Commit a20f507f authored by Christoph Hellwig's avatar Christoph Hellwig Committed by Michael Ellerman
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powerpc/dma: untangle vio_dma_mapping_ops from dma_iommu_ops 



vio_dma_mapping_ops currently does a lot of indirect calls through
dma_iommu_ops, which not only make the code harder to follow but are
also expensive in the post-spectre world.  Unwind the indirect calls
by calling the ppc_iommu_* or iommu_* APIs directly applicable, or
just use the dma_iommu_* methods directly where we can.

Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
parent fbce251b

arch/powerpc/include/asm/iommu.h

+1 −0
Original line number Diff line number Diff line
@@ -237,6 +237,7 @@ static inline void iommu_del_device(struct device *dev) 
}

#endif /* !CONFIG_IOMMU_API */



u64 dma_iommu_get_required_mask(struct device *dev);

#else



static inline void *get_iommu_table_base(struct device *dev)

arch/powerpc/kernel/dma-iommu.c

+1 −1
Original line number Diff line number Diff line
@@ -92,7 +92,7 @@ int dma_iommu_dma_supported(struct device *dev, u64 mask) 
		return 1;

}



static u64 dma_iommu_get_required_mask(struct device *dev)

u64 dma_iommu_get_required_mask(struct device *dev)

{

	struct iommu_table *tbl = get_iommu_table_base(dev);

	u64 mask;

arch/powerpc/platforms/pseries/vio.c

+36 −51
Original line number Diff line number Diff line
@@ -492,7 +492,9 @@ static void *vio_dma_iommu_alloc_coherent(struct device *dev, size_t size, 
		return NULL;

	}



	ret = dma_iommu_ops.alloc(dev, size, dma_handle, flag, attrs);

	ret = iommu_alloc_coherent(dev, get_iommu_table_base(dev), size,

				    dma_handle, dev->coherent_dma_mask, flag,

				    dev_to_node(dev));

	if (unlikely(ret == NULL)) {

		vio_cmo_dealloc(viodev, roundup(size, PAGE_SIZE));

		atomic_inc(&viodev->cmo.allocs_failed);
@@ -507,8 +509,7 @@ static void vio_dma_iommu_free_coherent(struct device *dev, size_t size, 
{

	struct vio_dev *viodev = to_vio_dev(dev);



	dma_iommu_ops.free(dev, size, vaddr, dma_handle, attrs);



	iommu_free_coherent(get_iommu_table_base(dev), size, vaddr, dma_handle);

	vio_cmo_dealloc(viodev, roundup(size, PAGE_SIZE));

}
@@ -518,22 +519,22 @@ static dma_addr_t vio_dma_iommu_map_page(struct device *dev, struct page *page, 
                                         unsigned long attrs)

{

	struct vio_dev *viodev = to_vio_dev(dev);

	struct iommu_table *tbl;

	struct iommu_table *tbl = get_iommu_table_base(dev);

	dma_addr_t ret = DMA_MAPPING_ERROR;



	tbl = get_iommu_table_base(dev);

	if (vio_cmo_alloc(viodev, roundup(size, IOMMU_PAGE_SIZE(tbl)))) {

		atomic_inc(&viodev->cmo.allocs_failed);

	if (vio_cmo_alloc(viodev, roundup(size, IOMMU_PAGE_SIZE(tbl))))

		goto out_fail;

	ret = iommu_map_page(dev, tbl, page, offset, size, device_to_mask(dev),

			direction, attrs);

	if (unlikely(ret == DMA_MAPPING_ERROR))

		goto out_deallocate;

	return ret;

	}



	ret = dma_iommu_ops.map_page(dev, page, offset, size, direction, attrs);

	if (unlikely(dma_mapping_error(dev, ret))) {

out_deallocate:

	vio_cmo_dealloc(viodev, roundup(size, IOMMU_PAGE_SIZE(tbl)));

out_fail:

	atomic_inc(&viodev->cmo.allocs_failed);

	}



	return ret;

	return DMA_MAPPING_ERROR;

}



static void vio_dma_iommu_unmap_page(struct device *dev, dma_addr_t dma_handle,
@@ -542,11 +543,9 @@ static void vio_dma_iommu_unmap_page(struct device *dev, dma_addr_t dma_handle, 
				     unsigned long attrs)

