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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->glob->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_mem_global *mem_glob = ttm->glob->mem_glob;
 181         int ret;
 182
 183         while (NULL == (p = ttm->pages[index])) {
 184                 p = ttm_tt_alloc_page(ttm->page_flags);
 185
 186                 if (!p)
 187                         return NULL;
 188
 189                 ret = ttm_mem_global_alloc_page(mem_glob, p, false, false);
 190                 if (unlikely(ret != 0))
 191                         goto out_err;
 192
 193                 if (PageHighMem(p))
 194                         ttm->pages[--ttm->first_himem_page] = p;
 195                 else
 196                         ttm->pages[++ttm->last_lomem_page] = p;
 197         }
 198         return p;
 199 out_err:
 200         put_page(p);
 201         return NULL;
 202 }
 203
 204 struct page *ttm_tt_get_page(struct ttm_tt *ttm, int index)
 205 {
 206         int ret;
 207
 208         if (unlikely(ttm->page_flags & TTM_PAGE_FLAG_SWAPPED)) {
 209                 ret = ttm_tt_swapin(ttm);
 210                 if (unlikely(ret != 0))
 211                         return NULL;
 212         }
 213         return __ttm_tt_get_page(ttm, index);
 214 }
 215
 216 int ttm_tt_populate(struct ttm_tt *ttm)
 217 {
 218         struct page *page;
 219         unsigned long i;
 220         struct ttm_backend *be;
 221         int ret;
 222
 223         if (ttm->state != tt_unpopulated)
 224                 return 0;
 225
 226         if (unlikely(ttm->page_flags & TTM_PAGE_FLAG_SWAPPED)) {
 227                 ret = ttm_tt_swapin(ttm);
 228                 if (unlikely(ret != 0))
 229                         return ret;
 230         }
 231
 232         be = ttm->be;
 233
 234         for (i = 0; i < ttm->num_pages; ++i) {
 235                 page = __ttm_tt_get_page(ttm, i);
 236                 if (!page)
 237                         return -ENOMEM;
 238         }
 239
 240         be->func->populate(be, ttm->num_pages, ttm->pages,
 241                            ttm->dummy_read_page);
 242         ttm->state = tt_unbound;
 243         return 0;
 244 }
 245
 246 #ifdef CONFIG_X86
 247 static inline int ttm_tt_set_page_caching(struct page *p,
 248                                           enum ttm_caching_state c_state)
 249 {
 250         if (PageHighMem(p))
 251                 return 0;
 252
 253         switch (c_state) {
 254         case tt_cached:
 255                 return set_pages_wb(p, 1);
 256         case tt_wc:
 257             return set_memory_wc((unsigned long) page_address(p), 1);
 258         default:
 259                 return set_pages_uc(p, 1);
 260         }
 261 }
 262 #else /* CONFIG_X86 */
 263 static inline int ttm_tt_set_page_caching(struct page *p,
 264                                           enum ttm_caching_state c_state)
 265 {
 266         return 0;
 267 }
 268 #endif /* CONFIG_X86 */
 269
 270 /*
 271  * Change caching policy for the linear kernel map
 272  * for range of pages in a ttm.
