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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 <linux/slab.h>
  38 #include "drm_cache.h"
  39 #include "ttm/ttm_module.h"
  40 #include "ttm/ttm_bo_driver.h"
  41 #include "ttm/ttm_placement.h"
  42
  43 static int ttm_tt_swapin(struct ttm_tt *ttm);
  44
  45 /**
  46  * Allocates storage for pointers to the pages that back the ttm.
  47  *
  48  * Uses kmalloc if possible. Otherwise falls back to vmalloc.
  49  */
  50 static void ttm_tt_alloc_page_directory(struct ttm_tt *ttm)
  51 {
  52         unsigned long size = ttm->num_pages * sizeof(*ttm->pages);
  53         ttm->pages = NULL;
  54
  55         if (size <= PAGE_SIZE)
  56                 ttm->pages = kzalloc(size, GFP_KERNEL);
  57
  58         if (!ttm->pages) {
  59                 ttm->pages = vmalloc_user(size);
  60                 if (ttm->pages)
  61                         ttm->page_flags |= TTM_PAGE_FLAG_VMALLOC;
  62         }
  63 }
  64
  65 static void ttm_tt_free_page_directory(struct ttm_tt *ttm)
  66 {
  67         if (ttm->page_flags & TTM_PAGE_FLAG_VMALLOC) {
  68                 vfree(ttm->pages);
  69                 ttm->page_flags &= ~TTM_PAGE_FLAG_VMALLOC;
  70         } else {
  71                 kfree(ttm->pages);
  72         }
  73         ttm->pages = NULL;
  74 }
  75
  76 static struct page *ttm_tt_alloc_page(unsigned page_flags)
  77 {
  78         gfp_t gfp_flags = GFP_USER;
  79
  80         if (page_flags & TTM_PAGE_FLAG_ZERO_ALLOC)
  81                 gfp_flags |= __GFP_ZERO;
  82
  83         if (page_flags & TTM_PAGE_FLAG_DMA32)
  84                 gfp_flags |= __GFP_DMA32;
  85         else
  86                 gfp_flags |= __GFP_HIGHMEM;
  87
  88         return alloc_page(gfp_flags);
  89 }
  90
  91 static void ttm_tt_free_user_pages(struct ttm_tt *ttm)
  92 {
  93         int write;
  94         int dirty;
  95         struct page *page;
  96         int i;
  97         struct ttm_backend *be = ttm->be;
  98
  99         BUG_ON(!(ttm->page_flags & TTM_PAGE_FLAG_USER));
 100         write = ((ttm->page_flags & TTM_PAGE_FLAG_WRITE) != 0);
 101         dirty = ((ttm->page_flags & TTM_PAGE_FLAG_USER_DIRTY) != 0);
 102
 103         if (be)
 104                 be->func->clear(be);
 105
 106         for (i = 0; i < ttm->num_pages; ++i) {
 107                 page = ttm->pages[i];
 108                 if (page == NULL)
 109                         continue;
 110
 111                 if (page == ttm->dummy_read_page) {
 112                         BUG_ON(write);
 113                         continue;
 114                 }
 115
 116                 if (write && dirty && !PageReserved(page))
 117                         set_page_dirty_lock(page);
 118
 119                 ttm->pages[i] = NULL;
 120                 ttm_mem_global_free(ttm->glob->mem_glob, PAGE_SIZE);
 121                 put_page(page);
 122         }
 123         ttm->state = tt_unpopulated;
 124         ttm->first_himem_page = ttm->num_pages;
 125         ttm->last_lomem_page = -1;
 126 }
 127
 128 static struct page *__ttm_tt_get_page(struct ttm_tt *ttm, int index)
 129 {
 130         struct page *p;
 131         struct ttm_mem_global *mem_glob = ttm->glob->mem_glob;
 132         int ret;
 133
 134         while (NULL == (p = ttm->pages[index])) {
