drivers/gpu/drm/ttm/ttm_bo_vm.c

   1 /* SPDX-License-Identifier: GPL-2.0 OR MIT */
   2 /**************************************************************************
   3  *
   4  * Copyright (c) 2006-2009 VMware, Inc., Palo Alto, CA., USA
   5  * All Rights Reserved.
   6  *
   7  * Permission is hereby granted, free of charge, to any person obtaining a
   8  * copy of this software and associated documentation files (the
   9  * "Software"), to deal in the Software without restriction, including
  10  * without limitation the rights to use, copy, modify, merge, publish,
  11  * distribute, sub license, and/or sell copies of the Software, and to
  12  * permit persons to whom the Software is furnished to do so, subject to
  13  * the following conditions:
  14  *
  15  * The above copyright notice and this permission notice (including the
  16  * next paragraph) shall be included in all copies or substantial portions
  17  * of the Software.
  18  *
  19  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  20  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  21  * FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL
  22  * THE COPYRIGHT HOLDERS, AUTHORS AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM,
  23  * DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
  24  * OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
  25  * USE OR OTHER DEALINGS IN THE SOFTWARE.
  26  *
  27  **************************************************************************/
  28 /*
  29  * Authors: Thomas Hellstrom <thellstrom-at-vmware-dot-com>
  30  */
  31
  32 #define pr_fmt(fmt) "[TTM] " fmt
  33
  34 #include <drm/ttm/ttm_bo.h>
  35 #include <drm/ttm/ttm_placement.h>
  36 #include <drm/ttm/ttm_tt.h>
  37
  38 #include <drm/drm_drv.h>
  39 #include <drm/drm_managed.h>
  40
  41 static vm_fault_t ttm_bo_vm_fault_idle(struct ttm_buffer_object *bo,
  42                                 struct vm_fault *vmf)
  43 {
  44         long err = 0;
  45
  46         /*
  47          * Quick non-stalling check for idle.
  48          */
  49         if (dma_resv_test_signaled(bo->base.resv, DMA_RESV_USAGE_KERNEL))
  50                 return 0;
  51
  52         /*
  53          * If possible, avoid waiting for GPU with mmap_lock
  54          * held.  We only do this if the fault allows retry and this
  55          * is the first attempt.
  56          */
  57         if (fault_flag_allow_retry_first(vmf->flags)) {
  58                 if (vmf->flags & FAULT_FLAG_RETRY_NOWAIT)
  59                         return VM_FAULT_RETRY;
  60
  61                 ttm_bo_get(bo);
  62                 mmap_read_unlock(vmf->vma->vm_mm);
  63                 (void)dma_resv_wait_timeout(bo->base.resv,
  64                                             DMA_RESV_USAGE_KERNEL, true,
  65                                             MAX_SCHEDULE_TIMEOUT);
  66                 dma_resv_unlock(bo->base.resv);
  67                 ttm_bo_put(bo);
  68                 return VM_FAULT_RETRY;
  69         }
  70
  71         /*
  72          * Ordinary wait.
  73          */
  74         err = dma_resv_wait_timeout(bo->base.resv, DMA_RESV_USAGE_KERNEL, true,
  75                                     MAX_SCHEDULE_TIMEOUT);
  76         if (unlikely(err < 0)) {
  77                 return (err != -ERESTARTSYS) ? VM_FAULT_SIGBUS :
  78                         VM_FAULT_NOPAGE;
  79         }
  80
  81         return 0;
  82 }
  83
  84 static unsigned long ttm_bo_io_mem_pfn(struct ttm_buffer_object *bo,
  85                                        unsigned long page_offset)
  86 {
  87         struct ttm_device *bdev = bo->bdev;
  88
  89         if (bdev->funcs->io_mem_pfn)
  90                 return bdev->funcs->io_mem_pfn(bo, page_offset);
  91
  92         return (bo->resource->bus.offset >> PAGE_SHIFT) + page_offset;
  93 }
  94
  95 /**
  96  * ttm_bo_vm_reserve - Reserve a buffer object in a retryable vm callback
  97  * @bo: The buffer object
  98  * @vmf: The fault structure handed to the callback
  99  *
 100  * vm callbacks like fault() and *_mkwrite() allow for the mmap_lock to be dropped
 101  * during long waits, and after the wait the callback will be restarted. This
 102  * is to allow other threads using the same virtual memory space concurrent
 103  * access to map(), unmap() completely unrelated buffer objects. TTM buffer
 104  * object reservations sometimes wait for GPU and should therefore be
 105  * considered long waits. This function reserves the buffer object interruptibly
 106  * taking this into account. Starvation is avoided by the vm system not
 107  * allowing too many repeated restarts.
