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