linux-core/drm_compat.c

   1 /**************************************************************************
   2  *
   3  * This kernel module is free software; you can redistribute it and/or
   4  * modify it under the terms of the GNU General Public License as
   5  * published by the Free Software Foundation; either version 2 of the
   6  * License, or (at your option) any later version.
   7  *
   8  * This program is distributed in the hope that it will be useful, but
   9  * WITHOUT ANY WARRANTY; without even the implied warranty of
  10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  11  * General Public License for more details.
  12  *
  13  * You should have received a copy of the GNU General Public License
  14  * along with this program; if not, write to the Free Software
  15  * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  16  *
  17  **************************************************************************/
  18 /*
  19  * This code provides access to unexported mm kernel features. It is necessary
  20  * to use the new DRM memory manager code with kernels that don't support it
  21  * directly.
  22  *
  23  * Authors: Thomas Hellstrom <thomas-at-tungstengraphics-dot-com>
  24  *          Linux kernel mm subsystem authors.
  25  *          (Most code taken from there).
  26  */
  27
  28 #include "drmP.h"
  29
  30 #if defined(CONFIG_X86) && (LINUX_VERSION_CODE < KERNEL_VERSION(2,6,15))
  31
  32 /*
  33  * These have bad performance in the AGP module for the indicated kernel versions.
  34  */
  35
  36 int drm_map_page_into_agp(struct page *page)
  37 {
  38         int i;
  39         i = change_page_attr(page, 1, PAGE_KERNEL_NOCACHE);
  40         /* Caller's responsibility to call global_flush_tlb() for
  41          * performance reasons */
  42         return i;
  43 }
  44
  45 int drm_unmap_page_from_agp(struct page *page)
  46 {
  47         int i;
  48         i = change_page_attr(page, 1, PAGE_KERNEL);
  49         /* Caller's responsibility to call global_flush_tlb() for
  50          * performance reasons */
  51         return i;
  52 }
  53 #endif
  54
  55
  56 #if  (LINUX_VERSION_CODE < KERNEL_VERSION(2,6,19))
  57
  58 /*
  59  * The protection map was exported in 2.6.19
  60  */
  61
  62 pgprot_t vm_get_page_prot(unsigned long vm_flags)
  63 {
  64 #ifdef MODULE
  65         static pgprot_t drm_protection_map[16] = {
  66                 __P000, __P001, __P010, __P011, __P100, __P101, __P110, __P111,
  67                 __S000, __S001, __S010, __S011, __S100, __S101, __S110, __S111
  68         };
  69
  70         return drm_protection_map[vm_flags & 0x0F];
  71 #else
  72         extern pgprot_t protection_map[];
  73         return protection_map[vm_flags & 0x0F];
  74 #endif
  75 };
  76 #endif
  77
  78
  79 #if (LINUX_VERSION_CODE < KERNEL_VERSION(2,6,15))
  80
  81 /*
  82  * vm code for kernels below 2.6.15 in which version a major vm write
  83  * occured. This implement a simple straightforward
  84  * version similar to what's going to be
  85  * in kernel 2.6.19+
  86  * Kernels below 2.6.15 use nopage whereas 2.6.19 and upwards use
  87  * nopfn.
