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   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 <linux/vmalloc.h>
  32 #include <linux/sched.h>
  33 #include <linux/highmem.h>
  34 #include <linux/pagemap.h>
  35 #include <linux/file.h>
  36 #include <linux/swap.h>
  37 #include "ttm/ttm_module.h"
  38 #include "ttm/ttm_bo_driver.h"
  39 #include "ttm/ttm_placement.h"
  40
  41 static int ttm_tt_swapin(struct ttm_tt *ttm);
  42
  43 #if defined(CONFIG_X86)
  44 static void ttm_tt_clflush_page(struct page *page)
  45 {
  46         uint8_t *page_virtual;
  47         unsigned int i;
  48
  49         if (unlikely(page == NULL))
  50                 return;
  51
  52         page_virtual = kmap_atomic(page, KM_USER0);
  53
  54         for (i = 0; i < PAGE_SIZE; i += boot_cpu_data.x86_clflush_size)
  55                 clflush(page_virtual + i);
  56
  57         kunmap_atomic(page_virtual, KM_USER0);
  58 }
  59
  60 static void ttm_tt_cache_flush_clflush(struct page *pages[],
  61                                        unsigned long num_pages)
  62 {
  63         unsigned long i;
  64
  65         mb();
  66         for (i = 0; i < num_pages; ++i)
  67                 ttm_tt_clflush_page(*pages++);
  68         mb();
  69 }
  70 #elif !defined(__powerpc__)
  71 static void ttm_tt_ipi_handler(void *null)
  72 {
  73         ;
  74 }
  75 #endif
  76
  77 void ttm_tt_cache_flush(struct page *pages[], unsigned long num_pages)
  78 {
  79
  80 #if defined(CONFIG_X86)
  81         if (cpu_has_clflush) {
  82                 ttm_tt_cache_flush_clflush(pages, num_pages);
  83                 return;
  84         }
  85 #elif defined(__powerpc__)
  86         unsigned long i;
  87
  88         for (i = 0; i < num_pages; ++i) {
  89                 if (pages[i]) {
  90                         unsigned long start = (unsigned long)page_address(pages[i]);
  91                         flush_dcache_range(start, start + PAGE_SIZE);
  92                 }
  93         }
  94 #else
  95         if (on_each_cpu(ttm_tt_ipi_handler, NULL, 1) != 0)
  96                 printk(KERN_ERR TTM_PFX
  97                        "Timed out waiting for drm cache flush.\n");
  98 #endif
  99 }
 100
 101 /**
 102  * Allocates storage for pointers to the pages that back the ttm.
 103  *
 104  * Uses kmalloc if possible. Otherwise falls back to vmalloc.
 105  */
 106 static void ttm_tt_alloc_page_directory(struct ttm_tt *ttm)
 107 {
 108         unsigned long size = ttm->num_pages * sizeof(*ttm->pages);
 109         ttm->pages = NULL;
 110
 111         if (size <= PAGE_SIZE)
 112                 ttm->pages = kzalloc(size, GFP_KERNEL);
 113
 114         if (!ttm->pages) {
 115                 ttm->pages = vmalloc_user(size);
 116                 if (ttm->pages)
 117                         ttm->page_flags |= TTM_PAGE_FLAG_VMALLOC;
 118         }
 119 }
 120
 121 static void ttm_tt_free_page_directory(struct ttm_tt *ttm)
 122 {
 123         if (ttm->page_flags & TTM_PAGE_FLAG_VMALLOC) {
 124                 vfree(ttm->pages);
 125                 ttm->page_flags &= ~TTM_PAGE_FLAG_VMALLOC;
 126         } else {
 127                 kfree(ttm->pages);
 128         }
 129         ttm->pages = NULL;
 130 }
 131
 132 static struct page *ttm_tt_alloc_page(unsigned page_flags)
 133 {
 134         if (page_flags & TTM_PAGE_FLAG_ZERO_ALLOC)
 135                 return alloc_page(GFP_HIGHUSER | __GFP_ZERO);
 136
 137         return alloc_page(GFP_HIGHUSER);
 138 }
 139
 140 static void ttm_tt_free_user_pages(struct ttm_tt *ttm)
 141 {
 142         int write;
 143         int dirty;
 144         struct page *page;
 145         int i;
 146         struct ttm_backend *be = ttm->be;
 147
 148         BUG_ON(!(ttm->page_flags & TTM_PAGE_FLAG_USER));
 149         write = ((ttm->page_flags & TTM_PAGE_FLAG_WRITE) != 0);
 150         dirty = ((ttm->page_flags & TTM_PAGE_FLAG_USER_DIRTY) != 0);
 151
 152         if (be)