 108  * This function is intended to be used in customized fault() and _mkwrite()
 109  * handlers.
 110  *
 111  * Return:
 112  *    0 on success and the bo was reserved.
 113  *    VM_FAULT_RETRY if blocking wait.
 114  *    VM_FAULT_NOPAGE if blocking wait and retrying was not allowed.
 115  */
 116 vm_fault_t ttm_bo_vm_reserve(struct ttm_buffer_object *bo,
 117                              struct vm_fault *vmf)
 118 {
 119         /*
 120          * Work around locking order reversal in fault / nopfn
 121          * between mmap_lock and bo_reserve: Perform a trylock operation
 122          * for reserve, and if it fails, retry the fault after waiting
 123          * for the buffer to become unreserved.
 124          */
 125         if (unlikely(!dma_resv_trylock(bo->base.resv))) {
 126                 /*
 127                  * If the fault allows retry and this is the first
 128                  * fault attempt, we try to release the mmap_lock
 129                  * before waiting
 130                  */
 131                 if (fault_flag_allow_retry_first(vmf->flags)) {
 132                         if (!(vmf->flags & FAULT_FLAG_RETRY_NOWAIT)) {
 133                                 ttm_bo_get(bo);
 134                                 mmap_read_unlock(vmf->vma->vm_mm);
 135                                 if (!dma_resv_lock_interruptible(bo->base.resv,
 136                                                                  NULL))
 137                                         dma_resv_unlock(bo->base.resv);
 138                                 ttm_bo_put(bo);
 139                         }
 140
 141                         return VM_FAULT_RETRY;
 142                 }
 143
 144                 if (dma_resv_lock_interruptible(bo->base.resv, NULL))
 145                         return VM_FAULT_NOPAGE;
 146         }
 147
 148         /*
 149          * Refuse to fault imported pages. This should be handled
 150          * (if at all) by redirecting mmap to the exporter.
 151          */
 152         if (bo->ttm && (bo->ttm->page_flags & TTM_TT_FLAG_EXTERNAL)) {
 153                 if (!(bo->ttm->page_flags & TTM_TT_FLAG_EXTERNAL_MAPPABLE)) {
 154                         dma_resv_unlock(bo->base.resv);
 155                         return VM_FAULT_SIGBUS;
 156                 }
 157         }
 158
 159         return 0;
 160 }
 161 EXPORT_SYMBOL(ttm_bo_vm_reserve);
 162
 163 /**
 164  * ttm_bo_vm_fault_reserved - TTM fault helper
 165  * @vmf: The struct vm_fault given as argument to the fault callback
 166  * @prot: The page protection to be used for this memory area.
 167  * @num_prefault: Maximum number of prefault pages. The caller may want to
 168  * specify this based on madvice settings and the size of the GPU object
 169  * backed by the memory.
 170  *
 171  * This function inserts one or more page table entries pointing to the
 172  * memory backing the buffer object, and then returns a return code
 173  * instructing the caller to retry the page access.