  88  */
  89
  90 static struct {
  91         spinlock_t lock;
  92         struct page *dummy_page;
  93         atomic_t present;
  94 } drm_np_retry =
  95 {SPIN_LOCK_UNLOCKED, NOPAGE_OOM, ATOMIC_INIT(0)};
  96
  97
  98 static struct page *drm_bo_vm_fault(struct vm_area_struct *vma,
  99                                     struct fault_data *data);
 100
 101
 102 struct page * get_nopage_retry(void)
 103 {
 104         if (atomic_read(&drm_np_retry.present) == 0) {
 105                 struct page *page = alloc_page(GFP_KERNEL);
 106                 if (!page)
 107                         return NOPAGE_OOM;
 108                 spin_lock(&drm_np_retry.lock);
 109                 drm_np_retry.dummy_page = page;
 110                 atomic_set(&drm_np_retry.present,1);
 111                 spin_unlock(&drm_np_retry.lock);
 112         }
 113         get_page(drm_np_retry.dummy_page);
 114         return drm_np_retry.dummy_page;
 115 }
 116
 117 void free_nopage_retry(void)
 118 {
 119         if (atomic_read(&drm_np_retry.present) == 1) {
 120                 spin_lock(&drm_np_retry.lock);
 121                 __free_page(drm_np_retry.dummy_page);
 122                 drm_np_retry.dummy_page = NULL;
 123                 atomic_set(&drm_np_retry.present, 0);
 124                 spin_unlock(&drm_np_retry.lock);
 125         }
 126 }
 127
 128 struct page *drm_bo_vm_nopage(struct vm_area_struct *vma,
 129                                unsigned long address,
 130                                int *type)
 131 {
 132         struct fault_data data;
 133
 134         if (type)
 135                 *type = VM_FAULT_MINOR;
 136
 137         data.address = address;
 138         data.vma = vma;
 139         drm_bo_vm_fault(vma, &data);
 140         switch (data.type) {
 141         case VM_FAULT_OOM:
 142                 return NOPAGE_OOM;
 143         case VM_FAULT_SIGBUS:
 144                 return NOPAGE_SIGBUS;
 145         default:
 146                 break;
 147         }
 148
 149         return NOPAGE_REFAULT;
 150 }
 151
 152 #endif
 153
 154 #if !defined(DRM_FULL_MM_COMPAT) && \
 155   ((LINUX_VERSION_CODE < KERNEL_VERSION(2,6,15)) || \
 156    (LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,19)))
 157
 158 static int drm_pte_is_clear(struct vm_area_struct *vma,
 159                             unsigned long addr)
 160 {
 161         struct mm_struct *mm = vma->vm_mm;
 162         int ret = 1;
 163         pte_t *pte;
 164         pmd_t *pmd;
 165         pud_t *pud;
 166         pgd_t *pgd;
 167
 168         spin_lock(&mm->page_table_lock);
 169         pgd = pgd_offset(mm, addr);
 170         if (pgd_none(*pgd))
 171                 goto unlock;
 172         pud = pud_offset(pgd, addr);
 173         if (pud_none(*pud))
 174                 goto unlock;
 175         pmd = pmd_offset(pud, addr);
 176         if (pmd_none(*pmd))
 177                 goto unlock;
 178         pte = pte_offset_map(pmd, addr);
 179         if (!pte)
 180                 goto unlock;
 181         ret = pte_none(*pte);
 182         pte_unmap(pte);
 183  unlock:
 184         spin_unlock(&mm->page_table_lock);
 185         return ret;
 186 }
 187
 188 static int vm_insert_pfn(struct vm_area_struct *vma, unsigned long addr,
 189                   unsigned long pfn)
 190 {
 191         int ret;
 192         if (!drm_pte_is_clear(vma, addr))
 193                 return -EBUSY;
 194
 195         ret = io_remap_pfn_range(vma, addr, pfn, PAGE_SIZE, vma->vm_page_prot);
 196         return ret;
 197 }
 198
 199 static struct page *drm_bo_vm_fault(struct vm_area_struct *vma,
 200                                     struct fault_data *data)
 201 {
 202         unsigned long address = data->address;
 203         drm_buffer_object_t *bo = (drm_buffer_object_t *) vma->vm_private_data;
 204         unsigned long page_offset;
 205         struct page *page = NULL;
 206         drm_ttm_t *ttm;
 207         drm_device_t *dev;
 208         unsigned long pfn;
 209         int err;
 210         unsigned long bus_base;
 211         unsigned long bus_offset;
 212         unsigned long bus_size;
 213
 214
 215         mutex_lock(&bo->mutex);
 216
 217         err = drm_bo_wait(bo, 0, 1, 0);
 218         if (err) {
 219                 data->type = (err == -EAGAIN) ?
 220                         VM_FAULT_MINOR : VM_FAULT_SIGBUS;
 221                 goto out_unlock;
 222         }
 223
 224
 225         /*
 226          * If buffer happens to be in a non-mappable location,
 227          * move it to a mappable.
