/* SPDX-License-Identifier: GPL-2.0 OR MIT */ /************************************************************************** * * Copyright (c) 2006-2009 VMware, Inc., Palo Alto, CA., USA * All Rights Reserved. * * Permission is hereby granted, free of charge, to any person obtaining a * copy of this software and associated documentation files (the * "Software"), to deal in the Software without restriction, including * without limitation the rights to use, copy, modify, merge, publish, * distribute, sub license, and/or sell copies of the Software, and to * permit persons to whom the Software is furnished to do so, subject to * the following conditions: * * The above copyright notice and this permission notice (including the * next paragraph) shall be included in all copies or substantial portions * of the Software. * * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, * FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL * THE COPYRIGHT HOLDERS, AUTHORS AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM, * DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR * OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE * USE OR OTHER DEALINGS IN THE SOFTWARE. * **************************************************************************/ /* * Authors: Thomas Hellstrom */ #define pr_fmt(fmt) "[TTM] " fmt #include #include #include #include #include #include #include #include #include #include #include static vm_fault_t ttm_bo_vm_fault_idle(struct ttm_buffer_object *bo, struct vm_fault *vmf) { vm_fault_t ret = 0; int err = 0; if (likely(!bo->moving)) goto out_unlock; /* * Quick non-stalling check for idle. */ if (dma_fence_is_signaled(bo->moving)) goto out_clear; /* * If possible, avoid waiting for GPU with mmap_lock * held. We only do this if the fault allows retry and this * is the first attempt. */ if (fault_flag_allow_retry_first(vmf->flags)) { ret = VM_FAULT_RETRY; if (vmf->flags & FAULT_FLAG_RETRY_NOWAIT) goto out_unlock; ttm_bo_get(bo); mmap_read_unlock(vmf->vma->vm_mm); (void) dma_fence_wait(bo->moving, true); dma_resv_unlock(bo->base.resv); ttm_bo_put(bo); goto out_unlock; } /* * Ordinary wait. */ err = dma_fence_wait(bo->moving, true); if (unlikely(err != 0)) { ret = (err != -ERESTARTSYS) ? VM_FAULT_SIGBUS : VM_FAULT_NOPAGE; goto out_unlock; } out_clear: dma_fence_put(bo->moving); bo->moving = NULL; out_unlock: return ret; } static unsigned long ttm_bo_io_mem_pfn(struct ttm_buffer_object *bo, unsigned long page_offset) { struct ttm_device *bdev = bo->bdev; if (bdev->funcs->io_mem_pfn) return bdev->funcs->io_mem_pfn(bo, page_offset); return (bo->resource->bus.offset >> PAGE_SHIFT) + page_offset; } /** * ttm_bo_vm_reserve - Reserve a buffer object in a retryable vm callback * @bo: The buffer object * @vmf: The fault structure handed to the callback * * vm callbacks like fault() and *_mkwrite() allow for the mm_sem to be dropped * during long waits, and after the wait the callback will be restarted. This * is to allow other threads using the same virtual memory space concurrent * access to map(), unmap() completely unrelated buffer objects. TTM buffer * object reservations sometimes wait for GPU and should therefore be * considered long waits. This function reserves the buffer object interruptibly * taking this into account. Starvation is avoided by the vm system not * allowing too many repeated restarts. * This function is intended to be used in customized fault() and _mkwrite() * handlers. * * Return: * 0 on success and the bo was reserved. * VM_FAULT_RETRY if blocking wait. * VM_FAULT_NOPAGE if blocking wait and retrying was not allowed. */ vm_fault_t ttm_bo_vm_reserve(struct ttm_buffer_object *bo, struct vm_fault *vmf) { /* * Work around locking order reversal in fault / nopfn * between mmap_lock and bo_reserve: Perform a trylock operation * for reserve, and if it fails, retry the fault after waiting * for the buffer to become unreserved. */ if (unlikely(!dma_resv_trylock(bo->base.resv))) { /* * If the fault allows retry and this is the first * fault attempt, we try to release the mmap_lock * before waiting */ if (fault_flag_allow_retry_first(vmf->flags)) { if (!