 135                 p = ttm_tt_alloc_page(ttm->page_flags);
 136
 137                 if (!p)
 138                         return NULL;
 139
 140                 ret = ttm_mem_global_alloc_page(mem_glob, p, false, false);
 141                 if (unlikely(ret != 0))
 142                         goto out_err;
 143
 144                 if (PageHighMem(p))
 145                         ttm->pages[--ttm->first_himem_page] = p;
 146                 else
 147                         ttm->pages[++ttm->last_lomem_page] = p;
 148         }
 149         return p;
 150 out_err:
 151         put_page(p);
 152         return NULL;
 153 }
 154
 155 struct page *ttm_tt_get_page(struct ttm_tt *ttm, int index)
 156 {
 157         int ret;
 158
 159         if (unlikely(ttm->page_flags & TTM_PAGE_FLAG_SWAPPED)) {
 160                 ret = ttm_tt_swapin(ttm);
 161                 if (unlikely(ret != 0))
 162                         return NULL;
 163         }
 164         return __ttm_tt_get_page(ttm, index);
 165 }
 166
 167 int ttm_tt_populate(struct ttm_tt *ttm)
 168 {
 169         struct page *page;
 170         unsigned long i;
 171         struct ttm_backend *be;
 172         int ret;
 173
 174         if (ttm->state != tt_unpopulated)
 175                 return 0;
 176
 177         if (unlikely(ttm->page_flags & TTM_PAGE_FLAG_SWAPPED)) {
 178                 ret = ttm_tt_swapin(ttm);
 179                 if (unlikely(ret != 0))
 180                         return ret;
 181         }
 182
 183         be = ttm->be;
 184
 185         for (i = 0; i < ttm->num_pages; ++i) {
 186                 page = __ttm_tt_get_page(ttm, i);
 187                 if (!page)
 188                         return -ENOMEM;
 189         }
 190
 191         be->func->populate(be, ttm->num_pages, ttm->pages,
 192                            ttm->dummy_read_page);
 193         ttm->state = tt_unbound;
 194         return 0;
 195 }
 196 EXPORT_SYMBOL(ttm_tt_populate);
 197
 198 #ifdef CONFIG_X86
 199 static inline int ttm_tt_set_page_caching(struct page *p,
 200                                           enum ttm_caching_state c_old,
 201                                           enum ttm_caching_state c_new)
 202 {
 203         int ret = 0;
 204
 205         if (PageHighMem(p))
 206                 return 0;
 207
 208         if (c_old != tt_cached) {
 209                 /* p isn't in the default caching state, set it to
 210                  * writeback first to free its current memtype. */
 211
 212                 ret = set_pages_wb(p, 1);
 213                 if (ret)
 214                         return ret;
 215         }
 216
 217         if (c_new == tt_wc)
 218                 ret = set_memory_wc((unsigned long) page_address(p), 1);
 219         else if (c_new == tt_uncached)
 220                 ret = set_pages_uc(p, 1);
 221
 222         return ret;
 223 }
 224 #else /* CONFIG_X86 */
 225 static inline int ttm_tt_set_page_caching(struct page *p,
 226                                           enum ttm_caching_state c_old,
 227                                           enum ttm_caching_state c_new)
 228 {
 229         return 0;
 230 }
 231 #endif /* CONFIG_X86 */
 232
 233 /*
 234  * Change caching policy for the linear kernel map
 235  * for range of pages in a ttm.
