// SPDX-License-Identifier: GPL-2.0 /* * Copyright 2018 Noralf Trønnes */ #include #include #include #include #include #include #include #include #ifdef CONFIG_X86 #include #endif #include #include #include #include #include #include MODULE_IMPORT_NS(DMA_BUF); /** * DOC: overview * * This library provides helpers for GEM objects backed by shmem buffers * allocated using anonymous pageable memory. * * Functions that operate on the GEM object receive struct &drm_gem_shmem_object. * For GEM callback helpers in struct &drm_gem_object functions, see likewise * named functions with an _object_ infix (e.g., drm_gem_shmem_object_vmap() wraps * drm_gem_shmem_vmap()). These helpers perform the necessary type conversion. */ static const struct drm_gem_object_funcs drm_gem_shmem_funcs = { .free = drm_gem_shmem_object_free, .print_info = drm_gem_shmem_object_print_info, .pin = drm_gem_shmem_object_pin, .unpin = drm_gem_shmem_object_unpin, .get_sg_table = drm_gem_shmem_object_get_sg_table, .vmap = drm_gem_shmem_object_vmap, .vunmap = drm_gem_shmem_object_vunmap, .mmap = drm_gem_shmem_object_mmap, .vm_ops = &drm_gem_shmem_vm_ops, }; static struct drm_gem_shmem_object * __drm_gem_shmem_create(struct drm_device *dev, size_t size, bool private) { struct drm_gem_shmem_object *shmem; struct drm_gem_object *obj; int ret = 0; size = PAGE_ALIGN(size); if (dev->driver->gem_create_object) { obj = dev->driver->gem_create_object(dev, size); if (IS_ERR(obj)) return ERR_CAST(obj); shmem = to_drm_gem_shmem_obj(obj); } else { shmem = kzalloc(sizeof(*shmem), GFP_KERNEL); if (!shmem) return ERR_PTR(-ENOMEM); obj = &shmem->base; } if (!obj->funcs) obj->funcs = &drm_gem_shmem_funcs; if (private) { drm_gem_private_object_init(dev, obj, size); shmem->map_wc = false; /* dma-buf mappings use always writecombine */ } else { ret = drm_gem_object_init(dev, obj, size); } if (ret) { drm_gem_private_object_fini(obj); goto err_free; } ret = drm_gem_create_mmap_offset(obj); if (ret) goto err_release; mutex_init(&shmem->pages_lock); mutex_init(&shmem->vmap_lock); INIT_LIST_HEAD(&shmem->madv_list); if (!private) { /* * Our buffers are kept pinned, so allocating them * from the MOVABLE zone is a really bad idea, and * conflicts with CMA. See comments above new_inode() * why this is required _and_ expected if you're * going to pin these pages. */ mapping_set_gfp_mask(obj->filp->f_mapping, GFP_HIGHUSER | __GFP_RETRY_MAYFAIL | __GFP_NOWARN); } return shmem; err_release: drm_gem_object_release(obj); err_free: kfree(obj); return ERR_PTR(ret); } /** * drm_gem_shmem_create - Allocate an object with the given size * @dev: DRM device * @size: Size of the object to allocate * * This function creates a shmem GEM object. * * Returns: * A struct drm_gem_shmem_object * on success or an ERR_PTR()-encoded negative * error code on failure. */ struct drm_gem_shmem_object *drm_gem_shmem_create(struct drm_device *dev, size_t size) { return __drm_gem_shmem_create(dev, size, false); } EXPORT_SYMBOL_GPL(drm_gem_shmem_create); /** * drm_gem_shmem_free - Free resources associated with a shmem GEM object * @shmem: shmem GEM object to free * * This function cleans up the GEM object state and frees the memory used to * store the object itself. */ void drm_gem_shmem_free(struct drm_gem_shmem_object *shmem) { struct drm_gem_object *obj = &shmem->base; drm_WARN_ON(obj->dev, shmem->vmap_use_count); if (obj->import_attach) { drm_prime_gem_destroy(obj, shmem->sgt); } else { if (shmem->sgt) { dma_unmap_sgtable(obj->dev->dev, shmem->sgt, DMA_BIDIRECTIONAL, 0); sg_free_table(shmem->sgt); kfree(shmem->sgt); } if (shmem->pages) drm_gem_shmem_put_pages(shmem); } drm_WARN_ON(obj->dev, shmem->pages_use_count); drm_gem_object_release(obj); mutex_destroy(&shmem->pages_lock); mutex_destroy(&shmem->vmap_lock); kfree(shmem); } EXPORT_SYMBOL_GPL(drm_gem_shmem_free); static int drm_gem_shmem_get_pages_locked(struct drm_gem_shmem_object *shmem) { struct drm_gem_object *obj = &shmem->base; struct page **pages; if (shmem->pages_use_count++ > 0) return 0; pages = drm_gem_get_pages(obj); if (IS_ERR(pages)) { drm_dbg_kms(obj->dev, "Failed to get pages (%ld)\n", PTR_ERR(pages)); shmem->pages_use_count = 0; return PTR_ERR(pages); } /* * TODO: Allocating WC pages which are correctly flushed is only * supported on x86. Ideal solution would be a GFP_WC flag, which also * ttm_pool.c could use. */ #ifdef CONFIG_X86 if (shmem->map_wc) set_pages_array_wc(pages, obj->size >> PAGE_SHIFT); #endif shmem->pages = pages; return 0; } /* * drm_gem_shmem_get_pages - Allocate backing pages for a shmem GEM object * @shmem: shmem GEM object * * This function makes sure that backing pages exists for the shmem GEM object * and increases the use count. * * Returns: * 0 on success or a negative error code on failure. */ int drm_gem_shmem_get_pages(struct drm_gem_shmem_object *shmem) { struct drm_gem_object *obj = &shmem->base; int ret; drm_WARN_ON(obj->dev, obj->import_attach); ret = mutex_lock_interruptible(&shmem->pages_lock); if (ret) return ret; ret = drm_gem_shmem_get_pages_locked(shmem); mutex_unlock(&shmem->pages_lock); return ret; } EXPORT_SYMBOL(drm_gem_shmem_get_pages); static void drm_gem_shmem_put_pages_locked(struct drm_gem_shmem_object *shmem) { struct drm_gem_object *obj = &shmem->base; if (drm_WARN_ON_ONCE(obj->dev, !shmem->pages_use_count)) return; if (--shmem->pages_use_count > 0) return; #ifdef CONFIG_X86 if (shmem->map_wc) set_pages_array_wb(shmem->pages, obj->size >> PAGE_SHIFT); #endif drm_gem_put_pages(obj, shmem->pages, shmem->pages_mark_dirty_on_put, shmem->pages_mark_accessed_on_put); shmem->pages = NULL; } /* * drm_gem_shmem_put_pages - Decrease use count on the backing pages for a shmem GEM object * @shmem: shmem GEM object * * This function decreases the use count and puts the backing pages when use drops to zero. */ void drm_gem_shmem_put_pages(struct drm_gem_shmem_object *shmem) { mutex_lock(&shmem->pages_lock); drm_gem_shmem_put_pages_locked(shmem); mutex_unlock(&shmem->pages_lock); } EXPORT_SYMBOL(drm_gem_shmem_put_pages); /** * drm_gem_shmem_pin - Pin backing pages for a shmem GEM object * @shmem: shmem GEM object * * This function makes sure the backing pages are pinned in memory while the * buffer is exported. * * Returns: * 0 on success or a negative error code on failure. */ int drm_gem_shmem_pin(struct drm_gem_shmem_object *shmem) { struct drm_gem_object *obj = &shmem->base; drm_WARN_ON(obj->dev, obj->import_attach); return drm_gem_shmem_get_pages(shmem); } EXPORT_SYMBOL(drm_gem_shmem_pin); /** * drm_gem_shmem_unpin - Unpin backing pages for a shmem GEM object * @shmem: shmem GEM object * * This