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 = (bo->mem.flags & DRM_BO_FLAG_CACHED) ?
 279                         vm_get_page_prot(vma->vm_flags) :
 280                         drm_io_prot(_DRM_TTM, vma);
 281         }
 282
 283         err = vm_insert_pfn(vma, address, pfn);
 284
 285         if (!err || err == -EBUSY)
 286                 data->type = VM_FAULT_MINOR;
 287         else
 288                 data->type = VM_FAULT_OOM;
 289 out_unlock:
 290         mutex_unlock(&bo->mutex);
 291         return NULL;
 292 }
 293
 294 #endif
 295
 296 #if (LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,19)) && \
 297   !defined(DRM_FULL_MM_COMPAT)
 298
 299 /**
 300  */
 301
 302 unsigned long drm_bo_vm_nopfn(struct vm_area_struct * vma,
 303                            unsigned long address)
 304 {
 305         struct fault_data data;
 306         data.address = address;
 307
 308         (void) drm_bo_vm_fault(vma, &data);
 309         if (data.type == VM_FAULT_OOM)
 310                 return NOPFN_OOM;
 311         else if (data.type == VM_FAULT_SIGBUS)
 312                 return NOPFN_SIGBUS;
 313
 314         /*
 315          * pfn already set.
 316          */
 317
 318         return 0;
 319 }
 320 #endif
 321
 322
 323 #ifdef DRM_ODD_MM_COMPAT
 324
 325 /*
 326  * VM compatibility code for 2.6.15-2.6.18. This code implements a complicated
 327  * workaround for a single BUG statement in do_no_page in these versions. The
 328  * tricky thing is that we need to take the mmap_sem in exclusive mode for _all_
 329  * vmas mapping the ttm, before dev->struct_mutex is taken. The way we do this is to
 330  * check first take the dev->struct_mutex, and then trylock all mmap_sems. If this
 331  * fails for a single mmap_sem, we have to release all sems and the dev->struct_mutex,
 332  * release the cpu and retry. We also need to keep track of all vmas mapping the ttm.
 333  * phew.
 334  */
 335
 336 typedef struct p_mm_entry {
 337         struct list_head head;
 338         struct mm_struct *mm;
 339         atomic_t refcount;
 340         int locked;
 341 } p_mm_entry_t;
 342
 343 typedef struct vma_entry {
 344         struct list_head head;
 345         struct vm_area_struct *vma;
 346 } vma_entry_t;
 347
 348
 349 struct page *drm_bo_vm_nopage(struct vm_area_struct *vma,
 350                                unsigned long address,
 351                                int *type)
 352 {
 353         drm_buffer_object_t *bo = (drm_buffer_object_t *) vma->vm_private_data;
 354         unsigned long page_offset;
 355         struct page *page;
 356         drm_ttm_t *ttm;
 357         drm_device_t *dev;
 358
 359         mutex_lock(&bo->mutex);
 360
 361         if (type)
 362                 *type = VM_FAULT_MINOR;
 363
 364         if (address > vma->vm_end) {
 365                 page = NOPAGE_SIGBUS;
 366                 goto out_unlock;
 367         }
 368
 369         dev = bo->dev;
 370
 371         if (drm_mem_reg_is_pci(dev, &bo->mem)) {
 372                 DRM_ERROR("Invalid compat nopage.\n");
 373                 page = NOPAGE_SIGBUS;
 374                 goto out_unlock;
 375         }
 376
 377         ttm = bo->ttm;
 378         drm_ttm_fixup_caching(ttm);
 379         page_offset = (address - vma->vm_start) >> PAGE_SHIFT;
 380         page = drm_ttm_get_page(ttm, page_offset);
 381         if (!page) {
 382                 page = NOPAGE_OOM;
 383                 goto out_unlock;
 384         }
 385
 386         get_page(page);
 387 out_unlock:
 388         mutex_unlock(&bo->mutex);
 389         return page;
 390 }
 391
 392
 393
 394
 395 int drm_bo_map_bound(struct vm_area_struct *vma)
 396 {
 397         drm_buffer_object_t *bo = (drm_buffer_object_t *)vma->vm_private_data;
 398         int ret = 0;
 399         unsigned long bus_base;
 400         unsigned long bus_offset;
 401         unsigned long bus_size;
 402
 403         ret = drm_bo_pci_offset(bo->dev, &bo->mem, &bus_base,
 404                                 &bus_offset, &bus_size);
 405         BUG_ON(ret);
 406
 407         if (bus_size) {
 408                 drm_mem_type_manager_t *man = &bo->dev->bm.man[bo->mem.mem_type];
 409                 unsigned long pfn = (bus_base + bus_offset) >> PAGE_SHIFT;
 410                 pgprot_t pgprot = drm_io_prot(man->drm_bus_maptype, vma);
 411                 ret = io_remap_pfn_range(vma, vma->vm_start, pfn,
 412                                          vma->vm_end - vma->vm_start,
 413                                          pgprot);
 414         }
 415
 416         return ret;
 417 }
 418
 419