 236  */
 237
 238 static int ttm_tt_set_caching(struct ttm_tt *ttm,
 239                               enum ttm_caching_state c_state)
 240 {
 241         int i, j;
 242         struct page *cur_page;
 243         int ret;
 244
 245         if (ttm->caching_state == c_state)
 246                 return 0;
 247
 248         if (c_state != tt_cached) {
 249                 ret = ttm_tt_populate(ttm);
 250                 if (unlikely(ret != 0))
 251                         return ret;
 252         }
 253
 254         if (ttm->caching_state == tt_cached)
 255                 drm_clflush_pages(ttm->pages, ttm->num_pages);
 256
 257         for (i = 0; i < ttm->num_pages; ++i) {
 258                 cur_page = ttm->pages[i];
 259                 if (likely(cur_page != NULL)) {
 260                         ret = ttm_tt_set_page_caching(cur_page,
 261                                                       ttm->caching_state,
 262                                                       c_state);
 263                         if (unlikely(ret != 0))
 264                                 goto out_err;
 265                 }
 266         }
 267
 268         ttm->caching_state = c_state;
 269
 270         return 0;
 271
 272 out_err:
 273         for (j = 0; j < i; ++j) {
 274                 cur_page = ttm->pages[j];
 275                 if (likely(cur_page != NULL)) {
 276                         (void)ttm_tt_set_page_caching(cur_page, c_state,
 277                                                       ttm->caching_state);
 278                 }
 279         }
 280
 281         return ret;
 282 }
 283
 284 int ttm_tt_set_placement_caching(struct ttm_tt *ttm, uint32_t placement)
 285 {
 286         enum ttm_caching_state state;
 287
 288         if (placement & TTM_PL_FLAG_WC)
 289                 state = tt_wc;
 290         else if (placement & TTM_PL_FLAG_UNCACHED)
 291                 state = tt_uncached;
 292         else
 293                 state = tt_cached;
 294
 295         return ttm_tt_set_caching(ttm, state);
 296 }
 297 EXPORT_SYMBOL(ttm_tt_set_placement_caching);
 298
 299 static void ttm_tt_free_alloced_pages(struct ttm_tt *ttm)
 300 {
 301         int i;
 302         struct page *cur_page;
 303         struct ttm_backend *be = ttm->be;
 304
 305         if (be)
 306                 be->func->clear(be);
 307         (void)ttm_tt_set_caching(ttm, tt_cached);
 308         for (i = 0; i < ttm->num_pages; ++i) {
 309                 cur_page = ttm->pages[i];
 310                 ttm->pages[i] = NULL;
 311                 if (cur_page) {
 312                         if (page_count(cur_page) != 1)
 313                                 printk(KERN_ERR TTM_PFX
 314                                        "Erroneous page count. "
 315                                        "Leaking pages.\n");
 316                         ttm_mem_global_free_page(ttm->glob->mem_glob,
 317                                                  cur_page);
 318                         __free_page(cur_page);
 319                 }
 320         }
 321         ttm->state = tt_unpopulated;
 322         ttm->first_himem_page = ttm->num_pages;
 323         ttm->last_lomem_page = -1;
 324 }
 325
 326 void ttm_tt_destroy(struct ttm_tt *ttm)
 327 {
 328         struct ttm_backend *be;
 329
 330         if (unlikely(ttm == NULL))
 331                 return;
 332
 333         be = ttm->be;
 334         if (likely(be != NULL)) {
 335                 be->func->destroy(be);
 336                 ttm->be = NULL;
 337         }
 338
 339         if (likely(ttm->pages != NULL)) {
 340                 if (ttm->page_flags & TTM_PAGE_FLAG_USER)
 341                         ttm_tt_free_user_pages(ttm);
 342                 else
 343                         ttm_tt_free_alloced_pages(ttm);
 344
 345                 ttm_tt_free_page_directory(ttm);
 346         }
 347
 348         if (!(ttm->page_flags & TTM_PAGE_FLAG_PERSISTANT_SWAP) &&
 349             ttm->swap_storage)
 350                 fput(ttm->swap_storage);
 351
 352         kfree(ttm);
 353 }
 354
 355 int ttm_tt_set_user(struct ttm_tt *ttm,
 356                     struct task_struct *tsk,
 357                     unsigned long start, unsigned long num_pages)
 358 {
 359         struct mm_struct *mm = tsk->mm;
 360         int ret;
 361         int write = (ttm->page_flags & TTM_PAGE_FLAG_WRITE) != 0;
 362         struct ttm_mem_global *mem_glob = ttm->glob->mem_glob;
 363
 364         BUG_ON(num_pages != ttm->num_pages);
 365         BUG_ON((ttm->page_flags & TTM_PAGE_FLAG_USER) == 0);
 366
 367         /**
 368          * Account user pages as lowmem pages for now.