 174  *
 175  * Return:
 176  *   VM_FAULT_NOPAGE on success or pending signal
 177  *   VM_FAULT_SIGBUS on unspecified error
 178  *   VM_FAULT_OOM on out-of-memory
 179  *   VM_FAULT_RETRY if retryable wait
 180  */
 181 vm_fault_t ttm_bo_vm_fault_reserved(struct vm_fault *vmf,
 182                                     pgprot_t prot,
 183                                     pgoff_t num_prefault)
 184 {
 185         struct vm_area_struct *vma = vmf->vma;
 186         struct ttm_buffer_object *bo = vma->vm_private_data;
 187         struct ttm_device *bdev = bo->bdev;
 188         unsigned long page_offset;
 189         unsigned long page_last;
 190         unsigned long pfn;
 191         struct ttm_tt *ttm = NULL;
 192         struct page *page;
 193         int err;
 194         pgoff_t i;
 195         vm_fault_t ret = VM_FAULT_NOPAGE;
 196         unsigned long address = vmf->address;
 197
 198         /*
 199          * Wait for buffer data in transit, due to a pipelined
 200          * move.
 201          */
 202         ret = ttm_bo_vm_fault_idle(bo, vmf);
 203         if (unlikely(ret != 0))
 204                 return ret;
 205
 206         err = ttm_mem_io_reserve(bdev, bo->resource);
 207         if (unlikely(err != 0))
 208                 return VM_FAULT_SIGBUS;
 209
 210         page_offset = ((address - vma->vm_start) >> PAGE_SHIFT) +
 211                 vma->vm_pgoff - drm_vma_node_start(&bo->base.vma_node);
 212         page_last = vma_pages(vma) + vma->vm_pgoff -
 213                 drm_vma_node_start(&bo->base.vma_node);
 214
 215         if (unlikely(page_offset >= PFN_UP(bo->base.size)))
 216                 return VM_FAULT_SIGBUS;
 217
 218         prot = ttm_io_prot(bo, bo->resource, prot);
 219         if (!bo->resource->bus.is_iomem) {
 220                 struct ttm_operation_ctx ctx = {
 221                         .interruptible = false,
 222                         .no_wait_gpu = false,
 223                         .force_alloc = true
 224                 };
 225
 226                 ttm = bo->ttm;
 227                 if (ttm_tt_populate(bdev, bo->ttm, &ctx))
 228                         return VM_FAULT_OOM;
 229         } else {
 230                 /* Iomem should not be marked encrypted */
 231                 prot = pgprot_decrypted(prot);
 232         }
 233
 234         /*
 235          * Speculatively prefault a number of pages. Only error on
 236          * first page.
 237          */
 238         for (i = 0; i < num_prefault; ++i) {
 239                 if (bo->resource->bus.is_iomem) {
 240                         pfn = ttm_bo_io_mem_pfn(bo, page_offset);
 241                 } else {
 242                         page = ttm->pages[page_offset];
 243                         if (unlikely(!page && i == 0)) {
 244                                 return VM_FAULT_OOM;
 245                         } else if (unlikely(!page)) {
 246                                 break;
 247                         }
 248                         pfn = page_to_pfn(page);
 249                 }
 250
 251                 /*
 252                  * Note that the value of @prot at this point may differ from
 253                  * the value of @vma->vm_page_prot in the caching- and
 254                  * encryption bits. This is because the exact location of the
 255                  * data may not be known at mmap() time and may also change
 256                  * at arbitrary times while the data is mmap'ed.
 257                  * See vmf_insert_pfn_prot() for a discussion.