 420 int drm_bo_add_vma(drm_buffer_object_t * bo, struct vm_area_struct *vma)
 421 {
 422         p_mm_entry_t *entry, *n_entry;
 423         vma_entry_t *v_entry;
 424         struct mm_struct *mm = vma->vm_mm;
 425
 426         v_entry = drm_ctl_alloc(sizeof(*v_entry), DRM_MEM_BUFOBJ);
 427         if (!v_entry) {
 428                 DRM_ERROR("Allocation of vma pointer entry failed\n");
 429                 return -ENOMEM;
 430         }
 431         v_entry->vma = vma;
 432
 433         list_add_tail(&v_entry->head, &bo->vma_list);
 434
 435         list_for_each_entry(entry, &bo->p_mm_list, head) {
 436                 if (mm == entry->mm) {
 437                         atomic_inc(&entry->refcount);
 438                         return 0;
 439                 } else if ((unsigned long)mm < (unsigned long)entry->mm) ;
 440         }
 441
 442         n_entry = drm_ctl_alloc(sizeof(*n_entry), DRM_MEM_BUFOBJ);
 443         if (!n_entry) {
 444                 DRM_ERROR("Allocation of process mm pointer entry failed\n");
 445                 return -ENOMEM;
 446         }
 447         INIT_LIST_HEAD(&n_entry->head);
 448         n_entry->mm = mm;
 449         n_entry->locked = 0;
 450         atomic_set(&n_entry->refcount, 0);
 451         list_add_tail(&n_entry->head, &entry->head);
 452
 453         return 0;
 454 }
 455
 456 void drm_bo_delete_vma(drm_buffer_object_t * bo, struct vm_area_struct *vma)
 457 {
 458         p_mm_entry_t *entry, *n;
 459         vma_entry_t *v_entry, *v_n;
 460         int found = 0;
 461         struct mm_struct *mm = vma->vm_mm;
 462
 463         list_for_each_entry_safe(v_entry, v_n, &bo->vma_list, head) {
 464                 if (v_entry->vma == vma) {
 465                         found = 1;
 466                         list_del(&v_entry->head);
 467                         drm_ctl_free(v_entry, sizeof(*v_entry), DRM_MEM_BUFOBJ);
 468                         break;
 469                 }
 470         }
 471         BUG_ON(!found);
 472
 473         list_for_each_entry_safe(entry, n, &bo->p_mm_list, head) {
 474                 if (mm == entry->mm) {
 475                         if (atomic_add_negative(-1, &entry->refcount)) {
 476                                 list_del(&entry->head);
 477                                 BUG_ON(entry->locked);
 478                                 drm_ctl_free(entry, sizeof(*entry), DRM_MEM_BUFOBJ);
 479                         }
 480                         return;
 481                 }
 482         }
 483         BUG_ON(1);
 484 }
 485
 486
 487
 488 int drm_bo_lock_kmm(drm_buffer_object_t * bo)
 489 {
 490         p_mm_entry_t *entry;
 491         int lock_ok = 1;
 492
 493         list_for_each_entry(entry, &bo->p_mm_list, head) {
 494                 BUG_ON(entry->locked);
 495                 if (!down_write_trylock(&entry->mm->mmap_sem)) {
 496                         lock_ok = 0;
 497                         break;
 498                 }
 499                 entry->locked = 1;
 500         }
 501
 502         if (lock_ok)
 503                 return 0;
 504
 505         list_for_each_entry(entry, &bo->p_mm_list, head) {
 506                 if (!entry->locked)
 507                         break;
 508                 up_write(&entry->mm->mmap_sem);
 509                 entry->locked = 0;
 510         }
 511
 512         /*
 513          * Possible deadlock. Try again. Our callers should handle this
 514          * and restart.
 515          */
 516
 517         return -EAGAIN;
 518 }
 519
 520 void drm_bo_unlock_kmm(drm_buffer_object_t * bo)
 521 {
 522         p_mm_entry_t *entry;
 523
 524         list_for_each_entry(entry, &bo->p_mm_list, head) {
 525                 BUG_ON(!entry->locked);
 526                 up_write(&entry->mm->mmap_sem);
 527                 entry->locked = 0;
 528         }
 529 }
 530
 531 int drm_bo_remap_bound(drm_buffer_object_t *bo)
 532 {
 533         vma_entry_t *v_entry;
 534         int ret = 0;
 535
 536         if (drm_mem_reg_is_pci(bo->dev, &bo->mem)) {
 537                 list_for_each_entry(v_entry, &bo->vma_list, head) {
 538                         ret = drm_bo_map_bound(v_entry->vma);
 539                         if (ret)
 540                                 break;
 541                 }
 542         }
 543
 544         return ret;
 545 }
 546
 547 void drm_bo_finish_unmap(drm_buffer_object_t *bo)
 548 {
 549         vma_entry_t *v_entry;
 550
 551         list_for_each_entry(v_entry, &bo->vma_list, head) {
 552                 v_entry->vma->vm_flags &= ~VM_PFNMAP;
 553         }
 554 }
 555
 556 #endif
 557