 153                 be->func->clear(be);
 154
 155         for (i = 0; i < ttm->num_pages; ++i) {
 156                 page = ttm->pages[i];
 157                 if (page == NULL)
 158                         continue;
 159
 160                 if (page == ttm->dummy_read_page) {
 161                         BUG_ON(write);
 162                         continue;
 163                 }
 164
 165                 if (write && dirty && !PageReserved(page))
 166                         set_page_dirty_lock(page);
 167
 168                 ttm->pages[i] = NULL;
 169                 ttm_mem_global_free(ttm->bdev->mem_glob, PAGE_SIZE);
 170                 put_page(page);
 171         }
 172         ttm->state = tt_unpopulated;
 173         ttm->first_himem_page = ttm->num_pages;
 174         ttm->last_lomem_page = -1;
 175 }
 176
 177 static struct page *__ttm_tt_get_page(struct ttm_tt *ttm, int index)
 178 {
 179         struct page *p;
 180         struct ttm_bo_device *bdev = ttm->bdev;
 181         struct ttm_mem_global *mem_glob = bdev->mem_glob;
 182         int ret;
 183
 184         while (NULL == (p = ttm->pages[index])) {
 185                 p = ttm_tt_alloc_page(ttm->page_flags);
 186
 187                 if (!p)
 188                         return NULL;
 189
 190                 ret = ttm_mem_global_alloc_page(mem_glob, p, false, false);
 191                 if (unlikely(ret != 0))
 192                         goto out_err;
 193
 194                 if (PageHighMem(p))
 195                         ttm->pages[--ttm->first_himem_page] = p;
 196                 else
 197                         ttm->pages[++ttm->last_lomem_page] = p;
 198         }
 199         return p;
 200 out_err:
 201         put_page(p);
 202         return NULL;
 203 }
 204
 205 struct page *ttm_tt_get_page(struct ttm_tt *ttm, int index)
 206 {
 207         int ret;
 208
 209         if (unlikely(ttm->page_flags & TTM_PAGE_FLAG_SWAPPED)) {
 210                 ret = ttm_tt_swapin(ttm);
 211                 if (unlikely(ret != 0))
 212                         return NULL;
 213         }
 214         return __ttm_tt_get_page(ttm, index);
 215 }
 216
 217 int ttm_tt_populate(struct ttm_tt *ttm)
 218 {
 219         struct page *page;
 220         unsigned long i;
 221         struct ttm_backend *be;
 222         int ret;
 223
 224         if (ttm->state != tt_unpopulated)
 225                 return 0;
 226
 227         if (unlikely(ttm->page_flags & TTM_PAGE_FLAG_SWAPPED)) {
 228                 ret = ttm_tt_swapin(ttm);
 229                 if (unlikely(ret != 0))
 230                         return ret;
 231         }
 232
 233         be = ttm->be;
 234
 235         for (i = 0; i < ttm->num_pages; ++i) {
 236                 page = __ttm_tt_get_page(ttm, i);
 237                 if (!page)
 238                         return -ENOMEM;
 239         }
 240
 241         be->func->populate(be, ttm->num_pages, ttm->pages,
 242                            ttm->dummy_read_page);
 243         ttm->state = tt_unbound;
 244         return 0;
 245 }
 246
 247 #ifdef CONFIG_X86
 248 static inline int ttm_tt_set_page_caching(struct page *p,
 249                                           enum ttm_caching_state c_state)
 250 {
 251         if (PageHighMem(p))
 252                 return 0;
 253
 254         switch (c_state) {
 255         case tt_cached:
 256                 return set_pages_wb(p, 1);
 257         case tt_wc:
 258             return set_memory_wc((unsigned long) page_address(p), 1);
 259         default:
 260                 return set_pages_uc(p, 1);
 261         }
 262 }
 263 #else /* CONFIG_X86 */
 264 static inline int ttm_tt_set_page_caching(struct page *p,
 265                                           enum ttm_caching_state c_state)
 266 {
 267         return 0;
 268 }
 269 #endif /* CONFIG_X86 */
 270
 271 /*
 272  * Change caching policy for the linear kernel map
 273  * for range of pages in a ttm.