 273  */
 274
 275 static int ttm_tt_set_caching(struct ttm_tt *ttm,
 276                               enum ttm_caching_state c_state)
 277 {
 278         int i, j;
 279         struct page *cur_page;
 280         int ret;
 281
 282         if (ttm->caching_state == c_state)
 283                 return 0;
 284
 285         if (c_state != tt_cached) {
 286                 ret = ttm_tt_populate(ttm);
 287                 if (unlikely(ret != 0))
 288                         return ret;
 289         }
 290
 291         if (ttm->caching_state == tt_cached)
 292                 ttm_tt_cache_flush(ttm->pages, ttm->num_pages);
 293
 294         for (i = 0; i < ttm->num_pages; ++i) {
 295                 cur_page = ttm->pages[i];
 296                 if (likely(cur_page != NULL)) {
 297                         ret = ttm_tt_set_page_caching(cur_page, c_state);
 298                         if (unlikely(ret != 0))
 299                                 goto out_err;
 300                 }
 301         }
 302
 303         ttm->caching_state = c_state;
 304
 305         return 0;
 306
 307 out_err:
 308         for (j = 0; j < i; ++j) {
 309                 cur_page = ttm->pages[j];
 310                 if (likely(cur_page != NULL)) {
 311                         (void)ttm_tt_set_page_caching(cur_page,
 312                                                       ttm->caching_state);
 313                 }
 314         }
 315
 316         return ret;
 317 }
 318
 319 int ttm_tt_set_placement_caching(struct ttm_tt *ttm, uint32_t placement)
 320 {
 321         enum ttm_caching_state state;
 322
 323         if (placement & TTM_PL_FLAG_WC)
 324                 state = tt_wc;
 325         else if (placement & TTM_PL_FLAG_UNCACHED)
 326                 state = tt_uncached;
 327         else
 328                 state = tt_cached;
 329
 330         return ttm_tt_set_caching(ttm, state);
 331 }
 332
 333 static void ttm_tt_free_alloced_pages(struct ttm_tt *ttm)
 334 {
 335         int i;
 336         struct page *cur_page;
 337         struct ttm_backend *be = ttm->be;
 338
 339         if (be)
 340                 be->func->clear(be);
 341         (void)ttm_tt_set_caching(ttm, tt_cached);
 342         for (i = 0; i < ttm->num_pages; ++i) {
 343                 cur_page = ttm->pages[i];
 344                 ttm->pages[i] = NULL;
 345                 if (cur_page) {
 346                         if (page_count(cur_page) != 1)
 347                                 printk(KERN_ERR TTM_PFX
 348                                        "Erroneous page count. "
 349                                        "Leaking pages.\n");
 350                         ttm_mem_global_free_page(ttm->glob->mem_glob,
 351                                                  cur_page);
 352                         __free_page(cur_page);
 353                 }
 354         }
 355         ttm->state = tt_unpopulated;
 356         ttm->first_himem_page = ttm->num_pages;
 357         ttm->last_lomem_page = -1;
 358 }
 359
 360 void ttm_tt_destroy(struct ttm_tt *ttm)
 361 {
 362         struct ttm_backend *be;
 363
 364         if (unlikely(ttm == NULL))
 365                 return;
 366
 367         be = ttm->be;
 368         if (likely(be != NULL)) {
 369                 be->func->destroy(be);
 370                 ttm->be = NULL;
 371         }
 372
 373         if (likely(ttm->pages != NULL)) {
 374                 if (ttm->page_flags & TTM_PAGE_FLAG_USER)
 375                         ttm_tt_free_user_pages(ttm);
 376                 else
 377                         ttm_tt_free_alloced_pages(ttm);
 378
 379                 ttm_tt_free_page_directory(ttm);
 380         }
 381
 382         if (!(ttm->page_flags & TTM_PAGE_FLAG_PERSISTANT_SWAP) &&
 383             ttm->swap_storage)
 384                 fput(ttm->swap_storage);
 385
 386         kfree(ttm);
 387 }
 388
 389 int ttm_tt_set_user(struct ttm_tt *ttm,
 390                     struct task_struct *tsk,
 391                     unsigned long start, unsigned long num_pages)
 392 {
 393         struct mm_struct *mm = tsk->mm;
 394         int ret;
 395         int write = (ttm->page_flags & TTM_PAGE_FLAG_WRITE) != 0;
 396         struct ttm_mem_global *mem_glob = ttm->glob->mem_glob;
 397
 398         BUG_ON(num_pages != ttm->num_pages);
 399         BUG_ON((ttm->page_flags & TTM_PAGE_FLAG_USER) == 0);
 400
 401         /**
 402          * Account user pages as lowmem pages for now.