(vmf->flags & FAULT_FLAG_RETRY_NOWAIT)) { ttm_bo_get(bo); mmap_read_unlock(vmf->vma->vm_mm); if (!dma_resv_lock_interruptible(bo->base.resv, NULL)) dma_resv_unlock(bo->base.resv); ttm_bo_put(bo); } return VM_FAULT_RETRY; } if (dma_resv_lock_interruptible(bo->base.resv, NULL)) return VM_FAULT_NOPAGE; } /* * Refuse to fault imported pages. This should be handled * (if at all) by redirecting mmap to the exporter. */ if (bo->ttm && (bo->ttm->page_flags & TTM_TT_FLAG_EXTERNAL)) { if (!(bo->ttm->page_flags & TTM_TT_FLAG_EXTERNAL_MAPPABLE)) { dma_resv_unlock(bo->base.resv); return VM_FAULT_SIGBUS; } } return 0; } EXPORT_SYMBOL(ttm_bo_vm_reserve); #ifdef CONFIG_TRANSPARENT_HUGEPAGE /** * ttm_bo_vm_insert_huge - Insert a pfn for PUD or PMD faults * @vmf: Fault data * @bo: The buffer object * @page_offset: Page offset from bo start * @fault_page_size: The size of the fault in pages. * @pgprot: The page protections. * Does additional checking whether it's possible to insert a PUD or PMD * pfn and performs the insertion. * * Return: VM_FAULT_NOPAGE on successful insertion, VM_FAULT_FALLBACK if * a huge fault was not possible, or on insertion error. */ static vm_fault_t ttm_bo_vm_insert_huge(struct vm_fault *vmf, struct ttm_buffer_object *bo, pgoff_t page_offset, pgoff_t fault_page_size, pgprot_t pgprot) { pgoff_t i; vm_fault_t ret; unsigned long pfn; pfn_t pfnt; struct ttm_tt *ttm = bo->ttm; bool write = vmf->flags & FAULT_FLAG_WRITE; /* Fault should not cross bo boundary. */ page_offset &= ~(fault_page_size - 1); if (page_offset + fault_page_size > bo->resource->num_pages) goto out_fallback; if (bo->resource->bus.is_iomem) pfn = ttm_bo_io_mem_pfn(bo, page_offset); else pfn = page_to_pfn(ttm->pages[page_offset]); /* pfn must be fault_page_size aligned. */ if ((pfn & (fault_page_size - 1)) != 0) goto out_fallback; /* Check that memory is contiguous. */ if (!bo->resource->bus.is_iomem) { for (i = 1; i < fault_page_size; ++i) { if (page_to_pfn(ttm->pages[page_offset + i]) != pfn + i) goto out_fallback; } } else if (bo->bdev->funcs->io_mem_pfn) { for (i = 1; i < fault_page_size; ++i) { if (ttm_bo_io_mem_pfn(bo, page_offset + i) != pfn + i) goto out_fallback; } } pfnt = __pfn_to_pfn_t(pfn, PFN_DEV); if (fault_page_size == (HPAGE_PMD_SIZE >> PAGE_SHIFT)) ret = vmf_insert_pfn_pmd_prot(vmf, pfnt, pgprot, write); #ifdef CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD else if (fault_page_size == (HPAGE_PUD_SIZE >> PAGE_SHIFT)) ret = vmf_insert_pfn_pud_prot(vmf, pfnt, pgprot, write); #endif else WARN_ON_ONCE(ret = VM_FAULT_FALLBACK); if (ret != VM_FAULT_NOPAGE) goto out_fallback; return VM_FAULT_NOPAGE; out_fallback: count_vm_event(THP_FAULT_FALLBACK); return VM_FAULT_FALLBACK; } #else static vm_fault_t ttm_bo_vm_insert_huge(struct vm_fault *vmf, struct ttm_buffer_object *bo, pgoff_t page_offset, pgoff_t fault_page_size, pgprot_t pgprot) { return VM_FAULT_FALLBACK; } #endif /** * ttm_bo_vm_fault_reserved - TTM fault helper * @vmf: The struct vm_fault given as argument to the fault callback * @prot: The page protection to be used for this memory area. * @num_prefault: Maximum number of prefault pages. The caller may want to * specify this based