 274  */
 275
 276 static int ttm_tt_set_caching(struct ttm_tt *ttm,
 277                               enum ttm_caching_state c_state)
 278 {
 279         int i, j;
 280         struct page *cur_page;
 281         int ret;
 282
 283         if (ttm->caching_state == c_state)
 284                 return 0;
 285
 286         if (c_state != tt_cached) {
 287                 ret = ttm_tt_populate(ttm);
 288                 if (unlikely(ret != 0))
 289                         return ret;
 290         }
 291
 292         if (ttm->caching_state == tt_cached)
 293                 ttm_tt_cache_flush(ttm->pages, ttm->num_pages);
 294
 295         for (i = 0; i < ttm->num_pages; ++i) {
 296                 cur_page = ttm->pages[i];
 297                 if (likely(cur_page != NULL)) {
 298                         ret = ttm_tt_set_page_caching(cur_page, c_state);
 299                         if (unlikely(ret != 0))
 300                                 goto out_err;
 301                 }
 302         }
 303
 304         ttm->caching_state = c_state;
 305
 306         return 0;
 307
 308 out_err:
 309         for (j = 0; j < i; ++j) {
 310                 cur_page = ttm->pages[j];
 311                 if (likely(cur_page != NULL)) {
 312                         (void)ttm_tt_set_page_caching(cur_page,
 313                                                       ttm->caching_state);
 314                 }
 315         }
 316
 317         return ret;
 318 }
 319
 320 int ttm_tt_set_placement_caching(struct ttm_tt *ttm, uint32_t placement)
 321 {
 322         enum ttm_caching_state state;
 323
 324         if (placement & TTM_PL_FLAG_WC)
 325                 state = tt_wc;
 326         else if (placement & TTM_PL_FLAG_UNCACHED)
 327                 state = tt_uncached;
 328         else
 329                 state = tt_cached;
 330
 331         return ttm_tt_set_caching(ttm, state);
 332 }
 333
 334 static void ttm_tt_free_alloced_pages(struct ttm_tt *ttm)
 335 {
 336         int i;
 337         struct page *cur_page;
 338         struct ttm_backend *be = ttm->be;
 339
 340         if (be)
 341                 be->func->clear(be);
 342         (void)ttm_tt_set_caching(ttm, tt_cached);
 343         for (i = 0; i < ttm->num_pages; ++i) {
 344                 cur_page = ttm->pages[i];
 345                 ttm->pages[i] = NULL;
 346                 if (cur_page) {
 347                         if (page_count(cur_page) != 1)
 348                                 printk(KERN_ERR TTM_PFX
 349                                        "Erroneous page count. "
 350                                        "Leaking pages.\n");
 351                         ttm_mem_global_free_page(ttm->bdev->mem_glob,
 352                                                  cur_page);
 353                         __free_page(cur_page);
 354                 }
 355         }
 356         ttm->state = tt_unpopulated;
 357         ttm->first_himem_page = ttm->num_pages;
 358         ttm->last_lomem_page = -1;
 359 }
 360
 361 void ttm_tt_destroy(struct ttm_tt *ttm)
 362 {
 363         struct ttm_backend *be;
 364
 365         if (unlikely(ttm == NULL))
 366                 return;
 367
 368         be = ttm->be;
 369         if (likely(be != NULL)) {
 370                 be->func->destroy(be);
 371                 ttm->be = NULL;
 372         }
 373
 374         if (likely(ttm->pages != NULL)) {
 375                 if (ttm->page_flags & TTM_PAGE_FLAG_USER)
 376                         ttm_tt_free_user_pages(ttm);
 377                 else
 378                         ttm_tt_free_alloced_pages(ttm);
 379
 380                 ttm_tt_free_page_directory(ttm);
 381         }
 382
 383         if (!(ttm->page_flags & TTM_PAGE_FLAG_PERSISTANT_SWAP) &&
 384             ttm->swap_storage)
 385                 fput(ttm->swap_storage);
 386
 387         kfree(ttm);
 388 }
 389
 390 int ttm_tt_set_user(struct ttm_tt *ttm,
 391                     struct task_struct *tsk,
 392                     unsigned long start, unsigned long num_pages)
 393 {
 394         struct mm_struct *mm = tsk->mm;
 395         int ret;
 396         int write = (ttm->page_flags & TTM_PAGE_FLAG_WRITE) != 0;
 397         struct ttm_mem_global *mem_glob = ttm->bdev->mem_glob;
 398
 399         BUG_ON(num_pages != ttm->num_pages);
 400         BUG_ON((ttm->page_flags & TTM_PAGE_FLAG_USER) == 0);
 401
 402         /**
 403          * Account user pages as lowmem pages for now.