 403          */
 404
 405         ret = ttm_mem_global_alloc(mem_glob, num_pages * PAGE_SIZE,
 406                                    false, false);
 407         if (unlikely(ret != 0))
 408                 return ret;
 409
 410         down_read(&mm->mmap_sem);
 411         ret = get_user_pages(tsk, mm, start, num_pages,
 412                              write, 0, ttm->pages, NULL);
 413         up_read(&mm->mmap_sem);
 414
 415         if (ret != num_pages && write) {
 416                 ttm_tt_free_user_pages(ttm);
 417                 ttm_mem_global_free(mem_glob, num_pages * PAGE_SIZE);
 418                 return -ENOMEM;
 419         }
 420
 421         ttm->tsk = tsk;
 422         ttm->start = start;
 423         ttm->state = tt_unbound;
 424
 425         return 0;
 426 }
 427
 428 struct ttm_tt *ttm_tt_create(struct ttm_bo_device *bdev, unsigned long size,
 429                              uint32_t page_flags, struct page *dummy_read_page)
 430 {
 431         struct ttm_bo_driver *bo_driver = bdev->driver;
 432         struct ttm_tt *ttm;
 433
 434         if (!bo_driver)
 435                 return NULL;
 436
 437         ttm = kzalloc(sizeof(*ttm), GFP_KERNEL);
 438         if (!ttm)
 439                 return NULL;
 440
 441         ttm->glob = bdev->glob;
 442         ttm->num_pages = (size + PAGE_SIZE - 1) >> PAGE_SHIFT;
 443         ttm->first_himem_page = ttm->num_pages;
 444         ttm->last_lomem_page = -1;
 445         ttm->caching_state = tt_cached;
 446         ttm->page_flags = page_flags;
 447
 448         ttm->dummy_read_page = dummy_read_page;
 449
 450         ttm_tt_alloc_page_directory(ttm);
 451         if (!ttm->pages) {
 452                 ttm_tt_destroy(ttm);
 453                 printk(KERN_ERR TTM_PFX "Failed allocating page table\n");
 454                 return NULL;
 455         }
 456         ttm->be = bo_driver->create_ttm_backend_entry(bdev);
 457         if (!ttm->be) {
 458                 ttm_tt_destroy(ttm);
 459                 printk(KERN_ERR TTM_PFX "Failed creating ttm backend entry\n");
 460                 return NULL;
 461         }
 462         ttm->state = tt_unpopulated;
 463         return ttm;
 464 }
 465
 466 void ttm_tt_unbind(struct ttm_tt *ttm)
 467 {
 468         int ret;
 469         struct ttm_backend *be = ttm->be;
 470
 471         if (ttm->state == tt_bound) {
 472                 ret = be->func->unbind(be);
 473                 BUG_ON(ret);
 474                 ttm->state = tt_unbound;
 475         }
 476 }
 477
 478 int ttm_tt_bind(struct ttm_tt *ttm, struct ttm_mem_reg *bo_mem)
 479 {
 480         int ret = 0;
 481         struct ttm_backend *be;
 482
 483         if (!ttm)
 484                 return -EINVAL;
 485
 486         if (ttm->state == tt_bound)
 487                 return 0;
 488
 489         be = ttm->be;
 490
 491         ret = ttm_tt_populate(ttm);
 492         if (ret)
 493                 return ret;
 494
 495         ret = be->func->bind(be, bo_mem);
 496         if (ret) {
 497                 printk(KERN_ERR TTM_PFX "Couldn't bind backend.\n");
 498                 return ret;
 499         }
 500
 501         ttm->state = tt_bound;
 502
 503         if (ttm->page_flags & TTM_PAGE_FLAG_USER)
 504                 ttm->page_flags |= TTM_PAGE_FLAG_USER_DIRTY;
 505         return 0;
 506 }
 507 EXPORT_SYMBOL(ttm_tt_bind);
 508
 509 static int ttm_tt_swapin(struct ttm_tt *ttm)
 510 {
 511         struct address_space *swap_space;
 512         struct file *swap_storage;
 513         struct page *from_page;
 514         struct page *to_page;
 515         void *from_virtual;
 516         void *to_virtual;
 517         int i;
 518         int ret;
 519
 520         if (ttm->page_flags & TTM_PAGE_FLAG_USER) {
 521                 ret = ttm_tt_set_user(ttm, ttm->tsk, ttm->start,
 522                                       ttm->num_pages);
 523                 if (unlikely(ret != 0))
 524                         return ret;
 525
 526                 ttm->page_flags &= ~TTM_PAGE_FLAG_SWAPPED;
 527                 return 0;
 528         }
 529
 530         swap_storage = ttm->swap_storage;