 369          */
 370
 371         ret = ttm_mem_global_alloc(mem_glob, num_pages * PAGE_SIZE,
 372                                    false, false);
 373         if (unlikely(ret != 0))
 374                 return ret;
 375
 376         down_read(&mm->mmap_sem);
 377         ret = get_user_pages(tsk, mm, start, num_pages,
 378                              write, 0, ttm->pages, NULL);
 379         up_read(&mm->mmap_sem);
 380
 381         if (ret != num_pages && write) {
 382                 ttm_tt_free_user_pages(ttm);
 383                 ttm_mem_global_free(mem_glob, num_pages * PAGE_SIZE);
 384                 return -ENOMEM;
 385         }
 386
 387         ttm->tsk = tsk;
 388         ttm->start = start;
 389         ttm->state = tt_unbound;
 390
 391         return 0;
 392 }
 393
 394 struct ttm_tt *ttm_tt_create(struct ttm_bo_device *bdev, unsigned long size,
 395                              uint32_t page_flags, struct page *dummy_read_page)
 396 {
 397         struct ttm_bo_driver *bo_driver = bdev->driver;
 398         struct ttm_tt *ttm;
 399
 400         if (!bo_driver)
 401                 return NULL;
 402
 403         ttm = kzalloc(sizeof(*ttm), GFP_KERNEL);
 404         if (!ttm)
 405                 return NULL;
 406
 407         ttm->glob = bdev->glob;
 408         ttm->num_pages = (size + PAGE_SIZE - 1) >> PAGE_SHIFT;
 409         ttm->first_himem_page = ttm->num_pages;
 410         ttm->last_lomem_page = -1;
 411         ttm->caching_state = tt_cached;
 412         ttm->page_flags = page_flags;
 413
 414         ttm->dummy_read_page = dummy_read_page;
 415
 416         ttm_tt_alloc_page_directory(ttm);
 417         if (!ttm->pages) {
 418                 ttm_tt_destroy(ttm);
 419                 printk(KERN_ERR TTM_PFX "Failed allocating page table\n");
 420                 return NULL;
 421         }
 422         ttm->be = bo_driver->create_ttm_backend_entry(bdev);
 423         if (!ttm->be) {
 424                 ttm_tt_destroy(ttm);
 425                 printk(KERN_ERR TTM_PFX "Failed creating ttm backend entry\n");
 426                 return NULL;
 427         }
 428         ttm->state = tt_unpopulated;
 429         return ttm;
 430 }
 431
 432 void ttm_tt_unbind(struct ttm_tt *ttm)
 433 {
 434         int ret;
 435         struct ttm_backend *be = ttm->be;
 436
 437         if (ttm->state == tt_bound) {
 438                 ret = be->func->unbind(be);
 439                 BUG_ON(ret);
 440                 ttm->state = tt_unbound;
 441         }
 442 }
 443
 444 int ttm_tt_bind(struct ttm_tt *ttm, struct ttm_mem_reg *bo_mem)
 445 {
 446         int ret = 0;
 447         struct ttm_backend *be;
 448
 449         if (!ttm)
 450                 return -EINVAL;
 451
 452         if (ttm->state == tt_bound)
 453                 return 0;
 454
 455         be = ttm->be;
 456
 457         ret = ttm_tt_populate(ttm);
 458         if (ret)
 459                 return ret;
 460
 461         ret = be->func->bind(be, bo_mem);
 462         if (ret) {
 463                 printk(KERN_ERR TTM_PFX "Couldn't bind backend.\n");
 464                 return ret;
 465         }
 466
 467         ttm->state = tt_bound;
 468
 469         if (ttm->page_flags & TTM_PAGE_FLAG_USER)
 470                 ttm->page_flags |= TTM_PAGE_FLAG_USER_DIRTY;
 471         return 0;
 472 }
 473 EXPORT_SYMBOL(ttm_tt_bind);
 474
 475 static int ttm_tt_swapin(struct ttm_tt *ttm)
 476 {
 477         struct address_space *swap_space;
 478         struct file *swap_storage;
 479         struct page *from_page;
 480         struct page *to_page;
 481         void *from_virtual;
 482         void *to_virtual;
 483         int i;
 484         int ret = -ENOMEM;
 485
 486         if (ttm->page_flags & TTM_PAGE_FLAG_USER) {
 487                 ret = ttm_tt_set_user(ttm, ttm->tsk, ttm->start,
 488                                       ttm->num_pages);
 489                 if (unlikely(ret != 0))
 490                         return ret;
 491
 492                 ttm->page_flags &= ~TTM_PAGE_FLAG_SWAPPED;
 493                 return 0;
 494         }
 495
 496         swap_storage = ttm->swap_storage;
 497         BUG_ON(swap_storage == NULL);
 498
 499         swap_space = swap_storage->f_path.dentry->d_inode->i_mapping;
