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1/* SPDX-License-Identifier: GPL-2.0 OR MIT */2/**************************************************************************3 *4 * Copyright (c) 2006-2009 VMware, Inc., Palo Alto, CA., USA5 * All Rights Reserved.6 *7 * Permission is hereby granted, free of charge, to any person obtaining a8 * copy of this software and associated documentation files (the9 * "Software"), to deal in the Software without restriction, including10 * without limitation the rights to use, copy, modify, merge, publish,11 * distribute, sub license, and/or sell copies of the Software, and to12 * permit persons to whom the Software is furnished to do so, subject to13 * the following conditions:14 *15 * The above copyright notice and this permission notice (including the16 * next paragraph) shall be included in all copies or substantial portions17 * of the Software.18 *19 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR20 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,21 * FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL22 * 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 OR24 * OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE25 * 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] " fmt33 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 41static 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_lock54 * held. We only do this if the fault allows retry and this55 * 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 84static 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 callback97 * @bo: The buffer object98 * @vmf: The fault structure handed to the callback99 *100 * vm callbacks like fault() and *_mkwrite() allow for the mmap_lock to be dropped101 * during long waits, and after the wait the callback will be restarted. This102 * is to allow other threads using the same virtual memory space concurrent103 * access to map(), unmap() completely unrelated buffer objects. TTM buffer104 * object reservations sometimes wait for GPU and should therefore be105 * considered long waits. This function reserves the buffer object interruptibly106 * taking this into account. Starvation is avoided by the vm system not107 * 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 */116vm_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 / nopfn121 * between mmap_lock and bo_reserve: Perform a trylock operation122 * for reserve, and if it fails, retry the fault after waiting123 * 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 first128 * fault attempt, we try to release the mmap_lock129 * before waiting130 */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 handled150 * (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}161EXPORT_SYMBOL(ttm_bo_vm_reserve);162 163/**164 * ttm_bo_vm_fault_reserved - TTM fault helper165 * @vmf: The struct vm_fault given as argument to the fault callback166 * @prot: The page protection to be used for this memory area.167 * @num_prefault: Maximum number of prefault pages. The caller may want to168 * specify this based on madvice settings and the size of the GPU object169 * backed by the memory.170 *171 * This function inserts one or more page table entries pointing to the172 * memory backing the buffer object, and then returns a return code173 * instructing the caller to retry the page access.174 *175 * Return:176 * VM_FAULT_NOPAGE on success or pending signal177 * VM_FAULT_SIGBUS on unspecified error178 * VM_FAULT_OOM on out-of-memory179 * VM_FAULT_RETRY if retryable wait180 */181vm_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 pipelined200 * 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 = true224 };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 on243 * 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 from260 * the value of @vma->vm_page_prot in the caching- and261 * encryption bits. This is because the exact location of the262 * data may not be known at mmap() time and may also change263 * 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 else273 break;274 }275 276 address += PAGE_SIZE;277 if (unlikely(++page_offset >= page_last))278 break;279 }280 return ret;281}282EXPORT_SYMBOL(ttm_bo_vm_fault_reserved);283 284static 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 291vm_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}319EXPORT_SYMBOL(ttm_bo_vm_dummy_page);320 321vm_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}348EXPORT_SYMBOL(ttm_bo_vm_fault);349 350void 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}358EXPORT_SYMBOL(ttm_bo_vm_open);359 360void 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}367EXPORT_SYMBOL(ttm_bo_vm_close);368 369static 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 address378 * mapping is needed379 */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 else396 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 408int 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 else435 ret = -EIO;436 }437 438 ttm_bo_unreserve(bo);439 440 return ret;441}442EXPORT_SYMBOL(ttm_bo_vm_access);443 444static 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 */459int 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 we469 * 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 to476 * 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}484EXPORT_SYMBOL(ttm_bo_mmap_obj);485