function removes the requirement that the backing pages are pinned in * memory. */ void drm_gem_shmem_unpin(struct drm_gem_shmem_object *shmem) { struct drm_gem_object *obj = &shmem->base; drm_WARN_ON(obj->dev, obj->import_attach); drm_gem_shmem_put_pages(shmem); } EXPORT_SYMBOL(drm_gem_shmem_unpin); static int drm_gem_shmem_vmap_locked(struct drm_gem_shmem_object *shmem, struct iosys_map *map) { struct drm_gem_object *obj = &shmem->base; int ret = 0; if (obj->import_attach) { ret = dma_buf_vmap(obj->import_attach->dmabuf, map); if (!ret) { if (drm_WARN_ON(obj->dev, map->is_iomem)) { dma_buf_vunmap(obj->import_attach->dmabuf, map); return -EIO; } } } else { pgprot_t prot = PAGE_KERNEL; if (shmem->vmap_use_count++ > 0) { iosys_map_set_vaddr(map, shmem->vaddr); return 0; } ret = drm_gem_shmem_get_pages(shmem); if (ret) goto err_zero_use; if (shmem->map_wc) prot = pgprot_writecombine(prot); shmem->vaddr = vmap(shmem->pages, obj->size >> PAGE_SHIFT, VM_MAP, prot); if (!shmem->vaddr) ret = -ENOMEM; else iosys_map_set_vaddr(map, shmem->vaddr); } if (ret) { drm_dbg_kms(obj->dev, "Failed to vmap pages, error %d\n", ret); goto err_put_pages; } return 0; err_put_pages: if (!obj->import_attach) drm_gem_shmem_put_pages(shmem); err_zero_use: shmem->vmap_use_count = 0; return ret; } /* * drm_gem_shmem_vmap - Create a virtual mapping for a shmem GEM object * @shmem: shmem GEM object * @map: Returns the kernel virtual address of the SHMEM GEM object's backing * store. * * This function makes sure that a contiguous kernel virtual address mapping * exists for the buffer backing the shmem GEM object. It hides the differences * between dma-buf imported and natively allocated objects. * * Acquired mappings should be cleaned up by calling drm_gem_shmem_vunmap(). * * Returns: * 0 on success or a negative error code on failure. */ int drm_gem_shmem_vmap(struct drm_gem_shmem_object *shmem, struct iosys_map *map) { int ret; ret = mutex_lock_interruptible(&shmem->vmap_lock); if (ret) return ret; ret = drm_gem_shmem_vmap_locked(shmem, map); mutex_unlock(&shmem->vmap_lock); return ret; } EXPORT_SYMBOL(drm_gem_shmem_vmap); static void drm_gem_shmem_vunmap_locked(struct drm_gem_shmem_object *shmem, struct iosys_map *map) { struct drm_gem_object *obj = &shmem->base; if (obj->import_attach) { dma_buf_vunmap(obj->import_attach->dmabuf, map); } else { if (drm_WARN_ON_ONCE(obj->dev, !shmem->vmap_use_count)) return; if (--shmem->vmap_use_count > 0) return; vunmap(shmem->vaddr); drm_gem_shmem_put_pages(shmem); } shmem->vaddr = NULL; } /* * drm_gem_shmem_vunmap - Unmap a virtual mapping for a shmem GEM object * @shmem: shmem GEM object * @map: Kernel virtual address where the SHMEM GEM object was mapped * * This function cleans up a kernel virtual address mapping acquired by * drm_gem_shmem_vmap(). The mapping is only removed when the use count drops to * zero. * * This function hides the differences between dma-buf imported and natively * allocated objects. */ void drm_gem_shmem_vunmap(struct drm_gem_shmem_object *shmem, struct iosys_map *map) { mutex_lock(&shmem->vmap_lock); drm_gem_shmem_vunmap_locked(shmem, map); mutex_unlock(&shmem->vmap_lock); } EXPORT_SYMBOL(drm_gem_shmem_vunmap); static int drm_gem_shmem_create_with_handle(struct drm_file *file_priv, struct drm_device *dev, size_t