| // SPDX-License-Identifier: GPL-2.0 |
| /* |
| * DMABUF System heap exporter |
| * |
| * Copyright (C) 2011 Google, Inc. |
| * Copyright (C) 2019, 2020 Linaro Ltd. |
| * |
| * Portions based off of Andrew Davis' SRAM heap: |
| * Copyright (C) 2019 Texas Instruments Incorporated - http://www.ti.com/ |
| * Andrew F. Davis <afd@ti.com> |
| */ |
| |
| #include <linux/dma-buf.h> |
| #include <linux/dma-mapping.h> |
| #include <linux/dma-heap.h> |
| #include <linux/err.h> |
| #include <linux/highmem.h> |
| #include <linux/mm.h> |
| #include <linux/module.h> |
| #include <linux/scatterlist.h> |
| #include <linux/slab.h> |
| #include <linux/vmalloc.h> |
| |
| static struct dma_heap *sys_heap; |
| |
| struct system_heap_buffer { |
| struct dma_heap *heap; |
| struct list_head attachments; |
| struct mutex lock; |
| unsigned long len; |
| struct sg_table sg_table; |
| int vmap_cnt; |
| void *vaddr; |
| }; |
| |
| struct dma_heap_attachment { |
| struct device *dev; |
| struct sg_table *table; |
| struct list_head list; |
| bool mapped; |
| }; |
| |
| #define LOW_ORDER_GFP (GFP_HIGHUSER | __GFP_ZERO | __GFP_COMP) |
| #define MID_ORDER_GFP (LOW_ORDER_GFP | __GFP_NOWARN) |
| #define HIGH_ORDER_GFP (((GFP_HIGHUSER | __GFP_ZERO | __GFP_NOWARN \ |
| | __GFP_NORETRY) & ~__GFP_RECLAIM) \ |
| | __GFP_COMP) |
| static gfp_t order_flags[] = {HIGH_ORDER_GFP, MID_ORDER_GFP, LOW_ORDER_GFP}; |
| /* |
| * The selection of the orders used for allocation (1MB, 64K, 4K) is designed |
| * to match with the sizes often found in IOMMUs. Using order 4 pages instead |
| * of order 0 pages can significantly improve the performance of many IOMMUs |
| * by reducing TLB pressure and time spent updating page tables. |
| */ |
| static const unsigned int orders[] = {8, 4, 0}; |
| #define NUM_ORDERS ARRAY_SIZE(orders) |
| |
| static struct sg_table *dup_sg_table(struct sg_table *table) |
| { |
| struct sg_table *new_table; |
| int ret, i; |
| struct scatterlist *sg, *new_sg; |
| |
| new_table = kzalloc(sizeof(*new_table), GFP_KERNEL); |
| if (!new_table) |
| return ERR_PTR(-ENOMEM); |
| |
| ret = sg_alloc_table(new_table, table->orig_nents, GFP_KERNEL); |
| if (ret) { |
| kfree(new_table); |
| return ERR_PTR(-ENOMEM); |
| } |
| |
| new_sg = new_table->sgl; |
| for_each_sgtable_sg(table, sg, i) { |
| sg_set_page(new_sg, sg_page(sg), sg->length, sg->offset); |
| new_sg = sg_next(new_sg); |
| } |
| |
| return new_table; |
| } |
| |
| static int system_heap_attach(struct dma_buf *dmabuf, |
| struct dma_buf_attachment *attachment) |
| { |
| struct system_heap_buffer *buffer = dmabuf->priv; |
| struct dma_heap_attachment *a; |
| struct sg_table *table; |
| |
| a = kzalloc(sizeof(*a), GFP_KERNEL); |
| if (!a) |
| return -ENOMEM; |
| |
| table = dup_sg_table(&buffer->sg_table); |
| if (IS_ERR(table)) { |
| kfree(a); |
| return -ENOMEM; |
| } |
| |
| a->table = table; |
| a->dev = attachment->dev; |
| INIT_LIST_HEAD(&a->list); |
| a->mapped = false; |
| |
| attachment->priv = a; |
| |
| mutex_lock(&buffer->lock); |
| list_add(&a->list, &buffer->attachments); |
| mutex_unlock(&buffer->lock); |
| |
| return 0; |
| } |
| |
| static void system_heap_detach(struct dma_buf *dmabuf, |
| struct dma_buf_attachment *attachment) |
| { |
| struct system_heap_buffer *buffer = dmabuf->priv; |
| struct dma_heap_attachment *a = attachment->priv; |
| |
| mutex_lock(&buffer->lock); |
| list_del(&a->list); |
| mutex_unlock(&buffer->lock); |
| |
| sg_free_table(a->table); |
| kfree(a->table); |
| kfree(a); |
| } |
| |
| static struct sg_table *system_heap_map_dma_buf(struct dma_buf_attachment *attachment, |
| enum dma_data_direction direction) |
| { |
| struct dma_heap_attachment *a = attachment->priv; |
| struct sg_table *table = a->table; |
| int ret; |
| |
| ret = dma_map_sgtable(attachment->dev, table, direction, 0); |
| if (ret) |
| return ERR_PTR(ret); |