{

	struct vio_dev *viodev = to_vio_dev(dev);

	struct iommu_table *tbl;



	tbl = get_iommu_table_base(dev);

	dma_iommu_ops.unmap_page(dev, dma_handle, size, direction, attrs);

	struct iommu_table *tbl = get_iommu_table_base(dev);



	iommu_unmap_page(tbl, dma_handle, size, direction, attrs);

	vio_cmo_dealloc(viodev, roundup(size, IOMMU_PAGE_SIZE(tbl)));

}
@@ -555,34 +554,32 @@ static int vio_dma_iommu_map_sg(struct device *dev, struct scatterlist *sglist, 
                                unsigned long attrs)

{

	struct vio_dev *viodev = to_vio_dev(dev);

	struct iommu_table *tbl;

	struct iommu_table *tbl = get_iommu_table_base(dev);

	struct scatterlist *sgl;

	int ret, count;

	size_t alloc_size = 0;



	tbl = get_iommu_table_base(dev);

	for_each_sg(sglist, sgl, nelems, count)

		alloc_size += roundup(sgl->length, IOMMU_PAGE_SIZE(tbl));



	if (vio_cmo_alloc(viodev, alloc_size)) {

		atomic_inc(&viodev->cmo.allocs_failed);

		return 0;

	}



	ret = dma_iommu_ops.map_sg(dev, sglist, nelems, direction, attrs);



	if (unlikely(!ret)) {

		vio_cmo_dealloc(viodev, alloc_size);

		atomic_inc(&viodev->cmo.allocs_failed);

		return ret;

	}

	if (vio_cmo_alloc(viodev, alloc_size))

		goto out_fail;

	ret = ppc_iommu_map_sg(dev, tbl, sglist, nelems, device_to_mask(dev),

			direction, attrs);

	if (unlikely(!ret))

		goto out_deallocate;



	for_each_sg(sglist, sgl, ret, count)

		alloc_size -= roundup(sgl->dma_length, IOMMU_PAGE_SIZE(tbl));

	if (alloc_size)

		vio_cmo_dealloc(viodev, alloc_size);



	return ret;



out_deallocate:

	vio_cmo_dealloc(viodev, alloc_size);

out_fail:

	atomic_inc(&viodev->cmo.allocs_failed);

	return 0;

}



static void vio_dma_iommu_unmap_sg(struct device *dev,
@@ -591,30 +588,18 @@ static void vio_dma_iommu_unmap_sg(struct device *dev, 
		unsigned long attrs)

{

	struct vio_dev *viodev = to_vio_dev(dev);

	struct iommu_table *tbl;

	struct iommu_table *tbl = get_iommu_table_base(dev);

	struct scatterlist *sgl;

	size_t alloc_size = 0;

	int count;



	tbl = get_iommu_table_base(dev);

	for_each_sg(sglist, sgl, nelems, count)

		alloc_size += roundup(sgl->dma_length, IOMMU_PAGE_SIZE(tbl));



	dma_iommu_ops.unmap_sg(dev, sglist, nelems, direction, attrs);



	ppc_iommu_unmap_sg(tbl, sglist, nelems, direction, attrs);

	vio_cmo_dealloc(viodev, alloc_size);

}



static int vio_dma_iommu_dma_supported(struct device *dev, u64 mask)

{

        return dma_iommu_ops.dma_supported(dev, mask);

}



static u64 vio_dma_get_required_mask(struct device *dev)

{

        return dma_iommu_ops.get_required_mask(dev);

}



static const struct dma_map_ops vio_dma_mapping_ops = {

	.alloc             = vio_dma_iommu_alloc_coherent,

	.free              = vio_dma_iommu_free_coherent,
@@ -623,8 +608,8 @@ static const struct dma_map_ops vio_dma_mapping_ops = { 
	.unmap_sg          = vio_dma_iommu_unmap_sg,

	.map_page          = vio_dma_iommu_map_page,

	.unmap_page        = vio_dma_iommu_unmap_page,

	.dma_supported     = vio_dma_iommu_dma_supported,

	.get_required_mask = vio_dma_get_required_mask,

	.dma_supported     = dma_iommu_dma_supported,

	.get_required_mask = dma_iommu_get_required_mask,

};



/**

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