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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 "drm_cache.h"
  38 #include "ttm/ttm_module.h"
  39 #include "ttm/ttm_bo_driver.h"
  40 #include "ttm/ttm_placement.h"
  41
  42 static int ttm_tt_swapin(struct ttm_tt *ttm);
  43
  44 /**
  45  * Allocates storage for pointers to the pages that back the ttm.
  46  *
  47  * Uses kmalloc if possible. Otherwise falls back to vmalloc.
  48  */
  49 static void ttm_tt_alloc_page_directory(struct ttm_tt *ttm)
  50 {
  51         unsigned long size = ttm->num_pages * sizeof(*ttm->pages);
  52         ttm->pages = NULL;
  53
  54         if (size <= PAGE_SIZE)
  55                 ttm->pages = kzalloc(size, GFP_KERNEL);
  56
  57         if (!ttm->pages) {
  58                 ttm->pages = vmalloc_user(size);
  59                 if (ttm->pages)
  60                         ttm->page_flags |= TTM_PAGE_FLAG_VMALLOC;
  61         }
  62 }
  63
  64 static void ttm_tt_free_page_directory(struct ttm_tt *ttm)
  65 {
  66         if (ttm->page_flags & TTM_PAGE_FLAG_VMALLOC) {
  67                 vfree(ttm->pages);
  68                 ttm->page_flags &= ~TTM_PAGE_FLAG_VMALLOC;
  69         } else {
  70                 kfree(ttm->pages);
  71         }
  72         ttm->pages = NULL;
  73 }
  74
  75 static struct page *ttm_tt_alloc_page(unsigned page_flags)
  76 {
  77         gfp_t gfp_flags = GFP_USER;
  78
  79         if (page_flags & TTM_PAGE_FLAG_ZERO_ALLOC)
  80                 gfp_flags |= __GFP_ZERO;
  81
  82         if (page_flags & TTM_PAGE_FLAG_DMA32)
  83                 gfp_flags |= __GFP_DMA32;
  84         else
  85                 gfp_flags |= __GFP_HIGHMEM;
  86
  87         return alloc_page(gfp_flags);
  88 }
  89
  90 static void ttm_tt_free_user_pages(struct ttm_tt *ttm)
  91 {
  92         int write;
  93         int dirty;
  94         struct page *page;
  95         int i;
  96         struct ttm_backend *be = ttm->be;
  97
  98         BUG_ON(!(ttm->page_flags & TTM_PAGE_FLAG_USER));
  99         write = ((ttm->page_flags & TTM_PAGE_FLAG_WRITE) != 0);
 100         dirty = ((ttm->page_flags & TTM_PAGE_FLAG_USER_DIRTY) != 0);
 101
 102         if (be)
 103                 be->func->clear(be);
 104
 105         for (i = 0; i < ttm->num_pages; ++i) {
 106                 page = ttm->pages[i];
 107                 if (page == NULL)
 108                         continue;
 109
 110                 if (page == ttm->dummy_read_page) {
 111                         BUG_ON(write);
 112                         continue;
 113                 }
 114
 115                 if (write && dirty && !PageReserved(page))
 116                         set_page_dirty_lock(page);
 117
 118                 ttm->pages[i] = NULL;
 119                 ttm_mem_global_free(ttm->glob->mem_glob, PAGE_SIZE);
 120                 put_page(page);
 121         }
 122         ttm->state = tt_unpopulated;
 123         ttm->first_himem_page = ttm->num_pages;
 124         ttm->last_lomem_page = -1;
 125 }
 126
 127 static struct page *__ttm_tt_get_page(struct ttm_tt *ttm, int index)
 128 {
 129         struct page *p;
 130         struct ttm_mem_global *mem_glob = ttm->glob->mem_glob;
 131         int ret;
 132
 133         while (NULL == (p = ttm->pages[index])) {
 134                 p = ttm_tt_alloc_page(ttm->page_flags);
 135
 136                 if (!p)
 137                         return NULL;
 138
 139                 ret = ttm_mem_global_alloc_page(mem_glob, p, false, false);