 531         BUG_ON(swap_storage == NULL);
 532
 533         swap_space = swap_storage->f_path.dentry->d_inode->i_mapping;
 534
 535         for (i = 0; i < ttm->num_pages; ++i) {
 536                 from_page = read_mapping_page(swap_space, i, NULL);
 537                 if (IS_ERR(from_page))
 538                         goto out_err;
 539                 to_page = __ttm_tt_get_page(ttm, i);
 540                 if (unlikely(to_page == NULL))
 541                         goto out_err;
 542
 543                 preempt_disable();
 544                 from_virtual = kmap_atomic(from_page, KM_USER0);
 545                 to_virtual = kmap_atomic(to_page, KM_USER1);
 546                 memcpy(to_virtual, from_virtual, PAGE_SIZE);
 547                 kunmap_atomic(to_virtual, KM_USER1);
 548                 kunmap_atomic(from_virtual, KM_USER0);
 549                 preempt_enable();
 550                 page_cache_release(from_page);
 551         }
 552
 553         if (!(ttm->page_flags & TTM_PAGE_FLAG_PERSISTANT_SWAP))
 554                 fput(swap_storage);
 555         ttm->swap_storage = NULL;
 556         ttm->page_flags &= ~TTM_PAGE_FLAG_SWAPPED;
 557
 558         return 0;
 559 out_err:
 560         ttm_tt_free_alloced_pages(ttm);
 561         return -ENOMEM;
 562 }
 563
 564 int ttm_tt_swapout(struct ttm_tt *ttm, struct file *persistant_swap_storage)
 565 {
 566         struct address_space *swap_space;
 567         struct file *swap_storage;
 568         struct page *from_page;
 569         struct page *to_page;
 570         void *from_virtual;
 571         void *to_virtual;
 572         int i;
 573
 574         BUG_ON(ttm->state != tt_unbound && ttm->state != tt_unpopulated);
 575         BUG_ON(ttm->caching_state != tt_cached);
 576
 577         /*
 578          * For user buffers, just unpin the pages, as there should be
 579          * vma references.
 580          */
 581
 582         if (ttm->page_flags & TTM_PAGE_FLAG_USER) {
 583                 ttm_tt_free_user_pages(ttm);
 584                 ttm->page_flags |= TTM_PAGE_FLAG_SWAPPED;
 585                 ttm->swap_storage = NULL;
 586                 return 0;
 587         }
 588
 589         if (!persistant_swap_storage) {
 590                 swap_storage = shmem_file_setup("ttm swap",
 591                                                 ttm->num_pages << PAGE_SHIFT,
 592                                                 0);
 593                 if (unlikely(IS_ERR(swap_storage))) {
 594                         printk(KERN_ERR "Failed allocating swap storage.\n");
 595                         return -ENOMEM;
 596                 }
 597         } else
 598                 swap_storage = persistant_swap_storage;
 599
 600         swap_space = swap_storage->f_path.dentry->d_inode->i_mapping;
 601
 602         for (i = 0; i < ttm->num_pages; ++i) {
 603                 from_page = ttm->pages[i];
 604                 if (unlikely(from_page == NULL))
 605                         continue;
 606                 to_page = read_mapping_page(swap_space, i, NULL);
 607                 if (unlikely(to_page == NULL))
 608                         goto out_err;
 609
 610                 preempt_disable();
 611                 from_virtual = kmap_atomic(from_page, KM_USER0);
 612                 to_virtual = kmap_atomic(to_page, KM_USER1);
 613                 memcpy(to_virtual, from_virtual, PAGE_SIZE);
 614                 kunmap_atomic(to_virtual, KM_USER1);
 615                 kunmap_atomic(from_virtual, KM_USER0);
 616                 preempt_enable();
 617                 set_page_dirty(to_page);
 618                 mark_page_accessed(to_page);
 619                 page_cache_release(to_page);
 620         }
 621
 622         ttm_tt_free_alloced_pages(ttm);
 623         ttm->swap_storage = swap_storage;
 624         ttm->page_flags |= TTM_PAGE_FLAG_SWAPPED;
 625         if (persistant_swap_storage)
 626                 ttm->page_flags |= TTM_PAGE_FLAG_PERSISTANT_SWAP;
 627
 628         return 0;
 629 out_err:
 630         if (!persistant_swap_storage)
 631                 fput(swap_storage);
 632
 633         return -ENOMEM;
 634 }