 228          */
 229
 230         if (!(bo->mem.flags & DRM_BO_FLAG_MAPPABLE)) {
 231                 unsigned long _end = jiffies + 3*DRM_HZ;
 232                 uint32_t new_mask = bo->mem.mask |
 233                         DRM_BO_FLAG_MAPPABLE |
 234                         DRM_BO_FLAG_FORCE_MAPPABLE;
 235
 236                 do {
 237                         err = drm_bo_move_buffer(bo, new_mask, 0, 0);
 238                 } while((err == -EAGAIN) && !time_after_eq(jiffies, _end));
 239
 240                 if (err) {
 241                         DRM_ERROR("Timeout moving buffer to mappable location.\n");
 242                         data->type = VM_FAULT_SIGBUS;
 243                         goto out_unlock;
 244                 }
 245         }
 246
 247         if (address > vma->vm_end) {
 248                 data->type = VM_FAULT_SIGBUS;
 249                 goto out_unlock;
 250         }
 251
 252         dev = bo->dev;
 253         err = drm_bo_pci_offset(dev, &bo->mem, &bus_base, &bus_offset,
 254                                 &bus_size);
 255
 256         if (err) {
 257                 data->type = VM_FAULT_SIGBUS;
 258                 goto out_unlock;
 259         }
 260
 261         page_offset = (address - vma->vm_start) >> PAGE_SHIFT;
 262
 263         if (bus_size) {
 264                 drm_mem_type_manager_t *man = &dev->bm.man[bo->mem.mem_type];
 265
 266                 pfn = ((bus_base + bus_offset) >> PAGE_SHIFT) + page_offset;
 267                 vma->vm_page_prot = drm_io_prot(man->drm_bus_maptype, vma);
 268         } else {
 269                 ttm = bo->ttm;
 270
 271                 drm_ttm_fixup_caching(ttm);
 272                 page = drm_ttm_get_page(ttm, page_offset);
 273                 if (!page) {
 274                         data->type = VM_FAULT_OOM;
 275                         goto out_unlock;
 276                 }
 277                 pfn = page_to_pfn(page);
 278                 vma->vm_page_prot = vm_get_page_prot(vma->vm_flags);
 279         }
 280
 281         err = vm_insert_pfn(vma, address, pfn);
 282
 283         if (!err || err == -EBUSY)
 284                 data->type = VM_FAULT_MINOR;
 285         else
 286                 data->type = VM_FAULT_OOM;
 287 out_unlock:
 288         mutex_unlock(&bo->mutex);
 289         return NULL;
 290 }
 291
 292 #endif
 293
 294 #if (LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,19)) && \
 295   !defined(DRM_FULL_MM_COMPAT)
 296
 297 /**
 298  */
 299
 300 unsigned long drm_bo_vm_nopfn(struct vm_area_struct * vma,
 301                            unsigned long address)
 302 {
 303         struct fault_data data;
 304         data.address = address;
 305
 306         (void) drm_bo_vm_fault(vma, &data);
 307         if (data.type == VM_FAULT_OOM)
 308                 return NOPFN_OOM;
 309         else if (data.type == VM_FAULT_SIGBUS)
 310                 return NOPFN_SIGBUS;
 311
 312         /*
 313          * pfn already set.
 314          */
 315
 316         return 0;
 317 }
 318 #endif
 319
 320
 321 #ifdef DRM_ODD_MM_COMPAT
 322
 323 /*
 324  * VM compatibility code for 2.6.15-2.6.18. This code implements a complicated
 325  * workaround for a single BUG statement in do_no_page in these versions. The
 326  * tricky thing is that we need to take the mmap_sem in exclusive mode for _all_
 327  * vmas mapping the ttm, before dev->struct_mutex is taken. The way we do this is to
 328  * check first take the dev->struct_mutex, and then trylock all mmap_sems. If this
 329  * fails for a single mmap_sem, we have to release all sems and the dev->struct_mutex,
 330  * release the cpu and retry. We also need to keep track of all vmas mapping the ttm.