 258                  */
 259                 ret = vmf_insert_pfn_prot(vma, address, pfn, prot);
 260
 261                 /* Never error on prefaulted PTEs */
 262                 if (unlikely((ret & VM_FAULT_ERROR))) {
 263                         if (i == 0)
 264                                 return VM_FAULT_NOPAGE;
 265                         else
 266                                 break;
 267                 }
 268
 269                 address += PAGE_SIZE;
 270                 if (unlikely(++page_offset >= page_last))
 271                         break;
 272         }
 273         return ret;
 274 }
 275 EXPORT_SYMBOL(ttm_bo_vm_fault_reserved);
 276
 277 static void ttm_bo_release_dummy_page(struct drm_device *dev, void *res)
 278 {
 279         struct page *dummy_page = (struct page *)res;
 280
 281         __free_page(dummy_page);
 282 }
 283
 284 vm_fault_t ttm_bo_vm_dummy_page(struct vm_fault *vmf, pgprot_t prot)
 285 {
 286         struct vm_area_struct *vma = vmf->vma;
 287         struct ttm_buffer_object *bo = vma->vm_private_data;
 288         struct drm_device *ddev = bo->base.dev;
 289         vm_fault_t ret = VM_FAULT_NOPAGE;
 290         unsigned long address;
 291         unsigned long pfn;
 292         struct page *page;
 293
 294         /* Allocate new dummy page to map all the VA range in this VMA to it*/
 295         page = alloc_page(GFP_KERNEL | __GFP_ZERO);
 296         if (!page)
 297                 return VM_FAULT_OOM;
 298
 299         /* Set the page to be freed using drmm release action */
 300         if (drmm_add_action_or_reset(ddev, ttm_bo_release_dummy_page, page))
 301                 return VM_FAULT_OOM;
 302
 303         pfn = page_to_pfn(page);
 304
 305         /* Prefault the entire VMA range right away to avoid further faults */
 306         for (address = vma->vm_start; address < vma->vm_end;
 307              address += PAGE_SIZE)
 308                 ret = vmf_insert_pfn_prot(vma, address, pfn, prot);
 309
 310         return ret;
 311 }
 312 EXPORT_SYMBOL(ttm_bo_vm_dummy_page);
 313
 314 vm_fault_t ttm_bo_vm_fault(struct vm_fault *vmf)
 315 {
 316         struct vm_area_struct *vma = vmf->vma;
 317         pgprot_t prot;
 318         struct ttm_buffer_object *bo = vma->vm_private_data;
 319         struct drm_device *ddev = bo->base.dev;
 320         vm_fault_t ret;
 321         int idx;
 322
 323         ret = ttm_bo_vm_reserve(bo, vmf);
 324         if (ret)
 325                 return ret;
 326
 327         prot = vma->vm_page_prot;
 328         if (drm_dev_enter(ddev, &idx)) {
 329                 ret = ttm_bo_vm_fault_reserved(vmf, prot, TTM_BO_VM_NUM_PREFAULT);
 330                 drm_dev_exit(idx);
 331         } else {
 332                 ret = ttm_bo_vm_dummy_page(vmf, prot);
 333         }
 334         if (ret == VM_FAULT_RETRY && !(vmf->flags & FAULT_FLAG_RETRY_NOWAIT))
 335                 return ret;
 336
 337         dma_resv_unlock(bo->base.resv);
 338
 339         return ret;
 340 }
 341 EXPORT_SYMBOL(ttm_bo_vm_fault);
 342
 343 void ttm_bo_vm_open(struct vm_area_struct *vma)
 344 {
 345         struct ttm_buffer_object *bo = vma->vm_private_data;
 346
 347         WARN_ON(bo->bdev->dev_mapping != vma->vm_file->f_mapping);
 348
 349         ttm_bo_get(bo);
 350 }
 351 EXPORT_SYMBOL(ttm_bo_vm_open);
 352
 353 void ttm_bo_vm_close(struct vm_area_struct *vma)
 354 {
 355         struct ttm_buffer_object *bo = vma->vm_private_data;
 356
 357         ttm_bo_put(bo);
 358         vma->vm_private_data = NULL;
 359 }
 360 EXPORT_SYMBOL(ttm_bo_vm_close);
 361
 362 static int ttm_bo_vm_access_kmap(struct ttm_buffer_object *bo,
 363                                  unsigned long offset,
 364                                  uint8_t *buf, int len, int write)
 365 {
 366         unsigned long page = offset >> PAGE_SHIFT;