 500
 501         for (i = 0; i < ttm->num_pages; ++i) {
 502                 from_page = read_mapping_page(swap_space, i, NULL);
 503                 if (IS_ERR(from_page)) {
 504                         ret = PTR_ERR(from_page);
 505                         goto out_err;
 506                 }
 507                 to_page = __ttm_tt_get_page(ttm, i);
 508                 if (unlikely(to_page == NULL))
 509                         goto out_err;
 510
 511                 preempt_disable();
 512                 from_virtual = kmap_atomic(from_page, KM_USER0);
 513                 to_virtual = kmap_atomic(to_page, KM_USER1);
 514                 memcpy(to_virtual, from_virtual, PAGE_SIZE);
 515                 kunmap_atomic(to_virtual, KM_USER1);
 516                 kunmap_atomic(from_virtual, KM_USER0);
 517                 preempt_enable();
 518                 page_cache_release(from_page);
 519         }
 520
 521         if (!(ttm->page_flags & TTM_PAGE_FLAG_PERSISTANT_SWAP))
 522                 fput(swap_storage);
 523         ttm->swap_storage = NULL;
 524         ttm->page_flags &= ~TTM_PAGE_FLAG_SWAPPED;
 525
 526         return 0;
 527 out_err:
 528         ttm_tt_free_alloced_pages(ttm);
 529         return ret;
 530 }
 531
 532 int ttm_tt_swapout(struct ttm_tt *ttm, struct file *persistant_swap_storage)
 533 {
 534         struct address_space *swap_space;
 535         struct file *swap_storage;
 536         struct page *from_page;
 537         struct page *to_page;
 538         void *from_virtual;
 539         void *to_virtual;
 540         int i;
 541         int ret = -ENOMEM;
 542
 543         BUG_ON(ttm->state != tt_unbound && ttm->state != tt_unpopulated);
 544         BUG_ON(ttm->caching_state != tt_cached);
 545
 546         /*
 547          * For user buffers, just unpin the pages, as there should be
 548          * vma references.
 549          */
 550
 551         if (ttm->page_flags & TTM_PAGE_FLAG_USER) {
 552                 ttm_tt_free_user_pages(ttm);
 553                 ttm->page_flags |= TTM_PAGE_FLAG_SWAPPED;
 554                 ttm->swap_storage = NULL;
 555                 return 0;
 556         }
 557
 558         if (!persistant_swap_storage) {
 559                 swap_storage = shmem_file_setup("ttm swap",
 560                                                 ttm->num_pages << PAGE_SHIFT,
 561                                                 0);
 562                 if (unlikely(IS_ERR(swap_storage))) {
 563                         printk(KERN_ERR "Failed allocating swap storage.\n");
 564                         return PTR_ERR(swap_storage);
 565                 }
 566         } else
 567                 swap_storage = persistant_swap_storage;
 568
 569         swap_space = swap_storage->f_path.dentry->d_inode->i_mapping;
 570
 571         for (i = 0; i < ttm->num_pages; ++i) {
 572                 from_page = ttm->pages[i];
 573                 if (unlikely(from_page == NULL))
 574                         continue;
 575                 to_page = read_mapping_page(swap_space, i, NULL);
 576                 if (unlikely(IS_ERR(to_page))) {
 577                         ret = PTR_ERR(to_page);
 578                         goto out_err;
 579                 }
 580                 preempt_disable();
 581                 from_virtual = kmap_atomic(from_page, KM_USER0);
 582                 to_virtual = kmap_atomic(to_page, KM_USER1);
 583                 memcpy(to_virtual, from_virtual, PAGE_SIZE);
 584                 kunmap_atomic(to_virtual, KM_USER1);
 585                 kunmap_atomic(from_virtual, KM_USER0);
 586                 preempt_enable();
 587                 set_page_dirty(to_page);
 588                 mark_page_accessed(to_page);
 589                 page_cache_release(to_page);
 590         }
 591
 592         ttm_tt_free_alloced_pages(ttm);
 593         ttm->swap_storage = swap_storage;
 594         ttm->page_flags |= TTM_PAGE_FLAG_SWAPPED;
 595         if (persistant_swap_storage)
 596                 ttm->page_flags |= TTM_PAGE_FLAG_PERSISTANT_SWAP;
 597
 598         return 0;
 599 out_err:
 600         if (!persistant_swap_storage)
 601                 fput(swap_storage);
 602
 603         return ret;
 604 }