| |
| a->mapped = true; |
| return table; |
| } |
| |
| static void system_heap_unmap_dma_buf(struct dma_buf_attachment *attachment, |
| struct sg_table *table, |
| enum dma_data_direction direction) |
| { |
| struct dma_heap_attachment *a = attachment->priv; |
| |
| a->mapped = false; |
| dma_unmap_sgtable(attachment->dev, table, direction, 0); |
| } |
| |
| static int system_heap_dma_buf_begin_cpu_access(struct dma_buf *dmabuf, |
| enum dma_data_direction direction) |
| { |
| struct system_heap_buffer *buffer = dmabuf->priv; |
| struct dma_heap_attachment *a; |
| |
| mutex_lock(&buffer->lock); |
| |
| if (buffer->vmap_cnt) |
| invalidate_kernel_vmap_range(buffer->vaddr, buffer->len); |
| |
| list_for_each_entry(a, &buffer->attachments, list) { |
| if (!a->mapped) |
| continue; |
| dma_sync_sgtable_for_cpu(a->dev, a->table, direction); |
| } |
| mutex_unlock(&buffer->lock); |
| |
| return 0; |
| } |
| |
| static int system_heap_dma_buf_end_cpu_access(struct dma_buf *dmabuf, |
| enum dma_data_direction direction) |
| { |
| struct system_heap_buffer *buffer = dmabuf->priv; |
| struct dma_heap_attachment *a; |
| |
| mutex_lock(&buffer->lock); |
| |
| if (buffer->vmap_cnt) |
| flush_kernel_vmap_range(buffer->vaddr, buffer->len); |
| |
| list_for_each_entry(a, &buffer->attachments, list) { |
| if (!a->mapped) |
| continue; |
| dma_sync_sgtable_for_device(a->dev, a->table, direction); |
| } |
| mutex_unlock(&buffer->lock); |
| |
| return 0; |
| } |
| |
| static int system_heap_mmap(struct dma_buf *dmabuf, struct vm_area_struct *vma) |
| { |
| struct system_heap_buffer *buffer = dmabuf->priv; |
| struct sg_table *table = &buffer->sg_table; |
| unsigned long addr = vma->vm_start; |
| struct sg_page_iter piter; |
| int ret; |
| |
| for_each_sgtable_page(table, &piter, vma->vm_pgoff) { |
| struct page *page = sg_page_iter_page(&piter); |
| |
| ret = remap_pfn_range(vma, addr, page_to_pfn(page), PAGE_SIZE, |
| vma->vm_page_prot); |
| if (ret) |
| return ret; |
| addr += PAGE_SIZE; |
| if (addr >= vma->vm_end) |
| return 0; |
| } |
| return 0; |
| } |
| |
| static void *system_heap_do_vmap(struct system_heap_buffer *buffer) |
| { |
| struct sg_table *table = &buffer->sg_table; |
| int npages = PAGE_ALIGN(buffer->len) / PAGE_SIZE; |
| struct page **pages = vmalloc(sizeof(struct page *) * npages); |
| struct page **tmp = pages; |
| struct sg_page_iter piter; |
| void *vaddr; |
| |
| if (!pages) |
| return ERR_PTR(-ENOMEM); |
| |
| for_each_sgtable_page(table, &piter, 0) { |
| WARN_ON(tmp - pages >= npages); |
| *tmp++ = sg_page_iter_page(&piter); |
| } |
| |
| vaddr = vmap(pages, npages, VM_MAP, PAGE_KERNEL); |
| vfree(pages); |
| |
| if (!vaddr) |
| return ERR_PTR(-ENOMEM); |
| |
| return vaddr; |
| } |
| |
| static int system_heap_vmap(struct dma_buf *dmabuf, struct dma_buf_map *map) |
| { |
| struct system_heap_buffer *buffer = dmabuf->priv; |
| void *vaddr; |
| int ret = 0; |
| |
| mutex_lock(&buffer->lock); |
| if (buffer->vmap_cnt) { |
| buffer->vmap_cnt++; |
| dma_buf_map_set_vaddr(map, buffer->vaddr); |
| goto out; |
| } |
| |
| vaddr = system_heap_do_vmap(buffer); |
| if (IS_ERR(vaddr)) { |
| ret = PTR_ERR(vaddr); |
| goto out; |
| } |
| |
| buffer->vaddr = vaddr; |
| buffer->vmap_cnt++; |
| dma_buf_map_set_vaddr(map, buffer->vaddr); |
| out: |
| mutex_unlock(&buffer->lock); |
| |
| return ret; |
| } |
| |
| static void system_heap_vunmap(struct dma_buf *dmabuf, struct dma_buf_map *map) |
| { |
| struct system_heap_buffer *buffer = dmabuf->priv; |
| |
| mutex_lock(&buffer->lock); |
| if (!--buffer->vmap_cnt) { |
| vunmap(buffer->vaddr); |
| buffer->vaddr = NULL; |
| } |
| mutex_unlock(&buffer->lock); |
| dma_buf_map_clear(map); |
| } |
| |
| static void system_heap_dma_buf_release(struct dma_buf *dmabuf) |
| { |
| struct system_heap_buffer *buffer = dmabuf->priv; |
| struct sg_table *table; |
