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 = true,
 222                         .no_wait_gpu = false,
 223                         .force_alloc = true
 224                 };
 225
 226                 ttm = bo->ttm;
 227                 err = ttm_tt_populate(bdev, bo->ttm, &ctx);
 228                 if (err) {
 229                         if (err == -EINTR || err == -ERESTARTSYS ||
 230                             err == -EAGAIN)
 231                                 return VM_FAULT_NOPAGE;
 232
 233                         pr_debug("TTM fault hit %pe.\n", ERR_PTR(err));
 234                         return VM_FAULT_SIGBUS;
 235                 }
 236         } else {
 237                 /* Iomem should not be marked encrypted */
 238                 prot = pgprot_decrypted(prot);
 239         }
 240
 241         /*
 242          * Speculatively prefault a number of pages. Only error on
 243          * first page.
 244          */
 245         for (i = 0; i < num_prefault; ++i) {
 246                 if (bo->resource->bus.is_iomem) {
 247                         pfn = ttm_bo_io_mem_pfn(bo, page_offset);
 248                 } else {
 249                         page = ttm->pages[page_offset];
 250                         if (unlikely(!page && i == 0)) {
 251                                 return VM_FAULT_OOM;
 252                         } else if (unlikely(!page)) {
 253                                 break;
 254                         }
 255                         pfn = page_to_pfn(page);
 256                 }
 257
 258                 /*
 259                  * Note that the value of @prot at this point may differ from
 260                  * the value of @vma->vm_page_prot in the caching- and
 261                  * encryption bits. This is because the exact location of the
 262                  * data may not be known at mmap() time and may also change
 263                  * at arbitrary times while the data is mmap'ed.
 264                  * See vmf_insert_pfn_prot() for a discussion.
 265                  */
 266                 ret = vmf_insert_pfn_prot(vma, address, pfn, prot);
 267
 268                 /* Never error on prefaulted PTEs */
 269                 if (unlikely((ret & VM_FAULT_ERROR))) {
 270                         if (i == 0)
 271                                 return VM_FAULT_NOPAGE;
 272                         else
 273                                 break;
 274                 }
 275
 276                 address += PAGE_SIZE;
 277                 if (unlikely(++page_offset >= page_last))
 278                         break;
 279         }
 280         return ret;
 281 }
 282 EXPORT_SYMBOL(ttm_bo_vm_fault_reserved);
 283
 284 static void ttm_bo_release_dummy_page(struct drm_device *dev, void *res)
 285 {
 286         struct page *dummy_page = (struct page *)res;
 287
 288         __free_page(dummy_page);
 289 }
 290
 291 vm_fault_t ttm_bo_vm_dummy_page(struct vm_fault *vmf, pgprot_t prot)
 292 {
 293         struct vm_area_struct *vma = vmf->vma;
 294         struct ttm_buffer_object *bo = vma->vm_private_data;
 295         struct drm_device *ddev = bo->base.dev;
 296         vm_fault_t ret = VM_FAULT_NOPAGE;
 297         unsigned long address;
 298         unsigned long pfn;
 299         struct page *page;
 300
 301         /* Allocate new dummy page to map all the VA range in this VMA to it*/
 302         page = alloc_page(GFP_KERNEL | __GFP_ZERO);
 303         if (!page)
 304                 return VM_FAULT_OOM;
 305
 306         /* Set the page to be freed using drmm release action */
 307         if (drmm_add_action_or_reset(ddev, ttm_bo_release_dummy_page, page))
 308                 return VM_FAULT_OOM;
 309
 310         pfn = page_to_pfn(page);
 311
 312         /* Prefault the entire VMA range right away to avoid further faults */
 313         for (address = vma->vm_start; address < vma->vm_end;
 314              address += PAGE_SIZE)
 315                 ret = vmf_insert_pfn_prot(vma, address, pfn, prot);
 316
 317         return ret;
 318 }
 319 EXPORT_SYMBOL(ttm_bo_vm_dummy_page);
 320
 321 vm_fault_t ttm_bo_vm_fault(struct vm_fault *vmf)
 322 {
 323         struct vm_area_struct *vma = vmf->vma;
 324         pgprot_t prot;
 325         struct ttm_buffer_object *bo = vma->vm_private_data;
 326         struct drm_device *ddev = bo->base.dev;
 327         vm_fault_t ret;
 328         int idx;
 329
 330         ret = ttm_bo_vm_reserve(bo, vmf);
 331         if (ret)
 332                 return ret;
 333
 334         prot = vma->vm_page_prot;
 335         if (drm_dev_enter(ddev, &idx)) {
 336                 ret = ttm_bo_vm_fault_reserved(vmf, prot, TTM_BO_VM_NUM_PREFAULT);
 337                 drm_dev_exit(idx);
 338         } else {
 339                 ret = ttm_bo_vm_dummy_page(vmf, prot);
 340         }