 140                 if (unlikely(ret != 0))
 141                         goto out_err;
 142
 143                 if (PageHighMem(p))
 144                         ttm->pages[--ttm->first_himem_page] = p;
 145                 else
 146                         ttm->pages[++ttm->last_lomem_page] = p;
 147         }
 148         return p;
 149 out_err:
 150         put_page(p);
 151         return NULL;
 152 }
 153
 154 struct page *ttm_tt_get_page(struct ttm_tt *ttm, int index)
 155 {
 156         int ret;
 157
 158         if (unlikely(ttm->page_flags & TTM_PAGE_FLAG_SWAPPED)) {
 159                 ret = ttm_tt_swapin(ttm);
 160                 if (unlikely(ret != 0))
 161                         return NULL;
 162         }
 163         return __ttm_tt_get_page(ttm, index);
 164 }
 165
 166 int ttm_tt_populate(struct ttm_tt *ttm)
 167 {
 168         struct page *page;
 169         unsigned long i;
 170         struct ttm_backend *be;
 171         int ret;
 172
 173         if (ttm->state != tt_unpopulated)
 174                 return 0;
 175
 176         if (unlikely(ttm->page_flags & TTM_PAGE_FLAG_SWAPPED)) {
 177                 ret = ttm_tt_swapin(ttm);
 178                 if (unlikely(ret != 0))
 179                         return ret;
 180         }
 181
 182         be = ttm->be;
 183
 184         for (i = 0; i < ttm->num_pages; ++i) {
 185                 page = __ttm_tt_get_page(ttm, i);
 186                 if (!page)
 187                         return -ENOMEM;
 188         }
 189
 190         be->func->populate(be, ttm->num_pages, ttm->pages,
 191                            ttm->dummy_read_page);
 192         ttm->state = tt_unbound;
 193         return 0;
 194 }
 195
 196 #ifdef CONFIG_X86
 197 static inline int ttm_tt_set_page_caching(struct page *p,
 198                                           enum ttm_caching_state c_state)
 199 {
 200         if (PageHighMem(p))
 201                 return 0;
 202
 203         switch (c_state) {
 204         case tt_cached:
 205                 return set_pages_wb(p, 1);
 206         case tt_wc:
 207             return set_memory_wc((unsigned long) page_address(p), 1);
 208         default:
 209                 return set_pages_uc(p, 1);
 210         }
 211 }
 212 #else /* CONFIG_X86 */
 213 static inline int ttm_tt_set_page_caching(struct page *p,
 214                                           enum ttm_caching_state c_state)
 215 {
 216         return 0;
 217 }
 218 #endif /* CONFIG_X86 */
 219
 220 /*
 221  * Change caching policy for the linear kernel map
 222  * for range of pages in a ttm.
 223  */
 224
 225 static int ttm_tt_set_caching(struct ttm_tt *ttm,
 226                               enum ttm_caching_state c_state)
 227 {
 228         int i, j;
 229         struct page *cur_page;
 230         int ret;
 231
 232         if (ttm->caching_state == c_state)
 233                 return 0;
 234
 235         if (c_state != tt_cached) {
 236                 ret = ttm_tt_populate(ttm);
 237                 if (unlikely(ret != 0))
 238                         return ret;
 239         }
 240
 241         if (ttm->caching_state == tt_cached)
 242                 drm_clflush_pages(ttm->pages, ttm->num_pages);
 243
 244         for (i = 0; i < ttm->num_pages; ++i) {
 245                 cur_page = ttm->pages[i];
 246                 if (likely(cur_page != NULL)) {
 247                         ret = ttm_tt_set_page_caching(cur_page, c_state);
 248                         if (unlikely(ret != 0))