 367         unsigned long bytes_left = len;
 368         int ret;
 369
 370         /* Copy a page at a time, that way no extra virtual address
 371          * mapping is needed
 372          */
 373         offset -= page << PAGE_SHIFT;
 374         do {
 375                 unsigned long bytes = min(bytes_left, PAGE_SIZE - offset);
 376                 struct ttm_bo_kmap_obj map;
 377                 void *ptr;
 378                 bool is_iomem;
 379
 380                 ret = ttm_bo_kmap(bo, page, 1, &map);
 381                 if (ret)
 382                         return ret;
 383
 384                 ptr = (uint8_t *)ttm_kmap_obj_virtual(&map, &is_iomem) + offset;
 385                 WARN_ON_ONCE(is_iomem);
 386                 if (write)
 387                         memcpy(ptr, buf, bytes);
 388                 else
 389                         memcpy(buf, ptr, bytes);
 390                 ttm_bo_kunmap(&map);
 391
 392                 page++;
 393                 buf += bytes;
 394                 bytes_left -= bytes;
 395                 offset = 0;
 396         } while (bytes_left);
 397
 398         return len;
 399 }
 400
 401 int ttm_bo_vm_access(struct vm_area_struct *vma, unsigned long addr,
 402                      void *buf, int len, int write)
 403 {
 404         struct ttm_buffer_object *bo = vma->vm_private_data;
 405         unsigned long offset = (addr) - vma->vm_start +
 406                 ((vma->vm_pgoff - drm_vma_node_start(&bo->base.vma_node))
 407                  << PAGE_SHIFT);
 408         int ret;
 409
 410         if (len < 1 || (offset + len) > bo->base.size)
 411                 return -EIO;
 412
 413         ret = ttm_bo_reserve(bo, true, false, NULL);
 414         if (ret)
 415                 return ret;
 416
 417         switch (bo->resource->mem_type) {
 418         case TTM_PL_SYSTEM:
 419                 fallthrough;
 420         case TTM_PL_TT:
 421                 ret = ttm_bo_vm_access_kmap(bo, offset, buf, len, write);
 422                 break;
 423         default:
 424                 if (bo->bdev->funcs->access_memory)
 425                         ret = bo->bdev->funcs->access_memory(
 426                                 bo, offset, buf, len, write);
 427                 else
 428                         ret = -EIO;
 429         }
 430
 431         ttm_bo_unreserve(bo);
 432
 433         return ret;
 434 }
 435 EXPORT_SYMBOL(ttm_bo_vm_access);
 436
 437 static const struct vm_operations_struct ttm_bo_vm_ops = {
 438         .fault = ttm_bo_vm_fault,
 439         .open = ttm_bo_vm_open,
 440         .close = ttm_bo_vm_close,
 441         .access = ttm_bo_vm_access,
 442 };
 443
 444 /**
 445  * ttm_bo_mmap_obj - mmap memory backed by a ttm buffer object.
 446  *
 447  * @vma:       vma as input from the fbdev mmap method.
 448  * @bo:        The bo backing the address space.
 449  *
 450  * Maps a buffer object.
 451  */
 452 int ttm_bo_mmap_obj(struct vm_area_struct *vma, struct ttm_buffer_object *bo)
 453 {
 454         /* Enforce no COW since would have really strange behavior with it. */
 455         if (is_cow_mapping(vma->vm_flags))
 456                 return -EINVAL;
 457
 458         ttm_bo_get(bo);
 459
 460         /*
 461          * Drivers may want to override the vm_ops field. Otherwise we
 462          * use TTM's default callbacks.
 463          */
 464         if (!vma->vm_ops)
 465                 vma->vm_ops = &ttm_bo_vm_ops;
 466
 467         /*
 468          * Note: We're transferring the bo reference to
 469          * vma->vm_private_data here.
 470          */
 471
 472         vma->vm_private_data = bo;
 473
 474         vm_flags_set(vma, VM_PFNMAP | VM_IO | VM_DONTEXPAND | VM_DONTDUMP);
 475         return 0;
 476 }
 477 EXPORT_SYMBOL(ttm_bo_mmap_obj);