 341         if (ret == VM_FAULT_RETRY && !(vmf->flags & FAULT_FLAG_RETRY_NOWAIT))
 342                 return ret;
 343
 344         dma_resv_unlock(bo->base.resv);
 345
 346         return ret;
 347 }
 348 EXPORT_SYMBOL(ttm_bo_vm_fault);
 349
 350 void ttm_bo_vm_open(struct vm_area_struct *vma)
 351 {
 352         struct ttm_buffer_object *bo = vma->vm_private_data;
 353
 354         WARN_ON(bo->bdev->dev_mapping != vma->vm_file->f_mapping);
 355
 356         ttm_bo_get(bo);
 357 }
 358 EXPORT_SYMBOL(ttm_bo_vm_open);
 359
 360 void ttm_bo_vm_close(struct vm_area_struct *vma)
 361 {
 362         struct ttm_buffer_object *bo = vma->vm_private_data;
 363
 364         ttm_bo_put(bo);
 365         vma->vm_private_data = NULL;
 366 }
 367 EXPORT_SYMBOL(ttm_bo_vm_close);
 368
 369 static int ttm_bo_vm_access_kmap(struct ttm_buffer_object *bo,
 370                                  unsigned long offset,
 371                                  uint8_t *buf, int len, int write)
 372 {
 373         unsigned long page = offset >> PAGE_SHIFT;
 374         unsigned long bytes_left = len;
 375         int ret;
 376
 377         /* Copy a page at a time, that way no extra virtual address
 378          * mapping is needed
 379          */
 380         offset -= page << PAGE_SHIFT;
 381         do {
 382                 unsigned long bytes = min(bytes_left, PAGE_SIZE - offset);
 383                 struct ttm_bo_kmap_obj map;
 384                 void *ptr;
 385                 bool is_iomem;
 386
 387                 ret = ttm_bo_kmap(bo, page, 1, &map);
 388                 if (ret)
 389                         return ret;
 390
 391                 ptr = (uint8_t *)ttm_kmap_obj_virtual(&map, &is_iomem) + offset;
 392                 WARN_ON_ONCE(is_iomem);
 393                 if (write)
 394                         memcpy(ptr, buf, bytes);
 395                 else
 396                         memcpy(buf, ptr, bytes);
 397                 ttm_bo_kunmap(&map);
 398
 399                 page++;
 400                 buf += bytes;
 401                 bytes_left -= bytes;
 402                 offset = 0;
 403         } while (bytes_left);
 404
 405         return len;
 406 }
 407
 408 int ttm_bo_vm_access(struct vm_area_struct *vma, unsigned long addr,
 409                      void *buf, int len, int write)
 410 {
 411         struct ttm_buffer_object *bo = vma->vm_private_data;
 412         unsigned long offset = (addr) - vma->vm_start +
 413                 ((vma->vm_pgoff - drm_vma_node_start(&bo->base.vma_node))
 414                  << PAGE_SHIFT);
 415         int ret;
 416
 417         if (len < 1 || (offset + len) > bo->base.size)
 418                 return -EIO;
 419
 420         ret = ttm_bo_reserve(bo, true, false, NULL);
 421         if (ret)
 422                 return ret;
 423
 424         switch (bo->resource->mem_type) {
 425         case TTM_PL_SYSTEM:
 426                 fallthrough;
 427         case TTM_PL_TT:
 428                 ret = ttm_bo_vm_access_kmap(bo, offset, buf, len, write);
 429                 break;
 430         default:
 431                 if (bo->bdev->funcs->access_memory)
 432                         ret = bo->bdev->funcs->access_memory(
 433                                 bo, offset, buf, len, write);
 434                 else
 435                         ret = -EIO;
 436         }
 437
 438         ttm_bo_unreserve(bo);
 439
 440         return ret;
 441 }
 442 EXPORT_SYMBOL(ttm_bo_vm_access);
 443
 444 static const struct vm_operations_struct ttm_bo_vm_ops = {
 445         .fault = ttm_bo_vm_fault,
 446         .open = ttm_bo_vm_open,
 447         .close = ttm_bo_vm_close,
 448         .access = ttm_bo_vm_access,
 449 };
 450
 451 /**
 452  * ttm_bo_mmap_obj - mmap memory backed by a ttm buffer object.
 453  *
 454  * @vma:       vma as input from the fbdev mmap method.
 455  * @bo:        The bo backing the address space.
 456  *
 457  * Maps a buffer object.
 458  */
 459 int ttm_bo_mmap_obj(struct vm_area_struct *vma, struct ttm_buffer_object *bo)
 460 {
 461         /* Enforce no COW since would have really strange behavior with it. */
 462         if (is_cow_mapping(vma->vm_flags))
 463                 return -EINVAL;
 464
 465         ttm_bo_get(bo);
 466
 467         /*
 468          * Drivers may want to override the vm_ops field. Otherwise we
 469          * use TTM's default callbacks.
 470          */
 471         if (!vma->vm_ops)
 472                 vma->vm_ops = &ttm_bo_vm_ops;
 473
 474         /*
 475          * Note: We're transferring the bo reference to
 476          * vma->vm_private_data here.
 477          */
 478
 479         vma->vm_private_data = bo;
 480
 481         vm_flags_set(vma, VM_PFNMAP | VM_IO | VM_DONTEXPAND | VM_DONTDUMP);
 482         return 0;
 483 }
 484 EXPORT_SYMBOL(ttm_bo_mmap_obj);