 249                                 goto out_err;
 250                 }
 251         }
 252
 253         ttm->caching_state = c_state;
 254
 255         return 0;
 256
 257 out_err:
 258         for (j = 0; j < i; ++j) {
 259                 cur_page = ttm->pages[j];
 260                 if (likely(cur_page != NULL)) {
 261                         (void)ttm_tt_set_page_caching(cur_page,
 262                                                       ttm->caching_state);
 263                 }
 264         }
 265
 266         return ret;
 267 }
 268
 269 int ttm_tt_set_placement_caching(struct ttm_tt *ttm, uint32_t placement)
 270 {
 271         enum ttm_caching_state state;
 272
 273         if (placement & TTM_PL_FLAG_WC)
 274                 state = tt_wc;
 275         else if (placement & TTM_PL_FLAG_UNCACHED)
 276                 state = tt_uncached;
 277         else
 278                 state = tt_cached;
 279
 280         return ttm_tt_set_caching(ttm, state);
 281 }
 282
 283 static void ttm_tt_free_alloced_pages(struct ttm_tt *ttm)
 284 {
 285         int i;
 286         struct page *cur_page;
 287         struct ttm_backend *be = ttm->be;
 288
 289         if (be)
 290                 be->func->clear(be);
 291         (void)ttm_tt_set_caching(ttm, tt_cached);
 292         for (i = 0; i < ttm->num_pages; ++i) {
 293                 cur_page = ttm->pages[i];
 294                 ttm->pages[i] = NULL;
 295                 if (cur_page) {
 296                         if (page_count(cur_page) != 1)
 297                                 printk(KERN_ERR TTM_PFX
 298                                        "Erroneous page count. "
 299                                        "Leaking pages.\n");
 300                         ttm_mem_global_free_page(ttm->glob->mem_glob,
 301                                                  cur_page);
 302                         __free_page(cur_page);
 303                 }
 304         }
 305         ttm->state = tt_unpopulated;
 306         ttm->first_himem_page = ttm->num_pages;
 307         ttm->last_lomem_page = -1;
 308 }
 309
 310 void ttm_tt_destroy(struct ttm_tt *ttm)
 311 {
 312         struct ttm_backend *be;
 313
 314         if (unlikely(ttm == NULL))
 315                 return;
 316
 317         be = ttm->be;
 318         if (likely(be != NULL)) {
 319                 be->func->destroy(be);
 320                 ttm->be = NULL;
 321         }
 322
 323         if (likely(ttm->pages != NULL)) {
 324                 if (ttm->page_flags & TTM_PAGE_FLAG_USER)
 325                         ttm_tt_free_user_pages(ttm);
 326                 else
 327                         ttm_tt_free_alloced_pages(ttm);
 328
 329                 ttm_tt_free_page_directory(ttm);
 330         }
 331
 332         if (!(ttm->page_flags & TTM_PAGE_FLAG_PERSISTANT_SWAP) &&
 333             ttm->swap_storage)
 334                 fput(ttm->swap_storage);
 335
 336         kfree(ttm);
 337 }
 338
 339 int ttm_tt_set_user(struct ttm_tt *ttm,
 340                     struct task_struct *tsk,
 341                     unsigned long start, unsigned long num_pages)
 342 {
 343         struct mm_struct *mm = tsk->mm;
 344         int ret;
 345         int write = (ttm->page_flags & TTM_PAGE_FLAG_WRITE) != 0;
 346         struct ttm_mem_global *mem_glob = ttm->glob->mem_glob;
 347
 348         BUG_ON(num_pages != ttm->num_pages);
 349         BUG_ON((ttm->page_flags & TTM_PAGE_FLAG_USER) == 0);
 350
 351         /**
 352          * Account user pages as lowmem pages for now.