 404          */
 405
 406         ret = ttm_mem_global_alloc(mem_glob, num_pages * PAGE_SIZE,
 407                                    false, false);
 408         if (unlikely(ret != 0))
 409                 return ret;
 410
 411         down_read(&mm->mmap_sem);
 412         ret = get_user_pages(tsk, mm, start, num_pages,
 413                              write, 0, ttm->pages, NULL);
 414         up_read(&mm->mmap_sem);
 415
 416         if (ret != num_pages && write) {
 417                 ttm_tt_free_user_pages(ttm);
 418                 ttm_mem_global_free(mem_glob, num_pages * PAGE_SIZE);
 419                 return -ENOMEM;
 420         }
 421
 422         ttm->tsk = tsk;
 423         ttm->start = start;
 424         ttm->state = tt_unbound;
 425
 426         return 0;
 427 }
 428
 429 struct ttm_tt *ttm_tt_create(struct ttm_bo_device *bdev, unsigned long size,
 430                              uint32_t page_flags, struct page *dummy_read_page)
 431 {
 432         struct ttm_bo_driver *bo_driver = bdev->driver;
 433         struct ttm_tt *ttm;
 434
 435         if (!bo_driver)
 436                 return NULL;
 437
 438         ttm = kzalloc(sizeof(*ttm), GFP_KERNEL);
 439         if (!ttm)
 440                 return NULL;
 441
 442         ttm->bdev = bdev;
 443
 444         ttm->num_pages = (size + PAGE_SIZE - 1) >> PAGE_SHIFT;
 445         ttm->first_himem_page = ttm->num_pages;
 446         ttm->last_lomem_page = -1;
 447         ttm->caching_state = tt_cached;
 448         ttm->page_flags = page_flags;
 449
 450         ttm->dummy_read_page = dummy_read_page;
 451
 452         ttm_tt_alloc_page_directory(ttm);
 453         if (!ttm->pages) {
 454                 ttm_tt_destroy(ttm);
 455                 printk(KERN_ERR TTM_PFX "Failed allocating page table\n");
 456                 return NULL;
 457         }
 458         ttm->be = bo_driver->create_ttm_backend_entry(bdev);
 459         if (!ttm->be) {
 460                 ttm_tt_destroy(ttm);
 461                 printk(KERN_ERR TTM_PFX "Failed creating ttm backend entry\n");
 462                 return NULL;
 463         }
 464         ttm->state = tt_unpopulated;
 465         return ttm;
 466 }
 467
 468 void ttm_tt_unbind(struct ttm_tt *ttm)
 469 {
 470         int ret;
 471         struct ttm_backend *be = ttm->be;
 472
 473         if (ttm->state == tt_bound) {
 474                 ret = be->func->unbind(be);
 475                 BUG_ON(ret);
 476                 ttm->state = tt_unbound;
 477         }
 478 }
 479
 480 int ttm_tt_bind(struct ttm_tt *ttm, struct ttm_mem_reg *bo_mem)
 481 {
 482         int ret = 0;
 483         struct ttm_backend *be;
 484
 485         if (!ttm)
 486                 return -EINVAL;
 487
 488         if (ttm->state == tt_bound)
 489                 return 0;
 490
 491         be = ttm->be;
 492
 493         ret = ttm_tt_populate(ttm);
 494         if (ret)
 495                 return ret;
 496
 497         ret = be->func->bind(be, bo_mem);
 498         if (ret) {
 499                 printk(KERN_ERR TTM_PFX "Couldn't bind backend.\n");
 500                 return ret;
 501         }
 502
 503         ttm->state = tt_bound;
 504
 505         if (ttm->page_flags & TTM_PAGE_FLAG_USER)
 506                 ttm->page_flags |= TTM_PAGE_FLAG_USER_DIRTY;
 507         return 0;
 508 }
 509 EXPORT_SYMBOL(ttm_tt_bind);
 510
 511 static int ttm_tt_swapin(struct ttm_tt *ttm)
 512 {
 513         struct address_space *swap_space;
 514         struct file *swap_storage;
 515         struct page *from_page;
 516         struct page *to_page;
 517         void *from_virtual;
 518         void *to_virtual;
 519         int i;
 520         int ret;
 521
 522         if (ttm->page_flags & TTM_PAGE_FLAG_USER) {
 523                 ret = ttm_tt_set_user(ttm, ttm->tsk, ttm->start,
 524                                       ttm->num_pages);
 525                 if (unlikely(ret != 0))
 526                         return ret;
 527
 528                 ttm->page_flags &= ~TTM_PAGE_FLAG_SWAPPED;
 529                 return 0;
 530         }
 531
 532         swap_storage = ttm->swap_storage;