size, uint32_t *handle) { struct drm_gem_shmem_object *shmem; int ret; shmem = drm_gem_shmem_create(dev, size); if (IS_ERR(shmem)) return PTR_ERR(shmem); /* * Allocate an id of idr table where the obj is registered * and handle has the id what user can see. */ ret = drm_gem_handle_create(file_priv, &shmem->base, handle); /* drop reference from allocate - handle holds it now. */ drm_gem_object_put(&shmem->base); return ret; } /* Update madvise status, returns true if not purged, else * false or -errno. */ int drm_gem_shmem_madvise(struct drm_gem_shmem_object *shmem, int madv) { mutex_lock(&shmem->pages_lock); if (shmem->madv >= 0) shmem->madv = madv; madv = shmem->madv; mutex_unlock(&shmem->pages_lock); return (madv >= 0); } EXPORT_SYMBOL(drm_gem_shmem_madvise); void drm_gem_shmem_purge_locked(struct drm_gem_shmem_object *shmem) { struct drm_gem_object *obj = &shmem->base; struct drm_device *dev = obj->dev; drm_WARN_ON(obj->dev, !drm_gem_shmem_is_purgeable(shmem)); dma_unmap_sgtable(dev->dev, shmem->sgt, DMA_BIDIRECTIONAL, 0); sg_free_table(shmem->sgt); kfree(shmem->sgt); shmem->sgt = NULL; drm_gem_shmem_put_pages_locked(shmem); shmem->madv = -1; drm_vma_node_unmap(&obj->vma_node, dev->anon_inode->i_mapping); drm_gem_free_mmap_offset(obj); /* Our goal here is to return as much of the memory as * is possible back to the system as we are called from OOM. * To do this we must instruct the shmfs to drop all of its * backing pages, *now*. */ shmem_truncate_range(file_inode(obj->filp), 0, (loff_t)-1); invalidate_mapping_pages(file_inode(obj->filp)->i_mapping, 0, (loff_t)-1); } EXPORT_SYMBOL(drm_gem_shmem_purge_locked); bool drm_gem_shmem_purge(struct drm_gem_shmem_object *shmem) { if (!mutex_trylock(&shmem->pages_lock)) return false; drm_gem_shmem_purge_locked(shmem); mutex_unlock(&shmem->pages_lock); return true; } EXPORT_SYMBOL(drm_gem_shmem_purge); /** * drm_gem_shmem_dumb_create - Create a dumb shmem buffer object * @file: DRM file structure to create the dumb buffer for * @dev: DRM device * @args: IOCTL data * * This function computes the pitch of the dumb buffer and rounds it up to an * integer number of bytes per pixel. Drivers for hardware that doesn't have * any additional restrictions on the pitch can directly use this function as * their &drm_driver.dumb_create callback. * * For hardware with additional restrictions, drivers can adjust the fields * set up by userspace before calling into this function. * * Returns: * 0 on success or a negative error code on failure. */ int drm_gem_shmem_dumb_create(struct drm_file *file, struct drm_device *dev, struct drm_mode_create_dumb *args) { u32 min_pitch = DIV_ROUND_UP(args->width * args->bpp, 8); if (!args->pitch || !args->size) { args->pitch = min_pitch; args->size = PAGE_ALIGN(args->pitch * args->height); } else { /* ensure sane minimum values */ if (args->pitch < min_pitch) args->pitch = min_pitch; if (args->size < args->pitch * args->height) args->size = PAGE_ALIGN(args->pitch * args->height); } return drm_gem_shmem_create_with_handle(file, dev, args->size, &args->handle); } EXPORT_SYMBOL_GPL(drm_gem_shmem_dumb_create); static vm_fault_t drm_gem_shmem_fault(struct vm_fault *vmf) { struct vm_area_struct *vma = vmf->vma; struct drm_gem_object *obj = vma->vm_private_data; struct drm_gem_shmem_object *shmem = to_drm_gem_shmem_obj(obj); loff_t num_pages = obj->size >> PAGE_SHIFT; vm_fault_t ret; struct page *page; pgoff_t page_offset; /* We don't use vmf->pgoff since that has the fake offset */ page_offset = (vmf->address - vma->vm_start) >> PAGE_SHIFT; mutex_lock(&shmem->pages_lock); if (page_offset >= num_pages || drm_WARN_ON_ONCE(obj->dev, !shmem->pages) || shmem->madv < 0) { ret = VM_FAULT_SIGBUS; } else { page = shmem->pages[page_offset]; ret = vmf_insert_pfn(vma, vmf->address, page_to_pfn(page)); } mutex_unlock(&shmem->pages_lock); return ret; } static void drm_gem_shmem_vm_open(struct vm_area_struct *vma) { struct drm_gem_object *obj = vma->vm_private_data; struct drm_gem_shmem_object *shmem = to_drm_gem_shmem_obj(obj); drm_WARN_ON(obj->dev, obj->import_attach); mutex_lock(&shmem->pages_lock); /* * We should have already pinned the pages when the buffer was first * mmap'd, vm_open() just grabs an additional reference for the new * mm the vma is getting copied into (ie. on fork()). */ if (!drm_WARN_ON_ONCE(obj->dev, !shmem->pages_use_count)) shmem->pages_use_count++; mutex_unlock(&shmem->pages_lock); drm_gem_vm_open(vma); } static void drm_gem_shmem_vm_close(struct vm_area_struct *vma) { struct drm_gem_object *obj = vma->vm_private_data; struct drm_gem_shmem_object *shmem = to_drm_gem_shmem_obj(obj); drm_gem_shmem_put_pages(shmem); drm_gem_vm_close(vma); } const struct vm_operations_struct drm_gem_shmem_vm_ops = { .fault = drm_gem_shmem_fault, .open = drm_gem_shmem_vm_open, .close = drm_gem_shmem_vm_close, }; EXPORT_SYMBOL_GPL(drm_gem_shmem_vm_ops); /** * drm_gem_shmem_mmap - Memory-map a shmem GEM object * @shmem: shmem GEM object * @vma: VMA for the area to be mapped * * This function implements an augmented version of the GEM DRM file mmap * operation for shmem objects. * * Returns: * 0 on success or a negative error code on failure. */ int drm_gem_shmem_mmap(struct drm_gem_shmem_object *shmem, struct vm_area_struct *vma) { struct drm_gem_object *obj = &shmem->base; int ret; if (obj->import_attach) { /* Drop the reference drm_gem_mmap_obj() acquired.*/ drm_gem_object_put(obj); vma->vm_private_data = NULL; return dma_buf_mmap(obj->dma_buf, vma, 0); } ret = drm_gem_shmem_get_pages(shmem); if (ret) return ret; vma->vm_flags |= VM_PFNMAP | VM_DONTEXPAND | VM_DONTDUMP; vma->vm_page_prot = vm_get_page_prot(vma->vm_flags); if (shmem->map_wc) vma->vm_page_prot = pgprot_writecombine(vma->vm_page_prot); return 0; } EXPORT_SYMBOL_GPL(drm_gem_shmem_mmap); /** * drm_gem_shmem_print_info() - Print &drm_gem_shmem_object info for debugfs * @shmem: shmem GEM object * @p: DRM printer * @indent: Tab indentation level */ void drm_gem_shmem_print_info(const struct drm_gem_shmem_object *shmem, struct drm_printer *p, unsigned int indent) { if (shmem->base.import_attach) return; drm_printf_indent(p, indent, "pages_use_count=%u\n", shmem->pages_use_count); drm_printf_indent(p, indent, "vmap_use_count=%u\n", shmem->vmap_use_count); drm_printf_indent(p, indent, "vaddr=%p\n", shmem->vaddr); } EXPORT_SYMBOL(drm_gem_shmem_print_info); /** * drm_gem_shmem_get_sg_table - Provide a scatter/gather table of pinned * pages for a shmem GEM object * @shmem: shmem GEM object * * This function exports a scatter/gather table suitable for PRIME usage by * calling the standard DMA mapping API. * * Drivers