 353          */
 354
 355         ret = ttm_mem_global_alloc(mem_glob, num_pages * PAGE_SIZE,
 356                                    false, false);
 357         if (unlikely(ret != 0))
 358                 return ret;
 359
 360         down_read(&mm->mmap_sem);
 361         ret = get_user_pages(tsk, mm, start, num_pages,
 362                              write, 0, ttm->pages, NULL);
 363         up_read(&mm->mmap_sem);
 364
 365         if (ret != num_pages && write) {
 366                 ttm_tt_free_user_pages(ttm);
 367                 ttm_mem_global_free(mem_glob, num_pages * PAGE_SIZE);
 368                 return -ENOMEM;
 369         }
 370
 371         ttm->tsk = tsk;
 372         ttm->start = start;
 373         ttm->state = tt_unbound;
 374
 375         return 0;
 376 }
 377
 378 struct ttm_tt *ttm_tt_create(struct ttm_bo_device *bdev, unsigned long size,
 379                              uint32_t page_flags, struct page *dummy_read_page)
 380 {
 381         struct ttm_bo_driver *bo_driver = bdev->driver;
 382         struct ttm_tt *ttm;
 383
 384         if (!bo_driver)
 385                 return NULL;
 386
 387         ttm = kzalloc(sizeof(*ttm), GFP_KERNEL);
 388         if (!ttm)
 389                 return NULL;
 390
 391         ttm->glob = bdev->glob;
 392         ttm->num_pages = (size + PAGE_SIZE - 1) >> PAGE_SHIFT;
 393         ttm->first_himem_page = ttm->num_pages;
 394         ttm->last_lomem_page = -1;
 395         ttm->caching_state = tt_cached;
 396         ttm->page_flags = page_flags;
 397
 398         ttm->dummy_read_page = dummy_read_page;
 399
 400         ttm_tt_alloc_page_directory(ttm);
 401         if (!ttm->pages) {
 402                 ttm_tt_destroy(ttm);
 403                 printk(KERN_ERR TTM_PFX "Failed allocating page table\n");
 404                 return NULL;
 405         }
 406         ttm->be = bo_driver->create_ttm_backend_entry(bdev);
 407         if (!ttm->be) {
 408                 ttm_tt_destroy(ttm);
 409                 printk(KERN_ERR TTM_PFX "Failed creating ttm backend entry\n");
 410                 return NULL;
 411         }
 412         ttm->state = tt_unpopulated;
 413         return ttm;
 414 }
 415
 416 void ttm_tt_unbind(struct ttm_tt *ttm)
 417 {
 418         int ret;
 419         struct ttm_backend *be = ttm->be;
 420
 421         if (ttm->state == tt_bound) {
 422                 ret = be->func->unbind(be);
 423                 BUG_ON(ret);
 424                 ttm->state = tt_unbound;
 425         }
 426 }
 427
 428 int ttm_tt_bind(struct ttm_tt *ttm, struct ttm_mem_reg *bo_mem)
 429 {
 430         int ret = 0;
 431         struct ttm_backend *be;
 432
 433         if (!ttm)
 434                 return -EINVAL;
 435
 436         if (ttm->state == tt_bound)
 437                 return 0;
 438
 439         be = ttm->be;
 440
 441         ret = ttm_tt_populate(ttm);
 442         if (ret)
 443                 return ret;
 444
 445         ret = be->func->bind(be, bo_mem);
 446         if (ret) {
 447                 printk(KERN_ERR TTM_PFX "Couldn't bind backend.\n");
 448                 return ret;
 449         }
 450
 451         ttm->state = tt_bound;
 452
 453         if (ttm->page_flags & TTM_PAGE_FLAG_USER)
 454                 ttm->page_flags |= TTM_PAGE_FLAG_USER_DIRTY;
 455         return 0;
 456 }
 457 EXPORT_SYMBOL(ttm_tt_bind);
 458
 459 static int ttm_tt_swapin(struct ttm_tt *ttm)
 460 {
 461         struct address_space *swap_space;
 462         struct file *swap_storage;
 463         struct page *from_page;
 464         struct page *to_page;
 465         void *from_virtual;
 466         void *to_virtual;
 467         int i;
 468         int ret;
 469
 470         if (ttm->page_flags & TTM_PAGE_FLAG_USER) {
 471                 ret = ttm_tt_set_user(ttm, ttm->tsk, ttm->start,
 472                                       ttm->num_pages);
 473                 if (unlikely(ret != 0))
 474                         return ret;
 475
 476                 ttm->page_flags &= ~TTM_PAGE_FLAG_SWAPPED;
 477                 return 0;
 478         }
 479
 480         swap_storage = ttm->swap_storage;