| struct scatterlist *sg; |
| int i; |
| |
| table = &buffer->sg_table; |
| for_each_sgtable_sg(table, sg, i) { |
| struct page *page = sg_page(sg); |
| |
| __free_pages(page, compound_order(page)); |
| } |
| sg_free_table(table); |
| kfree(buffer); |
| } |
| |
| static const struct dma_buf_ops system_heap_buf_ops = { |
| .attach = system_heap_attach, |
| .detach = system_heap_detach, |
| .map_dma_buf = system_heap_map_dma_buf, |
| .unmap_dma_buf = system_heap_unmap_dma_buf, |
| .begin_cpu_access = system_heap_dma_buf_begin_cpu_access, |
| .end_cpu_access = system_heap_dma_buf_end_cpu_access, |
| .mmap = system_heap_mmap, |
| .vmap = system_heap_vmap, |
| .vunmap = system_heap_vunmap, |
| .release = system_heap_dma_buf_release, |
| }; |
| |
| static struct page *alloc_largest_available(unsigned long size, |
| unsigned int max_order) |
| { |
| struct page *page; |
| int i; |
| |
| for (i = 0; i < NUM_ORDERS; i++) { |
| if (size < (PAGE_SIZE << orders[i])) |
| continue; |
| if (max_order < orders[i]) |
| continue; |
| |
| page = alloc_pages(order_flags[i], orders[i]); |
| if (!page) |
| continue; |
| return page; |
| } |
| return NULL; |
| } |
| |
| static struct dma_buf *system_heap_allocate(struct dma_heap *heap, |
| unsigned long len, |
| unsigned long fd_flags, |
| unsigned long heap_flags) |
| { |
| struct system_heap_buffer *buffer; |
| DEFINE_DMA_BUF_EXPORT_INFO(exp_info); |
| unsigned long size_remaining = len; |
| unsigned int max_order = orders[0]; |
| struct dma_buf *dmabuf; |
| struct sg_table *table; |
| struct scatterlist *sg; |
| struct list_head pages; |
| struct page *page, *tmp_page; |
| int i, ret = -ENOMEM; |
| |
| buffer = kzalloc(sizeof(*buffer), GFP_KERNEL); |
| if (!buffer) |
| return ERR_PTR(-ENOMEM); |
| |
| INIT_LIST_HEAD(&buffer->attachments); |
| mutex_init(&buffer->lock); |
| buffer->heap = heap; |
| buffer->len = len; |
| |
| INIT_LIST_HEAD(&pages); |
| i = 0; |
| while (size_remaining > 0) { |
| /* |
| * Avoid trying to allocate memory if the process |
| * has been killed by SIGKILL |
| */ |
| if (fatal_signal_pending(current)) { |
| ret = -EINTR; |
| goto free_buffer; |
| } |
| |
| page = alloc_largest_available(size_remaining, max_order); |
| if (!page) |
| goto free_buffer; |
| |
| list_add_tail(&page->lru, &pages); |
| size_remaining -= page_size(page); |
| max_order = compound_order(page); |
| i++; |
| } |
| |
| table = &buffer->sg_table; |
| if (sg_alloc_table(table, i, GFP_KERNEL)) |
| goto free_buffer; |
| |
| sg = table->sgl; |
| list_for_each_entry_safe(page, tmp_page, &pages, lru) { |
| sg_set_page(sg, page, page_size(page), 0); |
| sg = sg_next(sg); |
| list_del(&page->lru); |
| } |
| |
| /* create the dmabuf */ |
| exp_info.exp_name = dma_heap_get_name(heap); |
| exp_info.ops = &system_heap_buf_ops; |
| exp_info.size = buffer->len; |
| exp_info.flags = fd_flags; |
| exp_info.priv = buffer; |
| dmabuf = dma_buf_export(&exp_info); |
| if (IS_ERR(dmabuf)) { |
| ret = PTR_ERR(dmabuf); |
| goto free_pages; |
| } |
| return dmabuf; |
| |
| free_pages: |
| for_each_sgtable_sg(table, sg, i) { |
| struct page *p = sg_page(sg); |
| |
| __free_pages(p, compound_order(p)); |
| } |
| sg_free_table(table); |
| free_buffer: |
| list_for_each_entry_safe(page, tmp_page, &pages, lru) |
| __free_pages(page, compound_order(page)); |
| kfree(buffer); |
| |
| return ERR_PTR(ret); |
| } |
| |
| static const struct dma_heap_ops system_heap_ops = { |
| .allocate = system_heap_allocate, |
| }; |
| |
| static int system_heap_create(void) |
| { |
| struct dma_heap_export_info exp_info; |
| |
| exp_info.name = "system"; |
| exp_info.ops = &system_heap_ops; |
| exp_info.priv = NULL; |
| |
| sys_heap = dma_heap_add(&exp_info); |
| if (IS_ERR(sys_heap)) |
| return PTR_ERR(sys_heap); |
| |
| return 0; |
| } |
| module_init(system_heap_create); |
| MODULE_LICENSE("GPL v2"); |