cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
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ops_helpers.c (2560B)

      1// SPDX-License-Identifier: GPL-2.0
      2/*
      3 * Helpers for DMA ops implementations.  These generally rely on the fact that
      4 * the allocated memory contains normal pages in the direct kernel mapping.
      5 */
      6#include <linux/dma-map-ops.h>
      7
      8static struct page *dma_common_vaddr_to_page(void *cpu_addr)
      9{
     10	if (is_vmalloc_addr(cpu_addr))
     11		return vmalloc_to_page(cpu_addr);
     12	return virt_to_page(cpu_addr);
     13}
     14
     15/*
     16 * Create scatter-list for the already allocated DMA buffer.
     17 */
     18int dma_common_get_sgtable(struct device *dev, struct sg_table *sgt,
     19		 void *cpu_addr, dma_addr_t dma_addr, size_t size,
     20		 unsigned long attrs)
     21{
     22	struct page *page = dma_common_vaddr_to_page(cpu_addr);
     23	int ret;
     24
     25	ret = sg_alloc_table(sgt, 1, GFP_KERNEL);
     26	if (!ret)
     27		sg_set_page(sgt->sgl, page, PAGE_ALIGN(size), 0);
     28	return ret;
     29}
     30
     31/*
     32 * Create userspace mapping for the DMA-coherent memory.
     33 */
     34int dma_common_mmap(struct device *dev, struct vm_area_struct *vma,
     35		void *cpu_addr, dma_addr_t dma_addr, size_t size,
     36		unsigned long attrs)
     37{
     38#ifdef CONFIG_MMU
     39	unsigned long user_count = vma_pages(vma);
     40	unsigned long count = PAGE_ALIGN(size) >> PAGE_SHIFT;
     41	unsigned long off = vma->vm_pgoff;
     42	struct page *page = dma_common_vaddr_to_page(cpu_addr);
     43	int ret = -ENXIO;
     44
     45	vma->vm_page_prot = dma_pgprot(dev, vma->vm_page_prot, attrs);
     46
     47	if (dma_mmap_from_dev_coherent(dev, vma, cpu_addr, size, &ret))
     48		return ret;
     49
     50	if (off >= count || user_count > count - off)
     51		return -ENXIO;
     52
     53	return remap_pfn_range(vma, vma->vm_start,
     54			page_to_pfn(page) + vma->vm_pgoff,
     55			user_count << PAGE_SHIFT, vma->vm_page_prot);
     56#else
     57	return -ENXIO;
     58#endif /* CONFIG_MMU */
     59}
     60
     61struct page *dma_common_alloc_pages(struct device *dev, size_t size,
     62		dma_addr_t *dma_handle, enum dma_data_direction dir, gfp_t gfp)
     63{
     64	const struct dma_map_ops *ops = get_dma_ops(dev);
     65	struct page *page;
     66
     67	page = dma_alloc_contiguous(dev, size, gfp);
     68	if (!page)
     69		page = alloc_pages_node(dev_to_node(dev), gfp, get_order(size));
     70	if (!page)
     71		return NULL;
     72
     73	*dma_handle = ops->map_page(dev, page, 0, size, dir,
     74				    DMA_ATTR_SKIP_CPU_SYNC);
     75	if (*dma_handle == DMA_MAPPING_ERROR) {
     76		dma_free_contiguous(dev, page, size);
     77		return NULL;
     78	}
     79
     80	memset(page_address(page), 0, size);
     81	return page;
     82}
     83
     84void dma_common_free_pages(struct device *dev, size_t size, struct page *page,
     85		dma_addr_t dma_handle, enum dma_data_direction dir)
     86{
     87	const struct dma_map_ops *ops = get_dma_ops(dev);
     88
     89	if (ops->unmap_page)
     90		ops->unmap_page(dev, dma_handle, size, dir,
     91				DMA_ATTR_SKIP_CPU_SYNC);
     92	dma_free_contiguous(dev, page, size);
     93}