 481         BUG_ON(swap_storage == NULL);
 482
 483         swap_space = swap_storage->f_path.dentry->d_inode->i_mapping;
 484
 485         for (i = 0; i < ttm->num_pages; ++i) {
 486                 from_page = read_mapping_page(swap_space, i, NULL);
 487                 if (IS_ERR(from_page))
 488                         goto out_err;
 489                 to_page = __ttm_tt_get_page(ttm, i);
 490                 if (unlikely(to_page == NULL))
 491                         goto out_err;
 492
 493                 preempt_disable();
 494                 from_virtual = kmap_atomic(from_page, KM_USER0);
 495                 to_virtual = kmap_atomic(to_page, KM_USER1);
 496                 memcpy(to_virtual, from_virtual, PAGE_SIZE);
 497                 kunmap_atomic(to_virtual, KM_USER1);
 498                 kunmap_atomic(from_virtual, KM_USER0);
 499                 preempt_enable();
 500                 page_cache_release(from_page);
 501         }
 502
 503         if (!(ttm->page_flags & TTM_PAGE_FLAG_PERSISTANT_SWAP))
 504                 fput(swap_storage);
 505         ttm->swap_storage = NULL;
 506         ttm->page_flags &= ~TTM_PAGE_FLAG_SWAPPED;
 507
 508         return 0;
 509 out_err:
 510         ttm_tt_free_alloced_pages(ttm);
 511         return -ENOMEM;
 512 }
 513
 514 int ttm_tt_swapout(struct ttm_tt *ttm, struct file *persistant_swap_storage)
 515 {
 516         struct address_space *swap_space;
 517         struct file *swap_storage;
 518         struct page *from_page;
 519         struct page *to_page;
 520         void *from_virtual;
 521         void *to_virtual;
 522         int i;
 523
 524         BUG_ON(ttm->state != tt_unbound && ttm->state != tt_unpopulated);
 525         BUG_ON(ttm->caching_state != tt_cached);
 526
 527         /*
 528          * For user buffers, just unpin the pages, as there should be
 529          * vma references.
 530          */
 531
 532         if (ttm->page_flags & TTM_PAGE_FLAG_USER) {
 533                 ttm_tt_free_user_pages(ttm);
 534                 ttm->page_flags |= TTM_PAGE_FLAG_SWAPPED;
 535                 ttm->swap_storage = NULL;
 536                 return 0;
 537         }
 538
 539         if (!persistant_swap_storage) {
 540                 swap_storage = shmem_file_setup("ttm swap",
 541                                                 ttm->num_pages << PAGE_SHIFT,
 542                                                 0);
 543                 if (unlikely(IS_ERR(swap_storage))) {
 544                         printk(KERN_ERR "Failed allocating swap storage.\n");
 545                         return -ENOMEM;
 546                 }
 547         } else
 548                 swap_storage = persistant_swap_storage;
 549
 550         swap_space = swap_storage->f_path.dentry->d_inode->i_mapping;
 551
 552         for (i = 0; i < ttm->num_pages; ++i) {
 553                 from_page = ttm->pages[i];
 554                 if (unlikely(from_page == NULL))
 555                         continue;
 556                 to_page = read_mapping_page(swap_space, i, NULL);
 557                 if (unlikely(to_page == NULL))
 558                         goto out_err;
 559
 560                 preempt_disable();
 561                 from_virtual = kmap_atomic(from_page, KM_USER0);
 562                 to_virtual = kmap_atomic(to_page, KM_USER1);
 563                 memcpy(to_virtual, from_virtual, PAGE_SIZE);
 564                 kunmap_atomic(to_virtual, KM_USER1);
 565                 kunmap_atomic(from_virtual, KM_USER0);
 566                 preempt_enable();
 567                 set_page_dirty(to_page);
 568                 mark_page_accessed(to_page);
 569                 page_cache_release(to_page);
 570         }
 571
 572         ttm_tt_free_alloced_pages(ttm);
 573         ttm->swap_storage = swap_storage;
 574         ttm->page_flags |= TTM_PAGE_FLAG_SWAPPED;
 575         if (persistant_swap_storage)
 576                 ttm->page_flags |= TTM_PAGE_FLAG_PERSISTANT_SWAP;
 577
 578         return 0;
 579 out_err:
 580         if (!persistant_swap_storage)
 581                 fput(swap_storage);
 582
 583         return -ENOMEM;
 584 }