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Commit 27975969 authored by Christoph Hellwig's avatar Christoph Hellwig
Browse files

dma-direct: add dma address sanity checks 



Roughly based on the x86 pci-nommu implementation.

Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
parent 2e86a047

lib/dma-direct.c

+30 −1
Original line number Diff line number Diff line
@@ -9,6 +9,23 @@ 
#include <linux/scatterlist.h>

#include <linux/pfn.h>



#define DIRECT_MAPPING_ERROR		0



static bool

check_addr(struct device *dev, dma_addr_t dma_addr, size_t size,

		const char *caller)

{

	if (unlikely(dev && !dma_capable(dev, dma_addr, size))) {

		if (*dev->dma_mask >= DMA_BIT_MASK(32)) {

			dev_err(dev,

				"%s: overflow %pad+%zu of device mask %llx\n",

				caller, &dma_addr, size, *dev->dma_mask);

		}

		return false;

	}

	return true;

}



static void *dma_direct_alloc(struct device *dev, size_t size,

		dma_addr_t *dma_handle, gfp_t gfp, unsigned long attrs)

{
@@ -31,7 +48,11 @@ static dma_addr_t dma_direct_map_page(struct device *dev, struct page *page, 
		unsigned long offset, size_t size, enum dma_data_direction dir,

		unsigned long attrs)

{

	return phys_to_dma(dev, page_to_phys(page)) + offset;

	dma_addr_t dma_addr = phys_to_dma(dev, page_to_phys(page)) + offset;



	if (!check_addr(dev, dma_addr, size, __func__))

		return DIRECT_MAPPING_ERROR;

	return dma_addr;

}



static int dma_direct_map_sg(struct device *dev, struct scatterlist *sgl,
@@ -44,16 +65,24 @@ static int dma_direct_map_sg(struct device *dev, struct scatterlist *sgl, 
		BUG_ON(!sg_page(sg));



		sg_dma_address(sg) = phys_to_dma(dev, sg_phys(sg));

		if (!check_addr(dev, sg_dma_address(sg), sg->length, __func__))

			return 0;

		sg_dma_len(sg) = sg->length;

	}



	return nents;

}



static int dma_direct_mapping_error(struct device *dev, dma_addr_t dma_addr)

{

	return dma_addr == DIRECT_MAPPING_ERROR;

}



const struct dma_map_ops dma_direct_ops = {

	.alloc			= dma_direct_alloc,

	.free			= dma_direct_free,

	.map_page		= dma_direct_map_page,

	.map_sg			= dma_direct_map_sg,

	.mapping_error		= dma_direct_mapping_error,

};

EXPORT_SYMBOL(dma_direct_ops);