 331  * phew.
 332  */
 333
 334 typedef struct p_mm_entry {
 335         struct list_head head;
 336         struct mm_struct *mm;
 337         atomic_t refcount;
 338         int locked;
 339 } p_mm_entry_t;
 340
 341 typedef struct vma_entry {
 342         struct list_head head;
 343         struct vm_area_struct *vma;
 344 } vma_entry_t;
 345
 346
 347 struct page *drm_bo_vm_nopage(struct vm_area_struct *vma,
 348                                unsigned long address,
 349                                int *type)
 350 {
 351         drm_buffer_object_t *bo = (drm_buffer_object_t *) vma->vm_private_data;
 352         unsigned long page_offset;
 353         struct page *page;
 354         drm_ttm_t *ttm;
 355         drm_device_t *dev;
 356
 357         mutex_lock(&bo->mutex);
 358
 359         if (type)
 360                 *type = VM_FAULT_MINOR;
 361
 362         if (address > vma->vm_end) {
 363                 page = NOPAGE_SIGBUS;
 364                 goto out_unlock;
 365         }
 366
 367         dev = bo->dev;
 368
 369         if (drm_mem_reg_is_pci(dev, &bo->mem)) {
 370                 DRM_ERROR("Invalid compat nopage.\n");
 371                 page = NOPAGE_SIGBUS;
 372                 goto out_unlock;
 373         }
 374
 375         ttm = bo->ttm;
 376         drm_ttm_fixup_caching(ttm);
 377         page_offset = (address - vma->vm_start) >> PAGE_SHIFT;
 378         page = drm_ttm_get_page(ttm, page_offset);
 379         if (!page) {
 380                 page = NOPAGE_OOM;
 381                 goto out_unlock;
 382         }
 383
 384         get_page(page);
 385 out_unlock:
 386         mutex_unlock(&bo->mutex);
 387         return page;
 388 }
 389
 390
 391
 392
 393 int drm_bo_map_bound(struct vm_area_struct *vma)
 394 {
 395         drm_buffer_object_t *bo = (drm_buffer_object_t *)vma->vm_private_data;
 396         int ret = 0;
 397         unsigned long bus_base;
 398         unsigned long bus_offset;
 399         unsigned long bus_size;
 400
 401         ret = drm_bo_pci_offset(bo->dev, &bo->mem, &bus_base,
 402                                 &bus_offset, &bus_size);
 403         BUG_ON(ret);
 404
 405         if (bus_size) {
 406                 drm_mem_type_manager_t *man = &bo->dev->bm.man[bo->mem.mem_type];
 407                 unsigned long pfn = (bus_base + bus_offset) >> PAGE_SHIFT;
 408                 pgprot_t pgprot = drm_io_prot(man->drm_bus_maptype, vma);
 409                 ret = io_remap_pfn_range(vma, vma->vm_start, pfn,
 410                                          vma->vm_end - vma->vm_start,
 411                                          pgprot);
 412         }
 413
 414         return ret;
 415 }
 416
 417
 418 int drm_bo_add_vma(drm_buffer_object_t * bo, struct vm_area_struct *vma)
 419 {
 420         p_mm_entry_t *entry, *n_entry;
 421         vma_entry_t *v_entry;
 422         struct mm_struct *mm = vma->vm_mm;
 423
 424         v_entry = drm_ctl_alloc(sizeof(*v_entry), DRM_MEM_BUFOBJ);
 425         if (!v_entry) {
 426                 DRM_ERROR("Allocation of vma pointer entry failed\n");
 427                 return -ENOMEM;
 428         }
 429         v_entry->vma = vma;
 430
 431         list_add_tail(&v_entry->head, &bo->vma_list);
 432
 433         list_for_each_entry(entry, &bo->p_mm_list, head) {
 434                 if (mm == entry->mm) {
 435                         atomic_inc(&entry->refcount);
 436                         return 0;
 437                 } else if ((unsigned long)mm < (unsigned long)entry->mm) ;
 438         }
 439
 440         n_entry = drm_ctl_alloc(sizeof(*n_entry), DRM_MEM_BUFOBJ);
 441         if (!n_entry) {