 533         BUG_ON(swap_storage == NULL);
 534
 535         swap_space = swap_storage->f_path.dentry->d_inode->i_mapping;
 536
 537         for (i = 0; i < ttm->num_pages; ++i) {
 538                 from_page = read_mapping_page(swap_space, i, NULL);
 539                 if (IS_ERR(from_page))
 540                         goto out_err;
 541                 to_page = __ttm_tt_get_page(ttm, i);
 542                 if (unlikely(to_page == NULL))
 543                         goto out_err;
 544
 545                 preempt_disable();
 546                 from_virtual = kmap_atomic(from_page, KM_USER0);
 547                 to_virtual = kmap_atomic(to_page, KM_USER1);
 548                 memcpy(to_virtual, from_virtual, PAGE_SIZE);
 549                 kunmap_atomic(to_virtual, KM_USER1);
 550                 kunmap_atomic(from_virtual, KM_USER0);
 551                 preempt_enable();
 552                 page_cache_release(from_page);
 553         }
 554
 555         if (!(ttm->page_flags & TTM_PAGE_FLAG_PERSISTANT_SWAP))
 556                 fput(swap_storage);
 557         ttm->swap_storage = NULL;
 558         ttm->page_flags &= ~TTM_PAGE_FLAG_SWAPPED;
 559
 560         return 0;
 561 out_err:
 562         ttm_tt_free_alloced_pages(ttm);
 563         return -ENOMEM;
 564 }
 565
 566 int ttm_tt_swapout(struct ttm_tt *ttm, struct file *persistant_swap_storage)
 567 {
 568         struct address_space *swap_space;
 569         struct file *swap_storage;
 570         struct page *from_page;
 571         struct page *to_page;
 572         void *from_virtual;
 573         void *to_virtual;
 574         int i;
 575
 576         BUG_ON(ttm->state != tt_unbound && ttm->state != tt_unpopulated);
 577         BUG_ON(ttm->caching_state != tt_cached);
 578
 579         /*
 580          * For user buffers, just unpin the pages, as there should be
 581          * vma references.
 582          */
 583
 584         if (ttm->page_flags & TTM_PAGE_FLAG_USER) {
 585                 ttm_tt_free_user_pages(ttm);
 586                 ttm->page_flags |= TTM_PAGE_FLAG_SWAPPED;
 587                 ttm->swap_storage = NULL;
 588                 return 0;
 589         }
 590
 591         if (!persistant_swap_storage) {
 592                 swap_storage = shmem_file_setup("ttm swap",
 593                                                 ttm->num_pages << PAGE_SHIFT,
 594                                                 0);
 595                 if (unlikely(IS_ERR(swap_storage))) {
 596                         printk(KERN_ERR "Failed allocating swap storage.\n");
 597                         return -ENOMEM;
 598                 }
 599         } else
 600                 swap_storage = persistant_swap_storage;
 601
 602         swap_space = swap_storage->f_path.dentry->d_inode->i_mapping;
 603
 604         for (i = 0; i < ttm->num_pages; ++i) {
 605                 from_page = ttm->pages[i];
 606                 if (unlikely(from_page == NULL))
 607                         continue;
 608                 to_page = read_mapping_page(swap_space, i, NULL);
 609                 if (unlikely(to_page == NULL))
 610                         goto out_err;
 611
 612                 preempt_disable();
 613                 from_virtual = kmap_atomic(from_page, KM_USER0);
 614                 to_virtual = kmap_atomic(to_page, KM_USER1);
 615                 memcpy(to_virtual, from_virtual, PAGE_SIZE);
 616                 kunmap_atomic(to_virtual, KM_USER1);
 617                 kunmap_atomic(from_virtual, KM_USER0);
 618                 preempt_enable();
 619                 set_page_dirty(to_page);
 620                 mark_page_accessed(to_page);
 621                 page_cache_release(to_page);
 622         }
 623
 624         ttm_tt_free_alloced_pages(ttm);
 625         ttm->swap_storage = swap_storage;
 626         ttm->page_flags |= TTM_PAGE_FLAG_SWAPPED;
 627         if (persistant_swap_storage)
 628                 ttm->page_flags |= TTM_PAGE_FLAG_PERSISTANT_SWAP;
 629
 630         return 0;
 631 out_err:
 632         if (!persistant_swap_storage)
 633                 fput(swap_storage);
 634
 635         return -ENOMEM;
 636 }