmap_end - kmap_offset + 1;
 415
 416         ret = ttm_bo_reserve(bo, true, no_wait, false, 0);
 417
 418         switch (ret) {
 419         case 0:
 420                 break;
 421         case -EBUSY:
 422                 return -EAGAIN;
 423         default:
 424                 return ret;
 425         }
 426
 427         ret = ttm_bo_kmap(bo, kmap_offset, kmap_num, &map);
 428         if (unlikely(ret != 0)) {
 429                 ttm_bo_unreserve(bo);
 430                 return ret;
 431         }
 432
 433         virtual = ttm_kmap_obj_virtual(&map, &dummy);
 434         virtual += page_offset;
 435
 436         if (write)
 437                 ret = copy_from_user(virtual, wbuf, io_size);
 438         else
 439                 ret = copy_to_user(rbuf, virtual, io_size);
 440
 441         ttm_bo_kunmap(&map);
 442         ttm_bo_unreserve(bo);
 443         ttm_bo_unref(&bo);
 444
 445         if (unlikely(ret != 0))
 446                 return ret;
 447
 448         *f_pos += io_size;
 449
 450         return io_size;
 451 }