on madvice settings and the size of the GPU object * backed by the memory. * @fault_page_size: The size of the fault in pages. * * This function inserts one or more page table entries pointing to the * memory backing the buffer object, and then returns a return code * instructing the caller to retry the page access. * * Return: * VM_FAULT_NOPAGE on success or pending signal * VM_FAULT_SIGBUS on unspecified error * VM_FAULT_OOM on out-of-memory * VM_FAULT_RETRY if retryable wait */ vm_fault_t ttm_bo_vm_fault_reserved(struct vm_fault *vmf, pgprot_t prot, pgoff_t num_prefault, pgoff_t fault_page_size) { struct vm_area_struct *vma = vmf->vma; struct ttm_buffer_object *bo = vma->vm_private_data; struct ttm_device *bdev = bo->bdev; unsigned long page_offset; unsigned long page_last; unsigned long pfn; struct ttm_tt *ttm = NULL; struct page *page; int err; pgoff_t i; vm_fault_t ret = VM_FAULT_NOPAGE; unsigned long address = vmf->address; /* * Wait for buffer data in transit, due to a pipelined * move. */ ret = ttm_bo_vm_fault_idle(bo, vmf); if (unlikely(ret != 0)) return ret; err = ttm_mem_io_reserve(bdev, bo->resource); if (unlikely(err != 0)) return VM_FAULT_SIGBUS; page_offset = ((address - vma->vm_start) >> PAGE_SHIFT) + vma->vm_pgoff - drm_vma_node_start(&bo->base.vma_node); page_last = vma_pages(vma) + vma->vm_pgoff - drm_vma_node_start(&bo->base.vma_node); if (unlikely(page_offset >= bo->resource->num_pages)) return VM_FAULT_SIGBUS; prot = ttm_io_prot(bo, bo->resource, prot); if (!bo->resource->bus.is_iomem) { struct ttm_operation_ctx ctx = { .interruptible = false, .no_wait_gpu = false, .force_alloc = true }; ttm = bo->ttm; if (ttm_tt_populate(bdev, bo->ttm, &ctx)) return VM_FAULT_OOM; } else { /* Iomem should not be marked encrypted */ prot = pgprot_decrypted(prot); } /* We don't prefault on huge faults. Yet. */ if (IS_ENABLED(CONFIG_TRANSPARENT_HUGEPAGE) && fault_page_size != 1) return ttm_bo_vm_insert_huge(vmf, bo, page_offset, fault_page_size, prot); /* * Speculatively prefault a number of pages. Only error on * first page. */ for (i = 0; i < num_prefault; ++i) { if (bo->resource->bus.is_iomem) { pfn = ttm_bo_io_mem_pfn(bo, page_offset); } else { page = ttm->pages[page_offset]; if (unlikely(!page && i == 0)) { return VM_FAULT_OOM; } else if (unlikely(!page)) { break; } pfn = page_to_pfn(page); } /* * Note that the value of @prot at this point may differ from * the value of @vma->vm_page_prot in the caching- and * encryption bits. This is because the exact location of the * data may not be known at mmap() time and may also change * at arbitrary times while the data is mmap'ed. * See vmf_insert_mixed_prot() for a discussion. */ ret = vmf_insert_pfn_prot(vma, address, pfn, prot); /* Never error on prefaulted PTEs */ if (unlikely((ret & VM_FAULT_ERROR))) { if (i == 0) return VM_FAULT_NOPAGE; else break; } address += PAGE_SIZE; if (unlikely(++page_offset >= page_last)) break; } return ret; } EXPORT_SYMBOL(ttm_bo_vm_fault_reserved); static void ttm_bo_release_dummy_page(struct drm_device *dev, void *res) { struct page *dummy_page = (struct page *)res; __free_page(dummy_page); } vm_fault_t ttm_bo_vm_dummy_page(struct vm_fault *vmf, pgprot_t prot) { struct vm_area_struct *vma = vmf->vma; struct ttm_buffer_object *bo = vma->vm_private_data; struct drm_device *ddev = bo->base.dev; vm_fault_t ret = VM_FAULT_NOPAGE; unsigned long address; unsigned long pfn; struct page *page; /* Allocate new dummy page to map all the VA range in this VMA to it*/ page = alloc_page(GFP_KERNEL | __GFP_ZERO); if (!page) return VM_FAULT_OOM; /* Set the page to be freed using drmm release action */ if (drmm_add_action_or_reset(ddev, ttm_bo_release_dummy_page, page)) return VM_FAULT_OOM; pfn = page_to_pfn(page); /* Prefault the entire VMA range right away to avoid further faults */ for (address = vma->vm_start; address < vma->vm_end; address += PAGE_SIZE) ret = vmf_insert_pfn_prot(vma, address, pfn, prot); return ret; } EXPORT_SYMBOL(ttm_bo_vm_dummy_page); vm_fault_t ttm_bo_vm_fault(struct vm_fault *vmf) { struct vm_area_struct *vma = vmf->vma; pgprot_t prot; struct ttm_buffer_object *bo = vma->vm_private_data; struct drm_device *ddev = bo->base.dev; vm_fault_t ret; int idx; ret = ttm_bo_vm_reserve(bo, vmf); if (ret) return ret; prot = vma->vm_page_prot; if (drm_dev_enter(ddev, &idx)) { ret = ttm_bo_vm_fault_reserved(vmf, prot, TTM_BO_VM_NUM_PREFAULT, 1); drm_dev_exit(idx); } else { ret = ttm_bo_vm_dummy_page(vmf, prot); } if (ret == VM_FAULT_RETRY && !(vmf->flags & FAULT_FLAG_RETRY_NOWAIT)) return ret; dma_resv_unlock(bo->base.resv); return ret; } EXPORT_SYMBOL(ttm_bo_vm_fault); void ttm_bo_vm_open(struct vm_area_struct *vma) { struct ttm_buffer_object *bo = vma->vm_private_data; WARN_ON(bo->bdev->dev_mapping != vma->vm_file->f_mapping); ttm_bo_get(bo); } EXPORT_SYMBOL(ttm_bo_vm_open); void ttm_bo_vm_close(struct vm_area_struct *vma) { struct ttm_buffer_object *bo = vma->vm_private_data; ttm_bo_put(bo); vma->vm_private_data = NULL; } EXPORT_SYMBOL(ttm_bo_vm_close); static int ttm_bo_vm_access_kmap(struct ttm_buffer_object *bo, unsigned long offset, uint8_t *buf, int len, int write) { unsigned long page = offset >> PAGE_SHIFT; unsigned long bytes_left = len; int ret; /* Copy a page at a time, that way no extra virtual address * mapping is needed */ offset -= page << PAGE_SHIFT; do { unsigned long bytes = min(bytes_left, PAGE_SIZE - offset); struct ttm_bo_kmap_obj map; void *ptr; bool is_iomem; ret = ttm_bo_kmap(bo, page, 1, &map); if (ret) return ret; ptr = (uint8_t *)ttm_kmap_obj_virtual(&map, &is_iomem) + offset; WARN_ON_ONCE(is_iomem); if (write) memcpy(ptr, buf, bytes); else memcpy(buf, ptr, bytes); ttm_bo_kunmap(&map); page++; buf += bytes; bytes_left -= bytes; offset = 0; } while (bytes_left); return len; } int ttm_bo_vm_access(struct vm_area_struct *vma, unsigned long addr, void *buf, int len, int write) { struct ttm_buffer_object *bo = vma->vm_private_data; unsigned long offset = (addr) - vma->vm_start + ((vma->vm_pgoff - drm_vma_node_start(&bo->base.vma_node)) << PAGE_SHIFT); int ret; if (len < 1 || (offset + len) >> PAGE_SHIFT > bo->resource->num_pages) return -EIO; ret = ttm_bo_reserve(bo, true, false, NULL); if (ret) return ret; switch (bo->resource->mem_type) { case TTM_PL_SYSTEM: fallthrough; case TTM_PL_TT: ret = ttm_bo_vm_access_kmap(bo, offset, buf, len, write); break; default: if (bo->bdev->funcs->access_memory) ret = bo->bdev->funcs->access_memory( bo, offset, buf, len, write); else ret = -EIO; } ttm_bo_unreserve(bo); return ret; } EXPORT_SYMBOL(ttm_bo_vm_access); static const struct vm_operations_struct ttm_bo_vm_ops = { .fault = ttm_bo_vm_fault, .open = ttm_bo_vm_open, .close = ttm_bo_vm_close, .access = ttm_bo_vm_access, }; int ttm_bo_mmap_obj(struct vm_area_struct *vma, struct ttm_buffer_object *bo) { /* Enforce no COW since would have really strange behavior with it. */ if (is_cow_mapping(vma->vm_flags)) return -EINVAL; ttm_bo_get(bo); /* * Drivers may want to override the vm_ops field. Otherwise we * use TTM's default callbacks. */ if (!vma->vm_ops) vma->vm_ops = &ttm_bo_vm_ops; /* * Note: We're transferring the bo reference to * vma->vm_private_data here. */ vma->vm_private_data = bo; vma->vm_flags |= VM_PFNMAP; vma->vm_flags |= VM_IO | VM_DONTEXPAND | VM_DONTDUMP; return 0; } EXPORT_SYMBOL(ttm_bo_mmap_obj);