who need to acquire an scatter/gather table for objects need to call * drm_gem_shmem_get_pages_sgt() instead. * * Returns: * A pointer to the scatter/gather table of pinned pages or error pointer on failure. */ struct sg_table *drm_gem_shmem_get_sg_table(struct drm_gem_shmem_object *shmem) { struct drm_gem_object *obj = &shmem->base; drm_WARN_ON(obj->dev, obj->import_attach); return drm_prime_pages_to_sg(obj->dev, shmem->pages, obj->size >> PAGE_SHIFT); } EXPORT_SYMBOL_GPL(drm_gem_shmem_get_sg_table); static struct sg_table *drm_gem_shmem_get_pages_sgt_locked(struct drm_gem_shmem_object *shmem) { struct drm_gem_object *obj = &shmem->base; int ret; struct sg_table *sgt; if (shmem->sgt) return shmem->sgt; drm_WARN_ON(obj->dev, obj->import_attach); ret = drm_gem_shmem_get_pages_locked(shmem); if (ret) return ERR_PTR(ret); sgt = drm_gem_shmem_get_sg_table(shmem); if (IS_ERR(sgt)) { ret = PTR_ERR(sgt); goto err_put_pages; } /* Map the pages for use by the h/w. */ ret = dma_map_sgtable(obj->dev->dev, sgt, DMA_BIDIRECTIONAL, 0); if (ret) goto err_free_sgt; shmem->sgt = sgt; return sgt; err_free_sgt: sg_free_table(sgt); kfree(sgt); err_put_pages: drm_gem_shmem_put_pages_locked(shmem); return ERR_PTR(ret); } /** * drm_gem_shmem_get_pages_sgt - Pin pages, dma map them, and return a * scatter/gather table for a shmem GEM object. * @shmem: shmem GEM object * * This function returns a scatter/gather table suitable for driver usage. If * the sg table doesn't exist, the pages are pinned, dma-mapped, and a sg * table created. * * This is the main function for drivers to get at backing storage, and it hides * and difference between dma-buf imported and natively allocated objects. * drm_gem_shmem_get_sg_table() should not be directly called by drivers. * * Returns: * A pointer to the scatter/gather table of pinned pages or errno on failure. */ struct sg_table *drm_gem_shmem_get_pages_sgt(struct drm_gem_shmem_object *shmem) { int ret; struct sg_table *sgt; ret = mutex_lock_interruptible(&shmem->pages_lock); if (ret) return ERR_PTR(ret); sgt = drm_gem_shmem_get_pages_sgt_locked(shmem); mutex_unlock(&shmem->pages_lock); return sgt; } EXPORT_SYMBOL(drm_gem_shmem_get_pages_sgt); /** * drm_gem_shmem_prime_import_sg_table - Produce a shmem GEM object from * another driver's scatter/gather table of pinned pages * @dev: Device to import into * @attach: DMA-BUF attachment * @sgt: Scatter/gather table of pinned pages * * This function imports a scatter/gather table exported via DMA-BUF by * another driver. Drivers that use the shmem helpers should set this as their * &drm_driver.gem_prime_import_sg_table callback. * * Returns: * A pointer to a newly created GEM object or an ERR_PTR-encoded negative * error code on failure. */ struct drm_gem_object * drm_gem_shmem_prime_import_sg_table(struct drm_device *dev, struct dma_buf_attachment *attach, struct sg_table *sgt) { size_t size = PAGE_ALIGN(attach->dmabuf->size); struct drm_gem_shmem_object *shmem; shmem = __drm_gem_shmem_create(dev, size, true); if (IS_ERR(shmem)) return ERR_CAST(shmem); shmem->sgt = sgt; drm_dbg_prime(dev, "size = %zu\n", size); return &shmem->base; } EXPORT_SYMBOL_GPL(drm_gem_shmem_prime_import_sg_table); MODULE_DESCRIPTION("DRM SHMEM memory-management helpers"); MODULE_IMPORT_NS(DMA_BUF); MODULE_LICENSE("GPL v2");