 442                 DRM_ERROR("Allocation of process mm pointer entry failed\n");
 443                 return -ENOMEM;
 444         }
 445         INIT_LIST_HEAD(&n_entry->head);
 446         n_entry->mm = mm;
 447         n_entry->locked = 0;
 448         atomic_set(&n_entry->refcount, 0);
 449         list_add_tail(&n_entry->head, &entry->head);
 450
 451         return 0;
 452 }
 453
 454 void drm_bo_delete_vma(drm_buffer_object_t * bo, struct vm_area_struct *vma)
 455 {
 456         p_mm_entry_t *entry, *n;
 457         vma_entry_t *v_entry, *v_n;
 458         int found = 0;
 459         struct mm_struct *mm = vma->vm_mm;
 460
 461         list_for_each_entry_safe(v_entry, v_n, &bo->vma_list, head) {
 462                 if (v_entry->vma == vma) {
 463                         found = 1;
 464                         list_del(&v_entry->head);
 465                         drm_ctl_free(v_entry, sizeof(*v_entry), DRM_MEM_BUFOBJ);
 466                         break;
 467                 }
 468         }
 469         BUG_ON(!found);
 470
 471         list_for_each_entry_safe(entry, n, &bo->p_mm_list, head) {
 472                 if (mm == entry->mm) {
 473                         if (atomic_add_negative(-1, &entry->refcount)) {
 474                                 list_del(&entry->head);
 475                                 BUG_ON(entry->locked);
 476                                 drm_ctl_free(entry, sizeof(*entry), DRM_MEM_BUFOBJ);
 477                         }
 478                         return;
 479                 }
 480         }
 481         BUG_ON(1);
 482 }
 483
 484
 485
 486 int drm_bo_lock_kmm(drm_buffer_object_t * bo)
 487 {
 488         p_mm_entry_t *entry;
 489         int lock_ok = 1;
 490
 491         list_for_each_entry(entry, &bo->p_mm_list, head) {
 492                 BUG_ON(entry->locked);
 493                 if (!down_write_trylock(&entry->mm->mmap_sem)) {
 494                         lock_ok = 0;
 495                         break;
 496                 }
 497                 entry->locked = 1;
 498         }
 499
 500         if (lock_ok)
 501                 return 0;
 502
 503         list_for_each_entry(entry, &bo->p_mm_list, head) {
 504                 if (!entry->locked)
 505                         break;
 506                 up_write(&entry->mm->mmap_sem);
 507                 entry->locked = 0;
 508         }
 509
 510         /*
 511          * Possible deadlock. Try again. Our callers should handle this
 512          * and restart.
 513          */
 514
 515         return -EAGAIN;
 516 }
 517
 518 void drm_bo_unlock_kmm(drm_buffer_object_t * bo)
 519 {
 520         p_mm_entry_t *entry;
 521
 522         list_for_each_entry(entry, &bo->p_mm_list, head) {
 523                 BUG_ON(!entry->locked);
 524                 up_write(&entry->mm->mmap_sem);
 525                 entry->locked = 0;
 526         }
 527 }
 528
 529 int drm_bo_remap_bound(drm_buffer_object_t *bo)
 530 {
 531         vma_entry_t *v_entry;
 532         int ret = 0;
 533
 534         if (drm_mem_reg_is_pci(bo->dev, &bo->mem)) {
 535                 list_for_each_entry(v_entry, &bo->vma_list, head) {
 536                         ret = drm_bo_map_bound(v_entry->vma);
 537                         if (ret)
 538                                 break;
 539                 }
 540         }
 541
 542         return ret;
 543 }
 544
 545 void drm_bo_finish_unmap(drm_buffer_object_t *bo)
 546 {
 547         vma_entry_t *v_entry;
 548
 549         list_for_each_entry(v_entry, &bo->vma_list, head) {
 550                 v_entry->vma->vm_flags &= ~VM_PFNMAP;
 551         }
 552 }
 553
 554 #endif
 555